Influence of residual stress on the elastic-plastic deformation of composites with two- or three-dimensional randomly oriented inclusions

Based on the secant moduli framework with second-order moment of stress and the elastic micro-mechanical method proposed by Ponte Castaneda and Willis, a micro-mechanical method is proposed to consider the effects of thermal residual stress on the elastic-plastic deformation of composites. The micro-structural parameters like the volume fraction, shape, orientation, and distribution of inclusions are taken into account, and their influences on the macroscopic properties of the composites in the presence of thermal residual stress are analyzed. The computed results show that the presence of thermal residual stress induces asymmetric behavior in tension and compression. This depends intimately on the micro-structural parameters of the composite. Finite element calculations are also performed to predict the secant thermal dilatation coefficient and stress-strain relations in tension and compression for unidirectional composites. The proposed analytical method is found to compare favorably with the finite element results.