IHU,.IR-3273

TECHNICAL REPORT BRL-TR-3273

BRLPENETRATION OF SHAI’ED-CHARGE JETSINTO GLASS ANI) CRYS7’ALLINE QUARTZ

G. [;. IIA(JV1;l<P. 11. Nli’1’f II;l<}v(x)[)

R. F. EIENCKA. MEI.ANI

U.S. ARMY LABOI<A’I’OR}” COMMAND

BALLISTIC RESEARCH LABORATORY

ABERDEEN PROVING GROUND, MARYLAND

BRL·TR·3273

• •

ntE copy

TECHNICAL REPORT BRL-TR-3273

PENETRATION OF SHAPED-CHARGE JETS INTO GLASS AND CRYSTALLINE QUARTZ

G. E. IIAUVER P. II. NETIIERWOOD

R. F. BENCK A. I\lELA['\!

S E PTEivlB E R j()l) 1

APPROVED FOR PUBLIC RI'LI'i\SF; DISTRIIll' no" IS U:'-:UMITI'D.

U.S. ARMY LABORATORY COMMAND

BALLISTIC RESEARCH LABORATORY

ABERDEEN PROVING GROUND, MARYLAND

NOTICES

Destroy this report when it is no Iongcr needed. DO NOT return it to the originator.

Additional copies of tt]is report may be obtained from the Nation:]l Technical Informa!lon S(?rvlcc,

U.S. Department of Commcrc[; , 5285 Port RoyGl Road, Springfield, VA 22161

The findings of this report are not to k construed ,X an of fic]al Department of tile Army posltlon,

unless so design atccj by other authorized documents

The use of trade names or mar~ufacturcrs’ names Ir) tt]is r[eport does not consti[~lte lmdorse[]lcf)t

of any commercial product.

NOTICES

Destroy this report wrlen it is no longer needed. DO NOT return it to the origin3tor.

Additional copies of this report rn3y be obt3ined frorn the N3tional TechniC(l1 Information S(;rvlcc. U.S. Dep3rtrnent of Cornrnerce, 5285 Port Royal Road, Sprirlgfield, VA 22161

The findings of this report are not to be construed 3S 3n officl;]1 Ocp3rtrnent of ttle Arrny position, unless so design3tcci by otrwr 3uthorized documents

The use of tr3de names or m3flufacturers' n3fTlCS in trlis report does not corlstltllte Ifldorseflleflt of any cornrnerci31 product.

REPORT DOCUMENTATION PAGEform Approval

(IMB No i2/OJ 0188

Penetration of Shaped-Charge Jets Into Glass and Crystalline Quartz

6. AUTHOR(S)

G. E. Hauver, P. H. Netherwood, R. F. Benck, and A. Melani

7. PERFORMING ORGANIZATION NAME(S) AND AOORESS(E5)

DirectorU.S. Army Ballistic Research LaboratoryATTN: SLCBR-TB-AMAberdeen Proving Ground, MD 21005-5066

1L161102AH43

8. PERFORMING ORGANIZATIONREPORT NUMBER

19. SPONSORING MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING MONITORING

AGENCY REPORT NUMBER

U.S. Army Ballistic Research LaboratoryATTN: SLCBR-DD-TAberdeen Proving Ground, MD 21005-5066

BRL-TR-327 3

12a. DISTRIBUTION AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited.

I13. ABSTRACT (Max/mum 200 words)

Penetration of shaped charge jets into glass and crystalline quartz was studied by high-speed photographyand flash radiography to identify behavior responsible for the effectiveness of glass against shaped chargethreats. The behavior of crystalline quartz was relatively conventional. The greater effectiveness of silica andhigh-silica glasses was clearly indicated by an abrupt decrease in penetration velocity shortly after impact.High-speed photographs showed that the penetration path opened to its maximum diameter within a fewmicroseconds and then rapidly closed after the penetration front passed. The penetration velocity decreasedwhen jet elements, disturbed by cavity closure, arrived at the penetration front. The penetration path inrecovered targets was filled with a red copper-glass that resulted from an extended interaction between jet andtarget materials, Closure preceded brittle failure in the surrounding glass target, and it was concluded thatprimary closure is caused by recovery from high pressures near the penetration front.

14. SUBJECT TERMS 15 NUMBER OF PAGES

59penetration; jets; shaped-charge jets; glass; quartz; cavity closure 16 PRICE COOE

17. SECURITY CLASSIFICATION 18 SECURITY CLASSIFICATION 19 SF CURITY CLASSIFICATION 20 LIMITATION OF ABSTRAC1OF REPORT OF THIS PAGE OF ABSTRACT

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED SARUSPJ754001 :80 5’)01)

UNCLASSIFIED\+c+flcjdrdirr~.’98RWJ?H9j,,, (1,-! :, .,.J! !11 * I h!I! ‘w’,

IINr.1 A~~IFIED DOCUMENTATION PAGE

form Approv('d REPORT OMB No 01040188

PiJOJI' rl'p ,rl I' ; t'l. r ~, '1 ~ ,r :' 1 " It' ' 'C' t ., 'CC,' " ,,1 l""1j"-':' , " ""

, , c J',' ; P!' 1'-',," r 'I', >',', '11 ,r",:' J' :1, '1', ", p, "". I ,-. ',1"1 I : Il,! , ",r ",

l IT r~'( r 1 1 'i ~ 1 \ r • I r I , 1 11 1 I I ". "~" j I, j 11-.,,'111'; Ii" ",', , ,

" " "-I,i ., .... ,,''1 r., I " I \, :11 I rr, ~ :)I,r,jl'rl I" I' rT ar, II" p'!'[ j"~)" t ,t """ \ Iit'd' .'1 • ,.t, 11'- \T\ ,11)\ .'\ J "",1" r"j,,'I"l')

" '" , ,'. l',I' • , ~ l' l ". ·'1 " ',r·',· ",1" (,' r't '1'l'1 tl', '1' I ,[",pr dl ,I" jl d H"r,' r~ ,''J,.jt''I\,'rl

I I"" I ~ I j 1'1' " t I ,j I'" ., .: ",Ir ll' II .. '.' ,\,' , 'ii,' 1 j 1 !'o> ." t -,11 1,"" . , ' I :jl I' 'r "'I .', " I~' 'I j I, t I' " f " i'" • ; IJ 'i 1,1 11' ,>4,M J '/\' 1', l' r lit r' 1\ .')',1,)1

1. AGENCY USE ONL Y (l t'JVt' hlank) -,2 REPORT DATE 13. REPORT TYPE AND DATES COVERED

September 19lJ 1 Final, January 1984-January 1989

4, TITLE AND SUBTITLE 5. FUNDING NUMBERS

Penetration of Shaped-Charge Jets Into Glass and Crystalline Quartz

6, AUTHOR(S) 1L161102AH43

G. E. Hauver, P. H. Netherwood, R F. Benck, and A. Melani

7, PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PE RFORMING ORGANIZA TION

Director REPORT NUMBER

U,S. Army Ballistic Research Laboratory AnN: SLCBR-TB-AM Aberdeen Proving Ground, MD 21005-5066

9. SPONSORING MONITORING AGENCY NAME(S) AND ADDRESS(ES) 1O, SPONSORING i MONITORING AGENCY REPORT NUMBER

U,S. Army Ballistic Research Laboratory BRL-TR-327 3

AnN: SLCBR-DD-T Aberdeen Proving Ground, MD 21005-5066

11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION AVAILABILITY STAHMENT 12b. DISTRIBUTION CODE

Approved for public release; distribution is unlimited,

13, ABSTRACT (MaXImum 200 words)

Penetration of shaped charge jets into glass and crystalline quartz was studied by high-speed photography and flash radiography to identify behavior responsible for the effectiveness of glass against shaped charge threats. The behavior of crystalline quartz was relatively conventional. The greater effectiveness of silica and high-silica glasses was clearly indicated by an abrupt decrease in penetration velocity shortly after impact. High-speed photographs showed that the penetration path opened to its maximum diameter within a few microseconds and then rapidly closed after the penetration front passed, The penetration velocity decreased when jet elements, disturbed by cavity closure, arrived at the penetration front. The penetration path in recovered targets was filled with a red copper-glass that resulted from an extended interaction between jet and target materials. Closure preceded brittle failure in the surrounding glass target, and it was concluded that primary closure is caused by recovery from high pressures near the penetration front.

14, SUBJECT TERMS 15 NUMBER OF PAGES

59 penetration; jets; shaped-charge jets; glass; quartz; cavity closure 16. PRICE CODE

17, SECURITY ClASSIFICATION 18. SECURITY CLASSIFICA TlON 19 Sf CURITY ClASSIFICA TION 20. LIMITATION OF J\BSTRACT OF REPORT OF THIS PAGE OF ABSTRACT

UNCLASSIFIED UNCLASSI FI ED UNCLASSIFIED SAR , ,

UNCLASSIFIED \ '\. ' ,) :' ~ • \ t l " , 1 1 -\' ~ '"I

• 1K 'IJ.1

il

INTfcNflONALLY II r r 131ANK

II

TABLE OF CONTENTS

Ei3Q

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. EXPERIMENTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1

2.2

2.3

2.4

2.4.1

2.4.2

2.4.3

2.5

2.6

2.7

2.8

Test Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Examination of Penetration-Time Data . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flash-Radiographic Observations During Jet Penetration . . . . . . , . . . . . .

Photographic Measurementsof Penetration-Time . . . . . . . . . . . . . . .

Experimental Configurations for Photographic Studies . . . . . . . . .

Jet Penetration Into Fused Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Jet Penetration Into Soda-Lime Glass . . . . . . . . . . . . . . . . . . . . . . . . . .

Examination of Recovered Glass Targets . . . . . . . . . . . . . . . . . .

Formation and Role of Red Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Test for Permanent Densification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Examination of Recovered Crystalline Quartz Targets . . . . . . . . . . . . . . . .

3. SUMMARY AND FINAL DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DISTRIBUTION LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii

1

2

2

3

3

8

911

16

3242

44

46

46

51

53

Ill

TABLE OF CONTENTS

LIST OF FIGURES ........................................... v

ACKNOWLEDGMENTS .............. . . . . . . . . . . . . . . . . . . . . . . . . . . vii

1. INTRODUCTION ............................................ .

2.

2.1 2.2 2.3 2.4 2.4.1 2.4.2 2.4.3 2.5 2.6 2.7 2.8

3.

4.

EXPERIMENTS AND DISCUSSION .............................. .

Test Charge ............................................. . Examination of Penetration-Time Data .......................... . Flash-Radiographic Observations During Jet Penetration ............. . Photographic Measurements of Penetration-Time .................. .

Experimental Configurations for Photographic Studies ............. . Jet Penetration Into Fused Quartz ........................... . Jet Penetration Into Soda-Lime Glass ......................... .

Examination of Recovered Glass Targets ........................ . Formation and Role of Red Glass .............................. . Test for Permanent Densification .............................. . Examination of Recovered Crystalline Quartz Targets ............... .

SUMMARY AND FINAL DISCUSSION ............................ .

REFERENCES ............................................. .

2

2 3 3 8 9

11 16 32 42 44 46

46

51

DISTRIBUTION LIST ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

iii

Iv

INTE N IIONAl lY l Ff T RLANK.

IV

LIST OF FIGURES

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

Photograph of a Glass Target During Penetration by a Shaped Charge Jet . .

Target Configurations for Radiographic Tests . . . . . . . . . . . . . . . .

Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and(B) Crystalline Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Profiles of Optical Density Across Penetration Paths in (A) Fused Quartz and(B) Crystalline Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Configuration for Photographic Tests With Back Lighting . . . . . . . . . . . . . . . .

Configuration for Photographic Tests With Front Lighting . . . . . . . . . . . . . . . .

Penetration-Time Data for the Initial Part of Jet Penetration Into FusedQuartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combined Radiographic and Photographic Data for Jet Penetration IntoFused Quartz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz(FQ)and Crystalline Quartz (CQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Photographs of a Soda-Lime Glass Target During Penetration by aContinuous Jet (Test I ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Penetration-Time Data for the Jet Penetration Shown in Figure 10 . . . . . . . . .

Photographs of a Soda-Lime Glass Target During Penetration by aContinuous Jet(Test 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Penetration-Time Data for the Jet Penetration Shown in Figure 12 . . . . . . . . .

Path Diameter as a Function of Time (Continuous Jets) . . . . . . . . . . . . . .

Penetration-Time Curves From Figure 13, Including a Path for the JetElement That Arrives at the Transition Point . . . . . . . . . . . . . . . . . . . . .

Photographs of a Soda-Lime Glass Target During Penetration by aParticulated Jet(Test l) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Path Diameter as a Function of Time (Particulate Jet) . . . . . . . . . . . . . . . . .

Penetration-Time Data for the Jet Penetration Shown in Figure 16 . . . . . . . .

v

!2.!?Q

2

4

5

7

9

10

12

13

15

17

18

20

21

22

23

24

26

27

LIST OF FIGURES

Figure

1 . Photograph of a Glass Target During Penetration by a Shaped Charge Jet 2

2. Target Configurations for Radiographic Tests ........................ . 4

3. Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and (B) Crystalline Quartz ....................................... . 5

4. Profiles of Optical Density Across Penetration Paths in (A) Fused Quartz and (B) Crystalline Quartz ....................................... . 7

5. Configuration for Photographic Tests With Back Lighting 9

6. Configuration for Photographic Tests With Front Lighting 10

7. Penetration-Time Data for the Initial Part of Jet Penetration Into Fused Quartz ................................................. . 12

8. Combined Radiographic and Photographic Data for Jet Penetration Into Fused Quartz ............................................ . 13

9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FQ) and Crystalline Quartz (CQ) .............................. . 15

10. Photographs of a Soda-Lime Glass Target During Penetration by a Continuous Jet (Test 1) ..................................... . 17

11. Penetration-Time Data for the Jet Penetration Shown in Figure 10 ........ . 18

12. Photographs of a Soda-Lime Glass Target During Penetration by a Continuous Jet (Test 2) ..................................... . 20

13. Penetration-Time Data for the Jet Penetration Shown in Figure 12 ........ . 21

14. Path Diameter as a Function of Time (Continuous Jets) ................ . 22

15. Penetration-Time Curves From Figure 13, Including a Path for the Jet Element That Arrives at the Transition Point ...................... . 23

16. Photographs of a Soda-Lime Glass Target During Penetration by a Particulated Jet (Test 1) ..................................... . 24

17. Path Diameter as a Function of Time (Particulated Jet) ................ . 26

18. Penetration-Time Data for the Jet Penetration Shown in Figure 16 27

v

1!3. Photographs of a Soda Lime Glass Target During Penetration by a

Particulated Jet(Test 2) ..,..... . 28

29Penetration Time Data for the Jet Penetration Shown in Figure 1920.

21. Back-Lighted Photographs of a Soda-Lime Glass Target During Penetration

bya Particulated Jet(Test 3)... . 30

3122.

23.

Penetration Time Data for the Jet Penetration Shown in Figure 21

Photograpt~s of a Monolithic Soda-Lime Glass Target During Penetration by

aParticulated Jet(Test 4).... . 33

34Penetration Time Data for the Jet Penetration Shown in Figure 2324.

25. Fused Quartz Target Sectioned to Expose the Penetration Path Filled With

Rcd Glass..,..,.. .

26. (A) Static R:dograpt) of the Penetration Path in Fused Quartz: (B) SEM

Micrograph of Fled Glass From the Pen[:tration Path Irl Fused Quartz

27. Red Glass That Flowed From tile Back of a Perforated Fused Quartz

Target . . 38

28. Recovcrcd [argot of Boroslhcate Glass St~owlng Red Glass Displaced When

the Slug l:ntercd the Target . . . . .

Glass Targe:s Penetrated by (A) a Copper Jet, (B) a Steel Jet, and (C) In

Aluminum Jet. (D) is a Deposit of Material Ejected Frorr] tllc Pc[lutratlon

Path ln (C.. .

29.

40

41

43

Tapered Jet Particles In Red Glass30.

31.

32.

Data of Meade and Jeanloz

Target Cor]figuration Used to Recover Per[lla[lc[)tly Denslfied Fused

Quartz .

(A) Static Radiograph] of tt]e Crystalline Quartz Target; (B D) Arc Cross

Suctions of the Target III (A) Showing Cavity Closurt:

33.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33

Photographs of a Soda Lime Glass Target During Penetration by a Particulated Jet (Test 2)

Penetration Tirne Data for the Jet Penetration Shown in Figure 19

Backlighted Photographs of a Soda-Lirne Glass Target During Penetration by a Particulated Jet (Test 3) ...

Penetration Time Data for the Jet Penetration Shown in Figure 21

Photographs of a Monolithic Soda·Lirne Glass Target During Pelletr<ltion by a Particulated Jet (Test 4)

Penetration Tirne Data for the Jet Penetration Shown in Figure 23

Fused Quartz Target Sectioned to Expose trw Penetration Path Filled With Red Glass ..

(A) Static Rddiograpl1 of the Penetration Path in Fused Quartz: (B) St=M Micrograph of Red Glass Frorn the Penetration Path in Fused Quartz

Red Glass That Flowed Frorn the Back of a Perforated Fused Quartz Target

Recovered r arget of Borosilicate Glass SI10wing Rud Glass Displacud Wlwn the Slug E:ntered the Target

Glass Targe:s Penetrated by (A) a Copper Jet. (B) a Steel Jet. and (C) ,111

AlurninulT1 Jet. (D) is a Deposit of Material Ejected From tlw Pelwtratl011

Path in Ie)

Tapered Jet Particles in Red Glass

Data of Meade and Jeanloz

Target COl1figuration U~;ed to Recover P8rlnJner1tly Denslfied Fw,ed

Quartz

(A) Static Radiograph of the Crystalline Quartz Target: (B D) Are Cross Sections of Itw Target III (A) Showing Cavity Closurl:

VI

28

29

30

31

II

34

39

40

41

43

ACKNOWLEDGMENT

The authors are indebted to Dr. W. Bruchey who obtained the analysis of red glass, and to

Ms. D. Montiel who provided the SEM micrograph of red glass which appears as Figure 26B.

vii

ACKNOWLEDGMENT

The authors are indebted to Dr. W. Bruchey who obtained the analysis of red glass, and to

Ms. D. Montiel who provided the SEM micrograph of red glass which appears as Figure 26B.

vii

IN II- NT IONAI.LY LFFT BLANK.

