支点和踏板位置对跳水板力学特性的影响

研究跳板的力学特性是提高跳板跳水技术水平的基础,支点选择和踏板位置是两个主要影响因素。该文采用有限元方法,建立了跳板非线性三维模型,考虑了支点的单边约束特性,对不同支点位置和踏板位置下跳板的力学特性进行了分析比较。结果表明:1)在同样的外力作用下,支点靠近跳板固定端,板前端垂直位移增大;2)在压力作用下,支点和跳板接触,压力撤销后跳板反弹,与支点分离;3)无支点约束时,跳板固有频率最小;约束支点越靠近跳板固定端,固有频率越小;运动员位置越靠近板前端,固有频率越小;4)支点位置不变时,踏板位置越靠近板前端,板前端位移越大。该文研究成果不仅可以为运动员和教练员提供定量的支点选择和踏板位置调整的理论依据,而且为进一步研究跳板运动员耦合系统的生物力学特性奠定了基础。

Influence of fulcrum and load positions on springboard mechanics

A quantitative understanding of springboard mechanics is necessary for divers and coaches to improve their performance. The fulcrum position and the load position are two primary factors which influence the board movement. This paper describes a 3-D nonlinear finite element model of a springboard which considers the undirectional constraint of the fulcrum. The dynamic properties of the springboard were analyzed with different fulcrum settings and load positions. The results showed that the board-tip vertical displacement increased when the fulcrum was set nearer the end and that the board and fulcrum kept in contact when the external force was applied but separated when the force was removed. The natural frequency of the board was lowest without the fulcrum and the natural frequency decreasesd as the fulcrum position or the load position was moved nearer the tip. The board-tip vertical displacement increased as the load moved nearer the tip. The findings provide quantitative criteria for divers and coaches to select the optimal fulcrum position and to adjust the load point.