Nonlinear viscoelastic and viscoplastic constitutive equations with growing damage

摘要

Nonequilibrium thermodynamics, rate-processtheory, viscoelastic fracture mechanics and variousexperimentally-motivated simplifications are used to developconstitutive equations that account for effects of viscoelasticity,viscoelasticity, growing damage and aging. Their form is moregeneral than previously developed by the author, and allows forrelatively general tensorial effects of damage. Some importantspecial cases are then covered, with emphasis on viscoelasticity.Evolution equations for the damage expressed in terms ofinternal state variables (ISVs) are discussed, comparingformulations using scalar ISVs and tensor ISVs. Finally, someexperimental support for the theory is described. An Appendixillustrates the theory for an aging, linear viscoelastic materialwith growing cracks.