Extension of cross-well bandwidths for bistable piezoelectric plate oscillators

Snap-through dynamics between the two potential wells of bistable oscillators are exhibited over a wide frequency range which narrows with decreasing harmonic excitation amplitudes until disappearing at a critical forcing level. However, for efficient conversion from vibrational to electrical energy in harvesting applications, the bistable oscillator must retain its favorable broadband cross-well response while the input excitation is minimized. To maintain effectiveness at low forcing levels, an actuation approach is proposed where external perturbations are used to extend the oscillator’s cross-well bandwidths by switching from co-existing low to high energy attractors. By utilizing Macro Fiber Composites (MFC) in a [ 0 MFC / 90 MFC ] T bistable piezoelectric laminate, the application of rectangular voltage pulse signals are cycled through different response phases to continuously alter the basins of attraction until the desired cross-well orbit is sustained at each frequency. The pulse magnitude is where the system exhibits limit point behavior and the resulting snap through actuation mechanism brings consistency between perturbation trials. A multi degree of freedom electromechanical model that captures the stable shapes and cross-well dynamics and finite element analysis in Abaqus/Standard demonstrate the efficacy of the perturbation method. The model is then employed to significantly increase the bandwidths inducing cross-well oscillations.