JSME International Journal Series A Solid Mechanics and Material Engineering
Online ISSN : 1347-5363
Print ISSN : 1344-7912
ISSN-L : 1344-7912
Volume 41 , Issue 2
Showing 1-18 articles out of 18 articles from the selected issue
  • Nobutada OHNO
    1998 Volume 41 Issue 2 Pages 167-177
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The present paper deals with state of the art in creep rupture analysis of unidirectional composites reinforced with long brittle fibers. Experiments, numerical simulations and analytical models related with the creep rupture analysis are treated mainly on metal matrix composites, which can be mathematically modeled more easily because of the assumption of global load sharing. It is described that matrix creep and statistical fiber fracture play important roles in understanding and predicting the creep rupture of such composites appropriately. It is emphasized from the mechanics point of view that two kinds of stress relaxation, i.e., relaxation of matrix normal stress and that of interfacial shear stress around fiber breaks, are the key to the creep rupture in short and long terms, respectively.
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  • Naotake NODA, Shinji NAKAI, Tomoaki TSUJI
    1998 Volume 41 Issue 2 Pages 178-184
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Functionally graded materials(FGMs) have been developed as ultrahigh temperature resistant materials for aircraft, space vehicles and other engineering applications. Most FGMs are particle-reinforced FGMs and these composition vary on a position. In the study of FGMs, the material properties due to macroscopic combination-law have been adopted. However in order to obtain more correct thermal stresses in the FGMs, it is necessary to analyze thermal stresses by use of the microscopic combination-law. Using the constitutive equations for the particle-reinforced composites, the stress-strain relations of particle-reinforced composites taking into account the effect of the manufacturing process, and the stress distribution in an FGM plate subjected to heating are discussed. The number of damaged particles and the possibility of crack generation taking into account the manufacturing process are also discussed.
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  • Toshimichi FUKUOKA, Tomohiro TAKAKI
    1998 Volume 41 Issue 2 Pages 185-191
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In the tightening process of a bolted joint using torque control, the effects of friction on axial tension of bolt and torque is an issue of great interest. In this study, the mechanical behaviors of a bolted joint during tightening, such as variations of axial tension and torque, are investigated both experimentally and numerically. Hence, friction coefficients on pressure flank of screw thread and the nut loaded surface are estimated by measuring the total torque applied to nut, axial tension and thread friction torque, and compared with variations of axial tension and torque. The validity of the finite element approach proposed here for evaluating changes in torque and axial tension is ascertained by comparing the numerical results to the experimental ones. It is also shown that the size of grip length influences, to some extent, the reduction rates of torque and axial tension.
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  • Seiichi YAMAJI
    1998 Volume 41 Issue 2 Pages 192-198
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A boundary element analysis system using p-version, which is an adaptive mesh refinement scheme, was developed. Generally, elements in the p-version finite element method(FEM) are formulated using the interpolate function based on the hierarchical polynomial, and the amplitude of high-order function is chosen as the unknown value. In this study, a high-order boundary element that possesses unknown displacements of the collocation point was developed. This element makes it possible to apply the p-version even to contact problems that there are various contact conditions within the element. An effective and efficient error evaluation method suited to the p-version based on the stress mode amplitude, in which the stress distribution is converted into the stress mode amplitude using the hierarchical interpolate function, is proposed. The system was applied to both basic and practical examples, and its application to actual equipment demonstrated its usefulness.
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  • Kaishin LIU, Suming XIE, Shinji TANIMURA
    1998 Volume 41 Issue 2 Pages 199-203
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this paper, a numerical scheme based on the method of numerical integration along bicharacteristics is developed for the numerical analysis of two-dimensional torsional stress wave propagation in layered transversely isotropic cylinders. The distributions of the dynamic shear stresses in the vicinity of the junction of a layered transversely isotropic cylinder are studied. Moreover, the stability and limitations of the present scheme are investigated.
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  • Wen-Fung PAN, Wu-Jiunn CHIANG
    1998 Volume 41 Issue 2 Pages 204-210
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    This study replaces the material parameter in the scaling function of the intrinsic time scale, as proposed by Pan et al.(1) with an exponential function. Thus, the endochronic theory can be used to simulate the creep behavior of material under multiaxial loading. Experimental creep-test data obtained by Ohashi et al.(2) on type 304 stainless steel at 650°C under nonproportional repeated loading are used for evaluating the theoretical simulation. In addition, a simple endochronic creep model proposed by Lee(3) and four creep models employed by Kawai(4) are also included herein. It is shown that the experimental results are aptly described by the novel theoretical approach demonstrated from a comparison with the theoretical prediction from models employed by Lee(3) and Kawai(4).
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  • Akira KURUMADA, Tatsuo OKU, Kiyohiro KAWAMATA, Osamu MOTOJIMA, Nobuaki ...
