Strange mesh from octree refinement

[charles]

Hi.
I have several questions about the octree refinement.

1. How does Texgen deal with the hanging nodes?

2. I added a 2D textile weave model using the default parameters.

octree0.png (171.85 KiB) Viewed 15593 times

I exported the octree refinement .inp to Abaqus using these parameters and output surfaces, refinement level: 3 and no smoothing.

octree1.png (12.1 KiB) Viewed 15593 times

Then I ran the simulation using the command line. It exited with errors. When I checked the .odb file, I got this very strange mesh. And there is a long list of distorted isoparametric elements in the .dat file. Did I do something wrong?

octree4.png (52.85 KiB) Viewed 15593 times

3. Is it possible to change the material properties and loading before outputting the octree mesh to Abaqus?

Many Thanks,
Charles

[charles]

Octree refinement output files can be downloaded from this link.
https://mega.nz/file/q1w0nSQR#KVkebJ6uP ... ZB4eGzJM_U

[louisepb]

Hi Charles,

Answering your questions in order:
1. The hanging nodes are constrained using multi-point constraints.
2. We thought that we'd sorted this issue out - we'll investigate and get back to you when we've found the problem.
3. You can change the material properties in the GUI using the Modeller Yarn and Matrix properties options described here: http://texgen.sourceforge.net/index.php ... Properties If you want to change the loading then you will need to change this in the Abaqus .inp file. There is no way to change this in TexGen.

Hope that helps,
Louise

[charles]

Hi Charles,

Answering your questions in order:
1. The hanging nodes are constrained using multi-point constraints.
2. We thought that we'd sorted this issue out - we'll investigate and get back to you when we've found the problem.
3. You can change the material properties in the GUI using the Modeller Yarn and Matrix properties options described here: http://texgen.sourceforge.net/index.php ... Properties If you want to change the loading then you will need to change this in the Abaqus .inp file. There is no way to change this in TexGen.

Hope that helps,
Louise

Hi Louise,

Thank you very much for your reply.

Many Thanks,
Charles

[louisepb]

Hi Charles,

I haven't uploaded it to Sourceforge yet, but there is a new release here https://github.com/louisepb/TexGen/releases/tag/v3.12.2 which should fix the bug in the octree meshing. Let me know if you still have problems.

Best wishes,
Louise

[charles]

Hi Charles,

I haven't uploaded it to Sourceforge yet, but there is a new release here https://github.com/louisepb/TexGen/releases/tag/v3.12.2 which should fix the bug in the octree meshing. Let me know if you still have problems.

Best wishes,
Louise

Hi Louise,

Thank you very much for fixing the bug. It works now. I have another question. How is cohesive contact defined? I checked the .inp file. I can see the surfaces of yarn and matrix are defined, but I can't find any relationship defined between these surfaces.

Many Thanks,
Charles

[georgespackman]

Hi Charles,

You need to define cohesive contact yourself in the .inp file. I have attached part of an example .inp file using the same octree mesh but configured so it produces regular rectangle voxels with yarn-matrix cohesive surface contact specified. I can't add the whole file as it is too large. You will need to make sure the cohesive interface properties are correct for your model. I have left in the step and output request information in case that's useful. You can see I'm using abaqus/explicit but it shouldn't make too much of a difference.

