A multivariant micromechanical model for SMAs Part 2. Polycrystal model

An averaging scheme is developed to simulate the behavior of a polycrystall ine shape memory alloy (SMA) specimen using the Multivariant Micromechanics approach. An untextured polycrystalline specimen is assumed to be formed b y a number of randomly oriented single crystal grains. The previously devel oped Multivariant technique is used to model the response of each single cr ystal grain subjected to its stress field seen in the polycrystalline sampl e. Using spherical grains, the Eshelby-Kroner approach is used to formulate the interaction between grains and to determine the stress state in each i ndividual grain. This model successfully captures the basic features of SMA polycrystalline response to loading and temperature, in addition, comparis on is made to recent experimental data with fully triaxial load states. Rea sonable qualitative agreement is obtained and some issues related to crysta llography of the material model are addressed. (C) 2000 Elsevier Science Lt d. All rights reserved.