STATISTICAL DISTRIBUTION PATTERNS IN MECHANICAL AND FATIGUE PROPERTIES OF METALLIC MATERIALS GENERAL PAPERS
Tatsuo SAKAI, Masaki NAKAJIMA, Keiro TOKAJI and Norihiko HASEGAWA
Review Paper (Vol.3 No.2)
STATISTICAL DISTRIBUTION PATTERNS IN MECHANICAL AND FATIGUE PROPERTIES OF METALLIC MATERIALS GENERAL PAPERS |
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Tatsuo SAKAI, Masaki NAKAJIMA, Keiro TOKAJI and Norihiko HASEGAWA |
63 |
General Papers (Vol.3 No.2)
SOLVENT MATERIALS FOR USE IN ELECTROLYTE SOLUTIONS OF RECHARGEABLE CELLS WITH LITHIUM METAL ANODES |
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Shin-ichi TOBISHIMA, Katsuya HAYASHI, Yasue NEMOTO and Jun-ichi YAMAKI |
75 |
EFFECTIVENESS OF CALCIUM SILICATE HYDRATE BRIQUETTE PRODUCED FROM FLY ASH AS A MICROORGANISM CARRIER |
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Yasushi HIRASHIMA, Tadashi TSUMURA, Toshihiro MORIGA, Toshifumi ASHIDA, Eiji KANEZAKI and Ichiro NAKABAYASHI |
81 |
SYNTHESES AND CHARACTERIZATION OF GRAPHITELIKE MATERIAL OF COMPOSITION BC6N2(H) |
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Masayuki KAWAGUCHI and Akinari SUGIYAMA |
88 |
PREPARATION AND PYROELECTRIC PROPERTIES OF ZIRCONIUM-MODIFIED LEAD LANTHANUM TITANATE CERAMICS AND THIN FILMS |
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Masayuki KOBUNE, Satoshi FUJII, Masanori HOSHIKA and Yasumori MAEDA |
94 |
AN EXPRESSION METHOD FOR QUANTITATIVE ANALYSIS OF REINFORCEMENT CONFIGURATION OF FIBER REINFORCED COMPOSITES |
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Shinji YAMADA, Zenichiro MAEKAWA, Seeram RAMAKRISHNA and Yoshihira OKANDA |
101 |
PREDICTION OF FAILURE IN ROCK MASSES BY ACOUSTIC EMISSION |
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Kazutoshi MICHIHIRO, Koji HATA, Toshio FUJIWARA and Hisaya YOSHIOKA |
106 |
EVALUATION OF BENDING STRENGTH AFFECTED BY SPECIMEN GEOMETRY IN SILICON NITRIDE |
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Toshihiko HOSHIDE, Hirokazu SANO and Hiroyuki HONDA |
112 |
SIMULATION OF MICROSTRUCTURAL EFFECTS ON CRACKING BEHAVIOUR IN BIAXIAL FATIGUE |
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Toshihiko HOSHIDE |
119 |
Vol.3 No.2 ABSTRACT
Tatsuo SAKAI, Masaki NAKAJIMA, Keiro TOKAJI and Norihiko HASEGAWA
Abstract:Many papers on the statistical aspect of materials strength have been collected and reviewed by The Research Group for Statistical Aspects of Materials Strength. A book of "Statistical Aspects of Materials Strength" was written by this group, and published in 1992. Based on the experimental data compiled in this book, distribution patterns of mechanical properties are systematically surveyed paying an attention to metallic materials. Thus one can obtain the fundamental knowledge for are liability design of mechanical structures such as the preferable distribution form and distribution parameters. Key Words:Statistical aspect, Mechanical properties, Fatigue strength, Distribution pattern, Metallic materials
SOLVENT MATERIALS FOR USE IN ELECTROLYTE SOLUTIONS OF RECHARGEABLE CELLS WITH LITHIUM METAL ANODES
Shin-ichi TOBISHIMA, Katsuya HAYASHI, Yasue NEMOTO and Jun-ichi YAMAKI
Abstract:A rechargeable cell with a lithium metal anode(lithium metal cell) is attractive because theoretically it has a high energy density. The problems with lithium metal cells are their short cycle life and poor safety resulting from their low cycling efficiency and the high chemical reactivity of lithium. One of the most important factors is the selection of the electrolyte materials. In this paper, We examine the influence of the composition of ternary mixed solvent electrolytes comprising ethylene carbonate(EC), Propylene carbonate(PC) and 2-methyltetrahydrofuran(2MeTHF) on the properties of AA-size Li/a- V205-P2O5 cells. The goals are to improve the cycle life of the cell while ensuring its safety and controlling its cost. The cell performance examined here includes cell capacity and charge-discharge cycle life. We also Carried out a heating abuse test at 1300 deg on the Li/a-V205-P2O5 cells. The best electrolyte composition was found to be 1.15M LiAsF6-E/PC/2MeTHF(15:70:15) from our overall results on cycle life, capacity, safety and cost. Key Words:Lithium, Rechargeable cell, Electrolyte solution, Amorphous vanadium oxide
