Dynamic response of auxetic and functionally graded piezoelectric energy harvester using PVDF polymer

Abstract

Piezoelectric energy harvesting has garnered greater interest in the past two decades than other vibration energy harvesting techniques for wireless power sensors and portable electronics. This work initially considers a bimorph cantilever with a solid substrate for analysis, keeping the first eigenfrequency below 100 Hz for environmental energy harvesting. Polyvinylidene fluoride (PVDF)-polymer is used as piezoelectric material due to its higher flexibility and brass is used as a substrate. The cantilever beam of length (L), width (B), the thickness of the substrate (ts) and piezoelectric layer (tp) are 50, 12.5, 0.14, and 0.25 mm, respectively, considered for analysis and having an eigenfrequency of 44 Hz. Further, an auxetic substrate (elliptical structure) and functionally graded piezoelectric material are incorporated to enhance power output. The maximum power is obtained as 8.33, 8.97 and 3.3 mW for conventional (solid) substrate, auxetic substrate and functionally graded piezoelectric layer under 3.5g excitation. The auxetic design has enhanced power output, whereas functionally graded materials have better surface bonding. © 2023 Taylor & Francis Group, LLC.