Investigation of a hybrid passive-active vibration-control configuration

Paper in proceeding, 2009

A theoretical investigation of wave scattering and the active modification of wave scattering at a structural junction is presented. A resonant and a non-resonant Euler-Bernoulli beam is coupled, and an external force is introduced at the junction. The purpose of the external force is to use it for feedforward control in order to manipulate the scattering properties at the junction. The objective of the investigated control law is to cancel the reflection of a bending wave in the case of an incident bending wave, i.e.~no incident bending near-field is considered. The control effort and the resulting power flow are investigated for different properties of the resonant beam. The results are discussed from the point of view of hybrid passive-active vibration damping. By introducing damping in the resonant beam and using the active force to cancel the reflection at the junction, all incidence wave power is absorbed, either in the resonant beam or by the active force. The results indicate that in order to achieve optimal passive-active damping, the impedances of the two beams ought to be similar, and the resonant beam ought to be long in comparison to the bending wavelength.