Nonlinear Modal Interactions to Improve the Broadband Transduction of Vibratory Energy Harvesters

This article exploits nonlinear modal interactions, namely, a two-to-one internal resonance energy pump to improve the steady-state bandwidth of vibratory energy harvesters. To demonstrate the enhanced performance, an L-shaped cantilevered structure laminated with a piezoelectric patch and augmented with frequency tuning magnets is considered. The magnets serve to adjust the first two modal frequencies of the structure such that the second modal frequency is twice that of the first mode activating a nonlinear energy transfer mechanism. The structure is then subjected to a harmonic excitation with a frequency close to the first modal frequency of the structure. The voltage frequency-response curves are generated for different excitation levels, illustrating an improved bandwidth and output voltage over a case involving no nonlinearly-interacting modes.