International Journal of Applied Electromagnetics and Mechanics - Volume 46, issue 4

Authors: Zhang, Jian-Ping | Fang, Fang | Pan, Wei-Guo | Wu, Helen | Ren, Jian-Xing

Article Type: Research Article

Abstract: In order to study PM2.5 removal performance under multi-field coupling and applied magnetic field, a mathematical model was proposed to analyze the interaction between fluid flow field, electro- magnetic field and particle dynamic field. The computational fluid dynamics method and FLUENT were employed to numerically simulate the PM2.5 removal performance in a Wire-pipe ESP. The effects of magnetic field on PM2.5 collection efficiency at different working voltages and gas velocities were discussed. The results indicate that …the influence of applied magnetic field on PM2.5 collection in the wire-pipe ESP becomes more obvious with the increase of the particle diameter, and the increment of PM2.5 grade efficiency decreases with the increasing magnetic flux density in a certain range of particle diameters. Furthermore, the effect of magnetic field on PM2.5 collection increases with a decrease of working voltage or an increase of gas velocity, and PM2.5 collection efficiency declines at the same time. At a lower flue gas velocity, the impact of flue gas velocity on PM2.5 overall efficiency is more significant than that of applied magnetic field. Show more

Keywords: Wire-pipe ESP, PM2.5, collection efficiency, applied magnetic field, multi-field coupling

DOI: 10.3233/JAE-141970

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 739-750, 2014

Authors: Pang, Yan | Xia, Hao

Article Type: Research Article

Abstract: A Free Piston Energy Converter (FPEC) is a combination of a linear combustion engine and a linear electrical machine. It is a potential technology for series hybrid vehicles, as well as stationary power generation applications. In a free piston energy converter, the piston is not connected to a crank-shaft. Instead, the piston movement is "free" and controlled by a linear hydraulic or electric machine. The major advantages of such a design over the conventional ones are …the simpler engine layout and much improved conversion efficiency. Unlike other traditional modeling method, in this paper, the free piston converter is modeled as a hybrid automaton. A hierarchical hybrid controller is designed based on this model. The hybrid controller includes a discrete controller which is in charge of switching actions and a continuous controller which compute the electro-magnetic force. High-fidelity simulation results are provided to illustrate the applicability and performance of developed control law. Show more

Keywords: Hybrid systems, control, electro-magnetic force, free piston energy converter

DOI: 10.3233/JAE-141971

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 751-762, 2014

Authors: Tang, Mingsheng | Zou, Huiming | Xu, Hongbo | Shao, Shuangquan | Tian, Changqing

Article Type: Research Article

Abstract: The stroke and natural frequency are key controlling quantities for linear compressor controller. This paper proposes a phasor algorithm for the linear compress stroke and natural frequency calculation. The phasor algorithm employs vectors to express the voltage, current and velocity respectively for the calculation in frequency domain. A test bench has been installed, and the feasibility of phasor algorithm is verified with the linear compressor load changing. The relative deviation of the calculated stroke can be …achieved within ± 3% experimental results at 0.4 MPa, 0.5 MPa and 0.6 MPa discharge pressure respectively. The calculated results shows that the computation time of phasor algorithm is one-third shorter than that of time domain algorithm, which means it is possible to employ relatively low energy consumption and low cost hard ware. The calculation natural frequency decreases with the stroke increases at 0.4 MPa, 0.5 MPa and 0.6 MPa discharge pressure respectively, and the tested motor efficiency reaches a maximum when the calculated natural frequency equals to the operating frequency. Show more

Keywords: Linear compressor control, stroke estimation, natural frequency estimation, phasor algorithm

