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Published: September 04, 2004
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Shoichi YOSHIDA
Article type: Article
Session ID: 101
Published: September 04, 2004
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When constructing the bottom of aboveground oil storage tanks, the bottom plates are first laid out on the flat foundation, and they, then are joined by welding the joints in sequence. As the foundation is difficult to be made completely homogeneous over the bottom area, the settlement of the bottom plates is not uniform under liquid pressure. The depressions of the bottom plates are sometimes found at the first internal inspection which is usually made about 10 years after the oil storage. This paper presents plane strain finite element analysis for the localized bottom depression in aboveground oil storage tanks. Load-incremental, elastic-plastic large deformation analysis is carried out considering contact with the foundation. The relationship of the stress at the depressed bottom plate to the liquid pressure is discussed together with the deformation of the depression.
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Satoshi IGI, Masanori KAWAHARA, Kazuma KAWANO, Kazuyoshi SEKINE, Shin- ...
Article type: Article
Session ID: 102
Published: September 04, 2004
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Since the past decade, diagnostics evaluation method for the oil tank under ultra low cycle fatigue was continuously discussed at several committees in Japan High Pressure Institute (JHPI). This paper reports the summary of the activity of the committees toward the establishment of the method to estimate crack growth life under repeated large plastic loading. Crack growth behaviors under large cyclic plastic strains were examined experimentally under both axial loadings and bending loadings of a plate with a surface flaw. A series of three-dimensional FEM analyses was also carried out to obtain J-integral value for shell-to-annular joint with various crack sizes.
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Hai YUAN, Kazuma KAWANO, Kazuyoshi SEKINE, Hiroaki MARUYAMA
Article type: Article
Session ID: 103
Published: September 04, 2004
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The shell plate of oil storage tank is an important evaluating component in Fitness-For Service Assessment, because it is required to have an enough strength against to the static and dynamic pressure in case of operation and an earthquake. This paper reported the analysis results of stress occurred at the local thin areas (LTAs) of shell plate and the stress tendency has been investigated when LTAs is assumed as a rectangular area and its size as study parameters. The investigation results show that there is a tendency for stress ratio to be going up when the longitudinal length of LTAs lengthens gradually. But it is the opposite for the circumference, the stress ratio is going down.
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Hiroshi OHYA
Article type: Article
Session ID: 104
Published: September 04, 2004
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The finite element method is applied to the thermal buckling analysis of laminated composite shells of revolution under axisymmetric temperature field. The displacement field within each element is represented by Fourier circumferential components. The coupling effect of general laminates is considered in the stress-strain relation. The validity of the present method is demonstrated by numerical examples.
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Yasutomo KANEKO, Kazushi MORI, Hiroyuki YAMASITA
Article type: Article
Session ID: 105
Published: September 04, 2004
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A compressor blade of low aspect ratio is a typical shell-type structure and its natural frequency and vibratory stress are sensitive to a manufacturing tolerance. In designing a blade, the designer should take variation of the vibration characteristics into account, and evaluate vibratory strength of the blade. In this paper, variation of the natural frequency and vibratory stress of the blade is evaluated by the 1st order 2nd moment method in addition to CFD and FEM, and the calculated results are compared with measured ones. From the results, it is confirmed that the variation of the vibration characteristics can be predicted by the simple method proposed in this paper.
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Tetsuya NARISAWA
Article type: Article
Session ID: 106
Published: September 04, 2004
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Composite materials (fiber-reinforced plastics : FRP) have been contributed greatly to the weight saving of mechanical apparatus. In the engineering field, since the plate and shell components made by FRP are widely used, the lightweight design is brought to realization. Since FRP materials have different elastic properties depend on the fiber-directions, the vibration characteristics show complex phenomena. In this report, the first, the natural frequencies and natural modes of the slightly curved composite plates formed with angle play are estimated based on the shallow shell theory and the Rayleigh-Ritz method. The next, the influence of fiber-direction and eccentricity of curved plate on the natural frequencies and natural modes are discussed. The third, the prospects of vibration control of anisotropic curved plate with the modern control theory are showed.
