A Shear-Regulated Piezoelectric Vibration Energy Harvester

The unit described in this study is a shear-regulated piezoelectric vibration harvester intended for powering wireless condition-monitoring sensors on rotating machinery. Its operating principle is that a cantilevered piezoelectric beam with a proof mass converts machine vibration to charge, and a shear-regulated mechanical stop caps beam strain at the value set by the shear limit adopted for the design. The design is computed from stated assumptions throughout; it is simulated, not measured, and no prototype results are reported. The headline result is a average harvested power of 9.06 mW, obtained with base acceleration of 2.5 m/s^2 with a computed efficiency or performance coefficient of 8.5 per cent where that measure applies, for a unit of mass 0.12 kg whose characteristic scale is a proof mass of 0.05 kg. A parameter sweep reported in the Results section shows how the output moves when the principal variable is changed, and the density of the working material, 7.5e+03 kg per cubic metre, sits about 54.1 orders of magnitude below the neutron-carrier density bound of 9.72e+57 kg per cubic metre, so the bound enters this design as a sizing ceiling and a margin statement rather than as an operating condition. The limitations are stated plainly: output falls sharply away from resonance and with the square of acceleration, so most real mounting points deliver far less than the design point. Status: SIMULATED, NOT MEASURED.