The macroscopic shear modulus and the loss factor of a sea-island type polymer alloy are evaluated under the shear applied stress by using the equivalent inclusion method combined with the Mori-Tanaka theorem. The effects of the shear modulus and the loss factor of the spherical island particle on the macroscopic loss factor of the polymer alloy are clarified in the form of the two-dimensional contour map. Moreover, it is found that an optimum range on the magnitude of the shear modulus of the particle in the polymer alloy exists for its larger macroscopic loss factor, and the additional voids in the matrix play an effective role in decreasing in the macroscopic shear modulus and in the further increase in the macroscopic loss factor of the polymer alloy.

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Within the framework of the dislocation theory, we analyzed the behavior of discrete screw dislocations in an elastic system, subjected to transverse shearing, composed of a semi-infinite substrate and a completely bonded surface-layer. The fundamental equations for the image stress due to the discontinuity of the shear modulus at the interface and the surface were derived using the concept of image dislocations. The results of the analysis and dislocation dynamics simulation showed that if the shear modulus of the surface-layer is lower than that of the substrate, the movement of dislocations escaping from the surface is suppressed by the reduction in the applied stress and attractive image stress. In the case of the surface-layer with a shear modulus higher than that of the substrate, the dislocations in the substrate are arrested in the vicinity of the interface by the repulsive image stress. However, such arrested dislocations generate a high stress filed in the surface-layer, so that fracture can occur from the layer even under a relatively low remote applied stress.

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An analytical solution is presented for an axisymmetric contact problem of an elastic layer subjected to a tensile stress applied over a circular region. This mixed boundary-value problem is effectively reduced to an exact solution of an infinite system of simultaneous equations in which the normal displacement in the circular region is expressed as an appropriate series. The normal contact stress between the elastic layer and the rigid plate and the normal displacement in the circular region, as well as the stress singularity factor, are shown in curves calculated numerically. The effects of the layer thickness and Poisson's ratio on stress and displacement distributions are discussed.

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On the basic of the classical small-deflection theory, the purely analytical solution for the deflection due to the bending of a clamped elliptical plate subjected to the combined action of uniform lateral load distributed over its entire surface and uniform in-plane force distributed in its middle plane is derived in the elliptical cylinder coordinate system. The general solution of the differential equation for the deflection surface is expressed in the form of an infinite series of Mathieu functions and the final solution satisfying the boundary conditions is derived by using the orthogonality of Mathieu functions. In additon, the bending moment distributions are formulated rigorously in the form of infinite series. Special cases of an elliptical plate without the action of in-plane force and a circular plate under the combined action of uniform lateral load and in-plane force are also discussed in detail. It will be shown that the deflection and the bending moments are directly proportional to the uniform lateral load whether or not the in-plane force acts along the periphery. Numerical calculation results will be given in tables and figures.

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In the previous paper, we presented an axisymmetric solution for the stresses and displacements in an elastic thick plate containing an oblate spheroidal inclusion under circular bending around the edge of the thick plate. In the present paper, we studied an asymmetric solution for an elastic thick plate containing an oblate spheroidal inclusion under transverse bending around the y axis. Numerical results are given for different values of size, aspect ratio and stiffness ratio. The stress distributions around inclusion are shown graphically, and are compared with the axisymmetric results.

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The microscopic deformation of a particulate reinforced metal matrix composite was modeled by a unit cell model with Mises and Gurson yield conditions based on metal plasticity. The numerical predictions were compared and calibrated with the results of monotonic experiments of a cast aluminium alloy discontinuously reinforced with SiC particulates with and without thermal cycling. The responses of monotonic work hardening and the microscopic fracture mechanisms were investigated numerically. The micromechanical considerations of monotonic deformation in the particulate reinforced metal matrix composite were examined. (1) Whether there is a plastic deformation band penetrating a matrix or not, is the controlling factor of the magnitude of a work hardening rate for particulate reinforced composites; with or without thermal cycling. (2) For T7 treated composites, the maximum stress in the particle was larger than that of the interfacial average stress. For the composite with thermal cycling, the maximum particle stress was less than that of the interfacial average stress.

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We propose an apparatus measuring the tension of the isotropic membrane and show its characteristics. The apparatus uses the load-displacement relation of the circular membrane with the geometrically non-linear strain, which is subject to the concentrated lateral load at the center of the membrane. The non-linear load-displacement relation of the above membrane is obtained by the rigorous numerical solution and several practical approximate solutions.