Code: Select all

*Contact Clearance, name=clear1, adjust=YES
** 
** INTERACTION PROPERTIES
** 
*Surface Interaction, name=INTPROP-1
*Cohesive Behavior, eligibility=ORIGINAL CONTACTS
1e+06.,1e+06.,1e+06.
*Damage Initiation, criterion=MAXS
60.,60.,60.
*Damage Evolution, type=ENERGY, mixed mode behavior=POWER LAW, power=2.
2.2, 8.4, 8.4
*Surface Interaction, name=INTPROP-2
*Surface Behavior, pressure-overclosure=HARD
*Distribution Table, name=PART-1_PART-1_TEXGENORIENTATIONVECTORS_Table
coord3d, coord3d
** ----------------------------------------------------------------
** 
** STEP: Step-1
** 
*Step, name=Step-1, nlgeom=YES
*Dynamic, Explicit
, 100.
*Bulk Viscosity
0.06, 1.2
** Mass Scaling: Semi-Automatic
** Whole Model
*Variable Mass Scaling, dt=1., type=below min, frequency=1
** 
** BOUNDARY CONDITIONS
** 
** Name: Disp-BC-1 Type: Symmetry/Antisymmetry/Encastre
*Boundary
CONSTRAINTSDRIVER1, ENCASTRE
** Name: Disp-BC-2 Type: Displacement/Rotation
*Boundary, amplitude= AMP-1
CONSTRAINTSDRIVER0, 3, 3, 0.1
** 
** INTERACTIONS
** 
** Interaction: general_contact
*Contact, op=NEW
*Contact Inclusions
SURFACE-YARN0, SURFACE-MATRIX
SURFACE-YARN1, SURFACE-MATRIX
SURFACE-YARN2, SURFACE-MATRIX
SURFACE-YARN3, SURFACE-MATRIX
SURFACE-YARN4, SURFACE-MATRIX
SURFACE-YARN5, SURFACE-MATRIX
SURFACE-YARN6, SURFACE-MATRIX
SURFACE-YARN7, SURFACE-MATRIX
SURFACE-YARN8, SURFACE-MATRIX
SURFACE-YARN9, SURFACE-MATRIX
SURFACE-YARN10, SURFACE-MATRIX
SURFACE-YARN11, SURFACE-MATRIX
SURFACE-YARN12, SURFACE-MATRIX
SURFACE-YARN13, SURFACE-MATRIX
SURFACE-YARN14, SURFACE-MATRIX
SURFACE-YARN15, SURFACE-MATRIX
SURFACE-YARN16, SURFACE-MATRIX
SURFACE-YARN17, SURFACE-MATRIX
SURFACE-YARN18, SURFACE-MATRIX
SURFACE-YARN19, SURFACE-MATRIX
SURFACE-YARN20, SURFACE-MATRIX
SURFACE-YARN21, SURFACE-MATRIX
SURFACE-YARN22, SURFACE-MATRIX
SURFACE-YARN23, SURFACE-MATRIX
SURFACE-YARN24, SURFACE-MATRIX
SURFACE-YARN25, SURFACE-MATRIX
SURFACE-YARN26, SURFACE-MATRIX
SURFACE-YARN27, SURFACE-MATRIX
SURFACE-YARN28, SURFACE-MATRIX
SURFACE-YARN29, SURFACE-MATRIX
SURFACE-YARN30, SURFACE-MATRIX
SURFACE-YARN31, SURFACE-MATRIX
SURFACE-YARN32, SURFACE-MATRIX
SURFACE-YARN33, SURFACE-MATRIX
SURFACE-YARN34, SURFACE-MATRIX
SURFACE-YARN35, SURFACE-MATRIX
*Contact Property Assignment
 ,  , INTPROP-2
SURFACE-YARN0 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN1 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN2 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN3 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN4 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN5 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN6 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN7 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN8 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN9 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN10 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN11 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN12 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN13 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN14 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN15 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN16 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN17 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN18 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN19 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN20 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN21 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN22 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN23 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN24 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN25 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN26 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN27 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN28 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN29 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN30 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN31 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN32 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN33 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN34 , SURFACE-MATRIX, INTPROP-1
SURFACE-YARN35 , SURFACE-MATRIX, INTPROP-1
*Contact Formulation, type=PURE MASTER-SLAVE
 , SURFACE-MATRIX , SLAVE
**
** OUTPUT REQUESTS
** 
*Restart, write, number interval=1, time marks=NO
** 
** FIELD OUTPUT: F-Output-1
** 
*Output, field, number interval=200
*Contact Output
CDISP, CFORCE, CSDMG, CSMAXSCRT, CSMAXUCRT, CSQUADSCRT, CSQUADUCRT, CSTRESS, CTHICK
** 
** FIELD OUTPUT: F-Output-2
** 
*Node Output
CF, RF, U
** 
** FIELD OUTPUT: F-Output-4
** 
*Element Output, directions=YES
LE, PE, PEEQ, PEMAG, S
** 
** FIELD OUTPUT: F-Output-3
** 
*Element Output, directions=YES
NFORC, 
** 
** HISTORY OUTPUT: H-Output-1
** 
*Output, history
*Node Output, nset=CONSTRAINTSDRIVER0
RF1, RF2, RF3, U1, U2, U3
*End Step

Hope this was helpful!

Best wishes,
George