The Experts below are selected from a list of 56505 Experts worldwide ranked by ideXlab platform
Daniel J. Inman - One of the best experts on this subject based on the ideXlab platform.
-
Harmonic balance analysis of nonlinear tristable energy Harvesters for performance enhancement
Journal of Sound and Vibration, 2016Co-Authors: Shengxi Zhou, Junyi Cao, Jing Lin, Daniel J. Inman, Dan LiAbstract:Nonlinear energy Harvesters are very sensitive to ambient vibrations. If the excitation level is too low, their large-amplitude oscillations for high-energy voltage output cannot be obtained. A nonlinear tristable energy harvester has been previously proposed to achieve more effective broadband energy harvesting for low-level excitations. However, the sensitivity of its dynamic characteristics to the system parameters remains uninvestigated. Therefore, this paper theoretically analyzes the influence of the external load, the external excitation, the internal system parameters and the equilibrium positions on the dynamic responses of nonlinear tristable energy Harvesters by using the harmonic balance method. In addition, numerical acceleration excitation thresholds and basins of attraction are provided to investigate the potential for energy harvesting performance enhancement using the suitable equilibrium positions, appropriate initial conditions or external disturbances, due to high-energy interwell oscillations in the multi-solution ranges. More importantly, experimental voltage responses of a given tristable energy harvester versus the external excitation frequency and amplitude verify the existence of experimental multi-solution ranges and the effectiveness of the theoretical analysis. It is also revealed that achieving high-energy interwell oscillations in the multi-solution ranges of tristable energy Harvesters will be feasible for improving energy harvesting from low-level ambient excitations.
-
optimum resistive loads for vibration based electromagnetic energy Harvesters with a stiffening nonlinearity
Journal of Intelligent Material Systems and Structures, 2014Co-Authors: Andrea Cammarano, Steve G Burrow, Simon A Neild, D J Wagg, Daniel J. InmanAbstract:The exploitation of nonlinear behavior in vibration-based energy Harvesters has received much attention over the last decade. One key motivation is that the presence of nonlinearities can potentially increase the bandwidth over which the excitation is amplified and therefore the efficiency of the device. In the literature, references to resonating energy Harvesters featuring nonlinear oscillators are common. In the majority of the reported studies, the harvester powers purely resistive loads. Given the complex behavior of nonlinear energy Harvesters, it is difficult to identify the optimum load for this kind of device. In this paper the aim is to find the optimal load for a nonlinear energy harvester in the case of purely resistive loads. This work considers the analysis of a nonlinear energy harvester with hardening compliance and electromagnetic transduction under the assumption of negligible inductance. It also introduces a methodology based on numerical continuation which can be used to find the optimum load for a fixed sinusoidal excitation.
-
Parametric study of zigzag microstructure for vibrational energy harvesting
Journal of Microelectromechanical Systems, 2012Co-Authors: M. Amin Karami, Daniel J. InmanAbstract:A comprehensive parametric study is presented on the vibration and the energy harvesting performance of a low-frequency zigzag energy harvester. The zigzag microelectromechanical systems (MEMS) vibrational energy Harvesters have low natural frequencies which match the low-frequency range of ambient vibrations. The Harvesters can, therefore, be designed to resonate with ambient excitation. The power produced by energy Harvesters at resonance is orders of magnitude larger than off resonance power. The paper aims at providing an easy-to-use, comprehensive tool for designing the Harvesters for different applications. The two key characteristics of the vibrational energy Harvesters are their resonance frequency and their power transfer function. We formulate both vibrations and power production of the zigzag MEMS Harvesters in nondimensional equations. The paper advances the state of the art in MEMS energy harvesting research area by identifying the dimensionless parameters governing mechanical vibrations and energy generation. We also investigate how the resonant frequency and the maximum power vary with each of the corresponding dimensionless parameters. The graphs summarize the parametric studies and provide sufficient tools for design of zigzag Harvesters. The natural frequencies are related to six dimensionless variables, and the power transfer functions depend on 12 dimensionless parameters.
