铁道客车焊接构架疲劳强度评估方法

铁道客车转向架构架作为典型的焊接结构,焊缝部位是疲劳失效的薄弱环节,对其焊缝位置的疲劳强度进行准确评估对构架的设计显得尤为重要.对比分析了焊接接头的3种有限元建模方式对焊缝部位应力的影响,建立了考虑焊缝和不考虑焊缝的构架有限元模型,参照UIC 515—4标准对构架的两种有限元模型分别施加模拟运营工况载荷,绘制了构架Goodman曲线,对比分析了两种建模方法的疲劳强度.结果表明:3种焊缝建模方法对应力分析结果有较大的影响;与考虑焊缝的构架有限元模型相比较,不考虑焊缝单元的构架有限元模型分析得到的疲劳强度结果安全系数较小,分散性较大,结果偏于保守.本文可以为铁道客车转向架构架的建模及评估方法为构架的设计提供参考.

Evaluation method of fatigue strength for welding bogie frame on railway vehicle

Since bogie frame is a typical welding structure,and weld line is the weakest part of fa-tigue failure,it is extremely important to evaluate its fatigue strength on welding position cor-rectly.First,a simple welding structure in three different modeling methods was established and the comparison analysis based on the results was presented.Second,two bogie frames with differ-ent details on welding position were modeled,and the results of two finite element models on simulative working conditions were carried out with reference to UIC 5 1 5—4 standard.Then,the fatigue strength evaluation and comparison of two bogie frames were carried out by using the modified Goodman curve.The result shows that the modeling method of weld j oints has a signifi-cantly influence on stress results.Using bogie frame model without welding line to assess fatigue strength inclines to safe side,which is feasible in engineering field.This paper can provide refer-ences for design and fatigue assessment of bogie frame.