Concrete Drucker-Prager Softening Material Model
for my master thesis I simulate a Timber-Concrete-Composite Beam. Therefore, I should consider cracks in the tension zone of the concrete slab. First idea was to use a concrete Drucker-Prager softening material model (see picture 1).
I used a patch-test to verify the material model. Unfortunatly, the stress-strain curves under compression and tension are not as I imagined (see picture 2). I attached self-drawn stress-strain curves to show you how they should look like (see picture 3).
Furthermore, there are Solver-Pivot Warnings during the patch-tests, howerver, the calculation works. But for a simply supported beam the calculation doesn't converge. (I have already defined substeps.)
Can someone help me please? Did I define the Drucker-Prager softening wrong?
Thanks in advance!