post-peak behavior of steel-concrete structure

[1908fem]

Hello,

trying to model a steel concrete filled tube under compression. I have used CDP with damage using the dynamic explicit solver.

I use a displacement BC to apply the load. Despite the results look good until the peak load is reached after that there is no descending branch in my force-displacement curve.

Any ideas why that is happening?

 

[Mustaine3]

This only possible with a material damage or a structural collapse (buckling).

Material damage would be usually Damage Initiation and Damage Evolution. See manuals.

 

[bkal]

This is just a wild guess (I am not an expert on concrete models in ABAQUS) - is your concrete in essentially confined conditions (i.e. being under triaxial compression)? If so, how does the concrete model deal with that? What does the force-displacement curve look like - can you post it? Have you tried to run the model without the steel tube?