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Published: September 15, 2006
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Article type: Index
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A1-A4
Published: September 15, 2006
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Joji UCHIYAMA, Kimihiko NAKANO, Takashi SAITO, Toshitaka YASUDA, Souic ...
Article type: Article
Session ID: 601
Published: September 15, 2006
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The cooling of brain tissue has been recognized to effectively suppress epileptiform discharges (EDs) and local brain cooling using a thermoelectric device has recently gained much attention since it has a potential to be a viable alternative for a surgical resection of epileptogenic foci. However, when considering implantable systems, several problems such as the electric power supply or the arrangement of the whole system in the body have to be resolved. Then, the authors devised a new cooling device with a heat pipe attached to the thermo-electric chip and also examined the performance of this device through the experiments using a phantom and animal studies. The results indicate the proposed device has enough cooling performance to suppress EDs.
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Kazuto TAKASHIMA, Kiyoshi YOSHINAKA, Ken IKEUCHI
Article type: Article
Session ID: 602
Published: September 15, 2006
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We have developed catheter simulation system in blood vessels for training of young physicians. In this study, we evaluated the necessary criteria for an effective tactile interface. The model of the guidewire was constructed with viscoelastic springs and segments as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness and damping of the vessel wall. This simulator should improve the safety of the intravascular surgery.
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Shosaku KINOSHITA, Yoshinori KAWASAKI, Takeshi KIZUKA, Ryutaro KANAMAR ...
Article type: Article
Session ID: 604
Published: September 15, 2006
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Operations such as valve substitution and coronary-artery bypass surgery have been performed for patients having trouble in their hearts. It is said that open heart operations for such cases of disease exceed 40,000 in Japan. Rib spreaders, operation tools, are used for spreading patient's chest ribs right and left and holding. Several type of conventional rib spreader involve many problems to be improved from the practical point of view. In this report, new type rib spreaders with the aim of reducing patient's physical load, the number of doctor and time required for operation are presented. In addition to tools, the new type of bone fixation device developed is introduced here.
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Yoshimitsu MATSUURA, Toshiyuki UENOYA, Yasuyomo UETSUJI, Eiji NAKAMACH ...
Article type: Article
Session ID: 605
Published: September 15, 2006
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Our health monitoring system (HMS) consists of 1) the painless blood extraction, 2) the handy type automatical blood extraction, and 3) the continuous measurement in blood sugar level by insulin administering. In this study, a vacuum extracting type device for the blood sugar measurement is newly developed, which employ a handy type automatical blood extraction system, such as a mobile HMS for the diabetes patients. The vacuum extracting blood unit, which is built in this vacuum extracting type HMS device, consists of a) the puncture part, b) the extraction part, and c) the base part, and succeeds in extracting 12.7μl of human blood within 2 seconds.
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Tatsuro KURODA, Hidetake YAMAMOTO, Kazuyoshi TSUCHIYA, Yasutomo UETSUJ ...
Article type: Article
Session ID: 606
Published: September 15, 2006
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In this study, an automatic blood vessel searching system (BVSS) is newly developed, which is built in the Health Monitoring System (HMS) and the drug delivery system (DDS) to extract the blood, evaluate the blood sugar level and inject the insulin for the diabetic patients. Main subjects of this BVSS development are 1) a transmittance photo imaging of the finger by using the LED light as a near-infrared light source with peak wave length of 870nm, and 2) an image processing to detect the location of the center of blood vessel. To estimate the depth of blood vessel, the lens focal method was applied to the BVSS. To confirm the possibility of the method, we carried out experiments using blood vessel phantoms that consist of a cylindrical blood region (Teflon tube) and skin tissue (silicone rubber). The blood region was 0.6mm in diameter and filled with human blood. The experimental results demonstrated the estimated depth from each image corresponding to given depth exactly and confirmed the validity of BVSS.
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Akihiro Soeta, Takuji Koike, Sayuri Murakami, Kyoji Homma
Article type: Article
Session ID: 607
Published: September 15, 2006
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In this study, a new transducer for a minimally invasive hearing aid which directly vibrates the tympanic membrane was proposed. The transducer consists of a magnet and a small sized coil to vibrate the tympanic membrane. To evaluate the performance of the transducer, an artificial tympanic membrane model was made, and the vibration of the artificial tympanic membrane caused by the transducer was measured. The results suggested that the transducer generated the excitation force of more than 80dB SPL in terms of sound pressure in the wide frequency range from 0.25 to 10kHz. Regarding the response to the signal of the human voice, the transducer had a higher fidelity than conventional high-quality speaker.