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Nariyuki KAWABATA, Hisao FUKUNAGA
Article type: Article
Session ID: 107
Published: September 04, 2004
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This paper presents a technique of vibration control of CFRP structures based on the modal sensor and the modal actuator, using accelerometers as sensors and PZT elements as actuators. In order to suppress the vibration of large-scale flexible structures, a high precise measurement of vibration and also an efficient control are indispensable. In a design of modal sensor, accelerometers are placed on the optimal locations based on the minimization criterion of the observation spillover. A location of PZT actuators is also optimized based on the minimization criterion of control spillover, and further the control gain is determined by LQR control theory to consider both a state cost and a control cost. Experimental results using a cantilevered CFRP laminated plate demonstrate the validity of the proposed modal sensors/actuators as a foundation of CFRP structures such as shell structures.
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Hideharu ISAKA, Katsuyoshi SUZUKI
Article type: Article
Session ID: 108
Published: September 04, 2004
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The purpose of the present investigation is to design an active isolation control unit which attenuates transmission noise. Especially, the case where a shell structure diaphragm is applied to the control is investigated. At first, an active noise isolation unit is constructed with a flat plate and a piezoelectric vibrator connected by rod, which could be attached to a shell structure. The fundamental experiments of active isolation control are carried out in order to examine this actuator. The experimental results show that the transmission noise could be attenuated about 30〜40dB. And, it became clear that the actuator proposed by this research is effective to active isolation control.
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Shigeru AOMURA
Article type: Article
Session ID: 109
Published: September 04, 2004
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A cerebral contusion and DAI(diffuse axonal injury) are very important in a medico-legal case of the closed head injury. Over the years, many studies have been done to obtain better understanding on them, however, the precise causal mechanism is hot fully understood. Recently, computer analysis is becoming an important tool for the study of impact brain injury. In this report, the basic idea of the finite element analysis for studying cerebral contusion is illustrated and the verifying method to obtain valid skull-brain interface condition is discussed. Finally the result of ALE method are compared with the result of the cadaver test reported by Nahum.
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Shigeru AOMURA
Article type: Article
Session ID: 110
Published: September 04, 2004
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Recently, numerical analysis is becoming important tool for studying the mechanism of brain injury such as cerebral contusion or DAI. However, experimental data is still important because validity of the numerical method can be verified only by the experimental data of real world. A crash test was done by crashing an iron impactor on occipital region of physical human head neck model and intracranial pressure was measured. Next, another crash test was done on the double acrylics cylinder container filled with water which realized human head structure simply and relative motion between both containers was observed by using a high-speed camera. These results can be used for further development of Finite Element modeling and analysis.
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Shinsaku ZAMA, Minoru YAMADA, Haruki NISHI, Ken HATAYAMA, Masahiro HIR ...
Article type: Article
Session ID: 111
Published: September 04, 2004
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The 2003 Tokachi-oki earthquake caused the severe damage to oil storage tanks by liquid sloshing. Especially at Tomakomai, two tank fires broke out and six floating roofs sank. Seismograms showed that long-period ground motions were predominant and duration became longer when the seismic waves propagated into the Yufutsu Plain, where Tomakomai is located. Sloshing wave heights (Wh) for all tanks were calculated by the two-dimensional response analysis. It was found that the estimated Wh exceeded 3m at periods 5 and 7.5 sec. and exceeded 2m from 3.5 to 9 sec of sloshing period and that severely damaged tanks had the highest Wh at each period in general.
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Haruki NISHI, Minoru YAMADA, Shinsaku ZAMA, Ken HATAYAMA, Yoshihiro HI ...
Article type: Article
Session ID: 112
Published: September 04, 2004
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There was a fire at a crude oil tank in Tomakomai City after the 2003 Tokachroki Earthquake. A nearby naphtha tank caught fire two days after the earthquake and the fire became an "open top fire". Moreover, floating roofs sank beneath the oil in seven tanks after the earthquake. There also occurred a considerable number of oil leakage accident in many oil storage tanks in Tomakomai City. The authors have investigated the damage to the tanks. The crude oil tank that caught a ring fire was a floating roof tank and had a capacity of 30,000kl. The authors have analyzed the effect of liquid sloshing of oil on the fire by conducting time history response analysis with finite element method using strong ground motion records.
