Constitutive Model for Polyethylenes in Joint Components

接头部件中聚乙烯的本构模型

• 批准号: 6330781
• 负责人: CLARE M RIMNAC
• 金额: $ 26.15万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6330781
• 关键词: biomaterial evaluation; calorimetry; density gradient ultracentrifugation; hip prosthesis; joint prosthesis; knee; mechanical stress; orthopedics; polyethylenes

DESCRIPTION (Verbatim from the Applicant): Wear damage to the articulating surfaces of ultra high molecular weight polyethylene (UHMWPE) joint replacements continues to be recognized as a significant clinical problem limiting the longevity of total joint replacements. It has been shown that the cyclic large strain mechanical behavior of UHMWPE affects the damage mechanisms of hip and knee components; however, there is still a lack of quantitative understanding regarding how changing the state of deformation affects the mechanical response of either conventional UHMWPE, or the highly cross-linked UHMWPEs recently introduced into clinical use for total hip arthroplasty and under consideration for use in total knee arthroplasty. There is a need for better predictions of damage and wear from numerical analyses of UHMWPE components. However, to do so, a constitutive model for UHMWPE that accounts for multiaxial and cyclic behavior must first be developed, validated and implemented. Our global hypothesis is that a physically based constitutive theory will more accurately describe the large deformation mechanical behavior of UHMWPE structures under multiaxial and cyclic loading conditions than the material models in current use. It is proposed to: (1) model three UHMWPE materials (virgin, gamma radiation sterilized in nitrogen and gamma radiation cross-linked) using physically-based constitutive theories for polymers and compare the results to the current material model (isotropic plasticity); (2) determine which constitutive theory provides the best model for each UHMWPE material by determining which theory best predicts experimental results; and (3) implement the best constitutive theory into hip and knee implant finite element models to predict the time-dependent multiaxial stress and strain states. The next step will be to utilize the developed tools from this study to predict wear, surface damage (and gross damage) from in vitro hip and knee simulator studies, and ultimately, from in vivo use. The goal is to improve the long-term performance of UHMWPE joint components, regardless of UHMWPE formulation, through significantly improved numerical modeling of components prior to implantation.

描述（申请人逐字记录）：关节磨损损坏 超高分子量聚乙烯 (UHMWPE) 接头表面 替代品仍然被认为是一个重大的临床问题 限制全关节置换术的寿命。已经表明， UHMWPE 的循环大应变力学行为影响损伤机制 髋部和膝部部件；但仍缺乏定量的 了解改变变形状态如何影响 传统 UHMWPE 或高度交联的机械响应 UHMWPE 最近被引入临床用于全髋关节置换术和 正在考虑用于全膝关节置换术。有必要 通过 UHMWPE 的数值分析更好地预测损坏和磨损 成分。然而，要做到这一点，需要一个 UHMWPE 本构模型来解释 对于多轴和循环行为必须首先开发、验证和 实施的。我们的全局假设是基于物理的本构 理论将更准确地描述大变形力学行为 UHMWPE 结构在多轴和循环载荷条件下的性能优于 当前使用的材料模型。建议：（1）型号三UHMWPE 材料（原始材料、在氮气和伽马辐射中灭菌的材料） 交联）使用基于物理的聚合物本构理论和 将结果与当前材料模型（各向同性塑性）进行比较； (2) 确定哪种本构理论为每种 UHMWPE 提供最佳模型 通过确定哪种理论最能预测实验结果来提供材料；和 (3) 将最佳本构理论应用到髋关节和膝关节植入有限元中 用于预测随时间变化的多轴应力和应变的单元模型 州。下一步将利用本研究开发的工具 预测体外髋关节和膝关节的磨损、表面损伤（和总体损伤） 模拟器研究，最终来自体内使用。目标是改善 UHMWPE 接头部件的长期性能，无论 UHMWPE 材质如何 通过显着改进组件的数值建模来制定 植入前。