碳纤维/环氧树脂复合材料缠绕接头拉伸失效机制

通过试验及数值模拟对碳纤维/环氧树脂复合材料缠绕接头轴向拉伸失效机制进行研究。基于ABAQUS有限元软件，通过连续介质损伤模型及内聚区模型，分别对碳纤维/环氧树脂复合材料缠绕接头各部件及界面进行模拟，编写用户自定义材料子程序(UMAT)，建立复合材料的渐进损伤模型，最终得到碳纤维/环氧树脂复合材料缠绕接头的应力分布和载荷-位移曲线，并与试验结果对比确定结构的失效机制。结果表明:有限元分析所得碳纤维/环氧树脂复合材料缠绕接头损伤部位及失效模式与试验吻合，失效载荷与试验值相差较小，证明仿真分析方法的有效性。通过对比失效模式发现，拉伸载荷作用下，链环是主承力部件，其弧形端部是应力集中处，纤维断裂即从此处开始发生并向外扩展，导致链环断裂及整体结构破坏。 

Tensile failure mechanism of carbon fiber/epoxy composite winding joint

The axial tensile failure mechanism of carbon fiber/epoxy composite winding joint was studied by means of experiment and simulation. Based on ABAQUS, the continuum damage model and cohesive zone model were used to simulate each part and interface of the carbon fiber/epoxy composite winding joint, respectively. The progressive damage model of the carbon fiber/epoxy composite was established by writing user-defined material subroutine(UMAT). As a result, the stress distribution and load-displacement curve of the carbon fiber/epoxy composite winding joint were obtained and the failure mechanism of the structure was determined by comparison with the experimental results. The results show that the calculated damage position and failure modes of the carbon fiber/epoxy composite winding joint agree well with the experimental results, and the difference between the calculated value and test value of the failure load is small, which proves the validity of the simulation analysis method. By comparing the failure modes, it is found that under tensile load, the loop plies are the main bearing component, and the curved end of which is the position where the stress is concentrated. The fiber fracture starts from here and gradually spreads outward until the loop plies fracture, which leads to the structural damage.