Journal of Advanced Science
Online ISSN : 1881-3917
Print ISSN : 0915-5651
ISSN-L : 0915-5651
18 巻 , 1+2 号
Intelligent Materials and Structures 2005
選択された号の論文の40件中1~40を表示しています
International Joint Conference of 6th JFSIMS & 2nd SMEBA 2005
Paper
Paper
  • Toshiyuki NAKATA, Hiroshi ASANUMA, Toshiaki TANAKA, Masashi KOMORl ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 6-9
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    This paper describes fabrication, evaluation and demonstration of the active laminate proposed by Asanuma. It was made by hot-pressing of an aluminum plate as a high CTE material, a unidirectional CFRP prepreg as a low CTE material and an electric resistance heater, a KFRP prepreg as a low CTE material and an insulator between them, and copper foils as electrodes. In this study, its performances such as shape change as a function of electric-resistance heating temperature were examined and compared with those of a stainless steel type one. As the results, it became clear that 1) the curvature of the active laminate linearly changes only in the fiber direction as a function of temperature between room temperature and its hot pressing temperature by electric resistance heating of carbon fiber in the CFRP layer, and 2) the active laminate was made into complicated forms, that is, a hatch and a stack types, and their actuation performances were successfully demonstrated.
Letter
  • Kotoji ANDO, Koji TAKAHASHI, Kotokaze FURUSAWA, Wataru NAKAO
    原稿種別: Letter
    2006 年 18 巻 1+2 号 p. 10-15
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Recently, the authors developed Si3N4, Al2O3 and mullite ceramics with good self-crack-healing abilities. It was shown that the optimized crack-healing condition to get high temperature strength was: 1573K, 1 h, in air, and the healed zone exhibited the same strength as the base material. Using this good healing ability, a new methodology to guarantee the reliability of ceramic components "crack-healing + proof test" was proposed. However, if a crack initiated during service, reliability would be severely impaired. Therefore, if a material can crack-heal during service, and if the healed zone has enough strength at the temperature of healing, it would be very desirable for structural integrity. From the above points of view, a new methodology to guarantee the structural integrity of ceramic components using in-situ crack-healing ability was proposed and the usefulness was discussed using the test results in terms of crack-healing behavior and proof test theory by the authors.
Paper
  • Hiroshi ASANUMA, Kiyotada KATO, Takeshi MOCHIZAKl, Genji HAKODA, H ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 16-19
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    The present paper describes development of active fiber-reinforced metals utilizing their thermal deformation caused by non-uniform distribution or combination of continuous and discontinuous fibers. These types of SiC/Al composites, that is, a laminate of continuous-fiber layer and unreinforced one, that of discontinuous-flber layer and unreinforced one, and that of continuous-fiber layer and discontinuous-flber one were fabricated, and their thermal deformation characteristics were investigated. As the results, all of the composites curve unidirectionally in the flber direction by cooling from the hot pressing temperature. Though the curvature of the composite reinforced on one side decreases by reducing the fiber length, the curvature change during thermal cycles between room temperature and 813 K can be clearly observed even in the case of the discontinuous flber type. The tensile strength of the composite reinforced with continuous flber on one side successfully increases by lamination of the continuous-fiber layer and the discontinuous one. The curvature of this type of active composite can also reproducibly change during the thermal cycles due to the difference of the fiber lengths, and exists between the continuous-flber type and the discontinuous-fiber type ones.
Letter
Paper
  • Kosuke NAGAYA, Ying Ll, Kodo KUBO , Yoshinori ANDO, Yutaka SAKAMOTO ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 23-26
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Recently, low noise gears without lubrication are required for business machines and robots, because they are used in open space. The present article provides a new type gear consisting of steel and resin (called Delrin-100), which has good lubrication characteristics. Our gear has profile shifted steel gear teeth. Delrin-100 resin is inserted in a grove, which is cut around the gear teeth of the steel gear so as to have strong gear teeth. Hence, the tooth made of Delrin resin is supported at both sides. This means that only resin gear tooth contacts to the follower gear tooth, but steel gear tooth does not contact. Production processes are presented for the gear, and its characteristics are investigated. It is ascertained that the strength of our gear is greater than that of a plastic gear, and noise of our gear is small in comparison with plastic gears. The design method is presented, and effects of frictions on the position control are also investigated.
Bio
Review
Paper
  • R. MAALOUF , Nicole JAFFREZIC-RENAULT, O. VITTORI , M. SIGAUD, Y. S ...
