Experimental and numerical investigations of factors influencing bone fracture tolerance

本研究致力于建立综合损伤标准和损伤预测有限元(FE)模型，重点研究小腿损伤。伤害标准被各种行业(例如汽车、国防)用来评估保护系统，但历史上过于简单化。此外，计算机模型通常用于评估骨折风险，但几乎没有做过确保骨骼被正确建模的工作。小腿损伤在事故中很常见，可能会对生活质量产生重大的长期影响。因此，有必要改进损伤标准和增强的数值模型，以更好地了解这些损伤并评估新的保护技术的潜力。负荷率和小腿姿势的影响是影响损伤风险的两个重要因素，但仍有待调查。通过身体标本的实验测试，将制定新的损伤标准，包括载荷持续时间、腿部角度和脚踝位置的影响。这将允许对脚架和能量衰减材料等设备的保护能力进行更适当的评估。由“碰撞试验假人”测量的相应载荷将被确定，从而为行业安全评估提供指导。此外，还将开发一种仪器化的靴子，以提供一种手段来评估脚/脚踝的受伤风险，这是一个尚未安装仪器化的区域。将进行研究，以确定为损伤预测计算机研究建立骨骼模型所需的最佳参数，并将开发小腿的数值模型，并根据上述测试数据进行验证。影响受伤风险的因素尚不清楚。通过进一步制定用于评估安全措施的伤害标准，可以减少衰弱性创伤的发生率。这将使受保护的人口得到更好的保护，并减少参与创伤事件的人的长期影响。

This research is concerned with the development of comprehensive injury criteria and injury-predicting finite element (FE) models, with a focus on the lower leg. Injury criteria are used by a variety of industries (e.g., automotive, defence) to evaluate protective systems, but have historically been oversimplified. Furthermore, computer models are commonly used to evaluate fracture risk, but little work has been done to ensure that bone is properly modeled. Lower leg injuries are frequent in accidents and can have significant long-term effects on quality of life. As such, there is a need for improved injury criteria and enhanced numerical models to better understand these injuries and assess the potential of novel protective technologies.The effect of loading rate and lower leg posture are two significant factors that will influence injury risk, but have yet to be investigated. Through experimental testing of cadaveric specimens new injury criteria will be developed that include the effect of load duration, leg angle and ankle position. This will permit more appropriate evaluation of devices such as footrests and energy attenuating materials for their protective capabilities. Corresponding loads measured by 'crash test dummies' will be determined, thus providing guidelines to industry for safety assessments. As well, an instrumented boot will be developed to provide a means to evaluate injury risk to the foot/ankle, a region not yet instrumented. Studies will be conducted to determine the optimal parameters needed to model bone for injury predicting computer studies, and a numerical model of the lower leg will be developed and validated against the aforementioned test data.The factors which influence injury risk are not well understood. By further developing the injury criteria used to evaluate safety measures, the prevalence of debilitating traumatic injuries can be reduced. This will result in a better protected population and reduced long term effects for those involved in traumatic events.