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Masateru OHNAMI, Masao SAKANE
1978 Volume 21 Issue 154 Pages
547-553
Published: 1978
Released on J-STAGE: February 15, 2008
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In the present study, the effect of strain-wave shapes on creep-fatigue interaction of a super alloy X-40 was studied by using four types of total strain range-controlled fatigue tests at 800°C in atmosphere. The four types of the wave shapes were (a) push-pull continuous low-cycle fatigue test, (b) low-cycle fatigue test with tensile hold-time in each cycle, (c) low-cycle fatigue test with compressive hold-time in each cycle and (d) low-cycle fatigue test with tensile hold-time in every four cycles. Number of cycles to fracture of the alloy tested under strain wave (c) is larger than that of (b) and it is not far less than that of (a). The fracture life under strain wave (d) is nearly equal to that under the wave (b) in the total strain range of 1.0 per cent, but the former life is much greater than that of the latter one in the total strain range of 0.5 per cent.
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Mitsuyuki KOBAYASHI, Masaru YAMAMOTO, Ohmi MIYAGAWA
1978 Volume 21 Issue 154 Pages
554-560
Published: 1978
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Effect of precipitation hardening on the rotary bending fatigue strength of an austenitic heat resisting steel was investigated at room temperature. It was concluded that strengthening processes such as precipitation hardening were effective only when fatigue cracks formed were associated with slip bands, but in the presence of structural inhomogeneity such as twin boundaries the stress concentrated readily there and the fatigue strength decreased in spite of a hardness increase. In this case the work hardened layer had an important role of making the structure homogeneous at surface and it could prevent a decrease in fatigue strength. In order to improve the fatigue strength it was most important to reduce the structural inhomogeneity as well as to harden.
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Teruaki FUJITA, Takashi SADAYASU, Eiichiro TSUCHIDA, Ichiro NAKAHARA
1978 Volume 21 Issue 154 Pages
561-565
Published: 1978
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This paper contains a three dimensional solution for the stresses around a hemispherical pit at a free surface of an elastic plate. At infinity the plate is subjected to all-around tension parallel to the free surface. In the analysis, the method of Boussinesq's two harmonic functions approach is used and these functions are expressed in simple forms of cylindrical and spherical harmonics. The boundary conditions both on the upper surface and at infinity are satisfied automatically, while the remaining boundary conditions on the lower surface and on the surface of the pit are satisfied with aid of the Hankel transform and relations between the cylindrical harmonics and the spherical ones. Numerical calculations are carried out for four different values of radius of the hemispherical pit.
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Toshiaki HARA, Toshikazu SHIBUYA, Takashi KOIZUMI, Ichiro NAKAHARA
1978 Volume 21 Issue 154 Pages
566-571
Published: 1978
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The solution is presented, within the classical theory of elasticity, for an asymmetric mixed boundary-value problem of the elastic half-space subjected to moment by an annular rigid punch. In the analysis the problem is reduced solving an infinite system of algebraic equations under the assumption that the normal stress on the contact region may be expressed as appropriate Fourier series. Numerical results are illustrated for the distribution of displacements and stresses.
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Hiroyuki MATSUMOTO, Ichiro NAKAHARA, Misao SEKIMOTO
1978 Volume 21 Issue 154 Pages
572-578
Published: 1978
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The rigid circular cylinder cemented on an elastic half-space is rotated impulsively through a small angle. The problem is solved by setting up an integral equation for the Laplace transform of the coefficient of the stress function. The inversion of the Laplace transform is carried out by using the numerical method. The numerical results are shown for the impulsive response of the elastic half-space such as the stress intensity factor and the torque.
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Hiroyuki MATSUMOTO, Ichiro NAKAHARA, Yasumasa MATSUOKA
1978 Volume 21 Issue 154 Pages
579-586
Published: 1978
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The problem of the collision of an elastic cylinder onto an elastic solid is studied theoretically and experimentally. The effects of the material constants and the contact area on the time history of the impact load are analyzed based on the dynamic theory of elasticity for the solid and on the one dimensional theory of wave propagation for the cylinder. It is shown that the theoretical predictions are in good agreement with the experimental results.
