The method of caustics is one of the optical measurement method witch is used to determine the stress intensity factor of a crack tip and the contact force. Determining physical parameters using this method, simulation of caustic images are necessary based on the theory of elasticity or the numerical analysis. We developed a simulation system of the caustic image adopted to the general finite element method software. Using this system, gradients of a stress state are easily/automatically calculated for the caustic image simulation. The developed system was applied to 2-Dimensional crack problem and confirmed the effectiveness the simulation system.

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Biaxial tests were conducted by using cruciform specimens to obtain failure strength of quasi-isotropic carbon fiber/epoxy resin composite laminates. A stacking sequence of the laminates was (0/90/45/-45)s. Cruciform specimens were subjected to biaxial load by a biaxial testing machine with various biaxial load ratios, and strains were measured with strain gauges placed on the gauge area. Biaxial load ratio is not coincident with biaxial stress ratio due to the specimen configuration. Relationships among biaxial load ratio, strain ratio, and stress ratio were estimated based on measured strain for the cruciform specimen under uniaxial load. Experimental results indicated that failure strains under biaxial loading are less than those under uniaxial loading, which were measured by using strip specimens.

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Load carrying capacity of the crossed helical gears is considered to be low since the theoretical meshing is of a point contact. However, there is a possibility that a comparatively strong power can be transmitted because the contact area is widened by the elastic deformation and wear of gear teeth. In this study, the load carrying characteristics of the plastic (polyacetal co-polymer) crossed helical gears were investigated. The endurance tests for the plastic crossed helical gears of helix angle of 20 degrees were performed with the angle between shafts of 40 degrees and a rotational speed of 500rpm (about 1m/s in tangential speed). Temperatures of meshing teeth and atmospheric temperature were measured during operation and the fatigue life of gear teeth was determined. As a result, the relation between the life of gears and temperature of meshing teeth was clarified. And the relation between temperature rise from atmospheric temperature of meshing teeth and load torque was clarified.

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In order to keep structural reliability, it is important to monitor the damage level in the structure elements quantitatively. In this study, by using the wireless transmitter and receiver, we try to measure the surface strain information of the specimen on rotating bending fatigue test. Also, the states of crack initiation and propagation are examined with the change of surface strain. Base on the experimental results, it is shown that the crack initiation when the crack length reaches about 1.3 mm can be detected by monitoring the change of surface strain.

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It is important to know the stress intensity factor (SIF) interactions for two non-aligned unequal elastic cracks in order to determine the toughness ratio K,. as the ordinate in the FAD. Although the numerical values of the SIF solution for two non-aligned cracks are available in some configurations from the reference literatures, there are no approximation expressions for the interaction factors for two non-aligned elastic cracks. In this paper, the SIFs for two non-aligned unequal through-wall cracks under remote tension in an infinite elastic plate are solved with the aid of the body force method and approximation expressions for interaction factors are proposed. Using the proposed expressions, contours of stress intensity factor interaction are plotted. Based on the results, the condition in which the interaction of mutual cracks can be neglected is proposed.

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Assessment of overlapped internal and external volumetric flaws is one of the most common problems relating to pressure vessels and piping components. Under the current Fitness for Service (FFS) rules, such as ASME, BS and so on, the procedures have not yet defined how to assess these flaws. In this paper, a new procedure for these volumetric flaws is proposed for assessing the flaws by the p-M (pressure-moment) Diagram method, which is a simple assessment procedure. Numerous FEAs for a cylinder with overlapped internal and external flaws were conducted to verify the proposed procedure. There is good agreement among them.

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A system of Voxel CFD (Computational Fluid Dynamics) simulation technology cooperated with high energy X-ray CT (Computed Tomography) is developed. Computational model is obtained from "real object" using industrial X-ray CT, and then several CAE (Computer Aided Engineering) simulations are executed. These simulations are called "convergence technology simulations". They are expected to investigate the effect of difference between real product and 3D-CAD (Computer Aided Design) model, and improve the quality of products. Many of the past convergence technology simulations treated single material mechanical part because of the simplicity to obtain the model and to generate computational grid. In this study, a detailed 3D model of LCD (Liquid Crystal Display) projector, which is made of some materials such as glass, resin and metals, is obtained, by high energy X-ray CT, and flow simulation inside the whole body of the product is executed using Voxel CFD simulation to enable to generate computational grid, even if the geometry is highly complicated. The computational results are compared with the result of simulation from 3D-CAD model.

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To develop an isothermal container to transport regenerative medicine, a prediction method and a design tool have been developed. In the first report, the performance of the basic structure adopting vacuum insulation panels (VIPs) and phase change material (PCM) was investigated experimentally. In this report, we describe the computational and experimental results of new prototype container. To modify it, the size of the isothermal container was halved, two VIPs were added to the top and bottom surfaces, and two cases of PCM were arranged to reduce heat loss. We tested this modified container, and results showed that it was possible to keep the temperature constant at over 35.5℃ for 40 hours. We computed the temperature change of the container include the solidification process of the PCM .The simulation results showed the computed time that the inner temperature of the container was kept at over 35.5℃ was approximately 30% shorter than the time in the experimental data. The temperature trend of the transported object was simulated reasonably well.

