In this study, the effect of aging treatment on the fatigue crack propagation of 18% Ni maraging steel sheets was investigated. Main results are summarized as follows. An exponential relation holds between the crack propagation rate and the stress intensity factor range for the specimens heat-treated under each condition, and no significant difference in the values m and C is observed among the specimens heat-treated under various conditions involving the solution annealing. This means that aging treatment has no favourable effect to retard the fatigue crack propagation, even if the static strength of this steel is exceedingly elevated by the aging treatment. Although the fatigue strength is increased by aging treatment, the degree of increase depends upon the loading level and the aging condition. Namely, the underaging treatment is more preferable when this material is subjected to high cycle fatigue load.

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This paper deals with the axially symmetric torsion of a hollow cylinder with an external crack. The mixed boundary value problem is reduced to dual series equations. These equations are shown to be equivalent to an infinite system of simultaneous equations. Numerical results are presented for stresses, displacement and stress intensity factors.

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To investigate the compressive strength of polycrystalline zinc, constant strain rate and temperature tests and strain rate and temperature change tests were carried out. The ranges of the strain rate and the temperature of the former tests are from 10^-4/s to 7×10²/s and from -195°C to 100°C, respectively, and those of the latter are from 10^-4/s to 10^-3/s and from -195°C to 200°C, respectively. The effects of the temperature and the strain rate upon the strength of polycrystalline zinc are clarified. And, in the static strain rate range, the behaviours at high and low temperatures are interpreted in connection with the thermally activated mechanisms.

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The purpose of this paper is to develop a general method for optimum design of framed structures with regard to their elastic buckling behavior. In the method proposed here, the finite element method is used for computing the buckling load and Rosen's gradient projection method for optimization technique. To illustrate the wide applicability of this method, some examples of columns and plane portal frames are considered as the problems of finding the optimum shapes to maximize buckling loads for given structural mass and gross geometries. The treated examples contain several basic problems of columns for which exact solutions are known or available, and the corresponding present solutions are compared and found to be in fairly good agreement with them. As for newly treated examples of columns and frameworks, it also seems that reasonable solutions are obtained by proposed method.

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The moire method by use of diffraction beams is effective for the measurement of strain components. However, errors are caused by nonuniformity in thickness of film used as specimen gratings, unevenness of surface of mirrors, aberration in lenses, etc. in this paper three methods are proposed, by which these errors are compensated. First, "the looped path method" is discribed. In this method two beams which are to produce an interference pattern pass the same looped path, but in opposite directions to each other, thus the above mentioned errors are compensated. Secondly, an optical system proposed by Sciammarella(1967) is applied to the shifting method, and it is found that those errors can be largely reduced by adjusting an optical apparatus precisely. Thirdly, the double exposure method is described, in which the errors are compensated and sensitivity of measurement is doubled.

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The effects of the fluid viscosity on the unsteady forces on cascade blades are investigated based on a linearized Navier-Stokes equation on the assumption that the perturbations are small. Also the sinusoidal dissipating gusts are introduced on the same assumption and the lift and drag response of the cascades to the flow and the forces on the up and downwards vibrating blades are calculated. It is found that the viscosity of the fluid works so as to enlarge the amplitude of the unsteady forces but it has not so much effects on the phase of the lifts.

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Some experimental and theoretical studies of performances of rotating cascades operating under the radial-distortions are shown. The transmission of the distorted velocity profiles through the cascades, changes in characteristic curves and aerodynamic loading on the blade elements are obtained experimentally, and some discussions of the criterion of the onset of stall in the rotating cascades are made. The flow fields near the rotating cascades are analyzed by stream-line curvature method and the results are compared with the experimental ones. The rotating cascades have effects to attenuate the distorted velocity profile both at the design point and off- design points. The rotating cascades operate stable even when the aerodynamic loading near the root exceeds the stall limit of the two-dimensional cascades. The stall limit of the rotating cascade is determined by the equivalent diffusion ratio at a specific radius near the tip. The analytical results of transmission of the distorted velocity profiles through the rotating cascades, changes in the aerodynamic loading and stall limits agree with the experimental ones with sufficient accuracy.