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Takeo UGA
1978 Volume 21 Issue 154 Pages
587-591
Published: 1978
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A special plate-shaped specimen with two symmetrical, straight air gaps in the center portion and a pair of holes for load chucks at the end is proposed, fabricated and examined for thermal-stress ratcheting. Effective portion of the specimen is divided into three bars by a couple of slender air gaps. Two side bars out of three are enveloped with special trace heaters. Testing is made by on-off cycling of the heaters under a constant steady membrane stress. When thermal loading is applied by heating, the middle bar becomes a cold element and the other side bars hot elements. Descriptions and characteristics of the specimen, the test procedures and typical results are presented.
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Toshitaka TAMANO, Samon YANAGIMOTO
1978 Volume 21 Issue 154 Pages
592-599
Published: 1978
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In our previous paper, a theoretical solution applicable to plate or strip rolling process without tension has been derived from Orowan's fundamental equations by making some mathematical approximations to them. This solution is effective for explaining the rolling characteristics especially in the range of mixed friction where the regions of slipping friction and sticking friction coexist on the contact arc with roll. In this paper, we extend this solution to the case where front and back tensions are applied, and theoretically examine the effect of tension on rolling phenomena under various states of friction, particularly in the range of mixed friction.
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Hiroshi ITO, Yoshihiro SENDA, Hideki FUJIMOTO
1978 Volume 21 Issue 154 Pages
600-608
Published: 1978
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This paper deals with the behavior of a load lifted by a mobile crane during boom hoisting, and during boom hoisting and lowering which are executed at the same time. The equations of motion are given in the form of Lagrange's equation, and the solutions are obtained by Runge-Kutta-Gill method. In experiments the rope tension was measured with load cells, and displacements of the load and the boom point were measured with cameras and sound-wave. In conclusion, the theoretical analysis is verified, since the theoretical values are in good accord with the experimental values.
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Hiroshi ITO, Yoshihiro SENDA, Hideki FUJIMOTO, Yoshio KATO
1978 Volume 21 Issue 154 Pages
609-617
Published: 1978
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In the design of mobile cranes, dynamic load factors are of great importance. These factors have been established as "criteria" empirically and conventionally in many countries buy have never been investigated theoretically. In addition, the recent variety and up-rating tendency of mobile cranes have led to the unsuitability of the factors. In this paper, we begin by setting up various simulation models of cranes, then proceed to the numerical analysis. Furthermore we try to establish formulas for dynamic load factors using multiple regression analysis. These approximate formulas are simple polynomials in which basic dimensions of crane are variables, and they are found satisfactory enough for any practical application.
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Katsuyoshi SUZUKI, Shin TAKAHASHI, Hiroshi ISHIYAMA
1978 Volume 21 Issue 154 Pages
618-627
Published: 1978
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The in-plane free vibrations of curved bars with constant cross section, of which center lines are some plane curves are investigated by neglecting the rotatory inertia and the shear deformation. A rigorous method for solving the equations of motion is presented. As numerical examples, the frequencies and the mode shapes are shown in graphs for symmetric arc bars with clamped ends having the center lines in the form of sine, catenary, hyperbola, parabola, cycloid and for an asymmetric elliptic arc bar with both ends clamped.
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Koki MIZOGUCHI, Shigeru KOMORI
1978 Volume 21 Issue 154 Pages
628-636
Published: 1978
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This paper deals with the vibration and the stability of a cylindrical shell conveying a compressible fluid taking into account an effect of the boundary layer of the fluid. Mizoguchi's shell theory is used and the compressible fluid is treated as an ideal gas. The frequencies of shell vibrations are obtained for several flow speeds ranging from 10m/sec to Mach 3 under two kinds of the mean static pressures of the fluid. From the results with the infinitely long pipeline the cases of periodical support may be obtained by means of some simple drawings as in the first author's previous paper. The instability is discussed based on an energy consideration of the shell and fluid.
