A Mathematical and Simulation Study of Lanthanum-Modified PZT for Enhanced Serendipity Shaped Cantilever Piezoelectric Energy Harvester

Piezoelectric energy harvesting is widely explored for powering low-frequency structural-health-monitoring (SHM) systems. The effect of lanthanum (La) mixing on the performance of PZT-5A and PZT-5J, particularly in nonuniform cantilever geometries, remains insufficiently explored. In this work, the effect of La concentrations of 1.12, 2.24, and 3.36 percentage of weights in a serendipity shaped cantilever piezoelectric energy harvester were examined using copper, silicon, and structural-steel substrates with nickel electrodes. A reduced single-degree-of-freedom electromechanical model was developed to interpret the simulated behaviour. Results show that La mixing enhances output voltage and harvested power across all configurations. The highest performance was obtained for PZT-5A with structural steel and 3.36 % La, yielding 15.47 V and 9.98 mW at 32 Hz. For PZT-5J with 3.36 % La on copper, 13.466 V and 7.55 mW were achieved. Analytical calculations predicted a maximum power of 9.319 mW at an optimal load of 50 kΩ. Capacitance of 96.2 nF for PZT-5A and 107.5 nF for PZT-5J corresponded to electrical reactance near 51.7 kΩ and 46.3 kΩ. An extraction efficiency of 26.1 % under 2 g excitation was estimated. Overall, La mixing improved the output by 12–13 %, providing an effective design pathway for enhanced PZT-based energy harvesters for low-frequency SHM applications.