Decoupling Structural Acoustic Systems: Investigation of Radiation Damping Mechanisms

Abstract

In the framework of the present project within the DFG priority program 1897 "Calm, Smooth and Smart," dissipation of kinetic energy of vibrating structures into the acoustic far field is studied. It can be understood as radiation damping and is particularly relevant for weakly damped lightweight structures, music instruments and underwater applications. In this paper, the coupled equations of time-harmonic elastodynamics and acoustics are addressed respectively by means of finite and boundary element methods and solved monolithically. The loss factor, which quantifies the extent of radiation damping, is determined subsequent to a harmonic analysis by relating radiated sound power to structure-inherent power. First steps towards more efficient numerical formulations, which enable the consideration of radiation damping in structural simulations, are outlined. They comprise forming the Schur complement and a polynomial approximation of the resulting acoustic impedance matrices.

Identification of Radiation Damping Using a Coupled FE/BE Formulation and a Nonlinear Eigenvalue Solver

“…The results display good agreement and verify the proposed numerical scheme. In the case of a harmonic analysis, the radiation loss factor that quantifies the extent of acoustic radiation damping can simply be obtained by relating the radiated sound power to the power corresponding to the vibrational energy of the panel [3]. It is given in Fig.…”