基于多体动力学的柴油机曲轴疲劳强度与寿命分析

Analysis of fatigue strength and life of diesel crankshaft based on multi-body dynamics

结合多体动力学和有限元分析方法对某预研柴油机曲轴进行了疲劳强度分析,得到了曲轴动态应力分布;利用常规的校验结构强度安全性的方法,计算了曲轴在交变载荷下的安全系数和疲劳寿命。结果表明:原设计结构中曲轴疲劳安全系数与寿命略显不足。根据该柴油机预研目标,提出了曲轴结构改进措施。改进后的曲轴应力分布、疲劳安全系数、疲劳寿命都符合要求。

The rigid-flexible multi-body system dynamics and finite element method were applied to make the analysis of the fatigue strength of the crankshaft of a diesel under study, and thus its dyna- mic stress distribution was obtained. Based on the general analysis results, the safety factors and fa- tigue life of the crankshaft were further calculated. The results show that there are deficiencies in the original design of crankshaft about the stress distribution, safety factors and fatigue life. According to the object of advance research on the diesel engine, measures were proposed to improve the structure of crankshaft to meet the needs of stress distribution, safety factors and fatigue life.