Cornell Fracture Group Past News

We will save some of the news items in the News Archive.

Current Frequently Asked Questions

We will list some of the more frequently asked questions with the answers here.

1. How much memory and CPU power should I have to run FRANC2D ?
   franc2d is compiled with a fixed amount of memory for all of the Unix platforms. For the PC running under MS Windows, franc2d can be run from the CMD or DOS shell window with the "-mem" command (i.e. "franc2d.exe -mem 10000000").  You can increase the memory until your PC runs out of RAM or Virtual memory.  If you exceed the available memory, the program will simply fail to start running.  If you are running, and get the message "utlget: no free blocks" - then you have exceeded the memory initially allocated for the program.  If you are running on the PC, you can try to increase the "-mem " memory.  If you are running on a Unix platform, we might have to recompile with more initial memory.
2. How do I run osm and franc3d under MS Windows on the PC ?
   The current release of osm and franc3d will run on the PC under MS Windows using Cygwin and XFree86 (part of Cygwin - download and install all of Cygwin if you are not sure).  You will have to install the Cygwin package which can be downloaded for free.  Cygwin includes an XServer.  Once you have Cygwin installed, you need to start the XServer (use c:\cygwin\usr\X11R6\bin\startxwin.bat for example).  Once you have the XServer running, from a bash shell window (similar to DOS shell window), you can execute osm.exe or franc3d.exe.  For more information on Cygwin/Xfree86 - consult the documentation on the Cygwin www site.
3. How do I run BES and how much memory do I need ?
   BES - the boundary element code - can be run from within franc3d or from the terminal (DOS/CMD/bash) window.  You can run the cge_bes (in core) executable if the problem size will fit into memory, otherwise you should run the cocqr_bes (out of core) executable.  The in-core solver is generally much faster because the coefficient matrix is stored in RAM rather than on the hard disk.  If you try to run in-core and get the message "mmf error: memory allocation failed", then you should reduce the number of boundary elements or use the out-of-core solver.
4. How do I run osm and franc3d version 2.6 executables for the MS Windows PC platform using Exceed ?
   First, you must have Exceed installed - this is licensed software so do not ask us for it - you have to pay for it if you do not already have it.  Second, make sure the Exceed folder is in your PATH environment variable.  If you double click the WinPC_Exceed_franc3d.exe icon and it complains about missing Xlib.dll - then either you do not have Exceed or you do not have the path set correctly.  Anyone using Exceed V7.1 (and probably later versions) should change the default 'config' options.  Uncheck draft mode under "performance", the window mode should be set to multiple under "screen", and the "communication" mode should be set to passive.
5. How do I run BES from FRANC3D ?
   BES - the boundary element code - can be run from within franc3d or from the terminal.  Either way it is a good idea to define your PATH environment variable such that it includes the directory that contains the BES executables.  You can have the BES executables in the same directory as the FRANC3D executable and just run from that directory, but this is not always convenient.  Under MS Windows, you define the PATH using the Environment Variables dialog under the Advanced tab of the System Properties.
6. Does FRANC3D give wrong answers ?
   FRANC3D does not do the stress analysis.  If you are using FRANC3D with BES, then you should be aware of the limitations of BES in particular and boundary elements in general.  For instance, if you are modeling a beam in bending, you need more elements for a BES analysis to correctly predict bending deformation as compared to a uniaxial tension test and when compared to a finite element model.  The important message is that you need to do some mesh dependency studies.  That being said - there could still be a bug in the code - and you can report any problems to us.
7. What units should I use ?
   Any consistent set of units can be used; results will have units consistent with input units.

Requests, comments and questions can be sent directly to Prof. Ingraffea at ari1@cornell.edu or to the entire Cornell Fracture Group at cfg-l at www.cfg.cornell.edu.