Active Structural Acoustic Control of a Softcore Sandwich Panel Using Multiple Piezoelectric Actuators and Reddy's Higher Order Theory

Abstract

The purpose of the present work is to theoretically investigate the active control of radiated sound power from a simply supported soft-core sandwich panel with a line moment excitation. Since noise transmission in the low frequency region through a soft-core sandwich panel mainly occurs due to flexural and dilatational modes, therefore, the focus of this study is to control these modes and achieve sound attenuation in a large frequency band. Two control methods, volume velocity and weighted sum of spatial gradients (WSSG) are used to drive three piezoelectric actuators (PZTs) attached on the exterior side of the bottom face plate. The governing equation of the sandwich panel with the PZTs is derived using the Hamilton's principle considering Reddy's third order shear deformation theory. Numerical studies indicate that while the line moment is at the mid vertical line, WSSG is able to attenuate the radiated sound power irrespective of core loss factor whereas volume velocity could not. However, both the control metrics are able to attenuate most of the structural modes, when the line moment is off the midline, and therefore, attenuate significant amount of radiated sound power in a broad frequency range. And the maximum increase in sound power is small in WSSG as compared to volume velocity. These results show that WSSG can be used as an effective control metric to mitigate low frequency sound.

Active structural acoustic control of transmitted sound through a double panel partition by weighted sum of spatial gradients

“…The minimization of WSSG will be tested as a strategy for controlling the sound power radiation and compared with the results from volume velocity. WSSG of a structure is simply the sum of scaling values multiplied with the square of transverse velocity, rocking velocity in X and Y directions, and twisting velocity and is given by, 27,28 WSSG…”

“…Composite velocity was developed as a weighted sum of spatial velocity gradients requiring only four sensors to measure, and was found to be relatively insensitive to sensor location. 27,28 Hendricks et al 29 extended this research from computer simulations and provided experimental test results for a flat simply supported plate.…”

Simulation study of active control of vibro-acoustic response by sound pressure feedback using modal pole assignment strategy

“…It is clear that in the general ASAC analysis, a quadratic cost function is formed based on the observed pressures, and the quadratic optimization theory is used to find the optimal control inputs that minimize the cost function. Besides the acoustic sensing and acoustic objective functions, structural sensing approaches 11,12 and structural objective functions [13][14][15] such as squared velocity, volume velocity, and weighted sum of spatial gradients were studied for ASAC. Berkhoff 16 discussed sensor scheme design for the active reduction of sound radiation from plates based on error signals derived from spatially weighted plate velocity or near-field pressure.…”

Active control of structures and sound radiation modes and its application in vehicles

“…Hasheminejad and Keshavarzpour 9 studied the active control problem of sound radiation for composite plates based on 3D elastic model, but they failed to consider the corresponding relationship between sound radiation modes and structural modes and the studied process was not verified by experiments. Sahu et al 10 used multiple piezoelectric actuators and Reddy's higher order theory to study the structural sound radiation problem of sandwich plates, and analyzed the influence of different parameters on sound radiation. The research was not verified by experiments.…”