多层多向层联三维机织复合材料的拉伸性能

设计制备了3种不同结构的多层多向层联三维机织复合材料(M3DAWC)，利用非接触式全场应变测量系统和SEM对其拉伸性能进行了研究。研究表明，织物结构对M3DAWC的宏观力学行为有重要的影响，沿0°方向拉伸，破坏模式随着斜向纱体积分数的增加，从齐口破坏演变为斜向纱的抽拔失效，沿90°方向拉伸，破坏模式基本一致，表现为斜向纱的抽拔和滑脱。同时，斜向纱体积分数对M3DAWC的拉伸强度和拉伸模量也有显著影响，沿0°方向拉伸，随着斜向纱体积分数的增加，拉伸强度和拉伸模量逐渐减小，沿90°方向拉伸则表现出相反的变化规律。 

Tensile properties of multilayer multiaxial interlock 3D woven composites

Three kinds of multilayer multiaxial interlock 3D woven composites (M3DAWC) were designed and prepared. Digital image correlation system (DIC) and SEM were employed to study the tensile properties of these composites. The results show that the fabric structure has significant effects on the mechanical behavior of M3DAWC. In 0° loading direction, with the increase of the bias yarn volume fraction, the failure mode changes from the neat damage to bias yarn withdrawal. The failure mode exhibits similar trends with that of 0° when the specimens were stretched along 90°, which are pull-out and slippage of the bias yarns. Meanwhile, the volume fraction of the bias yarn also has a significant influence on the tensile strength and modulus of the M3DAWC. In 0° loading direction, the tensile strength and modulus gradually decrease with the increase of bias yarn volume fraction. However, the tensile strength and modulus show an opposite pattern in 90° loading direction.