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Yoshio AOKI, Yasuyoshi IWASE, Goichi BEN
Article type: Article
Pages
195-196
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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This paper presents a vibration suppression test of composite material, in which shape memory alloy perpendicularly embedded into CFRP or GFRP laminates. First, we show how to fabricate two kinds of hybrid composite. Next, we examined that the vibration of SMA/GFRP and SMA/CFRP hybrid composite could be suppressed by heating/cooling the embedded SMA fiber were heated by direct electric current, and cooled by a natural convention. The vibration suppression test demonstrates an effective possibility of SMA fivers in the hybrid composite structural element in the process of controlling the vibration. Last we organized sensing system with SMA fiver Resistance change.
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Yun LUO, Kumiko YAKUWA, Toshiyuki TAKAGI
Article type: Article
Pages
197-198
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Thermoelectrically driven manipulators comprised of shape memory alloys (SMAs) and Peltier elements have been proposed. SMAs exhibit a large recovery force and a recovery strain due to phase transformation. The main advantages of SMA manipulators are lightweight, simple and compact designs. Recovery force and deformation characteristics of the manipulators have been investigated. Peltier modules as thermoelectric devices can keep any temperature within transformation temperatures of SMAs, controlling heat transfer by applying an electrical current. Therefore these are easy to control work output and make it possible to shorten response times. This paper describes the response properties.
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Hiroshi ASANUMA, Takeshi MOCHIZUKI
Article type: Article
Pages
199-200
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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This paper describes fabrication of an active composite working at high temperatures. In this study, the concept of aluminum matrix active composite was applied to nickel matrix composite. In this case, SiC/Ni layer was laminated on unreinforced nickel plate with aluminum insert. Fabrication condition of this material was examined and an appropriate condition, that is, hot pressing condition of 993K, 27MPa and 4.8ks in a low vacuum of 1×(10)^2 Pa using 0.1mm thick insert was obtained. The curvature of this composite increased with increasing temperature up to higher than 1200K and the maximum working temperature without hysteresis was found to be about 670K.
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Takashi GOTO, Osamu HAGA, Hiroshi ASANUMA
Article type: Article
Pages
201-202
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The Thermally induced shapes of the A1/CFRP laminated materials can be controlled by Joule heating and they can be predicted theoretically by the Rayleigh-Ritz method. When the width and length of a laminate is small, its cured shape in the room temperature becomes only a saddle. But, if the size of the plate is greater than a critical dimension, the room temperature shape of it becomes either a saddle or a cylindrical shape. Results of the stability analysis of the predicted shape showed that it takes a cylindrical shape. When temperature changes from the room temperature and more than the temperature the shape becomes only a saddle. It was also shown by the stability analysis that the shape of the laminate changes from the cylindrical shape to the saddle shape. The above things were confirmed by many experiments.
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Jinhao QIU, Junji TANI, Nishina KAMIMURA, Masakazu HARAGUCHI
Article type: Article
Pages
203-204
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Multifunctional smart boards with embedded piezoelectric sensors and actuators for health monitoring, impact identification, and vibration and noise control are under development at Tohoku University. In this paper the health monitoring function of the smart board to identify the position of an attached mass is introduced. The localization used the variation of peak frequency in the electric impedance curve of the imbedded piezoelectric elements and a radial basis neural network. The peaks in the electric impedance curve of the PZT elements correspond to the natural frequency of the in-plane vibration mode of the board and their frequency changes due to the attachment of mass. The effectiveness of this method was verified in the experiment.
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Kazuro KAGEYAMA, Isamu OHSAWA, Makoto KANAI, Yukiya TSUCHIDA, Keiich N ...
Article type: Article
Pages
205-206
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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A new fiber-optic vibration sensor has been developed and applied to structural health monitoring. The sensor is based on a new finding that frequency of light wave transmitted through an bended optical fiber is shifted by vibration at the bended region. A very high sensitivity has been achieved in the extremely wide frequency band. The performance of the sensor is examined experimentally. The sensor is applied to detection of AE signals and elastic wave propagation in the composite material. The durable, low-cost and high-sensitive sensor can show a new scope to structural health monitoring in the very variety of applications.
