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Published: September 12, 2009
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Article type: Appendix
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Article type: Appendix
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Published: September 12, 2009
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Article type: Appendix
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Published: September 12, 2009
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Article type: Index
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A1-A7
Published: September 12, 2009
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Shigeru AOKI, Kento Sakakibara
Article type: Article
Session ID: G0101-1-1
Published: September 12, 2009
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A new oil damper for reduction of seismic response of two story house is developed. Oil damper contains silicon oil and some shapes of materials. Oil damper is connected to the ceiling of the first story and the foundation of house. First, the effect of oil damper is examined experimentally. Spherical damper and cylindrical damper are used in experiment. It is found that peak of the resonance curve is reduced when the dampers are used. Next, two story house with the damper is modeled as a two-degree-of-freedom system. Using actual earthquake records, the response of the house is obtained. It is found that the maximum response is reduced when the dampers are used.
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Guiming Rong, Hiroyuki Kisu
Article type: Article
Session ID: G0101-1-2
Published: September 12, 2009
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Akihiro Matsuda, Kazuyuki Nakahara
Article type: Article
Session ID: G0101-1-3
Published: September 12, 2009
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In this paper, applicability of an orthotropic hyperelastic model to fiber-reinforced rubber for sealing parts used in the electric power generator was shown. The fiber-reinforced rubbers are composite materials with rubber matrix reinforced by fibers. The mechanical properties are anisotropy that depends on directions, strength and woven pattern of reinforcing fibers. A 2-dimensional finite element simulation code for the orthotropic hyperelasticity was developed to estimate the mechanical characteristic of the fiber-reinforced rubber. Material constants of reinforcing fibers and rubber matrix were obtained by tensile and biaxial loading tests experimentally. From the results of numerical simulations, applicability of developed code to the fiber-reinforced rubber for the electric power generator was shown.
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Thien Xuan DIN, Yoshifumi OGAMI
Article type: Article
Session ID: G0101-1-4
Published: September 12, 2009
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In this paper, a one-layer displacement valveless micropump which can work as a micromixer is numerically studied. The micropump consists of a pump chamber, a neck channel, an outlet channel which is perpendicular to the two opposite inlet channels. A side of the pump chamber is enclosed by a vibrating diaphragm which deforms volume of the pump chamber with time, then excites the flow from the inlet to the outlet of the pump. The attained flow rate at the outlet shows the advance of the present micropump in comparison with conventional nozzle-diffuser micropumps. The mixing performance of the devices is studied by Poincare map technique. It is observed that the mixing is enhanced with an inclined rib in the neck channel.
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Ryosuke KATO, DAIJIROH Shiraishi, Haruo ENDOH, Tsutomu HOSHIMIYA
Article type: Article
Session ID: G0301-1-1
Published: September 12, 2009
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In this study, the nondestructive evaluation (NDE) of a compound defect in the weld metal of an aluminum plate has been demonstrated using a photoacoustic microscope (PAM). The compound defect is the blowhole which occurred in the weld metal by welding. The experiments were carried out at different modulation frequencies to obtain the depth profiling by changing the thermal diffusion length. Furthermore, X-ray tomographic imaging and scanning laser microscope (SLM) were also used for comparison with the obtained PAM images. The separation of surface and internal defects were well performed by changing modulation frequency, and PAM measurement agreed well with X-ray micrograph and SLM measurements.
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Akihiro WADA, Shinya MOTOGI
Article type: Article
Session ID: G0301-1-2
Published: September 12, 2009
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A novel technique using Lamb waves has been proposed to detect impact damage of composite laminates nondestructively. Conventional ultrasonic testing requires two-dimensional scanning because the inspected area by one operation is relatively small. In this study, the availability of Lamb wave cross-scanning which consists of two orthogonal line-scanning, is demonstrated for quick detection of a localized defect. Firstly, long range scanning is conducted along the principal direction of the laminates. Then, another long range scanning is conducted along the perpendicular direction to the first one. Finally, the obtained results are multiplied orthogonally to each other to make the grayscale image of a defect. Proposed method is found to be effective to quickly obtain the rough image of impact damage.
