Envelope Shapes

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

Envelope Shapes

Post by zbadar »

Hello, I am interested to make artificial accelerograms using SeismoArtif (method 2 or 3) for use as input in dynamic analysis of large wind turbines combined with all other wind and operational loads. In SeismoArtif their is a big choice of Envelope Shapes but I am not completely sure which one should I employ? Necessary guidance is kindly requested.

thanks for a quick response in advance!
Best regards, Zia
huffte
Posts: 942
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
Contact:

Re: Envelope Shapes

Post by huffte »

Hi zbadar. I am far from being an expert on this, but I'll offer what I know.

The Jennings models were based on the following:
Model A - duration = 120 seconds, Rise time = 4 seconds, Level time = 35 seconds, intended to represent M8+ event close to the fault

Model B - duration = 50 seconds, Rise time = 4 seconds, Level time = 15 seconds, intended to represent a M7 event close to the fault

Model C - duration = 12 seconds, Rise time = 2 seconds, Level time = 4 seconds, intended to represent a M5.5-6.0 event in the epicentral region

Model D - duration = 10 seconds, Rise time = 2 seconds, Level time = 2.5 seconds, intended to represent a shallow M4.5-5.5 event close to the fault

The Saragoni and Hart model is the default in SeismoArtif. It would seem to be the best choice - but again, I am no expert. I'll reference a recent open access article, "Parameters Identification of Stochastic Nonstationary Process Used in Earthquake Modelling", by Giuseppe Carlo Marano, Mariantonietta Morga and Sara Sgobba. In the paper, they choose the Saragoni and Hart envelope function because it fit their real records better. They went on the modify the Saragoni and Hart model, but chose it as their basis.

The Liu model was based on the Parkfield earthquake, M5.6.

So, perhaps the Saragoni and Hart shape could be selected and you could tweak the parameters until you arrived at accelerograms which met some criteria for various intensity measures (PGV, significant duration, Arias intensity, cumulative absolute velocity, . . .). Of course, the choice of both intensity measures and their target values would have to be up to you.

And it might be wise to investigate some of the literature here for yourself as well.

Best of luck zbadar.

PS, SeismoSoft - the Hou, 1968 work referred to in the Help System seems to be missing form the bibliography.

Tim Huff
zbadar
Posts: 9
Joined: 18 Mar 2014, 04:57

Re: Envelope Shapes

Post by zbadar »

Hello huffte, Thank you very much for your fast and sufficiently detailed answer.
Post Reply

Return to “02-Analytical capabilities”