基于裂纹萌生和扩展的渗氮钢疲劳寿命预测  

Prediction of fatigue life of nitrided steel based on crack initiation and propagation

作　　者：孙振铎 侯东勃 李伟[2] 董鹏 SUN Zhenduo;HOU Dongbo;LI Wei;DONG Peng(School of Quality and Technical Supervision,Hebei University,Baoding 071000,China;School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China;Hebei Technology Innovation Center for Lightweight of New Energy Vehicle Power System(Under planning),Hebei University,Baoding 071000,China)

机构地区：[1]河北大学质量技术监督学院,河北保定071000 [2]北京理工大学机械与车辆学院,北京100081 [3]河北大学河北省新能源汽车动力系统轻量化技术创新中心(筹),河北保定071000

出　　处：《兵器材料科学与工程》2021年第5期76-82,共7页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(51775043);河北省自然科学基金(E2018201265);河北省高等学校科学技术研究项目(QN2017307)。

摘　　要：以渗氮CrNiW钢的光滑试样和两种缺口试样为研究对象,开展超高周疲劳试验。观察渗氮CrNiW钢的疲劳断口显微组织,分析S-N曲线特性及失效机理,基于裂纹萌生模型和裂纹扩展模型计算渗氮CrNiW钢的萌生和扩展寿命,结合裂纹萌生和扩展寿命计算总疲劳寿命。结果表明:随应力集中系数增加,ΔK_(FGA)小幅降低,ΔK_(fish-eye)减小明显;应力幅值较低时,裂纹萌生寿命占总疲劳寿命的比例很高,裂纹扩展寿命占比很低,基本可忽略;模型预测的总疲劳寿命与试验结果较接近,除个别数据点外,预测结果均在2倍偏差内,预测较准确。A smooth specimen and two notched specimens of nitride CrNiW steel were selected as experiment object,and very high cycle fatigue tests were carried out. The microstructures of fatigue fracture of nitrided CrNiW steel were observed. The S-N characteristics and failure mechanism were analyzed. The fatigue crack initiation life and propagation life were calculated by crack initiation life prediction model and propagation life prediction model separately,and the total fatigue life was calculated in combination with the crack initiation life and propagation life. The results show that the value of ΔK_(FGA) decreases slightly and the value of ΔK_(fish-eye) decreases significantly with the increase of stress concentration factor. Under lower fatigue stress amplitude,the crack initiation life accounts for a high proportion of the total fatigue life,whereas the crack propagation life accounts for a very low proportion,which can be ignored. The total fatigue lives predicted by the model are close to the test results,the predicted results are within 2 times of the deviation except for individual data points,and the predicted results are more accurate.

关 键 词：渗氮CrNiW钢 超高周疲劳 裂纹萌生 裂纹扩展 疲劳寿命 

分 类 号：TB114.3[理学—概率论与数理统计] O346.2[理学—数学]