Creep Mechanics

In this book constitutive equations for the secondary and tertiary creep stage of anisotropic materials are formulated. To investigate the secondary creep behaviour the existence of a creep potential is presumed. It is established, that regarding to the theory of representation for tensor functions the creep potential hypothesis furnishes only restricted forms of constitutive equations even if a general creep potential is assumed in the anisotropic case. The creep process in its tertiary phase is characterized by a damage tensor. Some possible representations of constitutive equations involving (initial) anisotropy of the material (e.g. from rolling) and anisotropic creep-damage are discussed. The formulation of such equations is based upon theorems regarding tensor-valued tensor functions.