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.