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Masato ENDOH, Tsutomu EZUMI
Article type: Article
Session ID: 827
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The polycarbonate (PC) is a polymeric material that excels in mechanical characteristics of an impact and weather resistance, etc. And is transparent that is. This material cases the phenomenon that is called a craze when the crack progresses from the property of low crystalline. There are mechanics a lot of .. unclarification yet.. fields though the study on the craze is done over many topics. Then, the craze was caused in PC in this study because of the tensile test, and it paid attention to a mechanics influence of the craze. The test piece shape used the CT test piece referring to JSME. Photodynamics and fracture mechanics of the craze was approached by using the method of caustics and the photoelasticity method for the evaluation method.
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Masakazu UCHINO, Masaaki KOGANEMARU, Tetsuya YAMAGUCHI, Satoru YONEYAM ...
Article type: Article
Session ID: 828
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A high-precise measurement method using a digital image correlation method combined with a fine adjustment stage is proposed for the purpose of the thermal deformation measurement of small parts like the electronic devises. An object mounted on the fine adjustment stage is made to move parallel to the in-plane of the object surface at the displacement magnitude of several tenth part of one pixel and the images of the object surface are taken by a CCD camera. Calibration curves of the horizontal or vertical displacement vs. transfer pixel of the every pixel point of image are made by using the obtained images. In the case of disregarding out-of-plane deformation, it is possible to carry out the high-precise in-plane displacement distribution measurement using the calibration curves. As an application, the deformation of a driving electronic package is measured using this system.
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Masaaki KOGANEMARU, Toru IKEDA, Eisuke MORI, Noriyuki MIYAZAKI, Masaka ...
Article type: Article
Session ID: 829
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The strain distribution measurement system using digital image correlation method was developed. And the accuracy of the measurement system was verified by the comparison with the strain gage and finite element method (FEM). The results of strain measurement using the system developed by present study were in good agreement with that measured using strain gage and analyzed using FEM. Then the thermal deformation of electronic package was measured using this system .The system using digital image correlation method can provide a reliable evaluation of mechanical reliability for electronic packages.
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Takahiro YUUKI, Tarou TOKUDA, Gounojyo KATAYAMA, Mituo KIDO
Article type: Article
Session ID: 830
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, The ID (indentation) method was used as a simple the measure of residual stress, and the influence of microstructure exerted on values obtained by the ID method was investigated for various Al_2O_3 ceramics. The residual stress ratio φ' of Al_2O_3 ceramics (the ratio of the value obtained by ID method and the setting stress value) changed with the microstructure (grain size and aspect ratio) of ceramics. When the setting stress value was tensile and the ID values were small, microstructure affects the values obtained by the ID method. The change of residual stress ratio φ' may be caused by the difference in indentation crack propagation behavior.
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Takanobu TAMIYA, Kenkichi SATO
Article type: Article
Session ID: 831
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The method of caustics, which is one of nondestructive optical measuring methods, is powerful technique to evaluate stress intensity factors (SIFs) and contact forces using caustic images formed from their stress concentrated areas. The shape and size of the caustic images depends on conditions of material, thickness, optical setup, etc. Caustic image simulation is applicable to evaluate the values of SIFs and contact forces, and also to set the experimental conditions before tests. To widely use the method and simulation of caustics, in this paper, a Java program has been developed for online simulations via web. The site opened is http://www.kouku-k.ac.jp/〜t-tamiya/index.html.
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Tetsuyuki HIROE, Kazuhito FUJIWARA, Yuuji NAKAO, Takenori MICHISHITA
Article type: Article
Session ID: 832
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Monotonic compressive loading, relaxation and cyclic straining tests were conducted under constant and time-varying strain rate conditions of 1.1×10^<-2>〜10^<-5> and 10〜40℃ for polyphenylen-ether (PPE), an amorphous polymer. The observed stress-strain responses were similar to those of other engineering plastics showing remarkable effects of the strain rates and temperature, but the strain-rate change tests revealed predominant overshoot phenomena in the stress transfer processes. The experimental results indicated that the concept of time-temperature equivalence is also applicable to PPE and the comparative investigation was carried out for five polymeric materials. The viscoplastic constitutive model based on overstress successfully reproduced the observed stress-strain responses including the overshoot phenomena using a newly proposed additional function which control the viscosity in the model. Finally, in the cyclic straining tests a unsymmetrical peculiar stress-strain curve appeared showing notable differences in tensile and compressive process.
