Influence of cracks and voids on the responses of composites

Abstract

In this paper, numerical study on influence of parameters related to cracks and voids on the responses of the composites under tension, compression, and shear deformation is conducted by extended finite element method (XFEM). Under tension, the maximum stress of composites changes less than 5% when crack orientation, fiber orientation, and void distance change. The maximum averaged stress could differ by 10% when the crack location and crack length change. In the multi-crack composites, there is difference by 10% in maximum stress due to relative crack location. Under shear deformation, crack orientation affects the maximum averaged shear stress significantly when compared to the same composites under tension. The difference of maximum averaged shear stress is more than 15% when fiber orientation changes. The void distance results in 5% difference on the maximum stress of composites. In the multi-crack composites, the relative crack location could result in 10% difference in maximum averaged shear stress. Crack length also could result in significant difference in maximum stress of composites under shear deformation. Under tension and shear deformation, one crack is always the dominant crack and its propagation path determines the strength of the multi-crack composites. Unlike in tension and shear deformation, single crack in the composites under compression doesn’t result in the failure of composites even when the strain is 0.03. That is, no geometric buckling occurs for the single crack composite under compression. Noticeable crack propagation starts in multi-crack composites under geometric buckling, which result from the existence of multi-cracks and their interaction in the composites.