{"id":179464,"date":"2023-08-25T12:16:29","date_gmt":"2023-08-25T12:16:29","guid":{"rendered":"\/knowledge\/forums\/topic\/my-structures-first-natural-frequency-is-slightly-less-than-the-starting-frequency-of-the-psd-spectrum-should-i-go-for-random-vibration-analysis\/"},"modified":"2023-08-25T12:16:29","modified_gmt":"2023-08-25T12:16:29","slug":"my-structures-first-natural-frequency-is-slightly-less-than-the-starting-frequency-of-the-psd-spectrum-should-i-go-for-random-vibration-analysis","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/my-structures-first-natural-frequency-is-slightly-less-than-the-starting-frequency-of-the-psd-spectrum-should-i-go-for-random-vibration-analysis\/","title":{"rendered":"My structure’s first natural frequency is slightly less than the starting frequency of the PSD spectrum. should i go for random vibration analysis?"},"content":{"rendered":"

My first fundamental frequency is 47 hz. and my PSD data end at 45 hz ..should i go for random vibration analysis..? As the 1st natural frequency is very close the one of the excitation frequency, dynamic magnification is expected. However, the amount of dynamic magnification depends on the damping and direction of excitation and mode shape. If the excitation direction is same as that of the mode shape, then there would be considerable magnification. So it recommended to do a PSD analysis. <\/p>\n

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