Bulletin of JSME
Online ISSN : 1881-1426
Print ISSN : 0021-3764
19 巻, 131 号
選択された号の論文の13件中1~13を表示しています
  • Seiich NISHIMURA, Katsuyuki TOKIMASA
    1976 年 19 巻 131 号 p. 459-468
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The phenomenon of wheel fracture is studied experimentally using a wheel testing machine and it is found that wheel fracture can be analyzed by the concept of linear fracture mechanics. The critical condition of wheel fracture is given by the circumferential residual tensile stress in the wheel rim, the depth of a crack in the wheel tread and fracture toughness of the wheel material. And further, the influence of wheel configuration and drag braking condition on the residual stress in the wheel is examined.
  • Kosuke NAGAYA, Yoshitaro HIRANO
    1976 年 19 巻 131 号 p. 469-476
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    This paper deals with a transient response problem of connected bars excited by the impact loads at rigid joints. In the analysis, an improved beam theory considering the effects of shearing deformation and rotatory inertia is applied to a bending motion of the bars. As a numerical example, we examine the dynamic response of an L-Bar to a step-function load to clarify the influence of the angle between its legs and slenderness ratio on the dynamic behaviors of the bar. The free vibration of the bar is also treated, and the results obtained from the improved theory are compared with those from the elementary one.
  • Yoji OKADA, Takashi NAKADA
    1976 年 19 巻 131 号 p. 477-484
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    In order to reduce the torsional vibration, usually passive dampers such as Vickers-Sandner damper have been applied. The major limitation of the passive vibration damper is the requirement for the absorber system parameters to be matched to those of the main structure. On the contrary, some types of active vibration dampers have been reported to be capable of effective operation over a wide range of varying conditions. This paper reports the results of an investigation on an electro-hydraulic active torsional vibration damper. The torsional vibration damper is subject to requirements that it rotates together with the total system or the attaching point in the system is sometimes restricted. In such a case, the resonant peak amplitude can be well damper out with the servo controller when the system parameters are chosen appropriately to the total vibration system.
  • Naomi KANDA, Seizo FUJII
    1976 年 19 巻 131 号 p. 485-491
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The characteristics of the optimalizing control system, which searches periodically the extremum by a correlation method, was analyzed in detail. The stability depends largely upon the initial condition as well as the parameters of the system. Corresponding to the initial value there exist the following three typical cases of response : (i) convergence to the optimum state, (ii) the oscillatory state, (iii) divergence. The conditions for the stability with respect to the initial value were obtained and the stable region was determined on the phase plane. The transient response for the displacement of the extremum point, and the influence of the noise upon the steady state error were studied. The integral of the error and the hunting loss were employed as the criteria, and the effect of the system parameters on the criteria was clarified. A design method based on the above results was proposed.
  • Kunihiko ICHIKAWA
    1976 年 19 巻 131 号 p. 492-496
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The author and an other have once presented a solving method of optimal control problem with discontinuity by determining optimal backward time trajectories. The method has the advantage that the optimal control law can be found, but it cannot be applied to high order systems because it requires the aid of diagram. The method presented in this paper solves the problem numerically with the aid of gradient and it can be applied to any high order systems.
  • Hitoshi NAKATANI, Shigeru MATSUMOTO, Yoshihiro MIYAI
    1976 年 19 巻 131 号 p. 497-504
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    For a subsonic flow, the surface pressure coefficients of a slender body of revolution, which is placed eccentrically in a tube, have been calculated by means of M2-expansion-method and as slender body in slender tube theory. The assumptions used in this calculation are as follows : (1) The fluid is inviscid. (2) The fluid is irrotational, as the eccentricity is small. The results obtained here are as follows : (1) With this method, analytic solutions can be easily obtained to a required higher order approximation. (2) When the uniform stream Mach number is 0.3 and the blockage ratio is 0.4, the absolute values of the surface pressure coefficient in the neighbourhood of the center cross section of the body are about 20 percent larger than those of incompressible flow. (3) As for the body shapes, that of parabolic spindle takes a larger value for the normal force coefficient than other body shapes.
  • Atsushi YAMAGUCHI
    1976 年 19 巻 131 号 p. 505-512
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The non-steady characteristics of orifices have been analyzed on the assumption that the free streamline forms an ellipse on the hodogram. The coefficient of contraction is greater than that fro steady flow during the period of acceleration, and smaller during the period of deceleration. In sinusoidal pulsating flow, the mean value tends to be slightly smaller than the steady flow value. The opposite is true for the coefficient of discharge, defined by the instantaneous flow rate and the pressure difference. The experimental results, in which the amplitude of the pulsating flow rate was less than 0.5 and frequency less than 50 Hz, agreed well with the theoretical calculations.