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Akira TODOROKI, Yusuke TAKEUCHI, Tsuneya SUGIYA
Article type: Article
Pages
207-208
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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When a large-scale disaster occurs, much destruction of large civil structures happens, for example waterworks, sewerage pipe, gas pipeline, tunnel, and bridge. These structures must be repaired immediately. But it is difficult to get information of locations of the destruction exactly, because traffic is disrupted in the time of a disaster. Also, when a small-scale disaster occurs, it is require much time and money to get information of the destruction and to ensure these safeties, because these destructions happen in a broad range. So it is requested to develop the simple monitoring system of destruction and transformation of civil structure and lifeline. This study develop simple composite fracture sensor and Internet connect terminal (i-Station) that connected with Internet cable, and propose the remote health monitoring system. Making concrete work, firstly we develop composite sensor and Internet connect terminal for health monitoring of sewerage pipe build reinforced concrete and that destruction progresses gradually, the validity of the integration system that used these systems is proved.
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Akira TODOROKI, Shintaro MIYATANI, Yoshinobu SHIMAMURA
Article type: Article
Pages
209-210
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Strain monitoring of tires of automobiles in-service is quite effective to improve reliability of tires and design tools. In the previous study, authors have proposed a new wireless strain monitoring method that adopts a tire itself as a sensor with an oscillator circuit. In the present study, a new passive strain measurement system utilize electric capacitance change of steel wire reinforced tires is proposed and experimentally investigated. The passive wireless strain monitoring method makes use of the specimen cut from the tire as a condenser of a passive filter circuit. Deformation of the tire brings capacitance change of the tire comprises steel wire and rubber; the change of the capacitance makes the change of filtering frequency of radio wave. Measurement of the frequency of radio wave passed through the filter circuit enables us to measure the strain of the tire wirelessly. A rectangular specimen cut from a commercially available tire is adopted as a specimen. Tension test is performed and the change of filtering capacity is measured during the test. As a result, the method is experimentally proved to be effective for the passive wireless strain monitoring of tires.
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Akira TODOROKI, Miho TANAKA, Yoshinobu SHIMAMURA
Article type: Article
Pages
211-212
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Since a delamination of laminated composites is usually invisible or difficult to detect visually. The delamination causes low reliability for primary structures. To improve the low reliability, automatic systems for delamination identifications in-service are desired. The present study employs and electric resistance change method for detections of the delaminations. Since the method adopts reinforcement carbon fiber itself as sensors for the delamination detections, this method doesn't cause reduction of static strength or fatigue strength, and the method is applicable to existing structures. Authors have revealed that the electric resistance change method with response surfaces is very effective experimentally and analytically. For the estimations of delamination locations, this method reveals excellent high performance of estimations of delamination location. Multiple electrodes are mounted on the specimen surface in this method. The spaces between the electrodes mounted on the specimen surface cause the difference for the performance of estimations of delamination. We change the spaces between the electrodes on the specimen surface and investigated the influence of the spaces for the delamination monitoring.
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Atsushi Iwasaki, Akira TODOROKI, Tsuneya Sugiya
Article type: Article
Pages
213-214
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The present paper proposes a new diagnostic tool for the structural health monitoring that employs a statistical diagnosis of self-learning method using a system identification and statistical similarity test of the identified systems using F-test. Structural health monitoring is a noticeable technology for advanced composite structures and civil structures. Most of the structural health monitoring systems adopt parametric method based on modeling or non-parametric method such as artificial neural networks. The former method required modeling of each structures and latter method requires data for the training. And these modeling and data for the training demands much costs. The new statistic diagnosis method does not require the complicated modeling and a learning data of damaged structure for the artificial neural networks. The present study deals monitoring of delamination of composite beam using change of strain judged by the statistical tools such as Response Surface and F-Statistic. Response surfaces among the measured strain data of surface of composite beam are produced at intact state and monitoring state, and the difference of the each response surfaces are statistically tested using F-test. As a result, the new method successfully diagnoses the damage without using modeling and a learning data of damaged structure.
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Yasuyuki MITSUI, Osamu KUWAZURU, Nobuhiro YOSHIKAWA
Article type: Article
Pages
215-216
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The conventional ab-initio calculation is performed by the spectral method based on the plane waves, and needs extremely high computational cost to realize sufficiently accurate analysis. Presented here is a new formulation of the quantum mechanical analysis based on the finite element method. The presented method can minimize the degrees of freedom for calculation, and does not need the Fourier transformation. The computational cost, therefore, seems to be drastically reduced. For the sake of mathematical simplicity, the problem of an electron of the ground state or the time evolution in the simple Coulomb potential are employed in the proposed formulation. The variational forms of the time-dependent and time-independent Schrodinger equations are individually derived by means of the weighted residual method. The finite element is formulated in line with the descritization of the variational forms by conventional shape functions.
