-
Article type: Cover
Pages
Cover1-
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App1-
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App2-
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App3-
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Index
Pages
A1-A7
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Yoshihiro IUCHI, Fumihiro SUZUMURA, Rongguang WANG, Suketsugu NAKANISH ...
Article type: Article
Session ID: G0100-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The wetting characteristics of micro water droplets on natural mica were observed with an atomic force microscope (AFM) in AC non-contact mode. The purpose of this paper is to investigate the influence of long-range van del Waals force and contact line tension in the wetting characteristics of micro-droplets. It might explain the observed higher wettability for micro-droplets than macro-droplets.
View full abstract
-
Daisuke TANAKA, Mariko NAKAMURA
Article type: Article
Session ID: G0100-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Brownian dynamics simulation on aggregation of submicron particles was conducted and fractal dimensions of aggregates were calculated in order to estimate aggregate size and shape quantitatively. A Langevin equation, that included fluid resistance, random force, and gravity, was solved. Three models were employed for particle aggregation: DLA(Diffusion-Limited Aggregation) model, a model in which many particles moved simultaneously and formed one aggregate, and a model in which many particles and aggregates moved simultaneously and formed aggregates. As a result of DLA model, fractal dimension increased with decrease in particle size and increase in ambient temperature. Particle size more greatly affected aggregate shapes than ambient temperature. The aggregate shape changed depending on the model for aggregation.
View full abstract
-
Takahiko KAWAMORI, Suguru KAWAMURA, Takashi GOTO, Masayuki NAKAMURA
Article type: Article
Session ID: G0100-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this research is generation of stepping points for walking robot in obstacle environment based on the optimality of motion. A walking robot is assumed as a quadrupedal locomotion type and obstacles in a route are recognized to the extent necessary. There are obstacles with various sizes and configurations in human activity space. It is difficult to generate optimum stepping points for these patterns. The neural network learns stepping point parameters and corresponding obstacle environment to output the stepping points for the obstacle environment recognized by the robot vision. Stepping points are optimized by genetic algorithm and learned by neural network. The input data is the obstacle environment parameters that are generated by the genetic algorithm. The output data of the neural network is the stepping points. Workable stepping points are obtained by using proposed method.
View full abstract
-
Toru Inaba, Osamu Kogi, Taku Sakazume, Yoshihiro Yamashita, Shinya Mat ...
Article type: Article
Session ID: G0100-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Analysis program of magnetic particles movement has been developed for the purpose of the prediction of path of magnetic particles in a flow cell of an immunoassay detector. Magnetic particles flow into the flow cell composed of a channel, electrodes, and a magnet. These particles are captured by the magnet below the electrode. It is very important to calculate and predict the path of particles for a design of high-precision detector. Forces such as drag force, pressure gradient force, gravity force, and magnetic force are accounted for the magnetic particles. Comparison between computational and experimental particles distribution on the electrode were made, and predicted adsorbed particles distribution is good agreement with experimental one. Proposed methods and developed program are very effective for the prediction of magnetic particles movement.
View full abstract
-
Kazuma MIURA, Jun TOYOTANI, Kazuhiko KAKUTA
Article type: Article
Session ID: G0100-1-6
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The present shows incompressibility fluid using Moving Particle Semi-implicit method . It aims to develop a steady method for incompressibility fluid by Moving Particle Semi-implicit method. In general, Moving Particle Semi-implicit method is very used for the flow analysis with shape. Incompressible Fluid Flow is analyzed. It is investigated what solution and what problem you cause. As for the particle method, when a past reports is investigated, the thing that the value of pressure causes the vibration easily is reported. Finite difference method understands a numeric vibration is similarly caused, and has solved this problem. Therefore, the stabilization technique can be similarly developed for Moving Particle Semi-implicit method.