    1998 Volume 41 Issue 2 Pages 211-217
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The purpose of this study is to contribute to the development and safety design of plasma facing components for fusion reactor devices. We evaluated the thermal shock resistance and the thermal shock fracture toughness of a joining material which was used to join a carbon fiber reinforced carbon composite(C/C composite) to oxygen-free copper. We also examined the microstructures of the joining layers using a scanning electron microscope before and after thermal shock tests. The joining material did not fracture during the thermal shock tests. However, thermal cracks and delamination cracks were observed in the joining layers.
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  • Ken-ichi KOBAYASHI, Haruyuki IMADA, Tamotsu MAJIMA
    1998 Volume 41 Issue 2 Pages 218-224
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Several creep damage tests of pure aluminum were carried out using circumferentially notched bars, which can easily produce multiaxial state of stress near net section. The surface of notch root and longitudinal section with central axis were inspected to observe the growth of creep voids and cracks by means of scanning electron microscopy and optical microscopy. Experimental results show that the maximum length of the largest creep void/crack on the notch surface can be expressed as an exponential function of lifetime ratio. This will help to predict residual lifetime of components with these notches. However, a great care is required not to miss the maximum creep defect, because only a part of creep voids and cracks appears on the surface of notch root and most of the creep defects lie inside the notch root.
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  • Taketoshi NOJIMA, Takayuki KUSAKA
    1998 Volume 41 Issue 2 Pages 225-230
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Fracture behaviours in mode I delamination tests of CFRP(T300/2500)were studied at cross-head velocity V=0.005∼200 mm/min. In low velocity region, serrations due to repeated unstable fracture appear on load P-displacement δ curve, and they become conspicuous as V becomes smaller. The crack resistance force R evaluated by using the peak values of the serrated P-δ relation becomes larger with the decrease of V;the rate dependence of R is negative. On the other hand, at velocities higher than the critical one(VC), there is nothing but fluctuations on P-δ relations. Although the rate dependence of R is extremely small, it is a positive value. Relaxation tests were also performed for specimens deformed at lower and higher velocities than VC;at high velocity, load P decreases with time, while at low velocity, the load remains constant during relaxation test. The rate dependence and fracture behaviours have been discussed by using a model which takes the crack tip blunting effect into account.
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  • Panagiotis FRANTZIS
    1998 Volume 41 Issue 2 Pages 231-242
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Epoxy resins are widely employed as adhesives and are being increasingly used in engineering industries. The prediction of the strength of adhesively bonded components is vitally important and different approaches and methods are being used to investigate the fracture behaviour and predict the durability of adhesive joints when they are exposed to hostile environments. Typical accelerated ageing tests used in industrial laboratories employ adhesive joints immersed in water and subjected to static tensile stresses, where the fracture stress and the time to failure are measured in order to generate basic design data. However, in this type of work, fracture mechanics is a more useful technique. The present work is therefore concerned with the design and development of new accelerated ageing test equipment employing double-torsion adhesive joints exposed to moisture and static stresses. This allowed the determination of the fracture energy versus crack velocity and incubation time relations.
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  • Kazuhiro MORINO, Hironobu NISITANI, Futoshi NISHIMURA
    1998 Volume 41 Issue 2 Pages 243-251
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this paper, an effective and convenient method for estimation of low cycle fatigue life based on the small-crack growth law was proposed, and the factors that control fatigue life were clarified. The main results obtained are as follows:(1)Low cycle fatigue life is controlled by three factors:crack initiation length, crack propagation limit length and relative crack growth rate. (2)Fracture in pearlitic spheroidal graphite cast iron(PDI)starts from a microshrinkage that exists on the neighboring surface in the case of a cylindrical specimen;thus, the crack initiation length in PDI is larger than that in its matrix material(0.85%carbon steel;JIS SK5). (3)Preexisting cracks originating from defects shorten the crack propagation limit length. (4)The relative crack growth rate is accelerated by the increase in crack opening displacement range near the crack tip.
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  • Kohji MINOSHIMA, Shigeyoshi SATOH, Kenjiro KOMAI
    1998 Volume 41 Issue 2 Pages 252-259
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    We describe an investigation on the fatigue fracture behavior of an SiC whisker reinforced A6061 aluminum alloy fabricated by a squeeze casting process under combined tension/torsion loading at room temperature. Attention was focused on in-phase and out-of-phase tension/torsion loading. The tests were conducted under a load-controlled condition keeping a constant value of the combined stress ratio, α=τmaxmax. Irrespective of loading condition, the mechanical properties of the composite including fatigue strength were superior to those of an unreinforced A6061 alloy, not only under uniaxial loading, but also under combined in-phase and out-of-phase tension/torsion loading. In the case of the unreinforced matrix material, the fatigue strength under out-of-phase combined loading was smaller than that under in-phase loading. However, for the composite, the fatigue strength under out-of-phase combined loading was higher than that under in-phase combined loading. The crack initiation and propagation behavior was closely examined using a surface replication technique, and the fracture mechanisms under in-phase and out-of-phase combined loading were discussed.
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  • Minoru MUKAI, Takashi KAWAKAMI, Kuniaki TAKAHASHI, Kikuo KISHIMOTO, To ...