Vlll

IN1~NrIONAU Y LFFT mANK

VIII

1. INTRODUCTION

Experiments performed at the Carnegie Institute of Technology (CIT) during World War II

showed that glass has an unusual ability to resist penetration by shaped charge jets. After

World War 11,Pugh and his associates at CIT studied the performance of glass targets and

established general principles (Heine-Geldern 1954; Allison 1960) that apply to the use of

glass for shaped charge protection. However, the physical behavior underlying these

principles remained obscure. The studies described in this report were undertaken to identify

dynamic behavior responsible for the effectiveness of glass targets.

As an introduction to the recent studies, it may be useful to examine Figure 1, which is a

photograph from a 1955 publication (Zernow and Hauver 1955). This back-lighted photograph

shows an unconfined glass target as it is penetrated by a small copper jet. The most

prominent features in the photograph are (A) the central dark region, (B) the dark envelope

that resembles a bow wave, (C) the envelope of trailing fracture, and (D) the impact shock

which is still visible at the lower extremes. The central dark region was assumed to define the

penetration path. The penetration velocity of the jet in Figure 1 is subsonic, so the only shock

wave is the one produced at impact. Consequently, the envelope that resembles a bow wave

must have another origin. Earlier Kerr-Cell photographs at CIT (Pugh et al. 1951) clearly

showed that this envelope encloses a cylindrical volume around the penetration path in soda-

Iime glass.

Concurrent with the CIT investigations, Bridgman and Simon (1953) discovered that fused

quartz and other glasses become permanently densified under static compression at high

pressure. Since that time, many studies of permanent densification under static and dynamic

compression have been conducted, including Viard (1959), Wackerle (1962), Cohen and Roy

(1965), Arndt, Hornemann, and Muller (1971), Gibbons and Ahrens (1971), Anan’in et al.

(1974a), Kanel, Molodets, and Dremin (1 976), Cagnoux (1 981), and Sugiura, Kondo, and

Sawaoka (1981) which are considered most pertinent to the present investigation. In the

present investigation, particles ejected from a fused quartz target during jet penetration were

found to be permanently densified by up to 10O/~. This observation supports the assumption

that the envelope surrounding the penetration path is a boundary between glass which is

1

1. INTRODUCTION

Experiments performed at the Carnegie Institute of Technology (CIT) during World War II

showed that glass has an unusual ability to resist penetration by shaped charge jets. After

World War II, Pugh and his associates at CIT studied the performance of glass targets and

established general principles (Heine-Geldern 1954; Allison 1960) that apply to the use of

glass for shaped charge protection. However, the physical behavior underlying these

principles remained obscure. The studies described in this report were undertaken to identify

dynamic behavior responsible for the effectiveness of glass targets.

As an introduction to the recent studies, it may be useful to examine Figure 1, which is a

photograph from a 1955 publication (Zernow and Hauver 1955). This back-lighted photograph

shows an unconfined glass target as it is penetrated by a small copper jet. The most

prominent features in the photograph are (A) the central dark region, (B) the dark envelope

that resembles a bow wave, (C) the envelope of trailing fracture, and (D) the impact shock

which is still visible at the lower extremes. The central dark region was assumed to define the

penetration path. The penetration velocity of the jet in Figure 1 is subsonic, so the only shock

wave is the one produced at impact. Consequently, the envelope that resembles a bow wJ.ve

must have another origin. Earlier Kerr-Cell photographs at CIT (Pugh et al. 1951) cieJ.rly

showed that this envelope encloses a cylindrical volume around the penetration path in soda­

lime glass.

Concurrent with the CIT investigations, Bridgman and Simon (1953) discovered that fused

quartz and other glasses become permanently densified under static compression at high

pressure. Since that time, many studies of permanent densification under static and dynamiC

compression have been conducted, including Viard (1959), Wackerle (1962), Cohen and Roy

(1965), Arndt, Hornemann, and Muller (1971), Gibbons and Ahrens (1971), Anan'in et al.

(1974a), Kanel, Molodets, and Dremin (1976), Cagnoux (1981), and Sugiura, Kondo, and

Sawaoka (1981) which are considered most pertinent to the present investigation. In the

present investigation, particles ejected from a fused quartz target during jet penetration were

found to be permanently densified by up to 10%. This observation supports the assumption

that the envelope surrounding the penetration path is a boundary between glass which is

~5mm~

Figure 1. Photograph of a Glass Target During Penetration by a Shaped Charge Jet.

elastically deformed and glass which has yielded to become permanently densified. In

Figure 1, permanently densified glass resides between the envelope (B) and the penetration

path (A).

Tests were recently conducted with targets of glass and crystalline quartz to obtain further

information about jet-target interactions. These tests used flash radiography and high-speed

photography to observe behavior during penetration. In the tests that used flash radiography,

metallic confinement allowed the targets to be recovered for post-test examinations which

further helped to identify behavior. These recent tests will be described and discussed in the

following sections of the report.

2. EXPERIMENTS AND DISCUSSION

2.1 Test Charge. Most of the penetration experiments were conducted with the jet from a

shaped charge liner with a base diameter of 35 mm. This liner was obtained by reducing the

2

base diameter of an obsolete M9A1 copper cone which had an apex angle of 42” and a

nominal wall thickness of 0.89 mm. The explosive was unconfined Composition B

(diameter =35 mm) which extended to 1.5 tin]os ttlc cone height. This explosive was initiated

by a PBX booster (diameter = 19 mm; height 13 mln) in combination with an Ml 8 detonator.

An earlier study (Hauver and Benson 1955) showed that an Ml 8 improves the axial symmetry

of a detonation wave, mainly by restricting the area over which the booster is initiated. The

primary detonator contained PETN powder wtlic!l was initiated by an exploding bridgewire.

The velocity of the jet tip was approximately 7,830 Ills, and during free flight, breakup

occurred approximately 20.7 y.s after the jet emOrg[}d from the base of the liner, producing

particles with an average length of 2.6 mm (Franz and Lawrence 1987).

2.2 Examination of Penetration-Time D<~a]. Data for depth of penetration as a function of

time were always examined with the aid of a Modified Bernoulli Model (Tate 1967, 1969),

assuming a virtual origin and a linear distribution of velocity along the jet. The jet was

assumed to elongate until the breakup time determined experimentally during free flight in air.

At breakup, the jet was subdivided into segments with the average length determined

experimentally. During free flight, segments were assumed to maintain both their assigned

length and their axial alignment. In metallic targets. the target-strength term in the model is

defined as the quasi-static pressure, R, required to open a spherical cavity frorm zero initial

radius. In applying the model to glass targets, R was considered only as a measure of

resistance to penetration, and it served as a fitting parameter. In this method of application,

values for R were clearly dependent not only on the target material, but also on jet behavior

and details of the jet-target interaction. Basically, the simple model has no realistic means for

treating the complexity of penetration in a glass target. Despite a loss of fundamental

significance, values of R were useful for comparing one test with another, and for locating

changes in penetration behavior during a single test. Reasons for changes in the value of R

were then subject to interpretation based on experimental evidence. The stress unit is

included with R values cited in the text, as a formality, but it is omitted in figures where

relative magnitudes of R are of primary interest.

2.3 Flash-Radiographic Observations During Jet Penetration. Jet penetration into targets

of fused quartz and crystalline quartz was observed by 450-kV flash radiography. Targets for

the flash-radiographic tests are shown in Figure 2. Although target configurations (A) and (B)

3

base diameter of an obsolete M9A 1 copper cone which had an apex angle of 42' and a

nominal wall thickness of 0.89 mm. The explosive was unconfined Composition B

(diameter = 35 mm) which extended to 1.5 time:; the cone height. This explosive was initiJ.ted

by a PBX booster (diameter = 19 mm; height 13 mm) in combination with an M18 detonator.

An earlier study (Hauver and Benson 1955) stlowed that an M18 improves the axial symmetry

of a detonation wave, mainly by restricting the mea over which the booster is initiated. The

primary detonator contained PETN powder whictl was initiated by an exploding bridgewire.

The velocity of the jet tip was approximately 7,830 Ill/s, and during free flight, breakup

occurred approximately 20.7 ~tS after the jet emerged from the base of the liner, producing

particles with an average length of 2.6 mm (Franz and Lawrence 1987).

2.2 Examination of Penetration-Time QQ1r Data for depth of penetration as a function of

time were always examined with the aid of a Modifil~d Bernoulli Model (Tate 1967, 1969),

assuming a virtual origin and a linear distribution of velocity along the jet. The jet was

assumed to elongate until the breakup time determined experimentally during free fligtlt in air.

At breakup, the jet was subdivided into segments with the average length determined

experimentally. During free flight, segments were assumed to maintain both their assigned

length and their axial alignment. In metallic targets. the target-strength term in the model is

defined as the quasi-static pressure, R, required to open a spherical cavity from zero initial

radius. In applying the model to glass targets, R was considered only as a measure of

resistance to penetration, and it served as a fitting parameter. In this method of application,

values for R were clearly dependent not only on the target material, but also on jet behavior

and details of the jet-target interaction. Basically. tile simple model has no realistic means for

treating the complexity of penetration in a glass target. Despite a loss of fundamental

significance, values of R were useful for comparing one test with another, and for locating

changes in penetration behavior during a single test. Reasons for changes in the value of R

were then subject to interpretation based on experimental evidence. The stress unit is

included with R values cited in the text, as a formality, but it is omitted in figures where

relative magnitudes of R are of primary interest.

2.3 Flash-Radiographic Observations During Jet Penetration. Jet penetration into targets

of fused quartz and crystalline quartz was observed by 450-kV flash radiography. Targets for

the flash-radiographic tests are shown in Figure 2. Although target configurations (A) and (B)

3

—————

38mm

DIAMETER

__-L.-—._.ALUMINUM

—

II

I

‘!=------ 102“m ~— .—

STEEL

38rnm

DIAMETER

ALUMINUM

7075T6AL

I

B

Figure 2. Tarqet Configurations for Radloqraphic Tests.-.

were both used for tests with fused quartz, only configuration (A) wos [Iscd for tests wIttl

crystalhne quartz. “[IIc small size of ttIc jet (1 O 1,5 rnnl dlanletcr), tllc l~?;lterl(~l of thu jet

{c;opper~, tlIe relatively Iargu x r,l’y $,OLJFCC SIZC (5 O ITIIII dl:j[ll(:tl’rl. :Illd :;[; clttcr(:d fcidl:itlorl

contributed to imagng pro ble[~ls, arid httle detail could bu discerned befort~ tr:~cer materl;]l was

introduced into targets. Different tracer materials and configur:ltions w[:rc tcstod. and

rad~ographs of jet penetration into targets containing tracers arc showrl irl ~ lgur(} 3

TIIC target rnutcrlal in F-lgure 3A IS fused quartz with a den:;ity of 2.2(1 FJIg[11’, and tt]c

tracer material is lead glass. Penetration has proceeded from top to bottoin Irl the figure

Although pcnetratlorl has advanced beyond the lower tracer, dctwls rlear tl]e punetratlor) frorlt

are not well de finccl and the jet can be resolved only {above th~> upper tracer where It is clcnrly

disrupted. Tracer rnaterl:il has flowed Into th[~ target (toward the bottom of tllc figure) and

dcflncs portions of the penetration path. Displaced tracer rT]~]tcrl;]l IS not concentrated :Ilo IIg

4

: _ [ A\UMINUM I

--r--~ . ----1 F -~-r--,--

i STEEL_ I I , I r--------~

38mm DIAMETER

ALUMINUM

7075T6 AL

---------------.--. ------'

A

~-------I I ,

----102 mm ------'1

I STEEL ------r-

I 7075T6

I AL

38 rnm I DIAMETER I

i'l.LUMINUM L---____ ~ ____ . __ ~ _______________ _

B

r.:.igure 2 Target Configurations for RadiographicTests,

were both used for tests wiHI fused qU3rtz, only configuration (A) WZ1S lls(;d for u;sts wiO]

crystalline quartz, -rile small size of ttle Jct (1 0 1,5 1111ll diameter), Hie 1]1(!tIHIZll ot tilL: Jl;t

(copper), \tIt: rt;latlvely largf.; j ray ~jource Sill: (50 ITHli dlallll:tl'!I, ~lI1d ~;cdttL:r(;d r,ldl~ltlon

contributed to imaging problems, ,md little dutail could bu discerrwd beforl: tracer material was

introduced Into targets Different tracer materials and configurrltions we:rl! tc:stf'd, and

radiogr3phs of Jet penetration into targets containing tracers ar,; shown in r-igure 3

TIl(; target matcri31 in F~igure 3A IS fused qU3rtz wiHl a den~;ity of 2:?O ~J1grll', and ttlL:

tracer material is le3d glass Penetration has proceeded from top to bottorn In tlw figurL:

Although penetration has advanced beyond tile lower tracer, dl!talls rwar Hll; pL:rwtratioll front

arc not well detinuel and Ole Jet can be resolved only above tiw uppc;r tracer wllere It is CII;iUly

disrupted Tracer rnaterial has flowud Into the target (toward Oil; bottorn of tile figure,! and

duflrlCs portions of ttw penetration pan] Displaced traCL:r 1T1;l!l;rlal is 110t COIlCL:lltratod alollg

4

r-IOmm -l

Figure 3. Flash Radiographs Showing Jet Penetration Into (A) Fused Quartz and (8) Crystalline Quartz.

5

the wall of the penetration path. The arrows in Figure 3A indicate the location of optical

density measurements across the image of the penetration path, and Figure 4A shows the

density change, ,~D, as a function of distance. A uniform distribution of absorbing material

within the path woulId be expected to produce the dashed profile. The measured profile is

sirnllar, but asymmetry is present and is probably caused by displaced jet lnaterlal Tt]e

displaced jet matcrlal IS seen above the upper tracer, and its location is In qL~allt,itlvc

agrcelnent witt] tllc asymnletry, although the jet carlnot be resolved at tt]e location of derlwfy

measurcmfents Tt]e penetration path between tile two upper tracers has ;] di[il~leter of

:lppr Oxltllrltt?ly .5 rr]l~ wtlif. tl was corlfirnlcd Wt![!rl ttlc rccovc’rcd tilrgt>t w,l$; sf:cl Ion(xj nrld

rT7C;lSU[L?d.

the wall of the penetration path. The arrows in Figure 3A indicate the location of optical

density measurements across the image of the penetration path, and Figure 4A shows ttw

density change, /\0, as a function of distance. A uniform distribution of absorbing material

within the path would be expected to produce the dashed profile. The measured profile is

similar, but asymmetry is present arld is probably caused by displaced jct material Trlc

displaced Jet material IS seen above the upper traccr, and its location is ill quallt<ltlvc

agrc(]lnent with HII: asymmetry, although the wt cannot be resolvf]d at \118 location ot dUII:;lly

mf:a:;urulm;nts TIlE: penetration patti between tllU two upper tracers has () c1izlIllclur ot

apprOxllTldtl:ly 5 rTlll. whidl was COfllirrTl(;d Wll(:fl till: r(]Cl)vcrud target Wd~; sc:ctll)lwd zlild

measured

TliI: tcuc]d III fi(jIHf: 30 is polycrystallirw qUelfl: Willi d dl'rlSlty of 2 (i<l f'l.1CJ Ill" :me) Hit'

tr,lu'r Ill:ltl;II,11 I', LllltdllHl1 CJrblc1c: ((:f,lIlIie I ';old ql,I:;:; tfdCl;r:~ Wl:f(: Ilot u:;l'd 1!1 (lrd .. 'r tu

i',·()"j ,lilY C1II';lIl1c'rpI':LltICHI tlidt 11l1(]llt rl;';ult f!UIII tlt:I'dVIUI clldldrtl:rl:;tl(. of ql,l:', f"'III'tl,I1I I.'11

:1:(0 II t·Ll!'::." q::,I'L~ ,1PPfl,tr', tu r)C 1110[(; COII/l;lltluILII ttldll Pl;'llItfdtIOIl ,11(11 lu' I'd qu.IrL'

rill' ,t I ,If' tH' (II" IIIJ w;I:i'rj ,It !II<' IWI]fltrdtloll flll!1 ,lild III Ilt'll II dl:~pl,11 I'd trUI'i tilt' 11.'lltl.:1

tl,IU" '!I)pf'cl': t,; i· I i)11l:I'I:t1dtl;ri.ilUllq ttil' r;'l, • .."Iil Till' d"( Iv 1:: i ICj .. 'I; :H I;'d .1:>' !Ii"

:I!: rj(",c':I', 1,'!lHl" \'1,.1 ,I 'IJr'(t!(HI ell ril' j 1"( f' Ti", ti,I;,I!>'I) Ii' ." I" 1111 ',' 1,' ,i· j"

!df'(l1171'(j d,:' '.,t, ;1'::11'1' It· I: 'N(;uld~)I' "'P!',.l\'(] I' It,' u:III'(l 'll ,t.,,, I: \V'" ,"' , !

