The paper describes a supplementary investigation on the authors' former work concerning the notch effect in low-cycle fatigue of metals ( 1st Report on the same subject ), and presents another approach to the subject. The approach is such that an elastic-plastic analysis with the finite element method is made about a notched region of a member on the basis of the cyclic stress-strain relation of the material which is obtained under cyclic loading, and the peak value of strain range thus estimated at the notch is taken good as a measure for predicting the crack initiation life. In order to verify the validity of the proposed method in evaluating the notch effect on the low-cycle fatigue, calculations with the finite element method on several notched members, measurements of notch root strains under monotonic and cyclic loadings and low-cycle fatigue tests on smooth and notched specimens were performed. By the comparison of the calculations and tests, the proposed method for the elastic-plastic analysis and for the evaluation of the notch effect was verified to be valid.

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In the 1st and 2nd reports on the studies on impact fatigue, the authors had reported on the impact fatigue characteristics of the carbon steels that an impact fatigue failure occurred in the cycle range exceeding the critical number of stress cycles observe in the ordinary fatigue test and in the stress range below the ordinary fatigue limit, and that the impact fatigue failure occurred at a lower value of the inelastic strain amplitude than that observed at the stress level of the ordinary fatigue limit, and moreover, less cumulative hysteresis energy was needed for the impact fatigue failure than for the ordinary fatigue failure. In the study reported here, the investigations were made using pure aluminum and duralumin, and the following results were obtained : the impact fatigue characteristics are the same as those mentioned above in the case of pure aluminum, but, a little different strength behavior and a peculiar inelastic behavior were observed in the case of duralumin ; and the latter was discussed with the aid of a mechanical model.

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The mechanism of formation of striations on the fatigue fracture surface is considered from a crystallographical point of view for striations observed by scanning electron microscopy on a Type 316 stainless steel fractured by low-cycle fatigue at high temperatures. It is observed that striations change their directions abruptly and regularly at parallel lines which are considered to be twin boundaries. The directions of striations in relation to twin boundaries and the stereographic relation of the neighbouring fracture surfaces are obtained. Straight interstriation markings parallel to the main striations are sometimes observed. In some regions striations with sharp saw-toothed edges and saw-toothed interstriation markings are also observed. One part of these striations is considered to be formed by Pelloux's mechanism. The other part is considered to be formed by a mechanism that premised deformation zones consisting of cross slip planes in front of the crack.

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The main purpose of this paper is to make a study of anisotropy of fatigue limit and of the crack propagation property of a rolled steel plate by observing the fatigue process. A series of rotating bending fatigue tests were carried out by use of plain specimens and specimens with a small hole, cut out of a rolled steel plate. The main results obtained are as follows : 1) The fatigue limit of a plain specimen cut out in the rolling direction depends on the propagating condition of the microscopic nonpropagating cracks occurring along slip bands or grain boundaries, while that of a plain specimen cut out in the plate-thickness direction depends on the propagating condition of the ones occurring from inclusions. 2) Anisotropy of the crack propagating velocity of a specimen cut out in the plate-thickness direction is hardly observed under such a condition that only a single crack propagates preferentially, while it condition that only a single crack propagates preferentially, while it is remarkably observed under such a condition that the main crack propagates, combining the micro-cracks initiated from inclusions.

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There are many cases that a permanent deformations called plastic flow take place in the materials of severely heated parts of thermal engined and etc. caused by the ratcheting superposition of thermal and mechanical stress. In this paper, the ratcheting is first classified in various types of thermal load, and then, those elongation rates are theoretically analysed. Moreover, several experiments were performed in order to check whether the theoretical explanations were reasonable or not, using thin tubes which are heated rotationaly or alternatively from outside, while they are pulled in axial direction. Besides those, the existence of critical conditions for the plastic flow generation was also studied theoretically and experimentally. Recently, as ratchet problems are becoming the subject of wide interest, it is desirable that this study can be of any service to further investigations.

