内燃机车底架边梁焊缝疲劳开裂的数值分析与结构优化

Numerical analysis and structural optimization for weld fatigue cracking of side beam of diesel locomotive chassis

针对某型号内燃机车底架结构在运营过程中旁承梁与边梁之间焊缝的疲劳开裂问题,首先基于网格不敏感结构应力方法对原结构进行分析,结果表明,预测的开裂位置和裂纹方向与实际情况一致,证明了所定义的疲劳工况的合理性;然后对所提出的2种结构优化方案进行计算,结果表明,与原结构相比,优化方案II中各局部区域的结构应力至少降低了70%,疲劳寿命提高约36.9倍,满足结构的使用要求,是最优的改进方案。计算结果为结构改进提供了理论依据。

In view of the fatigue cracking problem of the weld between the side bearer beam and the side beam of a certain type of diesel locomotive chassis structure during operation,in this paper,firstly analyzes the original structure based on the grid insensitive structural stress method.The results showed that the predicted crack location and crack direction were consistent with the actual situation,which proved the rationality of the defined fatigue mode.Then,through the calculation of the two proposed structural optimization schemes,the results showed that,compared with the original structure,the structural stress of each local area in the optimization scheme II was reduced by at least 70 percent,and the fatigue life was increased by about 36.9 times,which satisfied the operation requirement of structure.It was the optimal improvement scheme.The calculation results provided a theoretical basis for structural improvement.