[SciPy-user] Use of Scipy in a students final year mechanical engineering project.

Stephen Kelly stephen.kelly2 at ucdconnect.ie
Wed Aug 9 12:23:36 CDT 2006


John Hassler <hasslerjc <at> adelphia.net> wrote:
> You've gotten a lot of very good responses already.  I'd just make a
couple of comments.


Indeed I have. Thanks to all for the replies, there are certainly some
good points here. I've been very busy and having difficulty finding the
time to pursue this further. I will send my lecturer a link to this
thread, and hopfully some suitable ideas can be investigated.

William Hunter <willemjagter <at> gmail.com> wrote:

> 1) Why don't you you do a small FEA program, assuming that you have
> knowledge of this? Something simple where you can define 2D geometry
> with AutoCAD or anything that can save in DXF format. You'll have to
> read in the DXF file, represent with Matplotlib, mesh it (perhaps
> using Delaunay), apply loads and constraints and solve the system. Or
> perhaps just some aspects of this?

The urapiv project looks interesting, but might be beyond my abilities
at this time, seeing as I do not have much academic programming
experience. However, I could have more experience by next year to take
on greater challenges in a Masters role.

My current experience in python has mainly been exploratory. I've done
some tutorials, and made a few one off programs to simplify repetitive
tasks. The biggest project I've used python for was to make infoboxes on
a mediawiki website using the pywikipediabot framework. That involved
mainly string parsing of the source data, but I learned a lot about
string and array objects.

I haven't yet found the time to use scipy and see for myself what I can
do with it, but I will hopefully get the chance to do so next week. I'll
have a look around the wiki and mailing list and find some demos and
tutorials. Even if a project I do this year is not centered around
scipy, I will certainly try to use it for any computation that comes up.

Thanks again for the responses and interest in this.
Stephen Kelly.

----- Original Message -----
From: Peter Row <peter.row at gmail.com>
Date: Tuesday, August 8, 2006 3:08 pm
Subject: Re: [SciPy-user] Use of Scipy in a students final year
mechanical engineering project.
To: SciPy Users List <scipy-user at scipy.org>