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Yoshihiro Narita
Article type: Article
Session ID: 113
Published: September 04, 2004
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A survey was made to cover the recent development in the finite element analysis of shell structures. It was found that the considerable efforts have been made in the past five years to create new types of finite elements for analyzing various mechanical behaviors of shell structures, particularly of composite shell structures.
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Atsushi TAKEHARA, Takao MORI, Toshihiko SAYAMA, Takeshi TAKAYANAGI
Article type: Article
Session ID: 201
Published: September 04, 2004
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This paper describes phase growth of Sn-3.OAg-0.5Cu solder joints by a mechanical fatigue test. A lap joint type shear specimen was used to evaluate the influence of temperature and strain on the phase growth of solder joints. The fatigue test was carried out under constant temperature condition. Nonperiodically the specimen was taken out from the chamber and the micro structure of the solder joint was observed by the scanning electron microscope (SEM). Consequently, in Ag_3Sn phase growth proceeds so that the average phase size to the 4th power is proportional to the number of cycles, and is mainly induced by strain rather than thermal equilibrium.
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Jae-Chul JIN, Qiang YU, Hirokazu ABE, Masaki SHIRATORI
Article type: Article
Session ID: 202
Published: September 04, 2004
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In recent years, package downsizing has become one of biggest trends in packaging technologies because of miniaturization and the high integration of electronic devices. As a result, the reliability of fatigue life has been prioritized as an important concern. But, the reliability of thermal fatigue life in the solder joint may be lowered by the change of design factors such as the dimensions, shapes, and material properties of package systems. So, the influence of these design factors for the fatigue life should be examined in order to improve the reliability. In this study, the evaluation of influence of various design factors on the reliability of BGA (Ball Grid Array) solder joints was carried out, and got each influence. And, the mechanism influenced in the fatigue life was clarified. With the results, design engineers can rate each factor's effect on reliability and assess the reliability of their design beginning at the concept design stage. Consequently, it will be possible to avoid almost all reliability problems from the beginning. Also, by rating the factors, the design period can be shortened.
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Kimimasa MURAYAMA, Takashi NAKANISHI, Kazuhiro IGARASHI, Qiang YU, Mas ...
Article type: Article
Session ID: 203
Published: September 04, 2004
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In recent years many electric equipments have come to be used for cars. Solder joints in electric device utilizing car are exposed to harder environment and required higher reliability than that in electric household appliances. Because of this reason, thermal fatigue reliability of solder joints has become one of the most important issues in car electronics. Generally thermal fatigue reliability is estimated by thermal cycle examination, but it needs long time. Estimation by FEM enables it to improve reliability and to reduce time. Analysis of solder life generally can predict only initial crack. But it is important to predict crack propagation and solder joints breakdown, considering that a function of solder joints is electric connection. In this study, the authors proposed a method to predict break down life by analytical approach.
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Hisashi TANIE
Article type: Article
Session ID: 204
Published: September 04, 2004
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We investigated the mechanism of crack propagation in micro-solder joints with a semiconductor structure and developed a new crack propagation model. In micro-solder joints, solder crack might propagate not only at the interface itself but also near the solder and land interfaces. Conventional crack propagation models based on fracture mechanics, however, cannot explain this phenomenon. In our model, the fatigue life of solder was evaluated based on accumulative damage during crack propagation, and a crack path was automatically calculated. Using this model, we analyzed the crack path of a ball grid array (BGA) structure and determined that this model can reproduce the above phenomenon.
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Hideo Koguchi, Wisessint Attaporn, Kazuto Nishida
Article type: Article
Session ID: 205
Published: September 04, 2004
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An anisotropic conductive film (ACF) is used for the flip chip assembly as one type of underfill. Our analysis is focused on elastic recovery arid stress distribution along the interfaces in particle-pads and underfillpads due to a thermal loading. The process for ACF interconnection is simulated by FEM. The viscoelastic properties are used in underfill. To analyze the failures by thermal shock during cool down process, three patterns of cool down rate are used. The results of stress distribution in each patterns will be presented.
