SIMULATION OF THE BEHAVIOUR OF FCC POLYCRYSTALS DURING REVERSED TORSION

Abstract Taylor-type polycrystal plasticity models with various single slip hardening laws are evaluated by studying the large strain behaviour of FCC polycrystals during reversed torsion. The hardening laws considered include the model of Asaro and Needleman (“Texture Development and Strain Hardening in Rate Dependent Polycrystals,” Acta Metall. (1985), 34 , 1553) as well as a power-law and an exponential version of that, and a more recent model by Bassani and Wu (“Latent Hardening in Single Crystals II. Analytical Characterization and Predictions,” Proc. R. Soc. Lond. (1991), A435 , 21). The material parameters for the various hardening laws are fitted to experimental compression data for copper and then used to predict reversed large strain torsion of tubes. Differences under “free-end” (axially unconstrained) or “fixed-end” (axially constrained) conditions between predictions and experimental observations are discussed in detail. In addition to the torque response, the Swift effects upon twist reversal are studied.

[1]  E. Giessen,et al.  Analysis of the inverse Swift effect using a rate-sensitive polycrystal model , 1993 .

[2]  John L. Bassani,et al.  Latent hardening in single crystals. II. Analytical characterization and predictions , 1991, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[3]  B. Adams,et al.  Unrecoverable Strain Hardening in Torsionally Strained OFHC Copper , 1990 .

[4]  V. Giessen,et al.  ON LARGE-STRAIN INELASTIC TORSION OF GLASSY POLYMERS , 1993 .

[5]  S. R. MacEwen,et al.  Effect of stress reversals on the work hardening behaviour of polycrystalline copper , 1986 .

[6]  E. Giessen,et al.  Analysis of elastic-plastic torsion of circular bars at large strains , 1991 .

[7]  L. Anand,et al.  Polycrystalline plasticity and the evolution of crystallographic texture in FCC metals , 1992, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[8]  W. Swift,et al.  Length Changes in Metals Under Torsional Overstrain , 1947 .

[9]  Length changes during large strain reverse torsion , 1996 .

[10]  M. Rubin,et al.  Analytical modelling of second order effects in large deformation plasticity , 1992 .

[11]  C. Laird,et al.  Latent hardening in single crystals - I. Theory and experiments , 1991, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[12]  V. Giessen,et al.  On the effect of plastic spin on large strain elastic-plastic torsion of solid bars , 1992 .

[13]  Lallit Anand,et al.  The process of shear band formation in plane strain compression of fcc metals: Effects of crystallographic texture , 1994 .

[14]  Reverse Torsion Testing for Material Modeling , 1993 .

[15]  L. Anand,et al.  An internal variable constitutive model for hot working of metals , 1989 .

[16]  A. Needleman,et al.  A tangent modulus method for rate dependent solids , 1984 .

[17]  J. Jonas,et al.  Large strain shear and torsion of rate-sensitive FCC polycrystals , 1990 .

[18]  K. S. Havner,et al.  A comparative study of hardening theories in torsion using the Taylor polycrystal model , 1996 .

[19]  A. Needleman,et al.  Analysis of large-strain shear in rate-dependent face-centred cubic polycrystals: correlation of micro- and macromechanics , 1989, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[20]  John L. Bassani,et al.  Plastic flow of crystals , 1993 .

[21]  The torsion texture of copper , 1950 .

[22]  J. Lipkin,et al.  Analysis of axial deformation response during reverse shear , 1991 .

[23]  Herbert F. Wang,et al.  Single Crystal Elastic Constants and Calculated Aggregate Properties. A Handbook , 1971 .

[24]  R. Asaro,et al.  An experimental study of shear localization in aluminum-copper single crystals , 1981 .

[25]  R. Asaro,et al.  Overview no. 42 Texture development and strain hardening in rate dependent polycrystals , 1985 .

[26]  L. Anand,et al.  Crystallographic texture evolution in bulk deformation processing of FCC metals , 1992 .