Dynamic Analysis and Stress in Human Body due to Motion

研究了人体在跳跃至坚硬表面时减小垂直加速度的减震机理。建立了带连杆关节的人体下肢动力学模型。肌肉模型由收缩单元、串联弹性单元和粘性单元组成，并进行了实验和理论研究。以人体与工具的耦合运动为例，从理论上研究了击球对手腕和肘部的作用力和力矩。建立了球、球拍和手臂的动力学模型，计算了其振型和脉冲响应。通过将球拍设计成击球点为结点或球拍与球拍的固有频率重合，可以减小球拍的受力。对天然牙和骨内种植体进行了动力学分析，并研究了牙齿和骨骼周围的应力分布，以找到最佳的医疗治疗方案。

The shock absorbing mechanism of human body to minimize the vertical acceleration during jumping down to a hard surface was investigated. The dynamic model of human lower limb was built with a link joint. The muscle model was consisted of a contractile element, a series elastic element and a viscous element, and the experimental and theoretical investigations were carried out. The results showed that the shock could be absorbed passively by deep bending, and it could be absorbed more actively by bending motion of knees.As an example of coupled motion of a human body and a tool, the forces and moment in the wrist and the elbow caused by striking tennis ball were theoretically investigated. The dynamic model of a ball, a racket and an arm were formulated, and the modes of vibration and impulse response were calculated. The forces can be decreased by designing the racket such that the striking point becomes the nodal point or the natural frequency of the ball and racket coincides each other.The dynamic analysis of the natural teeth and endosseous implant were also carried out, and stress distribution around teeth and bone were investigated in order to find the optimum medical treatment.