FINITE ELEMENT ANALYSIS OF SLIDING CONTACT BETWEEN A CIRCULAR ASPERITY AND AN ELASTIC URFACE IN PLANE STRAIN CONDITION

Wear is a critical phenomenon affecting service life of products. Therefore, wear prediction is an important concern of study. In this study, sliding contact was modeled using LS-DYNA. FEMB was used to create the geometry of the model and the input file was manually modified as necessary. Studies were done to test, calibrate, and validate the model in LS-DYNA before simulation of the sliding wear by an asperity sliding over a plastically deforming and work hardening material surface. A flat half-space with dimensions of 30μm depth and 100μm width is subjected to sliding contact by a semicircular asperity of radius 10μm. The third dimension of the model was assumed to be infinite and therefore a plane strain condition was studied. Elastic indentations were performed to validate the finite element model. Elastic indentation results were compared to the predictions of the Hertz theory of elastic contact. With the help of mesh convergence study the best conditions to simulate sliding wear were determined. Mesh dimensions, hourglass control, contact algorithm, application of the normal load, and mass scaling were the main issues of the study. According to the Hertz theory, the maximum contact pressure and the maximum shear stress were calculated as 2684 and 805 MPa for the conditions studied. Numerical models predicted 10-15% higher values higher values for those stresses. However, normalized stress values show a very good agreement with the theoretical predictions.