Papers by Author: Tao Huang

Abstract: Mechanical tests have been conducted to understand compressive behavior of a plain weave C/SiC composite, especially to investigate the failure mechanism. The stress-strain curves of this composite show linear feature in compression. The specimens fail along a flat plane 13°~15° to the weave plane, running across four typical regions in the bulk: weft bundle, warp/weft interface, warp bundle, and inter-ply. According to the observed fracture route, four basic failure modes are schematically presented. Cracks form and develop in these areas along fiber/matrix interphase or within matrix, depending on the strength competition between interphase and matrix. The fracture mechanism reveals dependence of compress strength on matrix abundance between and within bundles. Based on the failure modes new method for compress strength prediction can be further investigated.

Abstract: Stitched laminates is a low-cost structure panels with carbon fiber face sheets, and through-the-thickness Kevlar stitching. Through-the thickness stitching is proposed to increase the interlaminar strength and damage tolerance of composite laminates. Tensile and shear experiment of stitched laminates at room temperature and in hygrothermal environment was carried out according to corresponding national standards. Experiment results indicate that the tensile and shear modulus and strength were much reduced by the stitching, especially in hygrothermal environment. Micrographs of fracture appearance showed that the exist of resin-rich area is the source of crack both in normal room temperature environment and hygrothermal environment. It is concluded that hygrothermal environment and initial crack in resin-rich area were prime reason for performance lost of stitched laminates.