基于临界曲面的改进Paris定律球轴承疲劳寿命预测方法  

Fatigue Life Prediction of Ball Bearings by Modified Paris Law Based on Critical Curved Surface

作　　者：徐东[1] 徐永成[1] 陈循[1] 李兴林[2] 杨拥民[1] 

机构地区：[1]国防科技大学机电工程与自动化学院,长沙410073 [2]杭州轴承试验研究中心有限公司,杭州310022

出　　处：《机械工程学报》2011年第2期51-57,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50705096);高档数控机床与基础制造装备科技重大专项(2009zx04014-014)资助项目

摘　　要：通过场发射扫描电镜对球轴承疲劳故障点微观结构进行观察,发现裂纹总是沿着某个曲面进行萌生和扩展,扩展到一定程度后发生断裂形成近似椭圆形状的剥落点,随着球轴承的运转,不仅断裂后的裂纹发生二次剥落,而且剥落点将在新的曲面上发生多次剥落,形成断层形貌。基于此种现象,提出球轴承临界曲面的概念,假定裂纹的萌生和扩展均在此临界曲面上,将三维裂纹扩展问题转化为二维裂纹扩展问题进行分析。在临界曲面概念的基础上,提出改进的Paris疲劳寿命预测模型,将疲劳寿命分为裂纹扩展和剥落点增大两部分,分段采用改进的Paris定律预测球轴承的疲劳寿命。通过多套SKF 6205深沟球轴承疲劳寿命试验数据进行验证,与传统的SKF L-P公式预测结果相比,提出的方法能够较好地预测球轴承的疲劳寿命。Microstructures of flaws of ball bearings are investigated by using field emission scanning electron microscope and it is found that both crack initiation and crack propagation are always along a certain curved surface.Propagating to a certain degree,the crack will fracture and form an elliptic flaw.Along with the ball bearing operating,not only the flaw continues to flake away,but also some new cracks initiate and propagate along new curved surfaces and fracture ultimately.There are many cross sections in the flaw.Based on this phenomenon,the critical curved surface of ball bearing is proposed and crack initiation and propagation are assumed to be on this critical curved surface.In virtue of this method,three dimension problems are converted to two dimension ones.Based on this,a modified Paris fatigue life prediction model is proposed.The fatigue life is divided into two sections：crack propagation and flaw size gain,and fatigue life are predicted by sectional Paris law.The model is validated by fatigue test life data of SKF 6205 deep groove ball bearings.In comparison with the prediction of traditional SKF L-P formulary,the proposed model produces more accurate results.

关 键 词：临界曲面 PARIS 定律 疲劳寿命预测 预测模型 球轴承 

分 类 号：TH133.33[机械工程—机械制造及自动化] TG115.5[金属学及工艺—物理冶金]