Investigation on off-axial tensile properties of 3D braided composites considering void defects

3D braided composites have been increasingly applied in the aerospace, automotive, and other high-tech industries as primary load-bearing structures due to their excellent integrated performance. Evaluation on the failure behavior of 3D braided composites subjected to off-axial loading still remains a challenging topic. We present in this paper a meso-scale finite element (FE) model containing void defects for investigating the off-axial tensile behavior of 3D braided composites. The FE model is verified and the effects of porosity are discussed in on-axial tensile conditions, and then it is executed to predict the mechanical response in general off-axial tensile cases. The strength properties of 3D braided composites, and more importantly the progressive damage behavior under typical off-axial loadings, are analyzed in detail. It is found that the off-axial tensile strength and corresponding failure mode of 3D braided composites are mainly affected by the braiding angle of specimen. The proposed FE modeling provides an appropriate reference for the numerical study of void defects and off-axis load problems in other textile composites.