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为研究鞍形网壳在地震动激励下的振型反应规律,将结构地震作用表达为仅与时间变量有关的随机过程,给出频域内结构准静力响应、共振响应和耦合响应的定义及计算式;计算两组地震动功率谱作用下,鞍形网壳结构的位移响应谱,包括准静力响应谱、共振响应谱和耦合响应谱,总结结构位移响应的频域分布特性,分析准静力响应及共振响应之间的相关性;提出改进的振型叠加法,并给出数值算例。研究结果表明,对应一定的地震动输入功率谱,鞍形网壳结构的响应主要是特定频率区段的振型响应。在z向地震作用下,准静力响应和共振响应的耦合效应对总响应的影响不可忽略,而在x、y向地震作用下,这一效应可忽略。计算结果表明,所提出的改进振型叠加法计算效率和求解精度优于传统振型叠加法。
In order to study the mode response of the saddle-shaped reticulated shell under the earthquake excitation, the seismic action of the structure is expressed as a stochastic process related only to the time variation. The definitions of the quasi-static response, the resonance response and the coupling response of the structure in the frequency domain are given. Calculate the displacement response spectrum of the saddle-shaped reticulated shell under the action of two groups of ground motion power spectrum, including the quasi-static response spectrum, the resonance response spectrum and the coupling response spectrum, summarizes the frequency-domain distribution characteristics of the structure displacement response, Static response and resonance response of the correlation between; proposed improved modal superposition method, and gives numerical examples. The results show that the response of the saddle-shaped reticulated shell structure is mainly the mode response of a specific frequency section corresponding to a certain ground motional input power spectrum. Under the action of z earthquake, the coupling effect between quasi-static response and resonance response can not be neglected. However, this effect can be neglected under the action of x- and y-direction earthquakes. The calculated results show that the proposed method improves the computational efficiency and accuracy of the proposed method in comparison with the traditional modal superposition method.