    原稿種別: Review
    2006 年 18 巻 1+2 号 p. 31-36
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Diamond-Like Carbon and Carbon-Like Nanocomposite electrodes, novel materials in the field of biosensors, made with different ratio of sp3/sp2 carbon hybridization or doped with elements such as Ni, Si and W, were characterized electrochemically by cyclic voltammetry and by amperometric measurements towards hydrogen peroxide. SiCAr1 and SiCNi5% were chosen as sensitive transducers for elaboration of amperometric glucose biosensors. Immobilization of glucose oxidase was carried out by cross-linking with glutareldehyde. Measurements were made at a fixed potential + 1.0 V in 40 mM phosphate buffer pH 7.4. SiCAr1 seems to be more sensitive for glucose (0.6875 μA/mM) then SiCNi5% (0.3654 μA/mM). Detections limits were respectively 20 μM and 30 μM. Michaelis-Menten constants for the two electrodes were found around 3 mM. 48% and 79% of the original response for 0.5 mM glucose remained respectively for both electrodes after 10 days.
Letter
  • Kohji MITSUBAYASHI, Kimio OTSUKA, Teruyoshi GOTO, Tomohiro SHINODA, ...
    原稿種別: Letter
    2006 年 18 巻 1+2 号 p. 37-38
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    A novel colorless and odorless chemical code system was constructed with gas-phase biosensors (bio-sniffers). Three volatile chemicals, hydrogen peroxide (H2O2), lactate and choline vapors were used for chemical code. The bio-sniffer devices for these 3 chemicals were constructed by applying catalase, lactate oxidase and choline oxidase immobilized membrane to a Clark-type oxygen electrode, respectively. Each bio-sniffer showed high selectivity for their chemical vapor due to the substrate specificity of the enzyme without crosstalk error. Thus, a 3-bit (8-channel) chemical code was successfully recognized and distinguished by 3 kinds of the bio-sniffers.
Letter
  • Tetsuya HARUYAMA, Hiroaki SAKAMOTO, Shinya lKENO
    原稿種別: Letter
    2006 年 18 巻 1+2 号 p. 39-40
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    The technology of mercaptide self assembly has previously been used to immobilize molecules onto epitaxial metals but is not practical for many surfaces. In this study, a designed tag was employed for the electrochemical immobilization of protein on metals (ECtag). In the case of protein, ECtag can be designed with a 6-mer amino acid (alfa-amino-1H-imidazole-4-propionic acid) homopeptide. It was employed as an ECtag ligand and was introduced to a objective protein molecule through genetical process. ECtag forms co-ordinate bonds with Ni2+ and other divalent metal ions. Protein A (specific affinity protein against igG) was chosen as a model protein for the immobilization, and was genetically tagged with an ECtag for immobilization onto a Pt electrode surface through the reduction of ECtag:Ni2+ to ECtag:Ni by the electrode potential. The immobilization process can be performed through very simple wet-electrochemical process.
Letter
Letter
Paper
  • Seiichi SUDO, Tetsuya YANO, Yasuhiko KAN , Yuzuru YAMADA, Koji TS ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 46-49
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    This paper is concerned with the swimming characteristics and the structure dynamics of diving beetle legs. Diving beetles are highly adapted for aquatic life. When swimming, all of these insects use their flattened, paddle-shaped hind legs like oars. Their hind legs have a thick fringe of swimming hairs. Since diving beetles are excellent swimmers, the swimming behavior is studied with a high speed video camera system. The structural properties of legs are also studied by an optical microscope and scanning electron microscope. Some functional principles underlying leg design are revealed.
Moven Material
Paper
Technical Report
  • Toshiyuki UENO , Toshiro HIGUCHI, Eric SUMMERS
    原稿種別: Technical Report
    2006 年 18 巻 1+2 号 p. 54-57
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    We have been proposing a magnetic force control method using the inverse magnetostrictive effect of magnetostrictive materials. With a parallel magnetic circuit consisting of iron yokes and permanent magnet, the magnetic force exerting on the yoke varies with the mechanical stress applied to the magnetostrictive material. The characteristics of the magnetic force, such as stress-sensitivity and range of the variation, are mostly dependent on the material properties of the magnetostrictive material. In this paper, we investigate the potential of the Galfenol, with high piezomagnetic constant and high saturation on our proposing method. The comparison of the theoretical and experimental results of magnetic force clarifies the advantages of the Galfenol.
