Period range of response spectrum

02-Analytical capabilities
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zbadar
Posts: 9
Joined: 18 Mar 2014, 04:57

Period range of response spectrum

Post by zbadar »

Hello, in case of large wind turbines, the structural frequencies of as low as 0.1 to 10Hz are generally interesting with large slender components. For such a case what should be the range of chosen period of response spectrum in SeismoArtif to generate artificial accelogram? Also our load calculation softwares (e.g., Bladed / Flex5)usually uses time-step of 0.01sec. What time-step could we preferably use for artificially generated accelogram? Thank you in advance!!

P.S.: For your interest and information the rotational speed of rotor blades normally ranges between 7 to 18rpm for larger wind turbines.
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ruipinho
Posts: 165
Joined: 07 Dec 2013, 14:37

Re: Period range of response spectrum

Post by ruipinho »

Hi zbadar,

The period range that you indicate (from 0.1 to 10 seconds) is obviously extremely wide, and there is no single earthquake that will ever generate an accelerogram with such a wide-ranging frequency content (you can check this out yourself, by looking at the response spectra of records from different earthquakes, such as the ones installed by default with Seismosoft applications).

In any case, at this stage, and without entering into a more detailed and refined scrutiny of the work that you are trying to accomplish, I would suggest you to generate an accelerogram that is compatible throughout your entire range of interest with the response spectrum defined in the seismic code that you are using as a reference.

The above will be very conservative, since, as you know, code design spectra constitute an envelope of a number of possible "real" spectra, but, I repeat, without further scrutiny of your problem, this would be the approach that I would suggest.

Best,

Rui
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