Fundamental principles from structural dynamics,random theory and perturbation methods are adopted to develop a new response spectrum combination rule for the seismic analysis of non-classically damped systems,such as...Fundamental principles from structural dynamics,random theory and perturbation methods are adopted to develop a new response spectrum combination rule for the seismic analysis of non-classically damped systems,such as structure-damper systems. The approach,which is named the perturbation spectrum method,can provide a more accurate evaluation of a non-classically damped system's mean peak response in terms of the ground response spectrum. To account for the effect of non-classical damping,all elements are included in the proposed method for seismic analysis of structure,which is usually ap-proximated by ignoring the off-diagonal elements of the modal damping matrix. Moreover,as has been adopted in the traditional Complete Quadratic Combination (CQC) method,the white noise model is also used to simplify the expressions of perturbation correlation coefficients. Finally,numerical work is performed to examine the accuracy of the proposed method by comparing the approximate results with exact ones and to demonstrate the importance of the neglected off-diagonal elements of the modal damping matrix. In the examined cases,the proposed method shows good agreement with direct time-history integration. Also,the perturbation spectrum method leads to a more efficient and economical calculation by avoiding the integral and complex operation.展开更多
The multiple quantum process, in which n quanta of energy ω0/n are absorbed or emitted between a pair of adjacent levels spaced out by ω0, is called subharmonie resonance （SHR）. There is no real intermediate level...The multiple quantum process, in which n quanta of energy ω0/n are absorbed or emitted between a pair of adjacent levels spaced out by ω0, is called subharmonie resonance （SHR）. There is no real intermediate level between the level pair. The transition between the two levels is generally allowed and it is directly observable under the pulsed excitation. The excitation will be very inefficient since the irradiation frequency is far away from, the resonance, so to deal with it, a higher order perturbation is needed.展开更多
基金Project supported by the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0518)the Program of Introducing Talents of Discipline to Universities (No. B08014), China
文摘Fundamental principles from structural dynamics,random theory and perturbation methods are adopted to develop a new response spectrum combination rule for the seismic analysis of non-classically damped systems,such as structure-damper systems. The approach,which is named the perturbation spectrum method,can provide a more accurate evaluation of a non-classically damped system's mean peak response in terms of the ground response spectrum. To account for the effect of non-classical damping,all elements are included in the proposed method for seismic analysis of structure,which is usually ap-proximated by ignoring the off-diagonal elements of the modal damping matrix. Moreover,as has been adopted in the traditional Complete Quadratic Combination (CQC) method,the white noise model is also used to simplify the expressions of perturbation correlation coefficients. Finally,numerical work is performed to examine the accuracy of the proposed method by comparing the approximate results with exact ones and to demonstrate the importance of the neglected off-diagonal elements of the modal damping matrix. In the examined cases,the proposed method shows good agreement with direct time-history integration. Also,the perturbation spectrum method leads to a more efficient and economical calculation by avoiding the integral and complex operation.
文摘The multiple quantum process, in which n quanta of energy ω0/n are absorbed or emitted between a pair of adjacent levels spaced out by ω0, is called subharmonie resonance （SHR）. There is no real intermediate level between the level pair. The transition between the two levels is generally allowed and it is directly observable under the pulsed excitation. The excitation will be very inefficient since the irradiation frequency is far away from, the resonance, so to deal with it, a higher order perturbation is needed.
