Inproceedings,
Validation of AE-signals recorded with conventional Equipment using 3D-Scanning-Laser-Vibrometer
EWGAE 2010, Vienna, Austria, (2010)
Abstract
The work presented in this paper focuses on interpretation and explanation of acoustic emissions (AE) recorded by means of piezoelectric sensors. It is a well known fact that AE signals are changing on their way from the source to the sensor. Especially the spectral contents of the recorded signal and of the source-signal are generally not the same. Among the main influencing factors are the mechanical characteristics of the solids the sound waves travel through, of the sensor coupling and of the sensor itself as a somewhat resonant system.
For a better understanding of the impact of these factors on a recorded signal a Polytec threedimensional scanning laser vibrometer for non-contact and non-reactive acquisition of the vibration and surface wave data has been used on a geometrically simple structure (steel cuboid) in combination with conventional AE measurement equipment (i.e. a piezoelectric sensor).
The simple geometry of the chosen structure also allows for a relatively reliable numerical calculation of its natural frequencies and the associated eigenmodes – at least in the lower frequency spectrum – by means of a modal analysis using finite element methods.
