On uniqueness of multiple-slip solutions in constrained and unconstrained f.c.c. crystal deformation problems (Q1091846)

Since 1975 Havner became one of the greater specialist in the domain of f.c.c. crystal deformation. Several of Havner's works, or his works with collaborators, are concerned with the physical conception of crystal hardening [see e.g. \textit{K. S. Havner} and \textit{S. A. Salpekar}, J. Mech. Phys. Solids 30, 379-398 (1982; Zbl 0496.73033) and 31, 231-250 (1983; Zbl 0512.73036). The ``simple theory'', according to the author, may be stated as follows: ``on the scale of gross plastic deformations representable within the framework of continuum mechanics, anisotropy of finite-distortional hardening and associated ``overshooting'' are related to and in part caused by the relative rotation of material and lattice''. In this work, the authors prove a modification of the simple theory of rotation dependent anisotropy with the scope to solve the problem of uniqueness of solution.