Energy harvesting and evaluation of a novel piezoelectric bridge transducer

A novel bridge transducer based on the cymbal design has been developed for energy harvesting from impact loading by vehicle-induced deformations on pavement. The bridge transducer consists of a 2 mm thick 32 x 32 mm square soft PZT ceramic and hardened steel end caps. A unique electrode design enables the PZT to be poled along its length, effectively utilizing d 33 mode for enhanced energy generation. The effective d(33), of d(33)(eff) of a bridge transducer is 19,000 pC/N and the effective piezoelectric voltage coefficient, g(33)(eff), is 2150 x 10(-3) Vm/N. When compared to the conventional cymbal transducer design, horizontal poling increases energy and voltage considerably. Each loading at 600 lbs generates 0.83 mJ of energy from the prototype transducer module with 64 transducers in parallel. Loading under simulated traffic conditions at 500 lb and 5 Hz generates 2.1 mW at a resistive load of 330 kOhm. The reliability and cycles to failure of the transducer design is studied and the transducers are evaluated after 50,000 loading cycles. Inconsistency in the epoxy layer thickness has been identified as the cause of premature failure. (C) 2018 Published by Elsevier B.V.