View full abstract
-
Masaya Takahahsi
Article type: Article
Session ID: G0100-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Aluminum alloy plates are commonly used in automobile, train, aircraft and so on which lightweight is required. However, lower costs and lighter weight materials are demanded. In order to satisfy the demand for lightweight without changing the material, it is necessary to raise the second moment of area to increase stiffness. The purpose of this study is creating isotropic plate and thin shell structures with high stiffness. In this paper, shell structures which have the large second moment of area in arbitrary cross sectional dimensions was developed. The FEM analysis indicated that the developed shell structures made the weight of plates less than half under equivalent stiffness condition.
View full abstract
-
Changcheng SHAO, Toshiya IINUMA
Article type: Article
Session ID: G0100-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The conventional Galerkin FEM may fail to approximate the original differential equation locally when unstructured linear triangular meshes are used. This problem arises from the inconsistency between the integrals of the source team and the other terms. This research tries to solve this problem by introducing the concept of nodal domain for the source term and integrating the source term only within an element at the same time. This scheme reaches second-order consistency between the diffusion terms and the source term. The effectiveness and reasonability of our scheme are investigated numerically and theoretically. Improved accuracy is obtained for unstructured right triangular meshes and unstructured obtuse triangular meshes.
View full abstract
-
Takeshi TANE, Takeshi UCHIDA, Kiyokazu KIMURA, Hiroki HAMANO
Article type: Article
Session ID: G0100-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper presents analytical solutions for an elastic medium due to stress release method using cylindrical measuring device. It is assumed that the medium is an anisotropic elastic body, while other layers are isotropic. And various three-dimensional loadings are treated. Also, it is possible to exactly apply this theory to measurements by small-diameter overcoring. Therefore, this paper can be expanded past analytical studies which assumed large-diameter overcoring. In numerical calculations, effects of hardness of measuring device or overcoring radius on measurement results are discussed.
View full abstract
-
Makoto HASEGAWA, Mitsunari KITAYAMA, Masayuki NAKAMURA
Article type: Article
Session ID: G0100-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper proposes a method of inverse analysis for identification of an impact load using selected strain data. Taking the dynamic behavior of structure under the impact load is comparatively easy if many sensors and high precision measuring devices are available. On the other hand, if the dynamic behavior can be obtained by a few strain data with lower accuracy, the method has advantages to measuring cost and efficiency. In this study, fuzzy clustering is used for selecting and picking up the strain data for the learning of the neural network. As a result, it is shown that the proposed method using fuzzy clustering has an advantage on the inverse analysis.
View full abstract
-
Ryoichi SHIBATA
Article type: Article
Session ID: G0100-2-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
CAE system to support manufacturing, education and training make the case, the cost becomes an issue. Therefore, available for free use by open source systems CAE "DEXCS + FLUSH" was constructed. This system can be built and ready on a normal PC, USB delivers just start grid system that supports large-scale parallel numerical analysis. With structural analysis and fluid analysis capabilities, has been released as Open Source. This report is built on open source and CAE analysis to verify the accuracy of the system, discuss the efficiency of large-scale parallel structural analysis.
View full abstract
-
Masahiro UCHIMURA, Hirohisa KIMACHI, Kazunari FUJIYAMA, Wataru OTA
Article type: Article
Session ID: S0306-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Damages in thermal barrier coatings (TBCs) exposured under high temperature are accumulated, and ultimately the spallation of top coats (TC) in TBCs is occurred. Main factors of these damages are formation of thermally grown oxide (TGO) and resintering of TC. In the present study, damages and microstructures in TBC under various thermal exposure conditions were evaluated by using Raman microspectroscopy, Scanning Ion Microscope (SIM) and Electron Backscattered Diffraction (EBSD). In TGO layers, Raman spectrum of α-Alumina was obtained, its crystallinity was varied with thermal exposure time. Similarly, thickness of TGO layer was varied with thermal exposure time. The change of TGO thickness corresponded to that of crystallinity of TGO. On the other hand, oxide was observed in bond coat. Its amount increased with thermal exposure time to 100h, above which it keep constant. Besides, 3 dimensional microstructure of TC layer were reconstructed by FIB serial-sectioning and EBSD method, TC layers had crystal with high-aspect ratio.