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Tokuteru UESUGI, Masanori KOHYAMA, MASAHIDE Kohzu, Kenji HIGASHI
Article type: Article
Pages
217-218
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The lightweight and high specific strength magnesium alloys are important as structural materials. However, magnesium and magnesium alloys have low plastic formability. It is important to understand the deformation mechanism to improve their plasticity. In the behaviors of slip deformation and dislocation motions, the critical and effective parameter is the generalized stacking fault (GSF) energy. In this work, the GSF energies on basal, prismatic and second-order pyramidal plane in magnesium are calculated by ab initio pseudopotential method. Then the Peierls stresses are obtained from calculated GSF energies within the framework of a Peierls-Nabarro model. The magnitude of the Peierls stress is in good agreement with experimental measurement.
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Kengo Tsuchiya, Tokuteru Uesugi, Masanori Kohyama, Masahide Kohzu, Ken ...
Article type: Article
Pages
219-220
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Aluminum is a typical example of the ductile metal and it is significant that we researched the sliding mechanism of grain boundaries. In this study, the atomic structure and electronic state of the Σ=5 (001) twist grain boundary are analyzed with ab-initio molecular dynamics simulation. Our purpose is to clarify the process of Al sliding deformation in consideration of the electronic state. The grain boundary energy and the deformation energy of the grain boundary where there are no dislocations. As the result we discussed the fact that the strength of grain boundary sliding depends on the sliding directions. Moreover, we thought about the grain boundary dislocations.
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Yoshitaka UMENO, Takayuki KITAMURA
Article type: Article
Pages
221-222
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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It is of great importance to elucidate atomic structure and bonding system at a contact of different materials in terms of understanding various characteristic properties emerged by the contact. In this study, ab initio molecular dynamics simulation on precipitation of Al atoms onto Si surface is conducted to investigate the atomic and electronic structure of the contact of Si/Ai. At first, Al atoms are settled above a ditch between dimer rows of the Si surface and are arranged in a line. After the ditch is filled with the Al atoms, Al atoms are adhered near the line and they construct bonds with each other and with Si atoms in the dimers as well. Consequently, a dense Al layer is formed on the Si surface.
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Akihiro KUSHIMA, Yoshitaka UMENO, Takayuki KITAMURA
Article type: Article
Pages
223-224
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The tight-binding (TB) method, which is based on the semi-empirical band calculation of materials, has been widely applied to atomic simulations. However, the validity of the method under high strain condition has not been clarified. In this study, in order to verify the applicability of the TB potential for silicon to high shear strain condition, the simulation results are compared with those by the ab initio calculation. The non-orthogonal TB potential, which takes the overlap interaction between atomic orbitals into account, shows good agreement with the ab initio calculation, while results obtained by the orthogonal TB potential, which ignores the ovelap interaction, and the empirical Tersoff potential are much different from that.
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Yutaka SUDOH, Mitsuo NOTOMI, Hisao HASEGAWA, Haruo SIMOSAKA, Noburo EH ...
Article type: Article
Pages
225-226
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The purpose of this research is that the variations of potential energy of Ti Ni shape memory alloy (SMA) are obtained during slip and compared with the experimental results. This energy is calculated using by Modified Embedded Atom Method (MEAM) as a semi-empirical potential energy calculation. First, the potential energy of the FCC structure of Ni is calculated during the several kinds of slip system, {111}<101>, {111}<112> and {110}<110>. All of the potential energy increase with the slip from the stable structure and attain the peak, i.e. the maximum energy. The peak energy of {111}<101> is lowest those of the other slip systems. This indicates that a slip occurs along <101> direction within <111> plane and this is the real slip system of Fcc metal. Second, the potential energy of the B2 structure of Ti Ni SMA is calculated during slipping an atom along <111> direction on {110} plane and <001> direction on {110} plane. The peak of {110}<111> which is the real slip system of BCC is lower than {110}<001>
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Tetsuya KUGIMIYA, Takashi KAWAKAMI, Shigenobu OGATA, Yoji SHIBUTANI
Article type: Article
Pages
227-228
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Shear deformation of a single crystal silicon is analyzed using the empirical Tersoff potential Tight-binding (TB) method and ab-initio calculation. As a result of using the Tersoff potential and TB method with the Wang's TB potential, the energy changes of a twining mode are different from the ab-initio results. It is found that these potentials can not represent the reasonable stress state under the highly shearing strain. TB calculations shows that the bond breaking process at the relaxation of atomic configurations is obtained, which is in good agreement with the ab-initio results.
