基于细观有限元方法的复合材料横向力学性能分析

横向断裂是制约复合材料结构设计的关键点,传统细观模型因为不能充分考虑组分性能、体积分数和纤维形状及分布情况而不能有效预测材料横向力学性能。采用改进的随机序列吸收算法建立具有随机纤维分布的复合材料代表性体积单胞模型,考虑基体破坏和界面脱粘两种失效模式和固化过程中产生的残余应力,对模型在横向拉、压、剪3种载荷下的力学行为进行仿真计算。分析了不同界面强度对复合材料力学性能的影响规律。仿真结果与实验数据对比表明:横向模量预测误差在7%以内,压缩和剪切的强度误差在8%以内,结果一致性较好,表明该模型能够有效预测复合材料横向力学性能。

Analysis of Composite Transverse Mechanical Properties Based on Micromechanical Finite Element Method

Transverse fracture often occurs early in the loading history and is one of the key issues lim‐iting the composite structural design .However ,the mechanical behavior under transverse loading can not be represented by traditional micromechanical model w hich does not consider the influence of con‐stituent properties ,fiber volume fraction and fiber distribution .A new computational micromechanics finite element method ,which the microstructure was idealized as a random dispersion of parallel fibers embedded in the polymeric matrix using improved random sequence absorption algorithm ,was presen‐ted .The plasticity of matrix and interface decohesion of the composite were included in this model and the residual stress caused by the cooling of composite after the curing process was also taken into con‐sideration .The transverse tension ,compression and shear of composite were analyzed by the micro‐mechanical finite element method .Compared with the experiment results ,the prediction errors of transverse module were less than 7% ,and the transverse compression strength and shear strength were less than 8% .The results demonstrate that the method proposed here can be used to predict the composite transverse behavior .