Nonlinear elastic NDmaterial

[Aliyaghfoori]

Dear STKO Team,
I hope this message finds you well.
I am currently working on a geotechnical simulation in which I need to model the nonlinear elastic behaviour of bedrock. My goal is to represent a material that:
• Exhibits a nonlinear stress-strain relationship
• Remains fully elastic and reversible.
Which nDMaterial model do you recommend for modelling such a nonlinear elastic material?

Thanks.

[STKO Team]

As far as I know, there is no specific nonlinear elastic NDMaterial in OpenSees.
However, I remember (looking into the source code of PDMY02 material) that there is a function that scales the elastic moduli as a function of the stress state, and is called only when the material is updated to plastic.
I've never tested it.
But try to use that material, switch it to plastic, but use a quite high strength so that it never really exhibits plasticity. Not sure it will work as you expect but you can give it a try

[Aliyaghfoori]

Thank you for your response. I will do this task and, if you’d like, I can share the result in the forum.

[STKO Team]

Ok