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Satoshi KUBO, Hiroshi IIZUKA, Syuujun SHIKANO
Article type: Article
Session ID: 833
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Mechanical properties of the carbon material utilizing the natural structure of rice bran are investigated. The defatted rice bran is firstly mixed with a phenol resin, and then burned under nitrogen atmosphere to obtain porous carbon particles. In this study, the carbon particles are mixed with the synthesis polymer to get the composite materials. Especially, nylon and polyacetal, which are usually used for gear and so on, are investigated. The effects of particle diameter and weight percent of compounded particles on the tensile properties, fracture toughness and hygroscopic expansion were studied.
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Yoshihiro SHIBATA, Tomohiro WATANABE, Hiroshi IIZUKA, Syuujun SHIKANO
Article type: Article
Session ID: 834
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To make rice-bran carbon-materials, the defatted rice bran is mixed with a thermosetting phenol resin. The mixed materials are then carbonizing n nitrogen atmosphere to obtain porous carbon materials. The rice-bran carbon-materials have already been used practically as a linear motion sliding material. However, it is anticipated that the water-soluble inorganic compounds are produced during carbonizing. The compound may affect the mechanical strengths, when the rice-bran carbon-materials is used under aqueous environment. In this study, some improving methods for water resistance were discussed, measuring the compressive strength after long time water immersing
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Hiroshi IIZUKA, Tomohiro WATANABE, Yoshihiro SHIBATA, Syuujun SHIKANO
Article type: Article
Session ID: 835
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The porous carbon material utilizing the natural porous structure of rice bran has been produced and used as a linear motion slider. The rice-bran carbon-materials is produced mixing with a phenol resin and then carbonized under nitrogen gas atmosphere. Therefore, the components such as Mg, P, K in the rice bran are included in the rice-bran carbon-materials. Moreover, Na in phenol resin is also included in the rice-bran carbon-materials. These components may make a chemical compound with absorbency during the carbonizing. In this study, some improving methods to increase the mater resistance were discussed eliminating the absorbency compound and using phenol resin without Na.
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Hiroshi YOSHIDA, Takashi NAKAMURA, Hiroshi NAKAMURA, Toru NOGUCHI, Hit ...
Article type: Article
Session ID: 836
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To clarify the effect of direct fluorination on the mechanical properties, tensile tests of pristine and fluorinated PEEK were carried out. The surface states of these specimens during tensile tests were observed. It was found that: (1) The tensile strength and elongation at break of PEEK increased resulting from fluorination treatments. (2) Thinner depth of fluorination had better tensile properties under the same fluorinated temperature. (3) The changes of tensile properties were caused by the difference between the deformation of fluorinated layer and substrate layer. (4) The fracture process of fluorinated PEEK was affected not by fluorinated time but by fluorinated temperature.
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Shinji OCHI, Hitoshi TAKAGI
Article type: Article
Session ID: 837
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper presents the effect of heat-treatment on mechanical properties of natural fiber reinforced plastics. First, in order to investigate the effect of oxygen during heat-treatment on tensile strength of natural fibers, Manila hemp fibers were heat-treated in air and Ar. As a result, in the case of heat-treatment in Ar, the tensile strength of Manila hemp fibers was able to resist at higher temperature than that in air. Next, tensile strength of heat-treated Manila hemp fiber reinforced plastics was examined. The results showed that the tensile strength of Manila hemp fiber reinforced plastics also decreased at the same temperature as shown in the Manila hemp fibers heat-treated in air, although Manila hemp fibers embedded in resin. This temperature dependence is derived from the remained oxygen in lumens.
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Nobusuke HATTORI, Xuelan Yue, Shin-ichi NISHIDA
Article type: Article
Session ID: 838
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Aluminum-based metal matrix composites (Al MMCs) are attractive materials that can be used in various industrial fields. In this study, we investigate the preparation of a highly anisotropic stainless steel fibers (SSFs) reinforced aluminum composite by a hot extrusion process. The main results obtained in this test are as follows: (1) The microstructure and properties of the extruded composites are closely related to the hot extrusion conditions, such as temperature, pressure, extrusion speed, etc. (3) The porous microstructure and weak interface bonding lead to a low tensile strength.
