nYou don't need to add an APDL command object in Mechanical to call out CONTA172. That is automatically used when you define bonded contact.nIt looks like you have setup the other details under contact in order to do debonding.nThe mesh you are using is way too coarse. All the examples I have seen have a much finer mesh.nIn all the examples I have seen of debonding, the two materials are touching and do not have a gap like you show. I don't know if a gap will work.nAll the examples I have seen include an initial crack in the model. In other words, if the two plates are 10 mm long, there could be a 1 mm unbonded length and the bond between the plates is only 9 mm long. That means you have to split the face on each plate to create two faces. There may be 100 elements along the plate. If you pull up on the edge of the plate, there are 10 elements being flexed before the first contact bond.nTo make a bilinear material, use Workbench, double click on the Engineering Data cell to open that tab. In the Toolbox, expand the Plasticity category. Drag the Bilinear Isotropic Hardening model onto your material and fill out the Yield Strength and Tangent Modulus. If you don't know the Tangent Modulus, use 0.n