Velocity Response Spectra

02-Analytical capabilities
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nubufi
Posts: 1
Joined: 15 Apr 2020, 17:24

Velocity Response Spectra

Post by nubufi »

Hello I have v5.1 of seismosignal. I used both python and matlab to calculate response spectra for acceleration, velocity and displacement. My codes are giving almost exactly the same results for acceleration and displacement. But I have two times bigger values for velocity than seismosignal. The formula is ;
w = 2*pi / periyod
velocity = displacement * w
acceleration = displacement * w^2
Since I'm calculation displacement and acceleration correctly, I can't be calculating velocity wrong. Do you have any idea what is going on ?
huffte
Posts: 978
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
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Re: Velocity Response Spectra

Post by huffte »

Hi nubufi. Note that your equations are for pseudo-spectral-velocity (PSV) and pseudo-spectral-acceleration (PSA).

SeismoSignal reports both spectral-velocity (SV) and pseudo-spectral-velocity. While typically quite close over a wide period range, they are different and can be significantly different.

Make certain you are comparing apples to apples.

In SeismoSignal 2020, I loaded an accelerogram and manually calculated PSV from SD using the equation you mention. I then compared that to SeismoSignal reported PSV and they match.
Tim Huff
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