Transactions of the Japan Society of Mechanical Engineers Series A
Online ISSN : 1884-8338
Print ISSN : 0387-5008
Volume 55, Issue 520
Displaying 1-27 of 27 articles from this issue
  • Mitsuyuki KOBAYASHI, Hirokazu KITO, Yuichi KODAIRA
    1989 Volume 55 Issue 520 Pages 2377-2381
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    A low cycle bending fatigue test was carried out at 700°C with two types of strain wave forms, a symmetrical triangular-type and a one-side hold trapezoidal-type, using specimens with a weak grain boundary (WQ specimens) and specimens with a strong grain boundary (FA specimens) of an austenitic heat-resisting steel. In symmetrical triangular strain wave form, transgranular fatigue cracks were found to initiate and propagate to final fracture in both specimens, so that their fatigue lives were nearly equal irrespective of grain boundary strength. It was found in one-side hold trapezoidal-type strain wave form that WQ specimens fractured due to intergranular creep cracking from the side of tension holding, while FA specimens fractured due to transgranular fatigue cracking from the side of compression holding because of its strong grain boundary. This fatigue fracture process resulted in a much longer life in the FA specimens than that in the WQ specimens.
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  • Hironobu NISHITANI, Wataru FUJISAKI, Satoshi TANAKA, Hiroyuki TANAKA
    1989 Volume 55 Issue 520 Pages 2382-2387
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Recently, many high-performance sintered materials have been produced by hot isostatic pressing (HIP). In order to clarify the fatigue behavior of HIP-sintered SMF3035(HIP'ed SMF3035), rotating bending fatigue tests of plain and notched specimens were carried out and optical microscopic observations were made successively on the fatigue process by using the plastic replica method. The main results obtained are as follows. (1) In plain specimens, the crack initiates from an inclusion or a minute in-coherent structure. (2) The fatigue limit of plain specimens is determined by the limiting condition for propagation of a micro crack. (3) Crack initiation lives are smaller than 10% of the life for a fracture. (4) The value of the notch root radius at the branch point is nearly equal to 0.5 mm. This means that the present material is not as notch-sensitive as the steel having nearly the same carbon content.
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  • Yasuo NAGASE, Tamotsu NAKAMURA, Yoshiyuki NAKAMURA
    1989 Volume 55 Issue 520 Pages 2388-2396
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Fundamental characteristic of slip initiation and surface roughening phenomena in aluminum foil during the fatigue process are investigated under constant amplitude stressing. Applicability of the foil to the fatigue gauge that utilizes these phenomena to detect fatigue damage is discussed. It is found that the slip initiation phenomenon in aluminum foil is easily observed by an optical microscope and that the effects of temperature and cyclic speed on the slip initiation are quite small. Accordingly, aluminum foil can be used as the fatigue gauge that utilizes the slip initiation phenomenon. It is also found that evolution of surface roughness caused by the slip deformation is dependent on cyclic stress and the number of cycles. Therefore, this phenomenon also enables use of the foil as the fatigue gauge that makes use of surface roughness. Measuring accuracy of stress by this foil is about 5 MPa, and in-process measurements of cyclic strains or fatigue damage can be practicable provided that non-contact surface roughness measurement is adopted.
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  • Hiroshi HONGO, Jun KOMOTORI, Masao SHIMIZU
    1989 Volume 55 Issue 520 Pages 2397-2401
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    The effect of repeated annealing during the course of a fatigue test on a fatigue behavior was studied on two kinds of low-carbon steel having fine- and coarse-grained microstructures, paying special attention to the relationship between the fracture modes and fatigue life in the extremely low-cycle fatigue regime (Nf≤102). Results show that in a coarse-grained steel, (i) repeated annealing has the beneficial effect of repairing the damage inside the material; (ii) in this case, final fracture occurs in a surface fracture mode instead of internal fracture mode which normally appears in extremely low cycle fatigue regime. Such a change occurs after strain cycles obtained by the extrapolation from the fatigue life data for a surface fracture mode at low plastic strain range; and (iii) these findings can be clearly explained by the concept of "the competition of two failure limit lines which correspond to each fracture mode."
