入力加速度波形の初期位相特性が履歴型非線形系の非対称応答に及ぼす影響

抄録

The aim of this paper is to investigate the influence of the initial phase distribution of the input acceleration wave on the asymmetric response of hysteretic nonlinear systems. In order to attain the aim, stochastic responses of SDOF bilinear hysteretic systems subjected to some kinds of simulated acceleration waves, which have specified initial phase distributions, were calculated. Through the examination of the response characteristics with respect to maximum and minimum values of the relative displacement and velocity, the following conclusions were obtained in connection with hysteretic nonlinear systems with plastic flow. 1) Remarkable asymmetry of the relative displacement response occures according to the initial phase distribution of the input acceleration wave. 2) Uniform distribution of the initial phase of the input acceleration wave playes an important role to maintain symmetry of the relative displacement response. 3) Relative velocity response is not affected by the initial phase of the input acceleration wave so much as the relative displacement response. Effect of the initial phase distributin of the input acceleration wave on the linear system response was also investigated. When a frequency band, in which phase inclination is almost constant, exists near the natural frequency of the system, the degree of the effect depends on the frequency band width. In the case that such frequency band spreads widely, initial phase has a great influence on the relative displacement response of the linear system. The conclusions obtained in this paper indicate the necessity of the incorporation of the parameters prescribing Fourier phase spectrum of the input seismic wave into stochastic response analyses of structures.