FEAP User Forum
FEAP => General questions => Topic started by: Reza on August 10, 2023, 07:28:30 AM
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Dear FAEP Admins,
I want to analyze the structure of syntactic foam (consisting of aggregate particles and metal matrix matrix). Can FEAP software be a suitable option for 3D analysis and homogenization and obtaining equivalent characteristics in macro mode?
1.n my RVE model, the number of additive particles is too many. Can I bring the modeling from another software to this software?
2.Has a similar work (3D multiscale RVE analysis) been done with this software?
Best regards,
Reza
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If you have a mesh of your geometry, it should be fairly easy have FEAP read it in and then you can use the HILL feature to compute effective moduli of your RVE.
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See http://feap.berkeley.edu/wiki/index.php?title=Hill-Mandel for a simple example.
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Thank you, I am not familiar with this software and I am just reading the help of the FEAP, but some issues are unclear to me.
Can I import my 3D model in the FEAP? Or should I write the model code according to format FEAP?
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1. How is your RVE modeled? When you say there are too many particles, how many are there?
2. What is the data structure of your RVE? FEAP is a finite element data structure, nodes and element connection lists.
3. What type of analysis do you need to do? Homogenize linear properties, solve non-linear boundary value problems, or what?
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If you want to use FEAP to perform your analysis, then, yes, you need to write your data in FEAP's format, which is pretty standard, node numbers and coordinates, element numbers and connectivity. See the user manual for details.
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For example, I modeled an RVE with periodic geometry in Digimat software and attached a photo of it (The particles are porous aggregates and the matrix is aluminum).
I have to analyze this structure and get the mechanical properties and then get the mechanical properties in macro dimensions (micro scale analysis). Can I do modeling like this in software FEAP?
What is the advantage of this software compared to other similar software (such as Digimat and Abaqus)?
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FEAP can do this. The primary advantage of FEAP is that you have access to the source code. Which means you know exactly what it is doing and you can modify it if you wish. Commercial codes are great, but they cost quite a bit, and you never really know what they are doing.
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Feap can do a problem like you show, however, we require the meshing to have matching nodal locations on opposite faces. Commercial programs, such as Abaqus, can do more general cases.
Feap is mainly a research/educational program. It does have a considerable number of options. However, you may have to do some coding to be able to solve your individual problem. That is the advantage of having the source code.
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Thanks a lot. So, based on my RVE model, should I write the particle coordinates according to FEAP format?
Can I do mushing in FEAP or is it better to do it in another software?
How can I select meshes on boundary planes exactly opposite each other to apply periodic boundary condition? (Given that the outer planes intersect the particles, how can we match the elements on the outer faces facing each other?)
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I am on travel. When I return next week I will check if there is an option where mesh may not need to match completely, it has never been check to my knowledge. However, an RVE is supposed to represent a periodic type of behavior at the scale you are modeling.
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Thank you very much for your message.
In my opinion, to apply periodic boundary conditions to FE models, node-to-node constraint equations should be applied, which require similar element meshes at opposite levels of RVEs.
We need to ensure the exact alignment of the elements on opposite faces to apply the periodic boundary conditions correctly. For this purpose, since the particles intersect with the planes, software ready meshes cannot be used. (Because in this case the elements are not facing each other, and it is not possible to apply the constraint equations on the facing nodes.)
What solution does the FEAP software have for applying PBCs on the FE model?
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I tested a 2-d problem with all displacement boundary conditions on the RVE boundary and it seemed to work for an unsymmetrical mesh. These are imposed. It is not possible to use traction or periodic type conditions with unsymmetrical meshing.
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Do you mean that we must have symmetric meshes on the faces facing each other so that we can apply the periodic boundary conditions? If so, isn't it possible in FEAP to create a symmetrical mesh?
In general, what are your suggestions for solving such problems?
I think the main challenge is when the inclusions intersect with the outer planes
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Dear Prof. Taylor,
Dear FAEP Admins,
According to the attached picture in my 3D RV model, the particles intersect with the outer surfaces, to establish the periodic boundary condition (setting the same constraint equations for the boundary elements facing each other) is one of my challenges in the meshing. I meshed with several different finite element software, but the boundary meshes (the meshes on the outer surfaces) are not facing each other and I cannot select the elements facing each other and implement the constraint equations.
Does this FEAP software have a solution for this challenge?
Best regards,
Reza Sadeghpour
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The only solution in feap is to fully restrain the boundary nodes (nonzero boundary code). This should result in micro scale RVE having applied displacements that satisfy the macro scale deformation.