Enhanced vibration damping and modal energy transfer in a smart structure

Abstract

The next challenge in the field of embedded structures is the development of an efficient, energetically autonomous vibration control technique. The proposed new approach consists in transferring energy between modes of the same structure: energy is harvested in a uncontrolled mode to increase attenuation in a targeted mode. This approach may even permit a `stand-alone' design by generating constant voltages by using the structural motion with an energy harvesting technique. The proposed electrical architecture - called synchronized switch damping and harvesting (SSDH) - is composed of a harvesting circuit (synchronized switch harvesting on inductor [SSHI]), a DC-DC converter (buck-boost topology), and a modal circuit to control vibration (similar to combining the synchronized switch damping on voltage [SSDV] and modal synchronized switch damping on inductor [SSDI] methods). The theoretical analysis and numerical simulation of this architecture addressed the transfer of modal energy through a smart structure based on an academic case: a cantilever beam. The study aimed to increase damping in a selected mode by using the energy of other modes in configurations with realistic energy distributions. The circuit and energy transfer were analyzed to determine the minimum modal contributions necessary to achieve this aim and to ensure long-term stability (steady state). Compared with traditional SSDI, the bi-harmonic excitation used with this new technique increased attenuation damping by 13 dB. The proposed general approach can be extended to the majority of complex or composite industrial structures subjected to vibration.