On the Stress Analysis of Creeping Structures Subject to Variable Loading

Abstract

In earlier papers [13, 14] displacement and deformation bounds were derived for a structure composed of an elastic, perfectly plastic, time-hardening viscous material. Here the upper and lower work bounds are discussed for a body subject to cyclic loading. It is shown that the optimal bounds may be interpreted as the asymptotic states when the cycle time is very small and very large compared with a characteristic time of the material. The time scales which occur in practice are discussed, and a simple worked example is presented.