DOI: 10.3233/JAE-141972

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 763-774, 2014

Authors: Cheng, Qiang | Zhang, Zhen-Dong | Guo, Hui | Xie, Nai-Liu

Article Type: Research Article

Abstract: The GDI (Gasoline Direct Injection) injector is influenced by electro-magnetic-thermal coupling, and has strong nonlinearity and coupling. Temperature rise greatly impacts the performance of the GDI injector and makes the ECU of the engine difficult to control fuel injection quantity accurately. According to the coupling relationship of electric, magnetic and thermal subsystems of the GDI injector, the physical model of coupled process was established. The energy loss and transformation of the GDI injector in work …process was explored, and revealed that the energy loss in electromagnetic conversion was a key factor to cause the GDI injector temperature rise. The energy loss coming from electromagnetic conversion was regarded as heat source. The temperature field of the GDI injector contains heat conduction and thermal radiation was analyzed based on the finite element theories. By using the ANSYS software to simulate multiple physical fields of the GDI injector, and then experiment method to verify the simulation results, distribution characteristics of temperature field and variations of temperature rise effect on the performance of the GDI injector was analyzed. The results show that, higher temperature rise is concentrated on coil and core part and with the higher temperature rise the response time of the GDI injector get longer, the fuel injection quantity becomes less. The value and pulse width of the holding current I have great impact on the GDI injector performance and temperature rise. Show more

Keywords: GDI injector, temperature rise, electric-magnetic-thermal coupling, finite element simulation, dynamic response

DOI: 10.3233/JAE-141973

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 775-792, 2014

Authors: Kaikaa, M.Y.

Article Type: Research Article

Abstract: In this paper, a precise approach is proposed to detect DE in induction motors under unbalanced voltages. To achieve this goal, one essential problem is dealt with: The frequencies of the components caused by the DE in the stator current spectrum are similar to some of the frequencies introduced by the unbalanced voltages. Thus, the present paper attempts to explain, analytically, experimentally and by simulation, the generation process of all frequency components that are a function …of the unbalanced voltages and the DE. For that reason, a detailed analytical study for three-phase induction motor working with DE is performed. First, an analytical expression for the mutual inductances between stator phases and rotor loops under DE is derived using mixture of winding function and Fourier series approach. Then, both theoretical and simulation studies are presented in order to show how the stator current is influenced by the simultaneous presence of DE eccentricity and unbalance supply voltages. Finally, experimental results have been presented to validate the analytical and simulation results. Show more

Keywords: Dynamic eccentricity, unbalanced voltages, induction motor, fault diagnosis, rotor slot harmonics

DOI: 10.3233/JAE-141974

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 793-808, 2014

Authors: Afrand, Masoud | Farahat, Said | Nezhad, Alireza Hossein | Ali Sheikhzadeh, Ghanbar | Sarhaddi, Faramarz

Article Type: Research Article

Abstract: In the present paper, numerical analysis of an electrically conducting fluid under the influence of a magnetic field in an inclined cylindrical annulus is presented. The inner and outer walls are kept at constant temperatures, and the top and bottom walls are assumed to be adiabatic. The numerical method used to solve the nonlinear governing equations of the problem is finite volume scheme. The computational results reveal that the effect of transverse magnetic field is more …significant than that of the axial magnetic field on the average Nusselt number. Also, it is found that when the magnetic field is perpendicular to the axis of annulus, the average Nusselt number decreases from 7.8 to 4.7 with an increase in Ha from 0 to 60. Show more

Keywords: Tilted cylindrical annulus, natural convection control, various magnetic fields, electrical potential, 3D numerical simulation

DOI: 10.3233/JAE-141975

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 809-821, 2014

Authors: Lv, Chunfeng | Liu, Weiwen | Jiang, Yingying | Zhao, Hui

Article Type: Research Article

Abstract: Analytical method for eddy current evaluation is an attractive field of learning the concept of electromagnetic phenomena. This paper proposes an analytical approach to a transverse eddy current displacement sensor with a rectangular testing coil. Solving domain in the Cartesian coordinate system is limited to finite extents through imposing artificial boundaries at x and y axis, and solutions to the electromagnetic field are expressed as double series. Complete closed-form expressions based on second order vector potential …for the electromagnetic field in each region can be obtained from the continuity conditions at the interfaces by mode matching. Closed-form expressions of the eddy current density as well as coil impedance related to the transverse displacement can thus be derived, and the calculated results show good agreement with the experimental results. Show more

Keywords: Analytical modelling, eddy current, transverse displacement, rectangular coil

