## viscous and viscoelastic dampers

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

### viscous and viscoelastic dampers

Dear Seismosoft team

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

### Re: viscous and viscoelastic dampers

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

### Re: viscous and viscoelastic dampers

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

### Re: viscous and viscoelastic dampers

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

### Re: viscous and viscoelastic dampers

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.

Best regards,
seismosoft
Posts: 824
Joined: 06 Jul 2007, 04:55

### Re: viscous and viscoelastic dampers

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

### Re: viscous and viscoelastic dampers

Hi Seismosoft

Thank you so much.
farid
Posts: 5
Joined: 26 Dec 2017, 12:12

### Re: viscous and viscoelastic dampers

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

Thanks for this valuable information.