ASME 1992 Nadai Lecture—Micromechanics of Inelastic Composite Materials: Theory and Experiment

Some recent theoretical and experimental results on modeling of the inelastic behavior of composite materials are reviewed. The transformation field analysis method (G. J. Dvorak, Proc. R. Soc. London, Series A437, 1992, pp. 311–327) is a general procedure for evaluation of local fields and overall response in representative volumes of multiphase materials subjected to external thermomechanical loads and transformations in the phases. Applications are presented for systems with elastic-plastic and viscoelastic constituents. The Kroner-Budiansky-Wu and the Hill self-consistent models are corrected to conform with the generalized Levin formula. Recent experimental measurements of yield surfaces and plastic strains on thin-walled boron-aluminum composite tubes are interpreted with several micromechanical models. The comparisons show that unit cell models can provide reasonably accurate predictions of the observed plastic strains, while models relying on normality of the plastic strain increment vector to a single overall yield surface may not capture the essential features of the inelastic deformation process.