DOI: 10.3233/JAE-130060

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 823-834, 2014

Authors: Zhang, Chao | Ji, Hongli | Qiu, Jinhao | Wu, Yucheng | Hu, Ning

Article Type: Research Article

Abstract: This study presents a novel imaging method in passive sensing structural health monitoring (SHM), for locating impact damage in real-time on a plate-like structure. So far, many imaging methods have already been applied in active sensing SHM to locate the damages. However, seldom of the imaging methods can be directly used to locate the impact in passive sensing SHM. In order to avoid solving the hyperstatic hyperbolic equations and generate an informative image for locating the …impact damage, the proposed method combines the imaging method with probability calculation. Moreover, to demonstrate the feasibility of the proposed method, the experimental results are presented and analyzed. From the results, the proposed method shows an interesting phenomenon that the accuracy of the impact localization depends on the impact position. Finally, a detailed analysis of the method accuracy is discussed. Show more

Keywords: Structural health monitoring, impact localization, imaging method

DOI: 10.3233/JAE-140092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 835-844, 2014

Authors: Su, Y.H. | Liu, Y.P. | Vasic, D. | Costa, F. | Wu, W.J. | Lee, C.K.

Article Type: Research Article

Abstract: In this paper, we propose a new design of a piezoelectric transformer (PT) for low-profile DC/DC converter applications, which increases the output power by using heat transfer equipment. We examined several parameters, which allow us to produce a piezoelectric transformer with optimal efficiency. Instead of looking at the typically optimal loading condition of the PT, we consider the influence of the temperature rise on losses. When the vibration velocity is too large, the piezoelectric transformer generates …heat unstably until it cracks. By maintaining the vibration mode and limiting the heat produced by the PT, this design can enhance the power capacities of the PT and thus increase the output power of the DC/DC converter. A finite element analysis (FEA) approach with COMSOL Multiphysics was made to predict PT's working temperature. A theoretical-phenomenological model was also developed to explain the relationship between the equivalent losses resistances and the input voltage at different temperatures. It will be shown that the vibration velocity as well as the heat generation increases the losses. A large vibration velocity and generated heat may cause the temperature feedback loop to enter into an unstable state. We began by modeling a piezoelectric transformer in a DC/DC converter configuration in order to determine the design constraints and variables such as the maximum mechanical current, the temperature distribution, the PT geometrical configuration and the energy balance. In our design, the PT power capacity increases 3 times (i.e. from 4.54 W to 13.29 W) at specific temperature and the effects of the different cooling methods of the system were verified. The study comprises of a theoretical part and experimental proof-of-concept demonstration of the proposed design method. Show more

Keywords: Piezoelectric transformer, power capacity, power density

DOI: 10.3233/JAE-140093

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 845-857, 2014

Authors: Lin, Xiujuan | Chen, Haiyan | Jiang, Chao | Zhou, Kechao | Zhang, Dou

Article Type: Research Article

Abstract: Finite element analysis was performed on the representative volume element of piezoelectric elements with interdigitated electrodes (IDEs). The variations of piezoelectric material properties during poling were considered in the analysis. The numerical results of models with different piezoelectric polarization states were compared with the result given by the so called uniform field model. Though different optimum electrode finger widths were obtained for different models, narrower electrode finger could enhance the actuation performance. …The models indicated the stress concentrated at the edges of the finger electrode. Wider electrode finger would be beneficial for reducing the risk of material failure. The model with two different polarization states could be used to predict the strain and stress of MFCs with wider electrode finger to minimize the computational complexity. The modeling approach developed in this study allowed for a better understanding on the overall effects in piezoelectric materials with IDE structures. Show more

Keywords: Finite element analysis, electrode finger width, polarization state, strain, stress

DOI: 10.3233/JAE-140094

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 859-866, 2014

Authors: Yue, H.H. | Jiang, Jing | Long, Y.F. | Song, Y.J.

