钢轨焊接接头的静弯试验有限元建模及受力分析

Finite element modeling and stress analysis for static bending test of rail welded joint

钢轨焊接接头的静弯试验是评定焊接工艺和接头性能的重要方法。基于静弯试验系统的结构特征,建立了包含双接触对的钢轨焊接接头静弯接触有限元模型,分析了单元尺寸和接触刚度等接触对参数对计算时间及计算结果精度的影响,优化确定出合适的单元尺寸和接触对模型参数,并通过对比已有文献数据,证明了模型的适用性。然后根据钢轨闪光焊接头的静弯检验标准,对钢轨轨头受压(正弯)和轨头受拉(反弯)时的应力分布进行了模拟计算,获得了钢轨静弯时的应力分布特征、最大等效应力及其位置。通过对计算结果进行分析,对钢轨窄间隙电弧焊接头的强度、残余应力等提出了控制要求,可为后续钢轨窄间隙电弧焊接的工艺改进、接头质量控制和性能改善提供有价值的参考。

The static bending test of rail welded joint is an important way to evaluate the welding process and joint quality. Based on the structural features of static bending test system,the contact finite element model including two contact pairs for the static bending test of rail welded joint was established. The influences of parameters of contact pairs,including element size,contact stiffness and so on,on the calculation time and result accuracy were analyzed,and the appropriate element size,contact pair parameters for FE model were determined by optimizing se-lection. Moreover,the applicability of the FE model for stress analysis was confirmed by comparing the calculated results with the experimental results presented in related literature. After that,according to the standard concerning the static bending test of rail joint welded by flash butt welding,the simulating computation of the stress distribution was conducted for both rail head being pressed( forward bending) and rail head in tension( reverse bending) respectively by using the established contact FE model,and the stress distribution characteristics as well as the value and location of the maximum von Mises stress was discovered accordingly. Through analysis on the computational results,the control requirements was put forward on the strength and residual stress of rail joint welded by narrow gap arc welding. These conclusions can offer valuable reference for the subsequent process modification,joint quality control and performance improvement of rail narrow gap arc welding.