Wear and mechanical degradation of ultra-high molecular weight polyethylene (UHMWPE) in hip and total knee replacements are the principal causes of fail of these devices. However, wear tests are expensive and require a long time. Finite element analyses have been an important tool for iterative design purposes.

In this work, a finite element simulation for the indentation test on UHMWPE was performed. UHMWPE was used as substrate with PMMA-SiO₂ and PMMA-CaO as hybrid coatings. First, necessary material properties for the simulation are presented. The UHMWPE substrate was modelled as an elastic-plastic material considering its true stress-strain curves of tension and compression because it was important knowing the mechanical behavior between both formulations. To simulate the indentation, a 65° Berkovich indenter was modelled using diamond's mechanical properties. At once, contact parameters were established between each type of ultra-thin biocompatible coating and the indenter using STANDARD behavior and the Augmented Langrange Algorithm. To obtain the indentation phenomenon, indenter's displacement was controlled and force reaction was monitored.

Oliver-Pharr theory was employed to analyze the finite element solution of the indentation. It helped us to obtain the optimum thickness for both biocompatible coatings. In order to obtain the friction coefficients for both coatings and to validate the results acquired in the simulations, several abrasion test were performed. Our findings showed that the finite element analyses are a very useful tool to calculate the coatings thickness and to predict their mechanical behavior.