  • Masaru KIYA, Hiroshi SAKAMOTO, Mikio ARIE
    1976 年 19 巻 131 号 p. 513-522
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    A theoretical investigation is attempted on a separated flow past two-dimensional bluff bodies attached to a plane wall on which a turbulent boundary layer develops. The velocity profile in the turbulent boundary layer which would have been measured if the bluff body had been absent was replaced by a hypothetical inviscid shear flow of constant vorticity. This model admits analytical solutions and generates closed streamlines in front of the bluff bodies which are geometrically akin to the observed separation bubbles. Because of the lack of knowledge about the turbulent mixing along the edge of the separation bubbles, the present theory includes three or four constants which should be determined on the basis of the experimental information, the number of constants depending upon the shape of the body. For bluff bodies for which these constants can properly be estimated, theoretical pressure distributions agree well with experimental results. Flows around two typical shapes of bluff bodies, i.e. the normal plate and the semicircular projection are worked out in detail.
  • Masaru KIYA, Mikio ARIE
    1976 年 19 巻 131 号 p. 523-530
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    As a continuation to the preceding paper in which a general method of analysis of the separated flows past bluff bodies attached to a plane wall was presented within the framework of the free-streamline theory, the present paper applies the method to the cases of semielliptical projection and bluff bodies of arbitrary shapes. The theoretical pressure distribution on the wetted surface of the semielliptical projection is found to show good agreement with an experimental measurement. An analytical solution for arbitrary bluff bodies is obtained by assuming an inverse power series for mapping functions. Numerical calculations showed that reasonable pressure distributions could be obtained for a few profiles which were arbitrarily chosen.
  • Kozo KITOH
    1976 年 19 巻 131 号 p. 531-539
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The purpose of this paper is to clarify the relationship between the flow condition in the wall attachment amplifier and its characteristics. The flow patterns are observed in detail in cases of the flow divided by the splitter and the flow joined with a reversed flow from the output port of the non-attachment side, and the cause of the existence of these flow patterns and its effect on the characteristics of the amplifier are experimentally investigated. The flow models in the amplifier are proposed by referring to the experimental phenomena and the effect of load on the characteristics is theoretically investigated. The theoretical calculation on the characteristics agreed fairly well with the experimental results. It was made clear by the calculation that the flow pattern in the amplifier depends only on the load condition of the attachment side regardless of the load condition of the non-attachment side.
  • Tetsuo KOBORI
    1976 年 19 巻 131 号 p. 540-546
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    Critical heat flux data obtained for boiling water flow with a full-scale rod cluster of a water cooled reactor. The tests were performed on the effects of unknown parameters such as rod cluster eccentricity, spacer pitch and fuel configuration. From the experiment, the following conclusions are obtained : 1) The existence of low and high flow velocity burn-out regions was confirmed for rod cluster and the boundary between these two regions was almost the same as that for the round tube. 2) Rod cluster eccentricity has a marked effect on burn-out. An eccentricity of 0.6 mm lowers the critical heat flux by approximately 20%. 3) Burn-out is affected considerably by spacer pitch. If the spacer pitch is changed from 420 mm to 260 mm, critical heat flux increases by 38% maximum. 4) Critical heat flux can be increased by improvement of the fuel configuration. Test conditions were as follows ; pressure 70 kg/cm2, mass velocity 0.1∼10.7 × 106 kg/m2h, inlet subcooling 5∼200 kcal/kg, eccentricity 0∼1.0 mm and spacer pitch 260∼420mm.
  • Shinsuke ONO, Morio TSUGE, Mamoru KURUSU, Ichiro FUKUE
    1976 年 19 巻 131 号 p. 547-554
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    The turbulent flame propagation in a closed vessel is different from that of the burner flame with a steady constant flow in respect of fluctuation of flow component considered the main flow. In the flow field of this kind, as the flame front becomes very irregular, it is difficult to define the burning velocity corresponding to the space displacement of the apparent flame front. Defining the pressure increasing rate as burning rate, the effects of intensity and scale of turbulence on this burning rate in the combustion vessel are investigated with a recirculating jet flow through four perforated plates. From observations of flames and measurements of pressure rise in the vessel, it may be concluded that the reaction zone of turbulent flame diffuses to a considerable depth from the apparent flame surface and the scale of turbulence accelerates or retards the burning rate on account of instability of flame front.
  • Yotaro HATAMURA, Kenji CHIJIIWA
    1976 年 19 巻 131 号 p. 555-563
    発行日: 1976年
    公開日: 2008/02/15
    ジャーナル フリー
    Deformation and distribution of internal stresses in soil cutting are analyzed by experiment. The variable parameters are kinds of soils (dry quartz sand and plastic loam) and cutting conditions (cutting angle, cutting depth of cut and cutting speed). Sand always shows shear type of chip, and loam generally shows flow type. In both kinds of soils, a flat shear-plane appears. And the angle of shear-plane is smaller as the cutting angle increases. The distribution of internal stresses in soil is measured by internal stress cells. Its idealized pattern is as follows. The maximum principal stress trajectories (compressive) issue in parallel from the surface of cutting blade. Only the trajectories which issue from the cutting edge diverge abruptly. The minimum principal stress in front and lower parts of cutting edge is negative (tensile) under certain circumstances. Many kinds of cutting phenomena and important things for earth-moving machines are explanied from the conception of internal stress.
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