Did you know that the ABRAVIBE toolbox includes a unique GUI for processing data for impact testing ? This video describes the feature, and shows how you improve the FRF quality. To use it, you simply import your data and put it in the .imptime file format, which is documented in the ABRAVIBE user’s guide, then you can open your files and process them.
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.