Hi everyone!
I am starting to using the STKO software (literally I started yesterday) and I have a question: I want to use the ASDConcrete3D with a Preset Concrete (4P) for the constitutives shapes in tension and compresion, but I am not sure if the value that I input for fracture energy is the original fracture energy (with N/mm units for example) or is the original fracture energy divided by the characteristic length of the finite elements (with N/mm2 units in this case)? I have this issue because in other materials -like DamageTC3D or the User-Defined preset- it is explicit the autoRegularization option.
Also, in the case that the value that I have to input is the "original" fracture energy (in N/mm units), the software automatically recognizes the characteristic lenght of the mesh in the model? How does it work?
Thanks in advance!
Fracture Energy in ASDConcrete3D
Re: Fracture Energy in ASDConcrete3D
When you use the presets, the fracture energy is always assumed in F/L, thus the automatic regularization is ON by default.
If instead you choose "User-Defined", you define the stress-strain curve, thus the fracture energy is not directly inputted by the user, but it's the area under your user stress-strain curve. In this case STKO asks you if you want to do the auto-regularization, and if yes, you have to define the reference size of the specimen from which you obtained that stress-strain curve.
In both cases, OpenSees will recognize, for each element, the element characteristic length, and will do the regularization
If instead you choose "User-Defined", you define the stress-strain curve, thus the fracture energy is not directly inputted by the user, but it's the area under your user stress-strain curve. In this case STKO asks you if you want to do the auto-regularization, and if yes, you have to define the reference size of the specimen from which you obtained that stress-strain curve.
In both cases, OpenSees will recognize, for each element, the element characteristic length, and will do the regularization