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Hiroshi YAMAKAWA, Masahiko AMARI, Masashi KUNIHIRO, Kazue KAWASHIMA
1978 Volume 21 Issue 154 Pages
637-643
Published: 1978
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In the first report, there has been presented a general method of optimum design of structures in which natural frequencies are involved in objective functions and/or conditions of constraints. In the second report, the method are demonstrated in the problems of "type-1"(i.e. to find the optimum shapes of structures which gave maximum fundamental natural frequencies under specified total mass). The structural elements having 1-and 2-section-freedoms are taken as concrete objects, and numerical results obtained were discussed in detail from many points of view. In this report, we consider the basic problems of "type-1" vibrating beams which are subjected to axial forces as advanced numerical examples of the method presented in the first report. Many numerical results are demonstrated and also discussed in detail. Especially, it is necessary to pay attention to the buckling problems in the case of beams subjected to axial forces and columns with regard to their own weight.
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Isao TODA
1978 Volume 21 Issue 154 Pages
644-651
Published: 1978
Released on J-STAGE: February 15, 2008
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Transfer functions for bayonet-type heat exchangers are obtained in a simplified form available for computer programming. In the transfer functions, the liquid temperature responses are related to changes in flow rates of both tube- and shell-side fluids. Both frequency and step responses are calculated from the transfer functions, and the effects of flow directions on the dynamic behavior are examined. Experiments of frequency response are carried out, and the data are shown to be in good agreement with the theoretical results.
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Terukazu OTA, Takashi MURAKAMI
1978 Volume 21 Issue 154 Pages
652-655
Published: 1978
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A nonlinear theory is developed for an incompressible two-dimensional flow over an inclined flat plate hydrofoil with finite cavity in a solid wall tunnel. The wake model employed is Tulin's double spiral vortex model. The effects of the tunnel wall are evaluated upon the hydrofoil characteristics such as the lift and drag coefficients and the cavity streamline comparing with previous theoretical studies and also existing experimental data.
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Tamotsu IGARASHI
1978 Volume 21 Issue 154 Pages
656-664
Published: 1978
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Experimental investigations on the flow characteristics around a circular cylinder with a slit have been carried out. Flow visualization, how-wire measurements of the wake flow and the distributions of the static pressure coefficients around the cylinder have been made. The experiments were car-ried out in the Reynolds number region of 13800 to 52000 for two slit ratios of s/d=0.080 and 0.185. Three different typical flow patterns were found for the inclination of the slit β. For 0°≤β≤40°, the self-injection into the wake was observed. In this case, the base pressure rose and vortex formation region moved downstream. For 40°<β<60°, the effect of the slit was little. For 60°≤β≤90°, boundary layer suction was observed periodically with a period of the shed vortices. In this case, the base pressure coefficient dropped and the shedding frequency decreased.
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Toshio TANAKA, Eiichi TANAKA
1978 Volume 21 Issue 154 Pages
665-672
Published: 1978
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A study has been made of the attachment of a radial turbulent jet flow to an adjacent offset disc plate. Mean velocity and turbulence together with pressure distributions were measured, and the effects of diameter and width of nozzles, and also of distance of nozzle center plane from offset plate on flow pattern were investigated. Length and average negative pressure in the region of recirculating flow were examined. The results were compared with those obtained for two-dimensional attaching jet flow. An oil film flow visualizing technique was also applied to determination of the flow pattern, and the results were compared with those assumed from measured velocity and pressure distributions. Position of maximum value of maximum jet center velocity, and also agrees well with the position of jet attachment point obtained by the flow visualization.
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Yutaka MIYAKE, Kazuo JYOWO, Manabu IGUCHI
1978 Volume 21 Issue 154 Pages
673-680
Published: 1978
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A turbulent boundary layer on a flat plate with the mainstream containing vorticity and turbulence has been examined experimentally. The experiments were carried out in the region where the mainstream conditions were constant in the downstream direction. The velocity defect showed similar profiles in every section in each test run. An approximate analysis was made assuming an equilibrium flow and it turned out that this method of analysis useful to interpret the experimental results, which show that the turbulent mixing becomes more or less intensive due to the mainstream perturbations in consideration. The vorticity affects much the turbulence within the boundary layer.