-
Inertial Energy Harvester for Monitoring Wind Turbine Blades
Proc. IWSHM 2011, 2011Co-Authors: Bryan Joyce, Justin Farmer, Daniel J. InmanAbstract:In order to operate a structural health monitoring (SHM) device for a wind turbine blade, one needs to use a slip ring to siphon power from the turbine’s generator or use a power source inside the blade. An energy harvester mounted inside the turbine blade capturing energy from the blades rotation would be a great solution for powering a SHM device for a long period of time. The low rotation speeds (between 5 and 20 RPM for the many large scale turbines) make it challenging to harvest sufficient power. Previous research into energy Harvesters in rotating environments (e.g. automotive wheels and propellers on large ships) has examined much higher rotation speeds (in the range of 100 to 1000 RPM). At the rotation speeds of large wind turbines, these Harvesters have either not been tested or they produced only a few hundred microwatts. This paper discusses the modeling and experimental validation of an inertial energy harvester for use in low speed wind turbines to power a SHM device. The harvester consists of a magnet placed inside a slider tube and a coil mounted on the outside of the tube. The harvester assembly is then mounted radially inside the turbine blade. As the turbine rotates, the magnet slides along the tube and through the coil. The moving magnet induces a voltage across the terminals of the coil. This voltage can be stored in a capacitor or rechargeable battery which would in turn supply power to a health monitoring system. This paper will outline the modeling of the harvester, validation of an electromechanical coupling model, and testing a prototype harvester on a rotating apparatus.
-
A Distributed Parameter Electromechanical Model for Cantilevered Piezoelectric Energy Harvesters
Journal of Vibration and Acoustics, 2008Co-Authors: Alper Erturk, Daniel J. InmanAbstract:Cantilevered beams with piezoceramic layers have been frequently used as piezoelectric vibration energy Harvesters in the past five years. The literature includes several single degree-of-freedom models, a few approximate distributed parameter models and even some incorrect approaches for predicting the electromechanical behavior of these Harvesters. In this paper, we present the exact analytical solution of a cantilevered piezoelectric energy harvester with Euler-Bernoulli beam assumptions. The excitation of the harvester is assumed to be due to its base motion in the form of translation in the transverse direction with small rotation, and it is not restricted to be harmonic in time. The resulting expressions for the coupled mechanical response and the electrical outputs are then reduced for the particular case of harmonic behavior in time and closed-form exact expressions are obtained. Simple expressions for the coupled mechanical response, voltage, current, and power outputs are also presented for excitations around the modal frequencies. Finally, the model proposed is used in a parametric case study for a uni-morph harvester, and important characteristics of the coupled distributed parameter system, such as short circuit and open circuit behaviors, are investigated in detail. Modal electromechanical coupling and dependence of the electrical outputs on the locations of the electrodes are also discussed with examples
Haiqiao Wei - One of the best experts on this subject based on the ideXlab platform.
-
Similarity and duality of electromagnetic and piezoelectric vibration energy Harvesters
Mechanical Systems and Signal Processing, 2015Co-Authors: Xu Wang, S. Watkins, Xingyu Liang, Sabu John, Han Xiao, Xinghuo Yu, Haiqiao WeiAbstract:A frequency analysis has been conducted to study vibration energy harvesting performance and characteristics of a single degree of freedom vibration energy harvester connected to a single load resistor based on the Laplace transfer method and physical models of a voltage source. The performance and characteristics of electromagnetic and piezoelectric Harvesters have been analysed and compared. The main research outcome is the disclosure of similarity and duality of electromagnetic and piezoelectric Harvesters for both the energy harvesting efficiency and the normalised resonant harvested power using only two dimensionless characteristic parameters: the normalised resistance and the normalised force factor. The dimensionless resonant harvested power and energy harvesting efficiency analysis allows for a parameter study and optimization of the ambient vibration energy Harvesters from macro-to nano-scales and for evaluation of the vibration energy harvester performance regardless of the size and type.
-
A study of electromagnetic vibration energy Harvesters with different interface circuits
Mechanical Systems and Signal Processing, 2015Co-Authors: Xu Wang, Xingyu Liang, Haiqiao WeiAbstract:A dimensionless analysis of piezoelectric vibration energy harvester was conducted in the previous work where the harvested power and energy harvesting efficiency were normalised and determined from two non-dimensional variables of resistance and force factor. This paper has developed a dimensionless analysis of an electromagnetic vibration energy harvester where the harvested power and energy harvesting efficiency are normalised and determined from two similar non-dimensional variables of resistance and equivalent force factor. The harvested power and efficiency are compared for the electromagnetic harvester with different interface circuits. The aim is to disclose some similarity and limitations of the piezoelectric and electromagnetic Harvesters in a dimensionless scale.
Steve Beeby - One of the best experts on this subject based on the ideXlab platform.