NIH] d dl,lfTlf 1,;1 Ii! 1 ;' 'Ill" ;F,j .! tllt)1 Wltll ,lI' ;lld' "11 Ill. WII'!! 'I .)1.) q, Iii" 1'1: .,,: I

, ; i' j C ; t I!'; '1 cl :.,!! I d ( Ii' CJ r , I~) Ii! I: r i(] I:;' ~ fJ (h f" '1 () t I: r : .• I ri 1 (i, 'cl I ,"y'! cJ I 'i HY I) ~ :. d. : J i' 1! Jr l '

riurillCJ PI;I'I;\rd\IUI: dltllOuql1 clo:;url Wd'; fOLHId III 111(' rc;covL:rc'd LnC]!:t

TIl(; loc;ltiofl:~ fO' denSity scans In FIC)lJrf;~~ 3 ;Hld 4 WLire flat :1rbrtrclrlly (',I ·illl I! 'CJ 111l'Y

W(}rr: :;(:If:c1(;d to lilw.;tratu 11IO:;t cludrly thfi CpJillt;!tIV(; OIY,l'rvdtloflS about (j,:;tllllllh,rl'; uf I,'t

dnd tingf;t Illd!f,lld, Nillilfl pl;rH;trdti()[l P;]tiIS Ifl fil:;('d qu.Htz dfld uyst;llllll1' qL1,lIt' If] til(' (,1:;(:

of fused l1uartz. thL' most SUitable location was bctwcurl ttw upper two tracers Gec:lLJse of

6

0.( “

‘6m, --..,- -

)0-! I ! 1 I3

1-4 5

UI>IANLL , mrn

A

-0’*8~–- 1 r

-0.06

I d.-,.\

{’ 1\\,’

I

/ \\:

1 T;/

// 1<

-o,02- 1“I!4I

1 1 13 4 5 fi

DISTANCE , mm

B

Figure 4. Profiles of Optical Density Across Pf:tlt:trat!orl Potlls in (A) Fused Quortz ond {B)

Crystalline Qunrtz.

7

o <1

0 <1

-0.10

-0.08

-0.06

-0.04

-0.02

0.000

-0.08

-0.06

-0.04

I

I

I I

I I

I

I

I

I I

I /

\

/ /

\

/

/

/

/

2 3 DISTANCE

A

'- ... , I

\

I \ \

\

I ... 'J 1-

... , , , , , , \

4 mm

5 6

0000!:------------:2~-----:3=---4~---':5~-~6

DISTANCE mm B

Figure 4. Profiles of Optici11 Density Across P(:lldrzll!on Patils in (A) Fused QUZ"Jrtz and (8) Crysti1lline Quartz.

7

low image contrast, a location closer to the upper tracer provided a higher concentration of

tracer material and Improved the contrast for measurements. In the case of crystalllnu quirt~,

the critical location was between the central tracer and the next lower tracer. Qualitatively, tt~e

jet was visible (In the original radiograph) within this entire region. However, tracer matcrlal

was more concentrated close to the central tracer, so the density scan was conducted at Itlls

location where it could benefit from improved image contrast.

Strain fields are observed to be different in the fused quartz and crystalline quartz tarq[:ts

shown in Figure 3. In fused quartz, displacement at the bottom surface of tracers deflncs a

column with a dlarmeter of 9-10 mm which, in high s[lica glasses, corresponds closely to tt~c

diameter of the en~elope containing permanently densified material. In crystalline quartz,

displaced material at the bottom surface of tracers defines a column wtth a larger diameter of

15–16 mm, It is assumed that large displacements in crystalline quartz were associated with

failure Into particle$; or microblocks (Anan’in et al. 1974b) which were subsequently displ:~ced.

Displaced particles should not fit together compactly, and this represents a source of dllatar]cy

ti~at might produce cavity closure However, Figure 3B suggests that cavity closure in

crystalline quartz does not proceed rapidly since there is no clear evidence of closure {it this

stage of the penetration.

2.4 Photo~raphlc hAea SLJre~TICntS -Qf Penc?tral!on Tl[ne. J[:t penctr~tlo[l l!lto glass w;i;

observed by higtl speed photography irl an effort to examine th[: pcnctratlor] pattl n[>ar tt]u

penctrtitior] frorlt wtlcre flasl! radiograpl]s did not provide w[;II d[fIncd f(:,itur~::, 111fu~j IJ,Irt;

Tt~e Inltlal photogr;~plllc studlcs were conductecj wltt~ blocks of fused quart?, but l,~ttr :tuj( :;

used targets of commercial soda lime glass. Thu blocks of fused quartz offered gooc oI)tIL:,iI

quallty and no interfaces where failure could be initiated by the impact shock. However,

fracture propagated at a velocity nearly equal to the penetratiorl veloclty r] fUS(2d quartz nr)d

quickly obscured details near tile penetration front, making this material ;I poor CI1OICC?for

optical studies Despite this short corlllng. fused qu(~rtz was of Interest bt’cciu:;~) If I)c]s b~’(1[1

the subject of ITIJIIy Illgl) pressure studies and offers a dlrcct co[nparson wltt] pcnctratlc[l

behavior in crystalhne quartz. In later tests with sodalirne glass, the penetration vclo[lfy

greatly exceeded the fracture velocity during the early part of penetration. Photographs of tt~e

exposed penetration path in soda-lime glass provided insight into behavior during jet

8

low image contrast, a location closer to the upper tracer provided a higtler concentration ot

tracer material and Improved the contrast for measurements. In the case of crystalline qu,lrt7,

the critical location was between the central tracer and ttle next lower tracer. Qualitatively, the

jet was visible (in the original radiograph) within ttlis entire region. However, tracer rnateml

was more concentrated close to the central tracer, so the density scan was conducted at ttliS

location where it could benefit from improved image contrast.

Strain fields are observed to be different in the fused quartz and crystalline quartz t;lrC)(ds

shown in Figure 3. In fused quartz, displacement at the bottorn surface of trGcers dctrn(;s Zl

column with a diameter of 9-10 mm which, in high silica glasses, corresponds closely to till':

diameter of the envelope containing permanently densified material. In crystalline quartz,

displaced material at the bottom surface of tracers defines a column With a Idrger diameter of

15-16 mm. It is assumed that large displacements in crystalline quartz were 3ssociated witll

failure Into particles or microblocks (Anan'in et al. 1974b) which were subsequently displaced.

Displaced particles should not fit together compactly, and this represents a source of dilatHlcy

tilat might produce cavity closure However. Figure 38 suggests tt13t cavity closure in

crystalline quartz does not proceed rapidly slflce trlCre is no clear evidence of closure Zit tllis

stage of the penetration

2.4 PrlOtographic MeasurerncntsQf PerlQ1f'~ltloJl __ lIiTl_Q J(:t pcnetr,ltloll l[ltO CJI;I~-:;S w;r;

observed by high ~;peed photography in em (;ffort to examine the fwnetratiofl path near till.:

perwtrutlon front wtlere flash radiographs did not prOVide wf;11 o('flncd f(~,itLJrl;~, 1[1 fll'l.:tJ !lUcHt'

Tt1C mitlal prlotoCjr:lptllc studies were conducted Wlttl blocks of fused qUdrtz, tJUt I,lll'r :tUrJd :;

used t3rgets of cornrnerciClI soda lime gI3SS. TIll' blocks of fused quartz otfcr(;d good optlcdl

quality and no interfaces where failure could be initiated by the impact shock. However,

fracture propagated at a velocity nearly equal to the penetration velOCity In fused quartz Zlnd

quickly obscured details ncar the pcrwtration front, making \tlis material (l poor cl10ice for

optical studl(;s Despite \tlis sllortco[ning. fused quartz was of interest oec,lu:;L' it lIas OL:I;[l

the subject of fTJdlly high prussuw studies iHld ofters 3 direct cornp,1rison wltll pcrwtr,ltIC[l

behaVior in crystalline quartz. In later tests Witrl soda lime glass, the penetration vdocity

greatly exceeded the fracture velocity during the early part of penetration. Photographs of tile

exposed penetration path in soda~lime glass provided insight into behavior during jet

8

penetration and made this material more useful for photographic studies, even though

thicknesses greater than 25 mm were not readily available.

2.4.1 Experimental Configurations for Photographic Studies. Representative

configurations for photographic observations of penetration are shown in Figures 5 and 6.

The earliest tests were conducted with back lighting as shown in Figure 5. A plastic Fresnel

lens imaged the light from an exploding wire into the aperture of a high-speed framing

camera. The target was located close to the Fresncl lens and consisted of a glass block,

backed by steel, with a cover of polymethylmethacry late (f MMA). The PMMA cover was

usually 25 mm thick and shielded the glass from debris that might precede the jet.

Penetration in the PMMA was supersonic, allowing the jet to arrive at the glass before other

disturbances that could produce damage. Targets commonly had a 102-mm-square cross

section. Waves reflected from the lateral boundary never produced troublesome surface

damage and did not return to the axis of penetration before measurements were completed,

JET

I

I PMMA

GLASS

GLASS

GLASS

STEEL

CAMERA3VIEW

Figure 5. Configuration for Photographic Tests With Back Liqhtinq,

9

penetration and made this material more useful for photographic studies, even though

thicknesses greater than 25 mm were not readily available.

2.4.1 Experimental Configurations for prlOtographic Studies. Representative

configurations for photographic observations of penetration are shown in Figures 5 and 6.

The earliest tests were conducted with back lighting as shown in Figure 5. A plastic Fresnel

lens imaged the light from an exploding wire into the aperture of a high-speed framing

camera. The target was located close to the Fresnel lens and consisted of a glass block,

backed by steel, with a cover of polymethylmethacrylate (PMMA). The PMMA cover was

usually 25 mm thick and shielded the glass from debris that might precede the jet.

Penetration in the PMMA was supersonic, allowing the jet to arrive at the glass before other

disturbances that could produce damage. Targets commonly had a 1 02-mm-square cross

section. Waves reflected from the lateral boundary never produced troublesome surface

damage and did not return to the axis of penetration before measurements were completed.

JET

~ FRESNEL PMMA LENS

GLASS

* -< CAMERA

~ GLASS VIEW

GLASS EXPLODING WIRE

STEEL

Figure 5. Configuration for Photographic Tests With Back Lighting.

9

*

JETAXIS

L/ CAMERA

VIEW

* -%---- ;;:):;

JTOP VIEW \ EX&;PL.:lNG

WHITEREFLECTOR/

DIFFUSERJET

SHIELD

GLASS

‘J “

CAMERA

VIEWGLASS

GLASS~ EX&:PL:lNG

STEEL

SIDE VIEW

Figiure 6. Configuration for Photoq raphic Tests With Front Llqhtinq.

10

JET AXIS

~

TOP VIEW

WHITE REFLECTOR!

DIFFUSER JET 1-

PMMA

GLASS

GLASS

GLASS

STEEL

SIDE VIEW

~ CAMERA VIEW

• ~OPAQUE SHIELD

\EXPLOOING WIRE

/S

k~ ~

HIELD

~ CAMERA VIEW

EXPLODING WIRE

Figure 6. Configuration for Photographic Tests With Front Lighting.

10

Damage that limited photographic observations W;IF lt~,-ir:+ct[>ristlc[ally imtiated close to the axis

of penetration at interfaces or imperfection:’ ir~ III(: .:i.::lC Unfortunately, the permanen!ty

densifled region around the penetration patl :!rI.?Wr;iYrf!fractcd the back light and prevcrltcd

critical observations. Consequently, ttle frorll i ,! I II ?I:st conflguratiorl in Figure 6 was

introduced to overcome the refraction proti~l~l, .{ .,.: ~!~xf wittl back Iigtltlng. Front Iigtlting

was providc?d by exploding tungster~ wire:, ~!t ‘ ,A;..i~ : Iliclded frorr~ dirt?ct observation by tt]u

‘}[~ wt:]k, diffust;d back lighting incanlwa A whd(? card at the bock of th[? tnrk~!l ~:r:. :...

acfditiotl to tile strong front lighting, and ttll: ~ ~:. ~~‘:’i was judg~?d to provide the rllo$t

complctc photograpl}lc detail.

Glass targets were photographed durir!!} p , !:i~[] by t)otl] corltlnuouss and partlculatc[j

jots. In all tests to be reported, photograph:; wt.: ~ ,,.,. !.,‘ {~’] ,]t 1 ps intcrv:ds. When tt]e standoff

distance was approximately 140 mm, j[?t bri:~~ . i ur~(’[j tjuring penotratlon in the tt~ick

PMMA cover and p[?netration in the glass wi~L ;.::!:t,;y by Jet s[?grllents or particles. When tllc

standoff distance was approximately 50 mnl, I!!C j~:[ usu;]lly remained continuous throughout

all of the observed penetration into glass.

2.4.2 Jet Penetration Into Fused Quartz I IJ(I;,I 7 shows penetration] tilnc data obtained

by high speed photography during jet penctr;~timl Intl.: [I!onolitllic fused quartz. Jet breakup

occurred during penetration in the PMMA cover. Ttw penetration model generated a

penetration path in agreement with the experirllt’ntat d,~ta when the assigned target resistance

was 11 GPa. After approximately 10 ps of pen[;tr(itltirl into fused quartz, the experimental

data began to deviate slightly from the calculat[xf penetration path. Agreement with the later

data points was achieved by assigning a higl~(?r rcwstance value of 22 GPa. Photographic

measurements ended at approximately 16.3 ps when the penetration front was overtaken and

obscured by trailing fracture.

Flash radiographic tests, reported in Section 2.3, provided a few measurements of the

penetration depth in fused quartz after fracture obscured the penetration front and ended

photographic measurements. In Figure 8, these radiographic data are combined with the

photographic data. The radiographic data on Curve A were obtained from tests with Target A

in Figure 2; the one datum point on Curve B was ot~tainc?d from a test with Target B. For

11

Oamage Olat limited photograp~lic obscrvatlufh W;l~, I .. ll<1rdcteristically initiated close to Hw axis

of penetration (1t interfaces or imperfection~; In til[;lt.l:,c, Unfortun(ltely, trw permanently

densified region (1round the penetr(1tion p;lth ~;tr'Ylqiy rrdractcd th(~ back light (1nd prevC'rltud

critical observations. Consequently, tile frem! : :~i(.d t!~sl configuration in Figure 6 was

introduced to overcome the refraction probl/'il\ Y' '~'" !kd with back lighling. Front ligtlting

was provid(~d by exploding tungsten wirc~;\'\il" "">,, :11Il:lded troln direct observation by tile

camer;l A wtlite card 3t ttw back of the t:Jlq:': ,'r,\\ ,j,'d wl~,lk, diffuSL~d back ligtlting in

additioll to tlw strong front lighting, and Uli~ ., t 'hi'] was judged to provide thu most

complete ptlOtographlc detail.

Glass targets were pl1otograptlcd durirH) 1,,1, HI II tly twill COlltlrllJOLJS c!rld paltlculatl:d

jets. In all tests to be reported, ptlOtograptl:; liV,: l' tdk'll ,It 1 ps intervals. Wilen Hw stzllldoff

distance W(1S approximately 140 mm, jut brl;'~.' if' (H,UIIL'rJ during pmwtration in tlw thick

PMMA cover and p(~netration in ttle glass Wej' t 'fib Y by In! segments or particles. Wt,cn ttH!

standoff distance was approximately 50 mill, \! !L~ 1(:1 lIsuzllly remained continuous ttHoughout

all of the observed penetration into glass.

2.4.2 Jet Penetration Into Fused Quartz f l'lll!l' 7 shows penetration time data obtaim~d

by high speed photography during jet penetration In!,) 11!orlolitilic fused quartz. Jet breakup

occurred during penetration in the PMMA COVl:r. Tile penetration model generated a

penetration path in agreement with the experinwntal dolta wtwn the assigned target resistance

was 11 GPa. After approximately 10 ps of pcnl~tr<ltIOf1 into fused quartz, the experimental

data began to deviate slightly from the calculalt~d penetration pattl. Agreement with the laler

data pOints was achieved by assigning a higtll~r rW;lstClnce value of 22 GPa. Photographic

measurements ended at approximately 16.3 ~IS wtlcn tile penetration front was overtaken and

obscured by trailing fracture.

Flash radiographic tests, reported in Section 2.3, provided a few measurements of the

penetration depth in fused quartz after fracture obscured the penetration front and ended

photographiC measurements. In Figure 8, these radiographic data are combined with the

photographic data. The radiographic data on Curve A were obtained from tests with Target A

in Figure 2; the one datum point on Curve B WClS ot1tained from a test with Target B. For

11

T1

IT

11

I

NN

\\&

\f

\\‘t\.

\’c.~

U-)

‘...\Ld

‘\:

‘k\

“\\~

‘..,

,J

UJLU

‘N

OllV

&j13N

3d

70

60

E E 50

z 0 f-- 40 <1

--'- 0::: rv

f--W Z 30 w CL /

/

20

10

.)"

-~----~~--------"-.,----------~

~R=II

10

TiME,fL S

/.o",~ /.d#.' ~R=22

//

FUSED QUARTZ --- - -

PMMA

15 20

EE

zo

t=21-LdzuCl_

5(

c

FUSED Q.UARTZ .._.. . . . .STEEL

001 I

50 100 150

Figure 8.

TIME , /LS

Combined Radiographic and Photographic Data for Jet Penetration Into FusedQuartz.

E E

z

150

o 100 I-« 0::: I­W Z W 0..

50

---c

_______ 8

-...(')--A

__ ~_USED Q_l)ARTZ STEEL

°0~------------5~0~------------1~0-0------------~150

TIME, fLs

Figure 8. Combined Radiographic and Photographic Data for Jet Penetration Into Fused Quartz.

13

refererlce, Curve C IS an extrapolation of data at the beginning of penetrtition in Figure 7,

wtlcre the assigned target resistance was 11 GPA Radiographic data con flrn]cd a subst:ultlal

increase in target resistance during jet penetration into fused quartz, in agreement with !hc

minimal photograph evtdence for such an increase. Target A became r~lore resistant to

penetration than Tar’get B. TIICSC target configurations provided stmilar lateral confine[~lcr]l for

the fused quartz core, but Target A provided better confinement by tt]e frorlt steel plat{?. An

cxarnination of re~ovured targets revealed that as the steel plate In Target A W:N pcnutrat(;d.

radial deformation caused engravcment into tile surrounding alul II Inu ITl, keeping It in plac~?. In

colmp; ~rison, the steel plate at the front of Target B bulged outward, reducing tt)c con finerllcnt

of core material.

