Stress Based Model for General Rolling Contact with Surface and Subsurface Survival: Application to Gears with Material Inhomogeneities

Abstract

A previously developed and validated model for the life of rolling/sliding heavily-loaded lubricated contacts, that separates surface and subsurface survival is now adapted to include the effect of material inhomogeneities and it is applied to the case of spur gear contact life. The previously used FFT-based, homogeneous elastic dry contact solver (for the calculation of pressure and subsurface stresses) is now replaced by a previously developed Lamé’s equations solver based on Multigrid methods that can handle bonded inhomogeneities in an elastic media. Despite the increase in computing time by this change it still is able to generate gear solution calculations within one hour computing time in a personal computer. The effect of bonded inhomogeneities in rolling contact fatigue (RCF) is investigated for a variety of inclusion geometries and Young’s modulus values. The results show how deterministically, or randomly distributed inclusions might shorten the RCF life of a component. In engineering practice this can be reflected in a reduction of the fatigue limit used.

Keywords

• rolling/sliding contact life
• gears
• multigrid
• inhomogeneities
• fatigue
• surface life
• sintered materials