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Masaharu KAGE, Hironobu HISITANI
1985 Volume 51 Issue 461 Pages
3-9
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Min Gun KIM, Kunihiro YAMADA, Takeshi KUNIO
1985 Volume 51 Issue 461 Pages
10-16
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Akira TSURUI, Hiroshi ISHIKAWA
1985 Volume 51 Issue 461 Pages
17-22
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Sueo KAWAI, Kenichi KASAI
1985 Volume 51 Issue 461 Pages
23-30
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Akira TSURUI, Hiroshi ISHIKAWA
1985 Volume 51 Issue 461 Pages
31-37
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Yoshio OHASHI, Eiichi TANAKA, Masahiro OOKA
1985 Volume 51 Issue 461 Pages
38-46
Published: January 25, 1985
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Tsuneo TSUIJI, Tsutomu YAMASHITA
1985 Volume 51 Issue 461 Pages
47-53
Published: January 25, 1985
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Hironobu NISITANI, Nao-aki NODA
1985 Volume 51 Issue 461 Pages
54-62
Published: January 25, 1985
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Yoshihiro SUGANO, Toshiya MAEKAWA
1985 Volume 51 Issue 461 Pages
63-71
Published: January 25, 1985
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Hiromasa ISHIKAWA, Horst LIPPMANN
1985 Volume 51 Issue 461 Pages
72-80
Published: January 25, 1985
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Kazuo TAKAKUDA, Takashi KOIZUMI, Toshikazu SHIBUYA
1985 Volume 51 Issue 461 Pages
81-89
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Kiyotsugu OHJI, Shiro KUBO, Toru SHIBATA, Keiji OGURA
1985 Volume 51 Issue 461 Pages
90-97
Published: January 25, 1985
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Noriyuki MIYAZAKI
1985 Volume 51 Issue 461 Pages
98-106
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Toshiaki HISADA, Shigeru NAKAGIRI
1985 Volume 51 Issue 461 Pages
107-115
Published: January 25, 1985
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NAKAGIRIShigeru, Keiko SUZUKI, Toshiaki HISADA
1985 Volume 51 Issue 461 Pages
116-122
Published: January 25, 1985
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Hiroaki KATORI, Toru NISHIMURA, Katsuhiko MURASE
1985 Volume 51 Issue 461 Pages
123-131
Published: January 25, 1985
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Mitsuru YANO
1985 Volume 51 Issue 461 Pages
132-135
Published: January 25, 1985
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The fatigue tests were carried out to study the effects of elasticity and compactness of the graphites for two kinds of parlitic malleable irons, one was heat-treated by direct oil quenching and tempering process and the other was heat-treated by reheating, oil-quenching and tempering process. The material produced by direct oil quenching and tempering process in which graphites could be considered to be compressed by matrix, had about 20% higher fatigue strength in rotary bending fatigue test than that produced by reheating, oil-quenching and tempering process in which graphites exist more loosely. The similar results were obtained in torsional pulsating fatigue test on the universal joint yokes made by these two materials. Thus it was concluded that the fatigue strength was influenced by elasticity and compactness of graphites.
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Chitoshi MASUDA, Satoshi NISHIJIMA, Hideshi SUMIYOSHI, Eiichi NAKATA
1985 Volume 51 Issue 461 Pages
136-141
Published: January 25, 1985
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A method for automatic evaluation of fatigue striation was proposed. The principle of the method is consisted of one dimensional Fast Fourrier Transformation Analysis (FFTA) of image signal from the scanning electron microscope and easily accessible with personal computers. Fracture surfaces of steel, aluminium alloy and titanium alloy specimens were prepared by constant or variable amplitude fatigue tests and examined. For constant amplitude fatigue several peaks were revealed on the power spectre diagram by FFTA : the first corresponding to macroscopic inclination of the facet, the second representing the mean striation spacing and the third exhibiting more detailed structures or slip lines within the striation. For variable amplitude fatigue by block programmed cycling the power spectre diagram comprized many separate peaks in which the highest was found to represent the trace of crack propagation by one programme block. Striation spacing obtained from FFTA agreed well with results from direct measurement by conventional methods.
