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Kenji HATANAKA, Tatsuro FUJIMITSU, Hideaki WATANABE
1986 Volume 52 Issue 475 Pages
579-586
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Min Gun KIM, Kunihiro YAMADA, Takeshi KUNIO
1986 Volume 52 Issue 475 Pages
587-592
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Hideo KANESHIRO, Tateki YAFUSO
1986 Volume 52 Issue 475 Pages
593-600
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Terumi YAMAMOTO, Tosimitu TUMURA
1986 Volume 52 Issue 475 Pages
601-607
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Hisaaki TOBUSHI, Yoshio OHASHI, Kozi OSAWA
1986 Volume 52 Issue 475 Pages
608-615
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Kenichi KOBAYASHI, Shinichi ABE, Teruyoshi UDOGUCHI
1986 Volume 52 Issue 475 Pages
616-624
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Naotake NODA, Yasuhiro MATSUNAGA
1986 Volume 52 Issue 475 Pages
625-630
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Hitoshi WADA, Yutaka TAKAGI, Tohru NISHIMURA
1986 Volume 52 Issue 475 Pages
631-637
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Masanori KIKUCHI, Hiroshi MIYAMOTO, Satoshi HIRAOKA
1986 Volume 52 Issue 475 Pages
638-644
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Hitoshi MORITOKI, Shinzo NISHIMURA
1986 Volume 52 Issue 475 Pages
645-654
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Keiro TOKAJI, Zenji ANDO, Koshi NAGAE
1986 Volume 52 Issue 475 Pages
655-662
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Characteristics of fatigue crack propagation have been investigated in a low carbon steel and a high tensile strength steel to evaluate the effect of sheet thickness. Crack propagation data are generated over a wide range of growth rates, from 10
-8 to 10
-3 mm/cycle, for load ratios of 0.05 and 0.70 at room temperature in laboratory air. Particular emphasis is placed on behaviour at near-threshold growth rates. Near-threshold fatigue crack propagation behaviour is found to show a marked sensitivity to sheet thickness, and near-threshold growth rates decrease and threshold values increase with increasing sheet thickness. Roughness- and oxide-induced crack closure are proposed as a mechanism for the effect of sheet thickness on near-threshold fatigue crack propagation. It is also shown that the requirement for specimen thickness recommended by ASTM, W/20≤B≤W/4, is not valid for near-threshold fatigue crack propagation.
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Toshio HATTORI, Sooji SAKATA, Hiroo OHNISHI
1986 Volume 52 Issue 475 Pages
663-671
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Slipping behavior and deformation of a disk/blade dovetail assembly are analysed using a finite element method, a program developed for these contact problems. To analyse the problems with high accuracy it is necessary to use an exact frictional coefficient. The frictional coefficient is obtained through a pull-bend combined loading test. The blade damping capacity of the disk/blade dovetail assembly is calculated taking into account the slipping behavior. The calculated results coincide well with those of experimental results. The fretting fatigue strength is also estimated based on the calculated results of stress distribution on the contact surface. Finally, these calculated results are confirmed by the measurement of dovetail slot stresses under actual operating loading conditions.
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Junichi OKAMOTO, Masao SHIMIZU
1986 Volume 52 Issue 475 Pages
672-676
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Fatigue crack growth tests were preformed on austenitic stainless steel subjected to repeated thermal shocks using a specially designed test system for thermal shock fatigue, in which liquid air is sprayed onto the center of a disk-shaped specimen heated to about 200°C. The fatigue crack growth was found to occur while producing the striation on the fracture surface each time a thermal shock is applied. The crack growth characteristics in thermal shock fatigue can be well explained by the results of analysis of thermal stress intensity factor (SIF). The crack propagation rate da/dN achieves its maximum at the same crack length as in the curve giving the relationship between SIF and the crack length. The results of the observation have also been described on the initiation and propagation of small fatigue cracks at the notch root.
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Tadashi OHYOSHI, Kimihisa MIURA
1986 Volume 52 Issue 475 Pages
677-680
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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An experimental study of mechanical transverse impact on an elastic plate was made. The transient wave-forms are explained in consideration of the mechanical energy propagation velocity. The velocity depends on the wave propagation modes. To detect the higher mode waves, a tiny hard plastic bead launched by air pressure from a thin glass tube and a piezo-electronic effect sensor are used. A comparision between experimental energy arrival times and theoretical ones, shows that the way explaining the transient behaviors of an elastic plate, developed here, may be well viable.
