Analysis of tensile properties for composites with wrinkled fabric

During the fiber preform loading process of resin transfer moldings (RTMs), fabric layers can be wrinkled in the preform, which affects the quality of the composite. This study considers several wrinkled models with different wrinkled lengths (LW) and different numbers of wrinkled layers in the preform. To study the effects of wrinkling on tensile properties, two matrix materials with different moduli are used to enhance understanding. It is found that the tensile moduli of wrinkled models are lower than those of the normal model, for the same fiber volume fraction (Vf). The effects of wrinkling on the tensile modulus increase with the number of layers as well as Vf. In addition, the effect of wrinkling with a low-modulus matrix on the tensile modulus is larger than that with a high-modulus matrix in the composite. Based on the failure modes and the stiffness of materials, the failure mechanisms of wrinkled models can be separated into two regimes as a function of wrinkled length, LW, depending on the critical wrinkled length (LWC)