有限持时地震动对长周期结构动力响应影响.pdfVIP

有限持时地震动对长周期结构动力响应的影响 * 周瑞忠 ，吴琛 (福州大学土木工程学院，福建，福州，350002) 摘要：有限持时的实例提示我们结构的最大位移可能出现时滞现象，且工程结构的自振周期与出现结构最大位移的 时间密切相关，特别在长周期结构中，位移主要受瞬态振动的控制，因而传统结构动力学通常不考虑瞬态振动的结 论不适合于长周期结构。本文通过小波分解、振幅调整、线性迭加三步骤实现了地震动瞬态反应与稳态反应的分离， 通过小波分量瞬态反应与反应谱研究，证实了长周期结构的最大位移不仅可能发生在共振情况下，也可能发生在外 载激励已经消失，但结构的瞬态振动仍有较大余幅的情况下。瞬态振动对长周期结构位移反应的影响与持时呈密切 的关系。 关键词：有限持时，长周期结构，动力响应，小波变换，瞬态反应 Effects of Finite Duration Earthquake on Long Period Structural Dynamic Response Abstract: It is indicated from the finite duration instance that time delay is possible to happen in structural maximum displacement. Structural natural period is closely connected with the time of maximum displacement. Specially, in long period structures, displacement is mainly controlled by transient vibration so that transient vibration could not be ignored, which differ from the traditional structural dynamics. In this paper, earthquake transient response is got by wavelet transform, amplitude adjustment and linear superposition. It is approved that maximum displacement of a long period structure will occur both in sympathetic vibration and in external load is stopped but structural transient vibration is still has great amplitude. Furthermore, as for long period structures, there is close relationship between transient vibration and duration. Key words: fini