exporting to Abaqus

[loyal979]

Hi All,

could somebody help me with the types of files that can be exported to abaqus. for example what are the differences between exporting a STEP file, dry fiber , voxel file or volume mesh file.

Thank you in advance

Matt

[louisepb]

Hi Matt,

There is some information about using the different exports here: http://texgen.sourceforge.net/index.php ... ide#Export

The STEP and IGES exports create files in those formats with just the geometry. No other information is exported. You would then need to use other software to generate meshes of the geometry.

The dry fibre export creates a mesh of just the yarns and exports as an Abaqus.inp file with corresponding .ori and .eld files containing orientation and volume fraction information. To get a preview of the mesh which would be created you can use the Rendering->Render Textile Volume option in the GUI.

The voxel and volume mesh exports both allow for export of yarn and/or matrix. They also produce the three Abaqus files and, optionally, create periodic boundary conditions. The voxel export creates hexahedral elements. Its use to predict material properties is described here: http://texgen.sourceforge.net/index.php ... and_Abaqus
The volume mesh export creates a conformal tetrahedral mesh but, because of the algorithm used, is unsuitable for textiles containing vertical or near-vertical yarns.

Hope that helps,
Louise

[loyal979]

Thank you for the great information Louise.

So, is it possible to generate the matrix externally if I exported the model as fiber dry. for example creating the matrix in Abaqus or through using other applications?

[louisepb]

Hi Matt,

I'm not sure about that. I think that it's possible to export the geometry (stp/iges) into something like Hypermesh and then perform a Boolean operation on the matrix volume to subtract the yarn areas. I have to say that I've no experience at all of doing that so I've no idea how hard it would be.
Whether you could do a similar thing with a dry fibre mesh is an interesting question. I have to confess that I don't have much experience of using the meshing within Abaqus so I don't know what the capabilities are. The advantage there, I guess, would be that you would have your orientation and Vf information. I would be interested to hear how you get on if you try this! Let me know if there's anything I can do to help.

Best regards,
Louise

[loyal979]

Hi Louise,

I agree with you. I have been trying to generate the matrix within Abaqus and then use the dry fiber file to subtract the yarn areas but that will not work out because I need to have the geometry of the yarsn in order to subtract their areas in the matrix. I think the best way to do it is to export the geometry as a STEP file and go from there.

Matt

[louisepb]

Hi Matt,

If you're successful with that and re-mesh the yarns I have a script which will take a data file of element centre points and interrogate the TexGen model to find the orientations and create a .ori file. Let me know if that would be useful.

Best regards,
Louise

[loyal979]

Hi Louise,

Yes, please. if you could share your script with me that would be great.

is the data file of the element center points, taken from Texgen?


Thank you

Matt

[louisepb]

Hi Matt,

I will send the script. It was written by a researcher in our group who has now left. On looking at it again it doesn't seem to define the format of the file of centre points that it's reading so you may need to put some effort into working out what it actually does. Looking at it I think it assumes that it is a textile with four yarns. Hopefully it will, at least, point you in the right direction. What he basically did was generate a TexGen model, export the geometry to Hypermesh, mesh in Hypermesh and generate the file of element centre points from the elements created. He then used those centre points to interrogate the original TexGen model to get the orientations etc which is what the script does.

Hope that helps,
Louise

[loyal979]

Hi Louise,

Thank you very much. I got your email.

Matt

[loyal979]

Hi Louise,

Do you have an idea on how to generate the file of element center points in Abaqus?

Thanks

Matt

[louisepb]

Hi Matt,

You should be able to get nodal coordinates as a field output which combined with information about nodes associated with each element will enable you to calculate the element centre points using a function similar to the one implemented in the mesh class in TexGen. (Essentially it just calculates the average of the nodal points)

Code: Select all

vector<XYZ> CMesh::GetElementCenters( ELEMENT_TYPE type )
{
	vector<XYZ> ElementCentres;
	int iNumNodes = GetNumNodes(type);
	list<int>::const_iterator itIndex;
	for ( itIndex = m_Indices[type].begin(); itIndex != m_Indices[type].end(); )
	{
		XYZ Centre;
		for (int i=0; i<iNumNodes; ++i)
		{
			Centre += m_Nodes[*itIndex];
			++itIndex;
		}
		Centre /= iNumNodes;
		ElementCentres.push_back(Centre);
	}
	return ElementCentres;
}

Hope that helps,
Louise

[loyal979]

Hi Louise,

I have tried to get the nodal coordinates from the field output but I am not sure how to export them as a .txt file or any other file. please help


thanks

[louisepb]

Hi Matt,

I'm afraid that I'm not an expert in writing scripts for Abaqus but you will need to write a Python script which reads the field data and then writes it to a file. You can see an example of this in the dataHandling.py script which comes with TexGen. The CreateReportFile function in this shows how to open a file and write to it.

Hope that helps,
Louise

[Mbisram]

Hi Louise!

Would it be possible to get a copy of the orientation script also? I am also trying to generate a matrix after exporting a dry fiber file!

Best,
Marisa

[louisepb]

Hi Marisa,

I have sent the script for extracting orientations in an email.

I'm not really clear why you're doing a dry fibre export if you want the matrix? It would be better to use one of the other export options which generate the matrix elements as well as the yarn. You can use the voxel, volume or tetgen export for this.

Best wishes,
Louise