Numerical and Experimental Assessment of Acoustic Radiation Damping

This contribution reviews the recent advances in quantifying acoustic radiation damping, which accounts for a significant contribution to the energy dissipation in lightweight structures. The methodological content of this contribution centers around the acoustic boundary element method, which allows assessing the far-field sound radiation of structures involving complex geometries. Two approaches are followed to characterize the vibration of the solid structure. The first couples a boundary element model with a finite element model, which yields a flexible and purely numerical method for computing both harmonic and modal radiation loss factors. The second approach characterizes the dynamic behavior of the solid structure by an experimentally determined matrix of transfer functions. This allows to accurately reflect the actual mechanical boundary conditions and elastic material properties. The hybrid approach is particularly suitable in the low frequency range and admits application of any type of excitation. Both approaches are applied to a honeycomb sandwich panel. The effects of acoustic boundary conditions and type of excitation on radiation damping are studied.