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Yui KAWAMI, Akihiro WADA
Article type: Article
Session ID: G0301-1-3
Published: September 12, 2009
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Anisotropic damage development of hollow particle reinforced composites has been formulated based on equivalent inclusion concept. Macroscopic response of the composite including intact or cracked hollow particles is evaluated by three-dimensional finite element method to investigate the load carrying capacity of the particle, and the way to replace an intact or cracked hollow particle with an equivalent homogeneous particle is examined. Moreover, based on energy balance concept, damage development of hollow particle reinforced composites due to particle fracture is simulated to characterize anisotropic damage development. It is found that damage induced anisotropy is little affected by the hollow ratio whereas it has significant effect on stress-strain response of the composite.
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Takahiro KINOSHITA, Yuta UCHIYAMA, Takashi KAWAKAMI
Article type: Article
Session ID: G0301-1-4
Published: September 12, 2009
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Pressure-induced phase transition of perfect crystal of α-quartz-type GeO_2 was found to be 6.0 GPa at 300 K. It was also shown large volume shrinkage of approximately 12 % due to its phase transition. Under high temperature condition at 600 K and 900 K, transition pressure of perfect crystal was increased by temperature increment. Phase transition pressure of α-quartz-type GeO_2 crystal contained vacancies was decreased with increased of density of vacancies.
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Yusaku NISHIKAWA, Noriyo HORIKAWA, Yoshio HARUYAMA, Akiyoshi SAKAIDA, ...
Article type: Article
Session ID: G0301-1-5
Published: September 12, 2009
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In this paper, tensile strength of UV light irradiated and flexural damaged poly-p-phenylene benzobisoxazole (PBO) fiber were investigated in monofilament tests. The tensile tests of a monofilament were carried out at a gauge length of 12.5 mm and deformation rate of 0.5 mm/min. The flexural damage given to the fiber was introduced by wrapping the fiber around the wire. The diameter of the wire 1.25 mm, 0.625 mm and 0.325 mm. Irradiation time was 1 h and radiance was 8 W/m2. It was found that tensile strength of PBO fiber depended on the flexural damage in relatively small damage. However, tensile strength of PBO fiber depended on both the flexural damage and UV exposure in relatively small damage.
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Takuma MORIMOTO, Tsutomu ESUMI
Article type: Article
Session ID: G0301-1-6
Published: September 12, 2009
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This study analyzed the amount of stress and displacement of the load plus the double skin structure used in railway vehicles. The specimen is made using a epoxy resin. Analysis, using a static three-point bending test, the photoelastic method, stress distribution, the amount of displacement is calculated by digital image correlation method and high-speed video camera, a comparative study.
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Takaaki TERASAKI, Hisao HASEGAWA
Article type: Article
Session ID: G0301-2-1
Published: September 12, 2009
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This paper deals with the tensile force acting on a rigid circular cylindrical inclusion due to thermal stresses. A method of fundamental solution is presented for the problem. The method may be called a body force distribution method. The fundamental solution used here is solutions to the problem of an elastic infinite solid subjected to axisymmetric body forces acting along a circle. We consider the influences of the length of inclusion on the tensile force and the distributions of thermal stresses around the inclusion.
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Satoshi Takahashi, Yoshihiro Sugano
Article type: Article
Session ID: G0301-2-2
Published: September 12, 2009
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In this study, we propose functionally graded material (FGM) type electromagnetic wave absorbers for a hollow cylinder and investigate an electromagnetic noise problem and a plane-strain thermoelastic problem of those absorbers. The absorption layer with graded composition is considered as a multilayered absorption layer. We present the analytical solutions of electromagnetic and temperature fields in the FGM type cylindrical absorbers subjected to the irradiation power. The thermal stress distributions are also analyzed based on the stress function method. Numerical calculations for absorption performances and thermal stresses are carried out for the FGM type cylindrical absorbers with absorption layers composed of epoxy resin matrix and conductive titanium oxide particles.
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Kazuaki MATSUI, Takao MORI
Article type: Article
Session ID: G0301-2-3
Published: September 12, 2009
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Recently, roll forming attracts attention as a processing method of an axis and a gear used for a car. It is necessary to examine analysis of roll forming by using finite element method for improvement of processing accuracy. Therefore the purpose of this study was to examine effect of the ratio of the elasto-plastic body and rigid and mesh size on work shape. Work shape and analysis time were affected by the ratio of the elasto-plastic body and rigid.
