T700轴向增强经编织物复合材料力学性能的模拟分析与试验研究

Simulation analysis and experimental research of mechanical properties of T700axial reinforced warp-knitted fabric composite

应用一种新型界面元模型研究了复合材料层间剪切损伤。通过引入双线性损伤准则和损伤演化,预报复合材料层间裂纹扩展。轴向增强经编织物复合材料由针织纱线引起的纤维变形(KYD)产生了富树脂区域,基于细观力学理论提出了一种新的研究轴向增强经编织物单胞模型受单向拉伸和剪切时KYD区周围应力分布的方法,得出了单胞在受载时首先在这一区域产生裂纹。对单轴向T700经编织物复合材料进行了三点弯曲性能和层间剪切性能试验测试,分析了经编织物复合材料的力学特性。分别模拟了弯曲性能和层间剪切性能试验,得出了最大预报载荷值与试验值误差小于10%,并基于有限元模型研究了复合材料面内损伤和层间裂纹扩展损伤机制。

A new type of cohesive zone model（CZM） was used to study the composite interlaminar damage in this article. The model consisted of the bilinear damage criterion and damage evolvement could accurately predict the delamination propagation. The resin rich zones were recognized a{ter impregnating referred to as knitting yarn induced fiber distortions （KYD） in the axial reinforced warp knitted fabric. A new method to study the stress distributing around the KYD region when the unit cell was extruding and shearing was descripted based on the micromechanics theory of composite materials. The distortion is recognized to be dominant for the crack damage initiation. Bending and interlaminar shearing mechanical properties of T700 unidirectional warp knitted fabric composite were tested. The discrepancy of the maximum strength between simulation and experiment about the bending and shearing is under 10%. The damage in laminates and interlaminar crack propagation damage were studied based on the finite element model.