In Figure 9, penetration into fused quartz IS compared with punctuation Into crystalline

quartz, The curve ior fused quartz (FQ) is based on both the pl]otograpl]iu data and tllLI

radiographic data obtwn(.:ci wltll Target A. Tflc curve for crystalline quartz (~(l) IS based

solely or) one ra{~lc(gr;~pt~lc [r]~’asur err lent wittl T,arget A. By assigrllng crys!:llllrle quartz a

target resistance of 14 GPa, the model provided close agreement with both ttl[: radlograpt]c

datun) point ar-d the final deptt] of p[,?netration measured in th[: recovered targt?t. This

agreement suggested that cavity closure, found in the recovered target, dld not occur quickly

enough to have a slgnlflcant In flucr]ce on jet penetratiorl into cryst:~lline quartz In Flgurc 9 lt

is apparent ttlzt fused quartz. early irl tt~c pcl]etratlorl, becomes ,] f)lorc r[::;l:;!;irlt t~]rgt:t

material than crystalline quartz

Although Illgt] :;pccd pt~otograptly was able to provide penetration !irnc data for fused

quartz, tl]c r,pd propagation] of trailrng fracture alw;?ys prevented obs[; rva!lorls of tt)e

penetration path IP the rl:glon bc!hnd tile pcflctrallon front wtlcre d[.:twls were poorly duflr]cd in

fla:,tl radiograph):, a(Ici wtlcrt; lrlforrl);~tior) was neudcd to cx.~)l:]ln t!]c incru,~:;u III t:irgct

resistar]ce durirlq jut pcnetr; itlor) Borosil/cat~; glass allowed r])orc of tllc pl’nctratlor~ path to

be observed, Lut ptlotograplls by Zcrnow and Hauvcr (1!355) arid by Pugt] et ~1. (1951)

$;t]owcd a grcatur i{~r]gtll of the penetration path than could be observed wltl~ borosllicate

glass. The greatest observed path Icnglh implies the lowest rate of fracture propagation

wtlictl would nlahe suet] a glass most suitable for photograptllc observ~~tions The g[aSS USUd

by Zernow anc Hauver was recently analyzed and Identified as a sodallnlc composition

14

relen.mce, Curve C IS 3rl extrLlpolatlon of data at the beginning of perwtr(Jtion in Figure 7,

where the assigned target resist3nce was 11 GPA Radiographic dat3 conflrrlll;d a substantial

increase in target resistance during jet penetration into fused qU3rtz, in agreement with trw

minimal photograprl1c evidence for such an increase. Target A became morc resistant to

penetration ttlan T~lrget 8. These target configurations provided similor loteral confinerllL'f1t for

the fused quartz core, but T;:1(get A provided better confinement by tt18 frollt str;el plate. An

exarnination of recovured torgets revealed thdt as the steel pldte in Target A was perwtratc;d,

radiol deformotion caused engravelTlent into trle surrounding aluminulll, kc(;ping It ill placl' In

comparison, the stuci platu dt ttle front of Tdrget B bulged outwdrd, reducing ttlt: confirWl111;nt

of core mdtericll.

In Figure 9, pr.:rwtration into fused qUdrtz IS cornp;m:d with pc:netration Into crystalline

quartz. Tr18 curve tor fUSI:d quartz (FO) is based on bottl trw pflotograprlic.; dal3 and ttl(;

radiograpfllc data obtalrwd Wlttl Target A. Trw curve for crystalline quartz (CO) is bZ1sr::d

soltJIy on one rddl(X]faprllc rnuaSUWrTI(:;nt Wiltl T;1(get A By assiCJfling cry~;talllllC quartz a

target resistance of 14 GPa, the model provided close agreement with bOttl ttll: radiogrdptllc

datum point al',d ttw final depttl of p(;netratioll measured in trw r()cover(Jd tarot:! This

agreernent suggested thZ1t cavity closure, found in the recovered target, diu not occur qUickly

enough to have a ~;Ignrficant Illflueflcu on jet penetratioll into crystalline quartz In Flgur(; ~), It

is apparent ttl;;! fu~;ed quartz, early In tile fJl'llctratiorl, becornr:s d rnorl; 1(~:;I:;LHlt tLHgl.:t

rna te rial ttl an cry:" tilll i ne qu artz.

AltrlOugrl high ;;pecd ptlOtography was able to provide penetrZ1tion tilile dZlta for fused

quartz, the lapld propagatiorl of trailing fracture always prevented observatlolls of ttle

penetration path In the rl:gion berllrld ttle pc:nutratlon front Wflr;ru de:taiis WUrl: poorly dufincd in

flash r(]dlogra~fls and wlll:rl: Irllorlnation was rwc:dud to expl;Jln ttlC irlcrudSu III Urg(;t

resistance ciUrlrl~] Jut penelldllon Oorosilicdtl! glass allowL:d I110le of ttll: p,:rletrzltloll pattl to

be obsl:rved, t,ut ptlotograplls by b;rrlOw dnd Hauvu( (1955) zHid by F)Ugtl et al. (1951)

c;rlOwcd a gruatur Icmgltl of ttw punetration patti than could be observed wltll borOSilicate

glJSS The grl'atl;st observed path length implies the lowest rate of fracture propZ1gation

Wilictl would maku sUetl a glass most suit3ble for photographiC ooserveltiolls TrlO glass usud

by Zernow anc Hauver was recently analyzed and Identified 3S 3 sodallfllC composition

14

E 10E.

1-aCK

LIJ 5(n

c

1 1

I

CQ

-- 0 --FQ---~-/“.-

QUARTZ—..STEEL

. . . --—— .

I

)I

50 100 1!TIME , /AS

Figure 9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FQ)and Crystalline Quartz (CQ).

15

150~------------~--------------~--------------~

EIOO E

z o ~ 0::: ~ W Z w 50 a..

I I

/

/ /

/

,0 , /

/

50 TIME, f-Ls

CQ

_-0-- FQ

QUARTZ ----

STEEL

100 150

Figure 9. Comparison of Penetration-Time Data for Jet Penetration Into Fused Quartz (FO) and Crystalline Ouartz (CO).

15

without the ferric-ion impurity that commonly imparts a green color to thick window glass. The

glass used by Pugtl et al. was identified as commercial soda-lime. Photographic

measurements of penetration-time were conducted with both types of soda lime glass.

2.4.3 Jet Penetration Into Soda-Lime Glass, Most of the photographic studies with

soda lime glass were conducted with front lighting, and the basic configuration IS stlown in

Figure 6. The standoff in most tests was approximately 140 mm, and in these tests the glass

was penetrated by a partlculated jet. Two tests were conducted with a shorter standoff of

approximately 50 mm, and in these tests the jet was continuous throughout nlost of ttlc

photographic sequence. One test was conducted with the soda lime glass without ferric Iorl

impurity. Tt~is test was of interest because the glass was monolithic and cor]!:]lrlud st)lall

bubbles. All other tests were conducted with commercial soda Iirne plate whIct) had (i

thickness of 25 mrm Tests with a continuous jet will be described first

Flgur[> 10 shows sequential photographs of a continuous jet pcnctratlng 25 rl~rn tlllch

plates of soda Ii[llr- glass. Photographs were at 1 ps intervals and were t;~ken will] s,tror]g

front Ilghtlng and weak back hghting. These photographs show the boundary of tilt:

penetratiorl path, tllc per[nar]cntly denslfled volun~c surrou[ldlrlg ttlc pt?r]t;tr,]tl[[~ p,ittl, ttl~

trwling fr:lctlurc :~r’d Il]e fracture inltl;]t~.:d at ;I borldcd intcrf, icc hutwc[’rl [; I,V-I ;)I,III;: TI:,)

penctr; ~tion pat}) IS observed to op[:r] and t!l[:n p~rtially CIOSC Slr)c[> ~!~~-![(’ l.(’(’!)r: t)l.’t~)r(? [tl(

surrounding glass undergoes brittle fwlure, It IS concludud tl~at closure IS prir~~,irlly i[so(witcd

with recovery from high pressures near the pcnctratlorl front. Tf]c boundary of ttle

permanently dcnslfied volume, whict] IS initially at the yield stress, displays slrqtlt n(;cklr]g as a

result of elastic rccovcry. The boundary Iaycr of the penetratlor~ pattl IS tllc or]ly p,]rt ot Itlc

targ[:t that is recovered intact Surrourld[ng !argct material foils Into p;~rtlclt;s w!)IcI) ,Irc

disp(;rc(-+d by ttlc blast, wtIIlc nl;]tcrioi in the pcn[?tratlotl paf!l is higtlly ~IIot}ilc tirlcl t):ti~I~L:; w;

the target fails. TIIe heated boundary layer is sufficiently plastlc to resist brlttlc f,]ilurc :~IId

survives with recognizable features. This boundary layer was found to have :1 tl~lckr]c:;s of

approximately 1 mm.

Figure 11 shows penetration fime data for the test pictured in Figure 10. All of tt~e

experimental data are In close agreement with a curve generated by the penetration Illodcl

16

without the ferric-ion impurity that commonly imparts a green color to thick window glass. Tr10

glass used by Pugh et al was identified as commercial soda lime. Photographic

measurements of penetration time were conducted with both types of soda lime glass.

2.4.3 Jet Penetration Into Soda Lime Glass. Most of the photograpr1ic studies with

soda lime glass were conducted with front lighting, and the basic configuration is shown in

Figure 6. The standoff in most tests was approximately 140 mm, and in Hlese tests ttw glLlSS

was penetrated by a particulated jet. Two tests were conducted with a shorter standoff of

approximately 50 mm, and in these tests the jet was continuous throughout most of tile

photographic sequence. One test was conducted with the soda lime glass without ferric ion

impurity Ttlis test was of interest because the glass was monolithic and con\;lIflL:u :~1llall

bubbles. All other tests were conducted with commercial soda lime plate wtllch tlad a

thickness of 25 mm. Tests with a continuous Jet will be described first.

Figure 10 shows sequential photographs of a continuous jet penetr3ting 25 1111ll tllick

plates of soda lillll glass Photographs were at 1 ps intervals and were takell with strollC]

front ligllting and weak back lighting TllOse photograprls show ttlC boulld~1ry oj till;

penetration path, tll(~ permanently densifled volunw surroullding tlw Pl;lll:trdtloll fJdtll till;

trailing fr;Jcturc:, dnd tiw fracture illitiilt'.:d at a bondl:d illtcrL1Ct; hetvvl;(;ll CJI;t:~:~ pl,lk:: Ti:!'

perwtrdtiorl path IS observl.:d to opell and tiH;n partially clos(; Since clo:',:JrI' C(lJr:: h,·tcHI; ttl(:

surrounding glass undergoes brittle failure, It is concluded ttlat closure IS prilll,trlly d';SOll,lku

with recovery from 11igh pressures rWilr trw penetratlorl front. The bourldary of ttw

permanently dcnsified volume, which IS initially ilt trw yield stress, displays SllQllt Ill~cklf1CJ as a

result of elastic rf.:covcry. Ttw boundary layur of tlie pcnetr;]tlon patll IS the Gilly pdr! of HIL:

t1rg(~t Hlat IS recovered Intact Surroulldlng t;lrget rTlJteriill fCliis Into p;Jrtlclc's wlliell ,H;.'

disp(;rsf:d t)y til(': blast, willie lTlatenal in tllU p(;lwtratioll patti IS lligtlly l!lobile; ,Hid (':'CclrW,; ;):~

trle target fails Tile Iwated boundary layer is sufticiently plastiC to resist brittle fdilure ZUlU

survives witli recognizable features. This boundary layer was found to have (j tillcklle~;:~ of

approximately 1 mm.

Figure 11 S~10WS penetration time data for the test pictured in Figure 10 All of tile

experimental data are in close agreement with a curve generated by the perwtration l110del

16

;;~~~ ,

.~!S .\ ~.:.. : .... f •

t

u

<tl I E E o

I J

17

l -VJ

~ -Q) ..., VJ :::J o :::J ,~ C o

(!) U

.0 c .Q 1ii ~ Q) c Q)

c.. c 'C :::J o

LL. ~ VJ VJ ro (5 Q)

E ::; tb 'lJ o

(J)

a

1I

II

II

II

#I

-lA

af-

00

vw

u)In

em

%

UJU

J‘

NO

llVM

13N3d

u

1-

18

70

60

E 50 E

z o 40

~ a::

...... ~ (X) w 30

Z w a...

20

10

5 10

TIME , J-LS

15

SLG-2

SLG-I

PMMA

Figure 11. Penetration-Time Data for the Jet Penetration Shown in Figure 10.

----

20

with R = 7 GPa. There is no evidence of an increase in target resistance such as detected

with fused quartz in Figure 7. Jet breakup, based on free-flight observations, is indicated on

the penetration path and should have occurred at the end of the photographic sequence in

Figure 10. Frame H in Figure 10 does show an irregularity at the end of the penetration path

that resembles penetration by a jet particle. Later, similar features will be observed during

penetration by a jet that is definitely particulate.

The target configuration in Figure 6 was modified for a second penetration test with a

continuous jet. Thickness of the PMMA cover was reduced to 3.2 mm and a 25-mm thickness

of steel was added at the front. A hole, 4.8 mm in diameter, was drilled through the steel to

admit the jet. It was anticipated that the confinement provided by this steel plate would

enhance path closure close to the PMMA-glass interface. Sequential photographs from this

test are shown in Figure 12. When compared with the photographs in Figure 10, the

penetration path in this test is highly asymmetrical, with protrusions and regions of intense

self-luminosity that were not observed in the preceding test with a continuous jet. These

features suggest a greater interaction between the jet and the glass target.

Figure 13 shows penetration-time data from the second test with a continuous jet. Data

during the first 9 ps of penetration into glass were in agreement with a curve generated by

assigning a target resistance of 7 GPa. However, the target resistance then increased

abruptly and a value of 40 GPa was necessary to produce agreement with the final three data

points. Jet breakup should have occurred after the final point.

Photographs from both tests with a continuous jet were measured to determine how the

diameter of the penetration path, including the boundary layer, varied with time. Path

diameters were measured at approximately the same location in each test, and the locations

are indicated by arrows in Figures 10 and 12. In Figure 14, the path diameters are plotted as

a function of time. In the first test, which had a highly symmetrical penetration path, the path

opened to its maximum diameter in 2 w and then partially closed before fracture obscured the

measurement location. In the second test, the diameter began to deviate from the trend of

the first test at 2–3 p.s, and reopening was clearly established at 5 ps. It is assumed that this

resulted from an interaction with elements of the jet behind the penetration front. In Figure 15,

the penetration path from Figure 13 is replotted along with a path for the jet element that

19

with R = 7 GPa. There is no evidence of an increase in target resistance such as detected

with fused quartz in Figure 7. Jet breakup, based on free-flight observations, is indicated on

the penetration path and should have occurred at the end of the photographic sequence in

Figure 10. Frame H in Figure 10 does show an irregularity at the end of the penetration path

that resembles penetration by a jet particle. Later, similar features will be observed during

penetration by a jet that is definitely particulated.

The target configuration in Figure 6 was modified for a second penetration test with a

continuous jet. Thickness of the PMMA cover was reduced to 3.2 mm and a 25-mm thickness

of steel was added at the front. A hole, 4.8 mm in diameter, was drilled through the steel to

admit the jet. It was anticipated that the confinement provided by this steel plate would

enhance path closure close to the PMMA-glass interface. Sequential photographs from this

test are shown in Figure 12. When compared with the photographs in Figure 10, the

penetration path in this test is highly asymmetrical, with protrusions and regions of intense

self-luminosity that were not observed in the preceding test with a continuous jet. These

features suggest a greater interaction between the jet and the glass target.

Figure 13 shows penetration-time data from the second test with a continuous jet. Data

during the first 9 JlS of penetration into glass were in agreement with a curve generated by

assigning a target resistance of 7 GPa. However, the target resistance then increased

abruptly and a value of 40 GPa was necessary to produce agreement with the final three data

pOints. Jet breakup should have occurred after the final point.

Photographs from both tests with a continuous jet were measured to determine how the

diameter of the penetration path, including the boundary layer, varied with time. Path

diameters were measured at approximately the same location in each test, and the locations

are indicated by arrows in Figures 10 and 12. In Figure 14, the path diameters are plotted as

a function of time. In the first test, which had a highly symmetrical penetration path, the path

opened to its maximum diameter in 2 JlS and then partially closed before fracture obscured the

measurement location. In the second test, the diameter began to deviate from the trend of

the first test at 2-3 JlS, and reopening was clearly established at 5 Ils. It is assumed that this

resulted from an interaction with elements of the jet behind the penetration front. In Figure 15,

the penetration path from Figure 13 is replotted along with a path for the jet element that

19

C\J -u u. '" Q)

f-

a; --,

'" ::;)

0 ::;) c "" c 0 U

'" .0 c 0

~ ~

a;

"l c

CD Q)

a..

~

'" f-

'" '" '" (3 Q)

E :::i ,

'" "0 0

<l Cl (f)

'" '0

f '" .r:

'" E ~

E 0

Q 0

1 .r: a..

C\J

Q) ~

::;)

Ol u::

20

II

3.-g1-

21

I\) .......

60~------~------------~--------------~------------~----,

50

40 E E

.. 30 Z 0 r <{ 20 a:: r w z w 10 a..

o

-10

-_.-----

~-

~.

o 5

~

, /,' ,BREAKUP " ---,- -_._-

.~FRACTURE ~ V=1960m/s

SLG-2

SLG-I PMMA

STEEL ----

(DRILLED TO ADMIT THE JET)

10 15

TIME, lis

Figure 13. Penetration-Time Data for the Jet Penetration Shown in Figure 12.

t I I 1 1 I 1

6 -

#

t

00I

I 2 3 4 5

-\\

“’’A-...---A- 1

A 25 mm PMMA COVERo DRILLED STEEL COVER

1

6

TIME , ~S

Figure 14. Path Diameter as a Function of Time (Continuous Jets}.

arrives at the transition point where the target resistance increases. This jet element reached

the location of diameter measurements approximately 2.3 p after the tip. This time is in

general agreement with the 2=3 ps time at which the curves begin to deviate in Figure 14.

Two factors probably contributed to features of the penetration path in Figure 14. First,

the presence of a thick steel cover provided confinement which aided path closure close to

the glass surface. Second, earlier studies (Zernow et al. 1975; Meyer 1987) showed that

reflected debris particles can disrupt a jet as it passes through a tubular opening. The

continuous jet in the second test was undoubtedly disrupted while passing through the 4.8-mm

diameter hole drilled through the steel cover, and the disruptions caused early interactions

between the jet and the closing penetration path. Protrusions and regions of intense

luminosity in Figure 12 are evidence of such interactions.

