Nonlinearities give rise to secondary resonances such as superharmonic and subharmonic resonances. The superharmonic resonance can activate large-amplitude responses when the excitation frequency is a fraction of the fundamental frequency of the system. These low frequency excitations are very beneficial for ENERGY HARVESTING systems. This paper presents an analytical investigation of VIBRATIONal ENERGY harvesters with superharmonic excitation in a pietzomagnetoelastic configuration. A piezomagnetoelastic power generator is assumed to operate in the monostable and bistable modes. Nonlinear differential equations governing the oscillations of the system is solved using the method of multiple scales. System responses to the superharmonic resonance including the cantilever tip displacement and the output voltage are determined. It is found that employing the superharmonic resonance can increase the amount of harvested ENERGY in the system. The root mean square value of the output voltage is obtained for several cases in both monostable and bistable modes. The power generated in monostable and bistable modes is then compared through numerical simulations. It is observed that the bistable mode is more convenient for HARVESTING ENERGY. In addition, a Rung-Kutta numerical scheme is used to solve the differential equations. It is shown that the perturbation solution is in a close agreement with the numerical solution.

VIBRATION ENERGY HARVESTING with piezoelectric material can currently generate up to 300 microwatts per cubic centimeter, making it a viable method of powering low-power electronics. A problem in piezoelectric unimorph ENERGY HARVESTING is to generate the most power with limits in system mass. This paper studies the effect of a piezoelectric bimorph cantilever beam harvester shape on its electromechanical performance. A semi-analytical mechanical model was developed using Rayleigh–Ritz approximations for piezoelectric ENERGY harvester with tapered bimorph cantilever beam. A coupled field simulation model for the harvester is constructed using MATLAB and ABAQUS software to study the effect of varying the length and shape of the cantilever beam to the generated voltage and verification study is performed. Design optimization on the shape of the harvester is done to maximize output power. It is shown that tapered beams lead to a more uniform strain distribution across the piezoelectric material and increase the HARVESTING performance.

Large amplitude inter-well oscillations in bi-stable ENERGY harvesters have made them a proper ENERGY HARVESTING choice due to a high ENERGY generation. However, the co-existence of the chaotic attractor in these harvesters could essentially decrease their efficiency. In this work, an algorithm for detecting chaos in bistable ENERGY harvesters based on a data-gathering algorithm and estimating the largest Lyapunov exponentis investigated. First, a simple model of axially-loaded non-linear ENERGY harvesters is derived. This model is derived using the Euler-Bernoulli beam theory and the Assumed Mode method considering the Von-Karman non-linear strain-displacement equation. The harvester's numerical simulation results are used in order to test the algorithm's efficiency and accuracy in identifying the chaotic response. The results obtained show the algorithm's success in detecting chaos in such systems with a minimum possible calculation cost. The effect of noise on the algorithm's performance is also investigated, and the results obtained show an excellent robustness of the algorithm to noise. It can diagnose the harvester's chaotic or harmonic behavior with noisecontaminated data with 10% noise density. The comparison between this algorithm and the Wolf's method show a relatively less computation time (up to 80%) to detect chaos with a reasonable accuracy.

Periodic piezoelectric beams have been used for broadband VIBRATION ENERGY HARVESTING in recent years. In this paper, a periodic folded piezoelectric beam (PFPB) is introduced. The PFPB has special features that distinguish it from other periodic piezoelectric beams. The Adomian decomposition method (ADM) is used to calculate the first two band gaps and twelve natural frequencies of the PFPB. Results show that this periodic beam has wide band gaps at low frequency ranges and the band gaps are close to each other. Results also show that the PFPB can efficiently generate voltage from the localized VIBRATION ENERGY over the band gaps. The natural frequencies of the PFPB are close to each other and most of them are out of the band gaps. Therefore, the PFPB can also generate the maximum voltage over a relatively wide frequency range out of the band gaps. In order to show these features better, the voltage output of the PFPB over a wide frequency range is calculated using the ANSYS software and compared with that of a conventional piezoelectric ENERGY harvester. The ANSYS is also used to validate the analytical results and good agreement is found.

In the present paper, electrical ENERGY HARVESTING from random VIBRATIONs of an Euler-Bernoulli nano-beam with two piezoelectric layers is investigated. The beam is composed of an aluminum layer together with two piezoelectric ceramic layers (PZT 5A) serving as ENERGY HARVESTING sensors. In the proposed method, the equations governing the bimorph nano-beam will be analytically derived using classical beam theory with corresponding modification coefficients to the nano-structure applied. Then, the derived system of equations will be solved following Kantorovich method. Assumed boundary conditions for the nano-beam are as follows: a clamped end with the mass concentrated at the free end of the beam. Further, the input activation function of the system for ENERGY HARVESTING was taken as being random. Since the objective of this research is to investigate the amount of harvested ENERGY, the section on the results provides associated voltage and maximum output power curves with the bimorph nano-beam under random activation and input white noise, while also presenting the effects of characteristics and scale factor of the nano-particles on the amount of harvested ENERGY.

