TRANSIENT SOUND FIELDS FROM IMPACTED PLATES: COMPARISON BETWEEN NUMERICAL SIMULATIONS AND EXPERIMENTS

A comparison between measured and simulated transient acoustic fields generated by a thin rectangular impacted steel plate is reported. The plate vibration is modelled in the time domain using a finite difference scheme of second-order in time and fourth-order in space (2-4 scheme) and the radiated acoustic pressure is obtained by solving numerically the Rayleigh integral equation by using a simple Boundary Element Method (trapezoidal rule). The simulated results are evaluated in the form of the spatial pressure distribution at times short-after the impact excitation. The measurements are performed using an optical method: pulsed two-reference-beam holographic interferometry. Results in the form of 2-D projections of the acoustic pressure field are obtained and compared with the simulations. A high degree of similarity is found between the measured and simulated sound fields.