Analysis of the Completely Closed Subsurface Crack Using the Matrix of Two Dimensional Weight Function

Elliptical subsurface cracks, under rolling contact fatigue, are special due to the coupling of the fracture modes and the crack closure. In this paper, the ability of the matrix of two dimensional weight function, to analyze the completely closed subsurface crack is investigated. Weight function method has a super position base and so, the ability is evaluated for the frictionless contact between crack surfaces. To do this, mixed mode stress intensity factors of a subsurface crack front under semi-ellipsoid of contact pressure are calculated using the matrix of two dimensional weight function and subsurface stress field. The results are compared to finite element stress intensity factors with high accuracy. It is concluded that the matrix of weight function is able to quick analyze the completely closed subsurface crack with high accuracy if the compression normal stress is vanished. Also, the effects of the aspect ratio and depth of the crack on the stress intensity factors are investigated.