油膜润滑的发动机曲轴疲劳寿命分析

在Virtual lab中建立某型V8发动机曲轴系统的多体动力学模型,考虑曲轴系统的油膜润滑条件,创建主轴颈处润滑的油膜文件,通过多体动力学仿真计算,得到曲轴在弹性支撑下的载荷历程,并将其作为疲劳寿命分析的输入参数;利用Virtual.Lab的Durability模块对曲轴进行疲劳寿命计算,获得精确的曲轴损伤分布和疲劳寿命。仿真结果表明:通过系统多体动力学仿真能够得到部件准确的载荷情况,考虑油膜润滑真实的反映了曲轴受载情况;曲轴寿命最短处为第一曲拐与第二主轴颈过渡处内侧。

Fatigue Analysis of Crankshaft Based on Oil Film Lubrication

In order to predict the fatigue life of a crankshaft accurately,the fatigue analysis of the crankshaft based on rigid-flexible coupling dynamics simulation was discussed.A multi-body dynamics model of the crankshaft system was established in LMS.The dynamics model consists of the crankshaft,the piston,the connecting rod and the flywheel.The modal participation factors were obtained by rigid-flexible coupling dynamics simulation.As an input condition of fatigue analysis,the load time history was gained by the linear superposition of the modal participate factors and the modals.The accurate fatigue life and damage distribution of the crankshaft were obtained by fatigue analysis on the durability module of LMS.Virtual.Lab.The results show that the fatigue analysis with the load time history obtained by rigid-flexible coupling dynamics simulation can ensure the match of the modal participation factors and the finite element model.The maximum stress and the shortest fatigue life of the crankshaft were located in the joints of the crank and the second crankshaft journal.