Numerical simulation of growth pattern of a fluid-filled subsurface crack under moving hertzian loading

Abstract

Cracking of a fluid-filled subsurface crack is studied by means of the distributed dislocation technique within the framework of twodimensional linear elastic fracture mechanics. The Griffith crack was initially opened by the application of hydrostatic pressure of an incompressible fluid within the crack. A moving Hertz line contact load distribution is applied at the surface of the half-plane in the presence of friction. The stress intensity factors at the tips of the fluid-filled crack are analyzed with the restriction that due to the fluid incompressibility there is no change of the crack-opening volume. When the crack starts to propagate/kink, numerical results show that the internal fluid pressure will be relieved, and as the ratio of the branched crack length to main crack length increases, the elastic strain energy release rate decreases. The crack growth is assumed to be arrested when the energy release rate is below a certain value. Based on the energy criterion, predictions are attempted for determining the load position where the crack propagation/kink commences as well as the growth increment of the branch crack before it is arrested. A step-by-step crack path is constructed to simulate the growth pattern of the fluid-filled crack under moving Hertzian loading.

An application of the weight function technique to inclined surface cracks under rolling contact fatigue, assessment and parametric analysis

“…In Bower's paper [11], which dealt with pressurization and entrapment phenomena, the crack SIFs were obtained by the dislocation distribution method, previously proposed by Keer and Bryant [12]. The dislocation distribution technique was also applied by Johnson [13] and, more recently, by Jin et al [14]. Murakami et al [15] used a Finite Element (FE) 3D model that reproduces the typical arrow head shape of the crack.…”

Two basic approaches in a search of the crack propagation angle

“…Moreover, steep crack propagation to the free surface in rolling–sliding contact fatigue can be caused by the lubricant hydraulic pressure on crack surfaces. To describe the rolling–sliding contact fatigue phenomenon, models and criteria of fracture mechanics can be very attractive …”

“…To describe the rolling-sliding contact fatigue phenomenon, models and criteria of fracture mechanics can be very attractive. 34,35 It is well known that if plastic zone in the vicinity of the crack tip is small in comparison with crack sizes, linear-elastic fracture mechanics can be successfully used. Several fracture criteria have been developed to analyse failure phenomena in the vicinity of the surface crack tip under rolling-sliding loading.…”

Surface and subsurface rolling contact fatigue characteristic depths and proposal of stress indexes

“…Way [43] was the first who obtained an experimental evidence of fluid pressurization enhanced pitting. After this initial experimental work, the pressurization mechanism was investigated (both experimentally and numerically) in many other papers [34,37,42,[44][45][46][47].…”