Uniaxial Material: Bilinear stress-strain & Initial strain

[nbazaraa]

Dears,

I need to model a uniaxial material with bilinear stress-strain such as Steel01 or Steel02 , but with some initial strain to model post-tensioning bar modeled as truss element in 2D plane analysis, any material suggestion please ?

I tried to repalce the initial strain with a constantLoad (axial load) and used Steel01 but I still not satisfied with the results???

[fmk]

have you tried the fllowing material?

http://opensees.berkeley.edu/wiki/index ... n_Material