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Masanobu TAKI, Shingo OKAMOTO, Tatsumi HAGIHARA, Nobuyuki FUYAMA, Tomo ...
Article type: Article
Session ID: 839
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The purpose of this research is to verify material qualities of fiber reinforced metal (FRM) that is used to reinforce pistons for engines of automobiles. The target of FRM in the present research is composed of metal mibers, Fe_<75>Cr_<20>Si_5 and matrix of aluminum alloy, AC8A. Tensile and compression tests were carried out on materials of 100%-AC8A and FRM under temperature conditions of 25℃, 150℃, 250℃, 300℃. Stresses and strains were measured by the tests. Young's moduli and Poisson's ratios were also found through the experimental results. Then Young's moduli were calculated using the proposed models and formulation.
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Yuki OMURA, Shingo OKAMOTO, Yoshikazu NISHIYAMA, Tomoo TADOKORO
Article type: Article
Session ID: 840
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The purpose of this research is to clear the effect of fiber-reinforced metal (FRM) on strength of pistons reinforced by FRM. First, the finite element model of a simplified piston of gasoline engines was constructed. Stress analyses were performed using the proposed model, in the case that combustion pressure was loaded to the piston made of aluminum alloy (AC8A). Stress analyses of the piston composed of aluminum alloy (AC8A) and FRM were also performed. The effect of FRM on strength of pistons was discussed using the results of stress analyses.
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Masahiro ISHIHARA, Satoshi HANAWA, Taiju SHIBATA
Article type: Article
Session ID: 841
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Oxidation-induced compressive strength damage of nuclear graphites was evaluated by the microstructure-related fracture model. Parameters used in the fracture model are grain size, pore size, pore size distribution etc. In the oxidation damage evaluation, growth of pores and change of fracture toughness due to the oxidation were considered in the model. Predicted results were compared with experimental data, and it was found that the prediction gives higher strength than the experimental data; this is thought to be the pore combination effect due to the oxidation.
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Tetsuya OHASHI, Shota KUMAGAI
Article type: Article
Session ID: 842
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Daisuke ECHIZENYA, Hiroo SAKAMOTO, Shiro TAKADA, Hiromichi AOKI, Hisas ...
Article type: Article
Session ID: 843
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Recently, photovoltaics market is growing over the world, and polycrystalline silicon cell make up over 70% of all photovoltaic devices. The cell and the solar module are lead during manufacturing process. Therefore it is important to improve the strength reliability of the cell for highly reliable solar systems In this paper, the bending strength of photovoltaic cell was quantitatively measured at each manufacturing process, and the surface condition of the cell was observed by SEM. It was found that the strength of the cell was improved by reaction with metal-past.
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[in Japanese], Bing Liu, [in Japanese], [in Japanese], [in Japanese], ...
Article type: Article
Session ID: 844
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Yoshifumi IWASAKI, Naoyuki KAKU, Yuji NAKASONE
Article type: Article
Session ID: 845
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The authors have shown that martensitic transformation can occur in the plastic wake regions around cracks in SUS304 austenitic stainless steel fatigued at room temperature in air. They have also discovered that there are strong correlations of crack length and volume fraction of transformed martensitie with the parameters of the leakage magnetic flux density distributions induced by the magnetization of the ferromagnetic martensitic phase around fatigue cracks. The electromagnetic characterization of the martensitic transformation is easy to make and can afford a macroscopic view of the martensitic phase in the length scale of the order of some millimeters. The electromagnetic method, however, cannot derive mesoscopic or smaller scale information about the martensitic transformation. The present study investigates the morphologies of the plasticity-induced martensite in different length scales. The authors used a ferrite scope and a flux gate sensor for macroscopic measurements. They also used an X-ray diffractometer having a focal size of 30μm for mesoscopic measurements of some ten micrometers and an electron back-scatter diffraction pattern (EBSP) analyzer for sub-micrometer measurements. The presentation will specify the difference in the morphologies of the martensite in the different length scales and show the correlations between the multiscale morphorogies.