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Katsutoshi YAMADA
1986 Volume 52 Issue 475 Pages
681-689
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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A transient thermal stress problem is solved analytically for a U-shaped edge notch in a semi-infinite plate in which the straight and notch edges have a prescribed temperature. The transient thermal stress concentration factors are computed numerically for the U-shaped notches having a notch-depth/notch-radius of up to 20, and the results are shown in the form of tables and figures. The stress concentration factors of steady state, which correspond to those under compression, are compared with other results available and very good agreements are found between them.
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Fumihiro ASHIDA, Naotake NODA
1986 Volume 52 Issue 475 Pages
690-696
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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The present paper is concerned with the three-dimensional transient thermal stress problem in a transversely isotropic finite circular cylinder subjected to an eccentric partial heat source on an end surface, and the convective heat losses into the surrounding medium from the surfaces. This problem is analyzed by means of the transversely isotropic potential function method to stresses. For numerical examples, the temperature and thermal stresses were calculated for a graphite which belongs under a transverse isotropy and compared with those of isotropy. The effects of the length of the circular cylinder on the temperature and thermal stresses were researched.
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Keiichi WATANUKI, Hideyuki OTAKI, Yoshio ISHIKAWA
1986 Volume 52 Issue 475 Pages
697-704
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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The higher accuracy and performance of machine elements are required, the disk liked internal gear are widely used--inverse Geneva gear, spline and so on. But the stress distribution and deformation when a load is applied to its boundary has hardly analyzed. Then, in this report the author has analyzed the stress distribution and deformation of the disk liked internal gear by using complex stress function. This method makes it possible to get any profile by using mapping function to express the machine elements, and to analyze their stress distribution and deformation correctly and easily by above stress function.
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Yasuro NISHIDA, Yasuhide SHINDO, Akira ATSUMI
1986 Volume 52 Issue 475 Pages
705-711
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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This paper deals with the problem of diffraction of horizontally polarized shear waves of arbitrary profile by a running crack located at the interface of two-bonded dissimilar elastic solids. A set of moving coordinate systems attached at the center of the running crack and a new time parameter are employed to obtain the basic equations of motion for two dissimilar elastic half spaces. By the use of Laplace and Fourier transforms we reduce the problem to a pair of dual integral equations. The solution to the dual integral equations is expressed in terms of a pair of Fredholm integral equations of the second kind having the kernel of a finite integration. Dynamic stress intensity factor for an incident wave with a step function profile is obtained as a function of the speed of crack propagation, the angle of incidence, the material properties, and time, and is shown graphically.
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Hideaki NOZAKI, Yasuhide SHINDO, Akira ATSUMI
1986 Volume 52 Issue 475 Pages
712-719
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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This paper is concerned with the axisymmetric ealstodynamic response of a long cylinder with a pennyshaped crack under normal impact, which is bonded to an infinite medium with different elastic constants. The problem is reduced to that of solving a pair of dual integral equations in the Laplace transform domain. Using an integral transform technique, the dual integral equations are further reduced to a Fredholm integral equation of the second kind. The dynamic stress intensity factor is obtained numerically, and the effects of the geometrical configurations and the material properties of the composite material on the dynamic stress intensity factor are shown graphically. Two limiting cases in which the surface of the cylinder is stress free and is fixed are included.
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Kiyotsugu OHJI, Shiro KUBO, Masahiko IWASAKI
1986 Volume 52 Issue 475 Pages
720-726
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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The authors have pointed out previously that the modified J-integral, J', near a creep crack tip is extremely high under the small-scale-creep conditions. Also, the J'-values in the transient creep, in which hardening exceeds recovery, are much higher than those in the steady-state creep, where an equilibrium between hardening and recovery is attained. The interaction of these two effects may multiply the increase in the J'-values during the transient creep. This paper is concerned with finite element simulation of this combined effect. The Robinson's model was employed to account for the effect of hardening and recovery during creep. It was found that the small-scale-creep effect was predominantly responsible for the increase in the J'-values during the initial part of loading time. The behavior of J' was explained in terms of the sizes of the creep-dominated region and the steady-state creep region.
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Katsuhiko WATANABE, Hideyuki AZEGAMI
1986 Volume 52 Issue 475 Pages
727-735
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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The objective of this study is to propose a practical method to evaluate the fracture resistance of a stably growing crack by crack energy density and to verify it through applications of the method to actual stable crack growth problems. The contents of this report are as follows: (1) More refined investigation of the relationship obtained before between initial crack length, load-displacement curves and the crack energy density which holds until a crack starts to grow is shown by using two crack models. (2) A relationship between initial crack length, present crack length, load-displacement curves and the additional rate of crack energy density caused by crack extension which holds generally to a growing crack is derived by using the same crack models as in (1). (3) A method to evaluate the fracture resistance of a stably growing crack from load-displacement curves which can be easily obtained by experiments is proposed, based on the relations above.
