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  • Elastic-Plastic behaviour of AlSiC metal matrix composite rod under combined tension and

    torsion loading

    by

    Padmanabhan Raghupathy, M.E.

    This thesis is submitted to Dublin City University a s the fulfilment of the

    requirement for the award of the degree of

    ' Doctor of Philosophy

    Supervisor, Professor M S J Hashmi, Ph D , D Sc ,

    Co-supervisor Dr B J MacDonald, Ph D

    School of Mechanical and Manufacturing Engineering Dublin City University

    Septem ber 2003

  • DECLARATION

    I h e r e b y ce r t i fy th a t th is m a te r ia l , w h ich I n o w s u b m i t for a s s e s s m e n t on the

    p r o g r a m m e o f s tudy l e ad in g to the aw ard o f D o c to r o f P h i lo s o p h y , is en t i r e ly my

    ow n w o rk and has no t been taken f rom the w o r k o f o the rs save and to the ex ten t

    tha t such w o rk has been c i ted and a c k n o w le d g e d w i th in the tex t o f m y w o rk

    S ig n e d D a te ^ ^

    P a d m a n a b h a n R a g h u p a t h y

    S tuden t ID 9 8 971255

    11

  • ACKNOWLEDGMENT

    I take this o p p o r tu n i ty to express m y g ra t i tu d e to all th o s e who gave me the

    p o s s ib i l i ty to c o m p le te this th es i s In pa r t i cu la r ,

    I am d e e p l y in d e b te d to m y s u p e rv i s o r P ro fe s s o r M S J H ashm i w hose help,

    s t im u la t in g s u g g es t io n s and e n c o u ra g e m e n t s h e lp e d m e in all the t im e o f this

    r e s ea rch for and w r i t in g o f this thes i s

    I w is h to th a n k m y c o - s u p e rv i s o r Dr B ryan J M a c D o n a l d for h is va luab le

    su g g e s t io n s and g u id a n ce in u s ing the f in i te e l e m e n t too l A N S Y S and for c lose ly

    lo o k in g at this th es i s for co r rec t io n s and s u g g es t io n s for im p ro v e m e n t

    I w ish to th a n k Dr H a r ry E s m o n d e , Dr Paul Y o u n g and D r D e rm o t B rab az o n

    for the i r t im e ly he lp in the l a b o ra to ry and v a lu a b le su g g e s t io n s

    I th a n k Dr Jo se p h S tokes for his a s s i s tance in t a k in g S E M p h o to g ra p h s

    I w o u ld l ike to th a n k all m y c o l leag u e s in the Schoo l o f M e c h a n ic a l and

    M a n u f a c t u r in g E n g in e e r in g , in pa r t i cu la r , Be la l , N u n , D av id , P inak i , Tar ique ,

    Toan , H as sa n , A n th o n y , M a h f i z u r R a h m a n and R a s h id , for the i r help, s u ppo r t

    and v a lu ab le h in ts

    I am g ra te fu l to M ess r s Chr is C rouch , K e i th H ick ey , J a m e s Barry , M ar t in

    Jo h n so n , M ich ae l M a y and L iam D o m ic a n for all the a s s i s t a n c e g iven to me p r io r

    and d u r ing e x p e r im e n ta t io n

    E sp e c i a l l y I w o u ld l ike to g ive m y spec ia l th a n k s to m y w ife P r iya w h o se pa t ien t

    love enab led m e to c o m p le te th is w ork

    R P a d m a n a b h a n

    111

  • To my mother Hemalatha andfather Raghupathy

    IV

  • ABSTRACT

    M ost machine components and structural members are subjec ted to complex loading

    condi t ions dur ing service Typical complex loading condi t ions can be observed in the

    case o f a bolt W hen a bolt is t ightened to bring machine components together,

    s tresses such as tensi le stress (clamp load/area) , and tors iona l or shear s tresses

    (proport ional to applied torque) are developed in the shank and bolt threads To

    simpli fy the complex relat ionship be tween t ightening torque, fr ict ion co-eff icient and

    the pre load in the fastener, a circular rod is chosen to represen t the problem

    Inves t igat ions were carr ied out to determine 1) how the external tensile load affects

    the magnitude o f the ini t ial ly applied torque, and 11) how applicat ion o f torque affects

    the ini tially applied axial load or pre load in a spec imen in elast ic-plast ic range

    A p r e l i m i n a r y s tudy on c o p p e r s p ec im en s was u n d e r t a k e n to ga in k n o w led g e

    abou t e l a s t i c -p l a s t i c b e h a v i o u r u n d e r c o m b in e d t e n s io n and to r s io n load ing

