EasyMod, as for Easy Modal analysis

After 30 years of development, experimental modal analysis is now established as a fundamental technique for understanding the vibration behaviour of structures. The application of modal analysis underpins the theoretical and practical modelling of structural dynamic performance. Although the basic principles have been known for many years, it is only recently that a rapid and broad development of new methods has led to their widespread use and application.” (N. A. L. Lieven and D. J. Ewins, Phil. Trans. R. Soc. Lond. A, 359, p.3,2001)


EasyMod is a MatLab/Scilab toolbox for teaching modal analysis. It provides a set of functions allowing to establish the identification of modal parameters and these validation. Nowadays, circle-fit, line-fit and least square complex exponential methods are implemented. In addition, some relevant functions are offered in order to complete a modal analysis: operations on the frequency response function (FRF) , generation of FRF from mass, damping and stiffness matrices, MAC (modal assurance criterion) and modal collinearity, ...




For the purpose of universality with other software applications, universal files (UFF) are supported. UFF are initially developed in the later 1960s and early 1970 by the Structural Dynamics Research Corporation (SDRC) to standardize data transfer between computer aided design and computer aided test software packages. EasyMod supports 58 (measurement data storage), 55 (modal parameters data storage), 151 (set of FRF or coherence storage) and 15/82 (geometry), both in writing and reading.


The visualization will be performed with the help of EasyAnim that can also be downloaded from this site. You will find in the archive the necessary information to use it. Binary versions can also be downloaded directly. For immediate information, have a look at the Readme.


To have some more information, please, have a look at the user guide or these papers:

·         G. Kouroussis, L. Ben Fekih, C. Conti, O. Verlinden, EasyMod: A MatLab/SciLab toolbox for teaching modal analysis, Proceedings of the 19th International Congress on Sound and Vibration, Vilnius (Lithuania), July 9-12, 2012.  [link]

·         G. Kouroussis, L. Ben Fekih, C. Conti, O. Verlinden, « EasyMod : du développement d'un toolbox sous MatLab vers l'enseignement des bases de l'analyse modale expérimentale », 3ième Colloque ``Analyse vibratoire Expérimentale'', Blois (France), 20 et 21 novembre 2012.  [link]


Scientific publications presenting results obtained with EasyMod must include a proper reference. In order to refer to EasyMod, please add at least one of the aforementioned articles to the list of reference.




Studied examples

Some structures have studied with the help of EasyMod, the FRF measurement being performed with the commercial software Test.Lab:


A bike frame  [measurementgeometryanalysis]





A squash racket  [measurementgeometryanalysis]





An alpine ski  [measurementgeometryanalysis]






EasyMod-2.1.0.rar (March 2012)


EasyAnim-1.3.1.tgz (December 2006)


EasyAnim-1.3.1.zip (December 2006)


EasyAnim-1.3.tgz (January 2005)


EasyAnim-1.3.zip (January 2005)


Binary versions of EasyAnim: Linux/Motif, Linux/Athena (unstable) and Windows.


EasyMod and EasyAnim are free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.


EasyMod and EasyAnim are distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.



Related software

To use EasyMod, you will need a recent version of MatLab or Scilab.


Scilab is an open source, cross-platform numerical computational package and a high-level, numerically oriented programming language. It can be used for signal processing, statistical analysis, image enhancement, fluid dynamics simulations, numerical optimization, and modelling and simulation of explicit and implicit dynamical systems. MATLAB code, which is similar in syntax, can be converted to Scilab. Scilab is one of several open source alternatives to MatLab and it is distributed under the GPL-compatible CeCILL license.




Please feel free to contact me.

Prof. Dr. Ir. Georges KOUROUSSIS
University of Mons, Faculty of Engineering
Department of Theoretical Mechanics, Dynamics and Vibrations
31, Bd Dolez  |  B-7000 MONS (BELGIUM)
E-mail Georges.Kouroussis*AT*umons.ac.be