A novel 3D folded zigzag piezoelectric energy harvester; modeling and experiments

Abstract

Cantilever geometries have been widely used for vibration energy harvesting applications due to their simple geometries, frequency tune-ability, and obtainability of their closed form analytical solutions. Recent studies have focused on overcoming some of the drawbacks for this configuration, which include low power density and natural frequencies much higher than those available in the environment. Some investigate two-dimensional geometries, such as a zigzag shaped design, meandering and elephant design. The previously researched designs offer a higher flexibility that allows for much smaller fundamental natural frequencies and improved power densities. The presented work extends this idea by offering a three-dimensional (3D) design called ‘folded zigzag’ that provides much better flexibility than the aforementioned units, and aids significantly with natural frequency requirements despite a small footprint. Compared to a planar design the proposed 3D design of the same footprint offers a much lower resonating frequency with increased flexibility, and also results in improved strain node pattern by avoiding torsion in the fundamental modes of its operation. This significantly eases the fabrication as avoids the charge cancellations when mounting continuous electrodes. Power densities for the proposed design are presented and compared to the flex geometry, a planar symmetric design, and experimental validations are made for the folded unit. The results show that the new design can produce higher power density per layer compared to the planar symmetric zigzag (flex geometry). This comparison is made while keeping all the system parameters the same for both units such as the footprint, dimensions, and tip mass per layer. Additionally, the simulation results show that increasing the number of stories or the distance between the consecutive stories for this design can help significantly with the reduction in the number of strain nodes in the fundamental modes. This as well helps with the electrode geometry due to avoiding the charge cancellation. Finally, it is shown that the presence of the strain nodes can be avoided for smaller footprints compared to the planar symmetric zigzag before the torsional modes become dominant.

Effects of Strain Node on the Actuation Performance of Multilayer Cantilevered Piezoactuator with Segmented Electrodes

“…In order to investigate the relationship between the tip deflection and the beam length [18], the values of tip deflection of the MCPA were obtained when L � 0-2.0 mm and V � 1-5 V. e theoretical/simulation results of the L-tip deflection curves of MCPA-C and MCPA-S at first and second mode are given in Figures 9 and 10. Under different constant voltages, as the beam length L increases from 0 to 2 mm, the tip deflections at the first and second modes increase nonlinearly, which is consistent with [22].…”

“…In this paper, by optimizing the structure of segmented electrodes, a MCPA with segmented electrodes based on the strain nodes is designed to improve the actuation performance [18]. e strain nodes are determined by the normalized deflection and strain distribution [14].…”

Performance Evaluation of Novel Piezoelectric Cantilever Beam Structure for Energy Harvesting

“…Contantinou et al developed a 3D printed electromagnetic vibration energy harvester generating power of 2.9 MW at a bandwidth of 4.5 Hz, which is comparable to existing in-plane systems [6]. Similarly, Bath et al suggested a 3-dimensional folded zig-zag geometry, with increased flexibility with higher power density [7]. Cha et al reported calculation of power transferred to varied load resistances under repeated knee motion and gloves using an electromechanical model of piezoelectric harvesting [8,9].…”

Expected lifetime of fibrous nanogenerator exposed to cyclic compressive pressure

“…Using additives and fillers to improve the electroactive properties of PVDF, optimizing the fabrication process parameters, changing the structure and configuration of the harvester, and identifying the optimal operating mode are some topics of such studies [30][31][32][33][34]. In addition to the mentioned issues, some researchers tried to use 3 D printing to fabricate a PVDF electroactive meshes as a ready-to-use products [35][36][37][38]. Despite the wide range of studies on PVDF nanofibers, limited researches have been done on their performance over the usage time.…”