have successfully established. On the other hand, for low powered electronics devices, harvesting energy from the ambient vibrations seems to be an ideal solution due to the definite life span and high cost for replacement of the traditional batteries. Three methods are available for vibration energy harvesting; using electrostatic devices, electromagnetic field and utilizing piezoelectric based materials. The performance of piezoelectric vibration energy harvesters for vibration-to-electricity transduction is more often than other methods, because this method has the highest power density. In other words, it can generate the highest electrical power in the same volume. Compared to other structural forms of beams, a cantilever beam can obtain the maximum deformation and strain under the same conditions. The larger deflection leads to more stress, strain, and consequently a higher output voltage and power. Therefore the vast majority of piezoelectric vibration energy harvesting devices use a cantilever beam structure (Anderson and Sexton 2006;Beeby et al. 2006;Erturk and Inman 2011;Priya and Inman 2009). A cantilever-type energy harvester has been intensively studied and a tapered cantilever has been found to be the optimum design (Matova et al. 2013;Siddiqui 2014;Muthalif and Nordin 2015), because it ensures a large constant strain (and a large power output) in the piezoelectric layer.Most of the previous research works focused on designing a linear vibration resonator, in which the maximum system performance can be achieved when the energy harvester is tuned to match its resonance frequency with the external excitation frequency. If the excitation frequency slightly shifts, the performance of the harvester will dramatically decrease. Since in the majority of practical cases, the vibration in the environment is frequency-varying or totally random with the energy distributed in a wide spectrum, how to increase the bandwidth of mechanical Abstract Power supply is a bottle-neck problem of wireless micro-sensors, especially where the replacement of batteries is impossible or inconvenient. Now piezoelectric material is being used as an additional layer in cantilever beams to harvest vibration energy for self-powered sensors. However, the geometry of a piezoelectric cantilever beam will greatly affects its vibration energy harvesting ability. This paper deduces a remarkably precise analytical formula for calculating the fundamental resonant frequency of trapezoidal V-shaped cantilevers using Rayleigh-Ritz method. This analytical formula, which is very convenient for mechanical energy harvester design based on Piezoelectric effect, is then analyzed using MATLAB as well as finite element methods and validated by ABAQUS simulation. This formula raises a new perspective that, among all the trapezoidal V-shaped cantilevers with uniform thickness, the simplest triangular tapered cantilever, can lead to maximum resonant frequency and highest sensitivity and by increasing the ratio of the trapezoidal bases, the sensitivity dec...
The small amount of power needed by microelectronic devices opens up the possibility to convert part of the vibration energy present in the environment into electrical energy, using several methods. One such method is to use piezoelectric material as an additional layer in cantilever beams to harvest vibration energy for self-powered sensors. The geometry of a piezoelectric cantilever beam will greatly affect its vibration energy harvesting ability. Tapering and changing the configuration as ways to increase the generated output power of cantilever piezoelectric energy harvesters have gained popularity in recent years. In this work vibration energy harvesting via piezoelectric resonant bimorph cantilevers is studied and new designs for obtaining optimal piezoelectric energy harvesters are suggested. This paper deduces a very precise and simple analytical formula that can be used as a rule of thumb for calculating the resonant frequency of bimorph trapezoidal V-shaped cantilevers using the Rayleigh–Ritz method. This analytical formula is then analyzed using MATLAB as well as finite element methods and validated by ABAQUS simulation. Also, mathematical derivations for the output voltage of bimorph piezoelectric energy harvesters are presented and validated by simulation and experimental results. These formulas provide a new perspective that, among all the bimorph trapezoidal V-shaped cantilever beams with uniform thickness, the bimorph triangular tapered cantilever can lead to the highest resonant frequency and therefore maximum sensitivity, and by increasing the ratio of the trapezoidal bases the sensitivity decreases. Also, the output voltage and strain distribution show that the triangular cantilever has the highest efficiency and power density.
Increasing of net energy storage (Q net) and discharge time of phase change material (t PCM) simultaneously, are important purpose in the design of solar systems. In the present paper, multiobjective (MO) based on hybrid of Particle Swarm Optimization (PSO) and multiple crossover and mutation operator is used for Pareto based optimization of solar systems. The conflicting objectives are Q net and t PCM and design variables are some geometrical parameters of solar system. The Pareto results of MO hybrid of PSO and multiple crossover and mutation operator methods are compared with that of multi-objective genetic algorithms (NSGA II). It is shown that some interesting and important relationships as useful optimal design principles involved in the performance of solar systems can be discovered.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.