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The improvement of the press formability of a sheet metal has been performed by the following procedure. First, benetificial characteristics are sought from the data in the actual performance of the press forming, and then the sheet producing conditions which make these characteristics dominant are examined. In our approach, basic features of the deformation elements composed in the press forming are confirmed first, and then preparation of a new sheet which has the characteristics conforming to these features is aimed at. That is, improvement of the formability is tries by proposing the idea of an inhomogeneous sheet metal which has hardness change in the thickness direction to conform to the strain distribution of the bending. The inhomogeneous sheet is simply prepared by some mechanical treatment and the following results are confirmed in this experiment. (1) In bending, the strength of the bent portion is improved. (2) In deep drawing, the limiting drawing ratio is remarkably increased.

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An approximate method using a double trigonometric series for the bending of a plate with nonuniform thickness is proposed. The convergency of solutions with this method is examined to be satisfactory. Furthermore, simple approximate formulae to estimate the maximum deflection and surface stresses of the plate with the linearly varying thickness in one direction under uniform pressure are derived. The error of these formula for typical cases here treated is found to be less than 2 per cent.

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The turbulence characteristics of an opposed jet which is issued against a uniform airstream are studied experimentally. Measurement of turbulence intensities and Reynolds stress is performed by rotating a single hot-wire probe about its axis of symmetry and using a three point measuring technique. For measurement of high intensity turbulence a new method in which the Pitot tube method is coupled with the hot-wire method is devised and good results are obtained. Experimental results confirm the theoretical assumptions which the authors made in the previous paper.

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Using an actuator model, velocity and pressure distributions of a flow around a cross-flow impeller are derived, which are in good agreement with experimental results on impellers with radial blades. Under the assumption that the stability of an eccentric vortex in the radial direction inside an impeller is achieved when an input furnished to the flow by impeller-bladings balances with energy dissipation by fluid viscosity, the stability conditions are discussed. Critical Reynolds number of stability for an axisymmetric vortical flow is given as a function of eccentricity of vortex. Performance of a fan with a simple casing around an impeller is obtained by numerical computation and influences of several parameters on it are clarified. It is found that only one circumferential location of stability of a vortex to make input maximum exists for a given eccentricity.

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In this paper, the flow patterns in the blade passage of a radial inflow turbine are presented in three dimensions. The technique of tracer particles is developed in order to make three-dimensional analysis of a photograph of particles taken by means of the conventional double-flash illumination. The development is attained by the methods in which the diameters of the circles of diffusion of the picture of particles taken out of focus are measured, because the perspective distance can be estimated from them. The availability of this three-dimensional method is verified by the experiments; therefore, in three dimensions, the particle trajectories can be compared with the flow patterns predicted by the compressible inviscid theory. The results show in a radial portion that the trajectories are in fairly good agreement with the flow patterns under the condition of shock free entry, and that the secondary flow and the flow passing through the axial clearance are appreciably feeble. Further, the theory is inapplicable to the run of reduced speed of rotation.

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Experiments have been carried out to measure the thermal or electrical conductivity or suspensions composed of variously shaped particles dispersed in gelatin gel at volume fractions from 0 up to 0.6. On the basis of these measurements as well as the values previously published by other authors, the dependence of conductivity on the shape of suspended particles is discussed and some of explicit and theoretical expressions proposed up to data are evaluated. For the purpose or predicting the conductivity of suspensions the Bruggemann equation is most promising for spherical dispersion and the Fricke equation is more reliable than others for dispersion of which the shape is significantly different from a sphere, if the shape of suspended particles is well approximated to an ellipsoid.