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Shoya OKUDA, Masaaki YONEZAWA
Article type: Article
Session ID: G0301-2-4
Published: September 12, 2009
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This paper is concerned with the evaluation of structural failure probability based on numerical integrations combined with repetitive simulation procedure. A quasi ideal importance sampling joint probability density function combined in the conditional expectation is composed on the basis of the ideal importance sampling concept and the respective marginal p.d.f.s are constructed numerically by using small samples. The respective marginal p.d.f.s are renewed step by step by repetitive simulations until they converge to the quasi ideal p.d.fs and the failure probability is determined at the same time by the piecewise integrations. Numerical example shows that the proposed method gives accurate estimations with shorter processing time.
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Takashi TOYODA, Hisao HASEGAWA
Article type: Article
Session ID: G0301-2-5
Published: September 12, 2009
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This paper is concerned with the interface stresses between an elastic conical-form elastic circular solid cylinder and a conical-form rigid circular hole. We investigate on the order of stress singularity at the corner point of the interface and on the interface stress distributions. A new discretization method is presented for distributed body forces in order to improve numerical results. Influences of the tapered angle of the conical-form cylinder on the order of stress singularity are considered and the results are compared with that for two dimensional problems.
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Tetsuya KOBAYASHI, Yoshihiro SUGANO, Yusuke KUDO
Article type: Article
Session ID: G0301-2-6
Published: September 12, 2009
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The longevity of implanted artificial hip joint is dependent on wear debris caused by the transient stress occurring repeatedly on the inner hemispherical surface and its neighborhood and the change in clearance due to the deformation in UHMWPE cup. In this study, three-dimensional elastic deformations and stresses in a hemispherical acetabular cup made of UHMWPE and subjected to an asymmetric load on the inner hemispherical surface are analyzed by the use of Papkovich-Neuber displacement function. Effects of the loaded position in meridian direction on the deformations and stresses in the UHMWPE cup are quantitatively discussed based on the numerical results of the analytical solution.
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Mitsushi Ohmasa, Takayoshi Sakaki, Takayasu HIROKAWA, Takashi HAYAMI, ...
Article type: Article
Session ID: G0301-2-7
Published: September 12, 2009
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The core of the diamond cutting type was placed instead of the hexagonal core used with a usual honeycomb panel. These panels were analyzed by the finite element method when the static bend load was applied. If the area of the joint part with the surface plate is enlarged, it has been understood that the concentration of stress can be decreased, and the deflection of the panel that uses the diamond cutting type core decreases compared with the hexagon honeycomb of the same weight and the rigidity improves.
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Satoshi SHIMA, Noriyo HORIKAWA, Yoshio HARUYAMA, Akiyoshi SAKAIDA, Tak ...
Article type: Article
Session ID: G0301-3-1
Published: September 12, 2009
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It is difficult to obtain accurate compressive strength using existing methods. Direct compressive tests were performed to investigate the compressive strength of high performance polymer fiber. The compressive test pieces were manufactured by using photolithography technology. Finite element analysis was performed to decide optimal fiber length. Finite element analysis results show that fiber length less than 20 μm has much influence on stress distribution. It was found that the compressive strength of high performance polymer fiber was well represented by normal distribution. However, the scatter of compressive strength was large. This is attributed to compressive failure occurred in nonuniformly-distributed stress region.
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Takashi OSAKI, Takao MORI
Article type: Article
Session ID: G0301-3-2
Published: September 12, 2009
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It is important for the design of a high performance hose joint to consider the creep properties of the hose materials. The compressive creep tests were performed in order to examine silicon rubber which is one of the hose materials, under various load and temperature. It is clarified that the compressive properties of silicon rubber depend on the testing load but don't depend on the test temperature. Moreover, the properties of silicon rubber was compared with those of polyvinyl chloride rubber.
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Osamu TAKAKUWA, Hitoshi SOYAMA
Article type: Article
Session ID: G0301-3-3
Published: September 12, 2009
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Electrical steel sheet is using for interior permanent magnet (IPM) motor of hybrid electric vehicle (HEV) and electric vehicle (EV). In order to raise allowance rotating speed of IPM motor to realize high efficiency, it is necessary to improve yield stress of the electrical steel sheet by partially strengthening method such as peening, as the high-strength electrical steel sheet enhanced by rolling has low conversion efficiency because of high iron loss. A peening method using cavitation impact named as "cavitation peening (CP)" can improve the fatigue strength of metallic materials by introducing compressive residual stress. CP can peen the surface even through deep narrow region, as the bubbles can reach these parts and collapse where peening is required such as stress concentration area. In the present paper, the electrical steel sheet was peened by CP and the tensile test was conducted in order to demonstrate that improvement of yield stress of the electrical steel sheet for IPM motor by CP.
