Instituto Politécnico Nacional - Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Querétaro, Cerro Blanco No. 141, 76090 Querétaro, Qro., Mexico.
Corporación Mexicana de Investigación en Materiales, S.A. de C.V., Ciencia y Tecnología N° 709, Col. Saltillo 400, C.P. 25290 Saltillo, Coah., Mexico.
J Mech Behav Biomed Mater. 2018 Jun;82:248-256. doi: 10.1016/j.jmbbm.2018.03.028. Epub 2018 Mar 27.
Friction is the natural response of all tribosystems. In a total knee replacement (TKR) prosthetic device, its measurement is hindered by the complex geometry of its integrating parts and that of the testing simulation rig operating under the ISO 14243-3:2014 standard. To develop prediction models of the coefficient of friction (COF) between AISI 316L steel and ultra-high molecular weight polyethylene (UHMWPE) lubricated with fetal bovine serum dilutions, the arthrokinematics and loading conditions prescribed by the ISO 142433: 2014 standard were translated to a simpler geometrical setup, via Hertz contact theory. Tribological testing proceeded by loading a stainless steel AISI 316L ball against the surface of a UHMWPE disk, with the test fluid at 37 °C. The method has been applied to study the behavior of the COF during a whole walking cycle. On the other hand, the role of protein aggregation phenomena as a lubrication mechanism has been extensively studied in hip joint replacements but little explored for the operating conditions of a TKR. Lubricant testing fluids were prepared with fetal bovine serum (FBS) dilutions having protein mass concentrations of 5, 10, 20 and 36 g/L. The results were contrasted against deionized, sterilized water. The results indicate that even at protein concentration as low as 5 g/L, protein aggregation phenomena play an important role in the lubrication of the metal-on-polymer tribopair. The regression models of the COF developed herein are available for numerical simulations of the tribological behavior of the aforementioned tribosystem. In this case, surface stress rather than film thickness should be considered.
摩擦是所有摩擦系统的自然反应。在全膝关节置换（TKR）假体中，由于其组成部分的复杂几何形状以及按照 ISO 14243-3:2014 标准运行的测试模拟装置的几何形状，其摩擦系数（COF）的测量受到阻碍。为了开发用胎牛血清稀释液润滑的 AISI 316L 钢与超高分子量聚乙烯（UHMWPE）之间的 COF 预测模型，根据 ISO 14243-3:2014 标准规定的关节运动学和加载条件，通过赫兹接触理论将其转换为更简单的几何设置。通过将不锈钢 AISI 316L 球加载到 UHMWPE 盘的表面上来进行摩擦学测试，测试流体温度为 37°C。该方法已应用于研究整个步行周期内 COF 的行为。另一方面，蛋白质聚集现象作为一种润滑机制在髋关节置换中得到了广泛研究，但在 TKR 的工作条件下研究甚少。用胎牛血清（FBS）稀释液制备了润滑剂测试液，蛋白质质量浓度分别为 5、10、20 和 36g/L。结果与去离子、消毒水进行了对比。结果表明，即使蛋白质浓度低至 5g/L，蛋白质聚集现象在金属-聚合物摩擦副的润滑中也起着重要作用。本文建立的 COF 回归模型可用于上述摩擦系统摩擦学行为的数值模拟。在这种情况下，应考虑表面应力而不是膜厚。
