Elastic–plastic bending analysis of beams with tension–compression asymmetry: bimodular effect and strength differential effect

Abstract

The tension–compression asymmetry is a basic mechanical property of materials themselves, which results in differences in elastic constant, yield strength, creep and fatigue. Among them, bimodular elastic effect and strength differential (SD) effect in plastic yielding will influence the whole elastic–plastic response. Existing studies have focused either on bimodular elastic effect of structures or on SD effect of materials, and few of them have combined the two effects. In this study, we theoretically analyze, for the first time, the elastic–plastic bending behavior of beams with the bimodular and SD effects, including loading and unloading process. The comparisons with our numerical simulation results and others’ experimental results validate the analytical solution obtained. The results indicate that during loading, the ratio of plastic limit bending moment to elastic limit bending moment is greater than known 3/2 and during unloading, the bending moment required by reverse yielding is greater than twice of elastic limit bending moment. The modulus ratio and yield strength ratio play an important role in elastic–plastic analysis and their relative magnitude determines whether the tensile edge yields first or the compressive edge. These results may help design optimal structural components in engineering.