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Atsushi NAKAYAMA, Kazunori HASE, Goro OBINATA, Norimasa ADACHI
Article type: Article
Session ID: 608
Published: September 15, 2006
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At present during clinical examination, physical therapists mainly use the Modified Ashworth Scale (MAS) to evaluate the severity of spasticity. However, MAS is a qualitative evaluation and the results depend on the therapist. The purpose of this study is to propose a modeling method for quantitatively evaluating the severity of spasticity. The proposed method uses the Independent Component Analysis technique and data from the pendulum test of the patients leg. The method estimates a model of spasticity system and its input signals.
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Kenichi ITOU, Masayoshi TAKEUCHI, Yuichi NAKAZATO
Article type: Article
Session ID: 609
Published: September 15, 2006
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This Paper describes research on pet robot of biped locomotion with short legs. Today, pet robots are increasing to be used in welfare field. Pet robots used in welfare field are requested to give elderly people to familiarity and enjoyment, comfort. One of objects that people feel familiarity and enjoyment, comfort is deformed animal of biped locomotion with short legs. In this study we searched for of elderly people liking which of the three pictures of deformed animal with the different length of legs, and liking either one of the two workings. This paper reports availability of pet robot of biped locomotion with short legs and consideration of working of this pet robot for prevention of dementia in elderly people.
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Tsutomu Matsumoto, Yasuyuki Shimada, Shigeyasu Kawaji
Article type: Article
Session ID: 610
Published: September 15, 2006
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It has been pointed out that the number of patients afflicted with lifestyle diseases such as hypertension, diabetes and hyperlipemia is rapidly growing. It is well-known that these diseases stubbornly resist treatment. Therefore prevention is more important than cure. And it is known that an improvement eating habits (alimentary therapy) is effective for prevention or the treatment of the lifestyle disease. Creating well-balanced meals for patients require specialized knowledge about nutritional effect, alimentary therapy and/or prophylactic diet. However, all of people can not been given dietary advice by dietitian. Moreover information on food is required to take the best care of the health. This paper describes a designing and implementation of alimentary therapy assist system. The system records client's meal history and provide the client with healthy menu based on the meal history and individual taste.
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Masahiro TODOH, Shigeru TADANO, Hiroyuki KITAGAWA
Article type: Article
Session ID: 611
Published: September 15, 2006
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It is often difficult for handicapped people using the electric-powered wheelchairs to maintain their posture against external forces. Therefore, it is important to reduce the instability in driving the wheelchair under the various road conditions. In this study, the level holding seat mechanism available for the general electric-powered wheelchairs has been proposed. In order to occur the torque by the driver's weight and the range of inclination angle, the level holding seat was constructed by the link mechanism with the linear actuator. A prototype model of level holding mechanism was made practically. The effect of the proposed mechanism was evaluated by the running tests with electric-powered wheelchair. As the results, the stability of the driver and wheelchair system increase by this level holding seat mechanism.
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Toshihiko YASUDA, Naoyuki KAWAKUBO, Daisuke FURIKADO, Katsuyuki TANAKA
Article type: Article
Session ID: 612
Published: September 15, 2006
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We have developed a one hand drive wheelchair with assist functions for running. In previous researches, an assist unit was proposed. However, because rubber rollers always grip tires, the old-model assist unit yields the running resistance, which cannot be ignored. In this paper, the new assist unit, which is operated by rink mechanism, is proposed. This assist unit is possible to contact rubber rollers with tires and to release rubber rollers from tires. Therefore, when none of assist functions is needed, rubber rollers leave from tires and no running resistance exists. On the other hand, rubber rollers grip tires, when assist functions are needed. Results of experiment show the advantage of newly proposed assist unit.
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Tao LIU, Yoshio INOUE, Kyoko SHIBATA
Article type: Article
Session ID: 613
Published: September 15, 2006
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A wearable sensor system for gait analysis is presented, which is composed of a combination of motion sensor modules and a 6-aixs reaction force sensor. Experimental study was implemented to estimate orientations of leg segments and measure foot reaction forces during walking. Based on the quantitative motion and force analysis, this system can detect the following gait phases from clinical study: initial contact, loading response, mid stance, terminal stance, pre swing, initial swing, mid swing and terminal swing.
