Modelling the Effects of Head Diameter and Cup Wall Thickness on Contact Mechanics and Wear of Cross-Linked UHMWPE Cups
A three-dimensional contact-coupled wear model was developed and used to predict the long-term wear in both conventional and cross-linked ultra high molecular weight polyethylene (UHMWPE) cups, particular to examine the effect of the head diameter and the UHMWPE cup wall thickness. The wear factors were determined from the simulator testing of 28 mm diameter cups. The maximum contact pressure was found to decrease with the increase of head diameter up to 48 mm, corresponding to the decrease in the cup wall thickness for a fixed outside diameter of the cup. Volumetric wear rate was predicted to increase as the head size increased for the conventional UHMWPE, as well as the cross-linked UHMWPE, although at a much lower rate for the latter due to the smaller wear factor.