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Masaru ZAKO, Tetsusei KURASHIKI, Futoshi KUBO
Article type: Article
Session ID: 846
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In recent years, it has been proposed that the multi-sale analyses are applied to structural design in order to reduce the development period. Though the various multi-scale analyses have been mainly applied to dynamics, they do not approach the subject in a thermal problem, which is the important analysis of structural design. Then, we have dealt with the formulation and the programming for the unsteady heat transfer problem by using mesh superposition method spotlighted in the stress analysis field. By comparison our proposed method with the traditional FEM, it has been verified that the developed program has good accuracy and the proposed method is usefulness to the structural design.
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Yasutomo UETSUJI, Mitsuteru HORIO, Kazuyoshi TSUCHIYA, Sei UEDA, Eiji ...
Article type: Article
Session ID: 847
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Masaru KARAIWA, Yasuhide SHINDO, Fumio NARITA
Article type: Article
Session ID: 848
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper presents the results of an experimental and numerical investigation in electric fracture behavior of composite PZT double torsion (DT) specimens. DT tests were conducted on a commercial piezoelectric ceramic bonded between two metals. Fracture loads under different electric fields were obtained from the experiment. Nonlinear three-dimensional finite element analysis was also employed to calculate the energy release rate for DT specimens based on the exact (permeable) and approximate (impermeable) crack models. The effects of applied electric field and polarization switching on the energy release rate are discussed, and the model predictions are compared with the results of the experiments.
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Seiichi KOBAYASHI, Kazuyuki SHIZAWA
Article type: Article
Session ID: 849
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to predict the plastic instability and the failure of polymer subsequent to the ductile large deformation, a macroscopic non-coaxial visco-plastic constitutive equation for polymers was derived, as well as a damage evolution equation expressing the generation and annihilation of craze was proposed in the previous report. In this report, the above system is coded into an explicit finite element method considering an inertial effect that is not considered for a numerical example in the previous report despite of including high strain rate dependence. Consequently, it is evaluated that this system is able to predict large deformation and failure of polymer under the impact deformation condition more realistically than the above previous static simulation.
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Shigetoshi ARAKI, Takako TOMITA, Akio SUGIMOTO
Article type: Article
Session ID: 850
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Void growth in a viscous resin is analyzed by using the equivalent inclusion method combined with the Mori-Tanaka theorem. In modeling, assume that the degree of the viscosity of the matrix resin changes with temperature according to the so-called W.L.F equation and the solid forming agent in the resin is sphere in its shape and it vaporizes to become a gas at the prescribed temperature. The pressure in the void formed by the forming agent is related with its volume by using the Boyle-Charles law. The volume of the void and the pressure in it are calculated to a cycle of heating and cooling and they are obtained as a function of the elapsed time in the cycle. The volume of the void increases with increase in the elapsed time and the pressure in the void decreases. The resultant volume of the forming resin is about 2 times to that of the original resin.
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Wakako ARAKI, Kentaro NEMOTO, Tadaharu ADACHI, Akihiko YAMAJI
Article type: Article
Session ID: 851
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, we discussed the fracture criterion for mixed mode of the epoxy resin at the room temperature. We conducted the three- and four-point bending tests to determine the fracture toughness under mixed mode loading and compared the experimental results with three theoretical fracture criteria: maximum hoop stress theory, minimum strain density theory, and maximum energy release theory. At lower mode mixity, namely closer to mode I, the fracture envelope and the crack initiation angle could be roughly predicted by the theoretical criteria. However, at higher mode mixity, especially at the vicinity of mode II, the fracture envelope followed neither theoretical nor empirical criteria, which could be due to the effect of thermo-viscoelastic relaxation phenomena, even when the crack initiation angle followed the maximum hoop stress criterion.
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Mitsugu TODO, Kazuo ARAKAWA, Hideto TSUJI
Article type: Article
Session ID: 852
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Biodegradable PLLA/PCL polymer blend was developed to improve the fracture toughness of brittle PLLA. Fracture tests of SENB specimens were performed to evaluate the fracture toughness values, K_<IC> and G_<IC>, of neat PLLA and PLLA/PCL. It was found that K_<IC> slightly decreases due to the blending, while G_<IC> dramatically improves. Scanning electron microscopy of fracture surface and polarizing optical microscopy of crack-growth behavior were carried out to investigate the fracture mechanism of PLLA/PCL. IT was found that the primary toughening mechanism in PLLA/PCL is the formation of craze-like damage initiated from voids generated from PCL spherulites.
