Analytical and experimental study on active control of structurally radiated sound from an elastic cylindrical shell.

Abstract

This paper presents an analytical and experimental study on active control of structurally radiated sound from an elastic cylindrical shell. An analytical model is developed for the active structural acoustic control (ASAC) of the cylindrical shell. The structural response of a cylindrical shell to the harmonic point force is derived by applying the modal supposition method. Expressions for the far-field radiated sound pressure and radiated sound power are derived by using the Kirchhoff–Helmholtz integral and the appropriate Green’s function. Both global and local control strategies are considered. The optimal control forces corresponding to each control strategy are obtained by using the linear quadratic optimal control theory. Numerical simulations are performed to examine and analyze the control performance under different control strategies. Results show that using point force as the control input of the ASAC system can achieve the global sound attenuation of the cylindrical shell at resonance frequencies. Better control performance can be obtained under the control strategy of minimization of the radiated sound power in terms of the radiated sound power. However, control spillover may occur at off-resonance frequencies with the structural kinetic energy minimization strategy. ASAC experiment was implemented, good agreement was observed between the numerical and experimental results, and successful attenuation of structural vibration and radiated sound was achieved.