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Susumu MURATA, Toru OGAWA, Isamu SHIMIZU, Kazuyoshi NISHIHARA, Kanjiro ...
1978 Volume 21 Issue 154 Pages
681-688
Published: 1978
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This paper concerns a theoretical and experimental study of cross flow fan with inner guide apparatus. Effects of fan geometry on the performance are investigated. Theoretically, the inner apparatus provides a shockless flow on the inner periphery of the impeller, which has an arbitrary inner blade angle. A series of experiments have been conducted using four types of impellers with different inner blade angles β and inner vanes, whose shapes are identical to theoretical stream lines. One apparatus designed with a single vane and an impeller of β
1=100°produced a high and stable performance curve sloping downwards to the flow rate.
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Shoji SUZUKI, Yoshio UGAI, Hideomi HARADA
1978 Volume 21 Issue 154 Pages
689-696
Published: 1978
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Low-pressure centrifugal fans often produce low-frequency discrete noise, when operating in partial discharge. In this study, an attempt was made to find the cause of low-frequency discrete noise, using various parameters, and as a result, it was demonstrated that the low-frequency noise was ascribable to the rotating stall. Comparative experiments with airfoil vanes and circular thin ones showed that the frequency of low-frequency noise due to the rotating stall was given by the equation fs = 0.72 ni, where n = rotating speed and i = number of cells and that the number of cells was variable depending on the operating point.
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Mitsukiyo MURAKAMI, Yukimasa OGURI, Hiroyuki KATO, Atuo SAKAIDA
1978 Volume 21 Issue 154 Pages
697-706
Published: 1978
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Effects of wall curvature inaccuracies on discharge coefficients of elbow flow meters are examined theoretically and experimentally. The flow is analyzed mathematically for a two-dimensional potential flow and the result is confirmed by experiments. If a commercial elbow is used as a flow meter, the error in the discharge coefficients resulting from the inaccuracies of curvature may be assumed to reach about 5 percent. Thus it can be elucidated that at least a part of scattering in the discharge coefficients appearing in the past investigations should be attributable to the wall curvature inaccuracies of elbows used.
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Shimpei MIYAKAWA
1978 Volume 21 Issue 154 Pages
707-713
Published: 1978
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Effect of flow force in a spool valve on frequency characteristics of a hydraulic system was investigated, both theoretically and experimentally, in a fundamental hydraulic circuit composed of a spool valve and hydraulic motor, which are affected by the hydraulic loss at a cylindrical damping choke in a pilot line. The result indicated that with an increasing g' (=flow force/spring force of the spool valve) the damping coefficient decreased and the resonance frequency of the spool valve became different from that of the motor, but at g' smaller than a certain value the amplitude of angular velocity of the hydraulic motor decreased even if the spool valve was resonating.
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Yutaka TANAKA, Yuzuru SHIMAMOTO, Toru NAGAI
1978 Volume 21 Issue 154 Pages
714-721
Published: 1978
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In this paper is proposed a calculating method for the simulation of oscillatory combustion state, and comparisons between estimation results and experimental ones are carried out. With respect to the effects of geometric dimensions of combustion system, and of fuel- and air-flow rate conditions on characteristics such as an amplitude of oscillation, its fluctuation, and a frequency, a theoretical analysis presents a correct estimation of the phenomena.
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Mikio FURUYAMA
1978 Volume 21 Issue 154 Pages
722-729
Published: 1978
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This paper report on a computative and experimental investigation for fuel supply characteristics of carburetor in which only an idle-system with two exit ports, that is, by-pass and idle ports is operated. The computated results have been found in good qualitative agreement with those obtained from the experiments. The investigations have revealed the effects of the geometries of idle-system on its characteristic curves and the reasons for the above effects. The results of the investigation will be used to clarify the problems of transition and interaction between idle-system and main-system.
