نوع مقاله : پژوهشی
نویسندگان
1 دانشکده ی فنی مهندسی، دانشگاه شهرکرد
2 دانشکده فنی مهندسی، دانشگاه شهرکرد
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
One of the methods of quake frequency investigation is the use of Fourier
series and power spectrum. In this paper, the frequency of the major structural
modalities in the earthquake is investigated using the power spectrum and the
frequency of the earthquake, which has the greatest effect on the structure
response. For this purpose, first, using the discrete wavelet theory, the
acceleration of the earthquake is filtered up to 5 steps. At each stage of the
filter, two waves of approximations and details are obtained. By analyzing the
frequency content of approximate waves and details using the power spectrum and the Fourier spectrum, it results that the frequency of the wave is closer to
the original wave of the earthquake. For convergence, the effect of frequency
due to different frequencies in approximate waves is considered by the
frequency effects of different frequencies in the main earthquake hypothesis
called the approximation of the approximate wave to the maximum acceleration of
the wave of the main earthquake. In order to verify the validity of the hypothesis, again, the Fourier spectrum and the power spectrum should be plotted for new approximation waves. After examining the frequency of the wave of approximations, it is concluded that the hypothesis works well. By studying
the frequency content of the new approximation wave, it follows that for
dynamic analysis, the frequency range of the power spectrum is more accurate
than the Fourier spectrum. For this reason, the power spectrum is used for
analytical calculations. Finally, with the investigations carried out in this paper, for the frequency domain analysis, the scalar approximation power spectrum is plotted. Then, several structures of the modal analysis and under the frequency spectrum of earthquake analysis are in the frequency domain. From the frequency response analysis curve and the results of the modal analysis, the frequency of the dominant mode of the structure is predicted. Using the wavelet transform, the number of accelerated earthquake mapping points reaches 1/32 But there was little mistake in estimating the prevailing frequency of the structure.
کلیدواژهها [English]
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