About

Mefisto is the acronym of Mechanical Field Simulation Tools, i. e. it is not a ready to use analysis software, but a toolbox, containg a set of GNU Octave functions for the numerical analysis of mechanical field problems. Currently, Mefisto provides tools to solve linear problems in solid mechanics (Finite Element Method), in steady aerodynamics (Vortex Lattice Method) and in steady and unsteady aeroelasticity.

Development of Mefisto initially started as accompanying software of an undergraduate course on FEM, to be able to demonstrate some effects that are difficult to demonstrate using commercial software. Later, it was enhanced so that it could serve as demonstrator and software used by the students for their homework in graduate courses on structural dynamics and on aeroelasticity. Mefisto should not be considered a competitor of commercial software. The main objective is research and teaching.

Mefisto is free software, available under the GNU General Public License. It is fully documented open software.

Features

The current version of Mefisto is 2.6. It contains tools to solve linear problems in solid mechanics, aerodynamics and aeroelasticity and an interface to Gmsh for pre- and postprocessing.

• Solid Mechanics
• Finite Element Method
• 2-dimensional elements: rod and beam elements, isoparametric membrane elements
• 3-dimensional elements: rod and beam elements, linear membrane elements, membrane elements with drilling dofs, shell elements
• Analysis
• Linear static analysis
• Normal modes analysis
• Direct and modal frequency response analysis
• Direct and modal transient response analysis
• Modal effective masses and modal static strain energies
• Aerodynamics
• Vortex Lattice Method
• Steady Vortex Lattice Method
• Time-Harmonic Vortex Lattice Method
• Analysis
• Steady aerodynamics of lifting surfaces
• Trim analysis
• Aeroelasticity
• Analysis
• Steady aerodynamics of lifting surfaces
• Static divergence analysis
• Trim analysis
• Flutter analysis
• Frequency response analysis: gusts and manoeuvres
• Interfaces
• Gmsh for pre- and postprocessing

New Features and Enhancements in Version 2.6

• New Features
• Biconjugate gradient solver for problems in static aeroelasticity
• Reaction loads for normal modes
• Linear constraints for solid components
• Enhancements
• Improved solution method for static and trim problems in aeroelasticity requires considerably less memory and is much faster.
• Easy implementation of user defined beam cross sections
• Function mfs_meffmass has optional output argument mem.
• Output of resultants of applied loads and reaction loads
• Changes
• Beam sections Zr and Zl have been replaced by beam section Z. The old definitions are still supported but have been removed from the documentation.
• Bugs fixed in 2.6a
• Crash of mfs_import if there are gaps in the physical group numbers
• Wrong handling of user defined rigid body degrees of freedom in case of linear constraints
• Wrong processing of control surface motion in aeroelastic frequency response analysis

Requirements

Mefisto 2.6a has been tested with the following versions of GNU Octave:

• 8.4.0 on Linux systems
• 8.1.0 on Windows systems

It may also run with older or newer versions of GNU Octave, but this has not been tested. Mefisto will not run with Matlab.

Download

• Version 2.6a (last update: 02/15/2024)

Installation

After downloading, unpack file mefisto_2.6.zip. Then, you have to make sure GNU Octave will find the Mefisto functions. You can do this by running script install.m. You find this script in the directory where you unpacked the zip file.

addpath("path_to_mefisto/src"); (on Linux systems)

or addpath('path_to_mefisto\src'); (on Windows systems)

to file .octaverc where path_to_mefisto has to be replaced by the actual name of your installation path. File .octaverc should be located in your home directory.

Links

• GNU Octave Homepage
• Gmsh Homepage