Non‐spherical shape optimization of artificial hip joint based on elastohydrodynamic lubrication analysis

Abstract

Structural optimization design is a promising way to further promote the lubrication performance of the artificial hip joint (AHJ). In this work, a non‐spherical shape optimization design strategy for the femoral head is firstly proposed. The generatrix, the line rotated about an axis that generates the bearing surface of the femoral head, is characterized based on a third‐order Bezier curve. The performance of the AHJ under steady‐state condition is analyzed by solving the governing equations of the elastohydrodynamic lubrication problem, and the minimum lubricating film thickness of the AHJ is maximized by adjusting the positions of four control points of the Bezier curve based on the simulated annealing method. The results show that, when compared with the standard spherical femoral head, the optimized non‐spherical femoral head can significantly improve the minimum thickness and reduce the maximum pressure of the lubricating film of the AHJ. Through the analysis of the optimization process, the results further reveal that the shape of the femoral head has a direct impact on the thickness distribution of the lubricating film. This research will provide guidance and theoretical support for novel design of AHJs.