> Why scipy:
> 
> Say you have a inner loop like:
> 
> X = X + F * dt
> 
> In either Matlab or scipy, it will probably work as:
> 
> temp1 = F * dt
> temp2 = X + tempF
> X = temp2
> 
> Which is slower than nessesary, because you have to assign those 
> great hunks
> of memory to temp1 and temp2.
> 
> If you use weave.inline (after doing a rapid prototype in pure 
> python -
> because debugging segfaults when you make a mess of your indicies 
> is never
> fun, or easy), you can get rid of the big temporary arrays.
> 
> You can also do this in Matlab (using CXX), but you could simply 
> plead that
> it is easier for you to do using inline.
> 
> This is a pretty trivial example. There is no limit to the number of
> intensive operations that you can't find a good vectorized function 
> for.Speaking of which, have you seen the "vectorize" command in 
> scipy? It seems
> a little slow (next to inline), but it sure beats running an inner 
> loop in
> pure Matlab or python.
> 
> Good luck,
> Peter
> 
> 
> 
> On 8/8/06, William Hunter <willemjagter at gmail.com> wrote:
> >
> > Another thought(s). Something you're likely to come across if you 
> end> up in the mechanical design field, is the use of codes...
> >
> > Why don't you write a program that can calculate the dimensions 
> of a
> > pressure vessel, according to ASME, for example? Or a gear design
> > program which will output the 3D gear? A program to design offshore
> > containers to DNV's CN 2.7-1?
> >
> > Go look at some of the add-ins available for programs like 
> SolidWorks> and Solid Edge, you might find some ideas here too.
> >
> > For programs like these the user (probably yourself one day) would
> > typically want an intuitive UI, some form of customisation, be it by
> > editing a text file with material spec's or a file specifying pipe
> > and/or flange dimensions, and DEFINITELY output in the form of a CAD
> > file (I would say DXF/IGES for 2D and StL/XML/VRML for 3D. You can
> > attempt Parasolid, ACIS or STEP, but these are not as simple as StL
> > and last mentioned is in wide use by the rapid prototyping 
> industry).> One would possibly also want to view (matplotlib) the 
> pressure vessel
> > before saving it as a DXF file for instance. Maybe add an option to
> > enter "Company and Project Details" when saving the file as a DXF...
> > There's a lot of options!
> >
> > Regards,
> > William
> >
> > On 07/08/06, John Hassler <hasslerjc at adelphia.net> wrote:
> > >
> > > You've gotten a lot of very good responses already.  I'd just 
> make a
> > couple
> > > of comments.
> > >
> > > I'm a former prof. of ChE (retired).  When I started out (a 
> long time
> > ago),
> > > industrial plants were built in several stages: beaker, bucket, 
> barrel,> > (maybe more), final plant.  You would start with bench-
> scale experiments
> > in
> > > the laboratory, and work through progressively larger "pilot 
> plants"> until
> > > you were confident that you understood the process well enough 
> to commit
> > to
> > > building the full-scale plant.  Now, design is done through 
> computer> > modeling and simulation, and pilot plants are rarely, 
> if ever,
> > used.  The
> > > same is true in all fields of engineering.  For example, 
> computer chips
> > are
> > > simulated in detail before being tried "in silicon."
> > >
> > > In spite of this, most engineers never learn to program at any 
> level> beyond
> > > the most basic.  I'm not familiar with your field, but in ChE, 
> there are
> > > "black box" programs (Aspen, ChemCad) which will do very 
> sophisticated> > modeling, without requiring much knowledge on the 
> part of the
> > operator.  I
> > > think this is unfortunate ... but then, I'm old fashioned.
> > >
> > > I'm a visiting prof. here at VaTech.  The engineering college has
> > > standardized on Matlab.  I don't like it much, for two reasons. 
> First,
> > it's
> > > outrageously expensive.  (Scilab, as an example, is free, 
> similar to
> > Matlab
> > > in basic capabilities, works under both Windows and Linux, and is
> > certainly
> > > sufficient for any but the most demanding computational
> > problems.)  Second,
> > > Matlab makes it difficult to write well-structured programs of any
> > > appreciable size.  Python-Scipy, on the other hand, is a "real"
> > programming
> > > language, which can handle VERY large programs with "grace and 
> beauty,"> and
> > > can do small programs with convenience.  The "immediate" 
> calculational> > abilities (IDLE) are more convenient than those of 
> Matlab, since you can
> > > define functions "on the fly" ... Matlab requires "m-files" for
> > functions
> > > ... and I've used Python plus Numeric to solve some reasonably 
> large FEM
> > > examples in acceptable times.
> > >
> > > So if you needed any more encouragement to look into a modeling 
> problem> with
> > > Python, perhaps this will help.
> > >
> > > (As I re-read what I've written, I guess I could have just said,
> > "Computing
> > > .. important.  Python... good."  Professors are long winded 
> ..... )
> > >
> > > john
> > >
> > >
> > >
> > > Stephen Kelly wrote:
> > >
> > >
> > > Hi,
> > >
> > > I sent this email to Eric Jones, but he recommended that I send 
> it to
> > this
> > > mailing list instead. I'm trying to see if scipy could fit into 
> a final
> > year
> > > project for my mechanical engineering course.
> > >
> > > I am a student of mechanical engineering in UCD Dublin , and 
> part of my
> > > course involves doing a final year project. We do very little
> > programming in
> > > my course, but as coding and python in particular is something 
> that> > interests me, I'd like to have some involvement in python 
> in my final
> > year
> > > project.
> > >
> > > Because my course is not centered around coding, I think I'd be 
> more> likely
> > > to be able to do a project on applying a python application 
> like scipy
> > to a
> > > problem, or using python as glue in a scripting applicatin. I 
> found> scipy
> > > while searching for an idea for a project that I could do in 
> python,> while
> > > staying within the scope of mechanical engineering and my 
> course. I'm
> > still
> > > no closer to an idea, so I thought I'd write to you to see if 
> you had
> > any
> > > ideas of what I might be able to do as a mechanical engineer with
> > > python/scipy.
> > >
> > > Something that I think might be plausible might be a simulation or
> > > computational analysis of some kind, but I would probably need to
> > justify
> > > using python for whatever I do rather than MatLab, which is the 
> industry> > standard, and the program that my lecturers are already 
> familiar with. I
> > > have never used MatLab myself, so I'm not sure what it offers.
> > >
> > > I would appreciate any thoughts you might have on this. I 
> emailed one of
> > my
> > > lecturers already, who asked me for more specific details and 
> to give
> > > thought to the type of project I would like to do.
> > >
> > > Kind Regards,
> > >
> > > Stephen Kelly
> > > ________________________________
> > >
> > > _______________________________________________ SciPy-user
> > > mailing list SciPy-user at scipy.org
> > > http://projects.scipy.org/mailman/listinfo/scipy-user
> > >
> > >
> > > _______________________________________________
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> > > http://projects.scipy.org/mailman/listinfo/scipy-user
> > >
> > >
> > >
> >
> >
> > --
> > Regards,
> > WH
> > _______________________________________________
> > SciPy-user mailing list
> > SciPy-user at scipy.org
> > http://projects.scipy.org/mailman/listinfo/scipy-user
> >
> 


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