A note on the thermo mechanics of elastic quasi crystals
In recent years, many papers have been published concerning the elasticity of quasi crystals. The present study has for main purpose to replace the proposed formulations into the framework of the modern thermo mechanics of continua. Two types of modelling are envisaged in small deformations, those inspired by the physical descriptions proposed by Bak on the one hand and by Lubensky and co workers on the other. While the first one fits well in a traditional variational formulation, the second one seems to be best accommodated in the frame of the thermo mechanics of internal variables of state, the newly introduced "phason" field being then interpreted as such a vector variable. The inclusion of these two models in the theory of configurational forces useful for the study of the expansion of defects frequent in such crystals and the possibilities of including the effects of nonlinear elasticity and plasticity are briefly discussed. Important symmetry conditions are however left aside.