I am modelling an interfacial zone by cohesive elements in ABAQUS. In order to conduct a parametric study, I need to change thickness of the cohesive elements in a range (assume in the range of 0 to 0.8 mm). In a manual, it has been written that when a unit thickness is specified during defining section in the property module , penalty stiffness is the same as the elastic modulus and thickness of the layer is kind of ignored.
Herein, there are two questions;
1- Is it rational to use non-zero thickness cohesive elements at all (non-zero thickness in the model geometry and unit thickness in the cohesive section)?
2- How the penalty stiffness should be defined for the model with zero thickness up to that with 0.8 mm?
You can do either, if you model the actual thickness of the cohesive elements, then you can apply the young modulus basically. If you model it with 0 thickness, or even don't create elements just define an interaction, then what you can input basically is a E/delta so modulus over the desired thickness.
If I remember correctly, there are some example problems where you can see how this works, it might be worth going through that part of the manual.
Best regards,
David
I believe the penalty stiffness (kn) is the ratio between normal traction and the normal initial separation ~ kn=tn/uno. You can find these values for the respective materials in the literature.
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