Pure Tungsten HCal : ‘staircase’ design

Pure Tungsten HCal: ‘staircase’ design

Structural analyses and possible optimizations

Niall O Cuilleanain (Supervisor: H. Gerwig)

The design

27 August, 2009

Basic Facts

Total weight: c. 640 tons + weight of ECal

Length: 3500mm

Interior arc width: 494mm

Exterior arc width: 972mm

Internal radius: 1400mm

3 MODULES = 1 SECTOR

External Middle Internal

TUNGSTEN PLATES INSERTION

next plate

screw

spacer

The first 6 plates are

bolted together between

spacers and the followings two by two

A specific tool for insertion is needed due to the fragility of

the plates

side viewFirst module ready to

be assembled with the next


What has been looked at?

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• Initial analysis of single sector

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• Added rigidity of tungsten plates in single sector

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• Crane supports of single sector

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• Added rigidity of pure tungsten plates in single sector


• Initial analysis of individual pure tungsten plates

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• Initial analysis of individual tungsten plates

• Initial analysis of entire module

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What has been looked at?• Initial analysis of single sector





• Effect of the added load of the ECal

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What has been looked at?• Initial analysis of single sector





• Effect of the added load of the ECal

• Optimization

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Single sectorDimensions of note:

Exterior shell/ plate: 75mm

Interior shell/ plate: 46.5mm

“Fins”External: 30mmMiddle: 25mmInternal: 18mm

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Single sector - Deformation

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Single sector – V. Mises

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Analysis of added rigidity of tungsten plates to a single sector

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Model 1 (steel structure only): The Tungsten plates are represented by a virtual density. In this case, the tungsten is ‘dead weight’.

Model 2 (both steel structure & the connected Tungsten plates):The plates are ‘bonded’ to the structureas opposed to bolted.The added rigidity of the plates will, in reality, not be so great.

Both models are supported at the section’s external face, and are loaded under Standard Gravity.


Analysis of added rigidity of tungsten plates to a single sector

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Model 1 Model 2

168

63

V. Mises [MPa]V. Mises [MPa]

Model 1 Model 2

2.97

1.63

Deformation [mm]Deformation [mm]


Crane supports

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Crane supports

• 4 different configurations were chosen and compared

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Crane support “1”

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Crane support “1” -Deformation

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Crane support “1”- V. Mises

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Crane support “2” -Deformation

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Crane support “2” – V. Mises

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Crane support “3” - Deformation

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Crane support “3” – V. Mises

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“Ideal” crane support

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“Ideal” crane support - Deformation

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“Ideal” crane support – V. Mises

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Crane support

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0

20

40

60

80

100

120

140

Series1; 118 122.47

33.94

4.06

V.Mises [MPa] under different crane support conditions

Crane support condition

Max

. V.M

ises [

MPa

]

00.10.20.30.40.50.60.70.80.9

1

Series1; 0.649

0.926

0.202

0.01

Deformation [mm] under different crane support conditions

Crane support condition

Max

. Def

orm

ation

[mm

]



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Crane support

• It is clear from the analyses where from one should support the sector while it is being hoisted by a crane during assembly.

• (This analysis will be useful again as comparison with the optimization of the number of contact regions between sectors).

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Simple Tungsten plate analysis2 different plates were analyzed:

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Simple Tungsten plate analysis2 different plates were analyzed:

-The top plate of a sector,

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Simple Tungsten plate analysis

2 different plates were analyzed:

-The top plate of a sector,

-and the bottom plate of a sector

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Niall O Cuilleanain (Supervisor: H. Gerwig)27 August, 2009

12mm [plaque en haut] 12mm [plaque en bas]

83.865

21.113

V.Mises [MPa]V.Mises [MPa]

12mm [plaque en haut] 12mm [plaque en bas]

0.56587

0.22112



Simple Tungsten plate analysis

The bottom plate was also analyzed at 3 different thicknesses:

-10mm-12mm-13,5mm

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10 12 13.5

104.69

83.865

72.082

Effect of plate thickness on equivalent stresses

Plate thickness [mm]

Max

. V. M

ises [

MPa

]

10 12 13.5

0.74923

0.56587

0.45313

Effect of plate thickness on defor-mation

Plate thickness [mm]

Max

. Def

orm

ation

[mm

]

12mm appears to be a reasonable value


Entire Lattice

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Max. V. Mises:53. 178 MPa.

Max. Deformation:

0.758 mm.

*Virtual density applied= 62.55


Additional loading of the ECal

•The loading of the ECal is approximated by a remote force applied at the centre of the structure

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•The loading of the ECal is approximated by a remote force applied at the centre of the structure

•And it acts on the inner surface of the HCal.

