Effects of thermal residual stress on transverse tensile strength of unidirectional carbon fiber reinforced epoxy composites considering void

To reveal the effects of manufacturing induced thermal residual stress(TRS) on the transverse tensile response prediction of carbon fiber reinforced epoxy composites, a representative volume element (RVE) generation method based on the random perturbation method was developed and RVE models which are more similar to the real microstructure were established. With periodical boundary conditions and the constitutive models of the constituents (fiber, matrix and interface), the thermal residual stress and progressive damage response of the models can be predicted under the thermal and mechanical loading conditions respectively. From the results, it can be found that the manufacturing process induces compressive stress in the matrix between two adjacent fibers and tensile stress around the voids along the loading direction. For the RVE models without voids, it is the interface debonding that contributes to the crack initiation and the thermal residual stress between two adjacent fibers increases the predicted strengths. The crack of the RVE models with voids all initiates from the matrix around the void and the manufacturing induced residual tensile stress around the void along the loading direction would contribute to the decrease of the predicted strengths from RVE models with voids. For the RVE models with different void sizes, with the increase of the void size, the failure strength decreases, and the thermal residual stress weakens the effects of void size on strength reduction. For the RVE models containing elliptical voids with different aspect ratios, the thermal residual stress would enhance the effects of aspect ratio on the strength reduction. © 2019, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.