Adaptive finite element simulation of fretting wear and fatigue in a taper junction of modular hip prosthesis.

Modular taper junctions are commonly used in total hip arthroplasty to offer a wide range of intraoperative choices to surgeons. The damage at the taper surfaces can lead to the implant failure either by material removal (wear) or by cracks nucleation (fatigue). This paper presents a methodology based on the finite element approach to study both fretting wear and fatigue, taking into account their interaction in the modular taper. The modified Archard's law was employed to compute wear depth and the corresponding volume loss while the fatigue life was predicted using two critical plane fatigue parameters (Smith-Watson-Topper and Fatemi-Socie). An adaptive meshing technique was implemented to take into account the geometry changes and the material removal effect on fatigue life. The methodology developed was discussed and validated against available experimental data from the literature. In this case considered, a transition from a partial slip regime to a large slip one, which is mainly controlled by the contact slip amplitude, was found to reduce the fatigue life and a critical slip value was identified. This provides an efficient tool for an in-depth understanding of fretting in taper junctions and for future design.