Last months I’ve been
very stressed involved in a pretty project at the GME. Some years ago, my coordinator Jacobo Díaz wrote a program called MEFLAP that created a FEM model with shell elements (with orthotropic materials definition)of voided slab for bridge decks. MEFLAP was conceived as an independent program that called COSMOS/M by Structural Research & Analisys Corporation to run analysis and show results. MEFLAP was written in DEC’s Visual Fortran.
Well, SRAC dissapeared, DEC was taken over by Compaq that was taken over by HP. So, you guessed it, MEFLAP is now a bunch of useless code (the binaries worked well with WinXP but hardly with Vista or Win7). It is the usual result if you use non standard programming languages and privative software.
We have not a free/libre replacement for non linear, FEM analisys programs today. So, if you are going to use a privative program, at least you must use the best. And Simulia Abaqus from Dassault Systèmes is a very good choice. Why? Because it’s a very advanced program with important aids for Civil, Mechanical, Aerospatial Engineering. Because it runs on Unix systems (last versions run on RHEL6 compatible GNU/Linux distributions). And because you can extend/customize Abaqus with a standard, powerful language: Python.
Abaqus write the user sessions as a sequence of Python commands. In fact the CAE has an interactive interpreter so you can run commands in it. It has an scripting interface that runs a Python script. And you can modify the GUI calling Python bindings for the FOX library (that it’s also free software).
The first step was to write a Python script (‘the core‘) that sequentially got the intial parameters, made numerical transformations, defined the final model and passed it to Abaqus via input (.inp) file. Then Abaqus run the analisys. And, when the script recovered the control, it made transformations on the database in order to get the real stresses that the structure bears.
When the script was tested and the results were right I wrote a easy GUI for introducing the initial parameters more easily. So the total program, called now VoidSlab, is launched as an Abaqus plugin.
So I have been very happy learning Abaqus (and improving my Python). I think Dassault are making a great job. And… errr… I wish they release it as free/libre software someday. Why not? Blender showed the way But if they don’t release the code, and GME leave Abaqus, we still can use the core to create voided slab models in another program.