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Jong-Hyung LEE, Hideo KOBAYASHI
1985 Volume 51 Issue 461 Pages
142-147
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Short fatigue cracks initiated at the notch root were successfully detected at a fairly high accuracy by the ultrasonic amplitude calibration method for the notched compact specimens of an A508-3 steel. Crack closure measurements by the ultrasonic and back-face strain compliance methods were also performed. Crack growth characteristics at the notch root are similar to those of delyed retardation caused by a single peak overload. Also, transitional behavior from short cracks to long cracks was interpreted in terms of effective stress intensity ΔK
eff. The relation between crack growth rate da/dN and ΔK
eff for short cracks shows a fairly good agreement with those for long cracks.
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Haruo NAKAMURA, Hideo KOBAYASHI, Satoru YANASE, Hajime NAKAZAWA
1985 Volume 51 Issue 461 Pages
148-151
Published: January 25, 1985
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Crack closure characteristics in fatigue crack growth were examined using the modified Dugdale model developed by Newman. The model can leave several elements in the wake of the advancing crack tip. First, plasticity induced crack closure was analyzed. The results gave a fairly good agreement with those obtained by finite element analysis or the Dugdale model. Applications of the model to crack surface roughness and oxide induced crack closure were attempted. Roughness or oxide debris near the crack tip causes a increase in opening stress intensity K
op. On the other hand, K
op decreases when they are located at the first contact point during unloading. It is also demonstrated that K
op increases as roughness of crack surfaces or the strength of oxide debris increases.
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Hideo KOBAYASHI, Haruo NAKAMURA, Satoru YANASE, Hajime NAKAZAWA
1985 Volume 51 Issue 461 Pages
152-155
Published: January 25, 1985
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The role of crack surface roughness and oxide debris on crack growth characteristics was examined by finite element method for a compact specimen. Several asperities were attached on the crack surfaces. The analysis shows the influence of rigidty and strength of the asperities, asperity length, asperity thickness and the distance from the crack tip. The results were interpreted in termes of the opening stress intensity K
op and the effective CTOD, Δσ
o*. It is concluded that the strength of asperities has a marked influence on K
op. On the other hand, rigidty is a controlling factor of Δσ
o*. The analysis also gives a support to resolve the uncertainty concerning the experimental determination of K
op using back face strain technique.
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Satoshi NISHIJIMA, Takayuki ABE, Chitoshi MASUDA, Hisashi HIRUKAWA
1985 Volume 51 Issue 461 Pages
156-160
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Corrosion fatigue property was investigated for quenched and tempered carbon steel and Cr-Mo steel under rotating bending in 3% NaCl aqueous solution at frequencies from 0.03 to 30 Hz and for test duration up to 10000 hours. Fatigue behaviour was found similar for the two steels: fatigue strength was monotonously decreased with increasing number of cycles and decreasing test frequency without presenting tendency of stabilization. The acquired data could be fitted by a simple hypothetical equation, log σ=A+(β/m)log f - k log(1+αt)-(1/m)log N where σ, N, f, t are stress, number of cycles, frequency, and test duration, respectively, and the other constants.
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Ryoji YUUKI, Eiji MURAKAMI, Hideo KITAGAWA
1985 Volume 51 Issue 461 Pages
161-166
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Corrosion fatigue tests of a high tension steel and a stainless steel in 3.5% NaCl solutions were carried out under various in-plane biaxial stress conditions. The effects of biaxial stresses on the corrosion fatigue crack propagation properties were investigated, compared with the date in air. The fatigue crack growth rates of high tension steel were accelerated by corrosive environment in order of over-cathodic potential, free corrosion and anodic potential and no effects of biaxial stresses appeared. The fatigue crack growth rates of stainless steel at free corrosion were accelerated more than that of high tension steel and the significant effects of biaxial stresses appeared because the stress levels were relatively high.
