I wrote a subroutine UDMGINI to define a damage initiation criterion, but I found that the variables of stress were very strange. I kept track of stress (NTENS) using the state variables STATEV, and I was surprised to find that the STATEV didn't correspond to the output variables S (the 6 composants respectively). Has someone ever encountered this problem? Thank you very much. If someone wants to communicate with me about the XFEM in Abaqus, I will be very happy.
Thank you. In fact, I have read this document, there is nothing different with the documentation Abaqus. My problem concerns the stress passage in local coordinates from Abaqus calculation serveur to the subroutine UDMGINI, because I used the material orientation.
Best regards,
Lv ZHAO
Hi,
I'm facing the following problem and I hope you can help me with that one. The goal is to use an UMAT with XFEM crack initiation/growth in the same model.
This, I think, is the crucial part of the .inp-file:
...
*Enrichment, name=Crack-1, type=PROPAGATION CRACK, elset=_PickedSet4
*End Assembly
**
** MATERIALS
**
*Material, name=GenericMaterial
*User Material, constants=x
**x material constants cut out**
*Depvar
x,
*Damage Initiation, criterion=MAXPS, tolerance=0.1
2.,
*Damage Evolution, type=DISPLACEMENT
1e-09,
** INTERACTION PROPERTIES
**
*SURFACE INTERACTION, name=Crack-1
*SURFACE BEHAVIOR, PRESSURE-OVERCLOSURE=LINEAR
1
**
**STEP
...
Following error in the .dat-file occurs:
*elementoutput, elset=ASSEMBLY_ALL_EL, directions=YES
*elementoutput, elset=ASSEMBLY_ALL_EL, directions=YES
*elementoutput, elset=ASSEMBLY_ALL_EL, directions=YES
***ERROR: THE PENALTY STIFFNESS HAS TO BE PROVIDED BY USING *SURFACE
BEHAVIOR,PRESSURE-OVERCLOSURE=LINEAR OR *SURFACE BEHAVIOR,AUGMENTED
LAGRANGE WHEN USER MATERIAL IS USED FOR A CRACK PROPAGATION ANALYSIS
WITH XFEM
I also tried augmented lagrange for the surface behavior - with the same effect.
I'd greatly appreciate any advice
Thank you
Thanks for your prompt reply. I have tried all these including Hard for PRESSURE-OVERCLOSURE but the error is same. Do you have any idea how to get rid of it? FF
Hello,
I'm sorry that I haven't seen your input file untill un few minites ago. I just looked inside, you have frogotten in fact to give the contact property to your enrichment assignment. In the line "*Enrichment, name=Crack-1, type=PROPAGATION CRACK, elset=_PickedSet24", you should add " interaction=IntProp-1".
Try this, your problem would be probably solved.
Best regards,
Lv ZHAO
Dear Zhao thansk for your reply. It worked. Thanks though for your answer.
Hi Dear Farukh Farukh
I am modeling crack initiation and propagation using x-fem. I have used subroutine umat for modeling isotropic plasticity behavior of my material. but when i run the input file, i see this error:
"Analysis Input File Processor exited with an error"
The important part of input file is as follows:
*Material, name=Material-1
*User Material, constants=8
82000., 0.2,3500., 0.,3510., 0.1,3520., 0.5
*Depvar
13,
*Damage Initiation, criterion=MAXPS
30,
*Damage Evolution, type=DISPLACEMENT
1.,
I will be very thankful if you would please help
Hi
I am trying to model a chain under low cycle fatigue analysis with crack initiation and propagation. I have come across with the following error message:
***ERROR: THE PENALTY STIFFNESS HAS TO BE PROVIDED WHEN USING *SURFACE BEHAVIOR,PENALTY
I appreciate anyone's help to point out the potential sources of this error message. Thanks in advance.
Hasan
You should give contact property to your enrichment assignment. It will work fine.
Dear Zhao
have you solved this problem? i suffer the same problem
best regards
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