玻璃钢头罩粘接密封胶应力校核及失效分析

Stress verification and failure analysis of adhesive sealant for FRP hood

通过粘接试验及有限元计算,研究了轨道车辆玻璃钢头罩密封胶失效原因,提出了优化改进措施。结果表明:粘接胶、密封胶的弹性模量差异会导致密封胶优先承载,引起密封胶疲劳失效;长期作用的4 mm松弛变形未导致粘接接头剪切强度的降低,头罩、车体允许的装配尺寸公差可按4 mm控制;光照、湿热环境会导致胶黏剂表面老化失效,应适当提高外侧密封胶的检修频率,同时选用更耐候的胶黏剂。

By means of adhesive test and finite element calculation,the failure cause of the sealant of FRP head cover on rail vehicle is studied,and the optimization and improvement measures are put forward.The results show that the difference in the elastic modulus between adhesive and sealant could lead to the load bearing of sealant in the first place and consequently a fatigue failure of the sealant.The long-term relaxation deformation of 4 mm does not result in reduction of the shear strength of the adhesive joint,and the allowable assembly tolerance of the head cover and the car body could be controlled by 4 mm.Light,hot and humid environment could lead to the aging failure of the adhesive surface,and the maintenance frequency of the outer sealant should be appropriately increased,while a more weather-resistant adhesive should be selected and used.