接触载荷作用下的表面裂纹分析

Analysis of Surface Crack Subjected to Contact Loadings

用边界积分方法分析了表面裂纹在接触载荷作用下的张开位移和应力强度因子.该方法将埋在无穷大弹性介质中裂纹模拟为连续分布的位错环,根据两个位错环之间的相互作用能可以得到弹性体的应变能,对弹性体的势能取极值,可以得到关于裂纹张开位移的边界积分方程.通过把半空间的边界模拟成一个包含在无穷大弹性介质中大裂纹,该方法能用已有的边界积分方法很好的处理具有任意表面形状的表面裂纹.文中算例分析了不同倾角的表面裂纹在法向和切向接触载荷作用下,裂纹尖端的应力强度因子.其结果对于分析路面表面裂纹的扩展具有重要意义.

The stress intensity factors and opening displacements of the surface crack subjected to contact loadings are analyzed by means of a variational boundary integral method (VBIM). This method represents the crack as a continuous distribution of dislocation loops. The crack opening displacements can be determined by minimizing the elastic potential energy, obtained from the known expressions of the interaction energy of a pair of dislocation loops, of the solid. By modeling the surface of the halfspace as a large crack breaking through an infinite solid, this paper demonstrates that the VBIM can be well extended to analyze the surface crack of arbitrary geometry. The stress intensity factors of surface crack with various inclined angle subjected to normal and shear contact loadings are obtained. The numerical results can help to determine the direction of crack growth.