Elasto-plastic finite element analyses of three-dimensional and two-dimensional repeated rolling contact

The purpose of this dissertation has been to further our understanding of the phenomenon of rolling contact, using the finite element method.;An elasto-plastic finite element model has been developed to study repeated, frictionless, three-dimensional rolling contact. This model has been used to perform calculations for different contact conditions, geometries and materials. The complex loading associated with 3-D contact has been described--the translating stress tensor superimposed on a static or residual stress tensor. Cyclic plasticity in the vicinity of the rolling track has been characterized by means of: (1) distributions of residual stresses and strains, equivalent plastic strains and plastic strain increments, (2) residual distortions and (3) stress-strain hysterisis loops. The important aspects of repeated 3-D contact (as compared to 2-D plane strain contact) have been discussed: (1) 3-D contact is more constrained, (2) in-plane, as well as, out-of-plane deformation is possible, (3) all six components of the stress and strain tensor are possible in the residual state. This study demonstrates the necessity of selecting appropriate stress-strain behaviour for different materials and loading conditions.;Two sets of thermo-mechanical finite element calculations have been performed to include the heating that accompanies repeated rolling-plus-sliding contact. This work represents preliminary efforts towards developing a sophisticated elasto-plastic finite element model to realistically simulate repeated translating thermo-mechanical contact. Both analyses are two dimensional. The first one is stationary and the second one is translating. Appropriate boundary conditions have been derived to simulate a semi-infinite body. In addition to the stresses, strains and displacements, temperature distributions have been presented. In spite of numerous simplifications and assumptions, useful insights have been obtained. Of importance are the relative magnitudes of the thermal and mechanical loads. Tensile stress components, (1) residual and (2) ahead and behind the transient thermo-mechanical loads, have been described. The origin of the residual tension appears to be the compressive thermal stresses due to the temperature gradients followed by the nonuniform thermal contraction. Temperature dependence of the thermo-physical and mechanical properties has been discussed.