纤维增强复合材料冲击失效的二元模型分析

为了分析纤维增强复合材料在冲击载荷作用下的损伤破坏问题，提出一种基于二元模型的有限元方法. 将复合材料分为纤维束和等效介质2部分，根据它们的受力变形特点，分别采用杆单元和三维实体单元进行模拟，通过多点约束将2种单元集成为二元模型. 同时，对这些单元分别选用合适的失效准则模拟冲击作用下的损伤失效过程，并通过用户子程序VUMAT编程实现. 采用该方法对三维正交机织复合材料靶板的弹道侵彻过程进行仿真分析，结果表明：得到的子弹剩余速度与文献中的实验值和仿真结果较吻合，该二元模型和方法在纤维增强复合材料冲击破坏分析中具有较高的计算精度和效率.

Binary model analysis of impact failure of fiber reinforced composites

In order to analyze impact failure of fiber reinforced composites, a finite element technique based on binary model was proposed. The composites was partitioned into tows and an effective medium. According to their deformation characteristics, the tow and effective medium were respectively modeled with truss and 3D brick elements. Multi-point constraints were introduced to assemble a binary model from the two kinds of elements. Furthermore, suitable failure criteria for these elements were chosen to model the damage-to-failure process subject to impact. They were coded into the user's subroutine VUMAT. The present method was applied to simulation of ballistic penetration of 3D orthogonal woven composite target. The results of residual velocities agree well with those from corresponding experiments and simulations in references. It shows that the binary model and computation method have high accuracy and good effectiveness for impact failure analysis of fiber reinforced composites.