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27 August, 2009

Lattice under its own static weight Lattice under its own static weight +120ton ECal

113.26

135.66

Max. stresses of lattice w/ & w/o loading of 120 ton ECal

V.Mises [MPa]

Lattice under its own static weight Lattice under its own static weight +120ton ECal

1.227

1.563

Deformation [mm] of lattice w/ & w/o loading of 120 ton ECal

Deformation [mm]


What next?

• Following the initial analyses, the next step was to see where the structure could be optimized, in doing so optimizing the tungsten’s surface area within the structure.

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What next?

Possible optimization points of the structure:

•Contact regions between sectors

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What next?



• “Fin” thickness

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What next?




•Exterior shell thickness

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What next?




•Exterior shell thickness

•Interior shell thickness

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Effect of level of contact between sectors

• Three configurations were analyzed:

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-All 4 steel plates are connected

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-Only 3 steel plates are connected.

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-Only 3 steel plates are connected.

-Only the 2 end plates are connected.

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All 4 contact regions are in contact – an entirely homogeneous structureThis is similar to the “ideal” crane support, as seen earlier.

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1 steel plate is not in contactThis is similar to crane support ”3”, as seen earlier.

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2 steel plates are not in contactThis is similar to crane support “1”, as seen earlier.

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All Contacts 1 Contact Missing 2 Contacts Missing

53.17860.347

131.18

Effect of level of contact on V.Mises [MPa]

V.Mises [MPa]

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All Contacts 1 Contact Missing 2 Contacts Missing

0.758

1.111

1.543

Effect of level of contact on max-imum deformation [mm]

Deformation [mm]


Effect of “fin” thickness

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External

Middle

Internal


Effect of “fin” thickness [mm]

• 4 different configurations of fin thicknesses were studied:

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Dimensions External Middle Internal

Conservative 35 30 25

Original 30 25 18

Optimal 26 21 14

Extreme 15 12,5 9


ext35,mid30,int25 ext30,mid25,int18 (original) ext26,mid21,int14 ext15,mid12.5,int090

10

20

30

40

50

60

70

80

90

100

V.Mises[MPa] at different configurations of fin thicknesses [mm]


ext35,mid30,int25 ext30,mid25,int18 (original) ext26,mid21,int14 ext15,mid12.5,int090

0.2

0.4

0.6

0.8

1

1.2

Deformation [mm] at different configurations of fin thicknesses [mm]


Effect of exterior shell thickness

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253545556575

225.89

164.04

117.03115.38113.26111.09

V.Mises [MPA]

V.Mises [MPA]

Exterior shell thickness [mm]

Max

imum

V. M

ises

[MPa

]

*Interior shell thickness is constant =46.5mm



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253545556575

2.743

2.057

1.559

1.3671.2271.154

Max. deformation [mm] at different exterior shell thicknesses

Deformation (mm)

Exterior shell thickness [mm]

Max

. def

orm

ation

[mm

]

*Interior shell thickness is constant =46.5mm


Effect of interior shell thickness

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Effect of interior shell thickness

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60 50 46.462 40 30 20

1.2571.271

1.291

1.331

1.411

1.5003

Max. Deformation [mm]

Max. Deformation [mm]

Interior shell thickness [mm]

*constant exterior shell thickness = 65mm

60 50 46.462 40 30 20

112.19 113.03 114.07118.38

134.4142.6

V.Mises [MPa]

V.Mises [MPa]

Interior shell thickness [mm]

*constant exterior shell thickness =65mm


Effect of different shell thickness configurations

• Considering a reasonable “fin” thickness configuration of (25, 20, 15), I took 4 models of the entire lattice, each with different exterior and interior shell thicknesses:

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Change of dimensions Exterior shell [mm] Interior shell [mm]

Original 75 46.5

Moderate 60 40

Optimal ? 50 30

Extreme 35 20


Effect of different shell thickness configurations

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Original- 46.462int, 75ext

Conservative- 40int, 60ext

Optimal (?)- 30int, 50ext

Extreme- 20int, 35ext

110.92

127.56

149.02

180.58

V.Mises [MPa]V.Mises [MPa]

Original- 46.462int, 75ext

Conservative- 40int, 60ext

Optimal (?)- 30int, 50ext

Extreme- 20int, 35ext

1.4862

1.7906

2.2291

2.9324



Issues to be addressed What key areas should be modified next?

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•The exterior shell thickness at both the 3 & 9 o’clock positions may be increased.

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•The exterior shell thickness at both the 3 & 9 o’clock positions may be increased.

•The thickness of certain “fins” in the internal modules may be increased in order to sufficiently increase their compressive strength.

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Conclusions Accounting also for construction issues etc., optimum values (for the moment) look like • 50mm for outer shell, • 30mm for inner shell and • A fin thickness going from 14mm thickness inside smoothly to 26 mm at the

outside,

N.B. These values correspond to a fraction of ca. 5,5% of the total surface of a tungsten plate (and thus is lost for physics).

27 August, 2009

Pure Tungsten HCal : ‘staircase’ design

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