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Sumio MURAKAMI
1985 Volume 51 Issue 467 Pages
1651-1659
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Takeshi OGAWA, Hideo KOBAYASHI, Takamichi KOIDE, Hajime NAKAZAWA, Eiji ...
1985 Volume 51 Issue 467 Pages
1660-1667
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Hironobu NISITANI, Norio KAWAGOISHI
1985 Volume 51 Issue 467 Pages
1668-1676
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Masahiro JONO, Jiho SONG, Yoshinori YAMA, Norio NISHIGAICHI, Masahiko ...
1985 Volume 51 Issue 467 Pages
1677-1686
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Hideo KOGUCHI, Yukio HORI
1985 Volume 51 Issue 467 Pages
1687-1694
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Hideo KOGUCHI, Yukio HORI
1985 Volume 51 Issue 467 Pages
1695-1701
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Tamotsu TAMAKI, Eisaku UMEZAKI, Masatsune YAMAGATA, Shun-ichi INOUE, K ...
1985 Volume 51 Issue 467 Pages
1702-1709
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Takashi IMURA, Osamu DOI
1985 Volume 51 Issue 467 Pages
1710-1716
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Hironobu NISITANI, Hiroshi NOGUCHI
1985 Volume 51 Issue 467 Pages
1717-1725
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Fumio NAGAI, Satoshi SATO
1985 Volume 51 Issue 467 Pages
1726-1733
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Shiro KUBO, Kiyotsugu OHJI
1985 Volume 51 Issue 467 Pages
1734-1740
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Masataka TOKUDA, Hideyuki KATO
1985 Volume 51 Issue 467 Pages
1741-1749
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Yasuyoshi FUKUI, Kenji NAKANISHI, Shun-ichi OKAMURA
1985 Volume 51 Issue 467 Pages
1750-1756
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Masahiro ICHIKAWA, Satoshi AKITA, Satoshi KISHIMOTO
1985 Volume 51 Issue 467 Pages
1757-1763
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The statisitical nature of the cumulative cycle ratio, D=Σn
i/N^^∼
i, of a chopped-strand-mat glass fiber reinforced plastic under random and program loading has been studied experimentally, where N^^∼
i was the median life at the stress amplitudeσ
i as obtained from the S-N curve. In similar to the fatigue life N in constant amplitude tests, D followed a log-normal distribution approximately. The variance of log D in the random and the program load tests was approximately the same as that of log N/N^^∼
i in the constant amplitude tests. This implies that the coefficient of variation of D is approximately equal to that of N. The mean of log D was not equal to zero, hence Miner's rule did not hold statistically. A phenomenological explanation of the tests results was attempted.
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Seiichiro KITAOKA, Jian-qiao CHEN, Masaichiro SEIKA
1985 Volume 51 Issue 467 Pages
1764-1771
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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In order to investigate the condition of the threshold of micro fatigue crack propagation under mixed mode, plane bending and cyclic torsion tests, and the various combinations of them are carried out under the condition of the stress ratio R=-1 by using the annealed cracked specimens made of carbon steel. Based on the assumption that a crack begins to propagate when the circumferential principal stress reaches a critical value peculiar value peculiar to the material, the stress condition at the threshold of crack propagation under mixed mode can be explained by applying the test results of plane bending and cyclic torsion.
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Ryoji YUUKI, Toshiaki OHIRA, Haruaki NAKATSUKASA, Won YI
1985 Volume 51 Issue 467 Pages
1772-1779
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The stress intensity factors for various spot welded joints such as tensile-shear, cross- tension, T type tension and bending specimens, are analysed by finite element method. The fatigue strength and the fatigue crack pathes for these specimens can be well characterized by the stress intesity factors analysed and a mixed mode fracture criterion. It is found that fracture mechanics is a powerfull approach to evaluate the fatigue strength for various spot welded joint specimens with different loading systems, plate thicknesses and nugget diameters.
