We will explain how this degeneracy allows for the existence of equilibrated striped domains and discuss a elastomer did not occur until 1981, commercial applications of nemaatic elastomers are still under development. Areas that show promise include MEMS devices, integrated optics, and artificial muscle. Our research on nematic elastomers is part of multidisciplinary effort involving experimentation and synthesis. However it never happens in the properly posed physical problems. It is proved that continuous deformations in the region of softening are unstable.
Instability leads to a dynamical process even in the case of quasistatic external loading.
Deformations corresponding to the descent part of the stress-strain diagram are localized at the surfaces, lines or points depending on the dimension of the problem under consideration. Localization of deformations produces unloading that provokes propagation of shock waves of unloading and secondary hardening. The fundamental laws of conservation and balance combined with the initial and boundary conditions constitute well-posed mathematical problem. As an illustrative example the problem of quasistatic displacement controlled stretching of an elasto-plastic bar with partial softening is considered. In this case the post critical process is also dynamic but the governing equations are hyperbolic and problem is well posed even for deformation on the descent segment.