A creep constitutive equation of Hastelloy X was obtained from available experimental data. A sensitivity analysis of this creep constitutive equation was carried out. As the result, the following were revealed : (i) Variations in creep behavior with creep constitutive equation are not small. (ii) In a simpler stress change pattern, variations in creep behavior are similar to those in the corresponding fundamental creep characteristics (creep strain curve, stress relaxation curve, etc.). (iii) Cumulative creep damage estimated in accordance with ASME Boiler and Pressure Vessel Code Case N-47 from a stress history predicted by "the standard creep constitutive equation" which predicts the average behavior of creep strain curve data is not thought to be on the safe side on account of uncertainties in creep damage caused by variations in creep strain curve.

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This paper describes the typical finite element methods and the variational principles for two elastic contact bodies. The following results are obtained in this paper : (1) The two-dimensional behavior for the longitudinal impact of two uniform rods is calculated, using the tinite element method for elastoimpact contact structures. An impact contact force is decomposed into a stationary component due to contact displacement and a variable component due to contact acceleration. The variable component is within the range of a maximum ±10.4 %. Therefore, the impact force can be approximately expressed by the stationary component. (2) The stationary component of the impact force corresponds to a Lagrange multiplier in the variational principle. An approximate hybrid type of virtual work principle is formulated in various contact and separate states of two bodies. If the components of velocities and accelerations are eliminated in this principle, a precise virtual work principle for static contact structures can be derived. Using the concept of relative movement, the matrices degree of the finite element method based on this principle remains constant in various contact and separate states.

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Based on the previous experiment on the statistical nature of the crack initiation life t_i and the crack propagation life t_p in stress corrosion cracking of a high strength steel in 3.5% NaCl, the distribution of the total lives t_f (=t_i+t_p) is studied theoretically assuming that both t_i and t_p follow Weibull distributions. It is shown that t_f follows a composite Weibull distribution approximately. This composite Weibull distribution is similar to the distribution of t_p in the shorter life region, and to that of t_i in the longer life region. The bent portion moves downwards on Weibull probability paper with an increase in the average ratio of t_i to t_p. The concepts of "initiationdominated distribution" and "propagation-dominated distribution" are proposed. Furthermore, a new interpretation of a composite Weibull distribution is presented.

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The object of this paper is to experimentally assess the applicability of HRR solutions for the strain distribution in the near-tip field under the general yielding and stable crack growth. The measurement of strain components of a l.2mm thick SUS 430 stainless steel compact tension specimen was performed by using the Moire method. The phenomena of the formation of the "blunting strain gradient zone ( BSGZ )" defined by the authors are discussed by the comparison between the experimental results and analytical ones obtained by HRR formula. It is clear that the HRR solutions, except those in the BSGZ, are valid to evaluate the strains in the near-tip field of a ductile thin metal sheet under the general yielding and crack growth.

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The infiltration of a fluid into a dry poro-elastic layer resting on a very porous, rigid foundation and the associated mechanical behaviors, especially the layer compaction and the fluid front moving, were investigated. The solutions were obtained by Landau's transformation and the Crank-Nicolson finite-difference scheme. The numerical calculations are based on the data of material constants for alundum, sandstone, felt, and polyurethane foam. The results are shown in the form of curves and compared in the ab initio fluid-pervaded case. Furthermore, estimates by the incompressible model as well as by the rigid skeleton model are discussed.

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In transonic turbine blades with thick trailing edge, the base pressure strongly influences the cascade performances. This paper presents two methods for predicting the base pressure, which are extension of the analyses on the backward facing step by Korst (neglecting upstream boundary layer) and McDonald (taking account of upstream boundary layer). The compatibility is considered between separated flows (jets) from suction and pressure surfaces in each method. The validity of both methods are discussed in comparison with the experiment of a two-dimensional turbine cascade with high stagger.

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From the experimental results of a reattachment flow issuing from a finite width nozzle having various aspect ratios, it is made clear that behaviour of the flow is influenced by nozzle shape, Reynolds number and initial turbulence intensity. As aspect ratio of the nozzle becomes smaller than 3, behaviour of the flow changes considerably, influenced by the side plates. The calculated results for a two-dimensional reattachment flow are not valid for such a flow. A new correction factor is introduced as a function of aspect ratio, offset ratio and Reynolds number. As the result, the reattachment distance of a flow having a small aspect ratio can be expressed by using this factor in a wide range of offset ratios, except very small ones.

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A numerical study is made of the characteristics of turbulent submerged axisymmetric incompressible jets impinging on a flat plate. The purpose of the study is to obtain a better understanding of the behavior of a fluid jet used to cut solid materials. In the computations a hybrid finite difference method is used to solve the full Navier-Stokes equations for an incompressible submerged jet. A two-equation turbulence model provides a turbulent kinetic energy equation and a turbulent energy dissipation equation (k∼ε model). For cells at the wall, kinetic energy is assumed to be parabolic in the viscous sublayer and linear in the fully turbulent region. All computed results are compared with experimental data reported in the literature. The computations are made for nozzle-to-plate distances ranging from 2 to 18 nozzle diameters. The two-equation k∼ε turbulence model results in good predictions of the velocity distributions, pressure, and skin friction. Also the near-wall models for kinetic energy and turbulent shear stress give good predictions of the skin friction coefficients.