View full abstract
-
Kazuto HIJIKURO, Toshiki TSUBOI, Kazunari FUJIYAMA, Hirohisa KIMACHI
Article type: Article
Session ID: S0306-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
EBSD(Electron BackScattering Diffraction) observation was conducted on creep damaged and creep-fatigue damaged Mod.9Cr steam pipe steel. Creep damage was imposed for the time fraction as 0.1, 0.2, 0.5, 0.8 and 1 at 650℃, 1OOMPa as well as creep-fatigue for the cycle fraction as 0.1, 0.25, 0.5 and 1 at 650℃, l%strainrange and 10min tensile strain hold. The longitudinal mid-section of specimen was observed and IQ(Image Quality) maps, IPF(Inverse Pole Figure) maps and KAM(Kernel Average Misorientation) maps were obtained for the each damage level. Area averaged parameters of KAM: KAM_<ave> showed gradual decrease in creep and initial decrease in creep-fatigue. Boundary spacing obtained from KAM map increased at early stage of damage process. By combining those two parameters and pixel step size, the "Modified misorientation parameter M_ε" was introduced and showed linear correlation with permanent strain. After the initial increase of creep-fatigue plateau stage for M_ε was recognized suggesting the onset of crack propagation dominated process. Thus, EBSD observation was revealed as a powerful tool for analyzing damage process as the quantitative measure of accumulated strains at sub-grain size level.
View full abstract
-
D. Kobayashi, M. Miyabe, Y. Kagiya, Y. Nagumo, R. Sugiura, T. Matsuzak ...
Article type: Article
Session ID: S0306-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The Ni-base superalloy IN738LC developed as a heat-resistant material for gas turbines is used under the conditions of creep-fatigue interaction. To maintain operational safety and minimize maintenance costs, it is necessary to clarify the characteristics of fracture life taking into account the effect of both creep and fatigue interaction on fracture life. In this paper, an in-situ observational testing method under the conditions of creep-fatigue interaction was conducted using IN738LC, and the effects of cycle- and time-dependent mechanisms on the fracture life were investigated. As a result, the multiple effects of creep and fatigue on fracture life t_f were clarified by a three-dimensional curved surface representation of the load frequency characteristic. Furthermore, the concentration of damage by the effect of fatigue and the diffusion of damage by the effect of creep are observed by microscopic crystal orientations analysis using electron Backscatter Diffraction.
View full abstract
-
Keiji Kubushiro, Yohei Sakakibara, Kyohei Nomura, Satoshi Takahashi
Article type: Article
Session ID: S0306-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
EBSD analysis was conducted about stainless steels strained by tensile tests. GOS ( Grain Orientation Spread parameters are expressed in a straight line without regard to grain size. KAM (Kernel Average Misorientation) parameters were expressed in a straight line only same grain size. At the same plastic strain, larger grain size specimens showed small KAM parameter.
View full abstract
-
Shingo TAKIGUCHI, Setsuo MIURA, Michiaki KOBAYASHI, Junichi SHIBANO
Article type: Article
Session ID: S0306-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Tomonori OGAWA, Toshihiro OHTANI
Article type: Article
Session ID: S0306-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We evaluated the creep damage of Cr-Mo-V steel (JIS-SNB16) from the evolution of a nonlinear acoustics with Electromagnetic Acoustic Resonance (EMAR). EMAR is combination of resonant acoustic technique with a non-contact electromagnetic acoustic transducer (EMAT).The change of nonlinear acoustic parameter during creep damage shows the peak of around 30% of predicted creep life corresponds to evaluation of material microstructure. The relationship between A_2 and A_1^2 is liner function. The NLU measurement with EMAT has a potential to assess the damage advance and to predict the creep life of metals.