Review
  • Yoshitake NISHl, Yoshihito MATSUMURA, Shingo MASUDA , Keisuke TAKA ...
    原稿種別: Review
    2006 年 18 巻 1+2 号 p. 58-61
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    This paper describes mover materials successfully developed in 2005. They are compressive Sm-Fe alloy film and its composite multimorph mover devices. The composition dependence of magnetostriction was studied. The giant magnetostriction (GM) was found from 28 to 34 at%Sm. Furthermore, the largest compressive value of magnetostriction was 1400 ppm in a SmFe2.2 film prepared at 423 K of substrate temperature under 0.5 Pa of argon gas sputtering pressure. The high magnetostrictive susceptibility was also obtained in the bimorph composite GM device constructed with extensive (positive) Tb-Fe and compressive (negative) Sm-Fe alloys fllms.
Review
  • Shingo MASUDA, Yoshihito MATSUMURA , Yoshitake NISHI
    原稿種別: Review
    2006 年 18 巻 1+2 号 p. 62-64
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    The compound TbFe2 and SmFe2 are known to exhibit the largest positive and negative magnetostriction, receptively. Thin fllms prepared by magnetron sputtering process were obtained film structure showed by Thornton model. The change of this film structure was expected influence of magnetostriction properties. SmFe alloy thin films were prepared by D.C. magnetron sputtering process at different substrate temperatures from 323 K to 623 K and at different argon gas pressure of 0.5 and 0.8 Pa. A magnetostriction of the Sm-Fe alloy film increased with decreasing gas pressure on sputtering. The maximum value of magnetostriction over 1300 ppm at 1.0 MA/m was found in a Sm-Fe film prepared at 423 K of substrate temperature below crystallization temperature and at 0.5 Pa of argon gas pressure.
Paper
  • Teiko OKAZAKI, Yasubumi FURUYA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 65-69
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Two types of multi-ferroic actuator/sensor devices. i.e. (1) magnetically driven composite actuator and (2) multi-functional surface acoustic wave (SAW) sensor by MEMS are presented for intelligent/smart technologies. The large-scale robust composite actuator (1) is designed to combining the ferromagnetic property with superelasticity of shape memory alloy (SMA) because it can be driven with high speed as well as considerably large strain by applying a wireless magnetic field. The composite is reinforced by the superelastic fiber or lamellar of shape memory alloys (TiNi, CuAlMn) in the ferromagnetic metal(Ni, Fe) matrix. Secondarily, multi-functionally designed, multi-ferroic senor device of surface acoustic wave (SAW) is introduced. Piezoelectric LiNbO3(x-y cut) base materials are used. IDT has been produced by lithography. On the surface part between IDTs, environmentally active material films such as SMA, FSMA, magnetostrictive alloy etc. are formed by magnetron-sputtering. These results show the possibility of a new type of multi-functional composite actuator and sensor based on multi-ferroic effect.
Paper
  • Takashi TODAKA, Yuji TSUCHIDA , Masato ENOKIZONO, Tsugunori KANADA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 70-73
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Ferromagnetic shape memory alloys have been developed by means of the melt spinning technique. The alloys are multi-functional materials, which have both the ferromagnetic property and shape memory property. We have focused our interest on Fe-Mn-Si based alloys, which are nonmagnetic material due to high manganese content. To improve ferromagnetic function, we have investigated to add rare earth elements and compared effects of Nd, Sm, Dy, and Ho in detail. The results show that the ferromagnetic functions can be improved by adding up to 1wt% rare earth elements. The additions worked to shift the Curie pint upward and to increas the residual saturation magnetization even after heat-treatment. The heat-treatment has been optimized to obtain the largest saturation magnetization and the perfect shape memory recovery.
Paper
  • Tsugunori KANADA, Katsuou YAMASAKI , Keitaro MIYAGAWA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 74-77
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    A new drive system using shape memory alloy(SMA) wire is introduced in this paper. The system is designed for a car with the shape recovery force of SMA wire. A loop of SMA wire processed to memorize the straight line is set around a large pulley and a small one. When the wire around the small pulley is heated partially with hot vapor, it generates the recovery force at the heated part of the wire and turn to the torque to run the pulley. A bundle of wires can produce larger torque and it is possible to make SMA heat engine with the torque. In this study, the factors related to the rotational speed, such as diameter of small pulley, wire loop number and room temperature, were investigated. Moreover the relationship between wire loop number and torque too. It shows that the factors plays very important role. The speed of the unmanned car reached a few kilometers per hour.