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Kinichi JINDO, Madhu MENON, Shuji OBATA
Article type: Article
Pages
229-230
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Tadao FUKUTA, Yasuhiro AKAHOSHI, Shoji HARADA
Article type: Article
Pages
231-232
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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It is well known that nuclear pressure vessel steel shows embrittlement under thermal aging and strong neutron irradiation. To examine this attention has been paid to copper-rich precipitates how they work to embrittle reactor pressure vessel steels. Our final goal is to evaluate such embrittlement from microscopic viewpoint based on atomistic simulation. In this study, we simulate interaction between motion of an edge dislocation and copper precipitates using Molecular Dynamics (MD) method with a periodic boundary condition, where uniform shear strain is applied to the boundaries parallel to the slip plane (1 1 2) in the system. As the result, it is clear that a precipitate has an effect on motion of edge dislocation. We was able to confirm a remarkable change of energy and increase of shear stress in a precipitate neighborhood. Even if we consider that it is an effect in a limited part, we think that interaction between dislocartion and precipitate give an effect to embrittlement.
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Hideo KOGUCHI, Akira SHIMIZU
Article type: Article
Pages
233-234
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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In this study, the action of each atom is simulated using the molecular dynamic method. The equation of motion for atoms in a three-dimensional space is solved using Velocity Verlet algorithm, and the motion of atoms is traced numerically. When strain is applied to material, and a relationship between the applied strain and surface stress is investigated. Surface stresses relates with a reconstruction of the surface atoms.
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Shotaro HARA, Satoshi IZUMI, Shinsuke SAKAI
Article type: Article
Pages
235-236
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Surface energy, surface stress and surface elastic constants are key parameter for predicting of the intrinsic stress of thin film. We have evaluated these surface properties for Si(100)1×1 surface and amorphous silicon surface by using molecular dynamics simulation (MD). The model predicts that the surface elastic constants are independent of film thickness (>1nm). Finally, we have investigated on how to apply the parameters calculated at the atomic level to continuum level.
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Haruo NAMAKURA, Tetsuji SHIMOMURA, Sonoko MAEDA
Article type: Article
Pages
237-238
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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A molecular dynamics (MD) approach was applied to delayed fracture initiation from a free surface of pure Cu under corrosive environment to investigate brittle fracture mechanism. It was found that a thin brittle oxide film has an important role on initiation of brittle crack initiation behavior.
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Takeshi SUNAGA, Katsuya TAGAMAI, Masaki YAGI, Tomoyasu AIHARA
Article type: Article
Pages
239-240
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Hydrostatic pressure effect on liquid-glass transition and kinetics for crystallization of supercooled liquid or amorphous solid of Lennard-Jones single component system were examined by molecular dynamics simulation. Temperature dependence of diffusion coefficient, specific heat at constant pressure and thermal expansion coefficient of Lennard-Jones liquid were analyzed.
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Wataru NAKAYAMA
Article type: Article
Pages
241-242
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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This paper describes a JSME project that is aimed at implementing a methodology called the Build-up approach (BUA). The BUA is designed to expedite thermal design of electronic equipment through hierarchical organisation of the design work. In the knowledge development level, the computational fluid dynamics (CFD) simulation is performed on a set of template designs. From the solution body a fast-to-use design code will be developed for use in the actual design phase. Expected benefits of and the key steps involved in the BUA are explained.
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Daisuke YOSHIDA, Shigefumi NISHIO
Article type: Article
Pages
243-244
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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COSMOS Heat Pipe, which is a kind of oscillatory-controlled heat transport tubes, has strongly curved capillaries inside. The driving power of fluids in tube with strong curve was examined experimentally to estimate the operation coefficient (defined by a ratio of heat transport rate and added driving power) of COSMOS Heat Pipe. The result shows that the power to drive oscillatory flow in strongly curved capillary can be about twice larger than that of straight one under some conditions. Heat transport experiment was also carried out, and it was shown that the estimated operation condition of COSMOS Heat Pipe is fairly high.