View full abstract
-
M. OKAZAKI, M. TADA, S. YAMAGISHI, S. SAKAGUCHI
Article type: Article
Session ID: S0306-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Friction Stir Welding (FSW) technique was proposed as a new repair technique for Ni-base superalloys. At first, a butt welding joint between of Al alloy 6063 and INCONEL 758 tried to be fabricated by a FSW technique. The optimized welding condition was also explored combining a wide varieties of welding parameters. In order to assure the conditions, the mechanical properties of the welded joint thus optimized were also evaluated.
View full abstract
-
Kazuhiro OGAWA, Abreeza Manap, Dowon Seo, Yuji Ichikawa, Yoshiaki Nish ...
Article type: Article
Session ID: S0306-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The cold spray (CS) technique is known as a new coating technique. It has many advantages, i.e. dense coating, high deposition rate no phase transformation and low oxidation. The CS technique was applied to make a bond coating (BC) for a thermal barrier coating (TBC). In this study, the TBC with cold sprayed bond coat (CS-BC) and a TBC with conventional low pressure plasma sprayed BC (LPPS-BS) were prepared. High temperature oxidation behavior under stress loading was evaluated for these samples. As a result, the high temperature oxidation behavior of the TBC with CS-BC is approximately-same or slightly excellent compared to that of the TBC with LPPS-BC.
View full abstract
-
Takahiro MITSUI, Setsuo MIURA, Junichi SHIBANO, Michiaki KOBAYASHI
Article type: Article
Session ID: S0306-3-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Akihiro MATSUDA, Soichiro TATEIWA, Chihiro ITO, Toshiari SAEGUSA
Article type: Article
Session ID: S0306-3-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, a prediction method of compression set of O-ring in packages containing radioactive materials using by numerical simulation was investigated. In the lid of the MOX fuel transport packages, the EPDM (Ethylene Propylene Diene Monomer) O-ring was applied to confine the radioactive subset. In order to examine mechanical thermal stress relaxation tests were conducted. The numerical simulation was conducted by the Maxwell type viscoelastic models, elements of which were composed by hyperelastic springs and linear dumpers. As a result, the nonlinear viscoelastic model was applicable to the prediction of the compression sets of EPDM O-ring for the MOX fuel transport packages.
View full abstract
-
Kenji IKAIDA, Akihiro MATSUDA, Hiroshi MORII
Article type: Article
Session ID: S0306-3-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, we conducted durability tests of V-seals to propose a new maintenance assessment method. V-seals are fiber-reinforced rubber components to seal the mechanical shaft from fluid. They are used at hydraulic power generator and abraded by rotating shaft. Durability tests were conducted by the device reproducing usage condition of the V-seals in the generator. After the durability test, V-seals were abraded intensely. Nevertheless, from the leak tests results, these V-seals had maintained high seal performance. Then leak tests of pre-cut V-seals were conducted. These V-seals are the ones that abraded state was imitated. From the tests results, the relation between wear volume and seal performance was clarified.
View full abstract
-
Yuta Tsuchiya, Setsuo MIURA, Jun-ichi SHIBANO, Yoshiharu Ozaki, Michia ...
Article type: Article
Session ID: S0306-4-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Katsuyuki TOKIMASA
Article type: Article
Session ID: S0306-4-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The 90 deg out-of-phase straining axial/torsional fatigue tests were conducted on thin-walled tubular specimens of 2.25Cr-1Mo steel at 823 K in air, and the effects of strain hold time on the fatigue behavior of the material were examined. Three trapezoidal strain waveform, TH (tension hold), CH (compression hold) and TCH (tension and compression hold), were used. It was found that axial (or torsional) stress tends to be drastically relaxed when torsional (or axial) strain is changed while axial (or torsional) strain is kept constant. It was examined whether or not the life prediction method based on the strain range partitioning concept for nonproportional loading proposed by the authors can be used to explain the observed hold time effects.