Photographic tests were also conducted to determine how a particulate jet interacts with

a target of soda-lime glass. Figure 16 shows a sequence

22

of photographs taken at 1–ps

E E ..

a:: w r-w ~ <{ -£:)

J:

~ a.:

6

4

°0

....... ...... ...... ..... 6,..

-..- .... _- .. ll,..

6. 25 mm PMMA COVER o DRILLED STEEL COVER

234

TIME , !-,-5

5

Figure 14. Path Diameter as a Function of Time (Continuous Jets).

6

arrives at the transition point where the target resistance increases. This jet element reached

the location of diameter measurements approximately 2.3 I1s after the tip. This time is in

general agreement with the 2-3 J..LS time at which the curves begin to deviate in Figure 14.

Two factors probably contributed to features of the penetration path in Figure 14. First,

the presence of a thick steel cover provided confinement which aided path closure close to

the glass surface. Second, earlier studies (Zernow et al. 1975; Meyer 1987) showed that

reflected debris particles can disrupt a jet as it passes through a tubular opening. The

continuous jet in the second test was undoubtedly disrupted while passing through the 4.8-mm

diameter hole drilled through the steel cover, and the disruptions caused early interactions

between the jet and the closing penetration path. Protrusions and regions of intense

luminosity in Figure 12 are evidence of such interactions.

Photographic tests were also conducted to determine how a particulated jet interacts with

a target of soda-lime glass. Figure 16 shows a sequence of photographs taken at 1-I1S

22

5(

4[

3(

2(

Ic

c

-Ic

-20

I

4/

/e//0

//

TRANSITION

R=7

/

J-2.3ps ,, MEASUREMENT OF

/

PATH DIAMETER

//’

A SODA-LIME GLASS\\

,.

/

PMMA (DRILLED TOADMIT THE JET)

,’

/

1 1 I 1 1nI. —

4 10 12

TIME , @

Figure 15. Penetration-Time Curves From Fiqure 13, Includinq a Path for the Jet ElementThat Arrives at the Transition Point.

23

50

40

E 30 E

8 20 r-« 0:: r- 10 w Z w a...

o

-10

-20

o

/

2

'" '" '"

'" '" '"

..... ..... -'" '" '"

TRANSITION~ '" " ~R=40

, ,

23ILS~MEASUREMENT OF . j.' PATH DIAMETER

" SODA- LIME GLASS

PMMA

4 6 8 TIME, fLS

STEEL (DRILLED TO

ADMIT THE JET)

10 12

Figure 15. Penetration-Time Curves From Figure 13, Including a Path for the Jet Element That Arrives at the Transition Point.

23

ll..

-(/) Q)

f--Q) --, "0 Q)

Iii :::> u t ell [L

ell

D c 0

~ ~

w a; c Q) [L

~

ell f-(/) (/) ell

c:?

t Q)

E :.::; , ell "0 0

Cf)

ell

<{ Cl 0 (/) .t::

I ell ~

II.~ ,-1i., .';'. ." • I f • . , -_.

i 0 -0 .t:: [L

E E <D 0 1

1 Q) ~

:::> Cl u:::

t

24

intervals during penetration by a particulate jet, The basic features are similar to those

observed with a continuous jet in Figure 10. Photographs show the boundary of the

penetration path, the permanently densified volume surrounding the penetration path, the

trailing fracture, and the fracture initiated at a bonded interface between glass plates.

However, these photographs show an undulating penetration path which opens and partially

closes with the impact of each successive jet particle. Intense self-luminosity is associated

with each impact. Reopening of the penetration path after partial closure is evident at the

neck region, which is indicated by arrows in Frames E and F. Path diameters were measured

both at the neck region and at the maximum which is indicated by arrows in Frame D.

Diameters at both locations are plotted against time in Figure 17. At the neck location,

reopening of the penetration path begins approximately 3.3 VS after the initial opening. This

reopening is attributed to the interaction with a jet particle as it passes the location of the

measurement in Frame F.

Figure 18 shows penetration-time data for the test pictured in Figure 16. As in the case of

a continuous jet, the initial part of penetration into soda-lime glass is described by the model

using an assigned target resistance of 7 GPa. At 16.6 VS, the final datum point is displaced

significantly below the extrapolated path for R = 7 GPa, providing minimal evidence of an

increase in target resistance. The jet element arriving at the apparent transition point passes

the neck location 3.1 VS after the penetration front, in close agreement with the reopening time

in Figure 17. This agreement increases confidence in the final datum point of Figure 18. With

the

the

highly symmetrical penetration path in Figure 16, reopening at the neck region is clearly

first evidence of an interaction with jet elements behind the penetration front.

The penetration pictured in Figure 19 was obtained with a test configuration nearly

identical to the one for the preceding test. However, this second test with a particulate jet

used only front lighting. Without back lighting, the permanently densified region cannot be

seen. In this test, the penetration path lacks the symmetry observed in the preceding test.

There are numerous protrusions and regions of intense self-luminosity that indicate a strong

interaction between the target and jet elements behind the penetration front. This different

behavior is attributed to round-to-round variations of the shaped charge. The penetration-time

data for this test are plotted in Figure 20. As in preceding tests with soda-lime glass, the first

25

intervals during penetration by a particulated jet. The basic features are similar to those

observed with a continuous jet in Figure 10. Photographs show the boundary of the

penetration path, the permanently densified volume surrounding the penetration path, the

trailing fracture, and the fracture initiated at a bonded interface between glass plates.

However, these photographs show an undulating penetration path which opens and partially

closes with the impact of each successive jet particle. Intense self-luminosity is associated

with each impact. Reopening of the penetration path after partial closure is evident at the

neck region, which is indicated by arrows in Frames E and F. Path diameters were measured

both at the neck region and at the maximum which is indicated by arrows in Frame D.

Diameters at both locations are plotted against time in Figure 17. At the neck location,

reopening of the penetration path begins approximately 3.3 IlS after the initial opening. This

reopening is attributed to the interaction with a jet particle as it passes the location of the

measurement in Frame F.

Figure 18 shows penetration-time data for the test pictured in Figure 16. As in the case of

a continuous jet, the initial part of penetration into soda-lime glass is described by the model

using an assigned target resistance of 7 GPa. At 16.6 Ils, the final datum pOint is displaced

significantly below the extrapolated path for A = 7 GPa, providing minimal evidence of an

increase in target resistance. The jet element arriving at the apparent transition pOint passes

the neck location 3.1 Ils after the penetration front, in close agreement with the reopening time

in Figure 17. This agreement increases confidence in the final datum point of Figure 18. With

the highly symmetrical penetration path in Figure 16, reopening at the neck region is clearly

the first evidence of an interaction with jet elements behind the penetration front.

The penetration pictured in Figure 19 was obtained with a test configuration nearly

identical to the one for the preceding test. However, this second test with a particulated jet

used only front lighting. Without back lighting, the permanently densified region cannot be

seen. In this test, the penetration path lacks the symmetry observed in the preceding test.

There are numerous protrusions and regions of intense self-luminosity that indicate a strong

interaction between the target and jet elements behind the penetration front. This different

behavior is attributed to round-to-round variations of the shaped charge. The penetration-time

data for this test are plotted in Figure 20. As in preceding tests with soda-lime glass, the first

25

1 I I I 1 I

6 -

/“ o-\~..0---”

A MAXIMUM LOCATION

o MINIMUM (NECK) LOCATION

o! 1 1 I 1 I 1 Iu

Figure 17.

I 2 3 4 5 6

TIME , ~S

Path Diameter as a Function of Time (Particulate Jet}.

part of penetration is described by the model using a target resistance of 7 GPa. However,

after approximately 9 VS of penetration into the glass, there is a pronounced deviation, and

later data can be described only by assigning a target resistance of 80 GPa. This large

increase in resistance must follow directly from the strong photographic evidence of jet-target

interactions behind the penetration front.

Photographs from a third test with a particulate jet are shown in Figure 21. Only back

lighting was used for this test. Increases in the index of refraction within permanently

densified glass, as shown by measurements of Arndt, Hornemann, and Muller (1971), cause

strong refraction of the back light and obscure detail behind the penetration front. Without

multiple shock waves, visible in the original photographs, it would not be obvious that

penetration was by a particulate jet. Refraction also obscures features of the penetration

path that provide evidence of target interactions with jet elements behind the penetration front.

However, the penetration-time data from this test, shown in Figure 22, clearly indicate that

such interactions must have occurred. The initial part of penetration into soda-lime glass is

again described by the model with R = 7 GPa. However, the point at 13.7 ~s (9.3 ps into the

26

~ 6 .. a:: w t--W ~ « -Cl

::r: t--~ 00

A MAXIMUM LOCATION o MINIMUM (NECK) LOCATION

234

TIME, fLs

5

Figure 17. Path Diameter as a Function of Time (Particulated Jet).

6

part of penetration is described by the model using a target resistance of 7 GPa. However,

after approximately 9 Ils of penetration into the glass, there is a pronounced deviation, and

later data can be described only by assigning a target resistance of 80 GPa. This large

increase in resistance must follow directly from the strong photographic evidence of jet-target

interactions behind the penetration front.

Photographs from a third test with a particulated jet are shown in Figure 21. Only back

lighting was used for this test. Increases in the index of refraction within permanently

densified glass, as shown by measurements of Arndt, Hornemann, and Muller (1971), cause

strong refraction of the back light and obscure detail behind the penetration front. Without

multiple shock waves, visible in the original photographs, it would not be obvious that

penetration was by a particulated jet. Refraction also obscures features of the penetration

path that provide evidence of target interactions with jet elements behind the penetration front.

However, the penetration-time data from this test, shown in Figure 22, clearly indicate that

such interactions must have occurred. The initial part of penetration into soda-lime glass is

again described by the model with R = 7 GPa. However, the point at 13.7 IlS (9.3 IlS into the

26

II

I1

II

I

n

m,

ml

Il’.

I

8I,II

4II

;i

..

*

I*

\●

✎

✼✎

✍

t-

UJU

J‘

NO

llVH

13N3d

27

80

70

60

E E

.. 50

z 0 I-- 40 « a:::

I\) I--....., W

Z 30 w a..

20

10

------

.'

j /

5

.'

/ .' /

/

10

TIME , fLS

15

SLG-3

. _.' 0

SLG-2 --------

SLG-I

PMMA

Figure 18. Penetration-Time Data for the Jet Penetration Shown in Figure 16.

20

l r w

28

(\J

en Q)

I-

m -, "0 Q)

~ :::l ()

t ro

Cl. ro

.0 c 0 ~ ro ~ m c Q)

Cl.

VJ VJ ro a Q)

E ::::; cb "0 o (/)

o o .c Cl.

J

1

70

10

5 10

TIME, fLs 15

Figure 20. Penetration-Time Data for the Jet Penetration Shown in Figure 19.

20

~

co I-III III CO

i3 Q)

E :::i cb "0 0 (f)

CO -0 III £:

CO ~

0 -0 £: a. "0 Q)

E :::i

f , -'" (.) E CO E (]) 0

i ~

C\J Q) ~

:J Ol

IT:

30

—

lulu‘

NO

llVU

13N3de.> .....

80

E E SLG-2 ..

.. 50 ~.. ._--~ISODAMP-I z

0 I-<{ 0:: l-W Z w a..

40

30 SLG-I PMMA

20

°0~----------~5~------------10L-------------IL5------------~20

TIME, fLs

Figure 22. Penetration-Time Data for the Jet Penetration Shown in Figure 21.

glass) has deviated from the initial path, and over the next 4 p.s the target resistance

increases to 70 GPa. The presence of Isodamp between the glass plates in this test did not

obviously influence the resistance to penetration, but it apparently delayed interface failure to

provide an additional 2 WSfor observations.

Monolithic soda-lime glass, without ferric-ion impurity, was used for the last photographic

test to be reported. Consecutive frames from this fourth test with a particulate jet are shown

in Figure 23. Strong interactions are indicated by the extremely irregular profile of the

penetration path, and irregularities tend to mask the particle nature of penetration. Periodic

emissions of light are the strongest evidence of particle impacts. Although this glass was

monolithic and offered no interfaces where fracture could be initiated, it did contain many

small bubbles which served as failure sites. Failure was not initiated by the impact shock, but

instead it was observed to occur when a bubble encountered the boundary of permanently

densified glass. Failure at bubbles occurs in Frame C, forward of the penetration path, and in

Frames D–F, where failure sites developed at both the left and right of the penetration path.

Penetration-time data for the test with monolithic soda-lime glass are shown in Figure 24.

The initial part of penetration into the glass is described by the model with R = 8 GPa. This

value is higher than the initial resistance in soda-lime plate used in other tests. The velocity

of trailing fracture was also higher (2,260 m/s, compared to 1,960 m/s for soda-lime plate). In

this test, the target resistance deviated to higher values after only 6 w of penetration into the

glass. However, the higher values of target resistance were consistent with values

determined in tests with soda-lime plate. Failure at bubble sites may have altered the closure

rate in this monolithic glass, causing an early interaction with jet elements behind the

penetration front. Resistance values in other tests with fused quartz and soda-lime plate

never increased earlier than 9 N after the onset of penetration into the glass. Based on this

consistency, it is unlikely that a time as short as 6 ps would have resulted from round-to-round

variation of the shaped charge.

2.5 Examination of Recovered Glass Tarqets. Radiographic targets that contained fused

quartz were recovered and examined. Qualitative visual examinations could not readily

distinguish these targets from recovered targets that contained borosilicate or soda-lime

glasses. Figure 25 shows a fused quartz target that was sectioned to expose the entire

32

glass) has deviated from the initial path, and over the next 4 J.1S the target resistance

increases to 70 GPa. The presence of Isodamp between the glass plates in this test did not

obviously influence the resistance to penetration, but it apparently delayed interface failure to

provide an additional 2 J.1s for observations.

Monolithic soda-lime glass, without ferric-ion impurity, was used for the last photographic

test to be reported. Consecutive frames from this fourth test with a particulated jet are shown

in Figure 23. Strong interactions are indicated by the extremely irregular profile of the

penetration path, and irregularities tend to mask the particle nature of penetration. Periodic

emissions of light are the strongest evidence of particle impacts. Although this glass was

monolithic and offered no interfaces where fracture could be initiated, it did contain many

small bubbles which served as failure sites. Failure was not initiated by the impact shock, but

instead it was observed to occur when a bubble encountered the boundary of permanently

densified glass. Failure at bubbles occurs in Frame C, forward of the penetration path, and in

Frames D-F, where failure sites developed at both the left and right of the penetration path.

Penetration-time data for the test with monolithic soda-lime glass are shown in Figure 24.

The initial part of penetration into the glass is described by the model with R = 8 GPa. This

value is higher than the initial resistance in soda-lime plate used in other tests. The velocity

of trailing fracture was also higher (2,260 mis, compared to 1,960 mls for soda-lime plate). In

this test, the target resistance deviated to higher values after only 6 J.1S of penetration into the

glass. However, the higher values of target resistance were consistent with values

determined in tests with soda-lime plate. Failure at bubble sites may have altered the closure

rate in this monolithic glass, causing an early interaction with jet elements behind the

penetration front. Resistance values in other tests with fused quartz and soda-lime plate

never increased earlier than 9 J.1S after the onset of penetration into the glass. Based on this

consistency, it is unlikely that a time as short as 6 J.1S would have resulted from round-to-round

variation of the shaped charge.

2.5 Examination of Recovered Glass Targets. Radiographic targets that contained fused

quartz were recovered and examined. Qualitative visual examinations could not readily

distinguish these targets from recovered targets that contained borosilicate or soda-lime

glasses. Figure 25 shows a fused quartz target that was sectioned to expose the entire

32

v -oo Cl> I-

u -Cl> --, "0 Cl> -.!!! :::J 0

"" ~ cu Il.. cu

.0 c: a "" CU ~

Q5 c: Cl> Il..

<II w

~

cu I-oo oo cu (5 Cl> E ::J , CU "0 a (J)

.2 ~

Cl "" "0 c: a

f :::2; cu -E a

E a

oo ~

1 cu ~

a -a ~

Il..

C') C\I

Cl> ~

:::J OJ u:

33

.

I10

\r=II

rI

II

1

\

\

m..‘\

)$:\\.\‘.:.\..‘.;...

J&

-11

Inma‘.

\.\\

,\

\.

11

*

11

1I

o0

00

0o

_b

am

em

N0

3...—1-

*“ml

Ulw

bN

OllV

H13N

3d—

34

60

E 50 E

z 40 0

~ w a:: ~ J- 30 w

z W 0-

20

~.

, ".,

,

, , , ,

.,,/-~FRACTURE / V=2260m/s

, ,-'

, ,

MONOLITHIC SLG ---O"'~-- ---------- ----- --

5 10

TIME ~ fLs

PMMA

15

Figure 24. Penetration-Time Data for the Jet Penetration Shown in Figure 23.

20

Figure 25. Fused Quartz Target Sectioned to Expose the Penetration Path Filled With Red Glass.

35

penetration path. Thepath incompletely filled with aporous, opaque, red copper-glass. In

the future, this material will bereferred tosimply as "red glass.'' Astatic x-ray of a recovered

target is shown in Figure 26A, and it reveals that the red glass mntains suspended copper

spheres with diameters up to approximately 2 mm. An SEM micrograph of the red glass is

shown in Figure 266. The large copper sphere at the left in the micrograph has a diameter of

80 ~m, while the smallest spheres approach a diameter of 1 Vm. When a sample of red glass

was examined at the Battelle Pacific Northwest Laboratories, it was concluded that the glass

contained approximately 57. reacted/dissolved copper in addition to suspended copper

spheres. Battelle cited a book by Weyl (1951) and noted the similarity to hematinone, which

is an opaque red glass (glaze) containing suspended copper particles in the submicron range.

