Hi! , Silvia

I am beginner in opensees and need your help with regard to modeling steel damper as bilinear or tri linear force-deformation relation.

My aim to model steel damper in order to make the comparison of hysteretic curve which obtained from experimental test with simplified model. In bilinear model the input data is elastic stiffness, yield force or yield displacement and post yield stiffness ratio , while the loads is cyclic increasing displacement. for example 0 1 0 -1 0 2 0 -2 0 4 0 -4 ....so on. After that I want to calculate the area under hysteretic curve as hysteretic energy. What type element should be used if the material data is not stress-strain but force-displacement. your help is highly appreciated.

Regards

Daniel