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SPIE, Smart structures and nondestructive evaluation Conference, 26-30 April 2020, Anaheim California Konstantinos Georgopoulos-Bosinas, Nikolaos Chrysochoidis, Grigorios - Christos Kardarakos and Dimitris Saravanos Department of Mechanical Engineering and Aeronautics, University of Patras, Rion-Patras, Greece ABSTRACT Beams with attached piezoelectric elements, vibrating near their buckling regime exhibit rich nonlinear dynamics, including bistable dynamic behaviour. Preliminary studies and reported results, suggest that under nonlinear and bistable vibrations, the electromechanical coupling and energy conversion of the piezoelectric beam is highly increased, hence, increased amounts of electric energy and electric charge are generated which can improve the dissipation and/or harvesting of strain energy from the system. Yet, the mechanisms contributing to the improved electromechanical conversion, have not been fully analysed. Consequently, the paper investigates the nonlinear dynamic electromechanical response of semi-active buckled piezoelectric beam -mass damper configurations (BPBMD), comprised of a thin buckled beam with surface bonded piezoelectric films and an attached auxiliary mass. Emphasis is given on the mechanics of nonlinear elastic energy conversion to electrical, and vice-versa. Experiments are conducted in order to characterize the electric power generated from clamped – clamped thin composite-piezoelectric beams loaded below and above the critical buckling loads and subject to variable-frequency base excitation. Subsequently, the theoretical framework and a numerical nonlinear coupled dynamic electromechanical model are presented, enabling for the analysis of the nonlinear dynamic response. The numerical models are correlated with the experimental results and the nonlinear mechanisms enhancing the electromechanical energy conversion are identified and investigated. Finally, an RL electric circuit is connected to the piezoelectric elements for semi-active vibration control and the effect of R and L values on the resultant damping and dissipated energy is investigated. |