Red glass in the penetration path is very fluid just after it is formed and it frequently flows

out of the target. Figure 27 shows red glass which was recovered after it flowed from the

back of a fused quartz target that was perforated by the jet. Although a target may not be

perforated, much of the red glass can also be forced out through the entrance hole if the slug

is allowed to enter. This behavior in a borosilicate glass target is shown in Figure 28.

Figures 28A and 28B show the void produced when the slug displaced red glass from the

penetration path; Figure 28C shows part of the displaced red glass in a trap at the front of the

target; and, Figure 28D shows slug material and red glass near the end of penetration. Radial

cracks in Figure 28D are typical of failure near the end of penetration in targets of both glass

and crystalline quartz. In Figure 28A, it may be noted that temperatures in the penetration

path were high enough to remelt a significant thickness of pulverized glass around the

penetration path (M identifies an area of remelted glass).

The porosity of red glass in the penetration path is tentatively attributed to localized

heating that produces partial vaporization of the jet metal. Cavities in the red glass are

commonly coated with small copper spheres and it is hypothesized that this deposit resulted

from the condensation of copper vapor that initially filled the cavity. It was also observed that

little porosity is produced when glass is penetrated by a steel jet, which should vaporize at a

higher temperature. Penetration paths produced in glass by copper and steel jets are shown

in Figures 29A and 29B, respectively. One glass target penetrated by an aluminum jet was

examined, but the result was ambiguous. As shown in Figures 29C and 29D, material was

ejected from the penetration path and deposited on an overhead plate. Vaporization of the

36

penetration path. The path is completely filled with a porous. opaque. red copper-glass. In

the future. this material will be referred to simply as "red glass." A static x-ray of a recovered

target is shown in Figure 26A. and it reveals that the red glass contains suspended copper

spheres with diameters up to approximately 2 mm. An SEM micrograph of the red glass is

shown in Figure 26B. The large copper sphere at the left in the micrograph has a diameter of

80 ~m. while the smallest spheres approach a diameter of 1 jlm. When a sample of red glass

was examined at the Battelle Pacific Northwest Laboratories. it was concluded that the glass

contained approximately 5% reacted/dissolved copper in addition to suspended copper

spheres. Battelle cited a book by Weyl (1951) and noted the similarity to hematinone. which

is an opaque red glass (glaze) containing suspended copper particles in the submicron range.

Red glass in the penetration path is very fluid just after it is formed and it frequently flows

out of the target. Figure 27 shows red glass which was recovered after it flowed from the

back of a fused quartz target that was perforated by the jet. Although a target may not be

perforated. much of the red glass can also be forced out through the entrance hole if the slug

is allowed to enter. This behavior in a borosilicate glass target is shown in Figure 28.

Figures 28A and 28B show the void produced when the slug displaced red glass from the

penetration path; Figure 28C shows part of the displaced red glass in a trap at the front of the

target; and. Figure 280 shows slug material and red glass near the end of penetration. Radial

cracks in Figure 280 are typical of failure near the end of penetration in targets of both glass

and crystalline quartz. In Figure 28A. it may be noted that temperatures in the penetration

path were high enough to remelt a significant thickness of pulverized glass around the

penetration path (M identifies an area of remelted glass).

The porosity of red glass in the penetration path is tentatively attributed to localized

heating that produces partial vaporization of the jet metal. Cavities in the red glass are

commonly coated with small copper spheres and it is hypothesized that this deposit resulted

from the condensation of copper vapor that initially filled the cavity. It was also observed that

little porosity is produced when glass is penetrated by a steel jet. which should vaporize at a

higher temperature. Penetration paths produced in glass by copper and steel jets are shown

in Figures 29A and 29B. respectively. One glass target penetrated by an aluminum jet was

examined, but the result was ambiguous. As shown in Figures 29C and 290. material was

ejected from the penetration path and deposited on an overhead plate. Vaporization of the

36

c.> .....

., .'. · · • _ _ , "J I , .. • • . .-.""'

" . ...... ~. :~'~ I

"

, , . ~

•• •• HOmm1

• A

Figure 26. (A) Static Radiograph of the Penetration Path in Fused Quartz; (8) SEM Micrograph of Red Glass From the Penetration Path in Fused Quartz.

IIOmm I

Figure 27. Red Glass That Flowed From the Back of a Perforated Fused Quartz Target.

38

t-- 1--- 5mm----I

M

..... - .. 1---5mm----I A B

D

HOmm-i 1-5mm-l

Figure 28. Recovered Target of Borosilicate Glass Showing Red Glass Displaced When the Slug Entered the Target.

39

.j:. o

I4-lmm

• ; -

"

A B Imm

c

-t I-Imm

Figure 29. Glass Targets Penetrated by (A) a Copper Jet, (8) a Steel Jet, and (C) an Aluminum Jet; (D) is a Deposit of Material Ejected From the Penetration Path in (C) .

aluminum jet could have contributed to the ejection, but the penetration model indicated that

aluminum erosion products should travel out of the target at velocities from 700 to 2,500 mls

without a contribution from vaporization.

Evidence indicates that there is a significant interaction between the jet and red glass

which fills the penetration path. Figure 26A, for example, shows a great amount of jet material

suspended as spheres in the red glass. Additional evidence is provided by Figure 30, which

shows a section of the penetration path produced in fused quartz by a small and relatively

slow copper jet. In this test, red glass flowed into spaces between jet particles, with the

exception of a channel that persisted between the two large central particles. These two

particles are tapered, which gives evidence of erosion as they penetrated the red glass.

Interaction with the red glass was strong enough to arrest the forward motion of the entire

sequence of jet particles. The high melt viscosity of fused quartz was probably a factor in the

resistance to particle penetration in this test.

1< 5mm .. I

PENETRATION)

Figure 30. Tapered Jet Particles in Red Glass.

41

2.6 Formation and Role of Red Glass. A recent study by Meade and Jeanloz (1988) was

examined for its possible relationship to behavior during jet penetration into glasses. These

investigators used a Mao-Bell diamond cell to conduct static high-pressure measurements on

a sample of fused quartz mixed with three weight percent ruby of similar particle size. Using

ruby fluorescence, they determined both the average pressure and the pressure gradient

across the sample, which together with the sample thickness provided an approximate

evaluation of the maximum shear stress supported by the sample at pressures between

8.6 and 81 GPa. For convenience, the data of Meade and Jeanloz are plotted in Figure 31.

At an average pressure of 8.6 GPa, they concluded that fused quartz flows plastically, with a

maximum shear stress less than 1 GPa. This conclusion is consistent with the results of

Cagnoux (1981) who concluded from uniaxial strain experiments that a borosilicate glass

exhibited plastic response above the dynamic yield stress. Above 8.6 GPa, the maximum

shear stress measured by Meade and Jeanloz increased. At 26.9 GPa, it attained a value

close to 4.3 GPa, which is approximately the value reported by Proctor, Whitney, and Johnson

(1967) at atmospheric pressure where fused quartz undergoes brittle failure. This result is

consistent with the result by Anan’in, et al. (1974a), who concluded from shock-wave

experiments that fused quartz fails into microblocks separated by interlayers of melt.

Similarly, Kanel, Molodets, and Dremin (1976) concluded from shock wave experiments that

K-8 glass (a borosilicate composition) fails into particles with the subsequent formation of

fused interlayers. Above a pressure of 26.9 GPa, the data of Meade and Jeanloz show that

the maximum shear stress decreases to approximately 0.3 GPa at a pressure of 65 GPa.

Interface pressure during the initial part of jet penetration into fused quartz corresponds to

average pressures where Meade and Jeanloz reported the highest values of shear strength.

This suggests that brittle interface behavior occurs at the penetration front, with the possibility

that jet and target materials mix locally and rapidly produce the red glass. This possibility was

evaluated experimentally by using the technique of Franz and Lawrence (1987) to remove the

rear portion of a copper jet and penetrate a glass target with only a fraction of the jet length.

With a 17 mm length of jet, a visual examination of the recovered target detected only metallic

copper. With a 39 mm length of jet, red glass was clearly beginning to form and accumulate

along the penetration path. It was evident from these tests that red glass does not form

rapidly as a result of brittle behavior at the penetration front. Instead, it tends to form

gradually and accumulate throughout an extended interval during penetration by a copper jet.

42

2.6 Formation and Role of Red Glass. A recent study by Meade and Jeanloz (1988) was

examined for its possible relationship to behavior during jet penetration into glasses. These

investigators used a Mao-Bell diamond cell to conduct static high-pressure measurements on

a sample of fused quartz mixed with three weight percent ruby of similar particle size. Using

ruby fluorescence, they determined both the average pressure and the pressure gradient

across the sample, which together with the sample thickness provided an approximate

evaluation of the maximum shear stress supported by the sample at pressures between

8.6 and 81 GPa. For convenience, the data of Meade and Jeanloz are plotted in Figure 31.

At an average pressure of 8.6 GPa, they concluded that fused quartz flows plastically, with a

maximum shear stress less than 1 GPa. This conclusion is consistent with the results of

Cagnoux (1981) who concluded from uniaxial strain experiments that a borosilicate glass

exhibited plastic response above the dynamic yield stress. Above 8.6 GPa, the maximum

shear stress measured by Meade and Jeanloz increased. At 26.9 GPa, it attained a value

close to 4.3 GPa, which is approximately the value reported by Proctor, Whitney, and Johnson

(1967) at atmospheric pressure where fused quartz undergoes brittle failure. This result is

consistent with the result by Anan'in, et al. (1974a), who concluded from shock-wave

experiments that fused quartz fails into microblocks separated by interlayers of melt.

Similarly, Kanel, Molodets, and Dremin (1976) concluded from shock wave experiments that

K-8 glass (a borosilicate composition) fails into particles with the subsequent formation of

fused interlayers. Above a pressure of 26.9 GPa, the data of Meade and Jeanloz show that

the maximum shear stress decreases to approximately 0.3 GPa at a pressure of 65 GPa.

Interface pressure during the initial part of jet penetration into fused quartz corresponds to

average pressures where Meade and Jeanloz reported the highest values of shear strength.

This suggests that brittle interface behavior occurs at the penetration front, with the possibility

that jet and target materials mix locally and rapidly produce the red glass. This possibility was

evaluated experimentally by using the technique of Franz and Lawrence (1987) to remove the

rear portion of a copper jet and penetrate a glass target with only a fraction of the jet length.

With a 17 mm length of jet. a visual examination of the recovered target detected only metallic

copper. With a 39 mm length of jet, red glass was clearly beginning to form and accumulate

along the penetration path. It was evident from these tests that red glass does not form

rapidly as a result of brittle behavior at the penetration front. Instead, it tends to form

gradually and accumulate throughout an extended interval during penetration by a copper jet.

42

gm=a

●●

●O

\

o

●

✏

●

o/

@

\

●

●

o

43

o 5 MEADE 8& JEANLOZ (1988) a.

(9 .. ® o RECOMPRESSION en '0 en w 0:: t-en 0::: • • ~ <! t.) • W I en 0

• ~ • • • :J

/ ~ 0

X <! ~ •

00 20 40 60 80 AVERAGE PRESSURE , GPo

Figure 31. Data of Meade and Jeanloz.

However, the rate of formation may depend on characteristics of the jefftarget interaction.

Figures 20, 22, and 24 suggest that a glass target may interact more strongly with a jet

broken into discrete particles, and it should be noted that the condition of the jet was different

in the two tests with a short jet length. With a 17 mm length, 75% of the penetration was by a

continuous jet. With a 39 mm length, 99°/0of the penetration was by discrete particles. The

particulate condition of the longer length may have been a factor in the formation of red

glass detected in the target recovered form that experiment.

The photographs in Figures 10 and 16 show fine longitudinal detail which suggests the

termination of radial cracks at the boundary of the penetration path. The appearance was

confirmed when boundary layers were recovered and examined. This observation suggests

that opening and closure are accompanied by brittle failure at the cavity wall, producing glass

particles which mix with material eroded from the jet. The Modified Bernoulli Penetration

Model indicates that erosion products from the jet should flow into the target at a relatively

high velocity. In Figure 3, lead-glass tracers show that target material in the penetration path

also moves rapidly into the target, implying that it is swept along in the flow of erosion

products. The uniform distribution of tracer material in the penetration path implies mixing and

an opportunity for target material to interact with the side of the jet. This interaction is

confirmed by the abrupt decrease in penetration velocity shortly after closure. Red glass

probably is just a by-product of the initial interaction. However, as it accumulates, it must

become a major influence of the penetration. Judging by the presence of large jet particles

arrested in the red glass, it is highly resistant to penetration. The full role of red glass is not

understood at this time, but possible influences are considered in the final discussion.

2.7 Test for Permanent Densification. One recovery experiment was conducted to verify

that permanent densification occurs during jet penetration into fused quartz. The configuration

of this experiment is shown in Figure 32. The front surface of the fused quartz was

unconfined and surrounded by a trap with a small hole to admit the jet. The shaped charge

for this test produced a relatively massive and slow moving slug that sealed the hole into the

trap. The density of particles recovered from the trap was measured by a procedure similar to

the one reported by Wackerle (1962). Dimethyl formamide was floated over methylene iodide

in a square cuvette. Slight mixing and diffusion of the two liquids produced a column of

varying density which was calibrated by introducing glass particles with different known

44

However. the rate of formation may depend on characteristics of the jet/target interaction.

Figures 20. 22. and 24 suggest that a glass target may interact more strongly with a jet

broken into discrete particles. and it should be noted that the condition of the jet was different

in the two tests with a short jet length. With a 17 mm length. 75% of the penetration was by a

continuous jet. With a 39 mm length. 99% of the penetration was by discrete particles. The

particulated condition of the longer length may have been a factor in the formation of red

glass detected in the target recovered form that experiment.

The photographs in Figures 10 and 16 show fine longitudinal detail which suggests the

termination of radial cracks at the boundary of the penetration path. The appearance was

confirmed when boundary layers were recovered and examined. This observation suggests

that opening and closure are accompanied by brittle failure at the cavity wall. producing glass

particles which mix with material eroded from the jet. The Modified Bernoulli Penetration

Model indicates that erosion products from the jet should flow into the target at a relatively

high velocity. In Figure 3. lead-glass tracers show that target material in the penetration path

also moves rapidly into the target. implying that it is swept along in the flow of erosion

products. The uniform distribution of tracer material in the penetration path implies mixing and

an opportunity for target material to interact with the side of the jet. This interaction is

confirmed by the abrupt decrease in penetration velocity shortly after closure. Red glass

probably is just a by-product of the initial interaction. However. as it accumulates. it must

become a major influence of the penetration. Judging by the presence of large jet particles

arrested in the red glass. it is highly resistant to penetration. The full role of red glass is not

understood at this time. but possible influences are considered in the final discussion.

2.7 Test for Permanent Densification. One recovery experiment was conducted to verify

that permanent densification occurs during jet penetration into fused quartz. The configuration

of this experiment is shown in Figure 32. The front surface of the fused quartz was

unconfined and surrounded by a trap with a small hole to admit the jet. The shaped charge

for this test produced a relatively massive and slow moving slug that sealed the hole into the

trap. The density of particles recovered from the trap was measured by a procedure similar to

the one reported by Wackerle (1962). Dimethyl formamide was floated over methylene iodide

in a square cuvette. Slight mixing and diffusion of the two liquids produced a column of

varying density which was calibrated by introduCing glass particles with different known

44

— TRAP4

FUSED QUARTZ 7— /

n ‘MflflflM4H-J STEEL

Figure 32. Tamet Configuration Used to Recover Permanently Densified Fused Quartz.

densities. Recovered particles were also introduced into the column, and particle locations

were measured by a traveling microscope at a magnification of 60x. This magnification

allowed a careful inspection of each recovered particle to verify that it was not contaminated

with copper. Many uncontaminated particles from the trap were found to be permanently

densified, and the maximum densification was approximately 10YO.

The maximum densification of recovered particles is in close agreement with the results of

Arndt, Hornemann, and Muller (1971) who found that maximum permanent densification of

10.37!/. occurs at a shock stress of 13.5 GPa. However, Cohen and Roy (1965) measured a

maximum permanent densification of 19.1‘?4.when fused quartz was statically compressed to

15.0 GPa at room temperature. Therefore, the maximum densification during shock loading

probably exceeds 10.377., but the residual temperature anneals and reduces the permanent

densification before glass specimens can be recovered for measurements. Highly densified

particles were not found in target material surrounding the penetration path in fused quartz.

However, annealing at 1,173 K causes almost complete recovery in a few minutes (Arndt,

Hornemann, and Muller 1971), and in Figure 28A, remelting around the penetration path in

45

STEEL

Figure 32. Target Configuration Used to Recover Permanently Densified Fused Quartz.

densities. Recovered particles were also introduced into the column, and particle locations

were measured by a traveling microscope at a magnification of 60x. This magnification

allowed a careful inspection of each recovered particle to verify that it was not contaminated

with copper. Many uncontaminated particles from the trap were found to be permanently

densified, and the maximum densification was approximately 10%.

The maximum densification of recovered particles is in close agreement with the results of

Arndt, Hornemann, and Muller (1971) who found that maximum permanent densification of

10.37% occurs at a shock stress of 13.5 GPa. However, Cohen and Roy (1965) measured a

maximum permanent densification of 19.1% when fused quartz was statically compressed to

15.0 GPa at room temperature. Therefore, the maximum densification during shock loading

probably exceeds 10.37%, but the residual temperature anneals and reduces the permanent

densification before glass specimens can be recovered for measurements. Highly densified

particles were not found in target material surrounding the penetration path in fused quartz.

However, annealing at 1,173 K causes almost complete recovery in a few minutes (Arndt,

Hornemann, and Muller 1971), and in Figure 28A, remelting around the penetration path in

45

borosilicate glass implies a probable temperature between 1,100 K and 1,500 K. In a fused

quartz target, where the diameter of the densified column is less than twice the diameter of

the penetration path, heat transfer from the penetration path should produce annealing and

explain the absence of particles with a high permanent densification.

