A two-dimensional finite element model for frictional heating analysis of total hip prosthesis

Previous investigations of wear test using hip simulators have shown the pr opensity of frictional heating during articulation of total hip prosthesis. The observations also indicated that the elevated temperature is sufficien t to influence the rate of wear, fatigue, creep, and oxidative degradation of the ultra-high molecular weight polyethylene (UHMWPE) liner and to alter its mechanical properties. Moreover, additional axial and radial deformati on of UHMWPE may be introduced due to the rise of temperature. This change in configuration in tam affects contact characteristics at the interface of the cup and the head. Only a fully coupled thermomechanical analysis allow s for the study of the problem in its complexity, i.e. to solve for the dis placement field and temperature field, simultaneously. A fully thermomechanical coupled finite element analysis model of total hip prosthesis-was developed. The model simulating the wear test in a hip simu lator was used to evaluate the transient contact stresses and to predict th e rise of temperature due to the friction for varying applied load, sliding speed and frictional coefficient. Results indicated that the temperature e levated due to friction is significantly affected by these factors. The ana lysis serves to further understand the tribological behavior of UHMWPE and the influence of temperature on contact interaction and wear process. (C) 2 001 Elsevier Science B.V. All rights reserved.