BRIGE: Patterned Microtexture to Create Fluid Film Lubrication at Low Sliding Velocities in Prosthetic Knee Joints

这项扩大参与研究启动助学金(Brige)赠款为具有图案微纹理的假肢膝关节植入物轴承表面的设计提供资金。这项研究的主要目标是通过在低关节滑动速度下创建流体动力润滑来减少摩擦和磨损，从而与最先进的光滑种植体相比延长种植体的耐用性。具有图案微纹理的假体膝关节滑动部件的模型将使用有限差分公式来实现。微结构的定义参数将进行优化，以最大限度地提高轴承承载能力和轴承表面之间的分离。该模型将考虑润滑剂(滑液)的非牛顿性质以及在步态过程中轴承表面之间的可变间距。激光表面纹理将被用来制造图案化的微纹理。为了验证模型的有效性，并通过实验比较了微纹理假体和光滑假体膝关节轴承表面的摩擦磨损情况，本研究将建立一个具有优化图案的假体膝关节假体原型，这项研究将为在非牛顿润滑剂存在的情况下，在低滑动速度、可变滑动速度下微纹理对从边界润滑向流体动力润滑转变的影响提供重要的见解。具体地说，这项研究的结果将有助于通过显著减少摩擦和磨损来提高假体膝关节植入物支承表面的耐久性。这可能标志着新一代假体植入物的开始，其耐用性大大提高，以服务于老龄化人口并降低医疗成本。此外，这项研究也将适用于减少其他植入物的摩擦和磨损，如髋关节和肩部植入物。在该项目期间，将通过K-12外展和本科生研究促进来自代表性不足群体的学生的参与。在犹他大学为女高中生举办的年度Hi-Gear夏令营将提供与摩擦有关的互动模块和课程。此外，一个演示套件将成为发现工程展示的一部分，该展示参观盐湖城大都市区的高中。

This Broadening Participation Research Initiation Grant in Engineering (BRIGE) grant provides funding for the design of prosthetic knee implant bearing surfaces with a patterned microtexture. The primary goal of this research is to extend implant durability compared to state-of-the-art smooth implants by creating hydrodynamic lubrication at low joint sliding velocities to reduce friction and wear. A model of the sliding components of a prosthetic knee joint with patterned microtexture will be implemented using a finite difference formulation. The defining parameters of the microtexture will be optimized to maximize the bearing load carrying capacity and the separation between the bearing surfaces. The model will account for the non-Newtonian nature of the lubricant (synovial fluid) and the variable spacing between the bearing surfaces during gait. Laser surface texturing will be used to fabricate the patterned microtexture. A prototype prosthetic knee implant with an optimized, patterned microtexture design will be built to validate the model and experimentally compare friction and wear of microtextured and smooth prosthetic knee bearing surfaces.This study will provide critical insight on the effect of microtexture for the transition from boundary lubrication to hydrodynamic lubrication at low, variable sliding velocities in the presence of a non-Newtonian lubricant. Specifically, the results of this research will contribute to improving the durability of bearing surfaces of prosthetic knee implants by drastically reducing friction and wear. This could mark the beginning of a new generation of prosthetic implants with much improved durability, to serve an aging population and reduce health care costs. By extension, this research will also apply to reducing friction and wear in other implants, such as hip and shoulder implants. During this project, participation of students from underrepresented groups will be promoted through K-12 outreach and undergraduate research. An interactive module and curriculum related to friction will be contributed to the annual Hi-GEAR camp at the University of Utah for female high school students. Additionally, a demo-kit will be part of the Discover Engineering Display, which visits high schools in the Salt Lake City metro area.