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Nobuyoshi MORITA, Yuki HATAKEYAMA, Junichi TAKANO, Bin FENG, Takashi M ...
Article type: Article
Session ID: 614
Published: September 15, 2006
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A new water insole including water in the insole was developed. The positions, sizes, number and shape of some dams and some orifices in the insole control a flow of water in this insole. This insole have two functions, one is the shock absorption function when the heel lands, and the other is the press function to the arch of a foot part. For the water insoles designed and manufactured, some experiments were made as the capacity of compression pressure, the freezing characteristics and the static and the dynamic pressure distribution of a foot part.
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Hiroshi OKAMURA, Jun MATSUSHITA, Masao ISHIHAMA
Article type: Article
Session ID: 615
Published: September 15, 2006
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The development of the walking assist device system is worked on not only the solution of engineering technology, but also the several view point areas. It is important to study the system on the integration with the medical science approach, the community-based barrier-free environment, the social communication network system and so on. It is discussed how system is better for the effective utilities of the walking assist device, mainly town mobility of welfare mobility and barrier free system.
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Masuji NAGATSHI, Keiji IMADO, Atsuyoshi MIURA, Tsuyoshi AKIYAMA
Article type: Article
Session ID: 616
Published: September 15, 2006
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It is said that stretching the lower limbs by flexing ankles are good for health. So many kinds of stretching goods have been developed. But most of them are not take the blood flow rate in the lower limbs into account. In the previous report, we have reported that the blood flow rate was significantly affected by the angular velocity of the pedal of stretching device. But the magnitude of the torque of the ankles was not evaluated. This study was carried out to investigate the torque change of ankles with pedal angle. Experimental results showed that torque of ankles were varied from persons to persons. So this device can be used for a quantitative evaluation of the flexibility of lower limbs.
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Kazuto MIYAWAKI, Takehiro IWAMI, Goro OBINATA, Mineyoshi Sato, Yoich S ...
Article type: Article
Session ID: 617
Published: September 15, 2006
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According as our society again, assist machines begin to needed for persons of advanced age. We research and develop a fitness apparatus according to requirement of elderly people. Proposed apparatus which is consisted of a rowing machine and Functional Electrical Stimulation (FES) can exercise every part of muscle for the persons of advanced age. The rowing mechanism was developed to train rowers. The rowing exercise can train legs and upper effectively. Move over FES can assist the exercise of the leg by using surface electricity stimulus. It confined that the investigated apparatus trained the muscles of the person of advanced age effectively and could cancel exercise shortage.
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Nobuyoshi MORITA, Katsuhiko YOKOTA, Noriyuki SUZUKI, Bin FENG, Takashi ...
Article type: Article
Session ID: 618
Published: September 15, 2006
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This paper deals with a new bed for a human body supported by multi-planes moved by air control. Air-cells and rubber-tubes are located lengthwise and sideways respectively, and wood pins with plane urethane foam are located on a point of the intersection of air-cells and rubber tubes. When pressures of the air-cells and rubber-tubes increase, the pins are moved up and plane urethane foam push up the back of a human body. It is able to change the magnitude of the pressure and the pressure distribution to the back by controlling the pressure of the air-cells and rubber-tubes. This bed is useful for the prevention of the bedsore.
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Takaaki SATO, Hitoshi MIYAKE
Article type: Article
Session ID: 619
Published: September 15, 2006
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The muscle spindle that is a sensor in vivo has an interesting structure. The combination of the actuator and the sensor is related to the time base range of this sensor. This can be developed as a new sensor referring to the structure. In this study, a load cell and a linear stage were combined to develop a prototype tensiometer.
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Ryuichi YAMANE, Akihiro OKA, Fuyuhiko MORITA, Kouhei MURASE
Article type: Article
Session ID: 620
Published: September 15, 2006
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A technique of motion capturing using digital video (DV) cameras was proposed to measure the time dependent changes of human posture. This system was consisted of several couples of the image acquisition, the object extraction, and the three-dimensional coordinates restoration. There have distributed processing on the network. Therefore, the re-composition of sysytem and the system of processing of faster is easy. The result of recognition rate in changing the lighting in the manufacturing cell, targets which put on the working uniform were able to captured. The result of spatial recognition showed that the maximum error was 10mm.
