多点输入下大跨空间网格结构的非平稳响应分析

将地面运动加速度表示为调制函数和零均值的平稳随机函数的乘积,并与虚拟激励法相结合,计算了大跨空间网格结构在这种激励下的时变功率谱和时变方差响应,并考查了多点输入和一致输入下结构非平稳响应的差异和多点输入下结构平稳和非平稳响应的差异以及视波速、结构跨度和阻尼比等对其差异的影响.同时,计算还表明虚拟激励法是一种高效且精确的方法,非常适合分析大跨度空间网格这样复杂结构在多点输入下的非平稳随机地震响应.

Non-Stationary Seismic Response for Long-Span Space Lattice Structures Under Multiple Support Excitation

The ground motion acceleration is expressed as the product of the modulation function and stationary random function with zero mean value;the time-dependant power spectrum and displacements response variance of joints are accurately computed with the pseudo excitation method,and the difference and change order of the structure response are studied generally under multiple support excitation and simple support excitation.Some important conclusions about the effect of apparent velocity,the span and damping ratio on the seismic response are drawn and provide theoretic foundation for long-span space structures.The calculation shows that the pseudo excitation method is efficient and precise in the seismic response analysis of such complicated structures as long-span space lattice structures under multiple support excitation.