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Yoji KITAMURA, Masaru ISHIZUKA, Guoyi PENG
Article type: Article
Pages
245-246
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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In this paper are presented the results of an experimental study on the chimney effect on natural convection induced airflow for cooling electronic equipment. In order to enhance the natural convective air-cooling capability, the chimney effect is increased by placing the casing wall inclined. Experiments have been carried out using a ventilated thin electronic equipment-casing model with a plate heater and PCB heater inside and inlet and outlet vents on the walls of the casing. In our study, the angle of inclination, the amount of heat of dissipation was varied with casing which has no front and back wall.
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Katsuhiro KOIZUMI, Kuniaki NAGAHARA, Masaru ISHIZUKA
Article type: Article
Pages
247-248
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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In developing a new switching power supplies, detail thermal assessment of the complete system was very time consuming and expansive process. Therefore it was very much desirable to use some engineering tool which could drastically reduce both time and cost required for the development process. In the present work, a thermo-fluid simulation technique is used as an engineering tool in the thermal designing of switching power supplies. The modeling and development of analytical condition for the individual components necessary for the simulation are studied and the results are presented. The result lead to the understanding that the proposed simulation technique is very effective in the designing of arrangements of the components mounted in the printed circuit board.
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Qiang YU, Hironobu KIKUCHI, Keiji WATANABE, Masaki SHIRATORI
Article type: Article
Pages
249-250
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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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 solder joints. In this study, the repetitive drop test was carried out to observe the crack propagating processes. From the results of the repetitive drop test, it was found that the dynamic fatigue crack concentrates at the interface between the copper pad and solder bulk. And a large plastic deformation domain was not found around the crack tip. So the authors evaluated the crack growth based upon the elastic fracture mechanics theory. As an analytical method, 3D analytical models with the crack tip were used for the elastic FEA to calculate the stress intensity factor K_I. And the authors showed a policy that the fatigue failure life of the solder joints could be evaluated by the application of the Paris' law.
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Kenya KAWANO, Norio TAKEDA, Hideo MIURA, Mamoru IIDUKA, Kenji KOYAMA
Article type: Article
Pages
251-252
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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A method for evaluating vibration fatigue of the wire in gel-mold module was studied. First, the dynamic viscoelasticity testing of a gel was carried out, and the dependence of gel elasticity on frequency was clarified by using a time-temperature conversion law. Based on this result, a vibration fatigue testing and a vibration-stress analysis of the wire in gel were carried out, and the vibration fatigue characteristic of the wire in gle was clarified.
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Naotaka Tanaka, Takashi Nakajima, Chuichi Miyazaki, Yasuyuki Nakajima
Article type: Article
Pages
253-254
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Wire bonding-that is, connecting LSI chip pad and an interposer substrate by a thin gold wire-is one of the main process in assembly of LSI packages. However, producing a fine-pitch wire bonding, such as that with less than 50-μm pitch, faces some problems. For example, a high-rigidity wire prevents wire flow during molding process, but deteriorates the bondability between the gold ball and an alminum pad on the LSI chip in the bonding process. Accodingly, in this study, we carried out a dynamic stress analysis on a real bonding process in order to clarify the bonding mechanism. It was found that the strain distribution of gold ball bonding interface in the direction of ultrasonication is the main factor for evaluating the bondability between the gold ball and the alminum pad. It was also found that it is possible to evaluate the effect of chip damage on the wire bonding process.
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Osamu IDO, Tadashi TATENO, Shigeo ISHIKAWA, Nobutaka ITOH, Kinuko MISH ...
Article type: Article
Pages
255-256
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The strength reliability to the drop impact is important in a mobile equipment, and the impact strength reliability is evaluated by drop impact test with the product. In drop impact test of the product, it is difficult to evaluate strength with good accuracy narrowed to the solder joint parts of specific parts. If the impact strength reliability is evaluated with one part, the reliability of the solder joint part of electronic parts is quickly forecast in designing the initial stage without the mechanism element of the case etc. In this report, the result that method of the steel ball's dropping on fixed printed wiring board and giving the impact from the outside is drop impact test equivalent method is introduced.
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Hideo KOGUCHI, Takashi AKIGUCHI, Masaaki YAMAGUCHI, Hidenobu NISHIKAWA ...
