Cantilever Beam with Trapezoidal Cavity for Improved Energy Harvesting

This paper presents a cantilever structure as energy harvester by introducing a trapezoidal cavity to increase the amplitude of the generated voltage and the overall mechanical to electrical energy conversion efficiency. An analytical model of the proposed structure is developed using Euler-Bernoulli beam theory The effect of taper angle of the trapezoidal cavity and the neutral axis shift on the generated voltage is analyzed using analytical model and through experimentation. The generated output voltage from the energy harvester with trapezoidal cavity is compared with the beam having rectangular cavity and the beam without cavity. The generated voltage for the beam with trapezoidal cavity is 97.5% and 108% higher as compared with the beam having rectangular cavity and the beam without cavity. The characteristics of the energy harvester are evaluated through analytical model and experimentation and the results are in close agreement.