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

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