Non-linear Dynamics of Flexural Disc Transducers

Flexural transducers are well suited for power emission in fluids, thanks to their low mechanical impedance. Their performance is nevertheless compromised by the occurrence of non-linearities stemming from high-deflection andlor high electric field. This experimental work catalogs typical alterations of the transducers' dynamics resulting specifically from high electrical field non-linearities. We use depoled transducers to model efficient ones under high electrical field conditions. The depoled transducer are not subject to purely structural non-linearities as the d flection remains low but still exhibit electric-fieldrelated non-linearities. Results show that the response of the transducers can u dergo major qualitative changes as the strength of the excitation increases : hysteresis cycles, super-harmonic excitation sharp saturation of the displacement, non periodic response of the transducer to an AC forcing tension and unstable transfer of energy between the spectral components of the displacement signal. Practical implications include transducers' design, model parameter fitting and second harmonic generation.