PERMANENT DEFORMATION OF COMPACT BONE

已有研究表明，人类密质骨有能力 当发生以下情况时，塑性(永久)变形显著 加载，尽管控制微结构变形 机制尚未明确建立。这样做的目的是 该项目旨在调查以下项目的相对贡献 微观组织变形机制对宏观的影响 致密的人类骨骼的永久变形。这个目标将是 通过检验宏观的假设来实现 人致密骨在压缩载荷作用下的永久变形 静载荷可以模拟为试验和材料的函数 变量。对于金属和陶瓷，微结构变形 已经通过对这种影响的建模来确定其机制 宏观蠕变变形的变量(时间-时间) 由应用常量引起的应变的相依变化 加载)。因为人类的密质骨已经被证明 体验经典的蠕变反应，就像金属和 陶瓷业，也将采用同样的方法。的影响 温度、应力、试件方向和试件尺寸 将测定致密人骨的蠕变行为。 结果将被用来确定激活能值 用于微观结构变形机制。这些值可能 与流程的能源需求相关，例如 胶原键断裂或骨水泥线断裂。此外, 试件相对于骨骼的方向和大小 微观结构将有所不同，以进一步确定 微结构变形机制对材料力学性能的影响 宏观变形响应。据信，这一点 方法将成功地导致一个假说的发展 人体紧凑体的微观变形机制 骨骼可以从其宏观模型中识别出来。 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.