Boundary element analysis in contact fracture mechanics

This thesis is concerned with the analysis of two-dimensional (2-D) and three-dimensional (3-D) elastic contact problems involving cracks using the boundary element method (BEM). The quadratic isoparametric formulation is used throughout, and for treating crack problems, the near-tip fields for both open and closed crack tips are properly modelled using special crack tip elements. These elements also provide a quick and direct means of obtaining the stress intensity factors. The classical contact algorithm using a load incremental-iterative approach is employed to treat frictional contact problems.;The BEM for 2-D contact mechanics is first applied to a number of angled crack problems involving crack surfaces in contact. Stress intensity factor solutions are presented for a range of geometries and coefficients of friction in each of the problems treated. The problem of a pin-loaded, straight attachment lug with a single edge crack at the pin hole, with or without a bushing, is then analysed. Stress intensity factor solutions are obtained for several cracked lug geometries under a wide range of frictional contact conditions between the pin and the lug. Finally, the BEM for 3-D frictional contact mechanics analysis is used to analyse four crack problems. Three of these problems involve crack closure under bending loads, and the fourth is that of a pin-loaded rectangular plate with corner cracks at the pin-hole.;Where possible, the BEM results are compared with those available in the literature and good agreement between them is obtained. The present study shows that friction between the crack surfaces in contact can have a significant effect indeed on the magnitude of the stress intensity factors for all the problems considered. It also shows the importance of carrying out a proper contact mechanics analysis for a number of crack problems.