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  • Shinichi SUZUKI, Masahiro KAWACHI, Takurou NAKAJIMA
    1989 Volume 55 Issue 520 Pages 2402-2409
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    A holographic optical system developed which is used to photograph fast propagating crack tips in PMMA. The cracks are in the opening mode and propagate at a speed of several hundred m/s. At a point during crack propagation in a PMMA plate specimen, illumination light beams, emitted from a pulsed ruby laser, enter into the specimen through its side boundaries. Total reflection occurs at the specimen's surfaces as the light beams travel throughout the inside. When the beams reach the opened crack light is emitted, and is recorded on a holographic plate as the object light. The optical system is applicable only to cracks whose surfaces are "mirror" like and which propagates through transparent specimens. The optical system, however, makes it possible to measure in every photograph the crack opening displacement as a function of distance form the tip, even near the tip where craze appears.
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  • Toshihisa NISHIOKA, Hiroyuki KITTAKA, Hidetoshi UCHIYAMA, Tatsuyuki MU ...
    1989 Volume 55 Issue 520 Pages 2410-2415
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    The method of caustics (shadow spot method) has proven to be a powerful optical method to measure stress intensity factors in static and dynamic fracture-mechanics problems. In this paper, high-speed photographs of the caustic patterns for dynamically propagating cracks were taken by a laser caustic method which can be rapidly synchronized to the initiation of the brittle fracture event. The dynamic stress intensity factors were evaluated on the basis of a theory of caustics for mixed-mode fast-running cracks, which was developed by the present authors. Influences of the length of the double cantilever beam (DCB) specimen were thoroughly investigated. It was found that the crack arrest toughness values, KIA, in shorter specimens were larger than those in longer specimens.
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  • Dai-heng CHEN, Hironobu NISHITANI, Kazuya MORI
    1989 Volume 55 Issue 520 Pages 2416-2419
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    In order to clarify the response of a surface notch for plastic deformation, the influenced stress fields, i.e., the elastic stress distributions at the bottom of a notch due to a pair of point forces were investigated. According to the results, the response of a semielliptical notch for the plastic deformation is almost fully determined by the notch root radius ρ alone. Therefore, the severities of structures or specimens having a notch with a definite plastic deformation almost fully determined by the notch root radius ρ and the maximum elastic stress σe<max> alone.
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  • Fumio HAYAKAWA
    1989 Volume 55 Issue 520 Pages 2420-2422
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    Rice has reported a simplified method for estimating the J-integral for a deeply cracked bend bar. For a compact specimen, Merkle and Corten have shown a simplified method for estimating the J-integral which is taken into account the axial force. Ohji has also suggested a simplified method for estimating the J-integral for a deeply cracked bend bar. In this study, the relation between the Rice formula and the Ohji formula for a three-point bend specimen is analytically studied. J-estimation formula where is equivalent to Merkle-Corten formula for a compact specimen is also proposed. Results show that the Ohji formula for a three-point bend specimen is equal to the Rice formula. Based on the results, we can conclude that simplified methods for estimating the J-integral from the load and the displacement should be used when the strain hardening exponent is known.
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  • Tetsuo TERAMAE, Seiichi HAMADA
    1989 Volume 55 Issue 520 Pages 2423-2426
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    A practical numerical method has been proposed in order to analyze the damage of ceramics impacted by solid particles. This method mechanically represents the effect of damages such as crack and crush as stiffness reduction, and is implemented as new constitutive model in the general propose dynamic stress analysis program, DYMA3D. Several numerical results show that this approach well explains the experimental failure modes of ceramics impacted by small ball.
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  • Kazumi HIRANO, Hajime NAKAZAWA
    1989 Volume 55 Issue 520 Pages 2427-2433
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Fracture toughness tests were conducted on silicon carbide (SiC) whisker reinforced aluminum alloys in order to establish and standardize the testing method for determining a plane-strain fracture toughness KIC for whisker reinforced metals. Effects of whisker volume fraction and of whisker orientation on fracture toughness characteristics were studied on the basis of linear elastic fracture mechanics and fractography. Ultimate tensile strength σUTS greatly increased with increasing whisker volume fraction, but the increase in the whisker volume fraction resulted in a rapid decrease of KIC.