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Toru IKEDA, Won-Keun KIM, Noriyuki MIYAZAKI
Article type: Article
Session ID: 206
Published: September 04, 2004
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Anisotropic Conductive Adhesive Film (ACF) has been used for electronic assemblies such as the connection between a Liquid Crystal Display (LCD) panel and a flexible print circuit board (FPC). Recently, the ACF is expected to be a key technology for flip chip packaging and SiP (system in packaging). The goal of our work is to provide an optimum design scheme to achieve the best combination of electrical performance and mechanical reliability for electronic packages using the ACF. The stress intensity factors of an interface crack between jointed dissimilar materials were, utilized for the evaluation of the delamination occurred in a flip chip connected by the ACF under moisture/reflow sensitivity tests.
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Hironori TOHMYOH, Tsuyoshi AKAOGI, Masumi SAKA
Article type: Article
Session ID: 207
Published: September 04, 2004
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Dry-contact ultrasonic technique, which realizes the ultrasonic imaging without getting a sample wet, is a useful method for the inspection of electronic packages. In this study, we transmit high frequency ultrasound into the acrylic resin targets via four kinds of elastomer membranes with stability, and high durability, and select a membrane for cyclic ultrasonic imaging under a dry-contact condition. For recording high quality acoustic images, the membrane must satisfy the low ultrasonic attenuation and high acoustic coupling at the membrane/sample interface. Finally, we perform the cyclic ultrasonic imaging of an electronic package via the selected membrane, and repeatedly visualize the delamination in the package.
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Tomio HAYASHI, Hidehiko SOGO, Kenichi INOKUCHI, Kazuya UENO
Article type: Article
Session ID: 208
Published: September 04, 2004
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With developing high performance of personal computer, EBSP (Electron Bask Scatter diffraction Pattern) technique was focused on the evaluation for the microjoining area in semiconductor package. The main purpose of this study was to clarify the crystallographic texture of lead free plating in order to investigate the growth mechanism of Sn whisker. In this study, EBSP technique was adopted to the gull wing type of outer lead with Sn whisker. In the result, it was found that Sn whisker was growing at triple junction of grains. And it was considered that misorientation of triple junction of grains were caused internal stress in Sn plating.
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Hideo Koguchi, Mirai Ishida, Kazuto Nishida
Article type: Article
Session ID: 209
Published: September 04, 2004
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In the present paper, a deformation induced in a new bonding technology of Chip Size Package (CSP) using resin encapsulation sheets is examined numerically and experimentally. Deflections after cooling from a bonding temperature are measured experimentally for various kinds of substrate and the thickness of an integrated circuit using a laser beam. In particular, a simple theory on the basis of a multilayered plate theory considering a viscoelastic property in the substrate and encapsulation are presented, arid the thermo-viscoelastic analysis for the deflection of CSP is performed. We could show that the simple formula for multilayered plates based on the thermo-viscoelastic theory can estimate fairly well the deflection of CSP in experiment.
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Qiang YU, Keiji WATANABE, Toshihiro TSURUSAWA, Tsuyoki SHIBATA, Masaki ...
Article type: Article
Session ID: 210
Published: September 04, 2004
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The purposes of this study are to clarify the dynamic behavior of BGA or CSP packaging subjected to an impact loading, and to establish a simple analytical method of impact reliability assessment for spider joints. In this study, it is found that opening mode of jig affects bad when the repetitive drop test was carried out. So to reduce effect of opening mode, we investigate in view-of natural frequency. Furthermore, considering drop impact problem is very difficult problem. As a evaluation method, we proposed restitution coefficient as evaluation parameter, and examined effect of restitution coefficient using FEM analysis.
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Shigeru OHKI, Hikari SANO, Masanori MINAMIO, Haruto NAGATA
Article type: Article
Session ID: 211
Published: September 04, 2004
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The new lead-frame-type SiP which has a merit of heat radiation, heat resistance and low cost manufacturing has been developed. By the best use of CAE, we could simulate the thermoset moid flow movement and stress analysis. To develop the very thin package, we realized to prevent the incomplete molding and minimize the wire sweep. We considered the reliability of the thermoset mold injection using the stress analysis at designing stage. We confirmed that the result of simulation corresponded to the result of experiment.