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Yasutomo UETSUJI, Takehiro SHIMOYAMA, Masato NISHII, Masaru ZAKO
Article type: Article
Session ID: 853
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Tetsusei KURASHIKI, Masaru ZAKO, Satoru HIROSAWA, Makoto IMURA
Article type: Article
Session ID: 854
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Woven fabric composites with spread tow may induce better resin impregnation and mechanical properties than the conventional woven architectures. However, the mechanism of damage development of woven fabric composites with spread tow has not been investigated. To investigate the effect of spread tow on the damage development, we have developed the numerical simulation of the mechanical behavior based on damage mechanics. We have prepared two numerical models with a distribution of volume fraction in a strand, and an effect of the volume fraction in a strand on the damage development has been investigated. The numerical results indicate that the location of occurrence and the type of propagation of transverse cracks are quite different. Furthermore, the mechanical behaviors of woven fabric laminates with three layers with distributions of micro volume fractions in fiber bundles have also been analyzed. In this paper, the numerical results of the damage states are described.
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Tomo TAKEDA, Satoru TAAKNO, Yasuhide SHINDO, Fumio NARITA
Article type: Article
Session ID: 855
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper focuses on understanding the deformation and progressive failure behavior of glass/epoxy plain weave fabric-reinforced laminates subjected to uniaxial tension load at cryogenic temperatures. Cryogenic tensile tests were conducted on the woven-fabric laminates, and the damage development during loading was characterized by AE (acoustic emission) measurements. A finite element methodology for progressive failure analysis of woven-fabric composite panels was also developed, and applied to simulate "knee" behavior in the stress-strain responses and damage behavior in the tensile test specimens. The effect of strain concentrations due to the fabric architecture on the failure strain of the material was considered by incorporating the SVF (strain variation factor) from meso-scale analysis of a woven-fabric composite unit into the macro-scale analysis of the specimens. A comparison was made between the finite element predictions and the experimental data, and the agreement is good.
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Yasuhide SHINDO, Mayumi SUMIKAWA, Fumio NARITA, Kazuaki SANADA, Susumu ...
Article type: Article
Session ID: 856
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes an experimental and analytical study on fracture and damage behavior of GFRP woven laminates at cryogenic temperatures. CT (compact tension) tests were carried out at room temperature, liquid nitrogen temperature (77 K) and liquid helium temperature (4 K) to evaluate the critical values of the fracture mechanics parameters. During the CT tests, AE (acoustic emission) method was implemented. AE signals can identify the critical load at which gross failure occurs. A FEA (finite element analysis) was also done to calculate the fracture mechanics parameters. The failure criteria (Hoffman criterion and maximum strain criterion) or the damage variable based on the continuum damage mechanics was incorporated into the model to interpret the experimental measurements and to study the damage distributions within the specimen. Several methods of calculating J-integral are discussed.
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Tomohisa NAKAYAMA, Hirohisa KIMACHI, Hideki NIIMI, Keisuke TANAKA
Article type: Article
Session ID: 857
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Three-dimensional meso-mechanical analysis was conducted by the finite element method (FEM) in order to determine the elastic stress distribution around a crack tip in fiber-reinforced plastics (FRP). FRP plates were modeled as a typical 'one-fiber slice' model, represented by the fiber-resin model. The fibers were arranged in a square array with a fiber volume fraction of 0.60 Matrix crack is parallel to the fiber direction and is subjected to model I loading. The stress intensity factor, K_<lm>, and the average energy release rate was calculated for the above inhomogeneous FRP, and compared with those for a homogeneous FRP. For the long crack, the average energy release rate for the inhomogeneous FRP was equal to that obtained for the homogeneous FRP. For long crack, the matrix-stress distribution ahead of delamination can be divided into three regions: Region I, II and III (IIIa, IIIb) in the order of increasing distance from crack tip. The matrix-sterss in Region I had a singularity of 1/√r, but was smaller than that of the homogeneous FRP. Region IIIa has a singularity, too. But stress intensity factor of Region III was not equal to that of Region I. Region II was transitional region from Region I to IIIa.