View full abstract
-
Yusuke SAKAGAWA, Ryota SAKAI, Keisuke TANAKA, Kazunari FUJIYAMA
Article type: Article
Session ID: S0306-4-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Crack propagation tests of lead-free solder were conducted using center-notched plates under three cyclic tension-compression load controlled waveforms: pp wave is fast loading and unloading, cp-h wave is tension-hold and cc-h wave is tension and compression hold. Creep crack propagation rate of cc-h and cp-h wave shape was calculated by the subtraction of fatigue crack propagation rate from total crack propagation rate. The relationship between creep crack propagation rate and creep J-integral showed parallel two lines for cc-h and cp-h wave shares, showing 10 times faster for cp-h than cc-h. Microscopic crack propagation path was examined with SEM in correlation with the microstructual change measured by EBSD. Grain fragmentation and KAM (karnel average misorientation) observed near the crack tip with EBSD changed depending on the wave form.
View full abstract
-
Yuki SATO, Shuhei NOGAMI, Akira HASEGAWA
Article type: Article
Session ID: S0306-4-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Effects of irradiation damage on the micro-crack initiation following the slip band formation and growth under low cycle fatigue in the proton-irradiated SUS316L austenitic stainless steel was investigated for improving the prediction method of the micro-crack initiation life under irradiation. The slip band spacing and the micro-crack initiation life of the specimen irradiated up to 0.25 dpa at 230℃ were about twice larger and one-fifth shorter than those of the unirradiated specimen, respectively. The micro-crack initiation in the unirradiated specimen occurred at the grain boundary, trans-crystalline, twin boundary and slip band. While, that occurred only at the twin boundary and slip band in the irradiated specimen. The number density of the slip band increased rapidly at the micro-crack initiation life ratio of 0.2〜0.4, and then it tended to saturate. These trends were independent of the irradiation.
View full abstract
-
Shuhei NOGAMI, Takamoto ITOH, Hiroyasu TANIGAWA, Eichi WAKAI, Arata NI ...
Article type: Article
Session ID: S0306-4-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The effect of specimen size and specimen shape on the low cycle fatigue life and the micro crack growth behavior under low cycle fatigue in the reduced activation ferritic/martensitic steel, F82H, were investigated using a miniature specimen to develop the fatigue life evaluation method using it. The effect of specimen size on the fatigue life from 10^3 to 10^4 cycles level was almost negligible for the round-bar specimens. While, the effect of specimen shape was clearly observed in the hourglass specimen. The shorter fatigue life at relatively low strain range and slight longer fatigue life at relatively high strain range than the standard specimen were observed. The micro crack growth behavior of the miniature hourglass specimen in F82H was similar to that of the standard specimen observed in the various metals.
View full abstract
-
Junichiro YAMABE, Takashi MATSUMOTO, Shin NISHIMURA
Article type: Article
Session ID: S0301-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Due to exposure of high-pressure hydrogen gas to a sealing rubber material, such as an O-ing, internal cracks sometimes occur by decompression, and consequently cause serious leakage of the hydrogen gas. Therefore, it is important to detect the internal cracks in an early stage of fracture. From this viewpoint, an acoustic emission (AE) method was applied in order to detect internal fracture of the sealing rubber material by high-pressure hydrogen decompression. According to preliminary tests, while AE signals were hardly detected at a tensile test in air, those were detected at a static crack growth test in air. This result implies that the AE signals are mainly generated during crack initiation and growth. The AE measurement of hydrogen-exposed specimens was also conducted. Internal cracks of the hydrogen-exposed specimens can be detected by the AE method. When crack damage became more serious, the count and amplitude of the AE signals increased.
