Computational evaluation of the effects of void on the transverse tensile strengths of unidirectional composites considering thermal residual stress

摘要

To analyze the effects of void on transverse tensile properties of composites considering thermal residual stress (TRS), finite element models with different distribution patterns and shapes for voids are established. Two different void modeling methods, with voids explicitly established and with voids modeled within elements, are compared first. For the method with voids explicitly established, circular, elliptical and arbitrary voids are considered. To reveal the effects of TRS, two different TRS analysis methods are evaluated. Results show that for the models without considering voids and TRS, the interface debonding is the dominant failure mechanism. After considering the voids, the effects of matrix damage on the crack initiation become more important. There are more variations in tensile strengths of models with voids explicitly established than those from the models with voids modeled within elements. It is also found that higher TRS values are obtained when the change of matrix properties with temperature is considered. After considering the TRS, the matrix damage contributes more to the crack initiation and the interface debonding is inhibited. Besides, the TRS results in thermal residual matrix plasticity around the void, which contributes to the premature initiation of crack around the void.