Seismosoft | Earthquake Engineering Solutions

Hi I have Tried the SDOF system with 2 node at the same place and connecting them via MIMK bilin with one node restraint. The Cyclic load is imposed to the free node but the results are showing descrepency. I have tried the same structure using Opensees and those results are completely different

Obviously, the fact that you are getting different results with Opensees does not provide enough information.
The MIMK curve are checked rather well in SeismoStruct by a large number of users, hence we doubt if there is a problem with the curves.
Can it be that you are using different input parameters?
You could start with a simple model, gradually increasing the complexity and checking the results against Opensees.
Seismosoft Support

Actually the simplest model that can be used is made (2 node and one link under a simple cylcic loading)
I can provide you with my seismostruct file in case of necessity.

We meant a model with simple input parameters for the MIMK curve. Then you could gradually increase the complexity in both model and see what gives the differences.
Seismosoft Support