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Toshio SAKON, Tadayoshi ENDO
1985 Volume 51 Issue 471 Pages
2425-2432
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Toshihiko KUSUMOTO, Hideo KOBAYASHI, Hajime NAKAZAWA
1985 Volume 51 Issue 471 Pages
2433-2440
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Yan-Lin LU, Hideo KOBAYASHI, Hajime KANAZAWA
1985 Volume 51 Issue 471 Pages
2441-2449
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Hideaki KASANO, Hiroyuki MATSUMOTO, Ichiro NAKAHARA
1985 Volume 51 Issue 471 Pages
2450-2458
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Ryohei ISHIDA
1985 Volume 51 Issue 471 Pages
2459-2464
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Naotake NODA
1985 Volume 51 Issue 471 Pages
2465-2473
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Toyomi UCHIYAMA, Eiichiro TSUCHIDA
1985 Volume 51 Issue 471 Pages
2474-2481
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Hiroshi KIMOTO, Saburo USAMI, Hiroshi MIYATA
1985 Volume 51 Issue 471 Pages
2482-2488
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Toshiro MIYOSHI, Nobutoshi SAGAWA, Tadashi SASSA
1985 Volume 51 Issue 471 Pages
2489-2497
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Shunichi KAWANO, Shigetoshi SHIMIZU, Fujio YAMANE, Masaaki TANAKA
1985 Volume 51 Issue 471 Pages
2498-2506
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Atsumi OHTSUKI
1985 Volume 51 Issue 471 Pages
2507-2516
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Sumio MURAKAMI, Yukio SANOMURA, Mituru HATTORI
1985 Volume 51 Issue 471 Pages
2517-2525
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Yuji SUGITA
1985 Volume 51 Issue 471 Pages
2526-2535
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Yukio TADA, Yasuyuki SEGUCHI, Tadashi SOU
1985 Volume 51 Issue 471 Pages
2536-2543
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Yoshio ARAI, Hideo KOBAYASHI, Hajime NAKAZAWA
1985 Volume 51 Issue 471 Pages
2544-2553
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Masahiro JONO, Jiho SONG, Hidetomo ITOH
1985 Volume 51 Issue 471 Pages
2554-2559
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Using very small-sized specimens of a special type, the fatigue crack growth and closure of high tensile strength steel, HT80, containing short precracks, were studied with a refined, minicomputeraided unloading elastic compliance monitoring technique. The effect of the stress relief annealing in vacuum on the growth behavior of short fatigue cracks was also investigated. The closure behavior of short cracks in stress-relieved, precracked specimens was found to be strongly dependent on the precracking load condition. Particularly, when the final effective stress intensity range (ΔK
eff) during precracking exceeded the initial ΔK
eff of subsequent fatigue tests of the precracked specimens, the closure behavior of short cracks in precracked specimens was startlingly dissimilar to that of short cracks initiated in smooth specimens. This result implies that the short cracks in precracked specimens can not be always regarded as identical to normally initiated short cracks. However, if the stress intensity range (ΔK) during precracking does not exceed the initial ΔK of subsequent fatigue tests of precracked specimens, the closure behavior of short cracks in precracked specimens will be nearly identical to that of normally initiated short cracks in smooth specimens. The growth rates of short cracks in precracked specimens were well represented in terms of ΔK
eff as were those in smooth specimens. The stress relief annealing in vacuum was found to slightly decrease the material resistance to growth of short cracks.
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Hironobu NISITANI, Norio KAWAGOISHI
1985 Volume 51 Issue 471 Pages
2560-2563
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Plane bending fatigue tests of notched plate specimens are carried out to investigate the effect of a crack profile on the crack growth law. The growth rate of a through crack is expressed in the same form as the one of a surface crack; that is, under high stress level, dl/dN∝σ
nal (σ
a: stress amplitude, l: crack length), and under low stress level, dl/dN∝ΔK
m (ΔK: stress intensity factor). These parameters σ
nal and ΔK controlling the crack growth rate are available when σ
a/σ
s>0.6 and σ
a/σ
s>0.5 (σ
s: yield stress), respectively.
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Min Gun KIM, Kunihiro YAMADA, Takeshi KUNIO
1985 Volume 51 Issue 471 Pages
2564-2568
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The effects of room temperature aging treatment are discussed on the critical condition for the onset of growth of non-propagating cracks on 0.15% C low carbon steel, with special emphasis on the length of the critical non-propagating crack and on the crack opening displacement at the crack tip. It is found from the experimental analysis that the aging treatment of a fatigue precracked specimen for 30 days at room temperature introduced the closure of a crack tip of the pre-crack and the reduction of crack opening displacement at the wake of crack, together with an improvement in crack growth resistance of the microstructure. This may cause an increase in the endurance limit of the specimen, through the enhancement of effective stress for the onset of growth of the critical non-propagating crack.