Mech and pryto
Paper
  • Takanori TAKENO, Hiroyuki MIKI, Yutaro HOSOI, Toshiyuki TAKAGI, Takes ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 78-81
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Structure and electrical properties of cobalt-containing amorphous hydrogened carbon films were investigated. Cobalt doped films were prepared by RF discharge of methane gas and DC co-sputtering of the cobalt target. The structure of the films was examined by transmission electron microscope (TEM) and Raman spectroscopy. Cobalt atoms form the grain and they are well dispersed in carbon matrix. The results of Raman spectroscopy show the structure of the carbon is amorphous. But the spectra of the samples after the heat treatment shows different. D peak position was shifted toward the lower frequency and this indicated the change of carbon chemical bonding state. Room temperature resitance and temperature dependence on resistance were also investigated. Resistance at room temperature decreases drastically with increase of metal concentration. Temperature dependence on resistance with the concentration variation of the samples indicate , that electrical properties of the samples with strongly effected by the concentration of embedded cobalt.
Paper
  • Takeshi KONNO, Mikihiko KOBAYASHI, Mitsuru EGASHIRA, Kazumichi MACHIDA ...
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 82-85
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    We have developed a probe manipulation technique, and fabricated apparatus that can manipulate and weld fine metal objects of 10 μm to 100 μm. They are caught with a tungsten probe by applying voltages less than 100 V to the probe. Fine metal objects are welded by contact welding and non-contact welding using the tungsten probe as an electrode after it was set in place. Contact welding corresponds to resistant welding, and non-contact welding corresponds to arc welding. Here, we introduce the application of a smart probe for probe cards. Noble metal alloy particles of 40-75 μm are welded at the top of a rhenium-tungsten alloy wire of 125 μm in diameter using the apparatus. The composite will be the smart probe by sharpening the tip. The smart probe will improve the performance of the probe cards. The tip of the noble metal alloy reduces the contact resistance and will extend the life of the probe card. A cross section of the welding interface between the wire and the particle is examined by an SEM and an EDX.
Paper
  • Mikihiko KOBAYASHI, Takeshi KONNO, Mitsuru EGASHIRA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 86-89
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Particle assemblage by probe manipulation is a built-up process to fabricate microstructures. We investigated the probe manipulation method featured by applying voltages to the probe to control the adhesion force. Two types of probe are fabricated. One is a monopole probe and the other is a dipole probe. The former is composed of a needle-like metal wire, and the voltage is applied between the probe and the external electrode like a metal substrate. The latter is composed of a needle-like electrode and a stainless tube arranged concentrically. The tip of the monopole probe was shaped hemispherically by insulating resin. The monopole probe can catch fine particles of 10 μm to 100 μm on the metal substrate, while the monopole probe can catch both conductive particles and dielectric particles without the restriction of substrates. The particles jump up to the tip of the probe and adhere. The features of the two probes are compared.
Review
Paper
  • Takafumi ONISHI, Toshihiko SHIRASHI, Shin MORISHITA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 95-98
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Bone mass is increased by adequate exercises. This phenomenon has been mainly explained as chemical reactions of bone cells in the biochemical field. Because the cells can be considered as structural systems composed of mechanical components of cytoskeletons and focal adhesions in the view of mechanical dynamics, the mechanical properties of the cells can affect the response of them to the mechanical stimulation such as the variation of the bone mass to the stimulation. In this study, mechanical properties of an osteoblast, which is one of bone cells, were measured experimentally. The tensile and viscoelastic properties of the cell were measured with tensile and creep tests. The tensile load could be obtained with measuring the deflection of a micropipette, whose spring constant was calibrated after each test. As a result, the relationship between the tensile load and the elongation of the cell was obtained. In addition to the tensile test, the increase of the elongation of the cell was measured keeping the tensile load as constant in the creep test. Using these experimental results, a three-element model of the cell for viscoelasticity was introduced and the value of each element was identified.