Article type: Article
Pages
257-258
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Following the increasing adoption of TFT-type LCD modules in a mobile and other equipments, COG (chip-on-glass) mounting is increasingly employed instead of TCP (tape crrier package) mounting to make LCD modules smaller, thinner, and cheaper. Since the IC and LCD panel electrodes are bonded together by the conductive particles embedded in ACF (anisotoropic conductive film), the bonding conditions depend substantially on the respective characteristics of the IC electrodes and the conductive particles on the ACF. We examined the effects of the arrangement, area and material properties of IC electrodes and the profile and the effects of material properties of conductive ACF particles.
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Nagahisa OGASAWARA, Chikao KURAMOCHI, Wakako MAKIGUCHI, Norimasa CHIBA
Article type: Article
Pages
259-260
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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A micro-indentation test is useful for evaluating mechanical properties of micro-structure. But there are many effective error factors because the measurement values are very small. The influences of some factors, work-hardened surface, strain rate, temperature change. roughness and contact area change were investigated with micro-indentation tests and finite element analyses. A work-hardened surface which is made by mechanical polishing changes the properties of a non-worked material. It is important to improve the elastic modulus and the hardness by changing the calculated value to measured value. A strain rate expands a hardness and changes an elastic modulus. Measuring an elastic modulus is more sensitive to a temperature change than measuring a hardness. A surface roughness makes a measurement value dispersed because a first contact height is changed variously.
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Tadahiro SHIBUTANI, Tetsu TSURUGA, Qiang YU, Masaki SHIRATORI
Article type: Article
Pages
261-262
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Delamination between thin films is classified into two types : opening mode and sliding mode. However, these mechanisms have not been examined because it is not easy to conduct experiments of the delamination of sub-micron thin film under opening mode and sliding mode, separately. This paper aims to evaluate interface strength of the delamination of the sub-micron thin film for sliding mode, respectively. We already developed the test method for opening mode elsewhere. Test method of sliding mode is proposed and the interface strength between thin films for an LSI is. Stress analysis reveals that the singularity of shear stress causes the initiations fo delamination of sliding modes. On the basis of fracture mechanics concepts, the criterion of crack initiation for each mode is evaluated as the interface toughness. The value of fracture toughness in sliding mode is smaller than that in opening mode. It shows that it is important to evaluate the interface strength for each mode.
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Masataka HASEGAWA, Kazuhiko SASAGAWA, Masumi SAKA, Hiroyuki ABE
Article type: Article
Pages
263-264
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The atomic flux divergence due to electromigration in a passivated polycrystalline line has been formulated. The divergence has been identified as a governing parameter for electromigration damage in the passivated polycrystalline line, AFD^*_<gen> by experimental verification process. Recently, a prediction method for electromigration failure in the passivated polycrystalline line was proposed using AFD^*_<gen> and the usefulness of the method was verified through experiment. In this study, the prediction method is applied to the angled polycrystalline lines which are covered with passivation. There are few works on prediction of failure in the angled lines, though such lines are widely used in IC (integrated circuit) products. The electromigration failures are simulated when the corner position and its angle are changed. The dependency of lifetime and failure location on line shape is studied.
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Yasufumi SHIMA, Yasushi NIITSU, Daisuke YAMASHITA
Article type: Article
Pages
265-266
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The reflection type laser photoelasticity that possesses high detection sensitivity of the birefringence measurement was developed to detect the stress of the film. A He-Ne laser was used as a light source. The magnitudes of principal stress difference and the direction of the principal stress were obtained simultaneously and quantitatively using this equipment. This type of the photoelasticity has a problem that the reflected light from the surface give rise to the error of measurement. We had adopted the confocal lens set and pin hall in order to reduce the influence the reflected light from film surface on the measurement.
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Takao MIYAKE, Satoshi IZUMI, Shinsuke SAKAI
Article type: Article
Pages
267-268
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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In semiconductor devices, it is known that electrical failures are caused by the dislocation. But observation of dislocation motion in the micro-scale devices is very difficult. Therefore, it is useful for searching the source of dislocation if we can simulate the dislocation movement. In this paper, we have developed dislocation simulator and apply to the stress field caused by the intrinsic stress of the silicon-nitride thin film. We can reproduce the dependence of the dislocation generation on the temperature qualitatively.