Article Type: Research Article

Abstract: In order to improve the technical specifications of space reflectors, antennas and other payloads on Earth observation, space communication, deep space exploration and other fields of space applications, people urgently need to enhance the surface shape control accuracy of these large complex curvature flexible structures. Based on the photovoltaic effect and converse piezoelectric effect, this paper presents a non-contact shape-adjusting method which adopts a new space energy conversion: using the PLZT photovoltage, …which is controlled by the ultraviolet, to activate the PVDF attached on the flexible structure surface, and adjust and control the structure's shape. This paper firstly built up the electric model of the PLZT/PVDF hybrid drive, derived the constitutive relation of light-electric-mechanical energy field conversion, and determined the key parameters in mathematical model by principle experiments. Then, taking a flexible cantilever beam as the control object, actuation equation of the PVDF bonded structure was built, and actuation properties and influence factors of the cantilever beam actuated by the PLZT/PVDF hybrid drive were simulated and analyzed. After that, the hybrid drive experiment system was built up, and deflecting effect of using ultraviolet illuminated PLZT to actuate PVDF bonded cantilever beam was tested, whose result verified the validity of theoretical modeling and simulation analysis. Lastly, characteristics of the hybrid drive method and conventional PVDF driving were compared, and space application direction of this method was pointed out. Show more

Keywords: Shape adjustment, PLZT, PVDF, hybrid drive

DOI: 10.3233/JAE-140095

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 867-877, 2014

Authors: Ji, Hongli | Qiu, Jinhao | Nie, Hong | Cheng, Li

Article Type: Research Article

Abstract: With the rapid development of the aerospace industry, the control of aircraft structural vibration becomes increasingly important. Semi-active vibration control method based on synchronized switch damping have been attracted more attention due to its robustness compared with passive approaches and simplicity compared with active approaches. In this paper, three SSD semi-active control methods combined with a modal observer were applied to multimodal vibration suppression of an aircraft panel with stiffeners, and their …effectiveness was verified by experimental results. A state observer was built based on the experimentally identified state-space model of the panel. Modal displacement of the panel was identified on line using the state observer and used in switch control of different piezoelectric actuators. Since the vibration characteristics of the panel with stiffeners was very complicated and its natural frequencies were distributed densely, use of the identified modal displacement as the reference signal for voltage switching in SSDI, SSDV and SSDNC improved the control effect for some specific modes and simplified the system. Good performances of vibration suppression were achieved in both single-mode control and multimodal control. Show more

Keywords: Piezoelectric elements, synchronized switch damping, semi-active control, aircraft panel, state observer

DOI: 10.3233/JAE-140096

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 879-893, 2014

Authors: Chen, Song-Mao | Zhou, Jin-Juan | Hu, Jun-Hui

Article Type: Research Article

Abstract: Linear uniform beams have been extensively investigated as a typical piezoelectric vibration energy harvesting mechanism in both conventional cantilever-beam-based harvester and a novel internal impact type energy harvester, the latter is of broad bandwidth and frequency up-converting capability and therefore quite suitable to low frequency ambient vibrations. To sufficiently utilize the space of the existing internal impact type energy harvester, a bent metal beam with distributed piezoelectric patches is proposed and investigated …as the vibration energy harvesting module. A prototype harvester has been built and performances including the voltage and output power have been tested by experiments and analyzed by the finite element analysis. Both experiment and finite element analysis show that the proposed structure can effectively harvest vibration energy. And the optimal position for energy harvesting in this structure is also found. This work indicates that the frame of the existing internal impact type energy harvester may be used to harvest vibration energy, if it is bonded with distributed piezoelectric patches, which gives a way to increase its power density. Show more

Keywords: Piezoelectric energy harvesting, impact, bent beam, finite element analysis

DOI: 10.3233/JAE-140097

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 895-904, 2014

Authors: Wang, Shuyun | Liu, Dianlong | Kan, Junwu | Zhang, Zhonghua | Yu, Li | Xu, Hailong