Paper
  • Satoshi KISHIMOTO, Norio SHINYA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 99-102
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    A metallic closed cellular material for smart materials has been fabricated by sintering of metal coated powder particles. Powder particles materials coated with nickel-phosphorus alloy layers using electro-less plating were pressed into pellets (green pellets) and sintered in vacuum at high temperature using an electric furnace or a spark plasma sintering system. Then a metallic closed cellular material containing organic material was then constructed. The cross-sections of the specimens were observed using the scanning electron microscope. The compressive and damping tests were carried out to measure the mechanical property of this material. The results of the compressive tests show that this metallic closed cellular material has a long plateau region and high-energy absorption. In addition, the specimens sintered at different conditions have different mechanical properties. The compressive strength would increase due to the increasing of cell wall thickness. The results of the damping tests show that the internal friction of this material is same as that of pure aluminum.
MR
Paper
  • X.M. DONG, Miao YU, C.R. LIAO, W.M. CHEN
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 103-106
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Due to the nonlinearity, time-delay of magneto-rheological (MR) suspension system, application of linear feedback control strategy is limited. Therefore, a human-simulation intelligent control (HSIC) for MR suspension is proposed and studied. To determine the time-delay magnitude of MR damper, an experimental apparatus is founded and the response time is tested for various operating conditions. The results show that the response time of MR damper is about 30 ms that cannot be ignored in real time control. A hybrid Taguchi genetic algorithm (HTGA) is adopted to tune the parameters of the HSIC controller. To verify the feasibility of our approach, road test are carried out. The results show that after some threshold parameters are optimized by HTGA, HSIC can achieve better ride comfort and stability compared to passive suspension.
Paper
Paper
  • C.R. LIAO, M, YU, H.H. ZHANG, W.M. CHEN, S.L. HUANG
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 113-118
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    In this paper, the Eyring constitutive model parameters have been identified via minimization of the error function defined as error sum between shear stresses from experimental tests in laboratory of Chongqing University and shear stresses depicted the Eyring constitutive model. Authors have theoretically set up flow control equations for magneto-rheological (MR) fluids in annular channels using the Eyring constitutive model and N-S equations in hydrodynamics. The velocity profiles of MR fluids through annular channel are obtained by means of flow control equations mentioned above. In accordance with piston velocity and annular channel geometrical parameters of MR fluid shock absorber, MR shock absorber performances have been predicated by means of analytical methodology developed in this paper. In the light of technical requirements of front suspension of Chanan star minibus, a MR fluid shock absorber, which is designed and fabricated in Chongqing University according to design method presented in this paper, has tested by electro-hydraulic servo vibrator and its control system in National Center for Test and Supervision of Coach Quality. The experimental results reveal that the analytical methodology and design theory are reasonable.
Paper
Paper
  • Yosuke SATO, Toshihiko SHIRAISHI, Shin MORISHITA
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 123-126
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Magnetorheological (MR) fluids can vary their rheological characteristics by applying magnetic field strength and have been applied to various kinds of devices. In this study, an MR fluid was applied to an engine mount. This MR engine mount can not only mount an engine to insult its vibration, but also absorb impact force applied to drivers when a car collides in an accident. As an engine is the heaviest component of a car, the impact force can be reduced by controlling the damping force of the engine with the MR engine mount. In order to design the MR engine mount, we measured the typical characteristics of the MR fluid, as which we obtained the relationship of the shear stress to the flow rate, the magnetic flux density and the gap length of the MR fluid flowing, and the response time to the magnetic flux density. Using these experimental results, the MR engine mount was designed to satisfy the desired controllable range of the damping force.
Paper
  • Kosuke NAGAYA, Zhehong JIN, Suguru MIWA, Zhichao CHEN
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 127-130
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    A new-type tire is presented, in which there is no air leakage when nails break the tire. The broken part is repaired automatically by its self-repairing mechanism. The self-repairing sealant layer is consisting of two rubber sheets with lattices inside. Polymer particles are inserted in the lattices in the sealant. Coolant fluid diluted with water is inserted in the polymers umiformly, and so the polymer particles expand with water diluted coolant fluid, and become gel. Hence, they stop air leakages in the tire. The sealant is pasted to the inside wall of the tire. A method of making the sealant is developed, and vibration characteristics of the tire with the sealant are investigated.
hM
Paper
Paper
  • Hiroyuki KUDO, Elito KAZAWA, Toru SASAKI, Akinori IWAMOTO
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 140-143
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    A spatial resolution of real-time bioradiography system was closely measured using PDMS (polydimethyl siloxane) microfluidic chips with microchannels down to 20um wide. We measured the spatial resolution by comparing line width of a chemiluminescence image and a beta-ray image. Both images were obtained using identical microchannel. Using our method, a spatial resolution can be measured within an equal condition to actual observation. In addition, the spatial resolution was improved upto 20um FWHM(Full Width at Half Maximum), which is 50 times better than that of conventional method. Owing this method, we experimentally confirmed that b-ray scattering degrades the spatial resolution of the β-ray image.