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Katsuhiko WATANABE, Hideyuki AZEGAMI, Yasuo HIRANO
1986 Volume 52 Issue 475 Pages
736-743
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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The method proposed in the 1st Report for evaluating the fracture resistance of a stably growing crack by crack energy density is applied to the stable crack growth problems of thin plates, and its applicability and validity are confirmed. That is, the experiments of stable growth fractures of thin single-edge cracked specimens with different initial crack lengths under bending moment, and thin center cracked specimens also with different initial crack lengths under tensile force are carried out. The fracture resistances expressed by additional rates of crack energy density and crack energy density are evaluated, based on the results. When fracture modes are almost the same, fracture resistances have almost the same values regardless of initial crack lengths, and their values vary only corresponding to the change of fracture mode caused by crack extension. Also, the difference of specimen types has no remarkable influence on their values.
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Masumi SAKA, Satoshi TANAKA, Hiroyuki ABE
1986 Volume 52 Issue 475 Pages
744-751
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Crack tip blunting and crack initiation subjected to mixed mode loading of Mode I and Mode II were examined under the plane strain condition with large scale yielding. Fracture toughness tests were performed for tension specimens with double-edge cracks inclined to the loading axis. Elastic-plastic finite element analysis, based on finite deformation theory, was also carried out in order to understand the development of the crack tip blunting and the plastic strain concentration in the vicinity of the crack tip due to the blunting. The generalized COD, δ
r, was newly introduced for a ductile crack under mixed mode loading. It was shown that δ
r dominates the deformation in the vicinity of the blunted crack tip, independently of the crack angle, so that δ
r is useful as a fracture parameter. It was verified that the critical values for the crack initiation of δ
r and of the plastic work done, W^^
p, in the vicinity of the crack tip, were independent of crack angle, in contrast to the J-integral and the usual COD, δ.
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Hirokazu OZE, Yukio IWASHIMIZU
1986 Volume 52 Issue 475 Pages
752-757
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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It is shown that the spectrum analysis of ultrasonic transverse waves is a useful tool for the acousto-elastic measurement of the difference and directions of principal stresses. The stress distribution chosen for the experiment is that in a center-holled plate specimen under tension. Ultrasonic transverse waves are incident normal to the specimen, and spectrums of the echos are analyzed. The transducer commonly used for sending and receiving waves is rotated to find the direction of incident vibration for which the spectral amplitude vanishes at some frequency. Such transducer direction and frequency are measured not only in a stressed state but also in a reference state of the specimen, and used for the acousto-elastic law in a slightly orthotropic material to determine the directions and difference of the principal stresses. In this experiment, the polarization directions of transverse waves changes only a little by the stress, and the precise measurement of this is required in a further study.
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Masataka TOKUDA, Nobutada OHNO, Jan KRATOCHVIL
1986 Volume 52 Issue 475 Pages
758-764
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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Many important features observed in the inelastic behaviour of polycrystalline materials are caused for by a non-uniformity of microstructure and changes during the deformation process. Using the slip theory, a simplified model of a polycrystal which incorporates non-uniformity is presented, and a set of compact and reliable inelastic constitutive equations are developed, on the basis of the model, in a rate-form. The equation can reproduce deformation history effects and rate effects at an elevated temperature observed in a set of systematic experiments, with reasonable accuracy.
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Osamu WATANABE, Hideomi OHTSUBO
1986 Volume 52 Issue 475 Pages
765-772
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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This paper presents analysis of elastic stress and torsion buckling of U-shaped bellows using ring elements. The expansion joint is considered to be composed of the two toroidal sections and inner-connecting annular plates. The general thin shell theory is employed to derive strain-displacement relations of shells and plates, valid for any loadings. Numerical examples under internal pressure or axial loading are described and compared with the results of existing appropriate analysis. The fundamental aspects of torsional buckling, which have not been studied previously, will also be investigated.
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Naoki ASANO
1986 Volume 52 Issue 475 Pages
773-780
Published: March 25, 1986
Released on J-STAGE: February 21, 2008
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This paper presents that an impact contact force can be expressed as the product series of penalty functions and subsidiary contact conditions having relative movement components between two bodies on a contact surface. A penalty function type of virtual work principle for various contact and separate states of two bodies is formulated by using the expression of the impact force. This principle is most effective for solving a general impact response of the alternation between contact and separation, and a stress wave propagation response of cracked structures with open and/or closed states on a cracked surface. This is because of both the use of the relative components and the relaxation of all the subsidiary conditions in this principle. A finite element method (FEM) based on this principle is applied to a two- dimensional analysis for longitudinal impact of two uniform rods. The mean value of impact forced by FEM results coincides well with the value from the theory of one-dimensional elastic stress wave propagation.
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