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Takuji Ishikawa, Masateru Hota, T.J. Pedley
Article type: Article
Session ID: 748
Published: September 15, 2006
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The interaction between two swimming Paramecium Caudatum is investigated experimentally. The motion of cells is restricted between flat plates. We observed avoiding and escape reactions as well as hydrodynamic interactions. The results show that the cell-cell interaction is mainly hydrodynamic and the biological reaction is a minor incident. We also performed numerical simulations by a boundary element method. P. Caudatum is modelled as a squirmer with the surface velocity measured by a PIV technique. Hydrodynamic interactions observed in the experiment agree well with the numerical simulations, so a squirmer model is appropriate for expressing the motion of P. Caudatum.
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Yoshitaka KAMEO, Taiji ADACHI, Masaki HOJO
Article type: Article
Session ID: 750
Published: September 15, 2006
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Cancellous bone tissue adapts its mass and structure to functional stress by trabecular surface remodeling. Bone remodeling is accomplished by cellular activities under the influence of mechanical stimuli. Due to evidences emerging from recent researches, the hypothesis that osteocytes sense interstitial fluid shear stresses acting on the membranes of their osteocytic processes is gaining credibility. Our objective is to establish a computational bone remodeling model based on this hypothesis. First, the load-induced fluid shear stress in a trabecula considered as a poroelastic material was calculated using a finite element method. Second, the spatial and temporal regulation of the trabecular structure was simulated by taking fluid shear stresses to be the driving force for bone remodeling. These results suggest that our computational simulation could quantitatively express the functional adaptation of a trabecula.
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Mayumi SHIMIZU, Toshio TSUTA, Daisuke MUNAKATA
Article type: Article
Session ID: 751
Published: September 15, 2006
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Masayuki TANAKA, Seiichi KOSHIZUKA
Article type: Article
Session ID: 752
Published: September 15, 2006
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The Red Blood Cell (RBC) keeps a biconcave shape in a static fluid and deforms to a parachute shape in a flow. RBC membrane has been modeled by two kinds of springs coupled with fluid dynamics using a particle method. RBC shapes in a static fluid and a flow were simulated qualitatively. In this study, the Deformation Index of a flowing RBC is compared with the experiment. The calculation result shows good agreement with that of the experiment.
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Michito AKAGIRI, Hisasi TANIGUCHI, FUYOU Liang, Shinichi FUJIMOTO
Article type: Article
Session ID: 753
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The left ventricle (LV) hemodynamics is great important in determining the condition of the whole human circulatory system. It is known that the function performance of LV is determined by the intraventricular fluid dynamics under the influence of the shapes of LV. However, flow patterns in LV are always extremely complex and difficult to be fully understood by medical measurements. Therefore we build various 3D-LV models (1-cycle) from Ultrasound images and devise a multi-scale computational method with a three-dimensional (3D) computational fluid dynamics (CFD) solver. From those result, we compare how the LV of a person changes as time passes quantitatively and study it.
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Takashi KATOU, Toshio TSUTA, Asako TOKUMINE, Kouichi UTANOHARA
Article type: Article
Session ID: 754
Published: September 15, 2006
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This paper presents a creep-relaxation remodeling analysis of coronary blood vessel with atherosclerosis, subjected to vascular expansion by balloon pumping pressure of the PTCA (percutaneous Transluminal Coronary Angioplasty), with or without stenting coodition
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Tomooku KOYAMA, Kuniharu OKA, FUYOU Liang, Hideo YOKOTA, Ryutaro HIMEN ...
Article type: Article
Session ID: 755
Published: September 15, 2006
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Most of the CFD-based studies have been focusing exclusively on some specific blood vessels or vascular segments under highly simplified physiological boundary conditions. The cardiovascular system, however, is a closed-loop system where hemodynamics is an integrated result of the complicated interactions and plays an important role in hemodynamic regulations throughout the system. Therefore, a multi-scale hemodynamic simulator capable to evaluate the circulatory system in a synthetical manner is thought to be able to provide a physiologically realistic evaluation on the circulatory functions. A baseline for such a hemodynamic simulator requires development of a global arterial-and-venous tree model on a basis of the blood vessel morphology of the vascular system as well as the vessel-specific biomechanical properties. In this paper we present some preliminary results of a recently established vascular system database, involving 375 blood vessel models of 263 arteries and 112 veins, which are built up based on the Voxel-Man 3D Navigator, and of visualized blood flow patterns in some vessels of the global arterial-and-venous tree model.