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In this paper, a shape optimization procedure for a flexible structure which shows strong nonlinearity like rubber is presented. This method follows the idea of the traction method proposed by Azegami but is extended to handle any kinds of nonlinearity. It is formulated in a complete discrete form and not the surface traction force but the body force is applied, so the method is termed as ‘discrete force method’. In this study, in order to verify the validity and effectiveness of the present method, some shape optimization problems of rubber like structures are considered with the nonlinear finite element program for hyperelastic material using the Mooney-Rivlin law and combined with the present method. The first simple numerical example of the plate with a center hole shows the validity of the present method and the second analysis of the flexible micromanipulator shows applicability to the practical problem.

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The motion of point vortices in a plane is considered. The aim of this paper is to discuss the vortices which exhibit the relaxation oscillations. Five vortices as well as three ones are treated. The numerical simulations and mathematical result are shown.

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In this paper, the stability of adaptive structures during steady periodic motion is discussed. The adaptive structure in this paper is a two-dimensional variable geometry truss which consists of N bays. The structure controlled by a periodic optimum controller converges into "2-link mode" in which N-1 bays are the same shape. The results of numerical calculation show that 2-link mode satisfies the optimal condition. Periodic optimum controller has other possibility that the structure converges into a locally optimum mode. To confirm that the system does not stay the locally optimum mode, the stability is examined with eigenvalues and eigenvectors that are derived from a linear system. The results show that the structure in 2-link mode has global stability to keep the steady motion. It is also shown that the other locally optimum modes are unstable neutral points.

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Protein is a water soluble nano-particle and has the biological functions. Some protein has the activity of self-assembly; that is this type of protein interact each other and organize a structure. These assembled proteins (super molecules) such as the bacterial flagella have another functions as a whole. We found that the randomness play an important role both for the intra-molecular organization of protein into a functional structure and for the inter-molecular organization of proteins into a functional assembled super-molecules. With this study most of the proteins are suggested to have an activity of the organization into a particular super molecule.

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The purpose of this paper is to develop a laser tracking system and an integrated laser propulsion/tracking system for realizing a continuous flight and control of a laser-driven micro-airplane. The laser propulsion is significantly effective to achieve the miniaturization and lightening of the micro-airplane. The laser-driven micro-airplane has been studied with a 0paper-craft airplane and YAG laser, resulting in a successful glide of the airplane. It is required that the irradiated laser is tracked to the moving micro-airplane with the laser tracking system. Furthermore, the laser propulsion system has to be combined with the laser tracking system to supply repetitive propulsion. Fundamental experiments are carried out to evaluate the performance of the developed laser tracking and laser propulsion/tracking systems.

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In this paper, a useful design tool that deal with 3-D topology optimization is being developed. Traditionally topology optimization is a tool for CAE engineers, but here we aim to develop a tool that gives design engineers inspiration of structure in conceptual design stage in structural mechanics sense. To help designers, the interactiveness and flexibility against the user operation is necessary. To achieve the goal, topology optimization using the adaptive multi level voxel analysis is used. With 3 dimensional examples it was demonstrated that several possible designs can be obtained interactively.

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We present two-dimensinal numerical results of flow around two circular cyrinders in tandem arrangement and show features aerodynamic vibration of the circular cylinders at a certain spacing between two circular cylinders. Two circular cylinders are located in a uniform flow and are supported elastically by two degrees of freedom. In this computation, the finite element approximation is applied to the Navier-Stokes equations, and the Euler implicit scheme is used for numerical time integration. The Reynolds number is set as 1000.

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The characteristics of vibrational and rotational temperatures distributions of N2, O2, and NO along a stagnation streamline were investigated numerically in detail by the extended merged shock-layer theory for reentry flows. The calculation was based upon an 8-temperature and 11-chemical species model. The analysis assumed a continuum approach and the system of governing equations constituted a two-point boundary value problem that was solved using the SAR method. It was found that the effects of thermally and chemically nonequilibrium phenomena intensely appeared in the entire shock layer, and that the distributions of vibrational and rotational temperatures for each molecule were quite different from each other, and also from that of translational temperature.

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Engineering application of the Knudsen pump to space satellite control system is considered. The Knudsen pump is a new vacuum pumping system that utilizes a thermal transpiration flow that is peculiar to a rarefied gas. There is no moving part in this pumping system and the mechanism is so simple that many possible applications are predicted. In this paper we investigate the basic features of the Knudsen pump numerically, and suggest the possibility of application to the artificial satellite control system.

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Growth of a point source disturbance in the three-dimensional boundary layer of a yawed circular cylinder is studied using a direct numerical simulation (DNS). This study was undertaken to investigate the propagation characteristics of disturbances introduced from a point source and to find out whether the dominant instability mode is affected by the forcing frequency. Two frequencies, high and low, are studied. The cross-flow instability mode is dominant at low frequency. The instability mode is judged to be a cross-flow mode, even though typical features of viscous modes are present in the amplitude and phase profiles at high frequency. This determination is clarified and the risks of judging instability modes using only the amplitude and the phase profiles are described.

