SIMULATION OF HERTZ CONTACT BETWEEN TWO HIGHLY CONFORMAL, DEFORMABLE, AXISYMMETRIC SOLIDS
This project is aimed at studying the effect of case hardening on the performance of bearings steels in Rolling Contact Fatigue phenomenon. It has multiple objectives. First one of them is to accurately determine surface and subsurface stress fields for the contact between two highly conforming Axi-symmetric solids. Abaqus software was used to solve this challenging contact mechanics problem using finite element method. Theoretically, Hertz calculations predict nonlinear pressure- over closure relationship for the contact between two conforming solids. Specifically, the contact stiffness continuously decreases with increasing over closure between the two surfaces. This was successfully modeled in Abaqus using advanced contact controls. User defined pressure – over closure relationship was used to solve for the soft contact between two bodies. And penetration between Master and Slave surfaces was minimized using Symmetric Contact Pairs approach coupled with refined mesh on both surfaces. Analysis shows that error between theory and FEA results are about 1 %. Therefore, highly conformal contact between two deformable axisymmetric solids was successfully modeled using Abaqus software. Case hardening of steels results in inhomogeneous material near the surface region. Hence, this model is being used to study the effect of inhomogeneous material on the localized stress fields near the contact area. Using Lundberg and Palmgren theory, altercations in stress fields will be quantified as percent (%) improvement in the rolling contact fatigue life (i.e. L10 life) of the bearing components.