Measurement and modeling of damping for time-domain structural acoustics simulations

Abstract : This work deals with the measurement and time-domain modeling of damping in structural acoustics. An experimental technique based on the plate impulse response measurement is presented to estimate the damping factor over a wide frequency band. This technique is succesfully applied to a nylon plate between 100 Hz and 15 kHz approximately. Then we present an original approach that consists in representing the measured frequency variations of damping by a digital filter that meets the criteria of causality and stability, and then in transposing it into the time domain. Time-domain simulations of the longitudinal vibrations of a nylon bar are performed to show the efficiency of our approach, where the filter parameters are estimated from the experimental data through an optimization procedure.