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Kenya KAWANO, Satoru KONISHI, Tsuneo ENDO, Mamoru IIZUKA, Hideo MIURA
Article type: Article
Session ID: 212
Published: September 04, 2004
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A method for evaluating fatigue life of the bonding wires in semiconductor packages under a temperature cycling test was studied analytically using a finite element method based on design of experiments. The sensitivity analysis of the maximum strain occurs in a bonding wire was carried out to make clear the effect of the loop-shape of the wire on the strain. It was found that we can evaluate the fatigue life of a bonding wire under various conditions of a temperature cycling test at the early stage of design by using both the Chebyshev function of a loop, shape factor and the Manson-Coffin fatigue life curve. It was also found that highly reliable loop shape of the wire can be designed by minimizing the strain using design of experiments.
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Yasuyuki YOKONO, Tadashi KUROIWA, Ryo FURUKAWA, Minoru MUKAI
Article type: Article
Session ID: 213
Published: September 04, 2004
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The power unit design was completed utilizing the multi objective optimization based on a neighborhood cultivation genetic algorithm. The pressure drop, thermal resistance, strain, fin height and flow velocity were examined simultaneously as the design objectives. It was able to visualize these correlations and trade-off relations. The design proposal could be obtained from the pareto solutions which were connected with the objective functions. This approach could visualize a design process and improve the quality and speed of a design, compared with the conventional series design which determines each evaluation functions in order.
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Hiroki MAMIYA, Koji ISHIKAWA, Qiang YU
Article type: Article
Session ID: 214
Published: September 04, 2004
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We report on the development of a new micro-electro-mechanical systems (MEMS) optimal design method called Computer Aided System Evaluation (CASE), which supports the total system evaluation of MEMS devices before the design stage. In our design method, we can clarify and simplify the relation between design parameters and the system characteristics using a CASE weighted orthogonal array. In the CASE array, the sensitivity of each design factor for the system performance shows numerically how the design parameter influences the system characteristics. The existent trade-offs between design parameters can be minimized by both modifying the design concept and adjusting the sensitivities. Therefore MEMS designers are able to optimize the total system based on the information from the CASE array. To conduct the informative optimal design method at the beginning of development leads the reduction of the total MEMS design time and cost.
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Kazuyuki Nakayama, Masaru Ishizuka, Shinji Nakagawa
Article type: Article
Session ID: 215
Published: September 04, 2004
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This paper presents the experimental results regarding the thermal performance of a PBGA package model mounted on a printed circuit board in a thin compact casing. The casing exit was linked with an exhaust duct that has an orifice plate for flow rate measurement and an exhaust fan. The effect of the relative position of the PBGA package and a cooling air inlet on the thermal performance was examined. It is confirmed that air flow through a narrow inlet diffuse slightly and that increasing the streamwise distance between the package and the inlet has a limited effect.
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Yoji KITAMURA, Masaru ISHIZUKA, Shinji NAKAGAWA
Article type: Article
Session ID: 216
Published: September 04, 2004
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In this paper are presented the results of an experimental and numerical study on the flow resistance values by the obstacles in a natural air-cooled electronic equipment casing derived by using the design formula. Experiments have been carried out using a ventilated electronic equipment-casing model, with a wire-heater inside and inlet and outlet vents on the walls of the casing. In order to evaluate the natural convective air-cooling capability, the chimney height that is defined as the distance between the main heat dissipated component and outlet vent has been varied. Arid, volume porosity coefficient in the casing was also varied from 46.4% to 100.0% with flow obstacles being varied when power dissipation was 30W. It is found that the average temperature rise and the flow resistance coefficient in the casing didn't increase until volume porosity coefficient was about 50%, but maximum and wall temperature rise were increase almost linearly.
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Satoru GIMA, Takehiro NOSOKO, Xing ZHANG, Motoo FUJII
Article type: Article
Session ID: 217
Published: September 04, 2004
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This paper reports on measurements of conjugate heat transfer from a model package placed on a PCB located in a rectangular duct cooled by air. The model package used by the present experiment is isothermal model, which is composed of two copper plates sandwiching a foil heater and a heat flux sensor. The effects of the thermal conductivity of PCB and the other small heat sources around the model package on the conjugate heat transfer characteristics were studied experimentally. Using the concept of effective heat transfer area, a unique non-dimensional correlation is proposed, which can predict the maximum temperature for various thermal conductivity of PCB. The correlation is also applicable for two small heat sources around the package.
