The general steady-state dynamic boundary value problems of elastic bodies with cracks are formulated in the forms of the integro-differential equations. In particular, the equations for plane problems are worked out in detail. Several numerical calculations are carried out and stress intensity factors are obtained for the cases of plane harmonic waves being incident on two Griffith cracks in an infinite body.

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The stress concentration problem in the linear, couple-stress theory is treated for a circular cylinder with arc-shaped annular groove etc. under uniaxial tension. The solution is the "indirect fictitious-boundary integral method", which is expanded to solve the problems in the couple-stress theory. In this method, the unknown vector density functions, corresponding to concentrated forces and couples distributed over a fictitious-boundary supposed in an infinite medium, are determined so as to satisfy the requirements on a real-boundary. After all, the problem is reduced to solving Fredholm type integral equations.

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In an elastic contact between two uneven surfaces, elastic bodies smoothly contact with each other along the inner and the outer contact circumferences, and the circumferences shrink with an increasing applied force. We can regard the projection as a parabolic one in the case of small projection. So we analyze the three-dimensional elastic contact problem of an elastic half-space pressed onto a rigid base with a smooth parabolic projection and obtain the surface displacements and the contact stresses.

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If a flow enters an axially rotating pipe, it receives a tangential component of velocity from the moving wall, and the flow pattern and hydraulic loss suffer a change according to the ratio of the rotational speed to the through flow velocity. A flow laminarization is set up by an increase in the rotational speed of the pipe if the flow in the pipe is initially turbulent, and a flow destabilization is brought conversely about if the flow is initially laminar. Velocity distributions and friction coefficient in the fully developed region of the pipe were calculated by using a modified mixing length theory, and the results were compared with those by the experiments.

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A steady viscous flow through a two-dimensional, infinite channel consisting of an uneven wall and a plane wall is theoretically investigated under a given pressure gradient. The profile of the uneven wall is assumed to be periodic in the direction of the mean flow. A systematic expansion procedure is developed for the case where the ratio of the mean channel width to the period of the uneven wall, k, is small. An approximate solution is obtained up to the order of k² . As a result, the flow rate is explicitly found as a function of the profile of the uneven wall, k and the Reynolds number. The unevenness of the wall always decreases the flow rate in proportion to k² . The inertia effect on the flow rate first arises from the second order of k. The flow rate and the stream line are concretely obtained for the case of a sinusoidal wall. The approximate solutions show in good agreement with the solutions obtained by a numerical calculation.

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Detailed measurements of the turbulent quantities such as the turbulent intensity components and Reynolds shear stress in the cruciform circular cylinder wake have been made, in order to examine the similarity profile of the turbulent quantities and the streamwise growth of the turbulent flow field. Experimental results are summarized as follows : For the far downstream region, the decay rate of turbulent velocity scales is close to that of the mean velocity scale, and the profiles of three-components of turbulent intensity and Reynolds shear stress are similar. In the vicinity of a corner, a distortion due to secondary flows is observed on the contours of the turbulent quantities. Reynolds number based on the velocity scale U_d0 and the length scale L_X is constant and therefore the present turbulent wake remains steady.

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The drag forces of circular cylinders of infinite or finite span are examined in both Newtonian fluids and dilute polymer solutions. Using some circular cylinders with different ratios of length(l) to diameter(d), the drag forces in the Re range of 1 to 5×10⁴ and the pressure distributions in the Re range of 1.7×10⁴ to 5×10⁴ are measured. The results make it clear that (l) the drag forces decrease at R_e< 20 and increase at R_e> 20 with an increase of l/d, (2) the drag forces for dilute polymer solutions reduce more than those for Newtonian fluids at R_e< 1×10⁸.

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This paper is concerned with the rolling piston type rotary compressor for the air conditioner. The rotary compressor, as well as the reciprocating compressor, is one of the positive displacement compressors and has clearance volume of discharge port. But the influence of clearance volume on the performance of the rotary compressor is not equal to that to the reciprocating compressor. We analysed a reverse flow of suction gas through a suction opening caused by the re-expansion of high pressure gas in clearance volume taking account of throttling effects of suction and discharge openings. We investigated influences of operating conditions and dimensional parameters on volumetric efficinecy. Also we estimated compressor work using p-V diagram. It was made clear that clearance volume of the rotary compressor hardly decreases volumetric efficiency but increases compressor work in contrast with that of reciprocating compressor. Theoretical results are in good agreement with experimental results.