Electrical ENERGY regeneration and storage in a tall structure with the installed passive pendulum tuned mass and damper (PPTMD) is investigated. While the passive VIBRATION absorbing system works as an ENERGY HARVESTING device, an electrical system including an electric motor, power electronic converters, a battery charger and storage subsystem are designed in order to store the ENERGY taken from the structure VIBRATIONs which may be resulted from various external disturbances such as wind or earthquakes. The whole 76-story structure and the relevant electrical ENERGY regeneration system are modeled and simulated and the design scheme is implemented on a two-story reduced order lab structure equipped with PPTMD, the electronic circuit and the battery. A boost AC rectifier is designed and controlled to rectify the AC output voltage and is followed by a boost DC-DC converter as a battery charger for the Li-ion battery. A passivity-based controller (PC) and a sliding mode controller are designed for the rectifier and the battery charger, respectively. The simulation and the real test results demonstrate the efficient HARVESTING and storage of the ENERGY extracted from the building.

This study investigates the impact of anisotropic and isotropic piezoelectric coefficients on VIBRATIONal ENERGY HARVESTING using a piezoelectric patch integrated into plate-like structures. The research on ENERGY HARVESTING in such configurations has garnered substantial attention in recent decades, with previous studies typically assuming isotropic piezoelectric coefficients (e_31=e_32). The investigation focuses on two common boundary conditions: cantilevered composite plate (CFFF) and all-four-edges clamped (CCCC), employing a combination of analytical techniques and numerical simulations. The study presents comprehensive steady-state formulations for both the electrical and structural responses under harmonic force excitation. By comparing the voltage-frequency relationship between the analytical and numerical models, the accuracy of the analytical electroelastic model is verified. The findings highlight the potential for enhanced performance and increased output voltage in CFFF structures with an approximate rate between 5% to 8 % by minimizing the impact of the e_32 coefficient, whereas a decrease in output voltage is observed in CCCC structures. The findings emphasize that minimizing the impact of specific piezoelectric coefficients can lead to significant improvements in both performance and output voltage. This contributes to advancements in ENERGY HARVESTING technology, highlighting the importance of optimizing piezoelectric materials to achieve better efficiency in ENERGY HARVESTING applications. Additionally, the study shows that reducing the effects of e_32 in anisotropic piezoelectric harvesters can enhance ENERGY HARVESTING from the VIBRATION of a multilayer composite cantilevered plate. This research contributes valuable insights into optimizing piezoelectric ENERGY HARVESTING efficiency in plate-like structures, paving the way for advancements in ENERGY HARVESTING technology.

Global ENERGY demand will increase by 1.8% annually between 2000 and 2030. Carbon dioxide gas increases by 1.2% per year. Lack of ENERGY and air pollution are two big problems of humanity. The use of renewable ENERGY sources with the least environmental pollution is very important. Attention to the low pollution effect of HARVESTING ENERGY from the wind has led most researchers to research this type of ENERGY. Wind ENERGY is one of the renewable ENERGY sources, the new generation of bladeless wind turbines is based on a flexible structure. This article is an overview of 67 fundamental researches in this new field that are being investigated by researchers, which are based on validity and practical testing. The FSI calculations made in the articles have been filtered, the studies made are mainly to optimize the use of renewable ENERGY of the bladeless turbine and check one or two parameters. The simulated wind turbine model is without blades, almost all parameters effective in ENERGY HARVESTING in these turbines have been investigated, and an adjustment system has been used to increase the productivity hours of the wind turbine per year.

In recent years, ENERGY HARVESTING from ambient sources for use in low-powered electronics has been considered by many researchers. Wind ENERGY, solar ENERGY, water ENERGY, mechanical ENERGY from VIBRATIONs, etc are common sources of ambient ENERGY. In this paper, optimization of ENERGY HARVESTING from ambient VIBRATION using magnetic shape memory alloy is presented. To this end, a clampedclamped beam coupled with MSMA units is considered. A shock load is applied to a proof mass which is attached to the middle of the beam. As a result of beam VIBRATION a longitudinal strain is produced in the MSMA. This strain changes magnetic flux inside the coil connected to MSMA and as a result, an AC voltage is induced in the coil. To have a reversible strain in MSMA, a bias magnetic field is applied in the transverse direction of MSMA units. The Euler-Bernoulli model with von Kármán theory and a thermodynamics-based constitutive model are used to predict the non-linear strain and magnetic response.Finally, Faraday's law of induction is used to predict the output voltage. After obtaining the governing equations, a design optimization is performed to find the optimal shape and configuration of the ENERGY harvester together with the effects of proof mass and bias field.

 In the present paper, a mathematical model has been provided for a magneto-electro-elastic plate to investigate its ENERGY HARVESTING in nonlinear transverse VIBRATION. The nonlinear equations of motion of a magneto-electro-elastic plate have been used based on the Kirchhoff plate theory. These equations have been reduced to an ordinary deferential equations using Airy stress function and Galerkin Method. The equivalent electrical circuit of the structure is developed. A closed form solution has been obtained for the output power of the harvester using the method of multiple scales. The obtained results are compared with those of finite element method and a good agreement observed between the results of displacement and voltage. By introducing an analytical relation for the power as cost function, the Genetic Algorithm method is applied to optimize the best parameters of the harvester which gives the maximum power. The effect of various parameters of the harvester, such as dimension and thickness, on the power is investigated and the results are discussed.