    V ar io u s c o m b in a t io n s o f c o m b in e d t e n s io n and to r s io n load ing c o n d i t io n s were

    ap p l ied on the sp e c im e n s to e s tab l i sh the p r o p e r f u n c t i o n in g o f a r e c o m m is s io n e d

    t e n s io n - to r s io n m a c h in e and a d e d ica te d Lab V IE W p ro g ra m

    E x p e r im e n ta l i n v e s t ig a t io n s on A lS iC M M C rod sp e c im e n s revea l tha t the rod

    can sus ta in c o m b in e d ax ial load and to rque w e l l b e y o n d the c o m b in e d ini t ial

    y ie ld cu rve W h e n the sp e c im e n is su b je c t e d to an in i t ia l ax ial load or to rque

    fo l l o w e d b y to rq u e or ax ia l load re spec t ive ly , the s u b s e q u e n t load or to rque

    b e c o m e s d o m i n a n t in d e s c r ib in g the e l a s t i c -p l a s t i c b e h a v i o u r o f the s pec im en

    The in i t i a l load or to rq u e in the sp e c im e n does n o t a f f ec t the s u b s e q u e n t to rque

    or load ca r ry ing c a p a c i ty o f the spe c im e n

    A sp e c im e n su b je c t e d to a co n s ta n t r e la t iv e e x t e n s io n and ang le o f tw is t can

    sus ta in the c o m b in e d ax ial load and to rq u e w e l l b e y o n d the c o m b in e d ini t ial

    y ie ld cu rv e It is a p p a re n t tha t the sp e c im e n ca r r ie s r e l a t iv e ly h ig h e r axial load

    w h en the lo a d - to rq u e pa th is c lo se r to the ax ial load axis S imi la r ly , the

  • sp e c im e n car r ies re l a t iv e ly h ig h e r to rque w hen the lo a d - t o r q u e pa th is c lo se r to

    the to rq u e axis

    In a dd i t ion to the ex p e r im e n ta l in v e s t ig a t io n , a c o m p re h e n s iv e f in i te e l em en t

    m o d e l l i n g o f c o m b in e d tens ion and to r s ion lo a d in g o f a m ode l was u n d e r ta k e n

    tha t inc ludes bo th g e o m e t r i c as well as la rge d e fo r m a t io n ef fec t s for c ap tu r ing

    ax ial and shea r s t resses

    A m e t h o d o lo g y for the f in i te e l e m e n t ana lys i s o f s o l id rods u n d e r c om bined

    te n s io n and to r s ion loads was d e v e lo p e d T he n u m e r i c a l m o d e ls have

    s u c c e s s fu l ly c a p tu r e d the bas ic f ea tu res o f the e l a s t i c -p l a s t i c r e s p o n s e o f the

    A lS iC m e ta l m a t r ix co m p o s i t e and d e m o n s t r a te d the e f fec t o f pa r t i c le inc lus ion

    in the overa l l f low p ro p e r t i e s o f the co m p o s i t e , w h i le d e m o n s t r a t in g some

    l im i ta t ions

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    LIST OF FIGURES

    Description

    Elastic-plastic state o f a structural member

    Schematic diagram o f the experimental setup

    Components of tension-torsion test machine

    Controller and Power supply rack

    Axial load transducer calibration plot

    Torque transducer calibration plot

    Angular position transducer calibration setup

    Angular position transducer calibration plot

    LVDT calibration setup

    LVDT calibration plot

    Wheatstone bndge

    Strain gauge alignments with the axis o f the specimen

    AlSiC rod specimen fixed in the machine gnppers for testing

    Degreasing with solvent

    Abrading with silicon carbide paper

    Burnishing layout lines

    Applying conditioner to specimen surface

    Removing neutraliser with gauge sponge

    Modular 600 system - Transducer signal amplifier

    Input/Output connector boards for Device 1 and Device 2

    Lab VIEW front panel construct

    While Loop and Sequence Structure

    Case Structure

    Copper Model representing the gauge length and the extended volume

    Multi Linear Material Model used for Copper Rod Model

    Distribution of Silicon Carbide particles in Aluminium matrix

    V ll

  • Fiqure No

    Description Page No

    4 25 Model representing Silicon carbide particles and the extended volume 127

    4 26 Bilinear Material Model for Aluminium matrix 128

    5 1 Offset Strain in determination of Mechanical Properties 131

    5 2 Axial Stress-Strain Curve for Copper Rod 158

    5 3 Axial Stress-Axial Strain Curve for Copper Tube 159

    5 4 Axial Stress-Axial Strain Curve for AlSiC MMC Rod 160

    5 5 Axial Stress-Axial Strain Curve for AlSiC MMC Tube 161

    5 6 Shear Stress-Shear Strain Curve for Copper Rod 162

    5 7 Shear Stress-Shear St