Experimental Investigation of Structural Intensity Control in a Vibrating Panel Using a Finite Differencing Approach

Abstract

The active reduction of vibrational energy flow by means of structural intensity (SI) proposes to be an effective approach towards global downstream attenuation of a structure based on preliminary numerical studies. This work examines an approach on SI control by approximating the latter by finite differencing arrays of velocities. Here, only transversal waves are considered. Different levels of complexity are taken into consideration and compared to a state-of-the-art active vibration control. A feedforward controller is estimated based on the disturbance force as a reference signal. The controller minimizes the target functions, being different components of SI in order to evaluate the impact of error sensor array complexity on global reduction. Furthermore, multiple configurations of control actuators, specifically inertial shakers, are investigated. It can be shown that targeting additional internal forces benefits in a significantly lower global vibration level downstream of the error sensor positions, whilst using a less dense array of sensors with respect to wavelength of the sound. However, as already shown in numerical studies, implementing internal forces up to third order of spatial derivatives (shear forces) perform worse than a simple approach with additional angular velocity, as sensing errors amplify non-linearly.