General Mechanical

General Mechanical

classic Drucker-Prager material model in apdl

    • user8179
      Subscriber
      Dear all,nI have used classic Drucker-Prager material model in my 2D (I am using Plane183 {Palne strain} for Ballast,sub ballast and soil/ Plane183{Plane stress with Thk for railsleeper, rail and railpad})nI have defined both linear elastic and inelastic (non-metal plasticity>drucker-prager) behaviors, but the simulation terminates due to a large number of warnings regarding the YIELD FUNCTION in Extended Drucker-Prager (EDP) model. See the warning message:nEDP plasticity: Yield Function Not Defined for element 909 and materials (Ballast, SubBallast,Soil). nnI cannot find any option in Material Models Window to define yield function. There is not also EDP model there. Is it accessible only by scripts?nWhere I have done wrong? nnIs there any other alternatives for Drucker prager model in Workbench and apdl ?n nKind regards,nNaveen Maddela.n
    • John Doyle
      Ansys Employee
      It seems like you are trying to use the old TB,dc, command for classic Drucker Prager with the newer 18x elements. If that is the case, try switching to TB,CONCR,1,,,DP. Refer to Section 4.9.5.2 of the Material Reference Guide for details on proper TBDATA input with this format. You will not be able to define or list this material data in the MAPDL GUI. Alternatively, if you want to keep the old TB,dc, format, you could try switching your element type to the old PLANE42 or 82. In either case, you should not be getting any warnings or error messages about EDP yield surface when using classic Drucker Prager. That sounds like a bug.n
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