摘要
以某柴油机连杆为对象,系统地开展了疲劳强度、寿命的试验和数值预测研究工作。借助有限元分析技术,确定了连杆薄弱位置和疲劳试验方案,通过模拟连杆静态加载的电测试验验证了连杆部件疲劳试验系统的线性响应特性。疲劳试验结果显示,该连杆疲劳失效形式具有明显的规律性,裂纹位置出现在靠近小头杆身部位处和杆身某标志字处,通过残余应力测试发现标志字处的失效与残余应力大小密切相关。最后,建立了连杆疲劳寿命理论预测模型,将残余应力作平均应力处理,基于Haigh图考虑平均应力对S-N曲线的影响,预测了在不同载荷系数和残余应力作用下连杆标志字处的疲劳寿命和安全系数。该模型预测结果与试验值基本相符,可用于后续连杆疲劳寿命预测工作。
The fatigue strength and life test and their numerical prediction of an engine connecting rod were researched system- atically. The weak position of connecting rod and the fatigue test scheme were determined based on the finite element analysis technology. By the electrical measurement test of simulated static loading, the linear response characteristics of connecting rod component fatigue test system were verified. The fatigue test results show that the fatigue failure mode of connecting rod has prominent regularity. The crack appears near the small end of connecting rod and the mark of rod. The further test shows that the crack near the mark is closely related to the residual stress. Finally, the prediction model of fatigue life was built. Consider- ing the influence of mean stress from the residual stress on S-N curve based on Haigh diagram, the fatigue life and safety factor in the mark position of connecting rod are predicted under different load factors and residual stresses. The predicted result coin- cides with the test and can be used in the future fatigue prediction of connecting rod.
出处
《车用发动机》
北大核心
2013年第4期41-45,共5页
Vehicle Engine
关键词
连杆
有限元分析
疲劳试验
残余应力
疲劳寿命
connecting rod
finite element analysis
fatigue test
residual stress
fatigue life
