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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。
For the large-span floor cover with frequent modal frequencies, there are often many modes that can be excited by pedestrian loads to generate resonance. At present, there is no perfect vibration control method for such problems. Based on the TMD (Tunable Mass Damper) and the frequency distribution of the load amplitude of the pedestrian crossing, aiming at the conditions of the load excitation which is related to the shape of each floor of the floor and can stimulate the most unfavorable vibration of the floor, The design method of comprehensive control of multiple vibration mode of floor with a limited number of TMDs is proposed. Taking the damped mass damper (MTMD) design of a large span floor as an example, the finite element method is used to simulate the floor reaction under the action of actual pedestrian and test the effect of vibration control. Then the multi-modal optimization method is compared And the MTMD designed by the single-modal optimization method to control the vibration modes of the floor vibration modes with different density distributions. The results show that considering the multi-modal superposition design of MTMD can control the floor vibration modes of the entire passenger excitation frequency range synthetically and achieve the consistency of the peak response of each floor resonance mode and the distribution of modal frequencies Floor vibration damping has better applicability. In addition, the unfavorable vibration of the floor is controlled not only by the low-order mode, but also by the pedestrian bank.