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Daisuke SASAOKA, Tsutomu EZUMI
Article type: Article
Session ID: G0301-3-4
Published: September 12, 2009
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High polymer materials are used in various fields, they will be expected to increase use of severe conditions in the future. However, high polymer materials have the feature that the characteristic is easy to change by the use conditions. Therefore, to expand the range of use of high polymer materials further, it is necessary to understand the fracture characteristic by the temperature dependence. In this study, specimens are three kinds of high polymer materials that inserted crack. The crack model assumed V-notch. The experiment temperatures were assumed to be a room temperature, 0, -10, -20, -30, -40 and -50℃. The dynamic stress intensity factor K_1 was determined by using caustics method and impact three-point bending test. As a result, with a fall of the temperature, the maximum value of K_1 showed the tendency to decrease in all materials.
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Masaru HARADA, Takao MORI, Satoshi USUDA, Naoko ANDO, Kazuki Nagaoka
Article type: Article
Session ID: G0301-3-5
Published: September 12, 2009
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This paper describes the evaluation method of buffer materials. Static compressive tests and falling test were performed in order to the basic compressive properties of EPS. And the finite element analysis of the drop test was carried out. The analysis result is a good agreement with the experimental result. The basic absorption of EPS can be evaluated by analysis model.
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Tetsuo Teramae
Article type: Article
Session ID: G0301-4-1
Published: September 12, 2009
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Mitsuo KOBAYASHI, Yuiti TSUJI, Katsumi FUKUDA, Takahiro IIDA, Michihik ...
Article type: Article
Session ID: G0301-4-2
Published: September 12, 2009
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One of the design methods for closing the end of a pressure cylinder is to screw down a screw plug on the threaded end of the cylinder. In this case, these is the problem of stress concentration in the threaded end of the pressure cylinder. To solve the problem, it is necessary to know accurately the load distribution on the threaded end of the cylinder. To find the load distribution on the threaded end of the pressure cylinder engaged with the taper screw plug, the following experiments are carried out. Applying the compressive load between the plug and the pressure cylinder and regarding the situation above as equivalent to the situation in which the internal pressure is applied, the load distribution is measured with the strain gauge. The effect of taper screw structure of engaged thread on the load distribution on the threaded end of pressure cylinder is presented and an expansion of design manual is discussed.
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Hidetaka NISHIDA, Kenya NAGAHISA
Article type: Article
Session ID: G0301-4-3
Published: September 12, 2009
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For high accuracy residual life assessments, and prolongation periodical inspection for high-temperature parts in boilers, there are a lot of needs finding maximum damage parts for large size pipes in boiler. We developed method that measuring by laser instrument , using elastic analysis by FEM and creep damage analysis by FEM, and observed cross section cut scrap in service plants. Result of this FEM Analysis and this section microstructure are very similar. Our created method is accuracy and and simple.
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Mitsuyasu NISHINO, Yasuyuki KATO, Masahito UEDA
Article type: Article
Session ID: G0301-5-1
Published: September 12, 2009
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The Natural Strain is obtained by integrating an infinitesimal strain increment on an identical line element. Therefore, this theory has merits that the rigid body rotation can be removed from the rotating angle of a line element and the additive law of strain on an identical line element can be satisfied. Using specimens, which have already received large pre-deformations of simple shear, the relations between direction of principal axis of stress and principal axis of strain are investigated by performing proportional loading tests for tension and torsion in an elastic region. Especially the different deformation histories, i.e. the large simple shear in a certain direction and in the opposite direction, are chosen as the pre-deformation. The co-relation between the anisotropy of elastic modulus G and the magnitude of strain hardening induced by these pre-deformation are discussed in this report.
