Chengshi guidao jiaotong yanjiu (May 2024)
Study on Fatigue Performance of Stainless Steel Spot Welded Structures for Rail Vehicles
Abstract
Objective To enhance the fatigue resistance of stainless steel vehicle carbodies and obtain fatigue characteristic curves of spot welded joints, thereby guiding fatigue analysis and structural design of stainless steel spot welded rail vehicles, it is necessary to study the fatigue performance of stainless steel spot welded structures for rail vehicles. Method Summarizing the types of spot welded joints in an existing vehicle model, stainless steel resistance spot welding butt joint specimens and arc breakdown welding butt joint specimens are fabricated based on the characteristics of spot welded joints. According to the fatigue failure principles of spot welding and metal materials, finite element analysis and experimental methods are used to experimentally verify and compare the fatigue performance of stainless steel spot welded joints. Result & Conclusion ΔF-N curves for 12 different types of spot welded joints are obtained, through failure analysis, the cracking of the specimens originated from the surface of the heat-affected zone of the weld seam is detected, and the initiation of fatigue cracking is related to transgranular crack-like defects on the steel plate surface. The influence of welding type and plate thickness parameters on the fatigue life of joints is summarized: for the same plate thickness combination, selecting the arc breakdown welding method would result in a higher fatigue life of the joint; for joints with the same welding type, those with larger plate thickness demonstrate better fatigue performance. If the thickness of one plate is larger than the other in comparison to another type of joint, the one with a larger difference in plate thickness will have a longer fatigue life under low load amplitude. However, if a certain limit is exceeded, the one with a smaller difference in plate thickness will have a longer fatigue life.
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