ON THE INELASTIC BEHAVIOR OF SOLIDS .1. TWINNING

Recently, WINEMAN and RAJAGOPAL [1990] ''On a Constitutive Theory for Materials Undergoing Microstructural Changes,'' Arch. Mech., 42, 53 an d RAJAGOPAL and WINEMAN [1992] ''A Constitutive Equation for Nonlinear Solids which Undergo Deformation Induced Microstructural Changes,'' I nt. J. Plasticity, 8, 385, developed a theory that was particularly we ll suited to describing the inelastic behavior of polymeric materials. Here, we draw upon their ideas and generalize them to include a much larger class of materials. The versatility and efficacy of the theory are illustrated by studying the problem of twinning within the context of the theory. We find that the predictions of the theory are remarka bly close - both qualitatively and quantitatively with the experimenta l results of MADHAVA et al. [1972] ''Discontinuous Twinning during Ess entially Elastic Compression of Steel at 4.2K,'' Phil. Mag., 25(2), 51 9 and MADHAVA and ARMSTRONG [1974] ''A Constitutive Relation for Defor mation Twinning at High Strain Rates,'' in ROHDE, R.W., BUTCHER, B.M., HOLLAND, J.R., and KARNES, C.H., eds., Metallurgical Effects at High Strain Rates. Plenum, New York, 1974.