This paper deals with a three-dimensional model for thermal
stress-induced transformations in shape-memory materials. Microstructure,
like twined martensites, is described mesoscopically by a vector of internal
variables containing the volume fractions of each phase. We assume that the
temperature variations are prescribed. The problem is formulated
mathematically within the energetic framework of rate-independent processes.
An existence result is proved and temporal regularity is obtained in case of
uniform convexity. We study also space-time discretizations and establish
convergence of these approximations.
