As distributed, FElt can solve the classic problems in linear statics and linear dynamics for both structural and thermal mechanics (i.e., problems of the form Kd = F, Md'' + Cd' + Kd = F , or Md' + Kd = F). It can also solve the generalized eigenvalue problem (K - lM)x = 0 and use this information in modal analysis. It can do spectral (frequency domain) analysis of transient structural problems. Nonlinear static analysis is in the works with the first cut being a simplistic static substitution scheme. The element library consists of truss, beam (Timoshenko and Euler), constant strain triangular, bilinear planar isoparametric, axisymmetric, plate bending (selective reduced integration quadrilateral), isoparametric solid (eight node brick) elements, and rod and constant temperature gradient thermal elements.
Unless it fits into one of the classes above there are no built-in solvers for your type of problem. You may be able to use burlap to write your own solver though.
The latest version of FElt, in all its incarnations, is always available via anonymous ftp from ftp.felt.sourceforge.net. As of this update, the latest version is v3.05. Information is available via the Web at
if you want to take a more serious look at some of FElt's capabilities before you actually take it for a test drive on your machine. There is an ftp mirror site at ftp.isd.uni-stuttgart.de in pub/src/FEM/Felt.
The complete version of FElt (including the X11 based graphical user interfaces) has compiled and tested on HPs, DECs, Suns, SGIs, 386/486s running Linux and SysV R3, and IBM workstations. It should do the same on any reasonable Unix system with X11R5 or R6. In general we provide binaries for Sparc stations running SunOS or Solaris and 386s with Linux, but there is no guarantee that the binaries are as up to date as the source code. When in doubt just grab the source code and build it yourself - really, it's easy.
DOS executables are available for the command-line applications felt, corduroy, yardstick, burlap, and patchwork. A simple graphical application, feltvu is also available. You need to have at least a 386 to use the DOS versions. As of v3.02 we have switched to DJGPP v2.0 and the DOS versions should run under Windows 3.1. Also as of v3.02, there are 32-bit Windows (95 and NT) versions of all the programs (including velvet). You need X server software to make velvet work of course.
With the release of WinFElt, yes there is. After an extended beta period of WinFElt v1.0 for both Windows 95 and Windows 3.1, WinFElt v1.1 for Windows 95 and Windows NT is now available. There is no velvet-like CAD-style native Windows interface, however, and we're probably not the folks to write it as neither of us have much experience with Windows programming. There may be people working on this - let us know if you're thinking about something like it and we'll try our best to make sure that people don't duplicate a lot of effort.
Well we originally chose to work with the Athena widgets because the price is right and because they allow us to maintain FElt as a 100% free product. With the current set-up anyone (in theory at least) can get and build everything they need to get FElt up and running free. If we had worked in Motif then we at least would have had to shell out for Motif for Linux and people without Motif simply would be out of luck unless they happened to be working on one of the few machines that we could provide statically linked binaries for. We also recognize that we could maintain separate GUI interfaces, but we feel that our development time is better spent on functionality rather than on constantly keeping two or more separate interfaces up to date. In addition, it's our feeling that Motif or OpenLook or any other widget set would not offer us any significant additional capabilities that we haven't already worked out with the Athena widgets.
However, if you just want a slightly different look and feel than the stylized default look of velvet then please feel free to change it - that's what Xresources are for after all. The easiest way to get a slightly more Motif look (not really the feel though) is to switch to the 3d Athena widgets. I know that these are readily available as compiled libraries for Linux and should be for some other machines as well; they're also really easy to build yourself if you are so inclined. Once you have them all you have to do is swap them for your regular Athena shared library (or re-link if you don't use shared libs); the next time you run velvet everything should be 3d. There are some recommended changes to the app defaults for velvet if you do decide to go this route, they're at the bottom of Velvet.ad in src/Velvet.
Not really - you really should have X11R5 or R6. Compiled libraries should be available for most machines. If not, source code for the X11R5 distribution is available via anonymous ftp from ftp.x.org and pre- compiled libraries should be available from many places on the net. Now that X11R6 is available you should be able to use that just as well as R5.
If you really want to do it with X11R4, then you can try the following: from ftp.x.org get three header files from the untarred R5 or R6 sources - Xfuncs.h, Xfuncproto.h, Xosdefs.h. Make a directory FElt-x.xx/inc/X11 and copy these three files into it. Then just do a regular make as described in the INSTALL file. See the notes on SGIs in the INSTALL file if you need a few more details.
Source code is available from prep.ai.mit.edu. Binaries for a wide variety of machines should also be available from various archives on the net. Building gnu binaries from source is really easy, just untar them, cd into the directory into which they unpacked, type configure and then type make.
Send one of us email (email@example.com or firstname.lastname@example.org). Please, please, please, include as much information as possible in your report. Things that are absolutely essential:
There was a real mailing list that is now dead. Instead we are manually maintaining a list of people who would like to receive periodic updates about releases and bug fixes. Send a note to email@example.com indicating that you would like your name added to such a list. Incremental release announcements and bug fixes will be posted to the mailing list. Major release announcements will be made to the following newsgroups: comp.os.linux.announce, sci.math.num-analysis, sci.engr, sci.engr.civil, and sci.engr.mechanical. So if you really want to keep up on new versions and capabilities, you should subscribe to the mailing list.
Well, FElt is obvious, right? Finite ELemenT. felt the application came first - it's the most basic interface into the system. Now when it comes to fabrics, everybody knows that velvet is smoother than felt ... thus the slickest GUI interface is called velvet. xfelt is simply xfelt because it is nothing more than an encapsulator, with no real functionality beyond that provided by felt.
After this, we start to stretch because with the felt - velvet connection we have this fabric motif to keep up on.
- Burlap is rough but functional, just like its namesake fabric. It may not be as easy to use as velvet (or maybe it is if you like scripting in Matlab-like mathematical languages) but you can do an awful lot with it.
- Corduroy has that regular ripple effect so its sort of like a mesh ...
- Patchwork, well we figured that was better than convert simply to avoid conflicts. How many systems have some local app called convert to do whatever, or how many little hacks are there called convert. It seemed common enough to us that we figured we might as well call it something different. Patchwork implies a lot of different fabrics coming together so it seemed as good as anything else.
- A yardstick is used to measure fabric ... measuring implies some sort of units.
Back to the FElt Demo Document.