Thermodynamics of perfect elastic fluids

A simple non.equilibrium thermodynamics is developed and a particular example is studied. The theory is formulated to describe a viscoelastic fluid, capable of finite deformation, which need not be locally in or near a state of thermodynamic equilibrium. This fluid may support shear stresses only when away from local thermodynamic equilibrium _ A notion of time-temperature superposition is contained in the formulation of the constitutive equations. Conservation of energy is obeyed and the second law of thermudynamics is satisfied as a consequence of simple requirements on the constitutive relations. In an adiabatic isochoric motion the temperature increases when work is done on the material and decreases when the material does work. For given volume and temperature, e ntropy decrea ses whe n the mate rial is deformed from equ il ibrium . It is s hown in what general way viscos it y depends upon te mperature . For infinites imal s train, the special form of the stress-s train relations are derived in order to de termine how t.e mpe rature and t ime-t e mperature supe rpos ition e nte r in thi s case.