焊接油底壳开裂问题研究及优化设计

Study on Welded Sump Cracking and Design Optimization

在发动机耐久试验过程中,某大型柴油机油底壳挡板焊缝处发生开裂,造成油底壳漏油故障。采用瞬态动力学仿真计算、振动测试等方法对油底壳进行分析研究。研究结果表明,焊缝的应力幅超出许用限值、焊接处振动大是造成油底壳开裂的主要原因。通过改变油底壳外形结构、增加加强筋的方式来提高油底壳侧壁刚度,以降低油底壳挡板焊缝处的应力幅和焊接位置的振动水平。改进后的油底壳通过验证试验,未发生开裂故障,说明改进措施有效。

The oil sump of a larger diesel engine cracked at the welded joint between the shell and baffle plate during the engine durability test,causing oil leak.Transient dynamics simulation and vibration testing were utilized to study the cracking.The results showed that the vibration at the welded joint was serious and stress amplitude exceeded the limit.To reduce the stress amplitude and vibration at the welded joint,modifying the shape structure of the oil sump and increasing the quantity of reinforcing rib were adopted to enhance the oil sump wall stiffness.The improved oil sump was verified by durability test and no cracking occurred.This demonstrates the improving measure is effective.