PERMANENT DEFORMATION OF COMPACT BONE

已经表明，人类密质骨具有以下能力： 塑性（永久性）变形显著量时， 加载，虽然控制微结构变形 机制尚未明确建立。 的目的 该项目旨在研究以下方面的相对贡献： 微观变形机制 人体密质骨的永久变形。 这一目标将 通过检查假设，宏观 人体密质骨的永久变形 静态载荷货车被模拟为试验和材料的函数 变量 对于金属和陶瓷， 已经通过模拟这种影响来确定机制， 宏观蠕变变形变量（时间- 应用常数引起的应变的相关变化 负载）。 因为人类密质骨已经被证明 经历类似于金属的典型蠕变响应， 陶瓷，将应用相同的方法。 的影响 温度、应力、试样方向和试样尺寸 将确定密质人骨的蠕变行为。 结果将用于确定活化能值 微观结构变形机制。 这些值可以 与过程的能量需求相关，例如 胶原粘合断裂或骨水泥线断裂。 此外，本发明还提供了一种方法， 标本相对于骨的方向和尺寸 微结构将在进一步的努力中变化，以确定 微观结构变形机制的贡献 宏观变形响应 据信这 这种方法将成功地导致一个假设的发展 人体组织的微观结构变形机制 骨可以从其宏观模型中识别， 永久变形行为

It has been shown that human compact bone has the ability to plastically (permanently) deform a significant amount when loaded, though the controlling microstrural defomation mechanisms have not be clearly established. The objective of this project is to investigate the relative contribution of microstructural deformation mechanisms to the macroscopic permanent deformation of compact human bone. This goal will be achieved by examining the hypothesis that the macroscopic permanent deformation of compact human bone subjected to static loads van be modelled as a function of test and material variables. For metals and ceramics, microstructural deformation mechanisms have been identified by modelling the effect of such variables on the macroscopic creep deformatin (the time- dependent change in strain caused by the application of a constant load). Because human compact bone has been shown to experience a classic creep response like that of metals and ceramics, the same approach will be applied. The effect of temperature, stress, specimen orientation and specimen size on the creep behavior of compact human bone will be determine. The results will be used to determine the activation energy values for microstructural deformation mechanisms. These values may be correlated to the energy requirements for processes such as collagen bond disruption or cement line fracture. In addition, specimen orientation and size with respect to the bone microstructure will be varied in a further effort to determine the contribution of microstructural deformation mechanisms to the macroscopic deformation response. It is believed that this approach will successfully lead to the development of a hypothesis that microstructural deformation mechanisms of human compact bone can be identified from the model of its macroscopic permanent deformation behavior.