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A solid -sphere drag is measured at low Reynolds numbers, of which the estimated uncertainty is ± 1.2 %. The measurements show that the Stokes formula for the sphere drag is applicable only at Re=0 and that the Oseen formula for the sphere drag represents the actual drag most accurately at the Reynolds numbers below 0.4. Here the Reynolds number is related to the sphere diameter. New method to visualize streamlines for the steady flow past a body is developed by exploiting a naturally occurring phenomenon in glycerol. An application of this method to visualization of streamlines around a solid sphere reveals that the first -order solution for the Oseen equation represents the flow field around a sphere most accurately at the Reynolds numbers below 0.4.

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In application of laser doppler velocimetry (LDV) to the flow field including flames, there are interactions of the laser beams with flames. Those interactions are schlieren effect and phase effect. In this study, such interactions were investigated experimentally and theoretically. The main results of the investigation are as follows : (1) The effect of interaction between laser beams and flame front on LDV was measured actually. (2) The effect is serious only for near-tangential incidence of laser beams to flame front, when large pseudo-velocities are produced in very short time interval. (3) The value of pseudo-velocity is proportional to the flame speed, and it increases with the flame size. (4) The pseudo-velocity maybe become serious when the relative incidence angle of laser beam to flame front fluctuates by such a high frequency as in strong turbulent flames.

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The clearance between cylinder and piston of the internal combustion engine is expected to be deformed by heating in operation, and its thermal deformation is closely related to lubrication, cooling, friction and blow-by. To measure the thermal deformation of this clearance, an air-cooled two-stroke-cycle engine was chosen as an experimental engine. The applied measuring method, called " Quick Stopping Method " by the authors, is practical because the thermal deformation can be easily measured by dial gauges. As a result of this series of experiments, it was revealed that local close-fit condition sometimes arose between cylinder and piston even in its normal operation.

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Effects of an anisotropic scattering on heat transfer by simultaneous conduction and radiation in an absorbing, emitting and anisotropically-scattering medium are investigated theoretically. Consideration is made of a one-dimensional system bounded by two parallel gray, diffuse and isothermal walls. First, to select a useful phase function for evaluation of heat transfer characteristics, three kinds of one-parameter phase functions ( a linear phase function, the Kagiwada-Kalaba phase function and the Henyey-Greenstein phase function ) are examined. Consequently, we find that the Henyey-Greenstein phase function is the most useful of them. Then, the effects of anisotropic scattering on temperature profiles, heat transfer characteristics and heat flux distributions are investigated systematically by means of this phase function. Furthermore the effects of the anisotropic scattering on heat transfer by thermal radiation alone are examined, too.

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An analysis is carried out on the radiative heat transfer in a nonisothermal, nonhomogeneous atmospheric boundary layer. Nongray gases and atmospheric aerosols are considered to emit, absorb and anisotropically scatter radiation energy. The effect of size, optical constants and concentration of aerosols on heating rate are studied. Various conditions of the atmospheric layer are considered. The maximum effect of the aerosol diameter is found in the case of the diameter being nearly equal to the wavelength of the visible light. The effect of the imaginary part of the complex refractive index of aerosol on the heating rate is very large. A complex, large dependence of the heating rate on the humidity is recognized. When the urban atmosphere is treated, the influence of the aerosol on the radiative heat transfer is strong, and an inversion layer may be produced by the aerosol.

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The free vibrations and the forced vibrations of a system of two elastically connected parallel upper and lower beams having unequal masses and unequal flexural rigidities are analysed by using a generalized method of finite integral transformation and the Laplace transformation. The natural frequencies and the amplitude ratios for the normal modes of vibration are presented explicitly, and the effects of mass ratio and flexural rigidity ratio of the beams are discussed. It is also shown that a system consisting of a lower beam and coupling springs can be used as a dynamic vibration absorber to reduce the vibrations of the upper beam subjected to a periodic force. An elastically connected multi-beam system is compared with a multi-degree-of-freedom-mass-spring system, and their similarity is pointed out.

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This paper deals with the forced self-excited vibration of a one-degree-of-freedom system with time lag in the nonlinear restoring force term. The resonance curve and stable zones of harmonic, l/3-harmonic, and third higher harmonic vibration and beats developed from harmonic vibration are obtained. The effect upon these vibrations of the variation in time lag is investigated. The influence of initial conditions on the steady state solution is also examined by means of integral curves. It is well known that self-excited chatter vibration of a work-piece during cutting is due to time lag and to the soft spring effect of the restoring force, depending upon the relationship between the cutting force and the thickness of chip. The experiments with an external periodic force during chatter vibration confirm the qualitative correctness of this theoretical analysis.