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Tsuneshichi TANAKA, Tatsuo SAKAI, Kenji OKADA
1985 Volume 51 Issue 467 Pages
1780-1788
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Rotating bending fatigue tests were carried out on S50C steel specimens having four drilled holes with random distance at the critical section to investigate statistically the propagation behavior of surface cracks and their coalescence leading to the failure of specimen. The important findings in the present study are summarized as follows. It was observed that the first crack coalescence was encountered between adjacent holes with the minimum distance or second small distance. There was little difference between the number of cycles to crack coalescence and that to failure. The distribution of the number of cycles to crack coalescence has been theoretically derived on the basis of crack coalescence probability as a result of theoretical analysis with the assumption of the first crack coalescence occurring between adjacent two holes of the minimum distance or second small distance. The theoretical distribution thus derived shows a good agreement with that of experimental trends.
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Toshiaki HATA
1985 Volume 51 Issue 467 Pages
1789-1794
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The principal aim of this paper is to investigate the thermoelastic problems in a nonhomogeneous semi-infinite elastic solid whose shear modulus increases with its depth according to relation μ
0Z
α(μ
0 and α are constants). The solution of the problem is determined by using two kinds of displacement functions. In this paper, the case αν=1-2ν, ν=Poisson's ratio, corresponding to an alloy made in a process of binary diffusion coupled with a large concentration gradient is discussed in detail. Numerical results are presented for the thermal stress distribution in a nonhomogeneous semi-infinite elastic solid with surface radiation.
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Hisao HASEGAWA, Satoshi TOKOYODA
1985 Volume 51 Issue 467 Pages
1796-1802
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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This paper concernes with the stress concentration problems of an elastic strip with two pairs of semicircular notches under tension. The method of solution is based upon an application of Green's functions for body force problems of a strip. That is, a principle of the method of solution is to distribute body forces in the interior of a strip with no notches and to determine the intensities of the body forces distributed so as to satisfy the boundary conditions of the notches. Numerical results are obtained systematically for various kinds of notch sizes. An investigation is made for interference effects of stress concentrations due to two pairs of notches and the influences of radii of notches and distances between two pairs of notches on the stress concentration factors.
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Hironobu NISITANI, Nao-aki NODA, Izumi FUKASAKO, Shoji HARADA
1985 Volume 51 Issue 467 Pages
1804-1810
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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This paper deals with the stress concentration analysis of 60°V-shaped or a partially-circular double edge notches in an infinite strip under remote tension. The stress field induced by a point force in a semi-infinite plate is used to solve these problems. The present results for semi-circular notch are in close agreement with other reports. The results calculated on the 60°V-shaped notches show that the Neuber formula gives an underestimated stress concentration factor in about 11% for a wide range of notch depth. However, in case of blunt notches, the Neuber solution of deep hyperbolic notches still gives a sufficient accuracy in engineering use. In addition, the stress concentration factors of 60°V-shaped notches are also represented by diagrams for wide use.
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Hiroyuki MATSUMOTO, Takashi HIRATA, Hirohiko OKUMURA
1985 Volume 51 Issue 467 Pages
1811-1817
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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To discuss the initiation of crack in the material, it will be important to get the knowledge about the singular stress at the bottom of the sharp notch. In this paper, dynamic singular stress field is discussed on the periphery of the periphery of the function part of the semi-infinite rod fixed on the surface of the semi-infinite body. It is assumed that the one dimensional torsional stress wave travels down the rod and arrived at the junction. Stresses on the rod and the semi-infinite body are analyzed based on the dynamic theory of elasticity and Laplace transformation method. An integral equation is solved numerically in the transformed domain. Stresses near the function and the generalized stress intensity factor are calculated from the above results by using the numerical inversion of the Laplace transformation.
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Kiyotsugu OHJI, Shiro KUBO, Takahide SAKAGAMI
1985 Volume 51 Issue 467 Pages
1818-1827
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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An electric potential CT (Computer Tomography) method was proposed, in which data on electric potential distribution were computer-processed by inverse analysis to estimate location, shape and size of two-and three-dimensional cracks. Two inverse analysis schemes were formulated in terms of the boundary element equations In one scheme the boundary integral equations were solved for quantities on unprescribed boundaries. Cracks were identified as flux-free boundaries. In the other scheme the boundary element solution of electric potential for an assumed crack profile was compared on free boundaries with the observed values. The crack profile which minimized the square sum of residuals, was employed as the most probable one. Computer simulations of measuring locations and sizes of several types of two-dimensional cracks demonstrated potential of the proposed CT method.
