EAGER/Collaborative Research: Mechanical Size Effects and Bone Failure

EAGER/合作研究：机械尺寸效应和骨衰竭

• 批准号: 1643116
• 负责人: Matthew Allen
• 金额: $ 7.04万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643116&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Research; Mechanical; Size

Age related bone fractures are a major concern in an aging population such as in the United States. Currently, bone mineral density (BMD) is used as an indicator of fracture risk, yet it is becoming increasingly clear that is has poor predictive ability on an individual basis. It recently has been demonstrated that bone quality is variable between people in a way that is not understood medically, but which might be understood using advanced mechanics methods. Dimensional analysis has led to the insight that there is a material lengthscale for materials that can predict fracture and fatigue damage of engineering materials. This research project is a collaboration between an advanced mechanics laboratory and an advanced bone mechanics laboratory that will create novel analytical methods for the problem of bone failure while, at the same time, the bone fracture problem will be a new challenge for the engineering analysts. This research will provide a biomechanical foundation for understanding a fundamental underlying feature of bone strength and fatigue resistance. Demonstration of the existence of an intrinsic lengthscale and its dependence on intrinsic material toughness could significantly change our fundamental understanding of how microstructured biological materials function. It also could be a seed towards developing a future bone assessment approach, which considers both bone microstructure and bone tissue properties in failure.In mechanics, dimensional analysis has led to the insight that an intrinsic lengthscale L* (a ratio of fracture toughness and strength or endurance) for a material emerges as a natural outcome of any boundary value problem of fracture and fatigue damage. When including a lengthscale in considerations of mechanical loading, the fracture/damage response becomes dependent on microstructural feature size, leading to a deterministic mechanical size effect of damage and ultimately failure. Intrinsic lengthscales have been documented experimentally for fracture experiments of bone. The research work will provide an early foundation for a new approach to the understanding of bone degradation and the severity of fracture risk and the degraded mechanical performance of aging bone which considers both bone microstructure and bone tissue properties in failure.

与年龄相关的骨折是人口老龄化（例如在美国）的一个主要问题。目前，骨矿物质密度（BMD）被用作骨折风险的指标，但越来越明显的是，它对个体的预测能力很差。最近的研究表明，人与人之间的骨骼质量存在差异，这种差异在医学上尚无法理解，但可以通过先进的力学方法来理解。 尺寸分析使人们认识到，材料的材料长度尺度可以预测工程材料的断裂和疲劳损伤。 该研究项目是先进力学实验室和先进骨力学实验室之间的合作，将为骨破坏问题创建新颖的分析方法，同时，骨折问题将成为工程分析人员的新挑战。 这项研究将为理解骨强度和抗疲劳性的基本特征提供生物力学基础。 证明内在长度尺度的存在及其对内在材料韧性的依赖性可以显着改变我们对微结构生物材料如何发挥作用的基本理解。 它还可能成为开发未来骨骼评估方法的种子，该方法考虑失效时的骨骼微观结构和骨组织特性。在力学中，尺寸分析使人们认识到内在的长度尺度 L*（断裂韧性与强度的比率）或耐久性）对于材料来说是断裂和疲劳损伤的任何边界值问题的自然结果。当考虑机械载荷时包括长度尺度时，断裂/损坏响应变得取决于微观结构特征尺寸，导致损坏和最终失效的确定性机械尺寸效应。 骨断裂实验中已经通过实验记录了内在长度尺度。 这项研究工作将为理解骨退化、骨折风险的严重性以及老化骨机械性能下降的新方法提供早期基础，该方法考虑了失效时的骨微观结构和骨组织特性。