-
Scaling effects for piezoelectric energy Harvesters
Smart Sensors Actuators and MEMS VII; and Cyber Physical Systems, 2015Co-Authors: Steve BeebyAbstract:This paper presents a fundamental investigation into scaling effects for the mechanical properties and electrical output power of piezoelectric vibration energy Harvesters. The mechanical properties investigated in this paper include resonant frequency of the harvester and its frequency tunability, which is essential for the harvester to operate efficiently under broadband excitations. Electrical output power studied includes cases when the harvester is excited under both constant vibration acceleration and constant vibration amplitude. The energy harvester analysed in this paper is based on a cantilever structure, which is typical of most vibration energy Harvesters. Both detailed mathematical derivation and simulation are presented. Furthermore, various piezoelectric materials used in MEMS and non-MEMS Harvesters are also considered in the scaling analysis
-
Energy Harvesting Devices
Resonant MEMS: Principles Modeling Implementation and Applications, 2015Co-Authors: Steve BeebyAbstract:© 2015 Wiley-VCH Verlag GmbH & Co. KGaA. This chapter is concerned with mechanical energy harvesting devices designed to convert ambient kinetic energy into electrical energy. It discusses the application of resonant mechanical systems in energy harvesting and explains the implications of microelectro mechanical system (MEMS) technology. The chapter provides basic formulas that characterize the devices and discusses strategies for maximizing the kinetic energy that can be captured by the harvester from different forms of ambient energy. MEMS energy Harvesters have been demonstrated and research continues to improve performance and address issues such as operating frequencies. It is clear that either electrostatic or piezoelectric transduction can scale down in size and be used in MEMS Harvesters. Developing a technique to increase the inertial mass by a factor of 2 may potentially double the output power of the harvester and such a step change in performance is unlikely to be realized by optimizing a transduction method or associated material.
-
Screen printed piezoelectric films for energy harvesting
Advances in Applied Ceramics, 2013Co-Authors: D. Zhu, P Glenne-jones, A Almusallam, Russel Torah, John Tudor, N. White, N. Harris, Steve BeebyAbstract:This paper describes the development of screen printed vibration energy Harvesters developed at the University of Southampton. The mark 1 harvester developed very low levels of power (2 mW) due to the poor piezoelectric properties of the printed film. Properties were improved by blending particle sizes and optimising firing and poling conditions. The new piezoelectric paste was applied to Harvesters developed for the EU funded project TRIADE. Power outputs have improved to 240 mW from an excitation vibration of 0.29g rms (g59.8 m s 22 ) at 67 Hz. Multilayer structures also demonstrate further improvements, and the harvester has been demonstrated powering an autonomous wireless sensor system for condition monitoring. © 2013 Institute of Materials, Minerals and Mining.
-
Vibration energy harvesting using the Halbach array
Smart Materials and Structures, 2012Co-Authors: D. Zhu, Steve Beeby, John Tudor, Nick HarrisAbstract:This paper studies the feasibility of vibration energy harvesting\nusing a Halbach array. A Halbach array is a specific arrangement\nof permanent magnets that concentrates the magnetic field on one\nside of the array while cancelling the field to almost zero on the\nother side. This arrangement can improve electromagnetic coupling\nin a limited space. The Halbach array offers an advantage over conventional\nlayouts of magnets in terms of its concentrated magnetic field and\nlow-profile structure, which helps improve the output power of electromagnetic\nenergy Harvesters while minimizing their size. Another benefit of\nthe Halbach array is that due to the existence of an almost-zero\nmagnetic field zone, electronic components can be placed close to\nthe energy harvester without any chance of interference, which can\npotentially reduce the overall size of a self-powered device. The\nfirst reported example of a low-profile, planar electromagnetic vibration\nenergy harvester utilizing a Halbach array was built and tested.\nResults were compared to ones for energy Harvesters with conventional\nmagnet layouts. By comparison, it is concluded that although energy\nHarvesters with a Halbach array can have higher magnetic field density,\na higher output power requires careful design in order to achieve\nthe maximum magnetic flux gradient.
