摘要
大跨空间结构振型频率密集、高阶振型效应显著,结构地震反应复杂。为准确计算空间结构地震反应,往往需要考虑大量振型反应贡献,计算成本较大。若可快速识别对结构反应贡献较大的振型,可有效提高计算效率。鉴于此,提出一种基于反应谱的主振型遴选方法,以识别结构在地震作用下的主导振型。首先,基于非耦联振型分析理论,推导建立各振型关于位移反应和内力反应贡献指标;其次,基于反应谱理论推导建立关于各反应的主振型识别准则;最后,根据各振型贡献值和给定的遴选阈值确定结构的主导振型。不同矢跨比的网壳算例结果表明,低矢跨比的网壳的高阶振型贡献不可忽略;本文所提方法识别结构主振型准确、高效,可针对结构位移和内力反应需求进行振型遴选。
The seismic response of large span spatial structure is complicated due to its dense natural frequencies and higher mode effect.In order to obtain accurate response result of large span spatial structure,hundreds of modes should be taken into account,which increase the computing cost.In this paper,a spectrum-based mode selection method is proposed to identify dominated modes of spatial latticed structures under seismic excitation.Firstly,two types of dominated modes are defined according to modal contribution of displacement and force response.Secondly,based on response spectrum,each modal contribution on specific response is qualified.Thirdly,the dominated modes are selected according to each modal contribution value and given threshold value.Numerical examples of spherical reticulated shells are built to verify the applicability of the proposed method.The resultsfrom reticulated shells of different rise-span ratios show that the contribution of higher order modes of the shell with low rise-span ratio cannot be ignored.The proposed method is accurate and efficient in identifying the dominated modes of structures,and can be used to select the mode according to the demands of structural displacement and internal force response.
作者
黄青隆
罗永峰
白洁
杨燕
申雨
唐伟耀
HUANG Qinglong;LUO Yongfeng;BAI Jie;YANG Yan;SHEN Yu;TANG Weiyao(China Construction Eighth Engineering Division Co.,Ltd.,Shanghai 200122,China;Civil Engineering College,Tongji University,Shanghai 200092,China)
出处
《建筑结构》
北大核心
2023年第S02期534-540,共7页
Building Structure
基金
国家自然科学基金项目:大跨空间结构地震反应分析方法研究(51378379)。
关键词
主振型遴选
大跨空间结构
反应谱
遴选阈值
dominated mode selection
spatial latticed structures
response spectrum
selection threshold value
