SfePy November 2012

sfepy@python.org

7 participants
11 discussions

Re: Torque
by Robert Cimrman 09 Mar '18

09 Mar '18

In examples/large_deformation/hyperelastic.py a rotation by displacements is applied. By using a similar function the vectors defining the force couples could be defined for dw_surface_ltr (IMHO). Does it make sense? r. ----- Reply message ----- From: "Andre Smit" <freev...(a)gmail.com> To: <sfepy...(a)googlegroups.com> Subject: Torque Date: Sat, Dec 18, 2010 05:10 What is the best way to apply a torque load to a model? -- Andre -- You received this message because you are subscribed to the Google Groups "sfepy-devel" group. To post to this group, send email to sfepy...(a)googlegroups.com. To unsubscribe from this group, send email to sfepy-devel...(a)googlegroups.com. For more options, visit this group at http://groups.google.com/group/sfepy-devel?hl=en.

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1D line elements in SfePy
by Nimish 22 Jan '16

22 Jan '16

I am currrently looking for FEM packages to help me solve a system of beams and columns, basically a collection of 1D bernoulli/timoshenko line elements. I started reading SfePy docs and i am getting the idea that doing the above is not really possible here, am i right? Are only 2D area elements permitted in SfePy? Or is there any direct support for solving 1D line elements too.. Cheers Nimish

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Evaluate a solution in the arbitrary point in the domain
by Alec Kalinin 03 Apr '14

03 Apr '14

Dear SfePy users, Is it possible to evaluate a solution not only in the FEM mesh node, but in any arbitrary point in the domain with the given (x, y, z) coordinates? For example, consider Dirichlet problem for Poisson equation. We apply essential boundary conditions on the surface nodes and after the problem has been solved we have the solution vector, i.e. vector of values in the FEM mesh nodes. But I want to know the solution in point v(x, y, z) that is not FEM mesh node. What is the best way to obtain solution in this point v? Sincerely, Alec Kalinin

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Modeling an adjustable X-ray optic
by Tom Aldcroft 21 May '13

21 May '13

I'm working on modeling a next-generation X-ray mirror for which the shape can be actively controlled by use of many thin piezo-electric actuators mounted on the mirror surface. The mirror is basically a glass conical paraboloid with a 1 meter radius and 200 micron thickness (e.g. http://en.wikipedia.org/wiki/X-ray_optics). Our project is currently using a proprietary FEA package, but the model setup and turnaround time is slow, in part because there is only one part-time engineer who can run it. SfePy looks like a great package and we're hoping that it could be used to automate running a large number of different cases. I've spent some time reading the documentation but I have a few questions that I hope can be answered before going too much further. I want to apologize in advance if some of my wording is imprecise, I have a physics background but this topic is a bit outside my realm... - Is SfePy appropriate for this problem? - If a specify a grid with about 800 x 400 points (azimuthal, axial) and about 10 boundary conditions (corresponding to mount points), what is the rough order of magnitude of time to compute the solution? Is it seconds, minutes, hours, or days? - The linear elastic examples show a problem with a specified displacement. How do I specify an input force? The piezo essentially provides a tensile force along the surface. - Is there a way to specify the problem and solve in cylindrical coordinates? This is the natural coordinate system. - How do I specify 6-DOF constraints which correspond to the mirror mounts? Thanks in advance for any help! Tom Aldcroft

3 6

VariableTimeStepper
by Bjarke Dalslet 29 Nov '12

29 Nov '12

Hello SfePy users. A question: Is the VariableTimeStepper usable yet? Is there a "proper" way to use it? Are there any examples I have overlooked? I have tried to manually replace it, i.e.: ### time_solver.ts=VariableTimeStepper(0.,30.,dt=0.001,step=0.,n_step=30001.) problem.ts=time_solver.ts.copy() ### but this throws up problems when using the problem.advance(ts). As far as i can see the ProblemDef.update_time_stepper(ts) and the ts.set_from_ts(ts) functions are not compatible with the VariableTimeStepper subclass, and does not copy the n_step0 and dt variables correctly. But then again I might just be doing it wrong ;D Hope that somebody can help me!

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ANN: SfePy 2012.4
by Robert Cimrman 25 Nov '12

25 Nov '12

I am pleased to announce release 2012.4 of SfePy. Description ----------- SfePy (simple finite elements in Python) is a software for solving systems of coupled partial differential equations by the finite element method. The code is based on NumPy and SciPy packages. It is distributed under the new BSD license. Home page: http://sfepy.org Downloads, mailing list, wiki: http://code.google.com/p/sfepy/ Git (source) repository, issue tracker: http://github.com/sfepy Highlights of this release -------------------------- - initial support for hierarchical basis on quadrilateral and brick elements - unified C/Cython structures for reference mappings - new linear combination boundary condition: edge direction - new examples showing some advanced features For full release notes see http://docs.sfepy.org/doc/release_notes.html#id1 (rather long and technical). Best regards, Robert Cimrman and Contributors (*) (*) Contributors to this release (alphabetical order): Bjarke Dalslet, Vladimír Lukeš, Matyáš Novák

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Hyperelastic: calculate total force on surface
by oleg100 22 Nov '12

22 Nov '12

Hello! I am solving hyperelastic problem (I 'v just modify hyperelastic.py from examples). I define displacements in some surface (boundary). How can I calculate total force on the surface (integration of surface traction over all surface) ? Thanks, Oleg.

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test_poly_spaces.py failure with fresh install, ubuntu 12.04, SFE build 2012.3-git-a3a66861e7f39a68dcbdd3556fb71abc680d9ef5
by Jester Purtteman 15 Nov '12

15 Nov '12

Hello, I've searched around a bit on the forum here, issues tracker, and docs, and I have not found anything directly related to this. I'm not sure I'll even be using this piece of sfepy, but i thought I'd let someone know. I just installed on Ubuntu 12.04 and run tests, I get two failures, both in test_poly_spaces.py, something about continuity gradient failure. Anyway, I've run the tests with debug turned on and captured it to a file, which is attached, hope its helpful! I am completely new to this otherwise I would take a shot at figuring out what went wrong and be useful here. I can say that this has been a pretty smooth install process, I appear to have had no other significant problems, well done! Hopefully my learning curve is so painless! Thank you!

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Porous media - Darcy Flow
by Ivan 14 Nov '12

14 Nov '12

Hi all, I've just discovered SfePy, I'm looking for an example that can be changed for Darcy flow in porous media: \vec{q} = - K\nabla \phi where K is the hydraulic conductivity and \phi the hydraulic head. Could you please point me to some examples or relevant documentation? Cheers

2 3

Postdoc opportunity in SfePy development team
by Md. Golam Rashed 06 Nov '12

06 Nov '12

It is good to hear that the "New Technologies - Research Centre at the University of West Bohemia (Czech Republic)" is going to hire postdoctoral candidates to further improve the SfePy FE framework! See it here - http://imechanica.org/node/13523

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SfePy November 2012