空间网格结构频域风振响应分析模态补偿法

大跨空间网格结构是频率密集性结构,按照模态分析法,尽管考虑多阶振型的影响有时也难以包含所有的主要贡献模态。从数值分析中可以发现,大跨空间网格结构风振分析中往往存在着一些高阶振型,它对风振响应的贡献比较大,但由于其频率高往往很容易被忽略。本文根据模态对系统应变能的贡献,提出了一种有效的选取主要贡献模态的方法,为了克服包含所有主要贡献模态的困难,本文提出了一种简单的方法来补偿由于高阶模态遗漏而产生的误差,并通过一个网壳的算例对所提出方法的有效性进行了验证。

WIND-INDUCED RESPONSE OF SPATIAL STRUCTURES WITH MODE COMPENSATION IN FREQUENCY DOMAIN

Large span spatial lattice structures are characterized by the existence of many natural frequencies in a narrow frequency range. Consequently, with the modal analysis method, it is difficult to contain all significant contribution modes. It has been shown that some high order modes, which contribute to wind response significantly, are likely to be overlooked because of their higher modal order. From a view point of contributions of modes to the strain energy of the system, it is suggested to make an efficient selection of dominant modes in this paper. A simple and effective method to compensate the errors owing to leaving out some high order modes is proposed. The effectiveness of the proposed method is verified through a numerical simulation of the wind response of a spherical dome.