Viscoelastic damper curve type

03-Analytical/modelling capabilities
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ali_hssn
Posts: 10
Joined: 24 May 2015, 11:39

Viscoelastic damper curve type

Post by ali_hssn »

Comparing the VISCOELASTIC damper response curve in the literature and those available in the link elements in SeismoStruct, it seems that none is suitable for viscoelastic modeling.
Does anybody have suggestions for this matter?
Which link element is the most similar to the real viscoelastic damper response curve?
Thanks for your assistance.
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z.gronti
Posts: 824
Joined: 16 Oct 2013, 08:14

Re: Viscoelastic damper curve type

Post by z.gronti »

Dear ali_hssn,

Is the vsc_dmp response curve suitable for your model?
Zoi Gronti
Seismosoft Srl.
ali_hssn
Posts: 10
Joined: 24 May 2015, 11:39

Re: Viscoelastic damper curve type

Post by ali_hssn »

Dear Zoi,

Thanks for your reply.
Unfortunately, it is not. vsc_dmp represents VISCOUS damper but not VISCOELASTIC damper.

Ali
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ruipinho
Posts: 165
Joined: 07 Dec 2013, 14:37

Re: Viscoelastic damper curve type

Post by ruipinho »

Dear ali_hssn,

While there is indeed not a dedicated viscoeleastic damper element in SeismoStruct's elements library, can you not follow one of the two following alternative modelling strategies:

- introduce link+dashpot elements in parallel in order to directly reproduce the velocity-dependent behaviour of a viscoelastic damper,
or
- associate to a link element a response curve (e.g. 'smooth', 'Bouc_wen', etc) that has been appropriately calibrated to provide an hysteretic response that, even if not explicitly velocity-dependent, will be similar to that generated by the viscoelastic damper that you are trying to model?

Best regards,

Rui Pinho
ali_hssn
Posts: 10
Joined: 24 May 2015, 11:39

Re: Viscoelastic damper curve type

Post by ali_hssn »

Dear Rui,

Thank you for your reply.
I think the second option you mentioned fits my desires. I like to have a non-velocity-dependent viscoelastic damper. So, I have no issue with regard to that.
I also thought about the Bouc_Wen response curve, but I was not sure if it was the best. Now, having your comment, I think I can try the Bouc_Wen curve.

Best,
Ali
ali_hssn
Posts: 10
Joined: 24 May 2015, 11:39

Re: Viscoelastic damper curve type

Post by ali_hssn »

Hi,

In the case of having a link element (zero-length) which suppose to act as a damper (linear or bilinear). If we introduce damping to the element, how does this damping affect the link element? Is it parallel with stiffness or series? How can we model a Kelvin damper?

Thanks
Ali
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ruipinho
Posts: 165
Joined: 07 Dec 2013, 14:37

Re: Viscoelastic damper curve type

Post by ruipinho »

Hi Ali,

I carried out a search on the term "Kelvin" in SeismoStruct User Manual and Help System, and found the following:
The dashpt element may be employed whenever the need arises for the introduction of a Maxwell model (i.e. series coupling of damping and stiffness), by placing in series a link and a dashpt element. For a Kelvin-Voigt model (i.e. parallel coupling of damping and stiffness), one may again make use of a link element, this time placed in parallel with a dashpt, though in these cases it may result easier to simply assign directly to the link element a given viscous damping value.
So, the answer to your question is: parallel.

Regards,

Rui
ali_hssn
Posts: 10
Joined: 24 May 2015, 11:39

Re: Viscoelastic damper curve type

Post by ali_hssn »

Dear Rui,

Thank you for your helpful reply and my apology for not reading the manual properly.

Best,
Ali
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