• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.2
• /
• pp.221-228
• /
• 1989

The objective of this paper is to develop a numerical technique for analyzing crack driving forces in multi-phase materials. The analysis was based on finite element method coupled with a virtual crack extension technique which is known as the most efficient tool in computational fracture mechanics analysis. The modified J-integral method, proposed by Miyamoto and Kikuchi for the analysis of dual-phase material was carried out by subtracting the J-values for contours surrounding each phase boundary from the J-values for overall contour. It was shown that the proposed numerical procedure, based on the modified J-integral coupled with a virtual crack extension technique, can be used as an effective numerical tool for determining crack driving forces in multi-phase materials.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.3
• /
• pp.80-88
• /
• 2010

A simple computational model for modeling of subsurface crack growth under cyclic contact loading is presented. In this model, it is assumed that the initial fatigue crack will initiate in the region of the maximum equivalent stress at certain depth under the contacting surface. The position and magnitude of the maximum equivalent stress are determined by using the equivalent contact model, which is based on the Hertzian contact conditions with frictional forces. The virtual crack extension method is used for simulation of the fatigue crack growth from the initial crack up to the formation of the surface pit due to contact fatigue. The relationships between the stress intensity factor and crack length are then determined for various combinations of equivalent contact radii and loadings.