基于改进Paris-Erdogan方程的粉末冶金零件在循环应力下的服役寿命预测  

Service life prediction of powder metallurgy parts under cyclic stress based on improved Paris-Erdogan equation

作　　者：何喆 宋晓阳 高春雷 何国华 张钰荧 HE Zhe;SONG Xiaoyang;GAO Chunlei;HE Guohua;ZHANG Yuying(Railway Engineering Research Institute(National Engineering Laboratories for System Test of High-speed Railway),China Academy of Railway Sciences,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司铁道建筑研究所(高速铁路轨道系统全国重点实验室),北京100081

出　　处：《扬州大学学报（自然科学版）》2024年第6期9-16,共8页Journal of Yangzhou University：Natural Science Edition

基　　金：中国铁道科学研究院集团有限公司院基金课题(2023YJ206);中国国家铁路集团有限公司课题(K2021G015).

摘　　要：以粉末冶金工艺制成的镍基高温合金拨叉为研究对象,通过改进Paris-Erdogan方程提高脉动循环应力条件下拨叉服役寿命的计算精度。鉴于高应力循环次数下裂纹加速扩展的特点,在Paris-Erdogan方程的材料指数项中引入应力循环次数,补偿裂纹加速扩展阶段出现的偏差,实现拨叉服役寿命的准确预测。为检验服役寿命的计算精度,在拨叉薄弱部位预制2、5和8 mm等3种长度的缺口,设计脉动循环应力加载试验测量拨叉服役寿命,并将试验结果与计算结果进行对比。结果表明,裂纹扩展方向与加载方向垂直,3种预制缺口拨叉的服役寿命分别为37.2、19.4和6.9万次应力循环,改进模型的服役寿命计算误差在6.2%以内,计算准确性提高约40%。The calculation accuracy of the service life of nickel-based superalloy fork manufactured by powder metallurgy is improved by modifying the Paris-Erdogan equation.In view of the characteristics of crack acceleration under high stress cycles,the number of stress cycles is introduced into the material exponent of Paris-Erdogan equation to compensate for the deviations at crack acceleration and propagation stage,and to accurately predict the service life of the fork.To verify the calculation accuracy of service life,three types of notches with lengths of 2,5,and 8 mm are prefabricated at the vulnerable locations of the forks.A pulsatingcyclicstress loading test is carried to measure the service life of the fork,and the test results are compared with the calculated results.The results show that the crack propagation direction is perpendicular to the loading direction,and the service life of the three kinds of prefabricated notch fork is 372000,194000,and 69000 stresscycles,respectively.The service life calculation error of the improved model is less than 6.2%,and the calculation accuracy is improved by about 40%.

关 键 词：断裂力学 裂纹扩展 Griffith方程 Paris-Erdogan方程 寿命预测 

分 类 号：TH142.2[一般工业技术—材料科学与工程]