Hello all, I’m modelling a rectangular CFST member under bending in Abaqus.
I’m assuming it’s best to use CDP for the concrete core. If that is the case, is it better to use unconfined concrete properties or a confined concrete model?
Any recommended papers or workflows for defining the CDP inputs for the CFST concrete?
Thanks!
Hi, I’m modeling a CFST member in Abaqus under bending. I used surface-to-surface contact between the inner steel tube and the outer concrete core. For the interface, I used hard contact in the normal direction and penalty friction in the tangential direction with a friction coefficient of 0.4, with separation allowed. In this case, the model gave about 200 kN peak load.
Then I replaced the concrete with steel properties as a sensitivity test, and the peak load still stayed around 200 kN, although the response curve was slightly different. But when I tied the core to the steel tube using tie constraints, the concrete-core model increased only slightly, while the steel-core model jumped to about 450 kN.
Does this mean the contact model is not engaging the core properly? What am I doing wrong, and how should the concrete-steel composite behavior in a CFST be modeled correctly?
Thanks!