-
a Planar Electromagnetic Vibration Energy Harvester With a Halbach Array
The 11th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications, 2011Co-Authors: D. Zhu, Michael J. Tudor, N. R. Harris, Steve Beeby, Computer ScienceAbstract:This paper presents a low-profile, planar electromagnetic vibration energy harvester integrated with a Halbach array. Halbach array is a special arrangement of permanent magnets that doubles the magnetic field on one side of the array while cancelling the field to near zero on the other side. Using this arrangement can improve electromagnetic coupling in a limited space. The energy harvester has a resonant frequency of 44.9Hz and generated an average power of over 120µW when excited at 0.3g (1g = 9.8m•s-2). The electromagnetic vibration energy harvester reported here is only 4mm thick, which makes it one of the thinnest electromagnetic energy Harvesters among existing non-MEMS devices.
Xu Wang - One of the best experts on this subject based on the ideXlab platform.
-
Similarity and duality of electromagnetic and piezoelectric vibration energy Harvesters
Mechanical Systems and Signal Processing, 2015Co-Authors: Xu Wang, S. Watkins, Xingyu Liang, Sabu John, Han Xiao, Xinghuo Yu, Haiqiao WeiAbstract:A frequency analysis has been conducted to study vibration energy harvesting performance and characteristics of a single degree of freedom vibration energy harvester connected to a single load resistor based on the Laplace transfer method and physical models of a voltage source. The performance and characteristics of electromagnetic and piezoelectric Harvesters have been analysed and compared. The main research outcome is the disclosure of similarity and duality of electromagnetic and piezoelectric Harvesters for both the energy harvesting efficiency and the normalised resonant harvested power using only two dimensionless characteristic parameters: the normalised resistance and the normalised force factor. The dimensionless resonant harvested power and energy harvesting efficiency analysis allows for a parameter study and optimization of the ambient vibration energy Harvesters from macro-to nano-scales and for evaluation of the vibration energy harvester performance regardless of the size and type.
-
A study of electromagnetic vibration energy Harvesters with different interface circuits
Mechanical Systems and Signal Processing, 2015Co-Authors: Xu Wang, Xingyu Liang, Haiqiao WeiAbstract:A dimensionless analysis of piezoelectric vibration energy harvester was conducted in the previous work where the harvested power and energy harvesting efficiency were normalised and determined from two non-dimensional variables of resistance and force factor. This paper has developed a dimensionless analysis of an electromagnetic vibration energy harvester where the harvested power and energy harvesting efficiency are normalised and determined from two similar non-dimensional variables of resistance and equivalent force factor. The harvested power and efficiency are compared for the electromagnetic harvester with different interface circuits. The aim is to disclose some similarity and limitations of the piezoelectric and electromagnetic Harvesters in a dimensionless scale.
-
A Review of Piezoelectric Vibration Energy Harvesting Techniques
International Review of Mechanical Engineering-IREME, 2014Co-Authors: Han Xiao, Xu WangAbstract:In this paper, recent published techniques for vibration energy harvesting with piezoelectric materials have been summarized. The various techniques described are classified in terms of linear and nonlinear vibration energy Harvesters, harvesting electrical circuits, large scale vibration energy harvesting concept. The focus is on linear vibration energy harvester but with multiple resonant mode models. The paper concluded with an overview of vibration energy harvesting techniques that aim to maximize the extracted power and the future utilization of the vibration energy harvester.
Nick Harris - One of the best experts on this subject based on the ideXlab platform.
-
Vibration energy harvesting using the Halbach array
Smart Materials and Structures, 2012Co-Authors: D. Zhu, Steve Beeby, John Tudor, Nick HarrisAbstract:This paper studies the feasibility of vibration energy harvesting\nusing a Halbach array. A Halbach array is a specific arrangement\nof permanent magnets that concentrates the magnetic field on one\nside of the array while cancelling the field to almost zero on the\nother side. This arrangement can improve electromagnetic coupling\nin a limited space. The Halbach array offers an advantage over conventional\nlayouts of magnets in terms of its concentrated magnetic field and\nlow-profile structure, which helps improve the output power of electromagnetic\nenergy Harvesters while minimizing their size. Another benefit of\nthe Halbach array is that due to the existence of an almost-zero\nmagnetic field zone, electronic components can be placed close to\nthe energy harvester without any chance of interference, which can\npotentially reduce the overall size of a self-powered device. The\nfirst reported example of a low-profile, planar electromagnetic vibration\nenergy harvester utilizing a Halbach array was built and tested.\nResults were compared to ones for energy Harvesters with conventional\nmagnet layouts. By comparison, it is concluded that although energy\nHarvesters with a Halbach array can have higher magnetic field density,\na higher output power requires careful design in order to achieve\nthe maximum magnetic flux gradient.
