THERMOELASTICITY AT CRYOGENIC TEMPERATURES

A theory of thermoelasticity is developed which is suitable for application at cryogenic temperatures. The thermodynamic functions are so chosen as to give correct predictions with experimental findings of second-sound wave speeds in NaF, in the temperature range 8-20 K and in Bi, in the temperature range 1-4 K. After the non-linear theory is presented, a linearized theory is developed. A uniqueness theorem is provided for the linearized theory on an unbounded domain. The question of a half-space heated on its boundary is addressed and, in particular, the question of transverse elastic wave propagation is studied. Finally, a simplified theory in which only unidirectional solutions are allowed is examined.