Modelling Rock using Drucker Prager Model
Modelling Rock using Drucker Prager Model
(OP)
Hi,
Does anyone have tips on modelling rock in ANSYS (structural analysis)? From my research so far, it seems I have to use an extended Drucker Prager model. I am having difficulty in understanding what the basic difference is between using a Drucker Prager model & the standard method of analysing metals? Can someone please explain this concept?
Thanks,
Mike
Does anyone have tips on modelling rock in ANSYS (structural analysis)? From my research so far, it seems I have to use an extended Drucker Prager model. I am having difficulty in understanding what the basic difference is between using a Drucker Prager model & the standard method of analysing metals? Can someone please explain this concept?
Thanks,
Mike





RE: Modelling Rock using Drucker Prager Model
Rock and similar materials respond differently in tension and compression (i.e., they can take more load in compressive stress states). Drucker-Prager is similar to von Mises but adds some dependence on the hydrostatic part of the stress.
RE: Modelling Rock using Drucker Prager Model
So if we have two identical geometries and one of them has a Drucker Prager material model applied to it, the values of stress and deformation will be different because of a change in the yield point due to the hydrostatic part of stress?
RE: Modelling Rock using Drucker Prager Model
RE: Modelling Rock using Drucker Prager Model
Then how does FEA take the Drucker Prager material non-linearity into account while solving the model?
RE: Modelling Rock using Drucker Prager Model
vtmike, I think all that Terio was stating was that 1 square inch of ANY material subjected to 1000 lbf load will have a compressive stress of 1000 psi for equilibrium (assuming the material can withstand that stress). This is independent of material properties.
However, deformation is of course dependent on material properties.
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RE: Modelling Rock using Drucker Prager Model
RE: Modelling Rock using Drucker Prager Model
As the collegues pointed out, unlike Von Mises or Tresca, it is a pressure-dependent criterion. Rocks, concrete, polymers or foams are pressure-dependent materials with differente behaviour in tension and compression, metals are independent of (spherical or hydrostatic) pressure.
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RE: Modelling Rock using Drucker Prager Model
I desparately need to do an analysis which is basically defining a triaxial test on a rock and applying the Drucker-Prager model.
Do you have any D-P UMAT availabe to share?
Thanks a lot for your help in advance