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TAKAMATSU Tohru, ICHIKAWA Masahiro
1985 Volume 51 Issue 461 Pages
167-170
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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In order to investigate the J-integral resistance curve (J-R curve) and the unstable fracture criterion of the sheet specimens under Mode II loading condition, Mode II testing have been carried out on center cracked sheet specimens of 2024-T 3 aluminum alloy. The dependence of the J
II-R curve (J-R curve for Mode II loading) on the specimen geometry is examined experimentally. Furthermore, the influence of the compliance of the loading system on the unstable fracture condition is studied experimentally, and the applicability of the tearing instability criterion proposed by Paris et al. to the Mode II loading condition is investigated. It is shown that the influence of the specimen geometry on the J
II-R curve is relatively small. The unstable fracture point estimated by the tearing instability criterion is in good agreement with the experimental result, and it is shown that the tearing instability criterion is applicable to the Mode II loading condition.
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Toshiro MIYOSHI, Yuichiro YOSHIDA, Masaki SHIRATORI
1985 Volume 51 Issue 461 Pages
171-174
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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In this paper, the stable crack growth of three dimensional surface crack has been analyzed by the Line Spring Method. The elastic-plastic stiffness of a line spring element is evaluated by the complementary energy of the single edge notched specimen. The COA criterion is used for the crack growth analysis and the change of the surface carck configuration is analyzed with increasing applied stress. The penetration loads are estimated for the various surface crack configurations and are compared with those the net section stress criterion. The qualitative agreement is obtained between two results. But, for some configurations, the tearing instability arises before the crack penetration and the net section stress criterion becomes invalid for those configurations.
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Yukio TAKAHASHI, Genki YAGAWA
1985 Volume 51 Issue 461 Pages
175-178
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Study on unstable ductile fracture of nuclear primary piping becomes very important from the viewpoint of plant safety because of frequent discoveries of the stress corrosion cracking. The authors have performed the analysis of ductile crack extension in center cracked plate specimens of type 304 stainless steel. In this study, pipes with a circumferential crack are taken as an object of the analysis. At first, a simple estimation formula for the J-integral of the non-growing and growing cracks is proposed and validity is checked using the fully plastic solutions. Next, ductile crack extension is analyzed by the three-dimensional finite element method. The J-integral obtained by the virtual crack extension method agrees well with the values obtained by the simple estimation formula up to the crack extension of about 40 mm. Finally, the dependency of the J-integral resistance curve on the specimen geometry is examined by the comparison to other data.
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Hideo KITAGAWA, Yuuji NAKASONE, Mineaki IIDA
1985 Volume 51 Issue 461 Pages
179-183
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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The present paper investigates statistical variation in the growth rates (da/dN) of multiple small surface cracks in a JIS S 45 C steel subjected to rotating bending fatigue in air. The growth rates of the cracks were found to follow a power law : da/dN = C(σa√((πa))
m where a is the half surface length of each crack and σ
a the applied stress amplitude. C and m in the law varied among the multiple cracks, and obeyed the normal and the log-normal distribution, respectively ; nevertheless, they were related to each other by C = A/B
m where A and B are some constants. The 95% confidence limits of the variation in da/dN of the multiple small surface cracks were calculated by using these statistical data.
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Masafumi SENOO, Toru NISHIMURA, Iwao KONDO, Kazuhisa MIYASHITA
1985 Volume 51 Issue 461 Pages
184-188
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Supersaturated solid-solutioning alloys of the Al-Si system up to 15at%Si were prepared by means of high pressure and high temperature techniques. A cylindrical specimen with a size of φ6×6 mm for the solid-solutioning treatment was preserved under the pressure of 5.4 GPa and the temperature of 600°C for 10 hours, and then quenched to room temperature. The elastic constants of thus obtained specimens were measured by a three dimensional resonance method. The Young's modulus E and shear modulus G of the solid solutions were very smaller than that of the two phase alloys, and also were varied to lower values with Si-contents. For example E=77.1 GPa of the two phase Al-10at%Si alloy was fallen to E=62.0 GPa of the solid solution. Density variations of the specimens were also discussed.
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Yoshikazu SANO, Hironobu NISITANI
1985 Volume 51 Issue 461 Pages
189-192
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Tensile tests of notched specimens whose minimum diameters were 10 mm and 20 mm, were carried out on an alloyed spheroidal graphite cast iron. It was proved that fracture condition of these specimens can be explained based on the concept of 'Linear Notch Mechanics'. In other words, tensile fracture behaviour of notched specimen mentioned above is controlled approximately only by the values of ρ and maximum elastic stress σ
maxe, independently of the other dimensions of the specimen.
