柴油机曲轴的疲劳寿命分析

Analysis of Fatigue Life-span of Diesel Engine Crankshaft

曲轴是柴油机的重要组成部件,直接决定发动机的使用寿命.在工作状态下,曲轴受到旋转质量离心力、气体压力和往复惯性力的共同作用.利用软件来模拟曲轴的实际工作情况,并对曲轴进行疲劳寿命分析具有重要的现实意义.首先,在UG中生成曲轴的三维模型,利用Hypermesh划分网格,将有限元模型导入ANSYS中进行静力学分析,得到曲轴工作状态下的最大应力值和位移值,同时输出用于动力学仿真分析的曲轴柔性体.然后,在ADAMS中进行曲轴的刚柔耦合动力学分析,输出曲轴运动过程中的载荷谱.最后,在疲劳分析软件n Code中计算出曲轴的疲劳寿命,为后续的优化设计提供参考.

Crankshaft is the most important component of diesel.Its performance directly influences the life-span of diesel.The force in the working process of crankshaft is complex,by centrifugal force of rotating mass,gas inertial force and reciprocating inertial force of cycle change work together.It is very important to analyze the dynamic characteristics and strength,and evaluate the fatigue life-span of the crankshaft.First,using three-dimensional modeling software UG established the three-dimensional solid model of crankshaft,using Hypermesh meshed of crankshaft and got the finite element model of the crankshaft.The finite element model of crankshaft was imported into ANSYS to do static analysis and free modal analysis in order to obtain the deformation value and the stress value under the condition of the maximum load.Meanwhile,the flexible body file of crankshaft was outputted.Then,utilizing dynamic simulation software ADAMS carried out rigid-flexible coupling dynamics simulation of crankshaft in order to get the load spectrum file of crankshaft movement.Finally,used n Code fatigue analysis software to establish the fatigue analysis model of crankshaft,got the fatigue life-span of crankshaft,and provided reference for the subsequent optimization design.