After homogenization, you should use beam stiffness to carry out beam structural analysis, then you should obtain beam strain measures such as e_1, k_1, k_2, and k_3. You need to use the strain measures to recover the local stress. If you are using Gmsh4SC, you should be able to input all the strain measures through beam->dehomogenization and get the contour plots. The detailed stress values are arranged element by element in .sn file.
The dehomogenization in Gmsh4SC is mainly used for visualization, so it maybe not very convenient to take out the stress values according to the coordinates. So I would suggest you to use SwiftComp.exe through command if possible, because the stress results will be arranged by nodal coordinates in .sn file in this case, and you can easily take out the stress distribution along the cross section.
You can choose any position to recover the local stress field. In the tutorial, we want to take the stress distribution at the middle of the beam, so we define x=L/2.
Yes. You should use the beam stiffness matrix (or beam compliance matrix in this problem) from SwiftComp to do structural analysis. I don't know if it is a typo in the handout, I think it is more reasonable to compare the stress along the cross section at the middle of the beam. I will ask Dr. Yu to confirm his requirement. I will keep you post.
For this problem, you are asked to compare the results at the tip. The strains should not be zero.
---- Emailed forum response from wenbinyu@purdue.edu
You are right. The deflection is not zero but strains are zero. Let us change the location to the middle. Thanks for pointing out this mistake.
---- Emailed forum response from wenbinyu@purdue.edu
You are welcome. The values in the .sn file from SwiftComp.exe are arranged as "y2 y3 e11 e22 e33 2e23 2e13 2e12 s11 s22 s33 s23 s13 s12" for a 2D SG. You can also find detailed information in the SC manual (SCtheory.pdf) using the link https://cdmhub.org/resources/scstandard/supportingdocs.
I've been trying to de-homogenize in the Abaqus plugin and have had no luck... When I homogenize the model I don't get a pop-up like in the youtube tutorials. It also doesn't create a new material like in the tutorials. There is no error either. I opened up the '.sc' file and there is a stiffness matrix there but it's not right.
Has anyone been able to do this successfully in the Abaqus plugin so they can dehomogenize and compare the stresses in the center of the beam? I'm really frustrated and running out of ideas.
The homogenization results should be in the ".sc.k" file. ".sc" file is the input file for SwiftComp. Can you share your .sc file so that we can check if the ".sc" file is correct or not.
I checked your .sc file. There are at least two errors. First, the cross-section dimensions are not right. I think you created a beam section with width 1 m instead of 0.1 m. Also, the section is not centered at the origin. The y2 should range from -0.05 to 0.05 in your model. Second, the material properties are not defined corrected. It is ok to use anisotropic material properties for each layer, but you have to make sure your calculation is correct.
Please note the abaqus anisotropic material definition is different from SwiftComp. In abaqus, the stress components are arranged as "s11 s22 s33 s12 s13 and s23", but the stresses in SwiftComp is "s11 s22 s33 s23 s13 s12". The difference could cause the incorrect definition of the material properties in your model.
Thank you for those helpful suggestions, I made the two changes you suggested and am attaching my .sc file. The result is closer to what I expected but still not correct, when you get a chance can you please take a look at it and let me know what you think?
Please double check the material properties you defined. I have checked your input file, and you should get the right results if your material properties are defined correctly. You can open .sc file to see the material definition part at the bottom, then you will find some values are misplaced and some values are not right.
Kunal Samel @ on
Can some one walk me through the steps for finding the stresses through swiftcomp again? Sorry, I forgot what we did in class after the homogenization
thanks
Kunal
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Kunal Samel @ on
in the tutorial, it seems that x=L/2 was substituted to find the strains and then these were input into swiftcomp. But why at X=L/2?
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Xin Liu @ on
Hi Samel,
After homogenization, you should use beam stiffness to carry out beam structural analysis, then you should obtain beam strain measures such as e_1, k_1, k_2, and k_3. You need to use the strain measures to recover the local stress. If you are using Gmsh4SC, you should be able to input all the strain measures through beam->dehomogenization and get the contour plots. The detailed stress values are arranged element by element in .sn file.
The dehomogenization in Gmsh4SC is mainly used for visualization, so it maybe not very convenient to take out the stress values according to the coordinates. So I would suggest you to use SwiftComp.exe through command if possible, because the stress results will be arranged by nodal coordinates in .sn file in this case, and you can easily take out the stress distribution along the cross section.
