基于体积法的缺口件多轴疲劳寿命预测  

Fatigue life prediction for notched specimen based on the volume approach under multiaxial loading

作　　者：谭晶莹[1] 李江华[2] 孙然[2] 金丹[2] 

机构地区：[1]湖南理工学院机械工程学院,岳阳414006 [2]沈阳化工大学能源与动力工程学院,沈阳110142

出　　处：《应用力学学报》2016年第4期726-730,746,共5页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(11102119);国家重点基础研究发展计划(2011CB706504);湖南省自然科学基金(13JJ6067)

摘　　要：针对Mod.9Cr-1Mo钢不同缺口半径下的多轴疲劳试验结果进行模拟计算,采用体积法进行疲劳寿命预测,并与等效应变法的预测结果进行了对比。模拟结果表明,各路径下缺口根部应力集中程度随缺口半径减小而更为明显,最大应力集中程度达3.45。等效应变法给出的疲劳寿命预测结果随着缺口半径的减小而偏于保守,保守量高达90倍。为克服等效应变法给出的偏于保守的结果,基于剪应力随距缺口根部距离的变化趋势进行有效距离的计算,采用体积法进行寿命预测,94.1%的预测结果位于2倍分散带内。The notched specimens with different notched radius for Mod.9Cr-1Mo steel under multiaxial loading are simulated. The fatigue lives are predicted by equivalent strain approach and volumetric approach. Simulation results show that the stress concentration at the notched root is observed for all the strain paths and it is significant for the smaller notched radius. The maximum stress concentration factor is 3.45. The predictions for equivalent strain approach are more conservative with decrease in notched radius, which of the conservative predictions can reach up to 90 times. The effective distance is calculated based on the variation trend of the shear stress with the distance of the notched root. The fatigue lives for all strain paths are predicted by the volumetric approach. On the whole, 94.1% prediction results are within a factor-2 scatter band.

关 键 词：缺口件 相对应力梯度 体积法 疲劳寿命预测 

分 类 号：O346[理学—固体力学]