航空复材电磁感应焊接过程及焊接强度

Electromagnetic induction welding process and welding strength of aeronautical composite materials

基于电-磁-热多场联合仿真方法建立电磁感应焊接数值模型,模拟电磁感应焊接过程;通过Cohesive单元及二次名义应变失效准则,分析碳纤维增强复合材料(Carbon fiber-reinforced polymer,CFRP)层合板电磁感应焊接强度;研究CFRP层合板搭接长度及聚醚醚酮(PEEK)胶粘层厚度对焊接强度的影响,并通过单搭接试验验证计算结果。结果表明,在搭接长度为12.5 mm,厚度为0.5 mm的条件下,感应焊接层合板温度最高为385.7℃,试验结果为372.5℃,数值结果与试验结果的误差为3.5%;在拉伸过程,焊接接头端部首先发生破坏,接头拉伸破坏为纤维抽离破坏、剥离破坏及基体内聚破坏共同作用产生;CFRP层合板的焊接强度与层合板搭接长度没有明显的相关性;PEEK胶粘层断裂类型为张开型与滑移型混合破坏,PEEK胶粘层厚取值为1 mm时,抗剪强度计算结果为5.97 MPa。

A numerical model of electromagnetic induction welding is established based on the electro-magnetic-thermal multi-field co-simulation method to simulate the welding process.The welding strength of CFRP layer is analyzed by the Cohesive element and the secondary nominal strain failure criterion.The effects of the lap length of CFRP laminates and the thickness of PEEK adhesive layer on the welding strength were studied,and the simulation results were verified by single lap test.The results show that the temperature of the welded laminate is up to 385.7℃,the test result is 372.5℃under the condition that the lap length is 12.5 mm and the thickness is 0.5 mm.The error between simulation results and test results is 3.5%.During the stretching process,the end of the welded joint is first damaged,and the tensile failure of the joint is caused by fiber pull-out failure,peeling failure and matrix cohesion failure.There is no obvious correlation between the welding strength of CFRP laminates and the lap length of laminates.The fracture type of PEEK adhesive layer is a mixed failure of open type and slip type.When the thickness of PEEK adhesive layer is 1mm,the calculated shear strength is 5.97 MPa.