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  • Toshiro KOBAYASHI, Hiroshi MIYATA, Kenji KIKUSAWA, Takashi HIGASHIHARA
    1989 Volume 55 Issue 520 Pages 2434-2438
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    In the present study, fracture toughness of PMMA is evaluated based on the instrumented impact test and static three-point bending test. In the measurement of true fracture load in the instrumented impact test, a very difficult problem associated with a remarkable inertial loading effect is pointed out. However, it is shown that the inertial loading effect can be controlled by changing the period (τ) of vibration in specimen. It is also shown that the fracture toughness (KI) is affected by the loading rate (K^.). It is observed in the tested range of K^. (3.8 10-32.3 104MNm -3/2 S-1) that the changing tendency can be divided into three types. That is, KI increases monotonously at first, then decreases, and increases once again with increasing loading rate. Furthermore, it is observed that a feature of fracture morphology is the change from a stable fracture to an unstable one with increasing in K^..
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  • Noboru TANIMOTO, Kazutaka FUJITA, Takuo HAYASHI, Hidekazu FUKUOKA
    1989 Volume 55 Issue 520 Pages 2439-2444
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Numerical analysis is carried out based on characteristics under initial and boundary conditions of static pre tension and impulsive torsion. A constitutive equation of the Perzyna type is used and isotropic work-hardening is taken into account. Consequently, unloading behavior of the axial component is produced. Stress and strain distributions are changed considerably with the value of the material constant. The results of the calculation are also compared with that of the strain rate-independent theory. Both theories are compared with the experimental results.
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  • Gui-Rong LIU, Junji TANI, Tadashi OHYOSHI, Kazumi WATANABE
    1989 Volume 55 Issue 520 Pages 2445-2451
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Characteristics of surface wave propagation along the edge of semi-infinise plates (edge wave) are investigated by means of the semi-exact method proposed by the present authors. First, numerical results for the edge wave of isotropic semi-infinite plates are calculated and compared with those obtained by other published approximate theories and the FEM. The semi-exact method is found to be able to give the complete characteristics of symmetric and antisymmetric modes of the edge wave. An approximate relation between the velocity of energy propagation and Poisson's ratio is obtained for the first antisymmetric mode in high frequency. Next, frequency spectra are clarified for a unidirectional carbon/epoxy laminated semi-infinite plate and a hybrid composite laminated plate which consists of carbon/epoxy and glass/epoxy layers.
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  • Yuji TANABE, Ichiro MAEKAWA, Shinichi HANDA, Toshiaki HARA
    1989 Volume 55 Issue 520 Pages 2452-2457
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    The impulsive response of a semi-infinite viscoelastic circular rod to impact torsion is analysed by employing the correspondence relation between linear elasticity and linear viscoelasticity. Supposing that the 3-element standard linear solid model can be applied to the behavior of the rod in shear, we study the influence of the loading condition at the struck end, i.e., the radial distribution of shear stress and rise time of the applied torque on the stress or strain-time history. Analyses are done by the Laplace transformation and the numerical inversion of it by the use of the FFT algorithm. The fluctuations of stress or strain caused by waves of high orders are large when the impulsive torque concentrates near the center of the struck end. With increase of the viscosity of the rod and the rise time of the applied torque, these fluctuations become negligibly small and, as a result, only a 1-dimensional shear wave propagates in the rod.
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  • Tomoaki TSUJI, Naotake NODA, Toshikazu SHIBUYA, Takashi KOIZUMI
    1989 Volume 55 Issue 520 Pages 2458-2464
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    An impact torsion problem for a steppedbar composed of two semi-infinite bars bonded completely at each end is investigated. A stress singularity occurs at the corner of the bars. Therefore the stress analysis proceeds considering this stress singularity by making use of the series expansion technique, and the problems are reduced to an infinite set of systems of linear equations for each time step. A parameter which is similar to the stress intensity factor of a crack is defined. The values of this parameter, the displacement and the stresses are shown for various values of the mechanical properties of the bars.
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  • Hiroaki KATORI, Toru NISHIMURA
    1989 Volume 55 Issue 520 Pages 2465-2468
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    In the engineering beam theory shear deformation was neglected. No unified beam theory compensating the inconsistency caused by this has been yet proposed. On the basis of St. Venant's theory, the authors have studied so far on the coupled shearing and torsional deformation in the beams with arbitrary cross-section, and showed that these problems become the boundary value problems governed by Poisson's equation. In this study, these problems of coupled shearing and torsional deformation were analyzed by using the boundary element method in which the matrix of shear rigidity and torsional rigidity was determined. This matrix indicates the coupled shearing and torsional deflection. The shear center can be obtained determining the coordinate axes so as to eliminate the nondiagonal terms.
