A note on Maxwell's relation in linear thermoelasticity (Q1090480)

By a Maxwell's relation in linear thermoelasticity the author means the relation: \(\underset \tilde{} M=-\underset \tilde{} N\), where \(\underset \tilde{} M\) is the stress-temperature tensor, and \(\underset \tilde{} N\) defines the internal energy density as a linear function of the strain tensor. He gives an ad hoc inequality involving the total and net internal energies, which is necessary and sufficient for the validity of the Maxwell relation.