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This paper presents the results of theoretical and experimental studies which have been carried out to investigate the diametral vibration modes of rotating bladed discs. The theoretical model has been considered as a linear system and only the diameter modes have been discussed. The vibration of the bladed disc has been obtained by superposing vibrations of discs assumed to have a single blade respectively, so that the exciting condition has been derived. This condition depends upon the relations among the number of rotating blades, the number of exciting sources on the stationary side and the number of diametral nodal lines. These relations have been verified by experimental results. It is confirmed that the disc does not resonate when the exciting condition is not satisfied, even if the exciting frequencies coincide with natural frequencies of the disc.

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Two analytical methods are introduced by which changes of the natural frequencies, the natural modes and the dynamic response due to alteration of the local physical properties (i . e ., mass, stiffness, damping, shell thickness etc.) of a structure can be predicted easily, using the modal parameters of this structure before alteration. A computer program by one of these methods is made for practical use. The values of change in the physical properties of a structure necessary for alteration of the natural frequency to specified value can also be calculated using this program. The time necessary for calculation with this program is far shorter than by direct use of the finite element method. The calculated results with this program are in good agreement with the experimental ones and the results of the finite element analysis.

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"Wave Propagation Technique" and "Cyclic Symmetry Method" are very useful for analyzing vibration of periodically symmetric structures consisting of columns with hollow centers. However, these two methods are not applicable to periodically symmetric structures consisting of columns with solid centers, because the solid center connects all the substructures to form a total system. As a result of improving these two methods, a new analytical method is proposed in this paper. Using the proposed method, the vibration characteristics of a total system can be predicted simply by analyzing one fundamantal substructure which is separated from the total system regardless of whether the center of a periodically symmetric structure is solid or hollow. The application of this method to specific structures, and the accuracy and efficiency of the method are discussed in detail.

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A method is presented to calculate the sound pressure produced by the structural vibration based on the results of the numerical or experimental vibration analysis of the structure. The vibrating surface is divided into rectangular elements. It is assumed that the finite element analysis gives the displacements and rotations of the node points of each element and the experimental analysis gives the displacements. The interior displacement of an element is expressed by an interpolation function. The sound pressure produced by each element at a point in space is given by integrating a function that includes the interpolation function. The sound pressure produced by the whole structure is calculated by summing up the contribution of each element. The accuracy of the interpolation function is examined. An application of the method to the prediction of the pressure of the sound radiated by an engine block model is presented.

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A method is proposed to calculate the resonant amplitudes of pressure pulsation in pipelines by using transfer matrices in which equivalently linearized damping forces are employed. The resonant curves for several pipelines with an orifice, a tank or a branching are calculated. The results show good agreement with the experimental values. The pressure amplitudes for the 2nd harmonic component which arise from the piston-crank mechanism are calculated and are superposed on ones for the fundamental component. The results also show good agreement with the experimental values.

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Free surface oscillations of a liquid partially filling a rotating cylinder which are called centrifugal waves are investigated both analytically and experimentally. In this report, general properties of centrifugal waves are analyzed under the assumption that the equilibrium state of the motion is a rigid-body rotation. First, phase velocity and eigen modes are analyzed on basis of inviscid theory, the results being confirmed by the resonant mode visualization. Second, resonant amplitudes of free surface elevation when the rotating cylinder is forced to move sinusoidally in the horizontal direction, are calculated. The results are in good agreement with the experimental ones. Third, the relation between the forcing frequency and the resonant mode is considered.

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Free surface oscillations of a liquid partially filling a rotating cylinder are investigated analytically, taking the effect of viscosity near the wall into consideration. In this report, the fluid force acting on the rotating cylinder, when it is forced to move sinusoidally in the horizontal direction, is calculated by using boundary layer approximation. The results show that the fluid force consists of two components, one of which is in phase with the forcing displacement and the other is out of phase by 90 degrees with it. The results also show that the contribution of wall curvature to the calculation of the fluid force is negligible when the viscosity of the liquid is small.

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The free vibration of a helical spring is analyzed by a finite element method. The mass and stiffness matrices including the effects of the pitch angle and the number of active coils are derived by using the exact solution of the equations of the helical spring in static equilibrium, and the natural frequencies and associated modes are estimated numerically. The effects of the pitch angle and the number of active coils on the natural frequencies are studied closely, and it is pointed out that the effects of the pitch angle, even if minor, should be taken into consideration. The obtained results are corroborated with the experimental results.

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In this paper gear performance on vibration is discussed in a wide range of contact ratios from 1.26 to 2.46 using a developed simulator. And tooth profile correction is investigated in relation to pressure angle error. The simulation results are verified through good agreement with results of dynamic meshing tests. From this investigation the effects of contact ratio and profile correction are clarified.

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Indentation of sintered metals with square-based pyramids is performed and the relationship between the hardness and the compressive flow stress of the sintered metals in obtained. When the semi-angle α of the pyramid is 68°, which corresponds to the semi-angle of a Vickers hardness indenter, the ratio of the hardness to the flow stress is dependent upon the relative density. However, when α is 45°, the ratio is a constant value of 2.7 without influence of the relative density. Therefore, the flow stress of the sintered metals can be estimated from the hardness measured by using the indenter with the semi-angle of 45°.

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