INVESTIGATION OF CRACK-PROPAGATION DURING CONTACT BY A FINITE-ELEMENT METHOD

This paper presents a numerical method, based on the finite element approach, for the analysis of stress states in cracks during contact. The problem is considered to be two-dimensional, but the method also allows three-dimensional cases to be solved. The investigations concern the contact between a steel roller and a rectangular steel block with cracks of known geometry, i.e. surface-breaking cracks perpendicular to the contact surface and oblique to it, and cracks parallel to the surface located at various depths. Different configurations of load relative to the crack are considered which correspond to quasi-static rolling of the roller over the surface of the block. Normal and tangential loads are applied. As results, the changes in crack shape during rolling are presented. Diagrams of the tangential forces during contact in the following stages of rolling are shown. Finally, stress-intensity factors K(I) and K(II) are calculated and presented on plots vs. the position of the load axis relative to the crack. In conclusion, existing hypotheses concerning crack propagation during contact are confirmed, and new hypotheses are presented.