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It was found for reattachment jets having large offset ratios that an agreement if good between the experimental results and the results of the approximated calculations obtained by using the solutions of a two-dimensional jet. But flows having rather small offset ratios show different values from the results of calculation. Existence of similarity in the reattachment jet flows having large offset ratios can be well expressed by introducing an appropriate parameter which represents a bubble pressure. Experiments also show that the behaviours of a two-dimensional reattachment jet flow are independent of Reynolds number, but the behaviours of a reattachment jet flow are dependent on Reynolds number in the case of three-dimensional flows having small aspect ratios.

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Surge pressure in a liquid conduit is often amplified extremely in the presence of trapped air or gases. In this paper the hydraulic transients in such cases were investigated, and on the basis of the results a method of absorption for surge pressure by means of an air chamber at the downstream end of conduit having a nozzle was studied. An appropriate arrangement of values of parameters in the presence of trapped air or gases absorbs the surge pressure most effectively.

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Pump control with a variable displacement type piston pump is mainly adopted for hydrostatic transmission of a relative large power. In this paper, the characteristics of servo type displacement control mechanisms used in a swash plate type and a bent-axis type piston pump are analyzed theoretically and experimentally. The calculated values by the non-linear theory coincide well with the test data. Effects of the parameters on the stability, the speed of response and so on are also discussed for general utility to design purposes.

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The performance of a turbomolecular pump in the transition and slip flow regimes is studied theoretically with the following two new assumptions about intermolecular collision. (1) The molecular number density is uniform in the passage of a blade row regardless of location. (2) In the process of intermolecular collision, molecules entirely lose their memory about the direction in which they have been moving before collision. Then, the theoretical results are verified by the experiments on several rotors with various geometrical dimensions. The theoretical results show good agreement with the experimental ones, and it is confirmed that the theory can be applied to a wide pressure range from free molecule to slip flow regime.

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Conditions for the occurrence of jumping instabilities of a float of float-area-type flow meters when employing the float without a stabilizer were experimentally studied. In this report, firstly, the limiting frequencies for the occurrence of jumping instabilities of the float were found by vibrating the float-area-type flow meter horizontally by means of a vibrating machine. Secondly, in order to obtain the natural frequency of the rotational vibrations of the float, a vibration-model of the float was proposed and the natural frequency of the float was obtained when the position of the centre of gravity of the float was shifted. Thirdly, the cause for jumping instabilities of the float was proved to be the resonance between the above mentioned limiting frequency and the natural frequency of the rotational vibration of the float around its centre of gravity.

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The purpose of our work is to solve various problems concerning working liquid motion which frequently arises in horizontal agitated thin film evaporators. Our previous paper reported an experimental investigation on the flow pattern in an evaporator using water at room temperature as working liquid. In this work aqueous glycerine in various concentrations is used as the working liquid to study the effect of viscosity on the flow pattern. We systematically study the effects of the liquid volumetric flow rate and of the rotational speed of wiping blade on the profile of wiped liquid fillets, the residence time in the apparatus, the axial dispersion and the power consumption. The results are correlated in non-dimensional form.

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The limits of flame propagation were measured in turbulent flow of homogeneous propane-oxygen-nitrogen mixtures. The inflammable range of equivalence ratios became narrower with an increase of turbulence intensity. The criterion for flame extinction due to turbulence was investigated. As a result, a linear relation was found at each of the lean and rich limits between the characteristic velocity of turbulent gas motion and the characteristic rate of chemical reaction in the laminar flame zone. It is concluded that flames are disintegrated into small flame-lets by strong turbulence and then extinguished owing to heat loss.

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A velocimeter constructed is composed of detectors and analog computing circuits through which the signals from detectors are directly converted to necessary values. The detectors have a thermocouple, static-and total-pressure probes respectively connected to condenser microphones and a differential pressure meter. With this constitution this velocimeter revealed its performance to be in the same level as a hot-wire velocimeter for a flameless field and provided more accurate turbulence degree in a combustion field than the earlier methods based on the measurement of only pressure variation. Through the application for an open diffusion flame, it was shown that the time constant of thermocouple can be estimated from Nusselt's number equation by Ahmad in combination with the signals obtained, and further that the correlation between temperature and velocity fluctuations becomes negative at the inside of maximum temperature location and positive at its outside.

