How the dashpots affect the Damping & Stiffness matrix?

xieyazhou · Post by **xieyazhou** » Sat May 03, 2014 5:53 pm

Hi Everyone!

I am using UiSimCor to connect OpenSees for my hybrid simulations for a bridge including SSI. At each time step UiSimCor just read the restoring force from OpenSees and input the forces to my condensed hybrid model. And I have to compose a damping matrix for my UiSimCor model separately, for the structural damping part I use the same Rayleigh Damping coefficients and it turns out my UiSimCor model has the same response comparing to the whole OpenSees Model.

While since I have to use several linear dashpots to model the SSI effects. I do not know how these dashpots affect the damping matrix and stiffness matrix in OpenSees. From common sense say if I add a dashpot with 'c = 10e5' between node 100 and 101, I thought the damping matrix will be changed to:
C new (DOF of node 100) = C old (DOF of node 100) + 10e5; C new (DOF of node 101) = C old (DOF of node 101) + 10e5; and the stiffness matrix will not change.

Is this correct? I changed my code in this way it seems the responses are different.

Thanks for any helps.
Tim