I am modelling RC beams reinforced with FRP ( GFRP,CFRP,BFRP) rebars, I have found that the best definition of interaction is, to use Cohesive behavior (it is better than Cohesive element due to the negligible interaction thickness).
My questions is ;
How can I get Cohesive behavior, damage initiation and damage evolution parameters; Cohesive behavior=(Knn,Kss,Ktt)
damage initiation =Normal only,Shear-1 only,Shear-2 Only
damage evolution=Total/Plastic Displacement
Thanks
Parameters of the stiffness matrix (Knn, Ktt and Kss) are correlated to the contribution of the FRP and the surrounding bulk materials at the response of the interface zone. Assuming that an effective thickness of these materials contributes to the local bond-slip response in a way such as parallel springs then one can calculate these stiffness parameters. However, practically is a challenge to obtain these information through macro-scale experimental tests. I suggest that you perform an inverse analysis using FEM and take the loaded-end and free-end slip of the FRP obtained from experimental tests as the references for the model calibration. Depending on the orientation of principal stresses, even in a 3D model, you might be able to assign large values to the normal direction and then assuming both transverse directions has the same bond-slip response.
Studies of very pure materials (tool - electrolytic copper; workpiece - nickel or aluminum, dielectric - n-dodecane) have shown that no other elements on the machined surface could be detected. With optimum selection of process parameters there is only a small portion of molten and modified material structure on the surface. The largest removal is effected by evaporation.
When machining far away from the optimal process parameters occurs high process instability, eg arcs, which then lead to significantly lower fused areas.
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