General Mechanical

General Mechanical

Creep integration algorithm did not converge for element

    • HBaji
      Subscriber

      Hi,


      I have a simple model with a single element to test plasticity and creep of PLANE182 elements to be used for concrete. For plasticity Menetrey-Willam material is used and for creep implicit model 6 is used. The model runs fine for plasticity and creep if they are not run simultaneously.


      Once they are combined the warning " Creep integration algorithm did not converge for element" and the model does not run. The input file is as follows,


       


      FINISH


      /CLEAR


      /TITLE, Menetary-Willam Test With Creep


       


      Fc = 30.0


      ft = 3.0


      Ec = 30000


      Nuc = 0.20


      ec0 = 0.002


      etu = 0.002


       


      !......................................................................................................................................................................................................


      ! Model Geometry


      /PREP7


       


      ! ELASTIC CONSTANTS


      MP, EX, 1, Ec 


      MP, NUXY, 1, Nuc


       


       


      TB, CREEP, 1, 1, 4, 6


      TBDATA, 1, 0.1058*2.35/Ec, 1, -0.8575, 0


       


      ! Base Menetrey-Willam concrete 


      Rc = Fc         ! uniaxial compressive strength


      Rt = ft         ! uniaxial tensile strength


      Rb = 1.20*Fc    ! biaxial compressive strength


       


      psi = 33        ! dilatancy angle


       


      ! Linear hardening softening 


      omega_ci = 0.33


      omega_cr = 0.20


      kappa_cm = ec0 - Fc/Ec


      kappa_cr = 0.008 - omega_cr*Fc/Ec


       


      omega_tr = 0.20


      kappa_tr = (1.0 - omega_tr)*etu


       


      TB,CONCRETE,1, , , MW


      TBDATA, 1, Rc, Rt, Rb


       


      TB,CONCRETE,1, , , DILA


      TBDATA, 1, psi


       


      TB,CONCRETE, 1, , , HSD6


      TBDATA, 1, kappa_cm, kappa_cr, omega_ci, omega_cr, kappa_tr, omega_tr


       


      ET, 1, PLANE182


      KEYOPT, 1, 1, 0


      KEYOPT, 1, 3, 0


      KEYOPT, 1, 6, 0


       


      ! Nodes


      N, 1, 0, 0, 0


      N, 2, 1, 0, 0


      N, 3, 1, 1, 0


      N, 4, 0, 1, 0


       


      ! Concrete Element Generation


      TYPE, 1


      MAT, 1


       


      EN, 1, 1, 2, 3, 4


       


      ! Support


      D, 1, UX, 0


      D, 1, UY, 0


      D, 4, UX, 0


       


      FINISH


       


      !....................................................................................................................................................


      /SOLU


       


      SOLCONTROL, ON


      NLGEOM, ON


       


      RATE, OFF


       


      TIME, 1e-8


      F, 2, FX, -3/2


      F, 3, FX, -3/2


      SOLVE


       


      NSUBST, 100, 1000000, 100


      NEQIT, 100


      OUTRES, ALL, ALL


       


      RATE, ON


       


      TIME, 5


      SOLVE


       


      FINISH


       


      I am not even sure if ANSYS can combine the Menetrey-Willam plasticity and creep.


       


      Any help is appreciated.


       

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