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Kiyoshi MIYAKE, Akihisa KUROYANAGI
Article type: Article
Pages
269-270
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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It is well known that a warpage phenomenon of LSI package is influenced by thermal and chemical shrinkage, in the meantime; there are few reports which study a chemical shrinkage for the stress analysis. In this report, a chemical shrinkage was defined as a function of temperature same as a coefficient of thermal expansion, then a thermal viscoelastic warpage analysis was carried out for a BGA package in various temperature range. It was found that the calculated values had a good correspondence with the measured ones in terms of package warpage from 25℃ to 260℃. Thus, the warpage mechanism became clear through the parameter analysis of material properties. In order to obtain a minimum warpage for a material designing of mold compound, the following suggestion is supported; 1) To increase Tg and to decrease CTE & 2) To reduce modulus at high temperature.
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Kouta NAGANO, Akihiro YAGUCHI, Munehiro YAMADA, Masanori SHIBAMOTO
Article type: Article
Pages
271-272
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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To determine the lifetime of solder joints in chip scale packages we conducted cyclic-bending, heat-cycle, and impact-bending tests. We used Sn-3Ag-0.5Cu solder and Sn-37Pb solder for the evaluation. The cyclic-bending and the heat-cycle tests showed that the lifetime of Sn-3Ag-0.5Cu solder joint was approximately twice that of Sn-37Pb solder joint. On the other hand, in the impact-bending test, the lifetime of Sn-3Ag-0.5Cu joint was shorter than that of Sn-37Pb solder joint due to interfacial crack growth.
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Hidehisa SAKAI, Qiang YU, Masaki SHIRATORI, Msanori MOTEGI
Article type: Article
Pages
273-274
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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It is concerned that residual stresses of solder joints in package assembly process are small because of solder joint stress relaxation. However, lead free solders are developed and applied to electronic devices today. It is uncertain that we can neglect solder joints residual stresses in lead free assembly process. Therefore, authors consider effects of package assembly process (reflow process) for solder joint reliability by using FEM analysis.
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Kenji HIROHATA, Minoru MUKAI, Noriyasu KAWAMURA, Takashi KAWAKAMI, QIA ...
Article type: Article
Pages
275-276
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The response surface approximation with uncertainty can be updated using a new method based on Bayes theory for the purpose of estimating the reliability more accurately in combination with data of numerical experiments. Furthermore, it is indicated that in the case that some response surface approximations for design space were stored and many sampling data from these approximations can be generated easily, the information of the design variables such as interaction among variables can be extracted and identified by applying various response surface models with many interaction terms actively.
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Toshihiko SAYAMA, Takao MORI, Takahiro OHNISHI, Yoshiaki NAGAI, Takesh ...
Article type: Article
Pages
277-278
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Sn/3.5Ag eutectic solder is one of the most elemental materials among the various Sn/Ag or Sn/Ag/Cu lead-free solders. In order to evaluate the thermal fatigue crack initiation by microstructural observation of the solder, a series of thermal cycle tests was carried out by using some PCBs on which resistance chips were mounted. Consequently, noting that dispersing Ag_3Sn phase grows, the microstructural evolution is quantified by phase growth parameter S that is defined by average phase size to the 4th power d^4. Additionally, a power law relation exists between S and number of cycles N and enables us to evaluate the thermal fatigue crack initiation of the solder joints.
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Toshihiko SAYAMA, Takao MORI, Satoko YAMAZAKI, Yoshiaki NAGAI, Takeshi ...
Article type: Article
Pages
279-280
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Recently, Sn/3.0Ag/0.5Cu solder has been noted as one of the most practical lead-free solder. In order to investigate the relation between thermal fatigue crack initiation and microstructural evolution, a series of thermal cycle tests for Sn/3.0Ag/0.5Cu solder joints was carried out by using some PCBs on which resistance chips with different sizes were mounted. Additionally, microstructural observation of the joints was carried out by SEM, and average size of Ag_3Sn phase d was measured by image processing. Consequently, the phase grows as a number of thermal cycles N increases, and the phase growth is greatly influenced by both temperature and strain change. The relation between N and phase growth parameter S, which is defined by d^4,enable us to evaluate the thermal fatigue crack initiation of the solder joints.
