A NUMERICAL-SOLUTION OF A SURFACE CRACK UNDER CYCLIC HYDRAULIC PRESSURE LOADING

Material degradation and failure in rolling contact components are oft en associated with surface crack initiation and propagation under repe ated contact loading. In the presence of lubricating fluid, the hydrau lic pressure in the fluid Jilin between the contacting surfaces may pl ay an important role in the crack growth process. This paper presents a method to model the effect of hydraulic pressure loading on surface Department of Theoretical I crack growth. The governing equations of t he coupled viscous fluid/cracked solid and Applied Mechanics, problem are obtained, which are nonlinear integral and differential equations. The fluid is assumed to be Newtonian and incompressible. The cracked solid is considered to be linearly elastic. Pressure loading history i s prescribed at the crack mouth. Finite difference methods are used to solve the governing equations. For each time step, Newton-Raphson ite ration method is used to search for the root of the nonlinear equation s. Both transient and steady-state pressure distributions under cyclic pressure loading are obtained using this method. A few numerical exam ples are given to demonstrate the reliability and effectiveness of the solution method. The solution shows that there exists a characteristi c time, which determines whether pressure fluctuations at the crack mo uth can be transmitted deep into the crack. The steady-state pressure distribution exhibits a phase delay from the applied cyclic loading.