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The authors showed experimentally in what manner the local heat transfer coefficient is affected by the pitch ratio P and the offset ratio H when circular cylinders (blockage ratio R/L =0.4) are set in a staggered arrangement in a parallel plate duct in order to augment heat transfer from the plates. The distribution of local heat transfer coefficients depends on the flow pattern downstream of the cylinder which is influenced by the presence or absence of vortex shedding. The degree of augmentation is also analysed, taking account of pressure loss. In the low-Reynolds number turbulent regime, η, which is the ratio of the average heat transfer for the present system to that for a smooth duct under the condition of equivalent pumping power, is larger than unity at P=4.

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Forced convection film boiling heat transfer from a horizontal cylinder to a subcooled liquid cross-flowing upward is analysed based on the two-phase boundary-layer theory. Numerical solution of the conservation equations is determined for subcooled water, ethanol and hexane under the atmospheric pressure by the method similar to that of the first report for saturated liquid. The velocity profile, the separation point in the vapor film, the thickness of the boundary-layer and the average Nusselt number are discussed in the same manner as in the previous report and the effects of the subcooling and the approaching velocity on them are also examined. The calculated results on heat transfer are compared with the experimental data.

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This paper presents theoretical and experimental studies on the expansion cavity type mufflers with mean flow. It is shown in this paper that the inlet part of the tail pipe is a point of the largest flow noise generation inside the cavity of the muffler and a very large air flow noise is generated when a jet stream from the inlet pipe directly impacts the tail pipe.

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A mathematical model of a spray combustion in direct-injection diesel engines has been developed to predict engine performance, thermal efficiency and pollutant emissions. Injected fuel spray was divided into many small packages. Gas and fuel droplet temperatures and evaporated mass of fuel in each package were computed. In considering the complete air-fuel jet mixing process and temperature in each package, the model also enabled subsequent spatial and temporal history of burning rate, local temperature and air-fuel ratio to be calculated.

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An algorithm for predicting heat release rate and pollutant emission in direct injection diesel engine has been developed according to the mathematical model mentioned in the first report. Predictions made with the simulation have been compared with the data on a single-cylinder engine over a range of engine speeds, injection timings and swirl ratios. Predicted pressure diagram, and NO and soot emissions showed acceptable quantitative agreement with the data. A parametric study of the effect of variations in load, speed, injection rate, injection timing, swirl ratio and droplet size is then carried out.

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A mathematical method for obtaining the optimum values for a direct injection diesel engine design is developed using a system theory which is called "The Method of System-Model Transformation". Optimum values of the design and operating parameters, such as : number of nozzle holes, diameter of nozzle holes, diameter of toroidal, swirl ratio, clearance volume, injection timing, injection duration, closing timing of the intake valve and opening timing of the exhaust valve, are obtained for the minimum value of performance index which represents engine power, fuel consumption, nitric oxide emissions and soot masses.

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Two methods are proposed to analyze the damped vibration of mechanical structures by a reduced impedance methods (RIM), when a modal damping ratio or a frequency spectrum of the damping coefficient is given. First, modal damping ratios of some simple specimens are obtained experimentally by the technique of curve fitting the authors proposed. Next, the frequency spectra of response of the damped vibration are analyzed by the real RIM with the modal damping ratios. The same kind of analysis is performed by the complex RIM. Both of the analytical results by the above two methods agree well with the experimental ones. It is clear that the present two analytical methods by RIM is especially useful for predicting peak value of response curve at resonant frequency of the forced vibration.

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A multiple reduced impedance method (MRIM) is proposed as an advanced type of the reduced impedance method (RIM) for analyzing the vibration of a mechanical structure so complex that the usual methods, for example the finite element method, can not be applied directly on it. The natural frequency, the natural mode and the dynamic response of the supporting base of a diesel generator package are analyzed by MRIM. The analytical results by MRIM are compared with the analytical results by RIM and the experimental results. These three results agree well with one another. It is clear that the vibration of a complex structure can be analyzed by MRIM with less calculation time and with smaller memory storage than by RIM.

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Acoustic oscillations induced by a premixed flame in a pipe have been studied analytically and experimentally in comparison with the gauze tones which have been reported in the previous papers. The flame-induced oscillations may most possibly be generated when the dimensionless current velocity in the pipe is around unity as in the case of the gauze tones. The ratio of the reaction rate to the frequency is another important parameter indicating the possibility of oscillation growth by the flame, and when the ratio is small the oscillation cannot grow. The relation between the upper frequency limit of the oscillations generated and the current velocity in the pipe has been examined experimentally, and it agrees well with the analytical result. The calculated amount of energy supply can be supposed to coincide with the measured energy dissipation considering the inaccuracy of the experiment and the assumptions used in the analysis.

