Learn About Vibrations!

Learn About Vibrations!

Welcome!

The ABRAVIBE blog is where you find all the resources for learning more about vibrations. Browse and download examples for the free MATLAB/Octave ABRAVIBE toolbox. Or browse the many theory examples, videos, and resources for the book "Noise and Vibration Analysis: Signal Analysis and Experimental Procedures," by Anders Brandt!

New ABRAVIBE Version 2.01 for OMA analysis!

ABRAVIBE ToolboxPosted by Anders Brandt May 20, 2018 18:03
Unfortunately, one function for OMA analysis was not updated for the new GUI based stabilization diagram in release 2.0.

There is from now, a new subrelease 2.01 to take care of this error. If you are interested in OMA you should obtain this subrelease by downloading the zip file again.

The easiest is to download the matlab files only from here. Make sure you are logged in before clicking the link.

Sorry for the inconvenience.






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New ABRAVIBE Version 2.0 Is Released

ABRAVIBE ToolboxPosted by Anders Brandt May 13, 2018 20:44

Dear all,

After much delay, the new version 2.0 of ABRAVIBE is released! If you sign in and click "Download Toolbox" you will now receive the new toolbox.

Apart from various bug fixes, ABRAVIBE 2.0 includes some rather significant changes for you, if you are a MATLAB user:

- - New method for EMA: modified multi-reference Ibrahim time domain (MMITD)

- - We introduce operational modal analysis (OMA) by the multi-reference Ibrahim time domain method (very similar to Cov-SSI)

- - A new GUI based stabilization diagram for EMA and OMA

- - A new GUI based post processing software for making your impact testing in a completely new way! Integrate it easily with your commercial system for data acquisition through universal file export/import

- - Easier processing of time files directly into files with correlation functions or spectra

You can read the manual by following the link.



Another new thing:
Some have had problems downloading the large zip file with the entire toolbox, data etc. If you have those problems, you can now download the toolbox and ChapterExamples separately. I hope this will work better.

Regards,

Anders







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Notes On Using the ABRAVIBE Toolbox for Experimental Modal Analysis

ABRAVIBE ToolboxPosted by Anders Brandt Jun 21, 2013 18:22
This 25-page technical note presents rather comprehensive information about how modal analysis is implemented in ABRAVIBE. The first part of the note discusses some very important practical aspects of how to perform a good experimental modal analysis (EMA) test. Among the things discussed are choice of measurement points, choice of support, how to check measurement data to ensure data are of good quality, etc. These points are very important. The note states that a good EMA test is at least 80 % measurements, and only maximum 20% parameter extraction. Without good data (frequency response functions) then your EMA test is doomed!

The second part of the note presents the theory for the three methods implemented for MDOF parameter extraction, that is Prony's method (for a single FRF), the least squares complex exponential (LSCE) method (for many FRFs but only one reference), and the polyreference time domain (PTD) method (for many FRFs and several references).

Finally, the previous example for ABRAVIBE, where the three methods are compared on real measured data, is presented with some key points.

The technical note includes a checklist which will also be published in another post at this site.

If you are signed in you can download the technical note by clicking here. Otherwise, please sign in and browse the resources at the main site.

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ABRAVIBE revision 1.2 is available!

ABRAVIBE ToolboxPosted by Anders Brandt Feb 20, 2013 22:41
The ABRAVIBE toolbox for MATLAB/GNU Octave is available in a new version, revision 1.2! You can now download it by following one of the following link:
download it directly by clicking here (you will be guided through the registration and sign-in process)
go to www.abravibe.com and select "Sign In" in the upper right-hand corner, after which you will be able to download the toolbox.

Make sure you select to receive update notifications every time a new version is available when you sign up!

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