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?
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Andre
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Hi,
I have just updated the time stepping solvers in sfepy for interactive use, as
demonstrated in the new example [1]. For basic use, ignore the probing code -
the time stepper can be used as simply as:
tss = SimpleTimeSteppingSolver({'t0' : 0.0, 't1' : 100.0, 'n_step' : 11},
problem=problem)
tss.init_time()
for step, time, state in tss():
pass
r.
[1] http://sfepy.org/doc-devel/examples/diffusion/time_poisson_interactive.html

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

Hi sfepy-devel,
The following simulation
https://github.com/materialsinnovation/pymks/blob/master/pymks/datasets/e...
used to work on SfePy version `2014.4` but no longer works on version
`2015.2`. Do you have any guidance on what went wrong? Below is a console
printout:
Traceback (most recent call last):
File "/Users/fredhohman/anaconda/lib/python2.7/sitepackages/nose/case.py",
line 197, in
runTest
self.test(*self.arg)
File "/Users/fredhohman/anaconda/lib/python2.7/sitepackages/pymks/tests/test.py",
line 12, in
test_elastic_FE_simulation_3D
model.run(X)
File "/Users/fredhohman/anaconda/lib/python2.7/site-
packages/pymks/datasets/elastic_FE_simulation.py", line 190, in run
strain_, displacement_, stress_ = self._solve(x)
File "/Users/fredhohman/anaconda/lib/python2.7/site-
packages/pymks/datasets/elastic_FE_simulation.py", line 547, in _solve
mode='el_avg'))
File "/Users/fredhohman/anaconda/sfepy/sfepy/discrete/problem.py", line
1245, in evaluate
verbose=verbose, **kwargs)
File "/Users/fredhohman/anaconda/sfepy/sfepy/discrete/problem.py", line
1186, in
create_evaluable
kwargs=kwargs)
File "/Users/fredhohman/anaconda/sfepy/sfepy/discrete/evaluate.py", line
211, in
create_evaluable
user=extra_args, verbose=verbose)
File "/Users/fredhohman/anaconda/sfepy/sfepy/discrete/equations.py", line
64, in from_conf
materials, integrals, user=user)
File "/Users/fredhohman/anaconda/sfepy/sfepy/discrete/equations.py", line
749, in from_desc
terms.assign_args(variables, materials, user)
File "/Users/fredhohman/anaconda/sfepy/sfepy/terms/terms.py", line 286, in
assign_args
term.assign_args(variables, materials, user)
File "/Users/fredhohman/anaconda/sfepy/sfepy/terms/terms.py", line 497, in
assign_args
% arg_name)
ValueError: material argument m not found!
Thanks,
Fred

Hi,
I'm trying to solve the Richards-Buckingham equation for single-phase water
flow in unsaturated porous media. Constitutive relationships and the
variational formulation are developed here:
https://www.authorea.com/users/23640/articles/61529
I created a problem description file inspired from the examples in the
diffusion section of the web site. However, the solution doesn't converge.
Maybe the variational form wrong, maybe the equations part of the PDF is
wrong, maybe its the options. I don't know. The PDF is hosted on GitHub.
https://github.com/sergeetiparent/EnvGeotech/blob/master/Richards-Bucking...
Anyone interested in giving a hand on this case? My ultimate goal is to
model solute transport in unsaturated soils.
Thanks!
Essi

I have been doing some modeling of a piezoelectric system and it works
well. One can apply a field and see the resulting deformation. I also get
how one can calculate the Cauchy strain and stress using the post-process
hook and the terms 'ev_cauchy_strain.2.Omega(u)' and
'ev_cauchy_stress.2.Omega(solid.D, u)'. But since the constitutive law for
the stress is the Cauchy term + the piezo-coupling term, how does one
evaluate the stress and output it for given displacements and fields?
Dennis

Hi,
I have a vector variable u, defined over a region omega, that I'm trying to
initialize to the uniform value (1,2):
U = Field.from_args('U', sp.float64, 'vector', omega, approx_order=1)
u = FieldVariable('u', 'unknown', U, history=1)
InitialCondition('ic', omega, {'u.0': 1., 'u.1': 2.})
This, however, initializes u to (0.,2.).
Is this intentional? Is there a better way to initialize a vector field?
The source of this behavior seems to be at the end of
sfepy.discrete.variables.FieldVariable.setup_initial_conditions:
ic_vec = nm.zeros((di.n_dof[self.name],), dtype=self.dtype)
ic_vec[eq] = vv
self.initial_condition = ic_vec
This sets every component to zero before applying the initial condition
under consideration, therefore erasing any previous initial condition.
Replacing the code above with
if self.initial_condition==None:
self.initial_condition = nm.zeros((di.n_dof[self.name],),
dtype=self.dtype)
self.initial_condition[eq] = vv
seems to solve the problem, i.e. in my example u initializes to (1.,2.).
Best,
Yaouen

Hi all,
I'm having some difficulties installing sfepy on a mac with anaconda
running OS X Yosemite. I've looked through the installation documentation
but can't seem to resolve the errors. Can anyone point me to a relevant
guide (if it exists) or have suggestions?
I can post screenshots if needed.
Thanks,
Fred

I understand (or more accurately I have followed the examples, such as
its2D_5) how to calculate the stress and strain for an elastic deformation
problem and probe along a line. What I want to do now is display the
surface of the material and color it by one of the (for example) strain
components, such as the zz component of the strain tensor. It seems like
one just has to create a pipeline in mayavi2 that uses the
ExtractTensorComponent filter but for the life of me I can't figure out how
to select a single component (such as the zz one of stress or strain) to
use to create the surface mapping. I can change the scalar mode value
in ExtractTensorComponent from "effective stress" to "component" but I
don't understand how to choose a particular component.
I hate to post what is probably a simple question but lots of searching
hasn't yielded an answer yet.
Dennis