چكيده به لاتين
A spatial state-space formulation based on the linear three-dimensional piezoelasticity theory in conjunction with the classical Rayleigh integral acoustic radiation model are employed to obtain a semi-analytic solution for the coupled vibroacoustic response of simply supported, arbitrarily thick, piezolaminated rectangular and circular plates, set in an infinite rigid baffle. The smart structure is composed of a transversely isotropic supporting core layer integrated with matched volume velocity spatially distributed piezoelectric sensor and uniform force actuator layers. To assist controller design, a frequency-domain subspace-based identification technique is applied to estimate the coupled fluid-structure dynamics of the system. A standard linear quadratic Gaussian (LQG) optimal controller as well as a multi-objective mixed ℋ2/ℋ∞ robust controller are subsequently synthesized and adopted for active sound radiation control of the smart panels, in the face of general electromechanical disturbances and un-modeled dynamics. The control input voltage for effective reduction of the estimated radiated power (net volume velocity) of the panel is calculated in both frequency and time domains. Numerical simulations demonstrate the effectiveness of the adopted volumetric sensing/actuating technique together with optimal LQG or robust ℋ2/ℋ∞ control strategies for suppressing low frequency sound radiation from three-layered sandwich panels in both frequency and time domains. The trade-off between dynamic performance and control effort penalty is examined in optimal LQG control scheme for two different types of loading (i.e., impulsive and broadband random disturbances). Also, superior bandwidth frequency and tracking performance of mixed-norm robust ℋ2/ℋ∞ controller in comparison to ℋ2 and ℋ∞ controllers are observed. Validity of the comprehensive elasto-acoustic model results is demonstrated by comparison with a commercial finite element package, as well as with the data available in the literature.