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The P-V-T properties of fluorocarbon refrigerant R 13, i.e. trifluorochloromethane, were experimentally determined using a constant volume apparatus of 270cm³ approximately in its inner volume, which is useful in the ranges of temperatures from -120°C to -100°C and pressures up to 100 kgf/cm², as described in the present paper in detail. The present measurements for this substance were made with special attention to the neighbourhood of the saturation line in the range of temperatures from 0°C to 100°C with accuracies of ±0.010°C above 20°C and ±0.015°C below 20°C, in the range of pressures up to 100 kgf/cm² with accuracy of 0.014 kgf/cm² maximum and in the range of specific volumes from 0.95 cm³/g to 10 cm³/g with accuracy of 0.01 %. The present results show good agreement with those by Michels et al. and could be useful as the reference data for correlating the equation of state.

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Measurements of the saturation pressure of fluorocarbon refrigerant R 13 (CC1F₃) were conducted about 29 points using the P-V-T equipment described in the first report in the range of temperatures from -40°C to 28.7°C. An equation of the saturation pressure was formulated using these observed results and those by Riedel and by Albright et al. in the range of temperature above -140°C with a mean absolute deviation of ±0.040% concerning the present observed saturation pressure. Critical temperature was also determined with direct observation of the meniscuc using three different methods. Critical pressure was calculated from the equation of the saturation pressure at critical temperature. And also the critical specific volume was determined with Cailletet-Mathias law analyzing the P-V-T data described in the first report.

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The control of the burning rate is very important in a common diesel engine, and is also an important problem especially in a lower compression ratio diesel engine for further improving the noise emission, thermal efficiency etc. In this paper, for the purpose of controlling the initial burning rate, it was tried to investigate experimentally and theoretically the relationship between the intake air temperature and the initial burning rate. And the effects of the intake air temperature on engine performances, startability and No_x emission, were also examined. As to the burning rate, the initial maximum burning rate almost the same as the experimental one could be obtained by calculations using the evaporating theory of droplets and the thermal reaction theory. And the possibility and the extent of controlling the initial burning rate by an increase of the intake air temperature, were made clear.

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In order to fine the spring constant of connected parts in bolted joints, many experimental or theoretical researches have been done. But the theoretical and experimental results show a disagreement. As one of the reasons for this, is considered the deformation of a bolt-head which was included in the value regarded as the deformation of the connected parts. And the traditional theoretical researches have been done under the assumption that a uniformly distributed pressure is applied over the bearing surface. In this paper, using the point matching method coupling with the finite element method, a pressure distribution on the bearing surface is made clear as a contact problem of two elastic bodies, and then the deformation of the bolt-head and the connected parts under such a pressure distribution are analyzed and the spring constant are calculated. In addition, the spring constant is measured by experiment. According to the result, the value of the spring constant that was computed by taking account of the pressure distribution of the bearing surface, is not so different from the result under the assumption of a uniformly distributed pressure and Shibahara and other's theoretical value. When the deformation of the bolt-head is taken into account, the theoretical and experimental results show a fairly good agreement.

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The performance of worm gears is affected by the inclination of the contact line. In case of worm gears, the problem is that the contact lines of worm gears are nearly parallel to the sliding directions of the worm and the contact conditions are severe. But it has not been clear how much the inclination of the contact line affects the characteristics of friction. The authors, therefore, investigated quantitatively the relation between the performance and the contact line, and studied a method of designing and manufacturing worm gears with higher performance. First, the authors analyzed the relative motion of tooth surfaces of worm and wheel and made a test apparatus on which the contact conditions could be simulated considerably well. Next, experiments were conducted by using the apparatus which indicated pure effects of this factor. Further, the authors investigated into the performance of side worm gears, and tried to clarify the relation between the performance and the contact line.

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A flow-shop has n machine groups in series, where the k-th machine group (machine group k) consists of m_k parallel servers, each having the same constant processing-time s_k. Jobs enter the first machine group and pass through the machine groups, in order, on a first-come-first-served queuing basis and on an unlimited queuing basis. Every job passes all machine groups. For arbitrary input of jobs, this paper shows that the maximum queue length and the maximum waiting time at the machine group k exist if s_k-1/m_k-1>__=s_k/m_k. The maximum queue length and waiting time are calculated and the waiting space required between machine groups is theoretically determined. The filter effect of the machine group is also explained.

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