CREEP CONSTITUTIVE MODELING OF AN ALUMINUM-ALLOY UNDER MULTIAXIAL ANDCYCLIC LOADING

A constitutive model is developed to characterize creep response of po lycrystalline metals. The model is based on the effective stress conce pt and back stress is utilized as an internal variable. A memory aspec t is incorporated in the model to account for the previous maximal str ess as a result of dislocation related micromechanisms. The model is u sed to predict the creep potential of an aluminum alloy under multiaxi al and cyclic loading. The predicted results are compared with the ava ilable experimental results on an aluminum alloy (2618-T61). The assoc iated six basic model parameters are evaluated by using an optimizatio n technique, called 'Box Algorithm'. These model parameters are then u sed to predict some unoptimized experimental data sets. The influence of multiaxial and cyclic loadings is investigated in detail for the se lected aluminum alloy. Overall, excellent correlations are observed. C opyright (C) 1996 Elsevier Science Ltd