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Hiroshi IIZUKA, Manabu TANAKA, Ohmi MIYAGAWA, Dai FUJISHIRO
1985 Volume 51 Issue 471 Pages
2569-2574
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The effect of grain-boundary reaction (GBR) on high-temperature low-cycle fatigue life was investigated for austenitic 21-4N heat-resisting steel at 973K. The grain-boundary was considerably serrated by GBR during aging. The high-temperature fatigue life was remarkably improved by the occurrence of GBR for fast-fast and slow-slow symmetrical triangular strain wave shapes. The fatigue life was not changed by GBR for the asymmetrical triangular wave shape. The longest fatigue life was observed on the specimen with GBR nodule was internally cracked by cyclic deformation. The improvement of fatigue life by a small amount of GBR was resulted from the retardation of brittle intergranular fracture by the serrated grain-boundary configuration.
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Yotaro MATSUO, Koichi KITAKAMI
1985 Volume 51 Issue 471 Pages
2575-2582
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Finnie et al. developed the statistical theory of fractured location which can estimate not only fracture stress but also fractured location. Some researchers analysed several problems using this theory and proved its validity. However, these studies are restricted to only one kind of fracture origin. In this work we have suggested a new theory combining the competing risk theory with the statistical theory of fractured location. Using this theory we derived the distributions of fractured location, corrected stress (a stress at the location of the fracture origin), the depth of the fracture good.
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Kazuro KAGEYAMA, Katsunobu NONAKA
1985 Volume 51 Issue 471 Pages
2583-2587
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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A method for an in-plane fracture toughness test for CFRP is proposed in this paper. A new SEN tension specimen and loading grip system are developed for extremely anisotropic materials, such as CFRP. A personal computer program is developed in order to calculate the effect of anisotropy on the stress intensity factor, K, of the SEN tension specimen. The program is used to calculate K
Q from the critical load at crack propagation. An a. c. electrical potential drop measuring system with a temperature compensation circuit is developed and applied to determine the crack initiation. Carbon/epoxy[0/90]laminates are used in the in-plane fracture toughness test. A procedure for the evaluation of fracture toughness, K
C, is proposed based on the relation between K
Q and the electrical potential drop at crack propagation.
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Kazuro KAGEYAMA, Takayuki KOBAYASHI, Masanori KIKUCHI, Hiroshi MIYAMOT ...
1985 Volume 51 Issue 471 Pages
2588-2593
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The sub-microscopic fracture processes of carbon/epoxy [0/90] laminates are analysed experimentally and numerically. The single edge notch (SEN) specimens are loaded to several levels of K
I, and the 3-dimensional crack growth behavior is investigated by using X-ray radiography. The 3-dimensional stress distribution in [0/90] laminates is calculated by the finite element method (FEM), and crack front singularities are measured by using the 3-dimensional j-integral. Before the applied load reaches K
C, it is observed that sub-cracks propagate parallel to fiber direction in each ply, but the finite element analysis of crack propagation represents the fact that the effects of the sub-crack growth on the stress of fiber direction ahead of the initial crack tip is not remarkable. K
cf and K
cm, which represent the fracture toughness values of fiber breaking and matrix cracking respectively, are obtained by the 3-dimensional FEM, and it is concluded that the fracture toughness K
C of [0/90] laminates can be evaluated well from K
cf and K
cm.
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Sotoaki KIDA, Juhachi ODA
1985 Volume 51 Issue 471 Pages
2594-2599
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The effects of mass, impact velocity, and geometry on fracture patterns produced by a concentrated impact loading on brittle variable section beams has been studied both experimentally and theoretically. The experiments were performed by impacting variable section beams made of plaster with a steel ball. The fracture behavior was explained using the theory of flexural motion with an impact-fracture criterion. It was found that the theory of an infinite plate, rather than the theory of a semi-infinite beam with a uniform section, can estimate very well the relation of impact velocity and the distance from the impact point to the crack initiation point. Moreover, the variations of fracture patterns on the impact velocity and mass were also considered qualitatively.
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Shun-ichi KAWANO, Shigetoshi SHIMIZU, Shin-ichi FUJITA
1985 Volume 51 Issue 471 Pages
2600-2604
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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This investigation presented an approach for estimating the energy which was absorbed during the penetration of a circular thin metal sheet by a conical punch, based on the J-integral R-curve approach to characterizing a material's resistance to fracture. The formula for the estimation of the total work done during the penetration was proposed by using the tear modulus, T. The penetration tests on the circular thin sheets of mild steel, whose thicknesses were 1.0, 2.1 and 3.1mm, and whose diameters were 450mm, were carried out at a quasi-statical speed using conical punches with punch angles of 30°and 45°. The effects of plate thickness and punch angle on the plate failure mode, the number of petals, the thickness directional strain ε
z and the total work done were investigated. The estimated values of the total work done by the proposed formula were found to be in fairly agreement with experimental results.