View full abstract
-
Tomofumi Amano, Atsushi Hosoi, Yang Ju
Article type: Article
Session ID: S0301-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, we report results of measuring stress corrosion cracking (SCC) and evaluating its depth on the surface of Ni-base alloys, utilizing microwaves. An open-ended coaxial line sensor was used to increase the spatial resolution. The working frequency was 110 GHz and the standoff distance between the sensor and the sample was 60 μm. The distribution of SCC was obtained by microwave imaging. By measuring the amplitude of reflection coefficient, detection of SCC was achieved and V-shaped and W-shaped characteristic signal was obtained. The equation to evaluate SCC depth was proposed. Consequently, the distribution of SCC depth along the crack length was evaluated using the measured amplitude difference.
View full abstract
-
Takatsugu NAGAHAMA, Takahiro YANO, Atsushi HOSOI, Yang JU
Article type: Article
Session ID: S0301-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The technique to heal a fatigue crack in a stainless steel by controlling a high-density electric current field was developed. The high-density electric current field can be caused at the tip of the crack using extremely adjacent electrodes. As the experimental results, it was observed that the crack closure and the bridging on the crack surface at the vicinity of the crack tip were caused due to applying the high-density pulse current in the specimen. It was evaluated quantitatively by Paris law that the propagation of the healed fatigue crack delayed temporally.
View full abstract
-
Takahiro Yano, Takatsugu Nagahama, Atsushi Hosoi, Yang Ju
Article type: Article
Session ID: S0301-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A technique to heal a fatigue crack in a stainless steel based on the control of the high-density electric current field was developed. The high-density electric current field was caused at the crack tip by applying a pulse current through the electrodes near the crack. The crack surface was observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM) before and after the application of the high-density pulse current in order to examine the effect of the high-density electric current field on the fatigue crack. The experimental results show that the fatigue crack was closed and the surface having the slips at the vicinity of the crack tip became smoother by the electrical stimulation.
View full abstract
-
Koichiro Kawashima, Ryusuke Imanishi
Article type: Article
Session ID: S0302-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The validity of the higher harmonic imaging technique is demonstrated for detecting and sizing IGSCC in Ni-based alloy weld with buttered region. The IGSCCs in the buttered and welded regions were imaged by the normal or oblique incidence techniques. The depth of the IGSSC estimated by higher harmonic images agrees within 4mm with tat measured by optical microscope..
View full abstract
-
Taesuke FUKUI, Toshihiro ITO
Article type: Article
Session ID: S0302-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The reflected wave at the ultrasonic NDT is scattering because the shape of SCC is complex, and it is difficult to evaluate SCC. The scattering wave not received easily by one probe can be expected to be detected by combining multiple receivers. In addition, the improvement of the spatial resolution can be expected by aperture synthesis using received wave type obtained by multiple transducers. In this study, we examined the effect of multiple transducers by using FEM nonlinear ultrasonic wave propagation analysis.
View full abstract
-
Naoki MATSUDA, Shiro BIWA
Article type: Article
Session ID: S0302-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Despite its importance in nonlinear ultrasonic measurements, the harmonic generation in Lamb wave propagation is a difficult issue due to the dispersive nature and the multiple mode existence. Based on a systematic analysis of Rayleigh-Lamb frequency equations, the frequencies of Lamb waves which may cause cumulative harmonic generation have been derived in this study. The derived formulas giving angular frequencies, wave numbers, phase velocity and group velocity of the cumulative Lamb modes are given in terms of longitudinal wave velocity, transverse wave velocity, plate thickness and two positive integer numbers. The phase velocity of the fundamental and cumulative harmonic modes is dependent on the ratio of two integer numbers, and there are infinite numbers of such phase velocities at which cumulative harmonic generation is possible. These conclusions can be applied to any elastic material which is isotropic and homogenous.
