bracing-friction damper system

[Salvatore Vera]

Hi
I'm trying to model bracing-friction damper system for seismic retrofitting an industrial bulding.
The system is very simple,it's comprised of one inner steel plate and two outer brass and steel plates.
Friction forces of the damper are produced in faying surfaces between brass and steel plates.
This system connects every beam to every top of the column of the frame.

Seismostruct proposes link elements to model energy dissipating devices.
I've modeled braces of the system with inelastic truss elements ( section and characteristics according with my system design)attached one end to the beam and the other one to the column.
I've located the link element with a Bilinear Kinematic Hardening curve and the end of truss element attached to the beam.

But in the post process step I've no useful results for link element (forces-deformations and hysteretic curves).
So:
1)what I've choiced it's a good way for modelling this damper-system in Seismostruct??

2) The energy dissipation I should have in my link elements (with the defined response curve) increase the damping of the global frame or i've to define expressly damping in the link element class properties??

[fbianchi]

Dear Salvatore,

1) Your choice to model the damper using a link element with associated an appropriate response curve seems correct. Have you checked that all the nodes are connected in the right way?
2) the nonlinear force-displacement response curve formulation used to characterise the response of link element implicitly includes the hysteretic damping. The non-hysteretic type of damping needs to be included separately (please refer to the help system for a detailed explanation on this matter)

Federica

[Salvatore Vera]

Yes I've checked up all the nodes of link elements and I've made mistakes in the elements connectivity, now they work correctly!


Another question, there's a way to counting the value of energy dissipation during the hysteretic cycles of link elements??

Thank you very much, Federica

[seismosoft]

Salvatore, hi.

As discussed in other posts in this Forum (search for "energy"), SeismoStruct does not automatically output dissipated energy values.

However, users should be able to readily obtain such quantities through the product/integral of the force-displacement response.

Seismosoft Support

[Salvatore Vera]

Yes, I know this way!
Thank you very much!!