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Shigefumi TOKUDA, Satoshi SUGIYAMA, Takeshi UNEMURA, Marie OSHIMA
Article type: Article
Session ID: 756
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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It is an important issue how to reproduce properly an in vivo environment in hemodynamic simulation of living organism. In this paper, we focus on modeling of outflow boundary conditions taking account of peripheral vessel network. The network of cerebral arteries is modeled including the arteries and arterioles, whose sizes can not be resolved by MRA. The peripheral resistance, compliance, and impedance are treated by one-dimensional and zero-dimensional simulations of the network. The present method is applied to two patient-specific models with or without occlusion in the cerebral arterial circle of Willis. As a result, particularly for the case with occlusion, the present method shows a significant difference in the flow rate of each artery and also improvement in flow distribution in the network comparing to the simulation with free-stream boundary condition.
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Masanori Nakamura, Shunsuke Sasaki, Takami Yamaguchi, Shigeo Wada
Article type: Article
Session ID: 757
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The paper proposes a method to analyze the wall thickness distribution of a blood vessel based on the uniform strain hypothesis. The wall is assumed to adaptively increase or decrease its thickness if the first principal strain is higher or lower than a threshold. The simulation is performed by interactively repeating the change in the wall thickness and the structural analysis. Analysis on the bifurcation shows that the final distribution of the vessel wall is not necessarily consistent with the strain distribution at the initial geometry. It is determined through the interactive process between changes in the vessel geometry and corresponding variations of the mechanical environments.
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Yuji AOKI, Akiyuki TAKAHASHI, Masanori KIKUCHI
Article type: Article
Session ID: 2027
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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Molecular dynamics simulations of interaction between a copper precipitate and a screw dislocation in iron were performed. The copper precipitates are considered as a harmful element in the neutron irradiation embrittlement of reactor pressure vessel steels. In the simulations, we applied a shear stress to atomic model, and gradually increase until the screw dislocation cuts through the copper precipitate. Then we investigated the critical resolved shear stress (CRSS) and the mechanism to break away from the copper precipitate.
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Masayuki KAMAYA, Koji FUKUYA, Takayuki KITAMURA
Article type: Article
Session ID: 2028
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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Since the grain sliding induces the grain boundary deformation and irradiation assisted stress corrosion cracking, the resolved shear stress (RSS) for grain sliding is an important factor. In this study, the RSS was evaluated by using three-dimensional polycrystalline bodies consisting of 2000 grains generated by a Monte Carlo method. Elastic finite element analysis was performed and the slip line angle at the surface and RSS were calculated. The frequency of slip angle distribution consisted with experimental results. The RSS tended to deviate from that obtained in homogenous stress condition due to constraint caused by adjacent grains.
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Yoshihiro KUBOTA, Ryosuke MATSUMOTO, Noriyuki MIYAZAKI
Article type: Article
Session ID: 2029
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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In recent years, nano-crystalline materials have attracted many researchers' attention, but the fracture mechanism has not been fully clarified. In a molecular dynamics (MD) simulation, grain size and crystal orientation can be chosen, and their effects on the mechanical properties of nano-crystalline materials can be evaluated clearly. However, the accuracy and computational time of MD simulation depends on its interatomic potential. In our previous research, it is confirmed that the Hybrid potential method, which connects FS potential and MEAM potential by the use of Handshake method, provide the high reliable results in short computational time. In this paper, the crack growth behavior analysis in nano-crystalline Fe by the use of Hybrid potential is demonstrated, and the grain-size and strain-rate dependency of fracture behavior is clarified.
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Keisuke AZUMA, Masato NAITO, Yoshihiro TOMITA
Article type: Article
Session ID: 2030
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The most typical characteristic of the present model is that it consists of eight standard models with Langevin springs and a dashpot obeying strain-rate-dependent response. The computational simulations employing the constitutive equations clarify the mechanisms of hysteresis loss and the strain-rate-dependent nature of the response of rubber. We employed the homogenization method and proposed constitutive equation to correlate the micro- to macroscopic deformation behavior of Carbon-Black filled rubber. Representative computationally predicted and experimental results are compared to evaluate the adequacy of the present simulation.
