弯曲载荷下曲轴疲劳裂纹扩展数值模拟与分析  

Numerical Simulation and Analysis of Crankshaft Fatigue Crack Propagation under the Action of Bending Load

作　　者：常志刚[1] Chang Zhigang(AVIC China Aero-Polytechnology Establishment,Beijing 100028,China)

机构地区：[1]中国航空综合技术研究所,北京100028

出　　处：《工程与试验》2018年第3期17-21,88,共6页Engineering and Test

摘　　要：裂纹扩展规律是研究疲劳裂纹扩展寿命的重要内容。本文以具有复杂结构特征的内燃机曲轴为例,以曲轴实际的弯曲疲劳断口分析为基础,测量裂纹萌生区的几何特征作为曲轴裂纹体的仿真建模输入,采用有限元数值模拟计算萌生区裂纹前缘的应力强度因子,分析了由萌生至断裂过程中裂纹前缘形状比的变化规律。基于X射线应力法测量了曲轴裂纹区的残余应力分布状态,讨论了表面强化层对裂纹扩展的影响,最后给出了考虑表面处理的曲轴弯曲疲劳裂纹的扩展规律。Crack propagation law is an important content to study the fatigue crack growth life. Taking the crankshafts of internal combustion engine with complex structural features as an example, based on the actual bending fatigue fracture analysis of crankshafts, the geometrical characteristics of the crack initiation zone are measured and used as the input of simulation modeling of cracked crankshafts. The finite element method is used to calculate the stress intensity factor of crack front in crack initiation zone, and the change trend of shape ratio of crack front during the crack propagation is analyzed. Based on X-my stress method, the residual stress distribution in crankshaft crack region is measured, and the effect of surface strengthening layer on crack propagation is discussed. Finally, the general rule of crankshaft crack propagation under bending fatigue load is given.

关 键 词：曲轴 弯曲疲劳 裂纹扩展 应力强度因子 

分 类 号：TG111.91[金属学及工艺—物理冶金]