人行荷载作用下大跨楼盖多模态振动控制方法研究

对于模态频率密集分布的大跨楼盖，往往存在多个模态能够被人行荷载激发产生共振，目前对此类问题尚无完善的振动控制方法。以大跨楼盖为对象，采用调谐质量阻尼器（TMD），基于人行荷载幅值的频域分布，针对与楼盖各共振模态形状相关并能激发楼盖最不利振动的荷载激励条件，提出了采用有限数量TMD对楼盖多个振动模态进行综合控制的设计方法。以某大跨楼盖的多重调谐质量阻尼器（MTMD）减振设计为例，首先采用有限元方法模拟实际人行作用下的楼盖反应并检验振动控制的效果，然后对比了多模态优化方法和单模态优化方法设计的MTMD对频率不同疏密程度分布的楼盖振动模态进行减振控制的效率。结果表明，考虑多模态叠加设计MTMD能够对整个人行激励频带范围内的楼盖振动模态进行综合控制，实现了楼盖各个共振模态处响应峰值的一致性，对模态频率分布较密集楼盖的减振具有更好的适用性。另外，楼盖的不利振动不仅由低阶模态控制，人行激励下楼盖高阶模态共振同样产生非常不利的影响。

Integrated control for multi-modal floor vibration under-human walking

This paper investigated the multi-modal vibration control of floor under human walking. Based on the load magnitude curve in the frequency domain extracted from the analytical formula of human walking, the component mode synthesis (CMS) method was used to assess the dynamic response of the floor equipped with multiple tuned mass dampers (MTMD). With the maximum floor acceleration as the optimization objective calculated by CMS, the genetic optimization algorithm was chosen to obtain the optimal MTMD. Subsequently, the superior vibration suppressing efficiency of the proposed MTMD was presented by finite element analysis simulating the loading procedure of human walking on the floor. The numerical simulation shows that the excessive floor vibration is not always controlled by the fundamental modal resonance, while sometimes the high-order modal resonance induced by the high-order (2nd and 3rd) harmonics may compromise the floor dynamic serviceability. Comparison of the acceleration for the floor equipped with MTMD designed by the proposed multi-modal and the single-modal optimization shows that the proposed MTMD is capable of capturing these possible high-order resonant modes and lowering each modal response of the controlled modes to the same level while the single-modal optimization owns uneven responses of the controlled modes. Thus, the proposed MTMD has better vibration control performance compared to its counterpart designed by the traditional design methods, especially for the floor with closed-spaced modes.