Active attenuation of sound transmission through a soft-core sandwich panel into an acoustic enclosure using volume velocity cancellation

Abstract

In this paper, active control of harmonic sound transmitted through a soft-core sandwich panel into a rectangular enclosure is studied. As it has already been shown for the low frequency region, the noise transmission through a soft-core sandwich panel mainly occurs due to the flexural and the dilatational modes. Therefore, in this study, volume velocity cancellation control strategy is used to control these modes, and achieve sound attenuation in a broad frequency range. Point force and uniformly distributed force actuators are used as the secondary actuator to cancel the volume velocity of the bottom faceplate, which opens to the cavity, of the sandwich panel. Cancelling the net volume velocity of the bottom faceplate is compared not only in terms of the reduction in sound transmission through the sandwich panel into cavity but also in terms of the faceplate velocities. Also, the effectiveness of the volume velocity cancellation strategy has been studied for different values of isotropic loss factor of the core. Sound transmission into the cavity has also been calculated by considering the effect of cavity pressure on the sandwich panel. Numerical studies indicate that the active control method controls both the flexural and the dilatational modes of the sandwich panel and therefore, attenuates significant amount of sound pressure inside the cavity irrespective of the isotropic loss factors of the viscoelastic core in a broad frequency range. Also a finite element study has been done in the commercially available COMSOL Multiphysics software to compare with the analytical results.

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

“…Multiplying the mode shape equation (13) with equations (22) and (23) and integrating over the area of the panel, and applying Fourier transformation with some algebraic manipulations, the velocities of panels 1 and 2 can be obtained as,…”

“…Volume velocity of a panel can be determined by the summation of the product of velocity and the corresponding elemental area of each element where the volume velocity sensors are located. Therefore, the volume velocity of each element where the volume velocity sensors are located can be written as, [21][22][23] Q…”

“…It has been found that the volume velocity control strategy is able to attenuate large amount of sound power. 21,22 However, this strategy is less effective at higher frequencies because of the number of sensors required for reasonable attenuation, in many situations, is too large for practical purposes. 23–26 A recent control metric, termed composite velocity (also referred to as weighted sum of spatial gradients or WSSG) has shown promise in resolving these issues.…”

“…Volume velocity of a panel can be determined by the summation of the product of velocity and the corresponding elemental area of each element where the volume velocity sensors are located. Therefore, the volume velocity of each element where the volume velocity sensors are located can be written as, 21–23 where Q is the net complex volume velocity, ax=a/aNsxNsx and by=b/bNsyNsy, where Nsx and Nsy are the number of sensors placed in X and Y directions, respectively. So, the optimal secondary source strength can be found by minimizing the square of the volume velocity.…”

Elasto-acoustic response damping performance of a smart cavity-coupled electro-rheological fluid sandwich panel

“…Sahu et al. [39] used point force and uniformly distributed force actuators for broad-band active control of harmonic sound transmitted through a soft-core sandwich rectangular panel into a backing rectangular enclosure, based on the volume velocity cancellation (VVC) control strategy. Just recently, Jeong et al.…”