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A new torsional dynamic vibration absorber is proposed, consisting of a circular conducting plate and four cylindrical rare-earth magnets of which magnetic energy is extremely strong, and its absorbing characteristics is investigated experimentally and theoretically. First, the magnetic torsional stiffness between two magnets is analyzed theoretically, and the magnetic damping characteristics by the relative motion between the magnets and the conductor is investigated experimentally. Second, a solution of the steady-state vibration response is derived from the equation of motion with the term of the nonlinear magnetic torsional force, and the criterion of its stability is obtained. Subsequently, the experimental results about the optimum absorbing effect are presented.

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In designing a bolted joint, it is important to estimate the ratio of a bolt axial force to a load when a load is applied on an assembly, that is the force ratio. In this paper, in order to establish a simple method to calculate the force ratio of general bolted joints, the force ratio of T-flange is discussed. At first, in order to analyse more exactly, the T-flange is replaced by a finite strip. In the next place, in order to calculate simply, the T-flange is replaced by a beam on an elastic foundation. Moreover a bending moment is introduced in the bolt when the load is applied. In order to analyse this bending moment, a calculation method is proposed by defining newly the bending compliance of T-flanges and bolts. Then, to verify these analyses, experiments are carried out. The analyses are in a fairly good agreement with the experiments.

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Adjusting methods and the types of the outputs of some kinds of planar adjustable mechanisms are investigated, and optimum syntheses of such mechanisms are carried out. In the part 1, the path generators are studied, in which the adjusting methods and the types of the outputs are classified and planar 4-link and multi-link mechanisms are synthesized by considering the pressure angles and the ratios of link lengths. In the mechanisms which generate the ideal straight line and L-path, as examples, the relationships among the number of links, the number and kinds of the adjustable parameters, and the structural errors are analyzed.

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An efficient FEM application method is developed for a model which is the ensemble of elements of the same shape as gear teeth. Using this method, influences of chordal tooth thickness at the critical section of tooth, radius of curvature of fillet and rim thickness of thin-rimmed gear on the tooth fillet and root stresses are investigated. Summing up a lot of FEM calculated results, a set of approximation formulae is derived for the calculation of tooth fillet and root stresses of a thin-rimmed gear. A comparison of the measured tooth fillet stresses, FEM calculated values and the values from these approximation formulae has shown good agreement. These approximation formulae will therefore contribute to the strength calculation of a thin-rimmed gear.

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A method has been proposed by which a variety of actual cutting edge forms in cutting can be estimated from the information obtained with the observation of longitudinal section of chips only, and graphs illustrated by this method are presented. The formulas by which the actual rake angle in cutting can be calculated with the lattice pattern or the fibrous structure in the work deformed are induced. By applying these methods, the shape of built-up edge, the actual edge of restricted tool, in cutting, and so forth have been determined. And then, experiments have been carried out to substantiate these methods. The results coincide with the theory.

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A dynamometer used to support the cutting tool or fixed on the machine tool should have compactness, high sensitivity and high stiffness. The parallel-beam dynamometer is better than any other one in this respect, but it is not easy to manufacuture. So a dynamometer with a circular hole is newly being developed by applying the structure of parallel beams, and a small three-component dynamometer has been manufactured as a trial. The dynamometer of this type has high practical application on account of easy manufacture and compactness. For the design of this dynamometer, both the static characteristics and the interaction of a circular-hole one-component dynamometer with respect to the change of dimension are analyzed by Finit Element Method. Finally various types of dynamometers manufactured using this structure are introduced.

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Hole positional accuracy, which is important in drilling operations with automated machine tools, e.g. NC machining-centers, is examined by a special runout device. Positional deviation of a drilled hole from the spindle rotating axis is mostly determined at the beginning of penetration. This deviation is caused by the deflection of tool rotating axis around a certain point on chisel edge. The experimental results indicate the drill overhang length has a significant influence on the hole positional accuracy. A fine feed in start of drilling and a spiral type of drill point grinding are effective to reduce such deviation. Stub tooling system, which gives a strong bending rigidity of tool, is a desirable technique to improve the positional accuracy in drilling operations.

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This paper presents a theoretical analysis of a wave energy converter consisting of three floating bodies which are connected by links and are oscillating subject to a sinusoidal wave. By taking account of the radiation and diffraction problems on an n body system and by using the relation of Haskind, governing equations for a three body system have been obtained under the constraint of links. System parameters such as body distance, configuration of the body, and coefficient of viscous damping have been optimized to get maximumenergy converting efficiency for a symmetrical and especially for an asymmetrical arrangement. The results are that most of the energy in the incident wave can be absorbed in a wide frequency range particularly for an asymmetrical case and that this energy converter will be useful as a wave suppresser since the amplitudes of the transmitted waves are reduced substantially.

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