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A Parametric Resonator With Low Threshold Excitation For Vibration Energy Harvesting, Shahrzad Towfighian, Wei Yang
A Parametric Resonator With Low Threshold Excitation For Vibration Energy Harvesting, Shahrzad Towfighian, Wei Yang
Mechanical Engineering Faculty Scholarship
A parametric resonator for vibration energy harvesting is presented. Despite large responses from parametric resonance, two major drawbacks of parametric resonance harvesters are the high threshold excitation and narrow bandwidth. We addressed these two shortcomings by adding magnetic nonlinearity to the system. The proposed vibration energy harvester consists of two piezoelectric cantilevers beams, each with a magnetic tip. By controlling the distance between the two magnets, the threshold excitation level needed to trigger the parametric resonance decreases. Combining the softening and hardening behavior of the two magnetically coupled beams increases the frequency bandwidth. In addition, the amplitude of the response …
A Parametric Electrostatic Resonator Using Repulsive Force, Mark Pallay, Shahrzad Towfighian
A Parametric Electrostatic Resonator Using Repulsive Force, Mark Pallay, Shahrzad Towfighian
Mechanical Engineering Faculty Scholarship
In this paper, parametric excitation of a repulsive force electrostatic resonator is studied. A theoretical model is developed and validated by experimental data. A correspondence of the model to Mathieu's Equation is made to prove the existence and location of parametric resonance. The repulsive force creates a combined response that shows parametric and subharmonic resonance when driven at twice its natural frequency. The resonator can achieve large amplitudes of almost 24 μm and can remain dynamically stable while tapping on the electrode. Because the pull-in instability is eliminated, the beam bounces off after impact instead of sticking to the electrode. …