View full abstract
-
Kazumi WATANABE
Article type: Article
Session ID: S0302-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A simple mathematical model for stick-slip motion is introduced and SH-wave response to a moving source with the stick-slip motion is discussed. After getting exact expressions for the dynamic response, Doppler effects induced by the stick-slip source motion are derived and it is shown that the stick-slip motion produces the Doppler frequency shift since the source motion includes two velocity parameters, frequency and mean velocity of source motion. Some numerical examples for the response are shown in graphical forms and it is also shown that the lowest frequency term has the dominant contribution to the response
View full abstract
-
Yoshinori Kamiyama, Katsuya Ooyama, Tsuyohsi Mihara, Hatsuzo Tashiro
Article type: Article
Session ID: S0302-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In industrial ultrasonic inspection, closed defects (cracks) result in misdetection or underestimation in sizing of the defects. Nonlinear ultrasound especially sub-harmonic ultrasound has been expected to detect closed defects due to the large displacement of incident wave. However, applicable displacement of incident ultrasound at defect is 100 nm peak-to-peak at most which considered insufficient comparing to the industrial crack tip displacement. In this study, we focused on phased array technique, and fabricated an 8ch phased array system which can excite 600Vp-p successive wave. We observed the fundamental travelling behavior of ultrasound combined with the prototyped transducers and investigated the availability of the phased array techniques to enhance the amplitude of incident waves.
View full abstract
-
Junji TAKATSUBO, Shinichi MORIYA
Article type: Article
Session ID: S0302-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A generation laser scanning method for onsite visualization of ultrasonic wave propagations was developed. We applied this method to nondestructive inspection of cracks in a rocket combustion chamber. From the measured dynamic images of the mockup specimen, we could observe the crack echoes on the inner wall. The detected sizes of crack echoes correspond well to the real sizes of the cracks. These results indicate that this method can be effective for nondestructive inspection of rocket combustion chambers.
View full abstract
-
Sho WASHIMORI, Takahito KATSUHARA, Tsuyoshi MIHARA, Yuki NAGAI, Hatsuz ...
Article type: Article
Session ID: S0302-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The photoelastic ultrasonic visualization method is predominant experimental technique to observe the ultrasonic travelling behaviors. We have developed new visualization system using pulse laser as a light source to improve the resolution of the conventional visualization image. In this study, we demonstrated the advantage of the pulse laser visualization system to apply the sound field observation for 50MHz Phased Array system which is used for the inspection of semi conduct products.
View full abstract
-
Yuki NAGAI, Tsuyoshi MIHARA, Hatsuzo TASHIRO, Tomoyuki SAWAYAMA, Kazuh ...
Article type: Article
Session ID: S0302-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Ultrasonic measurement has been used for liquid flow velocity measurement in industrial pipe structure. Though a pitch-catch measurement from outer surface of a pipe is required, S/N ratio of the transmitted echo through pipe become worth due to the complicate layout of the pipe and ultrasonic wedge. Then in this study, we applied large scale three dimensional FEM analyses for the pitch-catch measurement of the pipe structures and accurate ultrasonic travelling behaviors were investigated. Especially for pipe material, difference of the transmitted and reflected echoes between steel pipe and PVC pipe were investigated. As the result, due to the difference of the impedance of steel and PVC, large differences were observed in ultrasonic propagation behavior which relate to SN ratio of the industrial flow velocity measurement in pipe.
View full abstract
-
Yoshikazu NAKAHARA, Tatsurou MORITA, Yoshimiti FUJII, Masanori OKANO
Article type: Article
Session ID: S302-3-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This study was conducted to establish a nondestructive inspection method based on ultrasonic echo measurement. The GFRP model material was immersed into hot water maintained at 371 K during 1 day to 28 days. The progress of damage was investigated from the surface and on the cross-section in detail. At the same time, ultrasonic echo was measured at all area of the material from the surface. As a parameter, the integrated value of echo level per unit time V^^- value was used. The results showed that the damage condition of the GFRP material such as density of delamination and its progress can be adequately evaluated by the distribution of V^^- value.
