subsection Material model
  set Model name = drucker prager

  subsection Drucker Prager
    set Reference density = 2800

    subsection Viscosity
      set Minimum viscosity = 1e19
      set Maximum viscosity = 1e25
      set Reference strain rate = 1e-20
      set Angle internal friction = 30
      set Cohesion = 20e6
    end
  end
end