Article Type: Research Article

Abstract: To improve energy generating capability and reliability/strength, a novel piezohydraulic generator for low frequency vibration was presented. The piezohydraulic generator consisted mainly of a double-rod hydraulic cylinder for conversion of vibration energy to fluid energy and piezodiscs for conversion of the fluidic energy to electric energy. A vibration function and energy-conversion model of the generator was established based on theory of vibration analysis and simulated to obtain the influence of backpressure on …energy generation as well as optimal frequency. The analysis results show that both the energy generation and optimal frequency increases with the rising of backpressure under given other parameters. A piezohydraulic harvester was fabricated and tested at different backpressure. Both the optimal frequency and the relative peak voltage/power increase with the rising of backpressure. At 0.2 MPa and 0.8 MPa, the peak-voltage and the relative optimal-frequency are 9 V/11 Hz and 112 V/17.5 Hz respectively. Similarly, the peak-power and the relative optimal-frequency are 0.58 mW/13 Hz and 11.63 mW/17 Hz respectively. The research results indicate that a piezohydraulic generator can be used to harvest energy from a low-frequency and high-level vibration source. Show more

Keywords: Piezoelectric, piezohydraulic, energy harvesting, solid-fluid coupling vibration

DOI: 10.3233/JAE-140098

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 905-916, 2014

Authors: Jiang, Jing | Wang, Lei | Yue, Honghao | Deng, Zongquan | Tzou, Hornsen

Article Type: Research Article

Abstract: Photovoltaic materials, which can directly turn light energy into electric energy, can offer the advantage of generating large voltages without external power supplies. When a near ultraviolet light illuminates on polarized PbLaZrTi (PLZT) materials, an electrical field can be generated along the spontaneous polarization direction due to the phovoltaic effect. This voltage generation mechanism exhibits many advantages, such as (1) high electrical output voltage, (2) wireless energy generation, (3) immune from electric/magnetic …disturbances, (4) remote or non-contact control. In this study, Distributed vibration control of cylindrical shells using a hybrid photovoltaic/piezoelectric actuation mechanism is investigated. The light-driven photovoltaic generator induced voltage is used to drive a skew-quad piezoelectric actuator which can induce non-uniform control froces and control moments. Based on theoretical analysis and experimental validation, the constitutive equations defining the piezoelectric actuator induced actuation strain under the actuation mechanism are presented. Each region of the actuator system can induce both positive and negative control forces and moments using logical switches to shift the sign of control voltage of actuator system. Control effectiveness with constant light intensity control algorithm is evaluated and the time history analysis is presented. Show more

Keywords: Hybrid photovoltaic/piezoelectric actuation, cylindrical shell, non-uniform control forces

DOI: 10.3233/JAE-140099

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 917-926, 2014

Authors: Qiu, Lei | Yuan, Shenfang | Yang, Weibo

Article Type: Research Article

Abstract: Structural health monitoring (SHM) technology is a reliable, efficient and economical approach to increase the safety and reduce the maintenance cost of high performance structures. Among the existing SHM methods, piezoelectric transducers (PZTs) array and Lamb wave based SHM methods are sensitive to small damage and studied by many researchers. In this paper, aiming at developing a practical method for on-line localization of damage and impact on aircraft composite structure which can take advantage of time …reversal focusing and does not rely on the transfer function, a phase synthesis based time reversal focusing method is proposed and a twin-PZTs array arrangement based damage imaging method is discussed first. In this method, damage and impact images are given out directly through time reversal focusing and the other imaging processes such as the delay-and-sum imaging method adopted in many researches of time reversal focusing are not needed. And then, a kind of PZTs smart layer (PSL) with electromagnetic shielding is developed. For real application of SHM, an integrated multi-channel scanning system (ISS) with impact and damage monitoring function is developed thirdly. The ISS can scan large numbers of actuator-sensor channels and estimate impact and damage automatically. Finally, A SHM demonstration system is built on a carbon fiber composite panel with many bolt holes and stiffeners of an aircraft wing box based on the damage and impact imaging method, the PSL and the ISS. The demonstrating results show good performance of the whole SHM system. Show more

Keywords: Structural health monitoring, piezoelectric transducer, time reversal, damage imaging, impact imaging

