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Updates to SLFFEA

Updated 4/18/08



Here is a summary of the updates as of 4/18/08:

Added a lot to SLFCFD, particularly incompressibility. You can see it at:

www.slfcfd.com



Here is a summary of the updates as of 8/14/07:

After updating to a new version of GNU/Linux from Slackware 12.0 , I recompiled all my codes and got the warning:
warning: incompatible implicit declaration of built-in function 'strcpy'
warning: incompatible implicit declaration of built-in function 'strncpy'
warning: incompatible implicit declaration of built-in function 'memset'
warning: incompatible implicit declaration of built-in function 'memcpy'
warning: incompatible implicit declaration of built-in function 'sprintf'
The problem was that I didn't have the include file:
   #include < string.h >
for code containing memcpy, memset, strncpy, and strcpy and
   #include < stdio.h >
for code containing sprintf. The new GCC compiler which comes with Slackware 12.0 caught this problem which hadn't come up with the older versions. So I have gone through all releases of SLFFEA and updated the relevant files so that this warning no longer appears when compiling.

Here is a summary of the updates as of 1/17/07:

I added a package of mesh generators which I call SLFMESH. Most of the codes are already included in SLFFEA except for some shell, triangle, and tetrahedron codes which I got from outside sources. These codes are also released under the GNU License and were contributed by C. Pozrikidis and Janos Erzinger.

Here is a summary of the updates as of 12/4/06:

I made a fix of the text executables in the data file directories so that they point to the correct directory where the executables are. I had accidentally pointed them to directories that only apply to one of the computers I was working with. For instance, in the directory for the plate data:
~/slffea-1.*/data/pl/
the file plpost should look like:
../../plate/plate_gr/plpost
Before the fix, it had pointed to a specific directory on my machine.

Here is a summary of the updates as of 11/14/06:

Version 1.4 is finally here.

You can get it at the download page. There have been major changes made to the code as well as input files. Here are the most significant:

Science Code Changes
  • Expanded the quad and triangle elements.
    1. The 4 node quadrilateral element can now handle 3-D membrane problems in addition to the plane strain/stress problems.
    2. The 3 node triangle can now handle 3-D membrane problems in addition to the plane strain/stress problems.
  • The plate element is now also a 3-D element with membrane properties in addition to bending. Other changes include:
    1. It also can handle 3 node plate meshes.
    2. It has new stress and strain states xx, yy, zz and principal stresses and strains I, II, III.
    3. From the membrane, there are also x and y displacements as well as rotations in z.

  • The shell element has had some significant changes.
    1. Principal stresses and strains have been completely redone so that stress and strain zx and yz are part of the principal stress/strain calculation. This means that I have gone from having only a 2-D principal stress/strain state to a 3-D stress/strain state. I omitted this before because there is no stress/strain zz, but the stress/strain zx and yz should not have been ignored in the calculation of the principal stresses and strains. I have propagated this fix to all the older codes.
    2. Changed the name of Uz_lam to Uz_fib because this is really the displacement prjected in the e3 fiber direction rather than the e3 lamina direction. I have propagated this change to all the older codes because it is more accurate.
    3. Fixed a bug relating to the updated coordinates for modal analysis problems. In my calculation for the updated coordinates, the quantity Uz_fib(formerly called Uz_lam) wasn't being calculated for modal analysis problems. I have added the necessary code to all the older codes in addition to the current one.
    4. The way the deformed coordinates are calculated based on the undeformed coordinates has changed so that it is slightly more correct. You can read about it in the code "shwriter.c" for when I write out the coordinates of the output file. I don't think this causes very significant changes, so I am not making this change for the older codes.

Graphics Code Changes

  1. The graphics codes for the plate, quadrilateral, and triangle have been modified to display the expanded capability of the elements. This is the most significant for the plate which now has many more stress and strain states.
  2. The shell element has small modifications based on the new way updated coordinates are calculated.


I have also consolidated a lot of the redundant science and graphics codes into source files that are common to multiple elements. This has eliminated a significant amount of code. Of course, the expansion of the plate, quad, and triangle elements has added much more code.
Go here to see the previous update page listing the modifications leading to Version 1.4. .
Go here to see the previous update page listing the modifications leading to Version 1.3. .
Go here to see the previous update page listing the modifications leading to Version 1.2. .
Go here to see the previous update page listing the modifications leading to Version 1.1. .

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