Efficient Nonlinear Response Determination of an Array of OWC Energy Harvesters

2020 ◽  
Author(s):  
Giovanni Malara ◽  
Pol D. Spanos
Keyword(s):  
Electrical Energy ◽  
Approximate Solutions ◽  
Wave Radiation ◽  
Equivalent Linearization ◽  
Sea Waves ◽  
Energy Harvesters ◽  
Array Configuration ◽  
Water Columns ◽  
Direct Numerical Integration ◽  
Integration Data

Abstract Oscillating Water Columns (OWC) are utilized for producing electrical energy from sea waves by exploiting the oscillation of a water column located under an air chamber for producing an air flow driving an air turbine connected to an electrical generator. The array configuration is considered in several engineering applications, where the OWCs are embedded in coastal infrastructures, such as vertical breakwaters. In this context, the water columns are likely to be placed nearby. Thus, interactions among chambers occur because of wave radiation phenomena. This article describes a nonlinear model governing the dynamics of an OWC array embedded in a vertical breakwater. The differential equations include effects associated with hydrodynamic memory and isentropic thermodynamics, which prohibit the derivation of an exact solution giving the OWC array response. Thus, the article develops approximate solutions determined by relying on the concept of equivalent linearization, which is applied under the assumption of both deterministic, and stochastic excitations. Juxtaposition of the approximate approach results with relevant direct numerical integration data confirm its reliability and efficiency.

Integration Algorithm for Covariance Nonstationary Dynamic Analysis of SDOF Systems Using Equivalent Stochastic Linearization

2015 ◽  
Vol 15 (02) ◽  
pp. 1450044 ◽  
Author(s):  
Giuseppe Carlo Marano ◽  
Giuseppe Acciani ◽  
Alessandra Fiore ◽  
Angela Abrescia
Keyword(s):  
Computational Cost ◽  
Lyapunov Equation ◽  
Approximate Solutions ◽  
Nonstationary Process ◽  
Equivalent Linearization ◽  
Sea Waves ◽  
System Matrix ◽  
Integration Algorithm ◽  
Stochastic Linearization ◽  
Linearized System

Random vibration theory is the natural way to deal with some dynamic actions whose nature is deeply random, such as wind, earthquakes or sea waves. Moreover only in a few cases exact solutions are available, so that approximate solutions are usually adopted: Stochastic equivalent linearization is one of the widely used. Its application needs specific numerical techniques, whose complexity is greater in nonstationary cases than in stationary ones and that are usually approached in time domain instead of frequency domain. In this paper, an iterative integration algorithm is proposed in order to solve this problem for single-degree-of-freedom (SDOF) oscillators, using the evolutive Lyapunov equation for nonlinear mechanical linearized system by stochastic linearization technique. It updates linearized system matrix coefficients step by step, by an iterative procedure based on a predictor–corrector technique. The proposed algorithm is described and applied to an hysteretic Bouc–Wen SDOF system excited by a modulated filtered white noise nonstationary process. The accuracy and computational cost are analyzed showing the efficiency of the proposed integrating procedure.

scholarly journals The Use of Piezoceramics As Electrical Energy Harvesters Within Instrumented Knee Implant During Walking

2011 ◽  
Vol 16 (5) ◽  
pp. 799-807 ◽  
Author(s):  
Shaban Almouahed ◽  
Manuel Gouriou ◽  
Chafiaa Hamitouche ◽  
Eric Stindel ◽  
Christian Roux
Keyword(s):  
Electrical Energy ◽  
Energy Harvesters

The use of sea waves for generation of electrical energy and Hydrogen

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
Vincenzo Di Dio ◽  
Vincenzo Franzitta ◽  
Francesco Muzio ◽  
Gianluca Scaccianoce ◽  
Marco Trapanese
Keyword(s):  
Electrical Energy ◽  
Sea Waves

Tadpole: A Design Problem in the Mechanics of the Use of Sea Wave Energy

1996 ◽  
Vol 210 (4) ◽  
pp. 273-277 ◽  
Author(s):  
M J French
Keyword(s):  
Wave Energy ◽  
Special Interest ◽  
Reaction Force ◽  
Electrical Energy ◽  
Wave Forces ◽  
Sea Waves ◽  
Small Machine ◽  
Clear Insight ◽  
Insight Into ◽  
Sea Wave

A study is made of a device for obtaining electrical energy from sea waves, in which the problem of providing a reaction against the wave forces is met by a combination of a pendulum and gyroscopes. The mechanics is developed in a logical manner which gives a clear insight into the function, the pendulum providing the reaction force, which leaves an unbalanced moment to be countered by the gyroscopes, which also constitute the power take-off. The result is a relatively small machine with no external moving parts. The treatment requires no understanding of wave hydrodynamics. It is felt this paper may be of special interest as a design study, in which the relation between the mechanics and the development of the concept is peculiarly cogent.

