Periodic solutions and frequency lock-in of vortex-induced vibration energy harvesters with nonlinear stiffness

The data are related to the amplitude jump phenomenon in the energy harvesting application. The amplitude jump may indicate the presence of multi-solution regions and unstable periodic solutions. This has not been fully investigated in the field of vortex-induced vibration energy harvesting (VIVEH). The data contain semi-analytical periodic solutions of vortex-induced vibration energy harvesters. They were obtained using the incremental harmonic equilibrium method, and their stability was determined using Floquet theory. It was found that VIVEH with linear stiffness and those with third-order nonlinear stiffness have four saddle junction bifurcation points and two multi-solution ranges, which leads to the occurrence of amplitude jumps. The hardening effect can shift the frequency lock regions to higher wind speeds, thus increasing the aerodynamic forces and realizing wide wind speed bands and high voltage outputs. Wind tunnel experiments verify the accuracy of theoretical calculations, the occurrence of amplitude jump phenomena, and the existence of multi-solution ranges. In the VIVEH tests with nonlinear stiffness, a maximum voltage of 9.87 V and a synchronization frequency range of 2.27–5.36 m/s were achieved.

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