碳纤维与铝合金螺栓连接拉伸失效仿真研究

Simulation Research on Tensile Failures of CFRP and Aluminum Alloy Bolted Joint

通过有限元软件ABAQUS中Explicit模块建立碳纤维增强树脂基复合材料(CFRP)与铝合金螺栓连接接头的有限元仿真三维模型,并进行了相对应的单钉单剪拉伸试验研究。结合试验和仿真结果,获得了螺栓连接接头在单轴拉伸载荷下的损伤失效模式。铝合金失效基于延展性(Ductile)金属失效准则,CFRP失效准则基于Hashin准则,可以表现复合材料在纤维拉伸压缩、基体拉伸压缩、法向分层拉伸压缩和纤维与基体剪切模式下的7种失效形式,复合材料起始失效后采用刚度折减规则实现刚度退化。结果表明,螺栓失效过程分为3个阶段,即线弹性阶段、CFRP损伤起始阶段、接头失效阶段。对比仿真和试验结果,以接头强度角度考虑,仿真结果与试验结果误差为6.3%,说明了有限元仿真模型的有效性。通过有限元仿真结果分析发现,在螺栓接头失效过程中,CFRP失效发生在基体拉伸和压缩模式以及法向分层压缩模式上,铝合金表现出了明显的延展性损伤形式。

Based on Explicit simulation environment of ABAQUS,the finite element simulation 3D model of CFRP-Aluminum alloy bolted joint was established,and the corresponding single nail and single shear tensile experimental research were carried out.Combined with the experimental and simulation results,the damage failure modes of the bolted joint under uniaxial tensile loading were obtained.The aluminum alloy failure was based on the Ductile metal failure criterion,the CFRP failure criterion adopted the Hashin criterion modified by Shokrieh,which can represent 7 failure modes of the CFRP in fiber tensile and compression,matrix tensile and compression,delamination tensile and compression,as well as fiber-matrix shear modes,and the stiffness degradation of CFRP was achieved after the initial failure of the CFRP using the stiffness reduction rule.The results showed that the bolted joint’s failure process was divided into 3 phases,the linear elastic phase,the damage initiation phase of the CFRP,and the failure phase of the bolted joint.Comparing the simulation and experimental results,the error between them was 6.3%when considering the strength of the joint,indicating the validity of the finite element simulation model.The analysis of the finite element simulation results revealed that during the failure of the bolted joint,the failure of the CFRP occurred in matrix tensile and compression failure modes as well as delamination compression failure mode,and the damage of the aluminum alloy exhibited significant ductility.