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alb2
Posts: 47
Registered: ‎05-14-2012
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responce spectrum

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12-05-2012 07:16 AM

Hello,

since I cant find any tutorial for spectrum analysis for RSA, i am trying to slove a staad example in RSA.

the model is attached, but i am getting confused with modal analysis and the spectral analysis., cant get the same results as in the example.

 

Can you please explain how to apply correctly the modal analysis for the load case 2, and the spectral anlysis for the given requirement : spectum CQC X 1 ACC DAMP 0.05

 

Thank you

 

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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: responce spectrum

12-05-2012 07:21 AM in reply to: alb2

Send us staad file also



Rafal Gaweda
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Active Contributor
alb2
Posts: 47
Registered: ‎05-14-2012

Re: responce spectrum

12-05-2012 07:26 AM in reply to: Rafal.Gaweda

Unfortunately I dont have the staad file, I was verifying the example into RSA from the data in pdf file. Sorry

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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: responce spectrum

12-06-2012 01:07 AM in reply to: alb2

we see different results (natural freq in modal) and even in static case 1 – Fx reactions , Fz are correct

We guess that sectional properties can be a little bit different (A Ix Iy Iz) for these sections.



Rafal Gaweda
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Active Contributor
alb2
Posts: 47
Registered: ‎05-14-2012

Re: response spectrum

12-06-2012 01:19 AM in reply to: Rafal.Gaweda

Can you please send me the model, I want to see how to apply correctly the modal analysis and the spectral one.

And also, I don't know how to decide regarding the load to mass convertion, add mass to dynamic load or modal case, which direction and coeff. to chose.

Is this specified in any code in respect of the structure, or is a decision that the designer have to make?

 

Thanks

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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: responce spectrum

12-06-2012 03:59 AM in reply to: alb2

If we consider load case as loads for mases for mode \ spectral case it is enough to defined them as below, model case settings and load to mass conversion also.

 

modal.jpg



Rafal Gaweda
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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: responce spectrum

12-06-2012 04:01 AM in reply to: Rafal.Gaweda

Spectral case definition movie: http://screencast.com/t/upYuXbUiyiv

File attached



Rafal Gaweda
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Active Contributor
alb2
Posts: 47
Registered: ‎05-14-2012

Re: responce spectrum

12-06-2012 04:04 AM in reply to: Rafal.Gaweda

Thanks

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