BULK RESPONSE OF VISCOELASTIC SOLIDS

The dilatational response of polymeric solids is considered. Since such materials exhibit both instantaneous and equilibrium elasticity, as well as rate-effects, it is assumed that polymers can be characterized as finite linear viscoelastic solids and their dilatational behavior is described in terms of an instantaneous and equilibrium hydrostat. These functions represent the bulk response to hydrostatic loads applied over very short and very long time periods. A technique for determining these functions from quasi-static and ultrasonic wave propagation experiments is presented. The instantaneous and equilibrium hydrostats for PMMA are given as an example.