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Nobuyuki ISOSHIMA, Itsurou SAWADA, Masatoshi WATANABE, Hideharu SAITOU
Article type: Article
Session ID: 218
Published: September 04, 2004
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The numerical simulation code with a finite difference method for unsteady three-dimensional thermal flows was developed in a Cartesian grid system. The code enabled us to predict flow fields around complicated geometries in a short pre-processing time. First, the present code predicted flow fields around a flat plate which was heated at a constant temperature, and it was confirmed that the results agreed with those obtained by analytical solutions in 20%. Finally the code was applied to the prediction of flow field of a LCD Projector which had highly complicated internal structures such as lamp, LCD panels, and electric parts etc.
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Katsuhiro KOIZUMI, Masaru ISHIZUKA
Article type: Article
Session ID: 219
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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High-frequency inductors are one of the most significant loss contributors in a switch mode power supply (SMPSX However, in making a thermal flow simulation model, it is not realistic to model the detailed structure of a high-frequency inductor due to the high calculation cost. Therefore, to find a compact modeling method for an inductor component in SMPS, we investigated the effect of proximity losses that occurs near the air gap, and the effect of anisotropie effective thermal conductivity in an inductor winding on the winding surface temperature.
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Toshio TOMIMURA
Article type: Article
Session ID: 220
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In the electronic equipment like personal computers with high heat fluxes for instance, the thermal contact resistance (TCR) plays an important role in heat removal process. In such equipment, an interstitial material is often introduced between the heat sink and the heat source to reduce TCR. In this study, in succession from the previous, studies, the effect of grease layer on TCR between contacting surfaces with waviness has been investigated experimentally. As a result, it has been clarified that the thickness of the grease layer is about 24μm, and by applying such thin layer at the interface, fairly good reduction effect of TCC is obtained.
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Yoshinari IKEDA, Katsuhiko YOSHIHARA, Yuji IIZUKA, Mitsuo YAMASHITA
Article type: Article
Session ID: 221
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper reports about the new interconnection technology for Power devices. Al wire bonding(WB) have been a standard interconnection at Power devices. Al WB is an effective, interconnection to supply currents to the power chip, but is not effective to remove power losses from the power chip surface. To remove power losses from the power chip surface, we apply Lead Frame(L/F) interconnection to the power chip with electroless Ni/Au plating electrode. We carried out finite element method(FEM) analysis about heat transfer, made L/F prototypes and evaluated them. The FEM analysis and experimental results show that L/F interconnections make lower junction temperature than Al WB interconnections.
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Masao Fujii, Yu Seshimo
Article type: Article
Session ID: 222
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Improvement on mounting thermal resistance in electronic cooling is studied using a newly developed flexible thermal contactor (FTC) as an interstitial material. The FTC consists of two materials with highly thermal conductivity and elastic like a spring. The FTC improves the mounting thermal resistance to obtain uniform temperature distribution in a printed circuit board with many electronic components. The mounting thermal resistance of the FTC is analyzed by using a thermal network.
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Tomonori KANEKO, Ichiro HAGIWARA, Xin TAO
Article type: Article
Session ID: 223
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Considering pedestrain and/or low speed Vehicle collision problems it is effective to get deformation as much as possible along with comparatively small load. These problems are supposed to be axis crash problems, so it is important how to make accordion-like folded patterns. Therefore in this research, we use the idea of the Origami Model. We find several kinds of structure, which can be folded completely. Then we examine the characteristic of structure, which is possible to be certified with finite element method simulation.
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Xin TAO, Zhuoqi WU, Ichiro HAGIWARA
Article type: Article
Session ID: 224
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Recently origami technique is prepared to be applied to many industrial products. For example, a new kind of beverage container made by origami structure has been introduced. Previous research has presented that it can be easily crashed after usage. However, its performance especially external appearance does not meet industrial requirements. Therefore, in this research, starting from the view of industrial design, the structure of beverage container is modified by the subdivision technology. Crashworthiness of modified origami structure is studied by FEM. Analysis results indicate that modified origami structure is suitable for beverage container.