Paper
  • Gang LI, Xinwei WANG, Lihua SHI
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 144-151
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    In this paper, Empirical Mode Decomposition (EMD) is employed to eliminate noises existing in experimentally acquired ultrasonic guided Lamb wave signals. The detailed procedures are provided and several examples involving both narrowband and wideband signals are given to show the validity of the proposed de-noising method. Comparisons are made with the results obtained by the well-known Wavelet method. It is found that both EMD-based and Wavelet-based de-noising methods can yield acceptable results. It is also found that EMD-based de-noising method can separate noises from noise-polluted signals more efficiently due to its adaptive nature in the de-noising process, and that less empirical information is required as compared with the Wavelet-based de-noising method. Based on the results reported herein, one may conclude that EMD-based de-nosing method can be effectively used to get a clear and significant response signal, an important step in the area of structural health monitoring. Further research should be made to establish a reliable criterion for separating a useful IMF from noise components in general cases.
Paper
  • Jinhao QIU, Gael SEBALD, Makoto YOSHIDA, Daniel GUYOMAR, Kaori YUSE
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 152-157
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Active, semi-passive and passive noise isolations of a plate bonded with piezoelectric elements were studied and their effectiveness is compared. The noise is generated by a loudspeaker inside a box and transmitted to the outside through the plate. The frequency of the noise was swept around the first resonance mode of the plate. The results show that the damping effect at the first resonance mode reaches 7.4dB with semi-passive technique, 13.5dB with active technique and 8.2dB with passive technique. The influence of sweeping speed on the control performance of each approach was investigated, and a large decrease of performance was observed for semi-passive control (70% of decrease) at the sweeping speed of 200Hz/sec. A decrease of 30% is observed in case of active control, whereas there is almost no decrease of performance with passive technique. Increasing the excitation level leads to non-linear behavior of the plate inducing a much lower damping. The influence of excitation level on the control performance of three approaches was investigated. The results show that all these three techniques are easily affected by nonlinearity.
Paper
Paper
  • Yves Bernard SUNYOTO, Adel RAZEK
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 162-165
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    This work concerns the study of bone regeneration between two parts of a cut bone that occurs while the elongation of such bone. In the actuation that can move one part of the bone with respect to the other the displacement will be discontinuous consisting of very small steps to maintain a daily given very small gap between the two bone parts. The forces required are very weak because they only stretch the tendons that are elongated in few displacements. The actuator described in this paper fulfils given specifications and is of few centimetres dimensions. It is a piezoelectric actuator so that the use of magnetic resonant imagery could be possible even if the patient wears such actuator. The principle of displacement is inchworm and its total range is only determined by the length of the rotor (moving part). A prototype has already been achieved. This paper deals with the design and the characterization of this actuator.
Paper
  • Guomao YANG, Wei REN, Georges AKHRAS, Binu MUKHERJEE
    原稿種別: Paper
    2006 年 18 巻 1+2 号 p. 166-169
    発行日: 2006年
    公開日: 2010/02/11
    ジャーナル フリー
    Some dielectric elastomers produce large electric-field-induced strains that can be used for electromechanical actuation. When an electric field E is applied on an electroactive polymer film electroded on both sides, the film is subjected to a stress T due to the electrostatic force (Maxwell stress) and this causes it to deform, producing a strain in the plane perpendicular to the applied field. We have measured the transverse strain responses of silicone (Dow Corning HS III) Maxwell stress actuator samples of different sizes over a wide displacement range and a frequency range from DC up to 100 Hz. The static and dynamic strain responses of the materials to a variety of driving electric flelds such as step fields, AC fields and DC bias fields have been measured as functions of amplitude and frequency. The effect of a mechanical tensile pre-load on the transverse strain has also been investigated. A pre-load initially causes an increase in the strain but the strain decreases when larger values of pre-load are applied. Numerical finite element simulations of the material using the commercial software package ANSYS and suitable models of hyperelasticity provide good agreement with most of our observations on the electric field and pre-load dependencies of the transverse strain.
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