EFFECTIVENESS OF CALCIUM SILICATE HYDRATE BRIQUETTE PRODUCED FROM FLY ASH AS A MICROORGANISM CARRIER
Yasushi HIRASHIMA, Tadashi TSUMURA, Toshihiro MORIGA, Toshifumi ASHIDA, Eiji KANEZAKI and Ichiro NAKABAYASHI
Abstract:Hydrothermal reaction of fly as with slaked lime Produces a porous briquette which is composed of amorphous calcium silicate, tobermorite and hydrogarnet. The molar ratio (calcium oxide)/(silicon dioxide), 0.3 in the synthesized briquette is essential for obtaining high ability for carrying microorganism. Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) indices in an artificial non-fecal drainage conducted with the porous briquette decrease more rapidly then those conducted with concrete blocks; decrease behavior in the use of the briquettes is similar to that in the use of activated charcoal. The briquette samples inoculated at low and medium temperature are effective in cleaning up water at low and medium temperature, respectively. X-ray photoelectron spectroscopy (XPS) spectra and scanning electron microscope (SEM) images of the briquette samples ensure that these samples are covered with biological membrane. These results indicate that the calcium silicate briquette produced from fly ash can be effectively used as a carrier of microorganism for the prevention of water pollution. Key Words:Fly ash, Hydrogen reaction, Water pollution prevention, Calcium silicate briquette, Environment
SYNTHESES AND CHARACTERIZATION OF GRAPHITELIKE MATERIAL OF COMPOSITION BC6N2(H)
Masayuki KAWAGUCHI and Akinari SUGIYAMA
Abstract:A new graphite-like layered material of composition BC6N2(H) is synthesized by the pyrolysis of (CH2CHCN)2 : BCl3 adduct, which is prepared by the interaction of acrylonitrile with boron trichloride at room temperature. X-ray diffraction and UV-Visible spectroscopic analysis suggest that the adduct has a cubic or quasi-cubic structure and is gradually polymerized at room temperature. A possible arrangement in a layer of BC6N2 has been considered on the basis of ESCA spectra and chemical interactions among the starting materials, being composed of a unit structure N-C-C-C-C-C-C-N-B. BC6N1.5(H) film prepared by CVD reaction (CH2CHCN:BCl3=2:1) has a conductivity of 5.31x104 S/m at room temperature and behaves as a semiconductor. The reduction of BC6N1.5(H) with Li+C10H8-/THF solution has yielded a lithium intercalated compound with a repeat distance of 0.87 mm. Key Words:Graphite-like layered material, B/C/N material, Adduct, Semiconductor, Conductivity, Host material, Intercalation
Masayuki KOBUNE, Satoshi FUJII, Masanori HOSHIKA and Yasumori MAEDA
Abstract:Zirconium-modified lead lanthanum titanate {(Pb0.925La0.075(ZryTi1-y)0.981O3+0.5 mass% MnO2, y=0-0.10,(PLZT)} ceramics and films were prepared by hot isostatic pressing and rf-magnetron sputtering , respectively. The electric properties of PLZT ceramics and films were investigated in detail. Assuming that the volume specific heat Cv of present ceramics and films is 3.2J/cm3 Ž, the PLZT films exhibited the highest figures of merit F.M. of l.4x10-10 Ccm/J for voltage responsivity and F.M.D of l.6x10-8 Ccm/J for specific detectivity of pyroelectric infrared sensors, Which were around 7.0 times and 2.8 time respectively, 1arger than those of present ceramics and PLZT(4/44/56) ceramics previously reported. The present films of y=0.04-0.10 are substantially expected as element materials for pyroelectric infrared sensors. Key Words:Ferroelectrics, Pyroelectric infrared sensor, Ceramics, Thin film, Hot isostatic pressing, Element material, Rf-magnetron sputtering method
Shinji YAMADA, Zenichiro MAEKAWA, Seeram RAMAKRISHNA and Yoshihira OKANDA
