On Relating Inelastic and Redistributed Elastic Analyses Stress Distributions

Abstract

The classical lower bound theorem in plasticity states that the load required to create equilibrium stresses in a structure that are below yield will always be less than or equal to the collapse load. Recent advances in determination of lower bound limit loads involve repeated elastic analysis after systematic modification of elastic moduli. The intention is to obtain lower bound limit loads from stress fields that would progressively approach a state similar to one at plastic limit. The gradual transformation of statically admissible stress fields from elastic to limit state can be compared to various creep distributions corresponding to power-law creep indices ranging from one to infinity. This paper attempts to establish such one-to-one relation by using stress fields obtained from repeated elastic analyses.