无束缚系统效应时人体弹射过载耐力的测定

 本工作采用电子振荡线路模型对人体弹射过载耐力进行研究。人体是弹性体,他受到弹射力作用后的运动规律与电子振荡线路的电流运动相似,都可用相同的微分方程表达,只要它们的固有频率和阻尼比相同,电子模型即可代替人体进行实验。电子模型主要参数为带宽0～100多Hz,主固有频率10.5Hz,阻尼比0.3。将模拟的弹射信号输入到模型中去,即可得输出信号,它的波幅即代表作用在人体上的过载值,然后根据人体脊椎骨耐压强度,即可获得输入波形与耐力之间的关系。通过一系列实验,求得输入不同波形时人体的耐力数据和耐力曲线。

DETERMINATION OF HUMAN ENDURANCE TO CATAPULT OVERLOAD WITHOUT THE EFFECT OF RESTRAINT SYSTEM

In this paper electric circuit model was developed for experimental approach to study the human endurance to ejection. The human body is considered as an elastic body of single degree of freedom with low damping ratio. Its mechanical motion after the action of ejection force is similar to the current motion in the circuit of an electric oscillator. Their motion can be expressed by the same differential equation. When their natural frequency and damping ratio are the same, the electric oscillatory circuit can be used for experiments instead of human body. Natural frequency of 10.5Hz and damping ratio of 0.3 were selected for the electric model. Having transfered square waves, sine waves, triangle waves, trapezoid waves, discrete waves and overlapping waves into the electric circuit model, the output wave can be obtained. According to the amplitude of the wave, we can get the ratio value of input to output waves. If we know the amplitude of input wave, we can calculate the amplitude of the output wave from the ratio. The value of amplitude of output wave represents the magnitude of ejection overload acting on the human body. If we know the endurance capability to compressive stress of the vertebral bone, we can predicate the human endurance to ejection overload. According to this principle we have plotted the curve of human endurance vs. ejection overload.