Abstract:Many kinds of reinforced configurations have been developed with the progress of fiber reinforced composites. Reinforcement configurations vary from one to three dimensions. Some methods are available in the literature for classifying various reinforcement configurations qualitatively. In this paper, efforts are made to develop a method for expressing various reinforcement configurations quantitatively. For this purpose two indices, structural index (D) and scatter index (C), are proposed. Furthermore the geometric dimension (k) and the degree of scatter (z ), are calculated. This method is applied successfully to several reinforcement configurations. Key Words:Reinforcement configuration, FRP, Structural index, Scattered index, Degree of scatter, Geometric dimension
PREDICTION OF FAILURE IN ROCK MASSES BY ACOUSTIC EMISSION
Kazutoshi MICHIHIRO, Koji HATA, Toshio FUJIWARA and Hisaya YOSHIOKA
Abstract:When constructing large caverns such as the one used for an underground powerhouse, it is of extreme importance to assume the stability of the cavern. As one of the techniques for stability monitoring, uniaxial compression tests were performed in various rocks and acoustic emission (AE) activity was measured. From the examinations of AE activity and the maximum amplitude of a single event, two types of AE occurrence patterns and three types of m-value variations were found. When predicting failure modes by means of AE, it is thought that total AE counts and the m-value can be useful for non-homogeneous rocks. On rocks of schistose or very homogeneous structures, the total AE counts provide useful information on failure prediction but the m-value dose not. Furthermore, from the results of spectral analysis of AE signal waves measured, it is found that the dominant frequency increases with increasing load. Key Words:Acoustic emission, m-value, Frequency analysis, Prediction of failure, Stability of cavern, Rock
EVALUATION OF BENDING STRENGTH AFFECTED BY SPECIMEN GEOMETRY IN SILICON NITRIDE
Toshihiko HOSHIDE, Hirokazu SANO and Hiroyuki HONDA
Abstract:Four-point bending tests of a gas pressured sintered silicon nitride were conducted using notched specimens with different notch shapes as well as smooth specimens of distinct sizes, and the effect of the specimen geometry on the bending strength was experimentally clarified. The mean Strength in smooth specimens could be almost correlated with the effective volume, though the mean strength in notched specimens shifted toward the lower strength side compared with the relation for smooth specimens. From observation of fracture surface, no unique correlation of the strength with the effective volume was suggested to be ascribed to a difference in flaw morphology between smooth and notched specimens. To discuss the efficiency of the effective volume, Monte Carlo simulation was also carried out by assuming the same distribution characteristics of cracks in a material. The simulated result revealed that the effect of the specimen geometry on the strength was explained by using the effective volume. The effective volume, however, was found to be in efficient because of a failure of the primitive assumption in the Weibull theory when the flaw density was extremely low in a material. Key Words:Ceramic strength, Size effect, Notched component, Effective volume, Four-point bending, Monte Carlo simulation, Statistical approach, Silicon nitride
SIMULATION OF MICROSTRUCTURAL EFFECTS ON CRACKING BEHAVIOUR IN BIAXIAL FATIGUE
Toshihiko HOSHIDE
Abstract:Some microstructural factors affecting cracking behaviour in biaxial fatigue were investigated in this work. A basic model proposed previously was developed in the analysis. The model consisted of an aggregate model of square elementary grain with double primary-conjugate slip system, and a competition model between the linkage dominant growth and the propagation of a single crack. The model was modified by introducing a clustering procedure to be appropriate for more general applications. Simulations based on the modified model were conducted n cracking behaviour Inconel 718 with a duplex grain structure and in SAE l045 with aligned large inclusions. Simulated results on cracking morphology and failure life were found to be in good agreement with experimental observations in the materials. Key Words:Biaxial fatigue, Microstructure, Modeling, Simulation, Cracking Behavior, Life evaluation