考虑汽车车身涂装工艺影响的非平衡胶接接头强度

Influence of Automobile Body Coating Process on the Strength of Unbalanced Adhesive Joints

汽车轻量化的发展要求汽车采用更多的轻型材料取代传统的金属材料,而异种材料的连接就为结构胶接技术的应用提供平台。通过模拟汽车车身涂装工艺中环境温度和相对湿度的变化,采用韧性和脆性两种结构胶粘剂,分别对钢/铝和钢/碳纤维增强复合材料非平衡胶接接头的剪切强度进行环境影响研究。试验结果表明,汽车涂装环境对结构胶接接头的性能有着显著的影响,并且与胶粘剂自身性质有关。通过对不同工况接头的失效模式分析和对胶层的内聚力单元数值二维建模仿真,得到两种胶粘剂在涂装工况影响下胶层宏观力学属性和内部应力分布情况的变化趋势,并对碳纤维增强复合材料与相应胶粘剂材料表面参数的匹配问题进行研究。采用扫描电镜法对胶层失效表面进行样貌分析,探究相应宏观试验结果产生的微观原因。

The development of automobile lightweight requires more lightweight materials in vehicles replacing metallic materials and the structural adhesion technique provides a good option for joining dissimilar materials. The influence of environmental degradation on steel/aluminum and steel/CFRP adhesive joints is studied through simulating the variation of environmental temperature and relative humidity during automobile coating process and adopting both ductile and brittle adhesives. Experimental results reveal that adhesive joint behavior is greatly affected due to the automobile coating environment. Based on the comparison of different shear strength and the cohesive zone numerical modeling of the adhesive joints, the variation trend of different adhesives is obtained and the matching issues of CFRP and adhesive material parameters is analyzed. Through the analysis of scanning electron microscope on the fracture surface, the microscopic manifestation of the adhesive layer is analyzed to explain the macroscopic experimental results.