DOI: 10.3233/JAE-140100

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 927-941, 2014

Authors: Sudo, Seiichi | Shinozaki, Michihiro | Nishiyama, Hideya

Article Type: Research Article

Abstract: This paper is concerned with a novel optical diaphragm using magnetic fluid and a permanent magnet. The optical diaphragm consisting of a kerosene-based magnetic fluid and a small ring-shaped Nd_{2} Fe_{14} B permanent magnet was designed. The magnetic fluid diaphragm was driven by the external magnetic field. The experimental apparatus consists of the test magnetic fluid diaphragm system and the optical measurement system. Frequency characteristics of the magnetic fluid diaphragm …in the alternating magnetic field were studied experimentally. The alternating magnetic field was generated by applying alternating current voltage to a Helmholtz coil. The alternating current signal was supplied from the frequency synthesizer. The dynamic responses of magnetic fluid diaphragm were analyzed with a high-speed video camera system. It was revealed that the amplitude of magnetic fluid hole oscillation depended on the frequency of magnetic field. The effect of the applied voltage on the amplitude of hole oscillation was also revealed. Show more

Keywords: Magnetic fluids, optical diaphragm, interfacial phenomena, alternating magnetic field

DOI: 10.3233/JAE-140101

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 943-949, 2014

Authors: He, Rongbo | Zheng, Shijie

Article Type: Research Article

Abstract: In this paper, the multi-modal vibration control of a simply supported thin cylindrical shell laminated with photostrictive actuators is studied. First, the photo-electric/shell coupling equations of a cylindrical shell laminated with the multi-layer actuator configuration are presented. Moreover, in view of the nonlinear and time-variant characteristics of photostrictive actuators, a fuzzy neural network (FNN) controller with adaptive learning rates is developed to attenuate multi-mode vibration of photo-electric laminated thin cylindrical shells. This …approach has learning ability for responding to the time-varying characteristic of the multi-mode vibration induced by disturbance. Its control rule bank can be established and modified continuously by on-line learning. Finally, numerical simulation results are provided to show that the proposed intelligent controller could effectively suppress multi-mode vibration of photo-electric laminated thin cylindrical shells. Show more

Keywords: Photostrictive actuators, multi-layer actuator configuration, thin cylindrical shell, fuzzy neural network, multi-modal vibration

DOI: 10.3233/JAE-140102

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 951-963, 2014

Authors: Wang, X.J. | Huang, J.H. | Wang, J. | Yue, H.H.

Article Type: Research Article

Abstract: Lead lanthanum zirconate titanate (PLZT) ceramics can transform the light energy into the mechanical energy without electromagnetic noise. The optical and direct driven based on PLZT's photostrictive effect, which is also green driven and non-contact driven, has many advantages in micro-driven and structure vibration control. However the existing constitutive equations of PLZT ceramics do not consider the influence from both light intensity and PLZT ceramic sizes (i.e. length, width and thickness) to photostrictive effect. In …this paper, the effect of the light intensity, aspect ratio and the thickness of the PLZT ceramic on the photostrictive strain is researched based on the equivalent electrical model of the PLZT. A new photostrictive mathematical model of PLZT with LED-UV illumination is established. The mathematical model is validated through the photostrictive static experiments of PLZT samples with various sizes and light intensities. Show more

Keywords: PLZT, photostrictive effect, constitutive equations

DOI: 10.3233/JAE-140103

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 965-977, 2014

Authors: Jiang, Xuezheng | Gu, Xiaoyu | Wang, Jiong

Article Type: Research Article

Abstract: This paper presents a novel piezoelectric harvester to convert ambient vibrations into usable electrical energy. Unlike the normal cantilever beam structure, the piezoelectric harvester developed in this paper is based on the wafer-stack configuration, which is appropriated for large force vibrations. Firstly, two electromechanical models (without and with a rectifier circuit), considering both the mechanical and electrical factors of the harvester, were built to characterize the harvested electrical power across the external …load. Exact closed-form expressions of the electromechanical models have been given to analyze the maximum harvested power and the optimal resistance. It was shown that the harvested electrical power depends on the external vibration characteristics, the natural frequency, the mechanical damping factor, the normalized electrical load, the stiffness of the harvester and the overall electromechanical coupling coefficient of the harvester. Finally, a shake table experimental testing was conducted to evaluate the feasibility of the proposed piezoelectric wafer-stack harvester under standard sinusoidal loadings. Experimental results show that the harvester can generate a maximum 16 mW DC electrical power for sinusoidal loading with 3040 N amplitude and 2 Hz frequency, and the harvested electrical power is proportional to the strength of the exciting vibration. Show more

