A variable mass model for describing load impulses due to periodic jumping
A variable mass model for describing load impulses due to periodic jumping
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DOI：
10.1016/j.engstruct.2007.11.017
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发表时间：
2008-06
影响因子：
5.5
通讯作者：
S. Nhleko;A. Zingoni;P. Moyo
中科院分区：
文献类型：
--
作者：
S. Nhleko;A. Zingoni;P. Moyo
本文回顾了目前的哲学描述跳跃的人对结构的振动行为的影响。集中在半正弦脉冲力模型，这是包括在BS 6399-96实践代码的跳跃人类负载的描述，它被发现，该模型是无法预测的正确形状的负载脉冲或其主谐波的跳跃频率是显着小于2赫兹。本文提出了一种新的通用模型，它包括脉冲形状因子，是基于处理的结构跳线系统作为一个伪变质量系统。通过考虑最近的研究结果在技术文献中，它表明，所提出的模型可以用来描述所有可达到的跳跃频率的负载脉冲，通过选择适当的脉冲形状因子。在实验验证中，发现当人类受试者以1 Hz跳跃时，基频为7.1的结构的加速度响应由跳跃频率的二次谐波（忽略共振频率）主导，证实了负载脉冲由该跳跃频率的二次谐波主导，如文献中所报道的。利用该模型对跳载冲击进行仿真，也预测了加速度响应的相同模式，验证了该模型的准确性。
This paper reviews the current philosophy for describing the effects of jumping humans on the vibration behaviour of structures. Focusing on the Semi-sinusoidal pulse force model, which is included in the BS 6399-96 code of practice for the description of jumping human loads, it was found that this model is unable to predict the correct shape of the load impulse or its dominant harmonic for jumping frequencies that are significantly less than 2 Hz. This paper presents a new general model, which incorporates impulse shape factors and is based on the treatment of the structure–jumper system as a pseudo-variable mass system. By considering recent findings in the technical literature, it is shown that the proposed model can be used to describe load impulses for all attainable jumping frequencies, by choosing appropriate impulse shape factors. In the experimental verification, the acceleration response of a structure with a fundamental frequency of 7.1 was found to be dominated by the second harmonic of the jumping frequency (ignoring the resonant frequencies) when a human subject jumped at 1 Hz, confirming that the load impulse is dominated by the second harmonic for this jumping frequency, as reported in the literature. The simulation of the jumping load impulse using the proposed model also predicted the same pattern in the acceleration response, verifying that the model is accurate.