2.8 Examination of Recovered Crystalline Quartz Tamets. The crystalline quartz target

shown in Figure 3B was recovered and examined. A static radiograph of the recovered core

is shown in Figure 33A. The slug was not prevented from entering the target and it

accumulated in the upper part of the penetration path. The forward flow of jet and tracer

material was found in the lower part of the target, with a massive accumulation at the end of

penetration. Cross sections from the lower part of the target are shown in Figures 33B–33D.

Here, the feathery appearance results from jet material which invaded small radial cracks in

the quartz. Cross sections B, C, and D indicate nearly complete closure of the penetration

path. There was no evidence that jet penetration into crystalline quartz was influenced by this

closure, and this suggests that closure resulted mainly from target material displaced at late

times. Factors contributing to this displacement could be the massive accumulation of

material at the end of penetration and the slug which was arrested in the preceding section of

the target. No red glass was detected in the crystalline quartz target shown in Figure 3B.

However, the presence of tantalum carbide may have either influenced the copper/quartz

interaction of obscured the presence of red glass. Other crystalline quartz targets were tested

either without tracers or with tracers of tantalum metal and were found to contain thin deposits

of red glass along the penetration path. This reveals only limited mixing and interaction of the

jet and target materials in crystalline quartz and indicates relatively conventional behavior, with

interaction only along the cavity wall.

3. SUMMARY AND FINAL DISCUSSION

Experimental studies of jet penetration into glass and crystalline quartz reveal differences

that should relate to the ability of these materials to resist penetration. The penetration paths

are different, and the jet and target materials interact differently. Permanent densification also

distinguishes the behavior of glass from that of crystalline quartz and may have a role in the

resistance of glass targets to jet penetration.

46

borosilicate glass implies a probable temperature between 1,100 K and 1,500 K. In a fused

quartz target, where the diameter of the densified column is less than twice the diameter of

the penetration path, heat transfer from the penetration path should produce annealing and

explain the absence of particles with a high permanent densification.

2.8 Examination of Recovered Crystalline Quartz Targets. The crystalline quartz target

shown in Figure 3B was recovered and examined. A static radiograph of the recovered core

is shown in Figure 33A. The slug was not prevented from entering the target and it

accumulated in the upper part of the penetration path. The forward flow of jet and tracer

material was found in the lower part of the target, with a massive accumulation at the end of

penetration. Cross sections from the lower part of the target are shown in Figures 33B-33D.

Here, the feathery appearance results from jet material which invaded small radial cracks in

the quartz. Cross sections B, C, and D indicate nearly complete closure of the penetration

path. There was no evidence that jet penetration into crystalline quartz was influenced by this

closure, and this suggests that closure resulted mainly from target material displaced at late

times. Factors contributing to this displacement could be the massive accumulation of

material at the end of penetration and the slug which was arrested in the preceding section of

the target. No red glass was detected in the crystalline quartz target shown in Figure 3B.

However, the presence of tantalum carbide may have either influenced the copper/quartz

interaction of obscured the presence of red glass. Other crystalline quartz targets were tested

either without tracers or with tracers of tantalum metal and were found to contain thin depOSits

of red glass along the penetration path. This reveals only limited mixing and interaction of the

jet and target materials in crystalline quartz and indicates relatively conventional behavior, with

interaction only along the cavity wall.

3. SUMMARY AND FINAL DISCUSSION

Experimental studies of jet penetration into glass and crystalline quartz reveal differences

that should relate to the ability of these materials to resist penetration. The penetration paths

are different, and the jet and target materials interact differently. Permanent densification also

distinguishes the behavior of glass from that of crystalline quartz and may have a role in the

resistance of glass targets to jet penetration.

46

I--.... -~--

A I-:Omm-l

B

c

HOmm-i

HOmm-l

I-IOmm-l

Figure 33. (A) Static Radiograph of the Crystalline Quartz Target; (8-0) Are Cross Sections of the Target in (A) Showing Cavity Closure.

47

The penetration behavior of crystalline quartz is relatively conventional. The jet is

surrounded by a cavity and there is only limited mixing of jet and target materials, as indicated

by thin deposits of red glass along the penetration path. A recovered target provided

evidence of cavity closure, but there was no substantial evidence that closure occurred early

in the penetration or that it influenced the penetration into crystalline quartz.

Photographic observations indicated less conventional behavior in glass targets. A small

copper jet produces a penetration path which opens to its maximum diameter in a few

microseconds and then closes rapidly after the penetration front passes. The boundary of

permanently densified glass shows only a slight necking associated with elastic recovery of

the surrounding target material. If back-lighted photographs were the only source of

information, then the strong refraction of back light by the permanently densified volume might

be mistaken for opacity associated with fracture. However, with front lighting, the target is

observed to remain transparent in to the boundary of the penetration path where the only

evidence of brittle fracture is detected. Unless bubbles are present, no brittle failure is

detected within the permanently densified volume or in the surrounding target until damage

propagates either from an interface or from the impacted surface. This suggests that initial

closure of the penetration path is caused by recovery from high pressures near the

penetration front and does not result from dilatancy associated with target failure into discrete

particles. Measurements of closure show that the inside diameter of the penetration path

approaches the diameter of the jet, producing an interaction which is detected by an abrupt

decrease in the penetration velocity (increase in resistance to penetration). Flash radiographs

show that the jet is disrupted in a glass target, and it is concluded that path closure is the

primary influence.

The boundary of the penetration path in glass exhibits features of brittle failure, and brittle

behavior both at peak interface pressures and after pressure release is consistent with data

presented in Figure 31. Brittle failure of target material at the boundary of the penetration

path is also consistent with the presence of glass particles in the penetration path. Initially,

the glass particles must be permanently densified as a result of high pressures experienced at

the penetration front. Glass particles accumulate in the penetration path where they interact

with the jet and its erosion products. This interaction causes melting of the glass particles and

both melting and vaporization of copper jet material. Melting produces a volume recovery of

48

The penetration behavior of crystalline quartz is relatively conventional. The jet is

surrounded by a cavity and there is only limited mixing of jet and target materials, as indicated

by thin deposits of red glass along the penetration path. A recovered target provided

evidence of cavity closure, but there was no substantial evidence that closure occurred early

in the penetration or that it influenced the penetration into crystalline quartz.

Photographic observations indicated less conventional behavior in glass targets. A small

copper jet produces a penetration path which opens to its maximum diameter in a few

microseconds and then closes rapidly after the penetration front passes. The boundary of

permanently densified glass shows only a slight necking associated with elastic recovery of

the surrounding target material. If back-lighted photographs were the only source of

information, then the strong refraction of back light by the permanently densified volume might

be mistaken for opacity associated with fracture. However, with front lighting, the target is

observed to remain transparent in to the boundary of the penetration path where the only

evidence of brittle fracture is detected. Unless bubbles are present, no brittle failure is

detected within the permanently densified volume or in the surrounding target until damage

propagates either from an interface or from the impacted surface. This suggests that initial

closure of the penetration path is caused by recovery from high pressures near the

penetration front and does not result from dilatancy associated with target failure into discrete

particles. Measurements of closure show that the inside diameter of the penetration path

approaches the diameter of the jet, producing an interaction which is detected by an abrupt

decrease in the penetration velocity (increase in resistance to penetration). Flash radiographs

show that the jet is disrupted in a glass target, and it is concluded that path closure is the

primary influence.

The boundary of the penetration path in glass exhibits features of brittle failure, and brittle

behavior both at peak interface pressures and after pressure release is consistent with data

presented in Figure 31. Brittle failure of target material at the boundary of the penetration

path is also consistent with the presence of glass particles in the penetration path. Initially,

the glass particles must be permanently densified as a result of high pressures experienced at

the penetration front. Glass particles accumulate in the penetration path where they interact

with the jet and its erosion products. This interaction causes melting of the glass particles and

both melting and vaporization of copper jet material. Melting produces a volume recovery of

48

the glass and, together with porosity, enables glass to fill the penetration path. The red color

gradually develops as copper becomes suspended and partially reacts with the glass.

Porosity in red glass is tentatively attributed to pockets of vaporized jet material which

eventually condenses to coat the surface of pores. Steel jets have been found to produce

relatively little porosity in glass that accumulates in the penetration path, and this is consistent

with a vaporization temperature higher than that of copper. The greater effectiveness of steel

jets against glass targets (Heine-Geldern 1954; Allison 1960) suggests that vaporization and

the resulting porosity have an influence on the jetitarget interaction.

Material flow in the penetration path is another potential influence on the jet. The

penetration model indicates that erosion products, in most cases, flow into glass targets at a

high rate. Tracer experiments indicate that local target material accompanies the flow of

erosion products. Material flow within an irregular penetration path, as shown in Figure 14,

may contribute to disruption of the jet. Layering dissimilar target materials should also

produce irregular penetration paths which may be disruptive, especially during oblique

penetration.

Although dilatancy associated with brittle failure is not the primary cause of path closure in

targets of soda-lime gas, it may make a secondary contribution. When failure occurred at

bubbles in a glass target, the early increase in target resistance may have resulted from a

contribution of dilatancy to path closure. Also, if dilatancy is able to bulge the front steel

confinement of glass targets (the “rebound effect” [Heine-Geldern 1954; Allison 1960]) it may

also contribute to jet disruption by opposing reopening of the penetration path which is shown

in Figures 14 and 17.

49

the glass and, together with porosity, enables glass to fill the penetration path. The red color

gradually develops as copper becomes suspended and partially reacts with the glass.

Porosity in red glass is tentatively attributed to pockets of vaporized jet material which

eventually condenses to coat the surface of pores. Steel jets have been found to produce

relatively little porosity in glass that accumulates in the penetration path, and this is consistent

with a vaporization temperature higher than that of copper. The greater effectiveness of steel

jets against glass targets (Heine-Geldern 1954; Allison 1960) suggests that vaporization and

the resulting porosity have an influence on the jeVtarget interaction.

Material flow in the penetration path is another potential influence on the jet. The

penetration model indicates that erosion products, in most cases, flow into glass targets at a

high rate. Tracer experiments indicate that local target material accompanies the flow of

erosion products. Material flow within an irregular penetration path, as shown in Figure 14,

may contribute to disruption of the jet. Layering dissimilar target materials should also

produce irregular penetration paths which may be disruptive, especially during oblique

penetration.

Although dilatancy associated with brittle failure is not the primary cause of path closure in

targets of soda-lime gas, it may make a secondary contribution. When failure occurred at

bubbles in a glass target, the early increase in target resistance may have resulted from a

contribution of dilatancy to path closure. Also, if dilatancy is able to bulge the front steel

confinement of glass targets (the "rebound effect" [Heine-Geldern 1954; Allison 1960]) it may

also contribute to jet disruption by opposing reopening of the penetration path which is shown

in Figures 14 and 17.

49

lNTEtNwONALLYLWT BUNK.

50

INTENTIONALLY LEFT BLANK.

50

4. REFERENCES

Allison, F. E. “Defeat of Shaped Charge Weapons.” Final report, Contract No.DA-36-061 -ORD-507 Carnegie Institute of Technology, Pittsburgh, PA, April 1960.

Anan’in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, A. 1.Rogacheva, and V. F, Tatsii.“Action of Shock Waves in Silicon Dioxide Il. Quartz Glass.” Fizika Goreniva i Vzryva,vol. 10, pp. 578–583, July–August 1974a.

Anan’in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, and V. F. Tatsii. “The Effect ofShock Waves on Silicon Dioxide 1. Quartz.” Fizika Goreniya i Vzryva, vol. 10,pp. 426436, May-June 1974b.

Arndt, J., U. Hornemann, and W. F. Muller. “Shock-Wave Densification of Silica Glass.”Phvsics and Chemistrv of Glasses, vol. 12, pp. 1–7, February 1971.

Bridgman, P. W., and 1.Simon. “Effects of Very High Pressure on Glass.” Journal of Applied

=$ vol. 24, pp. 405-413, April 1953.

Cagnoux, J. “Shock-Wave Compression of a Borosilicate Glass Up to 170 kbar.” Paperpresented at the APS Conference, Stanford Research institute, Menlo Park, CA, June 1981.

Cohen, H. M., and R. Roy. “Densification of Glass at Very High Pressures.” Physics andChemistry of Glasses, vol. 6, pp. 149-161, October 1965.

Franz, R. E., and W. Lawrence. “Design of a System for Cutting Shaped Charge Jets forPenetration Experiments.” BRL-MR-3608, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, June 1987.

Gibbons, R. V., and T. J. Ahrens. “Shock Metamorphism of Silicate Glasses.” Journal ofGeophysical Research, vol. 76, pp. 5489–5497, August 1971.

Hauver, G. E., and K. A. Benson. “Asymmetry of Detonation Waves Emerging From M36 andM36-M18 Initiated Tetryl Pellets.” BRL-MR-893, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, May 1955.

Heine-Geldern, R. V. “Critical Review of Shaped Charge Information: Chapter IX. Defeat ofShaped Charge Weapons.” BRL Report 905, U.S. Army Ballistic Research Laboratory,Aberdeen Proving Ground, MD, May 1954.

Kanel, G. l., A. M. Molodets, and A. N. Dremin. “Investigation of Singularities of Glass StrainUnder Intense Compression Waves.” Fizika Goreniya i Vzryva, vol. 13, pp. 906-912,November–December 1976.

Meade, E., and R. Jeanloz. “Effect of Coordination Change on the Strength of AmorphousSilica.” Science, vol. 241, pp. 1072–1074, 26 August 1988.

51

4. REFERENCES

Allison, F. E. "Defeat of Shaped Charge Weapons." Final report, Contract No. DA-36-061-0RD-507 Carnegie Institute of Technology, Pittsburgh, PA, April 1960.

Anan'in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, A. I. Rogacheva, and V. F. Tatsii. "Action of Shock Waves in Silicon Dioxide II. Quartz Glass." Fizika Goreniya i Vzryva, vol. 10, pp. 578-583, July-August 1974a.

Anan'in, A. V., O. N. Breusov, A. N. Dremin, S. V. Pershin, and V. F. Tatsii. "The Effect of Shock Waves on Silicon Dioxide I. Quartz." Fizika Goreniya i Vzryva, vol. 10, pp. 426-436, May-June 1974b.

Arndt, J., U. Hornemann, and W. F. Muller. "Shock-Wave Densification of Silica Glass." Physics and Chemistry of Glasses, vol. 12, pp. 1-7, February 1971.

Bridgman, P. W., and I. Simon. "Effects of Very High Pressure on Glass." Journal of Applied Physics, vol. 24, pp. 405-413, April 1953.

Cagnoux, J. "Shock-Wave Compression of a Borosilicate Glass Up to 170 kbar." Paper presented at the APS Conference, Stanford Research Institute, Menlo Park, CA, June 1981.

Cohen, H. M., and R. Roy. "Densification of Glass at Very High Pressures." Physics and Chemistry of Glasses, vol. 6, pp. 149-161, October 1965.

Franz, R. E., and W. Lawrence. "Design of a System for Cutting Shaped Charge Jets for Penetration Experiments." BRL-MR-3608, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, June 1987.

Gibbons, R. V., and T. J. Ahrens. "Shock Metamorphism of Silicate Glasses." Journal of Geophysical Research, vol. 76, pp. 5489-5497, August 1971.

Hauver, G. E., and K. A. Benson. "Asymmetry of Detonation Waves Emerging From M36 and M36-M18 Initiated Tetryl Pellets." BRL-MR-893, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, May 1955.

Heine-Geldern, R. V. "Critical Review of Shaped Charge Information: Chapter IX. Defeat of Shaped Charge Weapons." BRL Report 905, U.S. Army Ballistic Research L.aboratory, Aberdeen Proving Ground, MD, May 1954.

Kanel, G. I., A. M. Molodets, and A. N. Dremin. "Investigation of Singularities of Glass Strain Under Intense Compression Waves." Fizika Goreniya i Vzryva, vol. 13, pp. ~106-912, November-December 1976.

Meade, E., and R. Jeanloz. "Effect of Coordination Change on the Strength of Amorphous Silica." Science, vol. 241, pp. 1072-1074, 26 August 1988.

51

Meyer, H.W. "investigation of the H~ersonic Flotield Surrounding aSh~ed Charge Jet."BRL-TR-2883, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD,December 1987.

Proctor, B. A., 1.Whitney, and J. W. Johnson. “The Strength of Fused Silica.” Proceedings ofthe Royal Society of London Ser. A, vol. 297, pp. 534-557, 21 March 1967.

Pugh, E. M., R. V. Heine-Geldern, S. Foner, and E. Mutschler. “Kerr Cell Photography ofHigh Speed Phenomena.” Journal of Adied Physics, vol. 22, pp. 487-493, April 1951.

Sugiura, H., K. Kondo, and A. Sawaoka. “Dynamic Response of Fused Quartz in thePermanent Densification Region.” Journal of Applied Physics, vol. 52, pp. 3375-3382,May 1981.

Tate, A. “A Theory for the Deceleration of Long Rods After Impact.” Journal of theMechanics and Physics of Solids, vol. 15, pp. 387-399, 1967.

Tate, A. “Further Results in the Theory of Long Rod Penetration.” Journal of the Mechanicsand Physics of Solids, vol. 17, pp. 141–150, 1969.

Viard, J. “Hugoniot Curve of Vitreous Silica and Crystallization Under Shock.” Com~tesRendus. Academie des Sciences (Paris), vol. 249, pp. 820-822, 1959.

Wackerle, J. “Shock-Wave Compression of Quartz.” Journal of Ar@ied Physics, vol. 33,pp. 922-937, March 1962.

Weyl, W. A. Couloured Glasses. Published by the Society of Glass Technology - England,Distributed by State Mutual Book and Periodical Services, NY, 1951.

Zernow, L., D. Garfinkle, D. Buhman, and J. Burchfield. “Final Report on the Evaluation ofNew Armor Concepts.” Report no. 220, Shock Hydrodynamics Inc., Sherman Oaks, CA,April 1975.

Zernow, L., and G. Hauver. “Study of Jet Penetration Into Glass Targets.” Sh~ed CharcaeJournal, April 1955.