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Atsushi SAITO, Taketoshi NOJIMA
Article type: Article
Session ID: 225
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The present report describes a designing concept for foldable/deployable functional structures. We devised the foldable models based on Fulleren(C_<60>) structures and proposed the new type of foldable dome-structure models. We compared some models in the view of their foldabilities and deployabolities and devised the suitable models.
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Taketoshi NOJIMA, Atsushi SAITO
Article type: Article
Session ID: 226
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The aim of the present work is to develop various kinds of functional structures consisting of golden spirals/golden mean spirals which are often found in organic structures. The possibilities of designing using such spirals are discussed from a geometrical point of view.
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Ryo TSUCHIYA, Itsuro KAJIWARA
Article type: Article
Session ID: 227
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper proposes a multidisciplinary design approach of piezoelectric actuator and control system for smart structures that have a characteristics variation. The length of a beam-type smart structure changes and so the characteristics of the system is varied. The system is composed of piezoelectric actuator array and scheduled controller. The control system is designed according to the H_2 specification with a reduced-order modal model. An adaptive control is conducted by scheduling the actuators and the controllers to keep the stability and performance against the characteristics variation of the system. The design problem for improving the H_2 performance is defined, and then the piezoelectric array and the scheduled control system are simultaneously optimized by the presented approach, resulting in an enhanced performance for the vibration control.
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Hideki NAGAI, Ryutaro OISHI, Ya XU, Hitoshi YOSHIDA, Norio AMI
Article type: Article
Session ID: 228
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes smart structure composed of Ti-Ni shape memory alloys (SMA) and elastic materials. SMA is one of the effective materials which posses actuator function for start structure. However, in the conventional application of SMA, its shape change is non-reversible. Under certain conditions, SMA can show two-way shape memory effect. But conventional two-way SMA is not used for smart structure because stability of the effect and strength of generated force is not sufficient. Composing SMA with elastic materials, the structures can response reversibly depending on temperature. In this paper, application of ring-shape type smart structure is mentioned. Analytical models of reversible shape change and generated forces are led and the validity of the models is shown by comparison with experimental results. Then a new protective garment system, with which the technology is put in practical use, is introduced.
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Makoto YOSHIDA, Jinhao QIU
Article type: Article
Session ID: 229
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes a study of active noise isolation of an acoustic power mode. Generally, the simple suppression of the structure vibration does hot necessarily result in good reduction of radiated noise, but acoustic power mode is an effective factor which connects the vibration and the radiated sound. By calculating power transfer matrix, the influence which each mode has on acoustic power is found and by using PZT as mode sensor, it will be possible to control the acoustic power modes with adaptive algorithm such as LMS.
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Shunsuke EHARA, Masaki KITAGO, Ichiro HAGIWARA
Article type: Article
Session ID: 230
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In the case of transfer of data with different CAD or CAE, by the difference in accuracy or a curved surface, inconsistency occurs in a model and the compatible fault of the joined field exfoliating happens. In this paper, from the CAD data containing these imperfection, a surface point is extracted and the surface is reconstructed by the single formula with an implicit function. 1 The crack of a local field can be complemented with reconstructing with an implicit function, and it becomes possible to re-define a solid model. And we build FEM model of using this implicit surface.
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Irina Semenova, Ichiro HAGIWARA
Article type: Article
Session ID: 231
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this paper, we present a novel technique to improve quality of triangular surface meshes while maintaining all essential surface characteristics. In contrast to previous methods we do not constrain node movement to the underlying discrete surface. Instead our approach allows keeping resultant mesh very close to the smooth surface approximated by the original mesh. Proposed method is explicit, that is we do not need any parameterization of the original mesh. All operations are performed directly on the surface. As a result our technique is robust and runs at interactive speeds.
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Ichiro NISHIGAKI, Hiroaki DATE, Satoshi KANAI
Article type: Article
Session ID: 232
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We have developed an appearance-design-CAD-coupled simulation framework that will enable engineers to perform analysis simulations during the appearance design process. This is not only a prototype process, but also the most innovative product design process to date. We applied multi-resolution representation technology to an automatic mesh generation system, in order to obtain low-resolution analysis meshes from high-resolution appearance design meshes. Because engineers are able to design appearance and function all at once, we can eliminate redesigns caused by design defects in the original function design process.
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