Modeling and study of magnetorheological fluid impact base frequency enhancement for a micro-piezoelectric energy generator

ABSTRACT

This paper proposes a new concept using magnetorheological fluids (MRF) as an impacting object or stopper for frequency tuning and power enhancement for a vibrating piezoelectric bimorph cantilever beam. MRF is a smart fluid that changes from a liquid state into a semi-solid state within milliseconds when a magnetic field is applied. The paper presented analytical, finite element method (FEM) and experimental results. The analytical results showed a frequency increase of 4% when the vibrating cantilever beam impacted on an activated MRF at 0.3 T magnetic field application compared to the free vibrating beam without the MRF stopper. The FEM simulation results, on the other hand, showed a 3.8% increase in frequency when the vibrating cantilever beam impacted on an activated MRF at 0.3 T magnetic field application compared to the free vibrating beam without MRF stopper. The frequency increased by 6.5% at 0.3 T magnetic field application in the experimental study. The experimental results validated the frequency enhancement of analytical results and FEM simulated results. The analytical power output results, when the vibrating cantilever beam impacted on the activated impact MRF at 0.3 T gave a maximum power output of 410$\mu W$and a load resistance of 37$k\mathbf{\Omega }.$ The FEM simulation results on the hand showed a maximum power output of 405$\mu W$and a load resistance of 37.2$k\mathbf{\Omega }$ when the vibrating cantilever impacted the activated MRF at 0.3 T magnetic field application. The experimental results demonstrated a power output of 403$\mu W$ at 0.3 T and a load resistance of 36.7$k\mathbf{\Omega }$.

KEYWORDS:

• Frequency tuning
• MRF
• magnetic field
• piezoelectric energy generator
• squeezed filmed damping