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Yuzuru SAKAI, Nobukazu OGURA
1985 Volume 51 Issue 461 Pages
193-198
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Curve-fitting regression procedures for toughness data have been examined. The objectives of fitting curve in the context of the study of nuclear pressure vessel steels are (1) convenient summarization of test data to permit comparison of materials and testing methods ; (2) development of statistical base concerning the data ; (3) the surveying of the relationships between charpy data and fracture toughness data ; (4) estimation of fracture toughness level from charpy absorbed energy data. The computational procedures using the tanh function have been applied to the toughness data (charpy absorbed energy, static fracture toughness, dynamic fracture toughness, crack arrest toughness) of A 533 B cl.1 and A508 cl.3 steels. The results of the analysis shows the statistical features of the material toughness and gives the method for estimating fracture toughness level from charpy absorbed energy data.
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Hisakazu OGURI, Hiroomi HOMMA
1985 Volume 51 Issue 461 Pages
199-203
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Stable crack growth experiments for SM 50 A steel and 2017-T3 aluminum were carried out to obtain J
I-R curves under crack-line wedge loading and 3-point bending. J-integral value, which was computed by use of the formula for a growing crack recommended by ASTM, increased at different rates with the crack growth amount under both type loadings while the values at initiation equaled. Finite element analysis was made for the stable crack growth measured by the experiment to compute the J-integral value at the growing crack tip. In elasto-plastic materials, elastically unloaded region is left behind the growing crack tip. This region lets J-integral lose the path independency. J-integral value at growing crack tip was computed from the integration of J along the specimen outer contour and correction for the unloaded region. The computation results showed that the J-integral value at the crack tip was almost invariable while the crack grew and was independent of the loading type.
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Genki YAGAWA, Hiroyoshi UEDA, Yukio TAKAHASHI
1985 Volume 51 Issue 461 Pages
204-207
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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To estimate the possibility of LBB (Leak-Before-Break), one of the important design concept for the balance of the safety margin and the economy of the structure, it is necessary to investigate the behavior of the inner surface crack in the structure. In this paper, as the preliminary analysis for LBB of high ductile material, the fully plastic solution of a semi-elliptical surface crack (a/c=0.6, a/t=0.2) in the infinite plate under tension is obtained. Several interesting trends are recognized from the solution obtained. First, the dependence of the elastic stress intensity factor to Poisson's ratio is small in this case. In the second place, as the power hardening exponent increases, the fully plastic solution of J-integral has the tendency to increase steeply with the eccentric angle of the crack.
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Abdelmajid FATNASSI, Yoshihiro TOMITA, Akio SHINDO
1985 Volume 51 Issue 461 Pages
208-211
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Non-axisymmetric buckling phenomenon seen during the nosing, sinking, and drawing of elastic-plastic thin circular tubes is investigated theoretically based upon Hill's bifurcation theory in conjunction with finite element approximation. The influence of the thickness of the tube to the initial mean radius ratio, the die semi-angle, the sinking zone and the exit radius, and the material properties including the transversely anisotropy of the tube on the buckling limit is investigated. It is revealed that the buckling limit is postponed when the thickness and the die semi-angle increase but conversely decreases as the yield stress σ
y, the hardening exponent n, and the average γ-value γ-<aν> increase Further, the existence of the sinking zone and the exit radius is found to have a suppressive effect on the critical drawing ratio.
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Osamu MAJIMA, Kunio HAYASHI
1985 Volume 51 Issue 461 Pages
212-216
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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The problems of elastic buckling and flexural vibration of variable thickness annular plates have been analyzed by the Galerkin method. Natural vibration modes of the constant thickness annular plate without in-plane force have been adopted as admissible functions. Numerical calculations were executed for the annular plates of linearly varing thickness with uniform in-plane force along the inner and/or outer edges. Asymmetric deformations were also taken into consideration in this procedure. It has become clear that whether the taper ratio has influence on the buckling mode depends on the specific boundary conditions at the inner and outer edges. The proposed method could be easily extended to the cases where the thickness variations were more complicated.