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Masaki HONMA, Yasuyuki KATO, Masahito UEDA
Article type: Article
Session ID: G0301-5-2
Published: September 12, 2009
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A research program for investigating the thermo-elasto-plastic behavior when a laser beam is irradiated to the surface of a thin metal plate with cooling its backside is described in this paper. The residual deformation and the residual internal force occur in a thin plate after the cooling process. Therefore the plastic analyses for the second and third irradiation are more complicated. Based on the radial flow rule, the deformation increments can be decomposed into an elastic component and plasticity component on the interaction curve. In this paper, the plastic analysis for the third irradiation, which is obtained after the first and the second irradiation were performed, is treated. Especially, the distributions of the residual internal forces obtained after cooling process for the third irradiation are revealed.
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Masataka OYAMA, Yuuki KOMURO, Shigeru NAGAKI, Kenichi OSHITA
Article type: Article
Session ID: G0301-5-3
Published: September 12, 2009
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The problem of stress dependence on phase transformation has been reported in many papers. But from the view of continuum mechanics, only a few cases were analyzed and experimentally verified. In order to formulate the elastic plastic constitutive equation with the stress dependent effect on phase transformation, we carried out beinaitic transformation experiment of SCM440 under constant biaxial loading (tensile and torsional). Transformation induced plasticity (TRIP) strain components were measureed and compared with the theoretucal result.
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Jyo SHIMURA, Katsuyuki AKIYAMA, Shigeru KUROSAKI, Mutsumi MIYAGAWA
Article type: Article
Session ID: G0301-5-4
Published: September 12, 2009
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In this study, we have suggested the new joint configuration, which has a curved surface at a bonded part, and we have named it an "adhesively waved butt joint". Static tensile experiments to clarify the joint strength were carried out, using epoxy structural adhesive. While the adhesive layer in the longitudinal direction was examined on a basis of 0.1 mm in thickness, effects of adhesive thickness and adherend material on joint strength were examined in the experiments, where the adhesive thickness was changed from 0.1 to 0.05, 0.2 and 0.5mm, with the three kinds of adherend materials-aluminum alloy, mild steel and brass. As a result, load bearing property of "adhesively waved butt joint" proved to rise higher than the conventional butt joint. Furthermore, the joint strength increased as the adhesive thickness decreased. However, no regularity was recognized between the joint strength and rigidity by the adherend material.
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Makoto OHASHI
Article type: Article
Session ID: G0301-6-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The notch tip critical strain was measured at the notch tensile strength for the notched specimens with notch root radius of 0.1 mm to investigate the correlation of notch strength ratio with critical strain ratio. Critical strain ratio was defined as the ratio of critical strain at the notch tip to plastic strain at necking instability, which is numerically equal to strain hardening exponent. The plastic strain distribution below the notch tip was obtained from measurements of Vickers hardness through the calibration curve of plastic strain with hardness. The plastic constraint derived from strain localization due to low rate of strain hardening raised the critical strain ratio at the notch tip. Thus, the critical strain ratio could be a suitable measure to express the intensity of plastic constraint, and increased sharply with decreasing strain hardening exponent. Hence, the notch strength ratio, defined as the notch tensile strength to tensile strength ratio, increased with increasing critical strain ratio for the notched specimens with various strain hardening ability.
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Shouetsu ITOU
Article type: Article
Session ID: G0301-6-2
Published: September 12, 2009
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In a composite material in which two dissimilar half-planes are bonded by a nonhomogeneous elastic layer, a crack is situated at the interface between the layer and one of the two dissimilar half-planes. The stress intensity factors under tension acting perpendicular to the crack are solved. The material properties of the bonding layer vary continuously from those of the lower half-plane to those of the upper half-plane. The stress intensity factors were calculated numerically for selected crack configurations.
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Yuya MIYAZAKI, Tsutomu EZUMI
Article type: Article
Session ID: G0301-6-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Recently, laminated materials are used in many fields such as vehicles. Material combination is effective to control fracture. Laminated materials are expected to protect fracture. When a crack appear in it and develop, it may be able to stop crack developing at interface. In this study, we did impact three-point bending test and determined dynamic stress intensity factor useing caustics method and high speed camera. Result shows that material combinations are enable to control fracture.
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Masafumi SATO, Koichi KASABA, Naoto KAZAMAKI, Takashi MURAKAMI
Article type: Article
Session ID: G0301-6-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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An alternative fracture toughness test, J Evaluation Tensile Test (JETT) have been conducted. A thickness of EDM heat affected zone generated around a notch tip was measured in this research. In low carbon steel, the thickness was 50μm for the specimen with ligament diameter b=3mm. Comparing the thickness with numerically obtained high stress tri-axiality region where a fracture is likely to initiate is needed to substitute a EDM notch for a fatigue crack. The method to selected an appropriate JETT specimen size was proposed in this research.