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Kimihiro Nagashima, Takahiro Ohtsuka, Kiyosi Tanaka
Article type: Article
Session ID: 858
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The interlaminar shear strength tests of GFRP and ArFRP has been investigated by conventional short beam bend and double notched (DNS) tests. Although compression fracture took place near the jig in the short beam test on fabric GFRP, DNS specimens showed interlaminar shear fracture. DNS test seems to be applicable those FRP laminates.
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Go AOYAMA, Tadashi ASAMI, Masaaki MISUMI, Masafumi OHKUBO
Article type: Article
Session ID: 859
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Direct laminar shear test of C/C composite was conducted using a new developed test machine which can change compressive load on test specimens with four kinds of width. The relation between laminar shear strength and specimen width showed the independence of specimen width. The relation between laminar shear strength and compressive stress (0〜20MPa) showed nearly Quadratic equation behavior and original laminar shear strength in the condition of no compressive stress would be estimated.
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Kenichi Takemura, Hirotomo Shiibashi
Article type: Article
Session ID: 860
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Physical surface treatment was conducted for carbon fabric using sandpaper. Three kinds of sandpapers, No.1200, 800 and 600 were used. Static three point flexural test was conducted. The flexural strength of CFRP was improved more than 10%. The strength using No.1200 sandpaper is the highest which is improved about 16%. Elastic moduli were also improved. The modulus using No.600 sandpaper is the highest. Carbon fabric of CFRP was treated in only tensile or compressive sides in order to study the effect of physical surface treatment in detail. As a result, surface treatment to compressive side is more effective than that to tensile side for CFRP.
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Soon Chul KWON, Tadaharu ADACHI, Wakako ARAKI, Akihiko YAMAJI
Article type: Article
Session ID: 861
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The effects of particle size on fracture behavior of epoxy resin filled by spherical silica particles were studied. The epoxy resin was reinforced with silica particles having different mean sizes (1.56μm and 0.24μm) under different mixture ratios of small and large particles with the same volume fraction, 0.30. The three point bending test was conducted to measure fracture toughness. Consequently, the fracture toughness for above 70% of smaller particles was nearly two and half times higher than that of pure epoxy and two times for that of 100% larger particles, respectively.
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Yoshio ARAI, EIICHIRO TSUCHIDA, Rafiquzzaman MD, Seiya MURAYAMA
Article type: Article
Session ID: 862
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To contribute to a better understanding of the fracture mechanisms and stress distributions of aluminum cast alloy locally reinforced by SiC particle and Al_2O_3 whisker hybrid MMC a symmetrical four-point bending test was precisely analyzed experimentally and numerically. The four-point bending test was performed on straight beam specimens of rectangular cross section in the MTS machine, using special bending fixtures. The fracture mechanism and the fracture path ahs been investigated on the fracture surfaces. Crack initiation location and fracture surface morphologies have also been investigated. The stress distribution of SiC particle/Al_2O_3 whisker and homogeneous material joint have been calculated. Both the experimental results and the finite element simulation results show that the critical location for fracture is a region on MMC side near the interface.
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Akio SUGIMOTO, Hironori YAMASHITA, Shigetoshi ARAKI
Article type: Article
Session ID: 863
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Macroscopic loss factor and shear modulus of a sea-island type polymer-based composite is calculated by using the equivalent inclusion method combined with the Mori-Tanaka theorem. The influences of the loss factor and the shear modulus of the particle on the macroscopic loss factors and shear modulus of the composite are examined under the shear applied stress. Consequently, an aspect ratio of the particles influences on both of the macroscopic loss factor and the shear modulus of the composite. Moreover, it is found that an optimum range of shear modulus of the particles exists for the maximum value of the macroscopic loss factor of the composite in the case of any aspect ratio of the particles.
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Shintaro Kitakata, Toru Kuzumaki, Kazuki Enomoto, Naoto Ohtake, Yoshit ...
Article type: Article
Session ID: 864
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to understand the dynamic behavior of polymer matrix carbon nanotube (CNT) composites, modification and the destructive action of a CNT itself and CNT which exists in resin are examined with the dynamic action observation using the nano probe TEM (Transmission Electron Microscope). In has been considered that it is quite difficult to fracture CNT by bending deformation. However, it is revealed in this test that MWCNT is fractured by strong bending. It is also found that a crack arises by repeating buckling by compression. Moreover, it is observed in this test in the composite material, that with progress of a minute crack, MWCNTs fell out from matrix polymer in the nano-tensile test.