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Akiyoshi OKITSU, Shin MORISHITA, Kazufumi TORIYA
1985 Volume 51 Issue 461 Pages
217-221
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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In the present paper, the mechanical properties of perforated plates with rectangular arrays of holes are investigated mainly experimentally. Perforated plates have generally been used for the elements of constructions for the purpose of saving the materials and of light-weighing, however, the effects of perforation to the dynamic characteristics have not been discussed minutely. The perforated rectangular plates are dealt with as orthotropic ones herein, and its effective elastic modulus is estimated from the experiments of perforated beam elements with the same array of holes. Reasonance frequencies and several modes of the plate are measured by use of the time-average holography, and they show good agreement with calculated values estimated by Rayleigh's method. As a result, the perforated plates show less orthotropy than they have been expected, laser holography is the effective method is estimating dynamic characteristics of such perforated plates.
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Sitiro MINAGAWA, Kazuhito SHINTANI
1985 Volume 51 Issue 461 Pages
222-225
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Moving dislocations in anisotropic piezoelectric crystals are treated. The basic equations governing the displacement and electric potential are presented, and their solutions are given by the method of Green's functions. The elastic strain and electric fields are calculated from those solutions. They are expressed entirely in terms of the dislocation-density and dislocation-flux tensors by means of the volume integrals with respect to the region where there exist dislocations. The expressions are specialized into those for the fields of uniformly moving infinite straight dislocations in a cubic anisotropic crystal. The analytical expressions for those fields are given for a screw dislocation moving on a plane of symmetry.
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Shuichi FUKUDA
1985 Volume 51 Issue 461 Pages
226-230
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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As engineering mechanics is a fundamental tool for the design and/or production of machines or structures, many engineers use theoretical and/or experimental formulae in their daily work. But these formulae are applicable only under certain conditions, and more often than not it takes a considerable amount of expertise to make appropriate decisions on what kind of formulae should be applied for the given conditions. Although manuals are published to provide aids for this purpose, they cannot provide information deep enough to answer quite diversified requirements of an individual user. And in addition, as the progress of engineering mechanics is quite rapid these days, it is not easy to keep the contents of manuals up to date. This paper points out that by introducing logic programming technique, we can cope with such diversified requirements and can easily update the content through an interactive software system.
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Noriyuki MIKI, Kiyotsugu OHJI, Keiji OGURA, Akinobu KOBA
1985 Volume 51 Issue 461 Pages
231-236
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Methods of evaluating stress and strain concentrations in the elastic-plastic region under mode III loading were proposed on the basis of numerical analysis by a finite element method. In the case of small-scale yielding, the stress and strain concentration factors under mode III loading were estimated with good accuracy by using the master curves identically the same as those obtained previously under mode I loading. Under the large-scale and general yielding conditions, the maximum stress and strain at the notch root under mode III loading were successfully estimated by using similarly the previously obtained mode I master curves expressed in terms of J-integral. Several methods of deriving the master curves and a formula for calculating J-integral values with engineering simplicity were discussed. It was demonstrated that Neuber's rule was not valid even under the mode III loading and overestimated considerably stress and strain concentrations.
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Masumi SAKA, Mikio MURAOKA, Hiroyuki ABE
1985 Volume 51 Issue 461 Pages
237-241
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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An asymptotic solution is presented for the singular stress and strain fields near the tip of a steadily growing crack in an elastic-viscoplastic material under Mode III loading. By taking into account the experimental study made by Clark-Duwez in which no further increase of dynamic yield stress was observed when the strain rate exceeded the critical value, an intense strain region which behaves as an elastic-perfectly plastic material is introduced in the vicinity of the crack tip where this region is surrounded by the elastic-viscoplastic material. It is shown that the size of the intense strain region measured along the crack line is proportional to the velocity of the crack growth, and the singularity of the strain distribution near the crack tip is weakened by the intense strain region.
