Actuator placement for shunt damping of panel structures – numerical simulation and experimental validation

Abstract

For the reason of ecologic sustainability and decreasing reserves of fossil energy sources efficiency is a great concern. A very attractive solution is the use of lightweight fiber reinforced structures. But due to high stiffness and low mass they are much more prone to vibration and noise emission. Besides passive damping or active structural acoustic control so called shunt damping offers an opportunity for noise and vibration attenuation. For broadband damping performance negative capacitance shunt networks show promising results. Actuator placement is a great concern for this concept because a good coupling is required for sufficient damping efficiency. For active noise and vibration damping a pre-design tool was developed at DLR to obtain the positions of a certain number of actuators. This algorithm has been improved by a coupled model of electric networks to obtain the closed loop transfer function of the whole structure equipped with shunted actuators to simulate network damping performance. In order to prove the simulated damping result, an experimental validation for a steel panel is presented in this paper. An actuator placement for this panel is derived with the predesign tool and a test panel is equipped with actuators according to the placement. It is investigated in a panel test stand, where vibration amplitudes can be measured with a laser vibrometer and sound power by a sound intensity probe. Finally, numerical and experimental results are compared and discussed.