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Both mass exchange processed between the recirculation zone and the outer flows (mixture and parallel air flow) have been studied regarding the mixing process as complete mixing and applying the results in our previous report of this study to the exchange processes. Each mass exchange and exchange velocity could be obtained from flow rates and the residence time. Measurements of the residence time for cold flow using the tracer method have been made in different burners of 8 mm i.d. with rims of thickness between 3 and 7 mm, and a successful dimensionless group could be found for the residence time. The characteristics of each mass exchange are discussed in terms of these results.

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Transmissibilities for single-loop spatial mechanisms are expressed quantitatively, and a guide for designing mechanisms with sufficient movability is suggested by considering the flow of power. One of the former transmission indices is improved with respect to its application. Then two methods for designing the mechanisms with sufficient movability are suggested : one is to synthesize the mechanism considering the above transmission index, and the other is controlling the low of power by attaching supplementary mechanisms. Such methods are applied to a spatial path-generating mechanism, and the relationships among the transmission index, power and the movability are investigated theoretically and experimentally.

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With regard to the bolts tightened over their yield point and subjected to the tensile load, the relation between the load and the residual bolt clamping force after unloading as theoretically analyzed, and a static bolt loosening test was carried out. It was verified that the theoretical results coincide very well with the results of experiments. And under the same condition a fatigue test was carried out with the measurement of the bolt clamping force, and the following results were obtained : (1) Except the loss in the initial stage, there is no loss of the clamping force. (2) With an increase of the initial clamping force, the residual clamping force and also the bolt fatigue life increase. So, judging from the above results, the tightening of bolts over their yield point has an advantage over the tightening of bolts below their yield point.

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In designing a bolted joint it is important to find the ratio of an increment of an axial force produced in a bolt to a load applied to an assembly, that is the force ratio. In previous paper, the tensile spring constant K_pt for the clamped part is introduced when a load is applied on the outer circumference of clamped parts and the force ratio is calculated by using K_pt. In this paper, the similar method is applied to calculation of the force ratio of flanged connections. Moreover, the bending moment produced in the bolt corresponding to the applied load is analysed. In order to verify these theoretical analyses, an experiment if carried out. The obtained results are as follows. (1) The theoretical values show a fairly good agreement with experimental ones. (2) In evaluation of sealing effect of flanged connections the raised face joints are more effective than the flat face joints.

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The authors produced experimentally a pitch tester for internal gears. In this tester, the conventional detector and the indicator of the external gear tester are utilized and a holding and fixing device of internal gears is mainly devised. It is shown by measuring test that the measuring accuracy and the reproducibility of the observed values of pitch are sufficient for practical use. Moreover, the influences of mechanical errors on the value of cumulative pitch error are discussed by the method of statistical analysis and numerical examples. Sufficient practicality of the tester is also shown theoretically and numerically by the analysis and the examples.

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In this paper, effects of bulk oil temperature and sliding velocity on the scoring phenomena of non-EP mineral oils were examined by a Shell type Four Ball Machine under the conditions that new steel balls were used for each load step and the machine was operated in 60 seconds after loading. The results obtained are summarized as follows : (1) Lubrication state of contact surface at last non-seizure load and the process of scoring at initial seizure load are affected by bulk oil temperature and in higher sliding velocity range, it is difficult to evaluate the scoring resistance of boundary lubricating film. Therefore, in the evaluation of scoring resistance of lubricating oil, attention must be paid to these points. (2) There is a correlation between the scoring resistance of boundary lubricating film and the maximum contact surface temperature except in the region of lower sliding velocity.

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In this paper, for two kinds of non-EP mineral oils, the effects of lubricating method, operating time and sliding velocity on initial seizure load were examined by step-load method using a Shell type Four Ball Machine, and the relation between the thermal strength of boundary lubricating film and the maximum contact surface temperature was clarified. The results obtained are summarized as follows : (1) There is only a negligible difference in maximum contact surface temperature (T_cmax)_s at scoring between the results in 5 seconds test and the results in 300 seconds test. (2) Without regard to lubricating method and operating time, (T_cmax)_s increases with an increase in sliding velocity, and in the sliding velocity range higher than 35 or 46 cm/s, (T_cmax)_s is nearly constant. (3) In 300 seconds test, a bulk temperature rise in steel balls has great effect on (T_cmax)_s.

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