Investigation on identifying structural modes by sound pressure signals

• DOI: 10.1007/s00502-009-0641-5
• Publication Date: 2009-06-23T06:11:41Z
• Authors: J. Prezelj; D. Černe; L. Ottowitz; M. Čudina; H. H. Priebsch
• Keywords: 0103 physical sciences; 01 natural sciences

Different methods for a visualization of plate vibration modes are compared: a laser scanning vibrometer, a microphone scanning in a very near field, a near field acoustic holography, an analytical calculation, and a finite element method calculation. A plate with dimensions of 380×382×2.9 mm was used for the experiment. During measurements for acoustic holography and during the scanning with a pressure microphone the plate was excited with a shaker, using a white noise signal, in the frequency range from 20 Hz to 6 kHz. Different methods provide similar results. However, each method is intended for a different frequency range and for different applications. Results of the near field acoustic holography and of the scanning with the pressure microphone in a very near field are relative and can only be used for mode shape identifications, while the laser scanning Doppler vibrometer can produce traceable results.