Hi All,
I have provided a python code (at the end) which I used to generate a 2D biaxial plain woven 30 degree braid. The architecture of the RVE has two yarns running at +30 degree and -30 degree to the vertical axis. I observe that the volumes of the two yarn are different (0.102285 mm3 for yarn_0 and 0.102216 mm3 for yarn_1). However I was expecting the volume to be same in both the yarns.
What correction should I make in the code to get same volume in both the yarns..?
I will be grateful for your help/inputs.
Have a great weekend..!
Thanks and Regards,
Hemanth T N
Different volumes of yarn
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Hemanth_T_N
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Different volumes of yarn
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Re: Different volumes of yarn
HI Hamanth,
Sorry for the slow reply. I'm out of the country on business this week - I'll take a look at your model when I'm back in the office next week and get back to you then.
Best wishes,
Louise
Sorry for the slow reply. I'm out of the country on business this week - I'll take a look at your model when I'm back in the office next week and get back to you then.
Best wishes,
Louise
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Hemanth_T_N
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Re: Different volumes of yarn
Hi Dr. Louise,
No problem, I will be happy to have your reply next week.
Have a Nice travel..!
Warm Regards,
Hemanth T N
No problem, I will be happy to have your reply next week.
Have a Nice travel..!
Warm Regards,
Hemanth T N
Re: Different volumes of yarn
Hi Hemanth,
Which function did you use to calculate the yarn volume? This isn't included in your script.
Taking a brief look, I would say that the most likely source of the error is the fact that you've used such a low resolution for your yarns. The volume is calculated based on the surface mesh so if you use such a low resolution then the volume calculated will be lower than the actual volume because there aren't enough section points to accurately represent the volume. Although it would appear that the two yarns should be the same they have different coordinates and so differences in the computation could make the difference that you point out.
One other thing that I noticed is that your yarn repeats don't exactly match the size of the domain (1.7321 instead of 1.732).
Hope that helps. If you still have issues let me know which method you used to calculate the volume and I'll take another look.
Louise
Which function did you use to calculate the yarn volume? This isn't included in your script.
Taking a brief look, I would say that the most likely source of the error is the fact that you've used such a low resolution for your yarns. The volume is calculated based on the surface mesh so if you use such a low resolution then the volume calculated will be lower than the actual volume because there aren't enough section points to accurately represent the volume. Although it would appear that the two yarns should be the same they have different coordinates and so differences in the computation could make the difference that you point out.
One other thing that I noticed is that your yarn repeats don't exactly match the size of the domain (1.7321 instead of 1.732).
Hope that helps. If you still have issues let me know which method you used to calculate the volume and I'll take another look.
Louise
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Hemanth_T_N
- Regular
- Posts: 24
- Joined: Tue Sep 18, 2018 11:41 am
Re: Different volumes of yarn
Hi Dr. Louise,
After exporting the TexGen generated mesh as a voxel file in abaqus .inp format. I can extract the element volumes from abaqus CAE, which can then be summed to get the volume of desired element set. I tried your suggestion of increasing the resolution (to 30), but the volumes of the two yarns are not exactly the same , They have difference of 0.1% (yarn_0: 0.10850705 mm3, yarn_1: 0.10838236 mm3).
I have two more queries.
1) With the domain that I have selected (which is a dimension of a valid Representative volume element), the images of opposite faces are not exactly the same.
Could you please throw some light on how to modify the python script (attached for your kind perusal) to get exact images of opposite faces in the x-direction and y-direction.
2) I get following messages (in red) in TexGen Output box while the exporting the mesh, though they vanish after some time
"unable to calculate repeat limits"
"Unable to build slave nodes, not enough master nodes specified"
what do they mean and where should I look , to get rectify these warning messages.
please do let me know if you need additional information or clarification.
Thank you for your continued advice and support.
Warm Regards,
Hemanth T N
After exporting the TexGen generated mesh as a voxel file in abaqus .inp format. I can extract the element volumes from abaqus CAE, which can then be summed to get the volume of desired element set. I tried your suggestion of increasing the resolution (to 30), but the volumes of the two yarns are not exactly the same , They have difference of 0.1% (yarn_0: 0.10850705 mm3, yarn_1: 0.10838236 mm3).
I have two more queries.
1) With the domain that I have selected (which is a dimension of a valid Representative volume element), the images of opposite faces are not exactly the same.
Could you please throw some light on how to modify the python script (attached for your kind perusal) to get exact images of opposite faces in the x-direction and y-direction.
2) I get following messages (in red) in TexGen Output box while the exporting the mesh, though they vanish after some time
"unable to calculate repeat limits"
"Unable to build slave nodes, not enough master nodes specified"
what do they mean and where should I look , to get rectify these warning messages.
please do let me know if you need additional information or clarification.
Thank you for your continued advice and support.
Warm Regards,
Hemanth T N
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- Face Images of RVE & python script.docx
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Re: Different volumes of yarn
Hi Hemanth,
If you export the textile as a voxel mesh this is an approximation to the actual textile. Whether the voxels are assigned to a yarn or to the matrix is dependent on whether the centre point of the element is in the yarn or matrix. This may vary between the two yarns depending on the voxel resolution that you have selected. If you want a better verification of the volumes I suggest that you do a volume mesh export, which will generate a conformal mesh of the yarns, and then check the yarn volumes.
I have run your script and the opposite faces seem to be the same. The images that you have sent look like they have the original low resolution so I wonder if these were generated before you corrected the domain size? I have generated a volume mesh and confirmed that matching meshes are generated for opposite faces.
The error messages that you see are because you have created a list of 3 yarns but then not assigned any parameters to the third. If you remove the third CYarn() declaration from the Yarns list these will disappear.
Hope that helps,
Louise
If you export the textile as a voxel mesh this is an approximation to the actual textile. Whether the voxels are assigned to a yarn or to the matrix is dependent on whether the centre point of the element is in the yarn or matrix. This may vary between the two yarns depending on the voxel resolution that you have selected. If you want a better verification of the volumes I suggest that you do a volume mesh export, which will generate a conformal mesh of the yarns, and then check the yarn volumes.
I have run your script and the opposite faces seem to be the same. The images that you have sent look like they have the original low resolution so I wonder if these were generated before you corrected the domain size? I have generated a volume mesh and confirmed that matching meshes are generated for opposite faces.
The error messages that you see are because you have created a list of 3 yarns but then not assigned any parameters to the third. If you remove the third CYarn() declaration from the Yarns list these will disappear.
Hope that helps,
Louise