基于拓展有限元的齿轮点蚀磨粒形态学特征模拟

Morphological Feature Simulation of Gear Pitting Debris Based on the Extended Finite Element Method

疲劳点蚀是齿轮摩擦副的典型固有磨损特征,其产生的点蚀磨粒已经被用于理解疲劳磨损的发生和发展机理,由于缺乏理论模拟,基于磨粒特征的疲劳磨损机理判断还停留在经验分析层面。为此,拟通过齿轮接触疲劳点蚀的数值模拟,研究点蚀磨粒形态特征,为在线磨粒特征表征磨损状态的方法提供理论探索。在考虑弹流润滑的条件下,建立齿轮副局部接触模型,并采用拓展有限元法(Extended finite element method,XFEM)模拟表面萌生裂纹的拓展过程。进一步分析工况与点蚀磨粒形态特征的关系,结果表明,点蚀磨粒长轴尺寸随初始萌生裂纹的长度增加而增大,随载荷的增加而减小;点蚀磨粒的厚度随初始萌生裂纹的深度增加而增大。通过与已发表的试验结果进行对比,该模型所得到的点蚀形貌尺寸和形状与试验得到的点蚀形貌基本一致,从而验证了该模型的有效性。

Fatigue pitting is one of the inherent features of gear＇s wear mechanism.Accordingly,the morphological feature of pitting debris has been adopted in interpreting the occurrence and development of fatigue failure.However,the accordance of this practice has remained in experiential level due to the lack of theoretical support.Aiming at the on-line monitoring of fatigue pitting failure via particles,a numerical analysis of fatigue pitting process is proposed to extract the morphological features of pitting particles.A simplified local contact model of gears is constructed considering the condition of elasto-hydro dynamic lubrication（EHL）.An extended finite element method（XFEM） is introduced to simulate the propagation of an initial micro-crack.A pitting process is simulated using the proposed method and the influences of boundary conditions on the morphological features of wear particles are analyzed.Results show that the major dimension of the pitting particle depends on both the length of the initial crack and the applied load.And its minor dimension depends on the length of the initial crack.To validate the effectiveness of the proposed model,some reported experimental results are adopted for comparisons.Similar dimensions of the calculated crack and the experimental one reveal the accuracy of the proposed model.