How to create Nonlinear SDOF Model (Single Dgree Of Freedom)

[omidgahremani]

Dear all
How can I create a nonlinear SDOF model for using in nonlinear response history analysis?
and which parameters should I have to create this model?
I'll be very grateful for any instruction or script that could help.
P.S : my model has viscous damping and it need to be applied in modeling too .

[fmk]

a model using either a truss or zero-length element with a nonlinear material (any unixialMaterial but elastic)

look at the sdofTransient.tcl file in the verification suite. it's more complicated than you need. but the last little snippet of code runs some analysis of a record for different periods and damping ratios and compares with some examples in prof. Chopras book.

http://opensees.berkeley.edu/WebSVN/lis ... ication%2F

[omidgahremani]

Dear fmk,
Thank you for your help
best regards,
gahremani