狭帯域の位相差分特性を用いて作成された狭帯域波を受ける1質点系の確率統計的応答について

抄録

In this study standard deviation of responses of a SDOF system subjected to narrow band waves is obtained by means of the Fokker-Plank equation. Envelope shapes of these narrow band waves can be characterized by the individual Gaussian phase difference distribution. The average of phase differences corresponds to the predominant time of the wave and the standard deviation corresponds to the duration of the strong portion. When these parameters i. e., the average and the standard deviation of phase differences, are appropriately determined, various narrow band waves with specified nonstationary power spectral characteristics can be generated. Then these waves are regarded as a model response of a surface layer with natural frequency f_0 and damping h_g subjected to white-noise with spectral level S_0 and operating time T_w at the seismic base. Parameters hg, S_0 and T_w are determined so that the standard deviation of each narrow band wave coincides with that of the response of surface layer. Finally stochastic responses of a SDOF nonlinear system are obtained by applying this model and are compared with simulated results which are computed as the response due to narrow band waves in time domain.