Abstract Ball-in-socket metal on metal (MOM) contacts were analysed using the Abaqus Finite Element package to simulate dry contact between the acetabular cup and the femoral head. Different cup thicknesses of 4, 6, 8, and 10 mm were considered using a polyurethane foam block support system. Elastohydrodynamic lubrication (EHL) analyses were developed for the contacts using three different approaches to specify the contact. These were (i) A simple model based on the radii of relative curvature, (ii) An equivalent contact model developed so that its dry contact area and maximum pressure replicated the values obtained from the FE analysis, and (iii) A modified version of (ii) that also ensured equivalence of the gap shape outside the contact area. Published in vivo information for the hip joint contact forces over the walking cycle was used to specify the operating conditions for the EHL analysis. The analysis method was found to be effective for all points of the walking cycle for cases where the cup thickness exceeded 5 mm and modelling approach (ii) was identified as satisfactory. For a cup thickness of 4 mm, membrane action began to emerge in the FE analyses so that such contacts behaved in a different way.

中文翻译：

---

接触区外间隙对金属对金属全髋关节置换润滑的影响

摘要 使用 Abaqus 有限元软件包对金属对金属球窝 (MOM) 触点进行分析，以模拟髋臼杯和股骨头之间的干接触。使用聚氨酯泡沫块支撑系统考虑了 4、6、8 和 10 毫米的不同杯厚。使用三种不同的方法来指定接触，对接触进行弹性流体动力润滑 (EHL) 分析。它们是 (i) 基于相对曲率半径的简单模型，(ii) 开发等效接触模型，使其干接触面积和最大压力复制从有限元分析中获得的值，以及 (iii) (ii) 这也确保了接触区域外间隙形状的等效性。已发布的步行周期内髋关节接触力的体内信息用于指定 EHL 分析的操作条件。对于罩杯厚度超过 5 毫米且建模方法 (ii) 被确定为令人满意的情况，该分析方法对步行周期的所有点均有效。对于 4 毫米厚的杯，有限元分析中开始出现膜作用，因此这种接触以不同的方式表现。