2.5D机织复合材料的渐进损伤与失效模拟

Progressive damage and failure simulation of 2.5D woven composites

为了研究典型2.5D机织复合材料的压缩性能,开展了复合材料单胞结构的经向和纬向压缩实验,并通过对材料编织结构的细观表征,建立了细观尺度的单胞有限元模型来模拟压缩载荷下单胞内部的变形及渐进失效过程。结果表明,2.5D机织复合材料在受压时表现出明显的非线性力学响应,材料沿经向的压缩模量和强度均高于纬向;经向压缩时材料的主要破坏模式有经纱的横向开裂、纤维束间的界面分层破坏、纬纱的压溃及基体的开裂,纬向压缩时出现的主要破坏模式是纬纱的压溃、纬纱纤维束的断裂及基体开裂;通过对比试验与有限元结果,认为所建立的细观有限元模型能够准确预测材料单胞在压缩载荷下的应力-应变响应,并且能够模拟编织结构中的损伤起始和演化过程。

Compression tests were carried out on the unit cell of a typical 2.5D woven composite to examine the compression performance. Meanwhile,a high fidelity meso-scale finite element model which was generated in term of the microscopic characterization of the woven architecture was adopted to investigate the internal deformation and progressive failure process of the unit cell. The results indicate that the 2.5D woven composite exhibits nonlinear mechanical response under both the warp and the weft compression,and the compression modulus and strength along warp direction are higher than those in weft direction;The dominate failure modes of warp compression contain transverse cracking of warp yarns,interface debonding between yarns,crushing of weft yarns and the pure matrix cracking;during the weft compression,the crushing and fracture of weft yarns as well as the pure matrix cracking are observed. Moreover,by comparing the experimental and simulation results,the proposed mesoscale model can well predict the stress-strain responses of the 2.5D woven composite under compression loads,as well as accurately simulate the damage initiation and evolution within the woven architecture.