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Masaki SHIRATORI, Toshiro MIYOSHI, Katsumi TANIKAWA
1985 Volume 51 Issue 467 Pages
1828-1835
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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A weight function method has been developed to analyze the stress intensity factors for surface cracks which are subject to arbitrarily distributed surface stresses. The method is based upon the superpositon of the unit distributed load at each nodal point on the cracked surface. It can be easily incorporated with the ordinary three dimensional finite element code which utilyzes the 20-noded isoparametric elements with quadratic shape functions. Some examples in the paper show that the method guarantees the reasonable accuracy and that it is effective especially for the analysis of unsteady thermal stress problems.
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Katsuhiko WATANABE, Masahiro TSUGAI
1985 Volume 51 Issue 467 Pages
1836-1844
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The general condition by which the rate of crack growth is controlled is discussed based on the concept of crack energy densityε, and especially the parameters of creep crack growth rate are proposed, that is, it is shown that the average values of ∂^^∼ε
t/∂t, ∂^^∼ε
x1/∂X
1 concerning withεwhich correspond to the increase rate and the gradient ofεat the crack tip respectively are the parameters of creep crack growth rate based on the creep crack model in which a crack extends discontinuously with respect to time. And the crack growth of center notched specimen in tensile creep under plane stress condition is simulated by means of Finite Element Method. In the analysis, the condition of constantε
c(critical value ofε) is used. The validities of ∂^^∼ε
t/∂t, ∂^^∼ε
x1/∂X
1 as parameters of creep crack growth are numerically verified through this analysis.
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Kenji MACHIDA, Masanori KIKUCHI, Hiroshi MIYAMOTO
1985 Volume 51 Issue 467 Pages
1845-1851
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The three-dimensional elasto-plastic analyses are carried out by using the finite element method for CCT specimens of four kinds of thickness(B=200, 18, 6, 4mm). Inelastic analyses, there is no significant difference between the straight and the curved crack front specimens in the distribution of J-integral along the crack front. In elasto-plastic analyses, the distributions of J
x and COD along the curved crack front and the J
x along the crack front, which is independent of thickness of specimen. But, there is a significant difference between the 4mm thick specimen and the thicker specimens than 4 mm. The thickness effects are discussed from the distributions of J
x along the crack front and the plastic zone profiles. Finally, the availability of J
R value is examined, which is evaluated from the load versus displacement curve by using Rice's formula.
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Toshiro MIYOSHI, Yuichiro YOSHIDA, Masaki SHIRATORI
1985 Volume 51 Issue 467 Pages
1852-1857
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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In this paper the evaluation of Leak-Before-Break for pates with a surface crack has been carried out by the Line Spring Method. The COA criterion is used for the crack growth analysis and the load-displacement curves of surface cracked plates under tension are obtained for various crack geometries. The load-displacement curves are classified into two types. One shows the crack penetration after the maximum load, and another shows the crack penetration before the maximum load. Under the load controlled system, the latter satisfies Leak-Before-Break while the former does not. Next, the effect of the initial geometry of surface cracks to Lead-Before-Break is shown by LBB diagram. The tearing in stability and Leak-Before-Break of surface cracked plates can be evaluated by this diagram.
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Z.G. WANG, Tatsuo INOUE
1985 Volume 51 Issue 467 Pages
1858-1863
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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Butt-welding process of thin plates is analysed by finite element method when considering coupling effect between stress (strain), temperature and liquid-solid phase transformation. Constitutive equation employed is the modified viscoplastic one proposed by the authors which accounts for the material behavior of liquid, time-dependent inelastic solid as well as time-independent plastic one occuring in the wide range of temperature even above melting point. Calculated distributions of temperature and stresses are partly demonstrated in bird-eye views, and temperature profile and residual stresses are measured by thermocouples and by use of X-ray diffraction technique, respectively, to verify the theory proposed.