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Mario Kiuchi, Yoshitada Isono, Susumu Sugiyama, Takahiko Morita, Shinj ...
Article type: Article
Session ID: 901
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper reports new development of a tensile testing device driven by electrostatic actuator array for revealing mechanical and electrical properties of carbon nanowires used for nanomechanical sensors. The design concept of tensile testing device, are presented, which is composed of three elements; a carbon nanowire, electrostatic actuator array for applying uniaxial load to the nanowire and a cantilever for calibrating load and displacement. The fabrication process of the device using an SOI wafer is also established for high-accuracy arrangement of the nanowire on the testing device with the actuator array. The uniaxial tensile testing was demonstrated in order to obtain the force-displacement relation of the carbon nanowires.
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Takahiro NAMAZU, Yoshitada ISONO
Article type: Article
Session ID: 902
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper proposes a new high-cycle fatigue parameter for correlating fatigue lives of micro/nanoscale single crystal silicon (Si) structures under bending and tensile stressing. Fatigue tests of micro/nanoscale Si structures under bending/tensile stressing were conducted in order to reveal the influence of deformation mode on Si fatigue lives. Consequently, the authors enabled to propose a shear stress parameter for predicting fatigue lives of Si structures ranging from micro- to nanoscale, regardless of deformation mode and specimen size. The parameter can be used for reliable design of MEMS/NEMS components subjected to fluctuating stress.
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Hiroaki KITO, Takanori KIKUCHI, Yoshitada ISONO
Article type: Article
Session ID: 903
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We newly developed a full-reversed bending fatigue tester for evaluating low-cycle fatigue of MEMS materials. This paper focuses on design of the micro fatigue tester based on AFM technique, which can apply tension/compression loads to a microscale specimen of cantilever type, and establishment of the bending fatigue test procedure. The efficacy of the design and driven concept is demonstrated by applying a cyclic loading to the specimen and direct measurement of the applied load of the specimen using a bult-in laser reflection technique. This research succeeded in obtaining an elastic hysteresis loop of microscale specimen.
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Nagahisa OGASAWARA, Norimasa Chiba
Article type: Article
Session ID: 904
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A determination method for elastic-plastic material constants that obey the power-law hardening rule, from a couple of indentation tests, is proposed. Π function indicates the relation between reduced Young's modulus E, load curvature C, representative stress σ, and indenter apex angles φ. The function is determined by Π theory and two solutions for a sharp indenter penetration, the elastic solution and the rigid/perfectly plastic solution. With Π function and another function which relates representative strain ε, to indenter apex angle, two or more experiments lead points in plastic region respectively, and the stress-strain curve is identified.
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Takeshi AKAI, Tadahiro SHIBUTANI, Qiang YU, Masaki SHIRATORI
Article type: Article
Session ID: 905
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to study effect of load velocity on scratch test, scratch test were carried out with three different conditions on two scratch directions with Berkovich indenter. In the case that the edge of indenter was front, damage of interface was observed at 0.4mN〜0.6mN. In another, the critical load was nearly 1.2mN and was not connected with load velocity. In order to elucidate damage evolution of interface, we examined stress distribution on interface by FEM analysis. Stress concentrated on an edge of indenter. Therefore load value to be necessary for damage of interface is different in scratch direction.
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Hiroyuki HIRAKATA, Yoshitake YAMAMOTO, Shohei Matsumoto, Takayuki KITA ...
Article type: Article
Session ID: 906
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Analytical and experimental studies are carried out to evaluate interface strength between submicron structures and substrates on the basis of the fracture mechanics concept. Finite element analyses reveal that the stress intensity near the interface edge between a dot and substrate greatly increases with an increase of the aspect ratio of the dot. Delamination tests for submicron chromium (Cr) dots with different aspect ratios on a silicon dioxide (SiO_2) substrate are conducted by means of a modified AFM. The results show that the smaller load is required to separate the dots with higher aspect ratio from the substrate. This is desirable to evaluate the interface fracture toughness.
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Shoji KAMIYA, Shigenori SUZUKI, Takahiro YAMASHITA, Kiichiro YAMANOBE, ...