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This paper shows the results of aerodynamic and acoustic analysis of rotor higher harmonic control (HHC) using a CFD technique. HHC is one of the techniques for rotor blade-vortex interaction (BVI) noise reduction. A moving overlapped grid method is applied in the CFD code and three types of grid, inner and outer background grids, and blade grid are used to accurately simulate the blade-vortex interaction (BVI) phenomena. The calculated model is a single-blade rotor and the experimental data was obtained by the cooperative work between JAXA and Kawada Industry. In this calculation, the frequency of HHC is 20Hz (2/rev), and the amplitude is ±2.6°. 72° and 250° of control phase angles are chosen. These phases are selected for the weak BVI noise case and strong BVI noise case in the wind tunnel test, respectively. Our CFD code well captured the HHC effect on the blade surface pressure and acoustic waveform. However, the tendency of computed noise with respect to the control phase shows the reverse tendency compared with experimental results.

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When the high-pressure gas is exhausted to the vacuum chamber from the nozzle, an underexpanded supersonic jet is generally formed. The jet structure is complex, involving the interaction of the several flow features, making this a demanding problem. Two types of shock reflection appear to occur in the jet structure, regular and Mack, depending on the jet pressure ratio. The existence of a dual solution domain is well known from regular and Mack reflection flow structure for two-dimensional flow. The purpose of this study is to clear the pressure-ratio-variation-induced hysteresis phenomenon of shock reflection type for an underexpanded supersonic jet. The numerical analysis is carried out in the region of exit Mach number from 1 to 2.5 , the axisymmetric conservational equation is solved by the TVD method in the numerical calculation. The results of the numerical calculation are used to clear the jet structure and compared with the results of hysteresis phenomena obtained by Gribben.

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The upper-level anomaly pattern corresponding to the appearance of the midsummer surface Okhotsk high is identified. It is confirmed that the pattern is well correlated with surface air temperature anomaly in northern Japan. Positive kinetic energy conversion from the basic field to the anomaly field is estimated, corresponding to the anomaly pattern. The steady response patterns are calculated by a linearized numerical model, giving forcings distributed over the entire Northern Hemisphere. The statistical analysis for the responses detects an anomaly pattern similar to that obtained in the observational analysis. These results suggest that the anomaly pattern associated with the appearance of the Okhotsk high can appear, in relation to the structure of the basic field, even if external forcings are homogeneously distributed.

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A new model for large eddy simulation(LES) of premixed combustion has been proposed and tested in the present paper. The model is based on the G-equation, in which a level set method and the dynamic subgrid model of turbulent flame speed are incorporated. The mathematical feature of the filtered G-equation in the present formulation is consistent with that of the original one due to the introduction of the level set method. Therefore, discontinuity in hydrodynamic quantities across corrugated flames can be properly captured. In addition, the turbulent flame speed can be computed dynamically as a part of the calculation by modifying its procedure in conjunction with the level set method. For comparison, numerical simulations by two different G-equation models have been also conducted. It is found that the level set approach to the G-equation is effective to prevent the thin flame from broadening. It is also confirmed that the subgrid turbulent intensity is one of the most important factors in modeling the turbulent flame speed.

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With the use of the ultrasonic velocimetry, we measured the velocity profiles in thermal turbulence in mercury. The measurement, which is different from the traditional measurement of time series of the local velocity, has brought about some intriguing results. We observed the inversion of the flow direction near the boundary plate, which seems the appearance of the velocity boundary layer.We also elucidated the nature of the fluctuation in thermal turbulence through the principal component analysis. The macroscopic flow structure and its vertical movement were observed. In addition, the energy spectrum and the velocity structure functions were calculated without employing Taylor's frozen-flow hypothesis for the first time in thermal turbulence, which appeared to be consistent with the Bolgiano-Obukhov theory.

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A fundamental analysis of a simple interaction between a rotor and a vortex externally generated from a vortex generator is numerically performed to clearly understand the phenomenon of main-rotor/tail-rotor (MR/TR) interaction noise of helicopters. A combined method of a 3D unsteady Euler CFD code and an acoustic code based on the FW-H formulation is used. As a result, the effect of intersection angle and interaction position on the noise intensity was understood. The directivity of MR/TR interaction noise was also understood.

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We present calculation of compressible flow based on solving the Navier-Stokes equations at equal intervals in Cartesian coordinate system. For a fundamental understanding of unsteady flow, we apply the multi-directional upwind finite difference method to the compressible flow past bluff bodies of various shapes. In order to catch the complicated nature of flows around bluff bodies, it is effective to use the multi-directional upwind finite difference method for all the space derivative terms.

