Influence of Fiber Distribution and Interfacial Strength on Transverse Compressive Strength of Unidirectional Composites

纤维分布与界面强度对复合材料横向压缩性能影响分析

School of Aeronautics, Northwestern Polytechnical University, Xi’an, 710072, China

Received: 20 June 2018

Abstract

The representative volume element(RVE) of the computational micromechanics is established with random fiber distribution being generated by random sequential expansion algorithm. The plasticity of matrix and interfacial decohesion are simulated by using Drucker-Prager model and cohesive zone model respectively. The effects of the random fiber distribution and interfacial strength on the transverse compressive strength of unidirectional composites are analyzed. The results show that the random fiber distribution is a factor to cause the instability of the transverse compressive strength. Meanwhile, the matrix plastic shear damage and non interfacial damage is dominated in compression failure. Therefore, the RVE model without interface element adopted can clearly predict the compressive strength and the damage process of unidirectional composites, which contributes to simplify the modeling without considering the value of interfacial parameters.

摘要

建立了纤维随机分布代表性体积单元微观力学模型，采用随机扩张算法生成纤维随机分布模型，微观有限元模型中采用内聚力单元和Drucker-Prager弹塑性准则分别对界面和基体的力学行为进行描述，分析研究了纤维分布形式与界面强度对复合材料横向压缩性能的影响。结果表明纤维随机分布是引起复合材料横向压缩强度不稳定的一个因素；基体剪切塑性损伤而不是界面损伤在复合材料横向压缩破坏过程中起主导作用，因而采用无界面单元模型可以简化建模、不需要考虑界面强度取值，并能很好地预测复合材料横向压缩强度与压缩损伤破坏形貌。