This is the site for the NEESgrid version of FEDEASLab.
FEDEASLab is a Matlab© toolbox for nonlinear structural simulations under static or transient conditions. It is an integral simulation component of NEESgrid that is particularly suitable for concept development, for education, and for simulations of small structures or models. It capitalizes on Matlab's vast array of functions and scripting capabilities. Because of Matlab's support for many data acquisition boards and FEDEASLab's modular architecture, the toolbox should be particularly useful for integrating simulation with experimental testing.
The latest version of the toolbox is Release 2.6 dated July 30, 2004 and updated on August 27, 2004 to fix a couple of bugs and for consistency with the Getting Started Guide and the manual. The Getting Started Guide provides a brief introduction and discusses typical simulation scripts. A detailed manual about toolbox architecture and capabilities is in the final stages of preparation and will be posted by Sept. 30.
A good overview of FEDEASLab is given in the presentation from the recent OpenSees/NEESgrid workshop.
A self-extracting zip file contains the p-code of all functions and several examples. A Readme file contains installation information. There is on-line help in html format for all functions that is also included in the zip file.
The functions are organized in eight (8) separate directories, as shown in the following graph. The execution of the provided Adjust_Path m-file will prepend these directories to the Matlab path. Each directory contains a Contents.m file with a brief description of each function.
The examples address different types of analysis on a 2-story steel frame. The numbers below correspond to script file names. The file and results can be viewed by clicking on the link.
- linear elastic analysis with linear combination of load cases
- linear transient response to ground acceleration by modal analysis
- linear transient response to ground acceleration by time integration
- push-over with fixed gravity loads and incremental lateral forces with force histories
- push-over with fixed gravity loads, followed in sequence by incremental lateral forces
- same as 5 with P-Δ effect and load control on lateral forces turned on
- same as 6 but with distributed inelasticity element (examples 4-6 use one-component model)
- nonlinear transient response with gravity loads and imposed ground accelerations using the distributed inelasticity element. The execution time on a 1.7GHz Pentium IV is about 12 min without saving Post at every time step; when saving Post at every time step the execution time increases to about 30 min in Matlab 7.0 and 45 min in Matlab 6.x, because of the swapping of the huge Post data structure (approximately 340MB!) in and out of memory (the above times apply for 512MB RAM)
There is also a model definition for one bay, two-story 3d braced frame.
A draft of the documentation explaining function and data structure organization will be available by mid August.
FEDEAS stands for Finite Elements in Design, Evaluation and Analysis of Structures; the name also pays tribute to the famous builder of the Parthenon in Athens, FEIDIAS. Encyclopedia Britannica gives the following account of FEIDIAS contributions to classical Greece.
last update: September 05, 2004