Re: Torque
by Robert Cimrman

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
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1 year, 1 month

1D line elements in SfePy
by Nimish

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
3 years, 3 months

Evaluate a solution in the arbitrary point in the domain
by Alec Kalinin

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
5 years

Modeling an adjustable X-ray optic
by Tom Aldcroft

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
5 years, 11 months

VariableTimeStepper
by Bjarke Dalslet

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!
6 years, 4 months

ANN: SfePy 2012.4
by Robert Cimrman

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
6 years, 4 months

Hyperelastic: calculate total force on surface
by oleg100

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.
6 years, 5 months

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

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!
6 years, 5 months

Porous media - Darcy Flow
by Ivan

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
6 years, 5 months