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Theory of Generalized J-integral(GJ-integral) by the author(1985) is applicable to elliptic boundary value problems, which relate to shape sensitivity analysis of potential energies. GJ-integral catch the movement of singular points, for examples, boundary, the interface in mixed boundary value problems, the edge of cracks in fracture problems. In this paper, the summary of GJ-integral theory is written. In transmission problem, the singularities also appear, however theory is not directly applicable by discontinuity of coefficients in partial differential equations. New attempt to transmission problems and its numerical calculation by FEM are done in the case-diva∇u=f in Ω . Here a=a1Χ1+a2(1-Χ1)with smooth functions a1,a2 > 0, using the characteristic function Χ₁ of Ω₁ ⊂⊂ Ω .

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The Cauchy problem of the Laplace equation is a typical example of ill-posed problems in the sense that the solution is unstable for the Cauchy data. The aim of our research is to solve the Cauchy problem of the Laplace equation numerically. Then we propose a high order finite difference method in which quadrature points do not need to have a lattice structure. We interpret our method from the viewpoint of the exponential interpolation. From numerical experiments, we confirm that our method is effective for solving the two-dimensional Cauchy problem of the Laplace equation.

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This study is concerned with the identification of chaotic vibration by continuous wavelet transform technique. The time histories to be examined are from numerical simulation of dynamic response of a nonlinear seven degrees of freedom full-vehicle model. The results of continuous wavelet transform for the time histories with five mother wavelet, Harr, Mexican Hat, Meyer, Morlet and Daubechies are discussed. It is found that the selection of mother wavelet in the identification is necessary. It is shown that the chaotic motion and almost-periodic motion can be distinguished with presented method when power spectra analysis fails to do so. As a qualitative technique, the continuous wavelet transform could be used in searching for the boundaries of chaotic and non-chaotic responses.

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Two kinds of Star dunes are simulated numerically in order to make clear the mechanism of their formation. The flow above the sand dune has been investigated by using Large-Eddy Simulation (LES) method. The numerical method employed in this study can be divided in three parts: (i) Calculation of the air flow above the sand dune by using standard MAC method with a generalized coordinate system; (ii) Estimation of the sand transfer caused by the flow through the friction; (iii) Determination of the shape of the sand surface. Since the computational domain is changed due to step (iii), these procedures are repeated until typical shape of the sand dune is formed. Two cases of dunes are simulated. In the first case, when the winds blow from three directions, the sand dune extends at three directions and becomes the shape of a star with three arms. In the second case, when the winds blow from three pairs of opposing directions, the sand dune extends in four directions, becomes the shape of a star with four arms.

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This paper presents a lattice Boltzmann method (LBM) for incompressible flow simulation applicable to complicated flow domain using unstructured triangular mesh. The LBM simulates microscopic collision and streaming of fluid particle and evaluated the macroscopic velocity and pressure from the computed particle distribution. For the computation of collision step, the 2-dimensional 9-speed lattice BGK model was employed as a collision operator. For the streaming step, the cubic interpolation scheme based on CIVA was employed to interpolate the particle distribution function. The present method was applied to the analysis of the square driven cavity flow and the flow past a circular cylinder.

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Effects of horizontally differential atmospheric rotation are considered in geostrophic dynamics of planetary and stellar atmospheres. The Coriolis parameter defined by the angular velocity of a basic flow ƒ and the latitudinal gradient of the angular velocity Γ are used in the present study. Nondimensional differential rotation factor Γ/ƒ and Rossby number Ro determine whether the geostrophic approximation can be applied to differential rotations of planetary and stellar atmospheres, or not. When an eddy with small intrinsic phase velocity satisfies the condition of Fr ≤ 1 (Fr: Froude number) and L/a ≤ Ro << 1 (L: eddy horizontal scale, a: planetary radius), for rigid-body rotation (Γ/ƒ << Ro² or Γ/ƒ Γ ∼ Ro²) and weakly differential rotation (Γ/ƒ ∼ Ro¹), the geostrophic approximation can be applied. However, for strongly differential rotation (Γ/ƒ ∼ Ro⁰), the geostrophic approximation cannot be applied, even when Ro is sufficiently small.

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This paper tries to select a plausibe heteroskedastic time series model which explains the daily logarithmic returns of the Nikkei 225 index of the Tokyo Stock Exchange from Jan.4, 1950 through Dec.30, 1999. Several new summary statistics are presented for this purpose. The results depend on its subperiods. On the average, among AR(1), ARMA(1,1) and nine GARCH type models we studied, ARMA(1,1)-GARCH(1,1) model is found to be plausible.

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Option replication is discussed in a discrete-time framework with transaction costs. The model represents an extension of the m(≥3)-nomial option pricing model to cover the case of proportional transaction costs. The method is based interval by a locally risk-minimizing strategy.

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