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Hironobu NISITANI, Dai-heng CHEN
1985 Volume 51 Issue 461 Pages
242-247
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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This paper is concerned with an analysis of closure behavior of fatigue cracks emanating from the edge of an elliptical hole. The crack closure model used is similar to that proposed by Budiansky and Hutchinson, however, the method of analysis is the body force method extended to the elastic-plastic problems. The following results were obtained. (1) If the notch root radii ρ and the maximum elastic stress in several notches are the same, then the reversed plastic zone, the effective fraction of load and the reversed crack tip opening displament of those notches are nearly the same, independently of the other notch geometries. This means that the 'Linear notch mechanics' is available for the problems of fatigue crack growth. (2) When a fatigue crack emanating from the edge of an elliptic hole grows, the reversed crack tip opening displament has a tendency to decrease in the range where the crack is small. This behavior is different from that of the fatigue crack formed in a smooth specimen.
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Tetsuyuki HIROE, Toshihide IGARI
1985 Volume 51 Issue 461 Pages
248-253
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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An application of the viscoplasticity theory based on total strain and overstress to the inelastic analysis at elevated temperature is examined experimentally. The monotonic and cyclic loading tests with the strain rate changes are carried out on 2·1/4 Cr-1 Mo steel at 600°C. The viscosity function which characterizes rate-dependency in the theory is extended as the function not only of overstress but also of strain for the elevated temperature application. The extended uniaxial model is shown to reproduce the inelastic stress and strain behavior observed in the experiment.
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Genki YAGAWA, Hidetoshi HASHIZUME, Toshihiko FUKUDA, Masazou KUROSAWA
1985 Volume 51 Issue 461 Pages
254-257
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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The C
* (modified J-integral) control creep experiment' system was developed using micro-computer. The system was applied to the C
*-constant control creep test of type 304 stainless steel CT specimen at 550°C. The test result showd that the C
* was successfully controlled in elevated temperature test with the developed system and the crack growth rate was almost constant under the secondary creep region and C
* constant condition.
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Yasushi NIITSU, Kozo IKEGAMI
1985 Volume 51 Issue 461 Pages
258-263
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Plasticity-creep interaction effect was experimentally investigated under changing temperature. The combined stress tests were performed on thin-wall tubular specimens of austenite stainless steel SUS 304 from room temperature to 600°C. Plastic behaviors at 600°C subsequent to creep pre-strain produced at room temperature and those at room temperature subsequent to creep pre-strain produced at 600°C were experimentally determined under various loading conditions. The stress strain relations obtained by these experiments were compared with the results calculated by the equiplastic strain surfaces. The influence of creep pre-strain at room temerature on subsequent plastic behaviors of high temperature was nearly equal to that of plastic pre-strain, but the influence of creep pre-strain at high temperature on plastic behaviors of room temperature were weaker than that of plastic pre-strain.
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KOSHIDE Shinichi
1985 Volume 51 Issue 461 Pages
264-267
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Strain distribution of graphite epoxy composite strips with a circular notch under tension are analysed by the Moire method. The strips are cross-plied composite and woven fabric composite, which are two kinds of fiber orientation, i.e, 0°/90° and ±45° to the loading direction. The results of the tensile tests indicate that the strain distribution of strips with a circular notch are greatly varied by the difference of fiber orientation for the both composites. The deformation behaviour and fracture situation for the each fiber orientation of the both composite strips are also clarified with the results.
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Yoshihisa MlNAKUCHI, Takashi KOIZUMI, Toshikazu SHIBUYA
1985 Volume 51 Issue 461 Pages
268-272
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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A quantitative measurement of contact pressure by means of ultrasonic waves using angle probes has been proposed to measure contact pressure distributions between two elastic beams. At first, in a proposed calibration method, the relation between mean contact pressure and sound pressure of reflected waves is obtained for various surface roughnesses by using calibration blocks made of the same material as the beams. Both sides of the laminated beams are compressed under locally uniform pressure, and the sound pressure of reflected waves is measured. The experimental results agree fairly well with the theoretical ones and the experimental ones obtained by a normal probe. It is clarified that the proposed ultrasonic method is practically useful.
