An Energy Based Method for Wear Analysis of a CrCoMo-UHMWPE and DLC-UHMWPE Couples for Hip Prosthesis

In this work, a model to evaluate the abrasive wear between two semi-cylindrical entities is presented. The entities represent the average roughness radius, of the contact surfaces formed between the femoral head and acetabular cup of a hip prosthesis. The contact couples employed in this work are CrCoMo-UHMWPE and DLC-UHMWPE. Here three different interference distances were employed: 1, 2.5 and 40 percent of the mean radius roughness of the UHMWPE. The energy method proposed here determines the maximum contact stresses, from where the maximum point of distortional energy is obtained. This is then linked to the geometry of the cylindrical entity, which then gives the initial failure point. Subsequent similar calculations provide with the trajectory of the wearing path. The percentage of the abrasive wear obtained from this method was compared to Archard’s method. It was noted that the percentage of Archard’s wear is a ten in million part from the total volume, while that the percentage of Energy’s wear is between 2.760% and 7.055%, when an interference distance S = 0.5 μm, was employed. It was also found that the CrCoMo-UHMWPE couple exhibited 22.84% of volume lost compared with the 2.95% of the DLC-UHMWPE couple.