空心车轴不同深度表面裂纹应力强度因子研究  

Research on stress intensity factors of surface crack of hollow axles at different depth

作　　者：周素霞[1] 张俊清[2] 谢基龙[2] 

机构地区：[1]北京建筑工程学院机电与汽车工程学院,北京100044 [2]北京交通大学轨道车辆结构可靠性与运用检测技术教育部工程研究中心,北京100044

出　　处：《计算力学学报》2010年第4期704-710,共7页Chinese Journal of Computational Mechanics

基　　金：国家重点基础研究发展计划973(2007CB714705)资助项目

摘　　要：分析了空心车轴的旋转弯曲载荷的特点,建立了空心轴表面周向半椭圆裂纹的模型,给出了半椭圆裂纹的构形参数定义,即形状比、深度比和裂纹前缘相对位置。采用四分之一20节点等参退化奇异单元,通过有限元计算,模拟裂纹前沿的应力奇异性。在此基础上,计算了裂纹前缘表面点和中心点的应力强度因子随着裂纹扩展深度和旋转角度的变化。计算结果表明,对于给定的裂纹构形,在车轴的一个载荷循环中,裂纹前缘同一相对位置的应力强度因子是不断变化的,不同位置的应力强度因子在达到最大值的角度也是不同的,这就导致了裂纹前缘表面点在一些角度下的扩展是不对称的。这些结果为进一步研究空心轴表面裂纹的扩展路径和寿命提供了参考。Stress intensity factors（SIFs） of circumferential semi-ellipse crack at the external surface of hollow axles subjected to rotary bending loading are researched using a 3D finite element model.The 3D finite element analysis is carried out by employing quarter-point 20-node isoparametric degenerate singular elements to obtain the stress intensity factors along the crack front.The semi-ellipse crack configuration are defined with two parameters： the aspect ratio a/b（a,b=ellipse semi-axes）,the relative depth a/t（t,the thickness of the hollow axle＇s wall）.An analysis about the influence of the rotary angles and crack depth on SIFs is presented at the surface and the center points of the crack front.It is shown that the stress intensity factors at the same relative position along the crack front change significantly under a loading cycle for a given crack.Moreover,the maximum values of the stress intensity factors at different locations appear at different rotary angles.So the crack propagation at the surface points are asymmetry.The results will help to research propagation path and life of the surface crack of hollow axles.

关 键 词：空心车轴 表面裂纹 应力强度因子 有限元 

分 类 号：O242.21[理学—计算数学] U270.33[理学—数学]