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Masanori KIKUCHI, Shogo SANNOUMARU
Article type: Article
Session ID: 2032
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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Thickness effect is studied experimentally. At free surface of the specimen, shear lip fracture pattern appears, though dimple fracture pattern is observed inside of the specimen. The area of shear-lip fracture changes due to the change of the specimen thickness. In this study, experimental study is conducted by changing specimen thicknesses. Fracture surfaces are precisely observed using SEM, and dimple patterns on them are observed. At the free surface, very narrow no-void area is observed. FEM simulation is carried out using Gurson's constitutive equation. It is found that shear-lip type fracture is simulated near free surface area by this method. The results show similar tendency with the experimental observation.
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Koji FUJIMOTO, Tsunenori YAMAMOTO, Tadashi SHIOYA
Article type: Article
Session ID: 2033
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The box-counting method has been applied to the evaluation of fractal dimensions of the fracture surfaces by using the gray scale values of the bit map images of SEM (scanning electron microscope) photographs. As specimens, gray cast iron (FC200) was adopted and the effect of the fracture mode (brittle or ductile) on the fractal dimensions of the fracture surfaces was investigated. The fracture mode was controlled by changing the temperature at the fracture tests. It has been clarified that the fractal dimension changes considerably with the magnification of SEM in the case of brittle fracture comparing with the case of ductile fracture.
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Akira TOYOTA, Yasufumi IMAI, Akihide SAIMOTO, Fumitaka MOTOMURA
Article type: Article
Session ID: 2034
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The behavior of wing crack growth influenced by free boundaries is studied. Compression of a plate with angled crack induces the propagation of wing cracks which grow almost parallel to the axis of compression. The mode- I stress intensity factor at the wing crack tip increases when the crack grows near a free boundary. In this study, the behavior of fracture under single axial compression of transparent material was investigated. A simulation of crack propagation was conducted for various cases in which the distance between free boundary and the location of initial crack and the crack inclination are different. The compression test using PMMA plates with centric and eccentric saw flaw were also demonstrated.
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Fumitaka MOTOMURA, Yasufumi IMAI, Akihide SAIMOTO
Article type: Article
Session ID: 2035
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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3D finite element analysis of thermo-elasitc problem was performed to relate between the crack front geometry and the crack growing velocity in a thermal stress cleaving. In a stable crack growth, the crack front geometry through a plate thickness becomes so as for stress intensity factor to distribute as much same value along a crack front. The faster a crack growing velocity, the wider a crack front leaves from a center of heat source to show stronger stress singularity. Analyzed result explains well the experiments.
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Satoshi TSUKIOKA, Tadahiro HYAKUDOME, Atsutoshi MUTO, Yasuhiro FUJITA, ...
Article type: Article
Session ID: 2036
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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Energy storage is an important technology for all equipment because environmental pressure is high, the temperature is 5 degrees Celsius or less, and it is unsuitable to the chemical reaction of the deep ocean. As for manned submersibles and unmanned vehicles, the necessary amount of electric power is enormous compared with mooring systems. Proton exchange membrane fuel cells which directly uses energy from the oxidation and reduction process to maintain the flow of electricity, closes up as new energy source for deep ocean vehicles instead of batteries. With normal temperature and normal pressure, hydrogen and oxygen exist as a gas. Recently, storing hydrogen with the alloy (called a metal hydride) came into practical use. The alloy can store hydrogen at low pressure and it is controlled quite simply. This paper presents optimal design of pressure housing to store metal hydride inside by finite element method and strain results obtained by high pressure tank test.
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Haruo Sakamoto, Akihiro Takebayashi
Article type: Article
Session ID: 2037
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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In Japan, with the recent increase in wind power generator installations, the incidence of lightning damage to FRP blades is increasing. Lightning damage is a significant issue in Japan since lightning in Japan seems severer than that in Europe or the US. To resolve this problem, the Kochi University of Technology received a request in 2002 from the Kochi prefectural government to research for lightning protection. We conducted the impact electrical discharge experiment concerning the lightning fracture of the FRP blades, and were able to understand the fracture mechanism and to execute the lightning protection. This report describes the method of the metal coating to the FRP blades as the lightning fracture countermeasure and the result by the impact electrical discharge experiments.