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  • Hiroaki KATORI, Toru NISHIMURA
    1989 Volume 55 Issue 520 Pages 2469-2474
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    One of the problems in beam theory is the incompletion of the theory for shear deformation. The authors previously proposed the method analyzing the problems of coupling shear and torsion in beams having arbitrary cross-sectional forms using St. Venant's theory by the finite element method, and the stiffness matrix for space framework elements, taking shear deformation into account, was determined. However, since the restraint and warping connection at beam ends cannot be taken into account in order to approximate these generalization and extension of the warping rigidity of Wagner's equation, in which the mode of warping is left as it is, and the magnitude is axially changed was attempted.
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  • Koichi ITO, Moriaki GOYA, Kiyoshi OHTSU
    1989 Volume 55 Issue 520 Pages 2475-2480
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    In the first report, a new expression of a constitutive law for elastic-plastic material was proposed using two transition parameters which are essential in describing the property of plastic materials. There parameters denotes the magnitude and direction of plastic strain increments. In this report, sufficient conditions of linear comparison solids are discussed in terms of those transition parameters. The characteristic of buckling of an elastic-plastic tube simultaneously subjected to axial load and internal pressure is then analyzed using Hill's bifurcation theory.
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  • Toshiaki HATA
    1989 Volume 55 Issue 520 Pages 2481-2487
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    This paper is concerned with a method for calculating the dynamic thermal stress distribution in a medium which undergoes thermoelastic and viscoplastic deformation due to sudden heating. It is a method for reducing the thermoelasto/viscoplastic problem to a sequence of thermoelastic problems with initial strains. The solution of this problem is determined by means of four displacement functions. Using the foregoeng method, the solution is derived for the dynamic thermoelasto/viscoplastic behavior of a thick-walled spherical shell suddenly subjected to a uniform temperature rise over its cross section. The numerical results show how the dynamic thermal stresses in spherical shell with viscoplastic properties change with time.
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  • Akio TAKIMOTO, Shinji YOSHINAKA, Yoshihiro NAKAMICHI
    1989 Volume 55 Issue 520 Pages 2488-2494
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    Equations expressing a tensile stress-strain relation of a dual phase material composed of a strong, brittle martensite and a weak, ductile austenite are proposed. This dual phase contains a constant volume of each phase and we call this the equation for a constant volume model (abbr. CVM). The experimental stress-strain data of the dual phase having various ratios of martensite to austenite are obtained and are analyzed by the equation using a computer with a multiregression program, and their best-fit flow curves are obtained. The above analysis of the co-operative deformation mechanism of two phases, which is balanced in stress and strain, shows that deformation starts with a bonding mechanism close to an equal strain chain and then gradually changes to one close to an equal stress chain as the plastic strain increases. The analysis of the plastic stress and strain concentrations in each phase is given in detail. These results are shown to agree excellently with the experimental data obtained from the X-ray residual stress measurements. The strain hardening exponent and the ultimate tensile strain of the dual phase decrease from the value of austenite to that of martensite as the volume of the latter increases.
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  • Masanori KURITA, Ikuo IHARA, Akira SAITO
    1989 Volume 55 Issue 520 Pages 2495-2502
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    The dependence of the x-ray elastic constants on the diffraction plate was investigated by using seven kinds of diffraction planes of α-alumina with chromium, cobalt and copper Kα radiations. The stress applied to a specimen with a bending device was measured by x-rays using the Gaussian curve method. No difference larger than the confidence intervals was observed in the measured x-ray elastic constants. The relative error σK/K of the stress constant K is proportional to K which is proportional to cotθ. Therefore, it is important to choose the diffraction angel 2θ as close to 180° as possible in order to determine the stress and the stress constant precisely. The (410) plane measured with cobalt Kα radiation is most suitable for stress determination because it not only has the highest diffraction angle of 168.4° but also the measured x-ray elastic constants almost agreed with both values calculated from Reuss and Voigt models for the elastic deformation of polycrystalline materials.
