Prediction of Wear of Acetabulum Inserts Due to Multiple Human Routine Activities

Abstract

It is difficult to predict the quantitative and qualitative aspects of the wear of the components that allow relative motion due to several factors. First, the prosthetic parts in contact experience a wide spectrum of loadings induced by the large domain of common activities. Secondary, the contact conditions evolve due to wearing, a long-time prediction implying a high level of nonlinearity. The authors tried to overcome all these difficulties using a complex predictive model that combines statistical evaluation, nonlinear mechanical analyses of load transfer by the contact interface and tribological estimations of the wear characteristics. After a theoretical description of the predictive model, one could notice an application for an artificial hip joint – a frictional titanium alloy on UHMWPE couple. Several loading regimes are considered as characterised in [1]. For every regime a dynamic Finite Element simulation of the dry-friction contact was performed establishing the contact traces and the contact pressure distribution. Those characteristics combined with the frequencies of the activities considered (as determined in [2]) are input data for a statistical evaluation of the joint loading during some period. Developing an original method the authors could evaluate the volume of wear debris across different activities based on the joint load transfer characteristics specific to each activity.