A virtual power format for thermomechanics

It is shown that a virtual power format slightly more general than usual may be employed to deduce all balance and imbalance laws of thermomechanics. An essential role is played by the notion of thermal displacement; the basic balance laws turn out to be those for momentum and entropy. In consequence of these balances and of two axioms of thermodynamical nature-namely, conservation of internal action in cyclic processes and dissipative nature of ordinary processes-balance of energy and inbalance of entropy are arrived at.