Unable to generate and export volume mesh to Abaqus - v 3.8

[Jagir]

Greetings,
I am trying to export a volume mesh of simple weft knit mesh (script attached) to ABAQUS. Unfortunately, the program does not terminate and no output is produced. I am not sure what is causing this, I will be extremely grateful if you could help me resolve this.

Build details:
Red Hat Enterprise Linux Server release 6.7
Compiler gcc
VTK 5.1
OpenCascade community edition 7.0

Thanks and Regards
Jagir

Terminal output
Added textile "weftknit"
Projecting volume outlines onto the x/y plane
Building yarn slave nodes
Building yarn sections
Adding yarn surface to mesh
Clipping mesh to domain
Building yarn slave nodes
Building yarn sections
Adding yarn surface to mesh
Clipping mesh to domain
Removing degenerate segments
Splitting segments at the nodes
Removing duplicate segments
Merging straight segments
Splitting segments at the nodes
Splitting segments by other segments
Identifying projected regions
Manually seeding boundary segments
Identifying region centers
Identifying list of yarns contained within each region
Meshing projected regions in 2D
Meshing basic volumes in 3D
GetNodePairs 0% complete
GetNodePairs 10% complete
GetNodePairs 20% complete
GetNodePairs 30% complete
GetNodePairs 40% complete
GetNodePairs 50% complete
GetNodePairs 60% complete
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GetNodePairs 80% complete
GetNodePairs 90% complete
GetNodePairs 100% complete
GetNodePairs 0% complete
GetNodePairs 10% complete
GetNodePairs 20% complete
GetNodePairs 30% complete
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GetNodePairs 90% complete
GetNodePairs 100% complete

[louisepb]

Hi Jagir,

There doesn't seem to be a script attached..

Best regards,
Louise

[Jagir]

Opps I thought I did..
I have just pasted the text below.. in case it doesnt get uploaded again

from TexGen.Core import *
from TexGen.Export import *
import math


# Create a textile
Textile = CTextile()

# Create two yarns
Yarn1 = CYarn()
Yarn2 = CYarn()

# Define geometric constants
r = 1
sx = r * 2.5
sy = r * 10
ly = 0.75 * (sx + r)

# Add nodes to the yarns to describe the yarn path
for Yarn in [Yarn1,Yarn2]:
Yarn.AddNode(CNode(XYZ(0, 0, r)))
Yarn.AddNode(CNode(XYZ(sx + r, ly, 0)))
Yarn.AddNode(CNode(XYZ(sx, ly + 0.5 * sy, -r)))
Yarn.AddNode(CNode(XYZ(sx - r, ly + sy, 0)))
Yarn.AddNode(CNode(XYZ(2 * sx, 2 * ly + sy, r)))
Yarn.AddNode(CNode(XYZ(3 * sx + r, ly + sy, 0)))
Yarn.AddNode(CNode(XYZ(3 * sx, ly + 0.5 * sy, -r)))
Yarn.AddNode(CNode(XYZ(3 * sx - r, ly, 0)))
Yarn.AddNode(CNode(XYZ(4 * sx, 0, r)))

# Assign a constant circularcross-section
Section = CSectionEllipse(2 * r, 2 * r)
Yarn.AssignSection(CYarnSectionConstant(Section))

# Create some repeats
Yarn.AddRepeat(XYZ(4 * sx, 0, 0))
Yarn.AddRepeat(XYZ(0, 2 * sy, 0))

# Set the interpolation function
Yarn.AssignInterpolation(CInterpolationCubic())

Yarn1.SetFibresPerYarn(10)
Textile.AddYarn(Yarn1)

Yarn2.SetFibresPerYarn(20)
Yarn2.Translate(XYZ(0, sy, 0))
Textile.AddYarn(Yarn2)

# Add the textile
Textile.AssignDomain(CDomainPlanes(XYZ(0, -4*ly, -2 * r), XYZ(4 * (4 * sx), 4 * sy, 2 * r)))
AddTextile("weftknit", Textile)

#Regenerate mesh so that contact surfaces are created
tension = CLinearTransformation()
tension.AddScale(1.0,1.0,1.0)
deformer = TextileDeformerAbaqus()
deformer.SetIncludePlates(0)
deformer.AddDeformationStep(tension)
deformer.DeformTextile(Textile)

mesher = CMesher(0)
mesher.SetPeriodic(True)
mesher.CreateMesh(r'weftknit')
mesher.SaveVolumeMeshToABAQUS(r'knit.inp','singleknit')

[louisepb]

Hi Jagir,

Are you trying to create a model of just a textile or the composite? If just the textile the you need to use a different function to create the mesh.

The TextileDeformerAbaqus class that you have used is created to be used with the Abaqus dry fibre export which creates a conformal mesh of just the yarns. In this case you need to modify the last section of your code as follows:

Code: Select all

#Regenerate mesh so that contact surfaces are created
tension = CLinearTransformation()
tension.AddScale(1.0,1.0,1.0)
deformer = TextileDeformerAbaqus()
deformer.SetIncludePlates(0)
deformer.AddDeformationStep(tension)

deformer.CreateAbaqusInputFile( Textile, r'knit.inp',False)

This will produce an Abaqus model which looks like this:

Jagir.png (141.17 KiB) Viewed 8056 times

The CMesher class creates a tetrahedral mesh of both the yarn and matrix but is designed to work with more standard woven textiles. I think that it is in this part that your code hangs, but I haven't identified the problem with this yet. I think that the knitted structure probably gives issues with the way that the algorithm works.

I hope that helps,
Louise

[Jagir]

Hi Louise,
Many thanks for your help.

Regards
Jagir