52

Meyer, H. W. "Investigation of the Hypersonic Flowfield Surrounding a Shaped Charge Jet." BRL-TR-2883, U.S. Army Ballistic Research Laboratory, Aberdeen Proving Ground, MD, December 1987.

Proctor, B. A., I. Whitney, and J. W. Johnson. "The Strength of Fused Silica." Proceedings of the Royal Society of London Ser. A, vol. 297, pp. 534-557, 21 March 1967.

Pugh, E. M., R. V. Heine-Geldern, S. Foner, and E. Mutschler. "Kerr Cell Photography of High Speed Phenomena." Journal of Applied Physics, vol. 22, pp. 487-493, April 1951.

Sugiura, H., K. Kondo, and A. Sawaoka. "Dynamic Response of Fused Quartz in the Permanent Densification Region." Journal of Applied Physics, vol. 52, pp. 3375-3382, May 1981.

Tate, A. "A Theory for the Deceleration of Long Rods After Impact." Journal of the Mechanics and Physics of Solids, vol. 15, pp. 387-399, 1967.

Tate, A. "Further Results in the Theory of Long Rod Penetration." Journal of the Mechanics and Physics of Solids, vol. 17, pp. 141-150, 1969.

Viard, J. "Hugoniot Curve of Vitreous Silica and Crystallization Under Shock." Comptes Rendus. Academie des Sciences (Paris), vol. 249, pp. 820-822, 1959.

Wackerle, J. "Shock-Wave Compression of Quartz." Journal of Applied Physics, vol. 33, pp. 922-937, March 1962.

Weyl, W. A. Couloured Glasses. Published by the Society of Glass Technology - England, Distributed by State Mutual Book and Periodical Services, NY, 1951.

Zernow, L., D. Garfinkle, D. Buhman, and J. Burchfield. "Final Report on the Evaluation of New Armor Concepts." Report no. 220, Shock Hydrodynamics Inc., Sherman Oaks, CA, April 1975.

Zernow, L., and G. Hauver. "Study of Jet Penetration Into Glass Targets." Shaped Charge Journal, April 1955.

52

No. of

!Z?@2S

2

1

1

2

2

1

Organization

AdministratorDefenseTechnical Info CenterAlTN: DTIC-DDACameronStationAlexandria,VA 22304-6145

CommanderU.S. Army Materiel CommandAlTN: AMCDRA-ST5001 Eisenhower AvenueAlexandria, VA 22333-0001

CommanderU.S. Army Laboratory CommandAlTN: AMSLC-DL2800 Powder Mill RoadAdelphi, MD 20783-1145

CommanderU.S. Army Armament Research,

EhWdODmt?nt, and Enaineerina Center

No. of

GQll!?S

1

1

1

1

A_tTN: $MCAR-IMI-I - - (class. Only)l

Picatinny Arsenal, NJ 07806-5000

CommanderU.S. Army Armament Research,

Development, and Engineering Center (uncla= WIIY)l

AlTN: SMCAR-TDCPicatinny Arsenal, NJ 07806-5000

DirectorBenet Weapons Laboratory 1U.S. Army Armament Research,

Development, and Engineering CenterAlTN: SMCAR-CCB-TLWatervliet, NY 12189-4050

Unclaaa. only)l Commander 2U.S. Army Armament, Munitions

and Chemical CommandAlTN: AMSMC-IMF-LRock Island, IL 61299-5000 1

1 DirectorU.S. Army Aviation Research 3

and Technology ActivityAlTN: SAVRT-R (Library)MIS 219-3Ames Research CenterMoffett Field, CA 94035-1000 1

10

Organization

CommanderU.S. Army Missile CommandAlTN: AMSMI-RD-CS-R (DOC)Redstone Arsenal, AL 35898-5010

CommanderU.S. Army Tank-Automotive CommandAlTN: ASQNC-TAC-DIT (Technical

lnformatllon Center)Warren, Ml 48397-5000

DirectorU.S. Army TRADOC Analysis CommandAlTN: ATRC-WSRWhite Sands Missile Range, NM 88002-5502

CommandantU.S. Army Field Artillery SchoolAlTN: ATSF-CSIFt. Sill, OK 73503-5000

CommandantU.S. Army Infantry SchoolAlTN: ATSH-CD (Security Mgr.)Fort Benning, GA 31905-5660

CommandantU.S. Army Infantry SchoolAlTN: ATSH-CD-CSO-ORFort Benning, GA 31905-5660

Air Force Armament LaboratoryAlTN: WL/MNOlEglin AFB, FL 32542-5000

Aberdeen Provina Ground

Dir, USAMSAAAlTN: AMXSY-D

AMXSY-MP, H. Cohen

Cdr, USATECOMATTN: AMSTE-TC

Cdr, CRDEC, AMCCOMAlTN: SMCCR-RSP-A

SMCCR-MUSMCCR-MSI

Dir, VLAMOATTN: AMSLC-VL-D

Dir, BRLAlTN: SLCBR-DD-T

53

No. of No. of Copies Organization Copies Organization

2 Administrator 1 Commander Defense Technical Info Center U.S. Army Missile Command ATTN: DTIC-DDA ATTN: AMSMI-RD-CS-R (DOC) Cameron Station Redstone Arsenal, AL 35898-5010 Alexandria, VA 22304-6145

1 Commander Commander U.S. Army Tank-Automotive Command U.S. Army Materiel Command ATTN: ASQNC-TAC-DIT (Technical ATTN: AMCDRA-ST Informatilon Center) 5001 Eisenhower Avenue Warren, M I 48397-5000 Alexandria, VA 22333-0001

1 Director 1 Commander U.S. Army TRADOC Analysis Command

U.S. Army Laboratory Command ATTN: ATRC-WSR ATTN: AMSLC-DL White Sands Missile Range, NM 88002-5502 2800 Powder Mill Road Adelphi, MD 20783-1145 Commandant

U.S. Army Field Artillery School 2 Commander ATTN: ATSF-CSI

U.S. Army Armament Research, Ft. Sill, OK 73503-5000 Development, and Engineering Center

ATTN: SMCAR-IMI-I (Class. on1Y)1 Commandant Picatinny Arsenal, NJ 07806-5000 U.S. Army Infantry School

ATTN: ATSH-CD (Security Mgr.) 2 Commander Fort Benning, GA 31905-5660

U.S. Army Armament Research, Development, and Engineering Center (Unclass. on1Y)1 Commandant

ATTN: SMCAR-TDC U.S. Army Infantry School Picatinny Arsenal, NJ 07806-5000 ATTN: ATSH-CD-CSO-OR

Fort Benning, GA 31905-5660 1 Director

Benet Weapons Laboratory 1 Air Force Armament Laboratory U.S. Army Armament Research, ATTN: WUMNOI

Development, and Engineering Center Eglin AFB, FL 32542-5000 ATTN: SMCAR-CCB-TL Watervliet, NY 12189-4050 Aberdeen Proving Ground

Unclass. onlY)1 Commander 2 Dir, USAMSAA U.S. Army Armament, Munitions ATTN: AMXSY-D

and Chemical Command AMXSY-MP, H. Cohen ATTN: AMSMC-IMF-L Rock Island, IL 61299-5000 1 Cdr, USATECOM

ATTN: AMSTE-TC 1 Director

U.S. Army Aviation Research 3 Cdr, CRDEC, AMCCOM and Technology Activity ATTN: SMCCR-RSP-A

ATTN: SAVRT-R (Library) SMCCR-MU MIS 219-3 SMCCR-MSI Ames Research Center Moffett Field, CA 94035-1000 1 Dir, VLAMO

ATTN: AMSLC-VL-D

10 Dir, BRL ATTN: SLCBR-DD-T

53

No. of

@@ Organization

No. of

GQ12@Organization

1 DirectorCentral Intelligence AgencyAlTN: W. Waltman, OSWR/OSD/GPWBP.O. BOX 1925Main StationWashington, DC 20505

1 CommanderU.S. Army Intelligence AgencyForeign Science and Technology

CenterAll_N: M. Scott Mingledorlf220 Seventh Street, NECharlottesville, VA 22901-5396

1 U.S. Army Research OfficeATTN: Dr. K. IyerP.O. Box 12211Research Triangle Park, NC 27709

5 DirectorU.S. Army Materials Technology

LaboratoryAlTN: SLCMT-MRD,

Dr. G. BishopDr. S-C ChouDr. D. ViechnickiDr. D. DandekarMr. P. Woolsey

Arsenal StreetWatertown, MA 02172-0001

1 DirectorDefense Advanced Research

Projects AgencyATTN: LTC J. H. Beno1400 Wilson Blvd.Arlington, VA 22209-2308

1 Air Force Armament LaboratoryAlTN: AD/CZL (W. Dyess)Eglin Air Force Base, FL 32542-5000

3 Los Alarrms National LaboratoryATTN: Dr. G. E. Cort, MS K574

Dr. R. Karpp, MS P940Dr. L. M. Hull, MS J960

P.O. E!OX 1663

Los Alamos, NM 87545

3

2

1

1

1

1

1

1

1

Lawrence Livermore NationalLaboratory

AlTN: Dr. L. Glenn, MS L-200Mr. J. Reaugh, MS L-290Mr. B. Moran, MS L-200

P.O. Box 808Livermore, CA 94550

Sandia National LaboratoriesAlTN: Dr. M. J. Forrestal

Dr. Dennis GradyP.O. BOX 5800Albuquerque, NM 87185

Southwest Research InstituteAlTN: Dr. C. E. Anderson, Div. 6P.O. Drawer 28510San Antonio, TX 78284

California Research & TechnologyATTN: Dr. D. Orphal5117 Johnson DrivePleasanton, CA 94566

General Research CorporationAlTN: Dr. A. Charters5383 Hollister AvenueSanta Barbara, CA 93160-6770

Battelle, Edgewood OperationsAl’TN: R. Jameson, Suite 2002113 Emmorton Park RoadEdgewood, MD 21040

E. 1.DuPont DeNemours & CompanyAlTN: B. Scott

Chestnut Run - CR 702Wilmington, DE 19898

Univ. of Dayton Research Inst.AITN Dr. S. J. BlessDayton, OH 45469

Zernow Technical Services, inc.ATTN: Dr. Louis Zernow425 W. Bonita Ave., Suite 208San Dimas, CA 92121

54

No. of Copies Organization

1

5

3

Director Central Intelligence Agency AnN: W. Waltman, OSWR/OSD/GPWB P.O. Box 1925 Main Station Washington, DC 20505

Commander U.S. Army Intelligence Agency Foreign Science and Technology

Center AnN: M. Scott Mingledorff 220 Seventh Street, NE Charlottesville, VA 22901-5396

U.S. Army Research Office AnN: Dr. K. Iyer P.O. Box 12211 Research Triangle Park, NC 27709

Director U.S. Army Materials Technology

Laboratory AnN: SLCMT-MRD,

Dr. G. Bishop Dr. S-C Chou Dr. D. Viechnicki Dr. D. Dandekar Mr. P. Woolsey

Arsenal Street Watertown, MA 02172-0001

Director Defense Advanced Research

Projects Agency AnN: LTC J. H. Beno 1400 Wilson Blvd. Arlington, VA 22209-2308

Air Force Armament Laboratory AnN: AD/CZL (W. Dyess) Eglin Air Force Base, FL 32542-5000

Los Alamos National Laboratory AnN: Dr. G. E. Cort, MS K574

Dr. R. Karpp, MS P940 Dr. L. M. Hull, MS J960

P.O. Box 1663 Los Alamos, NM 87545

54

No. of Copies Organization

3

2

1

1

1

1

Lawrence Livermore National Laboratory

AnN: Dr. L. Glenn, MS L-200 Mr. J. Reaugh, MS L-290 Mr. B. Moran, MS L-200

P.O. Box 808 Livermore, CA 94550

Sandia National Laboratories AnN: Dr. M. J. Forrestal

Dr. Dennis Grady P.O. Box 5800 Albuquerque, NM 87185

Southwest Research Institute AnN: Dr. C. E. Anderson, Div. 6 P.O. Drawer 28510 San Antonio, TX 78284

California Research & Technology AnN: Dr. D. Orphal 5117 Johnson Drive Pleasanton, CA 94566

General Research Corporation AnN: Dr. A. Charters 5383 Hollister Avenue Santa Barbara, CA 93160-6770

Battelle, Edgewood Operations AnN: R. Jameson, Suite 200 2113 Emmorton Park Road Edgewood, MD 21040

E. I. DuPont DeNemours & Company AnN: B. Scott Chestnut Run - CR 702 Wilmington, DE 19898

Univ. of Dayton Research Inst. AnN Dr. S. J. Bless Dayton, OH 45469

Zernow Technical Services, Inc. AnN: Dr. Louis Zernow 425 W. Bonita Ave., Suite 208 San Dimas, CA 92121

.—

No. of

- Organization

1 Dr. R. J. Eichelberger409 Catherine StreetBel Air, MD 21014

2 Teledyne Brown EngineeringArmor Technology, Strategic

Systems DivisionATTN: Mr. D. L. Puckett

Dr. D. N. HansenCummings Research Park300 Sparkman Drive, NWHuntsville, AL 35807-7007

55

No. of Copies Organization

Dr. R. J. Eichelberger 409 Catherine Street Bel Air, MD 21014

2 Teledyne Brown Engineering Armor Technology, Strategic

Systems Division AnN: Mr. D. L. Puckett

Dr. D. N. Hansen Cummings Research Park 300 Sparkman Drive, NW Huntsville, AL 35807-7007

55

No. ofCopies Organization

1 Mr. D. E. FinchAA4 DivisionRARDE(FH),SevenoaksKent TN14 76P, UK

1 Mr. Gerard SolveCenter D’Etudesde Gramat46500 Gramat, France

1 Mr. Patrick BarnierEtablissment Technique de BourgesCarrefour de Zero - Nerd - Route

de GuerryBP712 18015 Bourges Cedex France

1 Dr. U. HornemannFraunhofer-lnstitut,EMIInstitutsteilWeil am RheinPostfach 1270D-7858 Weil am Rhein, Germany

1 Dr. Ives RemiliieuxChef du DepartmentCompartment des MateriauxEtabfissementTechnque Central

de L’armement16 bis Avenue Prieurde la Cote

d’Or94114 Arcueil Cedex France

1 Dr. FlorenceTardivelCompadmentdes MateriauxEtablissementTechniqueCentral

de L’arrnement16 bis Avenue Prieurde la Cote

d’Or94114 Arcueil Cedex France

56

No. of Copies Organization

1 Mr. O. E. Finch AA4 Division RAROE(FH}, Sevenoaks Kent TN14 7BP, UK

1 Mr. Gerard Solve Center O'Etudes de Gramat 46500 Grarnat. France

1 Mr. Patrick Barnier Etablissment Technique de Bourges Carrefour de Zero - Nord - Route

de Guerry BP712 18015 Bourges Cede x France

1 Dr. U. Hornemann Fraunhofer-Institut. EMI Institutsteil Weil am Rhein Postfach 1270 0-7858 Weil am Rhein, Germany

1 Dr. Ives Remillieux Chef du Oepartement Compartement des Materiaux Etablissement Technique Central

de L'armement 16 bis Avenue Prieur de la Cote

d'Or 94114 Arcueil Cedex France

1 Dr. Florence Tardivel Compartment des Materiaux Etablissement Technique Central

de L'armement 16 bis Avenue Prieur de la Cote

d'Or 94114 Arcueil Cedex France

56

USER EVALUATION SHEET/CHANGE OF ADDRESS

This laboratory undertakes a continuing effort to improve the quality of the reports itpublishes. Your comments/answers below will aid us in our efforts.

1. Does this report satisfy a need? (Comment on purpose, related project, or other area ofinterest for which the report will be used.)

2. How, specifically, is the report being used? (Information source, design data, procedure,source of ideas, etc.)

3. Has the information in this report led to any quantitative savings as far as man-hours ordollars saved, operating costs avoided, or efficiencies achieved, etc? If so, pIeaseelaborate.

4. General Comments. What do you think should be changed to improve future reports?(Indicate changes to organization, technical content, format, etc.)

BRL Report Number BRL-TR-3273 Division Symbol

Check here if desire to be removed from distribution list. _

Check here for address change. _

Current address: OrganizationAddress

DEPARTMENT OF THE ARMYDirectorU.S. Army Ballistic Research LaboratoryATTN:SLCBR-DD-TAberdeen Proving Ground, MD 21005-5066

OFllCIALBUSINESS I BUSINESSREPLY MAILFIRST CUSS ffRMIT h 0001, M%, MO

Postage will be paid by addressee

DirectorU.S. Army Ballistic Research LaboratoryATTN: SLCBR-DD-T

II NOPOSTAGENECESSAllVIFMAILED

INTl+EUNITEE)STAIES

Aberdeen Proving Ground, MD 21005-5066

USER EVALUATION SHEET/CHANGE OF ADDRESS

This laboratory undertakes a continuing effort to improve the quality of the reports it publishes. Your comments/answers below will aid us in our efforts.

1. Does this report satisfy a need? (Comment on purpose, related project, or other area of interest for which the report will be used.)

2. How, specifically, is the report being used? (Information source, design data, procedure, source of ideas, etc.)

3. Has the information in this report led to any quantitative savings as far as man-hours or dollars saved, operating costs avoided, or efficiencies achieved, etc? If so, please elaborate.

4. General Comments. What do you think should be changed to improve future reports? (Indicate changes to organization, technical content, format. etc.)

BRL Report Number _____ B_RL_-_TR_-_3_2_7_3_ Division Symbol __________ _

Check here if desire to be removed from distribution list.

Check here for address change. __

Current address: Organization Address

DEPARTMENT OF THE ARMY I Director U.S. Army Ballistic Research Laboratory AnN: SLCBR-OO-T Aberdeen Proving Ground, MD 21005-5066

OFRCIAL BUSINESS BUSINESS REPLY MAIL ARST CLASS PERMIT rtJ 000', APG, MO

Postage will be paid by addressee

Director U.S. Army Ballistic Research Laboratory ATTN: SLCBR-DD-T Aberdeen Proving Ground, MD 21005-5066

NO POSTAGE NECESSARY

IF MAILED IN THE

UNITED STATES