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Yoichi OBATA, Shinobu KOHNO
1985 Volume 51 Issue 467 Pages
1864-1871
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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A new approach to describe the time-independent tensile stress-strain curve is presented by means of the concept of the field of resisting force against the movement of dislocations. The cyclic plasticity model proposed in the previous paper based on this concept indicates that a stress-strain relation in the steady state can be expressed by three internal state variables concerned with such field and microscopic structures. In this paper, a tensile stress-strain relation with different type of yielding can be described by reflecting the microscopic behaviors such as the catastrophic increase of movable dislocation density at the early stage of plastic deformation in the change of one of these three variables. This description has provided satisfactory agreement with each experimental curve for carbon steel and brass with a wide range of strain.
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Yoshihiro TOMITA, Akio SHINDO, Young Suk KIM
1985 Volume 51 Issue 467 Pages
1872-1878
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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This paper deals with the nonaxisymmetric bifurcation of incompressible thick-walled circular tubes subjected to drawing at the outer surface under the plane strain condition. The influence of the yield stress, the hardening rate and the shape of the tubes upon the bifurcation behaviour is investigated. The results show that the short wavelength surface mode is the first bifurcation mode encountered in the deformation history for thick tubes with high work hardening rate and conversely, the long wavelength mode is that for thin tubes with low work hardening rate. The yield stress does not affect the bifurcation behaviour. The surface mode extends to the deep part of the tube as the workhardening rate decreases.
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Noriyuki MIYAZAKI, Tsuyoshi MUNAKATA
1985 Volume 51 Issue 467 Pages
1879-1885
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The finite element method is applied to creep buckling of a circular cylindrical shell under axial compression. In the finite element formulation, nonlinear strain-displacement relation is employed and creep strain is treated as an initial strain within a small time increment. Not only the axisymmetric mode but also the bifurcation mode of creep buckling are considered in the analysis. The critical time for creep buckling is defined as either the time when a slope of a displacement vs. time curve becomes infinite or the time when bifurcation buckling occurs. The creep buckling analyses are carried out for an infinitely long, axially compressed circular cylindrical shell. The numerical results are compared with available analytical ones and experimental data.
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Tadaharu ADACHI, Sadayuki UJIHASHI, Hiroyuki MATSUMOTO
1985 Volume 51 Issue 467 Pages
1886-1892
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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The impulsive response of a fluid-filled finite circular cylindrical shell with both ends clamped due to waterhammer waves is analysed on the basis of the three axisymmetric shell theories and the potential theory for perfect fluid. In the analysis Mirsky-Herrmann's theory including the influence of the transverse shear deformation, Flugge's theory as the accurate classical theory and the simplified theory most frequently used are employed and it is assumed that the influence of the fluid-shell interaction is neglibible. As a result, it is shown that if the accurate bending moments and the shear force are required, the use of Mirsky-Herrmann's theory is recommended. The numerical inversion of Laplace transformation by the use of the FFT algorithm contributes the reduction of CPU time and the improvement of the accuracy of results.
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Naoki ASANO
1985 Volume 51 Issue 467 Pages
1893-1899
Published: July 25, 1985
Released on J-STAGE: February 21, 2008
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This paper investigates that an impact contact force can be expressed as the product series of the penalty functions and the subsidiary contact conditions on a contact area between two bodies. Using the expression of the impact force, all the subsidiary contact conditions are relaxed in a virtual work principle for two bodies, and a penalty function method can be transformed from the concept of a least square method into that of a virtual work method. The use of a virtual work principle makes it easy to formulate a finite element method (FEM). Then, this paper also presents a virtual work principle with penalty functions for various impact contact states of two bodies. A FEM based on this principle is applied to a two-dimensional problem for the longitudinal impact of two bodies. The mean value of impact force by the FEM agrees well with the value from the theory of propagation of one-dimensional elastic stress wave.
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