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
Re: fatal: Unable to look up git.sympy.org (port 9418) (Name or service not known)
by Robert Cimrman
Hi Sven,
thanks for trying sfepy.
The correct git repo url is the github one. We need to regenerate the docs, good catch.
The current documentation is at http://docs.sfepy.org/doc-devel - at the starting page there is a link to overview of all terms. The docs are also linked with the corresponding sources.
Does it help? Feel free to ask!
r.
----- Reply message -----
From: "kassbohm" <kass...(a)gmail.com>
To: "sfepy-devel" <sfepy...(a)googlegroups.com>
Subject: fatal: Unable to look up git.sympy.org (port 9418) (Name or service not known)
Date: Sat, Feb 12, 2011 15:31
Hello,
very nice project.
Two things:
1) Following:
http://docs.sfepy.org/doc/introduction.html#installation
and doing:
git clone git://git.sympy.org/sfepy.git
I get the error-message mentioned above.
If you use git://github.com/sfepy/sfepy.git instead, all works fine.
Is this an issue? Can I repair myself? If yes: How?
2) I am a newbie to sfepy. I would like to unserstand how
hyperelastic.py works under /examples/large_deformation. For example I
would like to know, where documentation and/or the coding of the
mooney-rivlin and neo-hookean material can be found. And also about
where the terms dw_tl_he_neohooke.i1.Omega etc. are coded/documented.
Anybody out there, who would give me some hints?
Sven
8 years, 2 months
Re: [Numpy-discussion] FYI: experimental waf support for numpy (fwd)
by Robert Cimrman
FYI (Logan :)): It seem that David made quite a progress with bento.
r.
---------- Forwarded message ----------
Date: Thu, 10 Feb 2011 17:03:23 +0900
From: David <da...(a)silveregg.co.jp>
Reply-To: Discussion of Numerical Python <numpy-di...(a)scipy.org>
On 02/10/2011 04:45 PM, Sebastien Binet wrote:
> David,
>
> On Thu, 10 Feb 2011 14:30:37 +0900, David<da...(a)silveregg.co.jp> wrote:
>> Hi there,
>>
>> Following recent release of waf 1.6 and its adoption by the samba
>> project, as well as my own work on integrating waf and bento, I have
>> spent some time to build numpy with it. Although this is experimental,
>> it should be possible for people to play with it:
>>
>> https://github.com/cournape/numpy/tree/waf_build
>
> great news !
>
>>
>> You need a recent waf checkout (trunk), and you build numpy as follows:
>>
>> $waf_checkout/waf-light configure
>> $waf_checkout/waf-light build
> why don't you just put the waf executable within the numpy repository ?
Because it is still experimental, and there are some issues in waf
around tools on windows, etc... meaning I will have to follow trunk
pretty closely after those bugs are fixed.
This is also not intended to be merged. The goal really is to discover
as many issues as possible before I decide to use waf exclusively as the
build "backend" in bento instead of my own (if you are interested, there
is already a proof of concept of building simple extensions with waf
inside bento in bento repo:
https://github.com/cournape/Bento/tree/master/examples/hooks/waf/waf16)
cheers,
David
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8 years, 2 months
Re: Conference
by Robert Cimrman
I have overhauled the script, so that there are no globals, subiterations can be ended as needed etc. The traction() function is removed, the loading displacement is given simply by value. I hope it does what you intended.
It needs a patch to TimeStepper, that I will be able to upload first on Monday, so either just look at it, or fix it yourself... :)
r.
----- Reply message -----
From: "Andre Smit" <freev...(a)gmail.com>
To: <sfepy...(a)googlegroups.com>
Subject: Conference
Date: Fri, Jan 21, 2011 02:47
Robert
I believe I've sorted out the oscillation problem, which was a bug in the code. I've pasted the latest version at [1] that now converges tightly after 3 or 4 iterations. I have a few comments.
As you will see:
a) I'm runnng the solver repeatedly with increasing displacements. This was mainly because I'm unable to change the displacement variable (disp) in traction() outside of the function. Globals and lists didn't work for me here.
b) To overcome this obstacle, the displacement for each solver/displacement cycle is saved to file and read from disk in traction().
c) I iterate the problem until the force converges and then increment the displacement.
d) The element stiffness matrix (Ele) is saved to file and loaded at the start of the subsequent displacement interval.
Comments:
1) I considered adding a variable to ts, say ts.disp and adding the displacement to that, making it available in traction. I'm sure there is a better way though.
2) I also cannot terminate the ts loop and am forced to run through all ts.n_steps. This is a problem since the forces converge at different number of steps at which point I would like the loop to end.
[1] http://paste.pocoo.org/show/324169/
Andre
On Wed, Jan 19, 2011 at 10:22 AM, Robert Cimrman <cimr...(a)ntc.zcu.cz> wrote:
On Wed, 19 Jan 2011, Andre Smit wrote:
Robert - I'm trying to change the displacement (disp) in the traction
function when the force stabilizes but for some reason the scope of disp
within traction() appears different to that within calc_force(), even
though disp is defined as global. Any ideas?
old_force = 0
def calc_force(pb, ts, state):
global disp,old_force
d = state()
pb.remove_bcs()
f = pb.evaluator.eval_residual(d)
pb.time_update()
f.shape = (pb.domain.mesh.n_nod, 3)
p = []
for n in pb.domain.regions['Top'].vertices[0]:
p.append(f[n][2])
p = nm.array(p)
if abs(old_force-p.sum()) < fvar:
my_output(disp,",",p.sum())
disp -= ddisp
old_force=p.sum()
def traction(ts, coors, bc=None):
global disp
#disp = -(ts.dt*(ts.step+1))
print "traction disp: ", disp
val = nm.empty_like(coors[:,0])
val.fill(disp)
return val
I would use brute force:
globals()['disp'] = ...
You cannot really change value of a global that is immutable (IMHO)...
A common idiom is to use list instead, like:
disp = [0]
def traction(ts, coors, bc=None):
disp[0] = ...
What is the meaning of 'smix' stiffness, for strain rate
zero?
I'm not sure.
That might be the problem causing the oscillations...
r.
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Andre
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8 years, 2 months