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Yoshiharu KARIYA, Masahisa OTSUKA
Article type: Article
Pages
281-282
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Creep data of eutectic tin-silver alloy at temperatures between 298K and 398K has been analyzed using the modified theta projection concept instead of the steady state creep constitutive equation in following formula : ε_<cr>=A{1-exp(-*)}+B{exp(*)-1}, where A, B and α are constants to be experimentally determined. The equation well describes the creep curves of the eutectic tin-silver alloy up to tertiary stage. All constants exhibited power law type relation to the applied stress. The rate constant α has high stress exponent which is attributed to the dispersion strengthening. The rate constant α and the strain factor B only showed temperature dependence, while the strain factor A was independent of temperature. The activation energy for α was 65kJ/mol at low stress and 90kJ/mol at low stress. The energies suggest that the dislocation pipe diffusion and the lattice diffusion are predominant at high stress and low stress, respectively.
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Hiroyuki TAKAHASHI, Takashi KAWAKAMI, Minoru MUKAI, Mineo KOBAYASHI, N ...
Article type: Article
Pages
283-284
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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The fatigue life estimation on micro solder joints is one of the most critical technology for the reliable IC packages. For the accurate estimation of the thermal fatigue life based on the finite element analysis, an inelastic constitutive model which can describe the time dependent deformation has been required. In this study, in order to investigate the applicability of the proposed constitutive model for Sn-Ag-Cu lead-free solder, the finite element analysis was carried out for the solder joint in a quad flat package. As a result, it was found that the inelastic deformation of the lead-free solder was successfully simulated.
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Tomoko MONDA, Keiji IUCHI, Satoshi SOMIYA
Article type: Article
Pages
285-286
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Sizing has been ever considered to spread wholly in resin, but its distribution has not been clear. Dyeing of FRP that was different in amount of sizing with acid dyestuff was applied to attempt visualizing the distribution of sizing in FRP, and revealed it. In result, it was found that sizing didn't wholly spread in resin. When amount of sizing is much, most sizing was around of fiber strands. Difference in amount of sizing made difference in distribution of sizing, which effected on tensile strength. SMC that contained the smallest amount of sizing had the smallest tensile strength. Therefore, it was found that sizing around strands made large tensile strength of FRp.
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Tetuo UEDA, Kazuo YAGI, Masataka TOKUDA
Article type: Article
Pages
287-288
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Recently, high polymer hydrogel is applied to various fields, and is put in practical use. Gel causes volume change in reversible by changing surrounding environment (pH, an electric field, solvent composition, temperature) etc. Because its hardness is comparatively high, it pays attention to PVA gel as an actuator material. But, because reactivity was poor, PVA made it have reactivity by mixing copolymeric PVA. Degree of swelling increased as a result. It can be said that it is excellent as an actuator material from this result about the copolymeric PVA.
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Shinji YOSHIDA, Kazuo YAGI, Masataka TOKUDA
Article type: Article
Pages
289-290
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Recently, magnetism fluid is attracted attention since it has fine particle and magnetic property from engineering and medical field. In this study, there are purposes that the application of magnetism fluid as bio-material. Therefore, samples created by this study need the biocompatibility and dispersion stability. And samples are formed as magnetic fine particle is coated by saccharide (i.e. magnetite is selected as the core material and monosaccharide is selected as covered material). If medication in the living body is taken into consideration, problem is control of particle diameter. So, synthesises were performed by lower molecular weight of saccharides. Synthetic method is coprecipitation, particle diameter is measured by DLS.
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Yusuke KIKUCHI, Yoshifumi ITO, Hitomi KATO, Satoshi SOMIYA
Article type: Article
Pages
291-292
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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Although fiver reinforced plastics (FRP) have many characteristics, when it was discarded, the reduction to nature is prevented and a lot of waste causes destruction of environment. Therefore, it is necessary to treat wasted FRP by suitable method. Then, the epoxy resin that is matrix of FRP was carbonized, and FRP tried recycling by using it as carbon material. In this study, change of the molecular structure was analyzed by FT-IR spectroscopy until it results in carbonization. As a result, the resin was fluidized at 300℃ and carbonized at 350℃ or more. It tried producing recycle fiver reinforced carbon material based on this knowledge. It had efficient mechanical properties.
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Qiang LIU, Eitoku NAKANISHI, Yutaka SAWAKI, Kiyoshi ISOGIMI
Article type: Article
Pages
293-294
Published: September 20, 2002
Released on J-STAGE: August 01, 2017
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