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Yukio KOJIMA, Michito UTSUNOMIYA, Seiji NISHIDE
1985 Volume 51 Issue 461 Pages
273-276
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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For two types of load cell which includes a load-receiving member coupled to a support member by three or two parallel beams, temperature and strain distribution caused by step increase of surface temperature were calculated by using the finite element method. For the initial short duration about several seconds, load-sensing beams were deformed by the temperature gradient within the load-receiving member that had been exposed to a step increase of temperature. Beyond this short time, the beam deformation was caused by the temperature difference between the support member and the load-receiving member. Based on the observation of the transient behavior of beam deformation, the nature of zero-shift induced by transient temperature could be clarified. The mechanism of beam deformations suggested be the calculations was confirmed by a experiment using radiant-heat flux.
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Hisao TAKEYAMA, Yasuhisa SATO, Toshimi TOBE, Masana KATO, Nobuo TAKATS ...
1985 Volume 51 Issue 461 Pages
277-281
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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A modified split-Hopkinson-pressure-bar compression system which operates following a predetermined, constant or variable strain-rate course in specimen is developed and some of its applications are shown. Striker bars of nonuniform cross sections designed on the basis of the elastic-wave-propagation theory are used to generate desired shapes of incident loading pulse. It is shown that a striker bar having a shape of frustum of cone enables constant strain-rate testing throughout the deformation of specimen. The system is used to generate a nearly constant strain-rate in the specimens with different ratios of diameter to height. The dynamic stress-strain data free from the effect of friction between the specimen and tools are then obtained by extrapolating the results. The system is also applied to variable strain-rate tests to investigate the flow characteristics of metals and some examples are demonstrated.
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Seiichi OHTAKI, Akinobu KURIMURA
1985 Volume 51 Issue 461 Pages
282-285
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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Prof. G. Maier has investigated problems in which normality conditions with regard to plastic strain increments pertaining to the yield surface in stress space are not satisfied and work softening effects are to be considered by the aid of quadratic programming concepts in the theory of plasticity. Present authors applied this method for solving the elasto-plastic plane stress problem as the quadratic optimization in terms of displacement rates and plastic multiplier rates. The matrices are formulated in explicit forms and the program is coded using the quadratic programming technique for the problem of perforated tension strip. Finally a comparison is made between results obtained through the present method and the ordinary matrix method, and it is shown that the elasto-plastic problem is fairly tractable through the present method.
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ISHIKAWA Hiromasa, Shigeru TADANO
1985 Volume 51 Issue 461 Pages
286-290
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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To confirm the usability of Cellulose Acetate as model material for studying photoplasticity, the various mechanical and optical behaviour of Cellulose Acetate must be examined. In this paper, two essential tests for photoplasticity is represented. One is the relaxation test to investigate the viscosity of the material, and the other is the repeated loading test to understand the effect of the history of prestraining. As results of these tests, it was obtained that the relaxations of stress and fringe order are expressed by Maxwell models, and the rapid relaxations of stress and fringe order, especially in early stage of deformation, set limits to the usability of Cellulose Acetate. The repeated loading test shows that the relation between stress and strain, and the relation between stress and fringe order do not depend on residual strain and fringe order, and then cumulated plastic fringe order is represented by cumulated plastic strain in the linear equation.
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Shin-ichi NISHIDA, Kazuo SUGINO, Chikayuki URASHIMA, Hiroki MASUMOTO
1985 Volume 51 Issue 461 Pages
291-295
Published: January 25, 1985
Released on J-STAGE: February 21, 2008
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The high speed rail testing machine was invented to simulate the Shinkansen traffic conditions, especially the contact rolling problems between rail and wheel, in a laboratory. Its main properties are as follows: This machine was principally consist of a circular rail and two wheels contact rolling internally. Test piece; actual rail (for example, 12 m ×2 pieces), parent metals and welds. Wheel; two actual wheels, easily changeable system by of pressure, one way running direction. Radial load; simple mechanism and large capacity by centrifugal force and oil pressure, easily variable loading system. Thrust load; vertical oscillation of rotor by oil pressure actuator. Driving system; wheel driving. Pitch of rail sleepers; 580 mm. Atomosphere; air, fresh water and sea water. : the same condition as those of Shinkansen.
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