    1998 Volume 41 Issue 2 Pages 260-266
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Fatigue life estimation of solder bumps is one of the most critical technologies for the development of ball grid array packages(BGA). In this study, strain singularity was examined based on the analytical results for the primary solder bump model. The result suggested that it was desirable to employ the equivalent creep strain range occurring at a distance of 0.05 mm from the singularity point. The fatigue life estimation of the actual solder bumps was performed based on this consideration. The estimation result for the crack initiation was in good agreement with the experimental results. A simple estimation of the crack propagation based on the linear damage law was also proposed for convenience' sake. The trend of the simple estimation results corresponded well with the experimental results of crack propagation. Therefore, the fatigue life estimation of solder bumps based on the present method is satisfactory for engineering purposes.
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  • Hisao FUKUNAGA, Hideki SEKINE, Yasushi MATSUNO
    1998 Volume 41 Issue 2 Pages 267-273
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The present paper deals with a deformation control of a laminated composite plate with distributed piezoelectric actuators under static loading. Deflection of the plate is controlled using actuators bonded symmetrically to the plate surfaces. Static response of the plate with distributed actuators is calculated by a two-dimensional finite element analysis incorporating the stiffness effect of actuators. In order to minimize the deflection of the plate at the specified locations, the optimal voltage applied to the actuators is obtained by the least squares method. The effect of the geometry and the number of actuators on the deformation control is discussed through several numerical examples for cantilevered laminated plates.
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  • Kenji GOMI, Yasushi NIITSU
    1998 Volume 41 Issue 2 Pages 274-279
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    We developed an optical birefringence measurement method that uses a photoelastic modulator and a polarized laser. A He-Ne infrared laser was utilized as the light source for measuring the birefringence in gallium arsenide wafers. In this paper we will explain the theory behind this method and the process of measuring the stress in GaAs wafers. The magnitude of the principal stress difference as well as the directions of the principal stresses were obtained simultaneously and quantitatively by using equipment developed for this study. The optical birefringences of stressed GaAs specimens were measured. From the experimental results, it was found that the photoelastic constant depended upon the crystalline orientations. Furthermore, the birefringence direction did not always coincide with the principal stress direction. The relationship between the principal strain difference and the retardation was obtained by the stress-strain analysis of a single GaAs crystal. That relationship was almost independent of the crystalline orientations and the birefringence direction was almost equal to the principal strain direction.
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  • Keisuke TANAKA, Yoshiaki AKINIWA
    1998 Volume 41 Issue 2 Pages 280-286
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The diffraction elastic constants are necessary for stress measurements of multi-phase materials by X-ray and neutron diffraction methods. The secondary phases can influence the diffraction elastic constants as well as the mechanical elastic constants. The micromechanical analysis based on Eshelby's inclusion mechanics was conducted to obtain the mean stress in diffracting crystalline phases in multi-phase composites under the applied stress. The diffraction elastic constants of multi-phase materials are determining as a function of the mechanical elastic constants. The method was applied to predict the effect of secondary phase on the diffraction elastic constants of sintered alumina with different purities. The predicted values for alumina 146 and 2.1.10 diffractions agree very well with the experimental results obtained by the X-ray diffraction method.
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  • Keisuke TANAKA, Yoshiaki AKINIWA
    1998 Volume 41 Issue 2 Pages 287-289
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A new method of X-ray measurements of tri-axial residual stresses was proposed for hexagonal polycrystals with the[001]fiber texture. The relation between X-ray strain and sin2 ψ is linear for the cases of the fiber axis perpendicular or parallel to the specimen surface, provided that there is no shear stress acting on the specimen surface. The in-plane stresses, σ11 σ22 and σ12 and the normal stress perpendicular to the specimen surface, σ33 can be determined from the slope and the intercept of the linear regression line for the relation between X-ray strain and sin2 ψ obtained for three different directions.
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  • Keisuke TANAKA, Yoshiaki AKINIWA, Kaoru INOUE, Hiroyuki OHTA
    1998 Volume 41 Issue 2 Pages 290-296
    Published: April 15, 1998
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A new method of X-ray stress measurement was proposed for measuring the triaxial residual stress in thin films of cubic polycrystals having the[111]fiber texture with the fiber axis perpendicular to the film surface. The elastic deformation of poly crystals is assumed to follow Reuss or Voigt models. The method was applied to measure the residual stress in patterned aluminum(Al) thin films sputtered on silicon single crystal wafers. The strain was measured from Al 222 and 311 diffractions obtained by Cr-Kα radiation. The values of in-plane residual stresses σ11 σ22 and σ12 and out-of-plane normal residual stress, σ33 were determined from the measured strains by using the fundamental formulae derived on the basis of Reuss and Voigt models. The residual stress in unpatterned thin films was equi-biaxial tension and the magnitude did not vary with the film thickness. The residual stress in patterned thin films was tensile, and its magnitude decreased with increasing ratio of line thickness to line width. The residual stress perpendicular to the line pattern was smaller than the parallel stress.
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