SAP 2000v14

[idns80]

Hi to everyone.

I have made a model of a three storey plane frame with viscoelastic dampers and plastic hinges by using Link elements which is subjected to earthquake loading and i am particularly interested in finding the energy which is absorbeb by the dampers and the hinges.I used the multilinear plastic type of Link element for modelling hinges and damper type for modelling damper. I solved the frame with non linear time history by direct integration but the result table with the energy components has only zero values. It is very strange because when i plot axial force-deformation in both the hinges and the dampers i get hysteretical loops. I also tried the modal non linear time history method and although i get values in the energy table the value of energy dissipated by hysteretic links is 0 and the sum of the other types of energy are about 15% more than the input energy.But apart from that is the modal non linear time history method suitable for the modelling of plastic hinges? Because it is supposed to be most suited for structures with a limited number of non linear elements. Any suggestions? Thanks

 

[Deddolo]

I don't if it's still useful right now, but I had the same problem.
My guess has been that Multilinear plastic links don't generate any energy output...so dumb tho. If your force-deformation behavior is similar has a kinetic hardening behavior with no softening, try using the WEN PLASTICITY for the NL Link, it gives energy output as "Link Hysteretic Energy". Although you still need to use the modal integration, I don't know if it's possible to obtain energies with direct integration, I'm trying to do that but no success.