The ABRAVIBE example PlexiModal is an example of using the ABRAVIBE
toolbox to do experimental modal analysis of a Plexiglass plate using measured data.
The example uses data measured using impact testing, and the
polyreference time domain (PTD) method with two references, to be able to
estimate the first two modes which are strongly coupled on this plate.
The example shows all involved steps such as importing and sorting data,
curve-fitting for poles and mode shapes, and evaluating the results with
a MAC matrix and animation of the modes.
This example is good to use as a template for all modal analysis tasks
with the ABRAVIBE toolbox; just replace the data imported, and the
geometry created before animation, to use the script for your modal
In addition to this, the example includes an upgrade to the ABRAVIBE toolbox revision 1.2, with a new command enhancefrf which uses singular value decomposition to reduce the measured FRFs into a smaller number of principal responses to use for the modal parameter extraction. Also the command frf2ptime is updated to use FRF enhancement by default. These two functions will be included in the next release of the ABRAVIBE toolbox. The theory of FRF enhancement is covered in chapter 15 in the book “Noise and Vibration Analysis”.
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