viscous and viscoelastic dampers

05-Future developments & requests
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mohammadzadeh
Posts: 13
Joined: 12 Apr 2014, 15:32

viscous and viscoelastic dampers

Post by mohammadzadeh » 25 Sep 2015, 09:29

Dear Seismosoft team

Thank you so much for very helpful your softwares.Please viscous and viscoelastic dampers models of hysteresis add to SeismoStruct(link element types part).

Best regards

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ruipinho
Posts: 158
Joined: 07 Dec 2013, 14:37

Re: viscous and viscoelastic dampers

Post by ruipinho » 28 Sep 2015, 12:43

Hi mohammadzadeh,

Do the current response curves available in SeismoStruct (e.g. bl_ kin, plst, etc.) not already allow you to reproduce typical viscous/viscoelastic hysteresis?

Best,

Rui

mohammadzadeh
Posts: 13
Joined: 12 Apr 2014, 15:32

Re: viscous and viscoelastic dampers

Post by mohammadzadeh » 30 Sep 2015, 08:19

Dear Rui
No, because viscous damper force is dependent on velocity.

F = CV^alpha
F = viscous damper force
C = damping constant
V = velocity
alpha = velocity exponent

Best regards,
Mohammadzadeh

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ruipinho
Posts: 158
Joined: 07 Dec 2013, 14:37

Re: viscous and viscoelastic dampers

Post by ruipinho » 04 Oct 2015, 10:49

Mohammadzadeh, hi.

Yes, sure, viscous dampers are obviously dependent on velocity, I appreciate that.

However, what typically happens is that their hysteretic response does not really changes that much within the velocity of ranges that one expects in an earthquake (peak values of 20-30 cm/s), this being the reason why often one pragmatically decides not to model such velocity dependence.

You may perhaps try to define hysteretic curves for your viscous dampers for different (realistic) values of velocity, run different structural analyses for each one of those hysteretic models, and see what sort of impact this has on your overall structural response?

You may also perhaps pay a look at some past posts on this topic (I found them by carrying out a search this Forum using the expression "damper velocity"):
- http://www.seismosoft.com/forum/viewtop ... 918&p=4641
- http://www.seismosoft.com/forum/viewtop ... 915&p=4640

Best,

Rui

mohammadzadeh
Posts: 13
Joined: 12 Apr 2014, 15:32

Re: viscous and viscoelastic dampers

Post by mohammadzadeh » 10 Oct 2015, 14:09

Dear Rui

Current response curves in SeismoStruct may use to define viscous dampers based on approximate simplified methods but for exact(and realstic) hysteretic curves need to velocity dependent hysteretic curves.

Damper exact response is needed in some research(not overall structural response).

I read past posts on this topic.The following video is an experimental study on a large-scale steel structure with nonlinear viscous dampers.

https://www.youtube.com/watch?v=1C8URWbteZM



Best regards,
Mohammadzadeh

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seismosoft
Posts: 592
Joined: 06 Jul 2007, 04:55

Re: viscous and viscoelastic dampers

Post by seismosoft » 14 Oct 2015, 14:57

Hi mohammadzadeh,

Thank you for your suggestion.
We will consider your request on viscous dampers for inclusion in a future release of SeismoStruct, but unfortunately not in v8, the development of which was completed just last month ( it wll be published in 2-3 months after all the checking and the translations have been carried out).

Regards,
Seismosoft Support

mohammadzadeh
Posts: 13
Joined: 12 Apr 2014, 15:32

Re: viscous and viscoelastic dampers

Post by mohammadzadeh » 14 Oct 2015, 18:35

Hi Seismosoft

Thank you so much.

farid
Posts: 5
Joined: 26 Dec 2017, 12:12

Re: viscous and viscoelastic dampers

Post by farid » 28 Apr 2018, 07:10

Dear members
could anybody send me a simple model of viscoelastic damper which modeled in seismostruct?
I think I have a problem in modeling of it.
thank you

Nayna
Posts: 2
Joined: 04 Apr 2019, 10:09
Contact:

Re: viscous and viscoelastic dampers

Post by Nayna » 04 Apr 2019, 10:13

Thanks for this valuable information.

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