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Masanari OKUDA, Masashi Mohri, Katsuyuki SUZUKI
Article type: Article
Session ID: 2038
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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When we evaluate fatigue strength of the welded joint of structures by FEM analysis, the mesh near the joint toe should be fine, and be same direction. On the other hand, the mesh to evaluate the behavior of whole structure should be coarse in order to lower calculation cost. Mesh superposition method is one of the multi-scale FEM, which superpose fine local mesh on coarse global mesh. In this paper, we applicated mesh superposition method to the evaluation of fatigue strength of the welded joint.
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Hiroshi OKADA, Kousuke ARAKI, Hiroshi KAWAI
Article type: Article
Session ID: 2039
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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In this paper, the development of a three-dimensional VCCM (Virtual Crack Closure-Integral Method) to compute the energy release rate and the stress intensity factor, for tetrahedral finite element is presented. Discussions start with the case of conventional hexahedral finite elements. Then, the VCCM for tetrahedral elements is derived. We considered energy to separate triangular shaped area which is a face of a tetrahedral finite element, as a crack extends by one element length. Then, it is shown that the energy can be derived from nodal crack opening displacements and forces. Thus, the crack parameters are computed. Present VCCM for tetrahedral finite elements will be an important tool to perform large scale fracture mechanics analyses.
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Hiroshi KAWAI, Hiroshi OKADA
Article type: Article
Session ID: 2040
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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In this research, we developed a method to generate a mesh with a 3-D crack of complicated geometry, such as a curved crack with an arbitrary shape, fully automatically. First, a representation of an arbitrary 3-D curved crack geometry is proposed. Then, a pre- and post-processing system is developed, and the effectiveness of the system is demonstrated for some crack geometry patterns.
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Kohsuke ARAKI, Hiroshi Okada, Hiroshi Kawai
Article type: Article
Session ID: 2041
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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A three-dimensional virtual crack closure-integral method (VCCM for quadratic tetrahedral finite element to evaluate the energy release rate and the stress intensity factor is being developed. Use of tetrahedral finite elements has became a sort of standard way in the analyses of three-dimensional complex structure/solid structure, due to the recent advancement of automatic mesh generation software for tetrahedral elements. In this paper, procedures to evaluate the fracture parameters and some numerical results are presented.
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Nobuyoshi TOSAKA, Koujiro OHKAWA
Article type: Article
Session ID: 2101
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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One numerical solution approach to identification analysis of distribution of elastic constants is discussed. In our inverse analysis, the meshless finite element method is used to determine displacements of an elastic body and the filtering algorithms are utilized to identify elastic constants of sampling points. Applicability of our method is shown through comparison of distributions on two-dimensional elastic constant given by the Kalman filter and the parametric projection filter.
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Ryuji ENDO, Nobuyoshi TOSAKA, Yoshitsugu KAWAKAMI
Article type: Article
Session ID: 2102
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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Variable parametric projection filter (VPPF) is proposed as inverse analysis procedure to identify structural damage. Parametric projection filter has known as one of effective filters in parallel with Wiener filter and projection filter. As the characteristics of the parametric projection filter, the regular parameter to assure the stable filtering process is including. The regular parameter has been given as a voluntary value corresponding to each inverse problem in the existing analysis concerned with inverse problem using filtering algorithm based on parametric projection filter. In this study, the procedure to give the regular parameter computationally in each filtering step is shown instead of a voluntary value. As examples of inverse analysis using the VPPF, structural damage analysis based on system identification was performed for a 3-story frame structure model. Effectiveness of the VPPF is shown though some numerical calculations.
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Sayo YAMAGUCHI, Kensaku NAKATANI, Shiro KUBO, Takahide SAKAGAMI
Article type: Article
Session ID: 2103
Published: September 15, 2006
Released on J-STAGE: August 01, 2017
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The passive electric potential CT method was applied to identification of plural delaminations in a composite material. The piezoelectric film was pasted on the surface of CFRP composite material subjected to three-point bending. The effect of the location of delaminations on electric potential on piezoelectric film was investigated. A hierarchical inversion scheme was proposed for identification of plural delaminations. Numerical simulations were made to investigate the possibility of identification of delaminations from electric potential on the piezoelectric film. It was found that it was possible to identify the delaminations by the present method.
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