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Shungo WATANABE, Hisao HASEGAWA
Article type: Article
Session ID: G0301-6-5
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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This paper deals with the stress concentration problem of an infinite elastic plate with a square hole under harmonically vibrating loads. The loads act at two points symmetrically located on the straight line passing through the center of hole. A method of fundamental solution is applied to the problem. Influences of radius at the corner of the hole and frequencies of vibration on the stress distributions around the hole are investigated.
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Yoshimasa TAKAHASHI, Masaki TANAKA, Kenji HIGASHIDA, Hiroshi NOGUCHI
Article type: Article
Session ID: S0301-1-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The authors have previously observed a marked effect of hydrogen on cyclic slip behavior around a {110} fatigue crack tip in Fe-3.2wt.%Si alloy (Scripta Mater, 61(2009),145). In this study, a sustained load test is conducted to confirm the possible effect of hydrogen-assisted cracking (HAC). The result shows that no HAC exists along the {110} plane, demonstrating that the observed effect of hydrogen is limited solely to the cyclic slip mechanism. Crack growth process is then further discussed.
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Yutaka IINO, Hirotoshi MIYASHITA
Article type: Article
Session ID: S0301-1-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Notched compact tension specimens of SUS304 stainless steel (notch tip radius of 1mm and thickness of 6mm) were low cycle fatigued (stress ratio of -1) at RT in H_2 gas and in Pure air at 0.1Hz. Fatigue crack length of 2-3mm on the notch root surface was observed at number of cydes N=〜700 in Pure air and at N=〜200 in H_2. It is found that H_2 enhances the fatigue crack Initiation. The fatigue damage accumulation at midthickness of the specimens were observed by the recrystallization technique.
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S. KOIKEDA, S. ISHIHARA, M. SATO, T. GOSHIMA
Article type: Article
Session ID: S0301-1-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In the present study, fatigue crack propagation behavior and crack closure phenomenon of the aluminum alloy A6061 and carbon steel JIS S25C were investigated in detail. Differences in the crack closure behavior between them were discussed on the viewpoints of the compressive residual stress, the plasticity wake, and the roughness of the fracture surface.
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Satoru IZAWA
Article type: Article
Session ID: S0301-1-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The crack tip opening angle (CTOA) is a viable ductile fracture criterion and could be used for elastic-plastic, crack propagation analysis without the constraint of LEFM. This paper reports on our investigation to correlate ΔCTOA with the crack propagation rate, da/dN, in stainless steel (SUS 316), single edged notch bend (SENB) specimens. The SENB specimens were cyclically loaded at various constant load amplitudes with a load ratio, R〜0.01. ΔCTOA at the initial phase of fatigue crack extension was measured by moire interferometry and inferred from a ΔCTOA versus ΔCMOD master curve, which was constructed through CMOD and crack profile measurements, during the latter phase of fatigue crack extension. The fatigue data was then used to construct a da/dN versus ΔCTOA relation, similar to Paris' law of LEFM, in the presence of small to large crack tip deformation and net section yielding.
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Katsuyuki TOKIMASA, Yuya MIYAHARA, Shouhei ABE, Takao NISHIZAWA
Article type: Article
Session ID: S0301-2-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The PP (fast-fast) and CC (slow-slow) type combined push-pull and cyclic torsion tests have been conducted on thin-walled tubular specimens of SUS304 austenitic stainless steel at 623 K and 823 K in air under in-phase and 90 deg out-of-phase conditions, and the temperature and strain rate dependency of nonproportional loading effects on axial-torsional low cycle fatigue behaviors of SUS304 steel are examined. At 623K the reduction in life due to nonproportional loading is below a factor of 2 and the effects of strain rate on nonproportional test life is little, whereas, at 823 K, the reduction in life beyond a factor of 2 is observed in both in-phase and 90deg out-of phase straining CC tests and non-proportional loading effects are not observed in both PP and CC tests.
