(I was certain I sent out a summary of answers to my original post, but I
haven't seen it, so I'll risk repeating myself.)
I appreciate the responses to the original post. I hope there are some
other Machead engineers on this list--I know a few others, and I'd hate
to think we were the last.
>I'm not using finite element analysis myself, but there is a fink
>(http://fink.sourceforge.net) package called modulef
I checked this out. Very interesting, although I note that it isn't
compiled for the Mac as yet. Since I'm a practicing engineer I'm hoping I
can find something that I don't need to do any development work on, but I
confess the notion of somehow coming up with FEA software that's an
actual killer app is very appealing. But it takes a lot of work. Doing a
proper matrix assembly and inversion is only the beginning. I'd hoped
someone had recompiled a large general purpose FEA program like NASTRAN
or one of the SAPs for the G5 and would relate some of the pitfalls.
Source code is available for some smaller mechanical and thermal FEA
programs: Check
<http://www.engr.usask.ca/~macphed/finite/fe_resources/fe_resources.html>
I have some listings for shareware FEA, which I collected some years ago
as part of a project for MacSciTech. I've run some of the shareware using
OS 8 and they're surprisingly good, although a little small for most
design office purposes. PlastFEM is one such
<http://home.t-online.de/home/froehling/PlastFEM/PlastFEMe.html> and
there are some interesting 2D kinematics programs. If you need something
of the sort, I'm sure they's run in Classis, and can probably be
re-compiled for OS 10.
Besides COSMOS/M which is still being sold, although not supported, there
are two other pretty good large scale packages available. MacNolian
<http://www.softing.it/eng/homepage.html> and LapFEA. MacNolian is
basically educational software, but it's pretty comprehensive. It doesn't
accept text file input, which I consider a major disadvantage, but it's
completely scriptable which may amount to the same thing.
LapFEA <http://www.lapcad.com/sware_mfp.htm> began life as MSCpal, which
was the first FEA program I ran on a Mac, back in 1987. I was able to get
some pretty good mileage out of it. The original developer was
MacNeal-Schwendler, who took over NASTRAN. LapFEA retains the NASTRAN
connectivity, but it comes with a CAD-based modeller that looks pretty
good. It runs on OS9 and Classic, but a straight OS 10 version is on the
way.
I've also run a fairly simple Mac CFD program called Quick'n Simple. I
get a couple of hits from a Google search on Quick'n Simple,
<http://www.me.pdx.edu/~gerry/QnS/>. It only handles laminar flows, and
may not be ready for NASA, but it's fairly slick
I've used COSMOS/M for 10 years. It's a general purpose FEA package with
dynamics and non-linear capability. It's an ANSYS workalike and getting
long in the tooth. SRAC hasn't done any development on it for years, but
I still use it on a daily basis for slients who don't have their own FEA
packages. And speaking of ANSYS, rumors exist that they're looking at
doing a Mac port of ANSYS. If so I imagine it would be one of the UNIX
work station versions, although putting a real Mac interface on it and
getting rid of their wretched home-built 'GUI' would be something to see.
For my money ANSYS is the best FEA software ever written.
>We have just been through an exercise at work to get a FEM/CFD package.
>What happened highlights the problem in this area.
>The mechanical team are all PC based, because there is no high end CAD
>system on the Mac (ProE, SolidWorks, AutoCad etc.).
I'll quibble with this. Just from the demo disk alone, I think Ashlar
Vellum is as good a CAD package as exists today. Check it out at
<http://www.ashlar.com/> I don't do very much 'board design' these days,
but if I did, Vellum would be the one I'd pick. Working with a couple of
the demos made it seem like it knew what I wanted before I did. I have a
low end CAD program called Deneba CAD, which gives me connectivity to
AutoCAD for simple FEA models, if I need it, but it's nothing like
Vellum. I understand Vectorworks is a very good piece of work, but I
don't know how well it's suited for mechanical CAD.
>Because of this there is no need to look at mac based FEM/CAD systems.
You might want to continue your search with the idea of finding FEA
software or a mesher at least that can read an IGES or DXF file.
FEA/CAD interactivity is vastly overrated. It used to be the holy grail
of the CAD developers, but you don't hear so much about it these days.
ANSYS and COSMOS/M do very well with IGES input, except for sloppy CAD
usage, of which there's a great deal.
My own opinion is that designers who can use CAD effectively are very
intuitive, non-linear thinkers; FEA requires a thoroughly anal, detail
oriented user to get decent results, and it's very rare to find a good
designer who is also a good FEA user for this reason. Also the
requirements of a physical model for calculating stress or temperature
are much different than the requirements of an 'architectural' model. For
example a CAD of a piping system includes all the warning placards and
valve handles and such are irrelevant to stress or thermal analysis.
Moreover the structural parts may be 3D representations of support beams
and the pipe itself. Although possible, it's stupid to use 3D hex or tet
elements to figure hoop and bending stress in pipe.
Christopher Wright P.E. |"They couldn't hit an elephant at
email@hidden | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw
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