Thermomechanical Effects due to Hot Rolling Contact on the Energy Release Rates of Multiple Interface Cracks in Layered Media.

Abstract

This paper deals with the mutual interference of multiple two-dimensional interface cracks in a surface coating layered material under thermal stresses due to rolling/sliding contact with heat input. Contact loading is simulated as a contact pressure load with both the normal and shear components having parabolic distribution. Attention here is focused on the energy release rate at the crack tips which provide a measure for quantifying the magnitude of interface crack growth. In the present crack analysis, the interface cracks are replaced by the distributed edge dislocations, and the crack face friction is negrected. The problem is reduced to simultaneous singular integral equations for dislocation densities. The integral equations can be solved numerically by considering the nature of the singularities at the crack tips. The numerical results of the energy release rate showing the effects of the mutual interference of a pair of interface cracks are given for some tribological material coatings on a steel substrate. The effects of the frictional coefficient, the heat input strength and the coating thickness upon the magnitude of the energy release rate and it's mutual interference are considered numerically.