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Hirokazu FUKUNAGA, Yosihito KUROSHIMA
Article type: Article
Session ID: S0301-2-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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The general method is not always effective for the measurement of fatigue small crack growth properties by relation of accuracy and a device characteristic. Non-contact and the highly precise measurement are expected by the use of a magnetostriction effect to apply in this study. The small crack growth properties measurement by a magnetic field change with the magnetostriction effect that was one of a characteristic of magnetism of ferromagnetic substance was studied. Using a coil and a hall sensor, a magnetic field change with magnetostriction effect was detected, and the waveform changes of both outputs were inspected. The experiment result was revealed that the small crack affects a magnetic field change by a magnetostriction effect.
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Hiroyasu TATE, Izuru NISHIKAWA
Article type: Article
Session ID: S0301-2-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In order to reduce the weight of a vehicle, there are many demands of a usage of ultra high strength steel for an automobile body and its structure. However, the high-tensile steel has a definite weak point that its strength is extremely sensitive to the notch. Then, it aimed to clarify the sensitivity of the notch to fatigue strength. A conventional high-strength steel of 590MPa-class was selected for this study. The crack initiation mechanism of the notched member of high tensile strength steel was investigated through the measurement of a local strain at notch root using the Laser Speckle Strain/Displacement gage.
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Noriyasu OGUMA, Shunji YASUDA, Kazuaki SHIOZAWA, Tatsuo SAKAI
Article type: Article
Session ID: S0301-2-4
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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In order to clarify the appearing coaxing effect for interior inclusion induced fracture mode of bearing steel in rotating bending. Two step loading and step-wise increase loading tests were carried out using hour-glass shaped specimens in the ordinary room atmosphere. From the experimental results, interior inclusion induced fatigue life was almost equal to one of uniform loading tests. It seems that coaxing effect was not appeared against the interior inclusion induced fracture mode. Based on fracture mechanics, stress intensity factor range at the front of fine granular area (FGA) was almost same value to one of uniform loading test. But in the case of the increase loading in the beginning of fatigue, FGA size was smaller than others.
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Shigeaki So, Yoshihito Kuroshima
Article type: Article
Session ID: S0301-3-1
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Behavior of the S10C film under cyclic pure shear was different from the bulk. In this study, deformation behavior and crack propagation behavior of S10C film was discussed. As result, inhomogeneous deformation was hardly observed. The crack was propagated by combined of crack between pearlite grains.
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Kenichi SHIMIZU, Tashiyuki TORII, Kenji MARUYAMA
Article type: Article
Session ID: S0301-3-2
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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By using a new fatigue testing method in which the film was bonded to the cyclic loaded base plate with the inclined ellipsoidal through hole from the loading axis, the fatigue crack propagation behavior was discussed under mixed-mode conditions for a thin copper film. From the FEM analysis, stress on the film was uniform and principal stress direction was inclined from the loading axis of the base plate. As a result, the bent fatigue crack was initiated from the precrack and the crack propagation direction was almost perpendicular to the principal axis for an annealed copper film.
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Yoshikazu NAKAI, Chiaki Hiwa, Mitsuhiro MAKISAKA, Taiki KOYAMA
Article type: Article
Session ID: S0301-3-3
Published: September 12, 2009
Released on J-STAGE: August 01, 2017
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Ultra-fine grain α-brass (UFG brass) thin plates were made by repletion of rolling and heat-treatment. The thickness and the grain size of the plates were 0.1 mm and 10 μm for the plate with the initial thickness of 6 mm, and those were 0.120 mm and 1.5 μm for the initial plate thickness of 3 mm, respectively. The fatigue tests were conducting using an electro-hydraulic testing machine with the loading frequency of 30 Hz and the stress ratio of -1 at room temperature. The tensile strength and the 0.2% proof stress of the UFG brass was twice and five times higher than those of normal grain size a-brass (NG brass), respectively, while the elongation of the UFG brass was 1/3 of the NG brass. The fatigue strength of the UFG brass was scarcely higher than that of the NG brass. In the UFG brass, fatigue cracks usually initiated from pits those were formed during electro-chemical polishing process although they were initiated from slip bands for the NG brass. It indicates that the fatigue strength of the UFG brass is very sensitive to defects. Except for the fatigue strength of the UFG brass, the strengths linearly increased with increasing of the inverse of the square root of the grain size (Hall-Petch relationship). Although the tensile strengths were lower for thinner plates, the 0.2% proof stress and the fatigue strength for 10^7 cycles were almost independent of the thickness.
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