Keywords: Energy harvesting, piezoelectric, wafer-stack, electromechanical model

DOI: 10.3233/JAE-140104

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 979-990, 2014

Authors: Li, Hongmei | Chen, Hong-En | Yuan, Zhensheng | Cai, Wenlu | Li, Yong | Chen, Zhenmao | Uchimoto, Tetsuya | Takagi, Toshiyuki | Yoshihara, Kensuke

Article Type: Research Article

Abstract: To explore the mechanism of damage-induced magnetization for paramagnetic austenitic stainless steel, the differences of damage-induced magnetizations between an austenitic stainless steel and a carbon steel are experimentally studied. Various plastic strains are introduced into the test-pieces of the austenitic stainless steel of 304 type and S185 carbon steel material. The residual plastic strains and the damage-induced magnetic fields nearby the test-pieces, the volume fraction of the damage-induced ferromagnetic martensitic phase in …austenitic stainless steel test-pieces are measured. The relationships between the residual plastic strain and the damage-induced magnetic field of two materials are investigated and their differences are compared. In addition, by establishing the relationships of the damage-induced magnetic field with the damage-induced martensitic phase, the effect of the phase transformation on the damage-induced magnetization of austenitic stainless steel is analyzed. Show more

Keywords: Plastic deformation, damage-induced magnetization, austenitic stainless steel, carbon steel

DOI: 10.3233/JAE-140105

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 991-996, 2014

Authors: Mlyniec, Andrzej | Ambrozinski, Lukasz | Packo, Pawel | Bednarz, Jaroslaw | Staszewski, Wieslaw J. | Uhl, Tadeusz

Article Type: Research Article

Abstract: The performance of many mechanical structures highly depends on weather conditions in region of operation. One of the main limiting factors of their performance in cold regions is the icing process. Icing of structures can be a reason of mechanical and electrical failures and can be dangerous for people working closely to, for instance, rotating wind turbine blades. To prevent de-icing process an inspection system informing about the possibility of collecting ice on surface of operating …structures is of particular interest. The following work considers a numerical modeling approach and experimental investigations of the ice detection and de-icing process. The proposed numerical model is based on the cohesive-zone approach used to simulate the delamination at the ice/aluminum interface. Model parameters are specified in terms of fracture energy as a function normal and shear deformation at the interface. A linear elastic traction separation law prior to damage and progressive degradation of the material stiffness after failure is assumed. The ice detection and removal is accomplished by ultrasonic waves excited by the piezoelectric transducers. The experimental results for aluminum plate with ice layers are presented. The results confirmed possibility of icing identification by means of piezoelectric transducers, although ice removal effectiveness depends on the thickness of ice layers. Finally, a proposal of a new deicing adaptive system is given. Show more

Keywords: Wave propagation, deicing, adaptive system

DOI: 10.3233/JAE-140091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 997-1008, 2014

Authors: Hu, Kun | He, Fengyou

Article Type: Research Article

Abstract: Traditional synchronous motor system has complicated structure and is difficult to maintain. In view of the mentioned problem, this paper aims to propose a new structure brushless synchronous motor where AC exciter and synchronous motor using the same core. Two concentric single-phase winding grooves are cut on stator and rotor respectively, with the stator single-phase field winding laying in the stator single-phase winding groove, and the rotor AC induction winding laying in the rotor single-phase winding …groove. The AC power from AC exciter is rectified by the rotating rectifier for the DC field winding. The results of the proposed structural design and FEA of the new structure brushless wound field synchronous motor show that the new structure is simple in structure, low in loss, high in efficiency and promising in its future application. Show more

Keywords: Wound field synchronous motor, AC exciter, rotating rectifier, brushless excitation, finite element analysis

DOI: 10.3233/JAE-140071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 1009-1019, 2014

Article Type: Other

Abstract: Author Index Volume 46 (2014)

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 4, pp. 1021-1030, 2014