Experimental study on fatigue performance and damage model of aluminum alloy welding joints for high-speed train car body

In order to realize lightweight, security and comfort, the aluminum alloy profile becomes the first choice of the high speed train carbody. The fatigue experiments are carried on the typical welding joins such as butt, fillet, cruciform and lap joins. The fatigue limits and P-S-N curves are obtained. The non-linearity cumulative damage model is proposed taking loading sequences for consideration and the two-level loading experiments on butt and fillet joints are studied to verify the feasibility of the damage model. The fatigue life of carbody is predicted based on the proposed damage model and the online dynamic stress test results. The results show that the fatigue life calculated by non-linearity damage model is close to that by modified Miner law and 22% less than that by Miner law.