Ekevad M, Lundberg B
Industrial Development Centre, Skellefteå, Sweden.
J Biomech. 1997 Mar;30(3):259-64. doi: 10.1016/s0021-9290(96)00131-5.
An impact process similar to pole-vaulting is studied, viz., the impact in a vertical plane between the bottom end of a slightly curved elastic bar (pole), with a point mass (vaulter) at the top end, and a rigid support (pole box). Before impact, the velocity of the pole and the vaulter forms a certain angle (take-off) with the horizontal ground. Finite element calculation of the trajectories of the vaulter are carried out, and a performance figure, defined as the ratio between the maximum potential energy of the vaulter and the initial kinetic energy of the vaulter and the pole, is determined as a function of dimensionless parameters. As the vaulter remains passive during the vault, in contrast to a real vaulter, this performance figure is also the efficiency of conversion of the initial kinetic energy to the achieved potential energy in the vault. It is shown that, under normal pole-vault conditions, there exists a maximum performance figure with respect to pole length and stiffness. For an initial velocity and a body mass which are representative of an elite pole-vaulter, the maximum performance figure 0.87 is obtained for a pole with length 5.5 m.
研究了一种类似于撑杆跳的撞击过程，即：在垂直平面内，顶端带有质点（撑杆跳运动员）的微弯弹性杆（撑杆）底端与刚性支撑（撑杆盒）之间的撞击。撞击前，撑杆和撑杆跳运动员的速度与水平地面成一定角度（起跳角）。对撑杆跳运动员的轨迹进行了有限元计算，并确定了一个性能指标，该指标定义为撑杆跳运动员的最大势能与撑杆跳运动员和撑杆的初始动能之比，并将其作为无量纲参数的函数。由于与实际的撑杆跳运动员不同，撑杆跳运动员在撑杆跳过程中保持被动状态，因此该性能指标也是初始动能在撑杆跳过程中转化为所达到的势能的效率。结果表明，在正常撑杆跳条件下，相对于撑杆长度和刚度存在一个最大性能指标。对于代表优秀撑杆跳运动员的初始速度和体重，长度为5.5 m的撑杆可获得最大性能指标0.87。