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Shigeyoshi OIWAKE, Setsuo MIURA
1985 Volume 51 Issue 471 Pages
2605-2610
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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This experiment has been undertaken to examine the relationship between the energy released from the movement of the hammer of the impact bending tester of the Charpy type and the stored energy in the fracture surface of the specimens in temperatures ranging from -90°C to 30°C. The specimens were slightly fatigued beforehand by bending in the same direction as the impact bending. The mechanism of the fracture of the specimens by impact forces has been clarified in the present study, after disseminating the information of the amount of energy accumulated in the tested specimens during course of time. It was understood that the prefatigued notched carbon steel specimens showed a strong terperature-dependence for fracture in low temperatures.
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Masao SHIBAHARA, Tadashi TAMURA
1985 Volume 51 Issue 471 Pages
2611-2614
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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Subsequent to previous reports, this paper is concerned with the dynamic fracture criterion and dynamic fracture behavior of a cracked cantilever, which is subjected to a transversal impact. Experiments were performed on four kinds of specimens of different sizes. By means of the dynamic photoelastic method using a high speed image converter camera, the change of the dynamic stress intensity factor and the crack propagation phenomenon were analysed. Moreover, the dynamic finite element method was used to analyse the dynamic stress intensity factor and the dynamic fracture behavior. The results showed that there was a trend toward a larger time delay for the dynamic stress intensity factor with an increasing crack length, compared with that for the incident stress. Also, they showed that experimental stresses for initiating crack propagation could not be explained simply from the static similar laws.
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Masahiro ICHIKAWA
1985 Volume 51 Issue 471 Pages
2615-2618
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The upper confidence limit P
f, r, for the probability of failure P
f=Pr(R<S) has been derived for the case where both the stress S and the strength R have normal distributions and their means and variances are unknown based on the assumption which is more practical than that in the previous paper. By making use of the table of the one-sided tolerance limit factor the normal distribution, P
f, r is obtained numerically. The result is useful in reliability analysis to take account of the fact that the true values of the distribution parameters are unknown and have to be estimated from the date of the finite sample sizes.
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Juhachi ODA, Masashi USHIROJI
1985 Volume 51 Issue 471 Pages
2619-2623
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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In this paper, FRP bonded structures, which are single lap joints subjected to a uniform load and L shape joints subjected to a bending moment, are analyzed numerically by the finite element method. In the method, the adhesive layer is assumed as the spring element transmitting only a shearing force. The stress distributions on the two joints change very much with the orientations of the reinforced fibers. If the orientation coincides with the longitudinal direction of plates, the maximum stresses in the adhesive layers of the two joints reach the minimum values. Moreover, the stress distribution on the single lap joint can be estimated by using the isotropic joint model with only the longitudinal Young's moduli of FRP plates. For the L shape joint, however, the stress distribution is very complicated and cannot be estimated by such a model.
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Hiroyuki TERADA, Tsuyoshi NAKAJIMA
1985 Volume 51 Issue 471 Pages
2624-2627
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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An analysis of the stress intensity factor is made for a crack vertically approaching the welding line in an infinite plate. The simple equations proposed by the author and others were employed in the analysis as the distribution function for the residual stress caused by welding. The effects of crack location, or the eccentricity, and the crack length on the stress intensity factor may be obtained not when the crack center coincides with welding line but when the crack front approximately reaches the welding line. For the better understanding of the behavior of a crack approaching the weldment, analysis was also carried out for a crack with various length but constant eccentricity. It was found that the stress intensity factor whips once, when the crack front go accross the welding bead.
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Toshio YOSHINO, Toshihisa OHTSUKA
1985 Volume 51 Issue 471 Pages
2628-2633
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The authors have previously worked on a method of microscopic 3-D analysis by FEM for plain weven fabric reinforced plastics. In the present investigation, it was proved that our method can be extended for a twill woven fabric one too. Through the present analysis, it was found that the highest value of maximum principal strain is generated in the matrix near the end of the transverse strand which just crosses over longitudinal one. From the present result on the transverse strand which just crosses over longitudinal one. From the present result on the elastic module and the previous one on the plain woven reinforced plastics by 3-D FEM analysis, it was clarified that the former has an advantage over the latter in a high Young's modulus net on the other hand, the former's Poisson's ratio is bigger than the latter's.
