Optimal strain-deflection analyses of a wedge edged beam for enhanced vibration energy scavenging in patch-like harvester.

Recently, non-prismatic beams have been considered as perfect substitutes to replace uniform cantilever beam structures in harvester design. This is due to their tendencies to provide uniform strain distribution, which enhances piezoelectric (PZT) charge generation when coupled with the beams. As the voltage produced by the PZT depends largely on the geometrical shape of the substrate, thus there is need for formulations to analyze the behavior of the shim prior to practical implementation. In this paper, analytical and finite element models were developed to study deflection and strain distribution of a non-prismatic beam termed, wedge edged cantilever (WEC) for patch-like harvester application. The analyses offer possibility for maximum utilization of strain location along the beam span for efficient harvester design. Vibration energy harvesting characteristics of the WEC beam with partially covered PZT material forming three configurations namely: Config1, Config2 and Config3 were studied. Both numerical and experimental results show that Confg3 with macro fiber composite (MFC) as the PZT material covering the determined optimal strain position yielded 2 to 3 times more peak output voltage than Config1 and Config2 with the MFC bonded at non-optimal positions. [ABSTRACT FROM AUTHOR]