Article type: Article
Session ID: 907
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Thin films of barrier metals (TiN, TaN, etc.) are generally required underneath Cu line in order to obstruct Cu diffusion into adjacent dielectrics. Poor adhesion of the interface between Cu and barrier metal causes delamination and leads to deterioration of reliability. A quantitative evaluation of adhesion between Cu and barrier metals is urgently demanded from the reliability point of view. By applying a new technique developed recently by the authors, which can evaluate adhesion of thin film structure in terms of energy release rate, we investigated the interface toughness between the submicrometer Cu film and the barrier metal (TiN) in Cr/Cu/TiN/Si metallization
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Haruo ENDOH, Keita INOMATA, Katsuhiko MIYAMOTO, Tsutomu HOSHIMIYA
Article type: Article
Session ID: 908
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, the imaging of simulated surface defect using a photoacoustic (PA) microscope has been demonstrated. The surface tilt defect was the slit-type simulated defect, whose length was fixed to be about 4.0mm. The surface tilt defect with a width of 0.3 mm was introduced into the specimen by mechanical processing. The depth and angle values of the surface defects were 0.3 mm and 60, 70, 80 and 90 degrees in nominal value, respectively. By defining the "degree of asymmetry" as the ratio of the difference between two peaks of phase signal distribution to the height of their mean value from the background, the correlation coefficient between tilt angle and the degree of asymmetry showed the value of 0.997.
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Takamasa SUZUKI, Ysutaka MATSUBARA, Akihito MATSUMURO, Yutaka TAKAHASH ...
Article type: Article
Session ID: 909
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The prevention of residual stress of thin film syntheses is very important in processing engineering surfaces. In our previous paper, a method that controls the residual stress in crystalline films and the mechanism behind the control of the residual stress was clarified. However, the mechanical properties has not been clarified to date. In this experiment, TiN and Ti films were deposited on silicon substrate. The hardness and elastic modullus, frictional properties and fracture pattern of the films were measured by nanoindentation, pin-on-disk tester and in-situ surface observation system, respectively. The results of our experiment show hardness and elastic modulus decreased with the residual stress and film density. The adhesion strength showed a maximum value at near zero residual stress and the fracture pattern varied with adhesion strength. Moreover the fracture pattern of TiN films with residual stress over 0.5 GPa varied with the crystal orientation.
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Hirotaka TANABE, Yoshio MIYOSHI, Tohru TAKAMATSU, Shuichi SAGARA
Article type: Article
Session ID: 910
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A specimen which substrate was quenched after TiN coating was prepared, and the effects of heating time of the post quenching on the mechanical properties of TiN film were investigated. The residual stress and the hardness of TiN film were decreased with increasing the heating time. The adhesive strength and the substrate hardness were increased by the post quenching. With increasing the heating time, they once increased and then became constant from a heating time. In order to improve the adhesive strength and the substrate hardness with minimizing the decreases of the residual stress and TiN hardness, it is necessary to quench the steel substrate in the minimum heating time of which the adhesive strength and the substrate hardness are improved.
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Masahiro TAKANO, Akira HEYA, Toshikazu NIKI, Yasuto YONEZAWA, Toshihar ...
Article type: Article
Session ID: 911
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Silicon nitride (SiN_x) films were deposited on Si substrates at 80℃ by using a catalytic chemical vapor deposition (Cat-CVD) technique to investigate the optimal deposition condition. SiH_4 flow rate was varied from 6 to 18 sccm. It is shown that the stress, Young's modulus, fracture toughness and film composition strongly depend on SiH_4 flow rate. These changes of film properties are related to the gases desorption from growing surface. The amount of the gases desorption reaction depends on deposition rate, that is, the rate of the Si-H insertion reaction. The desorption of hydrogen and ammonia gases from growing surface causes the shrinkage of the film surface, which generates tensile stress. Also, SiN_x films with high hydrogen contents show low stress, low Young's modulus and high fracture toughness.
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Tomonori SASAKI, Kinuko FUJIMOTO, Ming YANG
Article type: Article
Session ID: 912
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A method of improving mechanical properties of Al thin films by low energy ion irradiation treatment after the deposition was proposed in this study. Young modulus and hardness of Al thin film were increased, spacing of lattice planes d was decreased and peak intensity of Al(111) was increased after the irradiation. The proposed treatment method is expected to improve surface mechanical properties of metal thin films deposited by various formation techniques.
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