You can choose any position to recover the local stress field. In the tutorial, we want to take the stress distribution at the middle of the beam, so we define x=L/2.
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Kunal Samel @ on
thanks for the quick reply!
so do we use the beam stiffness matrix from swiftcomp to do structural analysis in mathematica?
the problem asks us to find the axial stress distribution at the tip of the beam, but the strains are 0 at the beam tip ie X=L
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Xin Liu @ on
Yes. You should use the beam stiffness matrix (or beam compliance matrix in this problem) from SwiftComp to do structural analysis. I don't know if it is a typo in the handout, I think it is more reasonable to compare the stress along the cross section at the middle of the beam. I will ask Dr. Yu to confirm his requirement. I will keep you post.
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Wenbin Yu @ on — Edited @ @ on
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Lohit Gudivada @ on
Prof Yu,
Could you please explain why the strains at tip should not be zero? I have attached a screenshot where I am also getting zero strains at the tip.
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Wenbin Yu @ on — Edited @ @ on
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Kunal Samel @ on
thanks Dr.Yu, Xin Liu and Lohit!
also can u mention the order in which the columns are arranged in the sn file again please?
thanks
Kunal
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Xin Liu @ on
You are welcome. The values in the .sn file from SwiftComp.exe are arranged as "y2 y3 e11 e22 e33 2e23 2e13 2e12 s11 s22 s33 s23 s13 s12" for a 2D SG. You can also find detailed information in the SC manual (SCtheory.pdf) using the link https://cdmhub.org/resources/scstandard/supportingdocs.
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Kunal Samel @ on
thanks!
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Imad Hanhan @ on
Hi all,
I've been trying to de-homogenize in the Abaqus plugin and have had no luck... When I homogenize the model I don't get a pop-up like in the youtube tutorials. It also doesn't create a new material like in the tutorials. There is no error either. I opened up the '.sc' file and there is a stiffness matrix there but it's not right.
Has anyone been able to do this successfully in the Abaqus plugin so they can dehomogenize and compare the stresses in the center of the beam? I'm really frustrated and running out of ideas.
Any help would be appreciated.
Thanks,
Imad
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Xin Liu @ on
Hi Imad,
The homogenization results should be in the ".sc.k" file. ".sc" file is the input file for SwiftComp. Can you share your .sc file so that we can check if the ".sc" file is correct or not.
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Imad Hanhan @ on
Hi Xin,
Thanks for your help, please find attached the .sc.k file.
Thanks,
Imad
Part-1-nSG2-1D-S4Rpbc.sc.k
949 B Click to download
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Xin Liu @ on
Hi Imad,
Thanks. Can you share the .sc file instead of .k file?
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Imad Hanhan @ on
Hi Xin,
Sorry, I misread your previous message, please find attached.
Thanks,
Imad
Part-1-nSG2-1D-S4Rpbc.sc
480 KBClick to download
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Xin Liu @ on
Hi Imad,
I checked your .sc file. There are at least two errors. First, the cross-section dimensions are not right. I think you created a beam section with width 1 m instead of 0.1 m. Also, the section is not centered at the origin. The y2 should range from -0.05 to 0.05 in your model. Second, the material properties are not defined corrected. It is ok to use anisotropic material properties for each layer, but you have to make sure your calculation is correct.
Report abuse
Xin Liu @ on
Please note the abaqus anisotropic material definition is different from SwiftComp. In abaqus, the stress components are arranged as "s11 s22 s33 s12 s13 and s23", but the stresses in SwiftComp is "s11 s22 s33 s23 s13 s12". The difference could cause the incorrect definition of the material properties in your model.
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Imad Hanhan @ on
Hi Xin,
Thank you for those helpful suggestions, I made the two changes you suggested and am attaching my .sc file. The result is closer to what I expected but still not correct, when you get a chance can you please take a look at it and let me know what you think?
Thanks,
Imad
run3pbc.sc
158 KBClick to download
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Xin Liu @ on
Hi Imad,
Please double check the material properties you defined. I have checked your input file, and you should get the right results if your material properties are defined correctly. You can open .sc file to see the material definition part at the bottom, then you will find some values are misplaced and some values are not right.
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