Resonant Frequency Tuning Strategies for Vibration-Based Energy Harvesters

2017 ◽  
Author(s):  
Lin Dong ◽  
Frank T. Fisher
Keyword(s):  
Energy Harvesting ◽  
Resonant Frequency ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Electrical Energy ◽  
Mechanical Stretch ◽  
Applied Bias Voltage ◽  
Energy Harvesters ◽  
Frequency Matching ◽  
Low Levels

Vibration-based energy harvesting has been widely investigated to as a means to generate low levels of electrical energy for applications such as wireless sensor networks. However, due to the fact that vibration from the environment is typically random and varies with different magnitudes and frequencies, it is a challenge to implement frequency matching in order to maximize the power output of the energy harvester with a wider frequency bandwidth for applications where there is a time-dependent, varying source frequency. Possible solutions of frequency matching include widening the bandwidth of the energy harvesters themselves in order to implement frequency matching and to perform resonance-based tuning approach, the latter of which shows the most promise to implement a frequency matching design. Here three tuning strategies are discussed. First a two-dimensional resonant frequency tuning technique for the cantilever-geometry energy harvesting device which extended previous 1D tuning approaches was developed. This 2D approach could be used in applications where space constraints impact the available design space of the energy harvester. In addition, two novel resonant frequency tuning approaches (tuning via mechanical stretch and tuning via applied bias voltage, respectively) for electroactive polymer (EAP) membrane-based geometry energy harvesters was proposed, such that the resulting changes in membrane tension were used to tune the device for applications targeting variable ambient frequency environments.

Stress Analysis of Smart Beam Energy Harvesters

2016 ◽  
Author(s):  
Nathan S. Hosking ◽  
Zahra Sotoudeh
Keyword(s):  
Smart Materials ◽  
Mechanical Energy ◽  
Strain Analysis ◽  
Electrical Energy ◽  
Structural Dynamic ◽  
Energy Harvesters ◽  
Beam Equations ◽  
Variational Asymptotic ◽  
Strain Components ◽  
Smart Beam

In this paper, we study fully coupled electromagnetic-elastic behaviors present in the structures of smart beams using variational asymptotic beam sections and geometrically exact fully intrinsic beam equations combined in a consistent theory. We present results for smart beams under various oscillatory loads in both the axial and transverse directions and calculate the corresponding deformations. Recovery equations are employed to construct the full 3D stress and strain components in order to complete a full stress / strain analysis. Smart materials change mechanical energy to electrical energy; therefore, changing the structural dynamic behavior of the structure and its stiffness matrix.

A Novel Multi-Directional Nonlinear Piezoelectric Energy Harvester Coupled With Nonlinear Conditioning Circuits

2015 ◽  
Author(s):  
Zhengbao Yang ◽  
Jean Zu
Keyword(s):  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Electrical Energy ◽  
Elastic Rods ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
High Power Output ◽  
Transduction Mechanisms ◽  
Self Powered ◽  
Aluminum Plates

Energy harvesting from vibrations has become, in recent years, a recurring target of a quantity of research to achieve self-powered operation of low-power electronic devices. However, most of energy harvesters developed to date, regardless of different transduction mechanisms and various structures, are designed to capture vibration energy from single predetermined direction. To overcome the problem of the unidirectional sensitivity, we proposed a novel multi-directional nonlinear energy harvester using piezoelectric materials. The harvester consists of a flexural center (one PZT plate sandwiched by two bow-shaped aluminum plates) and a pair of elastic rods. Base vibration is amplified and transferred to the flexural center by the elastic rods and then converted to electrical energy via the piezoelectric effect. A prototype was fabricated and experimentally compared with traditional cantilevered piezoelectric energy harvester. Following that, a nonlinear conditioning circuit (self-powered SSHI) was analyzed and adopted to improve the performance. Experimental results shows that the proposed energy harvester has the capability of generating power constantly when the excitation direction is changed in 360. It also exhibits a wide frequency bandwidth and a high power output which is further improved by the nonlinear circuit.

Investigation of Vibration Energy Harvesting Using Two Cantilevers With Random Input

2017 ◽  
Author(s):  
Wei Yang ◽  
Panagiotis Alevras ◽  
Shahrzad Towfighian
Keyword(s):  
Mechanical Energy ◽  
Duffing Oscillator ◽  
Electrical Energy ◽  
Potential Energy Function ◽  
Excitation Level ◽  
Vibration Energy ◽  
Random Input ◽  
Vibration Energy Harvesting ◽  
Energy Harvesters ◽  
Low Performance

There is a growing interest to convert ambient mechanical energy to electrical energy by vibration energy harvesters. Realistic vibrations are random and spread over a large frequency range. Most energy harvesters are linear with narrow frequency bandwidth and show low performance, which led to creation of nonlinear harvesters that have larger bandwidth. This article presents a simulation study of a nonlinear energy harvester that contains two cantilever beams coupled by magnetic force. One of the cantilever beam is covered partially by piezoelectric material, while the other beam is normal to the first one and is used to create a variable potential energy function. The variable double-well potential function enables optimum conversion of the kinetic energy and thus larger output. The system is modeled by coupled Duffing oscillator equations. To represent the ambient vibrations, the response to Gaussian random input signal (generated by Shinozuka formula) is studied using power spectral density. The effects of different parameters on the system are also investigated. The results show that the double cantilever harvester has a threshold distance, where the harvester can perform optimally regardless of the excitation level. This observation is opposite to that of the conventional fixed magnet cantilever system where the optimal distance varies with the excitation level. Results of this study can be used to enhance energy efficiency of vibration energy harvesters.

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