轨道车辆复杂承载焊接结构的抗疲劳设计

Anti-Fatigue Design of Complex Load-Bearing Welded Structure of Rail Vehicles

从焊接接头疲劳的独有特征出发,基于结构应力研究轨道车辆复杂焊接结构的抗疲劳设计方法。利用标准中典型焊接接头疲劳试验数据和有限元分析,研究焊缝余高、被焊接部件坡度、承载方向及焊缝熔透等对焊接接头应力的影响。结果表明:这些影响因素最终都体现到焊接接头传力路径上的刚度变化,致使焊接接头应力增大或出现应力集中现象,进而降低了焊接接头疲劳强度。在BSEN 13749:2011规定的载荷作用下,分析某货车转向架焊接构架焊接接头结构应力的变化规律,识别出构架应力集中发生部位。提出以缓解设计阶段应力集中为目标的承载焊接结构抗疲劳设计原则,并基于这些原则对构架局部进行的优化,有效地缓解了焊缝的应力集中。

Starting from the unique characteristics of welding joint fatigue,the anti-fatigue design method of the complex welded structure of the rail vehicle is studied based on the structural stress.The effects of weld reinforcement,the slope of welded component,load bearing direction and weld penetration on the joint stress are studied by using fatigue test data and finite element analysis method of typical welded joints in the standard.the results show that these interfering factors are ultimately reflected in the change of joint stiffness on the force transmission path of the joint,resulting in the increase of joint stress or stress concentration,and the reduction of fatigue strength of the joint.Under the load given in EN13749-2011 standard,the change rule of structural stress of a freight train bogie welded frame joint is analyzed,and the position of stress concentration is identified.The basic principle of anti-fatigue design of load-bearing welded structures is proposed to alleviate the stress concentration in the design stage.Based on these principles,the local optimization of the frame can effectively alleviate the stress concentration of the weld.