View full abstract
-
Ayaka HARA, Tomohiro MORISHITA
Article type: Article
Session ID: S0302-3-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The ultrasonic velocities due to plastic deformation were measured and the summation of squared velocities, which was independent of texture, was calculated. The change in the summation in as-received copper, which has work hardening and dislocation, was smaller than annealed one. After giving 40% plastic strain, the specimens were held in 30 minutes under various annealing temperatures. And then the summation of squared velocities were measured. The summation increased rapidly around 300℃ which was identical with the recrystallization temperature. Moreover, 400℃ or more, the summation almost showed con- stant value. It is known that the temperature, 400℃, makes anneal in copper completely. Therefore it can be concluded that the summation of squared velocities has a connection with dislocation.
View full abstract
-
Md. Nurul Islam, Yoshio ARAI, Wakako ARAKI
Article type: Article
Session ID: S0302-3-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The objective of present study is to develop an evaluation method of low cycle fatigue crack growth from PSBs of stainless steels using ultrasonic back reflected wave. Behavior of back reflection intensity change from the surface due to fatiguing was measured. It was found that the decrease of back reflection intensity depends on the plastic strain range when the ranges are kept constant. The onset of crack growth can be predicted in the load variation condition by the linearly cumulative plastic strain and the PSB damage model proposed.
View full abstract
-
Kazunari MAKINO, Hiroshi SAKAMOTO, Shiro BIWA
Article type: Article
Session ID: S0302-3-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Regarding a hollow axle with a bore diameter of 40 mm, as developed for meter-gauge railway cars, we performed a full-scale rotating bending fatigue test on a hollow axle. Artificial flaws were previously machined on the wheel seat of the axle. We attempted to follow the echo height of artificial flaws by the in-situ ultrasonic testing during the fatigue test. Consequently, though the amount of the crack propagation from artificial flaws was negligible, the echo height altered widely according to the progress of the fatigue test. It was assumable that the transition of contact condition between the axle and wheel had affected to the reflection and transmission coefficient of ultrasonic angle beam, accordingly, the echo height altered.
View full abstract
-
Masahiro HIGUCHI, Tadaharu ADACHI, Harunobu NAGINO, Nobuhiko Yoshigaki
Article type: Article
Session ID: S0303-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We proposed a generalized shear deformation theory to accurately analyze the bending behavior of functional material plates with a simple mathematical procedure. The generalized shear deformation theory was developed using in-plane displacements expressed in terms of the transverse shear strains derived from the stress equilibrium equations of the in-plane directions. The simply supported functionally-graded plates subjected to a transverse load were analyzed to confirm the validity of the proposed theory. The transverse shear strain and stress obtained by the proposed theory showed good agreement with the exact solutions based on three-dimensional elasticity.
View full abstract
-
Shunsuke HIRATSUKA, Yuuki GOTO, Hisao HASEGAWA
Article type: Article
Session ID: S0303-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper is concerned with the stress concentration problem of an elastic plate with two slender rigid inclusions. A method of solution is presented to obtain tensile forces acting on the slender inclusions. Influences of the length and the distance between the inclusions on the tensile forces are investigated. The method of solution used here is a body force distribution method which is also called a method of fundamental solution. For this purpose, we apply the so-called Kelvin's solution in the two dimensional elasticity.
View full abstract
-
Yudai Takagi, Takuya Morimoto, Hiroshi Iizuka
Article type: Article
Session ID: S0303-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, we first determine the self-equilibrium configuration of the strand that has no excessive twists, say torque-balanced strand. It keeps the self-equilibrium configuration without any external loads, due to torque balance of contact force between filaments by geometrical and physical twist. We determine the self-equilibrium solution of the strands based on generalized Kirchhoff rod model. Filament is assumed to be a linear elastic material, and we consider both the geometrical twist such as helically wound side filaments around a core filament, and physical twist. In the formulation, we take into account the radial contact in three-dimensional space. Next, we study constitutive behavior of torque-balanced strand under tensile load. Then, we examine the effects of microscopic geometrical and material factors such as the physical twist and Young's modulus of the filament on the macroscopic constitutive behaviors of 1+n strands under tensile loading.
View full abstract