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  • Seiichiro KITAOKA, Kazuhiko OHSHIMA
    1989 Volume 55 Issue 520 Pages 2503-2509
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    The relation between the mean grain growth rate of grown grains in the electro-deposited copper foil by cyclic stress and the testing temperature was examined. The accuracy of the stress measurement method using mean grain growth rate and the propriety of the adaptation of its method to low temperatures were investigated. The grain growth process by cyclic stress is heat activated and the mean grain growth rate is expressed by an Ahrenius-type equation. The method proposed here is applicable to low temperature ranges where the conventional electroplating method cannot be applied.
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  • Masanori KURITA, Makoto SATO
    1989 Volume 55 Issue 520 Pages 2510-2515
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    A new method for the deformation analysis by the image processing using the Gaussian curve method is proposed in laser holographic interferometry. This method consists in determining the location and the broadness of a fringe pattern of a hologram by using the main axis and the standard deviation of a Gaussian function fitted to the intensity distribution curve of the fringe pattern. The location and the broadness of fringe patterns of a cantilever beam were determined by the Gaussian curve method. The deflection determined by this method agreed closely with the theoretical value. The deflection angle θ of a loaded cantilever beam decreases with the increasing standard deviation of the Gaussian function, called the Gaussian curve parameter (GCP) αα, and it is given by θ=5.11×10-5α-0.822
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  • Yukihiro OHTANI, Hideo KOGUCHI, Toshio YADA
    1989 Volume 55 Issue 520 Pages 2516-2520
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
    JOURNAL FREE ACCESS
    If some initial imperfections exist in the connection of structural members, a large strain concentration is induced by external loading. A large pressure vessel built by press bending and welding of steel plates occasionally creates initial distortion at the welded joint. The initial distortion often causes a reduction of the fatigue strength of the joint, owing to a considerable strain concentration. For rational quality assurance of the pressure vessels, a quantitative determination of relation between the initial distortion and the strain occurring at the joint is very important in all stages of the design, manufacture and maintenance of the pressure vessels. In the present paper, the authors theoretically discuss the influence of the shape of distortion on the strain concentration. The general formulae of strain calculation which are applicable to the arbitrary shape of distortion are obtained, and relation between the difference in the shape of distortion and the amount of strain concentration is graphically indicated.
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  • Nao-aki NODA, Hideo UMEKI, Fazil ERDOGAN
    1989 Volume 55 Issue 520 Pages 2521-2526
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    In this paper, the plane problem of two bonded elastic half planes containing a crack perpendicular to and going through the interface is considered. The problem is formulated as a system of singular integral equations by using the stress field induced by "the displacement discontinuity". In solving the equations, the hypersingular integral equation method (HIEM) and the body force method (BFM) are compared. The calculation shows that the HIEM, in which the unknown function is approximated by the product of the weight function and chebychev polynominals, gives rapidly converging numerical results in this analysis.
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  • Hideo KOGUCHI, Toshinori KAYA, Toshio YADA
    1989 Volume 55 Issue 520 Pages 2527-2532
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    The bonding of ceramics and metals is an effective method for applying ceramics to structural materials. In the previous paper, it was shown that high stress concentrations are induced only in the vicinity of the interface edge of the joint near the outer surface of a ceramic, and that the stress concentration can be reduced by modifying the shape of the ceramic. Using the thermoelastic-plastic finite element method, the authors investigate in the present paper how the thermal stress concentration and the shape of the plastic region in the metal are influenced by the size of both materials. It is found that the values of the stress concentration in the axial direction and the shape of the plastic region in the metal are changed by modifying the size of both materials, and that the plastic region in the metal develops from the bonding interface.
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  • Yasuyuki SEGUCHI, Masao TANAKA, Takunori YAMAGUCHI
    1989 Volume 55 Issue 520 Pages 2533-2537
    Published: December 25, 1989
    Released on J-STAGE: February 21, 2008
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    The preliminary design of a framework structure is studied in terms of a knowledge-based assistant. The aim is toward an artificial assistant but not a system of automatic design, although the generative parts essential to the latter are maintained. Besides the capability to generate a specific design candidate, some basic features are installed in such an assistant; e.g. presenting multiple candidates that should be considered by a designer, providing some pieces of information useful for evaluation, and backtracking the design process at any time. A quantitative analysis based on default values for detailed design items is also useful for the evaluation of the candidates presented by the assistant. An experimental assistant system for the layout of a truss bridge is developed by taking into account the above-mentioned features based on the conventional design knowledge, and some case studies are demonstrated.
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