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Yoshinobu TANIGAWA, Tsuyoshi UEHIGASHI
1985 Volume 51 Issue 471 Pages
2634-2640
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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This paper is concerned with a transient thermal stress analysis of two-dimensional plane problems with orthotropic material properties under consideration of the effect of a heated moving boundary. In the theoretical development, a semi-infinite strip is treated. Assuming that the heated edge of a strip kept to a constant temperature moves with a constant velocity as a result of melting or freezing or freezing or some thermal and mechanical workings, temperature distributions are analyzed with aid of a moving coordinate system. Thereafter, the associate stress distributions are developed using with the Airy's stress function method. As an illustration, assuming that the heated boundary moves with a constant velocity, numerical calculations are carried out for several values of the anisotropic parameters of thermal and mechanical properties. These effects for the temperature and the associated stress distributions are examined.
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Keizou SAKURAI, Nobukazu ISHIHARA, Toshinori SUZUKI
1985 Volume 51 Issue 471 Pages
2641-2645
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The Hertz theory applies only when the compressive forces acting on two spheres in contact with one another are comparatively small, and the stresses produced therefrom remain within the yield point of the material. In most of the practical cases encounted in engineering, however, the compressive forces are so large that the Hertz conditions are not satisfied, and a partial or complete distribution of constant yield pressure results on the surface of contact. This has so far been verified experimentally by some investigators. To help numerically evaluate such a pressure distribution, one approximate analysis method is proposed, by means of which the relations between load and deformation either for the case of loading or unloading (increasing or decreasing compressive forces) can be established. For generality the variables, geometrical or physical, appearing in the expressions derived are given throughout in dimensionless form.
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Toshiaki HARA, Hirohiko OHISHI
1985 Volume 51 Issue 471 Pages
2646-2650
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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This paper is concerned with the applicability of the ultrasonic technique to the measurement of the interfacial stress between a metallic punch and some non-metallic plates. The characteristics of the ultrasonic wave due to the variation of the interfacial stress between a metal and polymers are presented graphically. The changes in the ultrasonic beam density due to spreading near the edge of the punch are then investigated, and the scattering characteristics of the wave are estimated on the basis of the variation of the echo height as the probe is moved. The behavior of the stress field of nonmetallic plates indented by the punch is depicted in plots of the interfacial stress distribution, and quantitative ultrasonic techniques for the determination of an interfacial stress in polymers are discussed.
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Akira TSURUSAKI, Juhachi ODA
1985 Volume 51 Issue 471 Pages
2651-2655
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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In order to determine the tensile strength of brittle materials, the indentation test (the so-called cube splitting test) has been used in the same way as the indirect tension test on cylindrical specimens. However this method has not been so well explored as the cylinder splitting test. In this paper, the validity of the indentation test was numerically and experimentally investigated in detail. Numerical analyses, adopting Mohr fracture criterion., the load distributing width of specimens and so on. As the result, a simple and effective method to evaluate the accurate tensile strength of brittle materials was practically established by considering several test conditions, particularly the load distributing width and the aspect ratio of specimens.
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Tsunenori OKADA, Kaoru AWAZU, Yoshiro IWAI
1985 Volume 51 Issue 471 Pages
2656-2662
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The relations between erosion pit initiation and impact loads produced by cavitation bubble collapses were studied in a magnetostrictive vibratory facility. The distributions of collapse pressures (impact loads) were measured by our developed method with a piezo electric sensor and were compared to the pit size distributions observed on the initial eroded surface of AL, Cu and mild steel. The number of larger impact load to form a pit is very small and those loads are estimated at 9.1N, 9.7N and 13.7N for the pit of 4μm in diameter of Al, Cu and mild steel, respectively.
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Masaichiro SEIKA, Yasuo NAGASE, Kikuo HOSONO, Tadataka OYAMA
1985 Volume 51 Issue 471 Pages
2663-2668
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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In the nickel electroplating method of stress analysis, a basal copper plating is indispensable when nickel is plated directly on a steel specimen. In this paper, when the acid copper plating deposited in a sulfate bath is utilized as the basal plating, effects of the current density and the thickness of the basal copper plating on the proper stress of the upper nickel plating are examined, and an optimum condition for the basal copper plating is obtained. From the results obtained in this paper, it is concluded that acid copper plating deposited in a sulfate bath can be used satisfactorily as the basal on in the nickel electroplating method.
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Yuji SUGITA
1985 Volume 51 Issue 471 Pages
2669-2674
Published: November 25, 1985
Released on J-STAGE: February 21, 2008
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The author has previously presented the static load-deflection relations of a toroidal shell subjected to axisymmetric compression between rigid plates and those of its outer half when subjected to lateral compression. In both these cases, the analytical method was based on the incremental Rayleigh-Ritz method. In this paper, the effects of compression angle and strain rate on the load-deflection relations of the toroidal shell are investigated for its use as a shock absorber for the radioactive material shipping cask which must keep its structural integrity even after accidental falls at any angle. Static compression tests have been carried out at four angles of compression, 10°, 20°, 50°, 90° and the applications of the preceding analytical method have been discussed. Dynamic compression tests have also been performed using the free-falling drop hammer. The results are compared with those in the static compression tests.
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