A new three-dimensional analytical model to simulate microresidual stresses in polymer matrix composites

Abstract

Based on the energy method and the principle of minimum total complementary potential energy, a new three-dimensional analytical model is developed. A three-dimensional analysis is performed for a unit-cell representative volume element (RVE) consisting of a monofiber, a matrix, and an interphase region. The model is evaluated using the finite-element technique. In order to study the effects of neighboring fibers on the residual stresses, several microstructural finite-element models are considered. It is proved that the RVE used in the analytical model is suitable for predicting the thermal microresidual stresses in polymer composites. In comparison with the analytical model, the finite-element analysis presents a little higher residual stresses. According to the results of the analytical model, the interfacial shear stress reaches a maximum in the vicinity of fiber ends, while the finite-element analysis gives a maximum shear stress at composite ends. This is due to the edge singularity, which is not considered in the finite-element model. Although the interphase region affects the distribution of interfacial radial stresses only slightly, it has a significant effect on the maximum interfacial radial stresses at fiber ends.