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Sanae WADA, Hirotsugu HAYASHI, Shigeo HAISHI
1978 Volume 21 Issue 154 Pages
730-735
Published: 1978
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It is the purpose of this paper to predict an approximate theoretical solution for non-Newtonian problems of the elastohydrodynamic lubrication because such a theory is not established in a form suitable for application to this kind of fluids. The approximate analytical procedure in this paper is made possible by introducing the elastic deformation due to the film pressure in the inlet region between heavily loaded rotating cylinders into Grubin's approach. Pressure dependence of the viscosity and the nonlinearity of non-Newtonian fluids are measured by using a high pressure viscometer. The information obtained is useful to predict the theoretical film thickness of the elastohydrodynamic contact to compare with the experimental values. Experiment and theory are in approximate agreement over most of the range of the film thickness between two rotating cylinders.
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Hiroshi EDA, Kozo KISHI
1978 Volume 21 Issue 154 Pages
736-746
Published: 1978
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This paper describes basic and systematic estimation for the residual stress, hardness and structure of the ground surface layer of α·Fe-Fe
3C alloys with volume fraction of cementites ranging from 1.0 to 14.1%. Furthermore, we also investigated the relation of the residual stress, hardness and structure in surface layer and grindability factors. The main results obtained are as follows; 1) The residual stress of Fe
3C phase in ground surface layer is measured by a trial-made X-ray strain meter. 2) The residual stress ratio in the two phases σ
ic(Fe
3C)/σ
iF(σ·Fe)=4∼5 is obtained in the case of 10% Fe
3C or more. 3) With an increase in the grain size of Fe
3C (d^
-0) and Fe (d^
-) crystals, the fluctuating and depth values of residual stress distribution increase gradually. Furthermore, the residual stress of the lamellar cementite is larger as a whole when it is compared with that of the spheroidal cementite.
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Masanori YOSHIKAWA, Shigeru TAKANO, Toshio ASAEDA
1978 Volume 21 Issue 154 Pages
747-752
Published: 1978
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This investigation was carried out on the compressive strength of a truncated anvil as one of the basic studies on a piston-cylinder apparatus for high pressure. It is proved that the best taper angle to the horizontal of the truncated anvil to generate high pressure at the small face is 15°because the anvil suffers little deformation. It is also proved that the deformation of the conical face of a tungsten carbide anvil is much the same as the deformation of a tool steel anvil when the pressure is one and half times as large as the pressure applied on the tool steel anvil.
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Yasuo KASUGA, Shigeaki TSUTSUMI, Toshihiko MORI
1978 Volume 21 Issue 154 Pages
753-760
Published: 1978
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Behavior of metal which lies in the clearance zone and in its neighborhood has been investigated in the case when circular specimens are blanked by tools having circular contours. To the zones of interest, a particular visioplasticity and a strain gauge method are applied. In the circular blanking, materials in the neighboring zones can constrain radial metal flow into and/or out of the clearance zone, so that the flow changes markedly with the proceeding of the punch. The tool clearance affects the flow pattern during the process. It has been found that the time when the ultimate crack initiates depends on the discontinuity of average radial velocities of material across the product and the scrap sides.
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Komei FUJITA, Akira YOSHIDA
1978 Volume 21 Issue 154 Pages
761-767
Published: 1978
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In order to clarify the surface failure and the surface durability of surface hardened steel rollers, case-hardened and nitrided steel rollers having 60mm outside diameter were examined by a rolling contact fatigue testing machine. With case-hardened rollers, there is optimum case depth for surface durability. The surface durability of nitrided rollers spalling cracks initiate in case-hardened layer and with nitrided rollers at case-core boundary. At the locations where spalling cracks initiate, the amplitude of the ratio of share stress to Vickers hardness becomes maximum. The surface durability and rolling contact fatigue life of case-hardened and nitrided rollers can be calculated by using the equations for the relation between the relation between the maximum amplitude of this ratio and the number of cycles to surface failure.
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