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We have developed CFD code, CRIMSON (Civa RifIned Multiphase SimulasiON), to analyze multi-phase flow in engineering and industrial apparatus. The CRIMSON has some problems in calculation of high temperature and high-pressure gas behavior. In this study, we improve the basic algorithm of CRIMSON to fit the high-temperature and high-pressure fluid problems in complicated duct.

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A methodology for fatigue life prediction of rolling contact fatigue (RCF) crack initiation on railhead was developed. It consists of finite element analyses (FEA), multi-axial fatigue crack initiation models with critical plane approach and fatigue damage accumulation. In simulations, both the global track response and the three-dimensional local elastic-plastic material response caused by the wheel-rail rolling-sliding contact were taking into consideration. It used real train traffic situations in curved sections of Shinkansen site where head checks initiate on the gauge corner of the railhead. The results from the numerical analyses were compared with observations made at the sections.

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Recently, several Meshfree methods have been dveloped. Especially, many researchers are focused on extend finite element method (X-FEM) that enables to evaluate stress intensty factors and solve crack growth problems efficiently in the area of fracture mechanics. This paper describes formulaiton of Hermitian Type 3-node Triangular Element.Then, apply Hermitian Type 3-node Triangular Element to X-FEM. Specifically, we considered to obtain appropriate solutions for two dimension elasic problems.

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The finite element method program becomes multifunctional as the computational mechanics technique develops, and it will be necessary to add more functions according to the progress of the research in the future. Naturally, it is not possible to correspond to the function addition of the kind of not assumed at first, though the possibility of the function addition is necessary to consider in any program. The use of the design pattern is advanced to correspond to more complex programming, though object-oriented approach is paid attention for more flexible programming. Here, the outline and directions of the Option pattern designed for the FEM program enhancing are demonstrated.

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We report Monte Calro simulation data of models for membranes of torus, spherical, and hexagonal shape. The models are defined by the bond potential and a constraint potential. We find that the models undergo a phase transition between the smooth phase and the collapsed phase just like the curvature surface models.

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We study a surface model for membranes by using the flat histogram Monte Carlo (FHMC) simulation technique. FHMC technique is known as useful for simulations of first-order transitions such as the ferromagnetic transition seen in the statistical mechanical models. We show in this presentation that FHMC simulations reconfirm the first-order nature of the transitions of the surface model, which was already reported to have first-order collapsing transition and a first-order transition of surface fluctuations by using the canonical MC simulation technique.

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We study the relationship between lattice mismatch and adhesion strength of interfaces between organic materials and metals by using molecular dynamics. Aromatic resins with benzene-ring connected structures are used as examples of organic materials. We define a lattice constant of the aromatic resins as the distance between the second nearest neighbors of a benzene ring. The value of the lattice constant of a wholly aromatic polyester resin is about 0.24 nm. On the other hand, a lattice constant of face-centered-cubic structured metals is defined as the distance between the nearest neighbors. The values of copper and silver are about 0.255 nm and 0.29 nm, respectively. The adhesion of aromatic polyester resin with copper is stronger than that with silver because the lattice mismatch of the resin with copper is smaller than that with silver. Reducing the lattice mismatch is found to be effective in strengthening the adhesion.

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Graphene is a two-dimensional carbon sheet in which the mobility of electrons is extraordinarily high. In this study, the stable structures, electron density distributions, and band structures of graphene sheets with Stone-Wales defects or stressed graphene sheets are calculated using first-principles calculations. The differences between the electronic characteristics of unstressed and stressed graphens are discussed.

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Coalescence of two metallic clusters of different elements is studied using molecular-dynamics simulation. All the pair combinations among the six elements Ni, Cu, Au, Ag, Pt, and Pd are considered. The final structures of united bimetallic clusters are classified into the three categories, epitaxial, core-shell, and alloyed. Which type of structure appears via coalescence depends on the size and temperature of clusters, that can be summarized in phase diagrams.

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Since the melting point or bulk modulus of nanoparticles (NPs) varies with the change of their size, the mechanical properties of NPs attract much attention. The molecular-dynamics simulations of uniaxial compression of silicon NPs are performed using the Erhart potential. A SiNP is pinched by parallel rigid plates of diamond as indenters. The indenters are forced to a target position within the SiNP and then reversed. As multiple compression cycles progress, irreversible deformation of the SiNP is observed.

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The objective of the present study is to predict the time transition of CO_2 hydrate film thickness by the analysis. The model is developed based on the mass transport mechanism. The model is based on the hydrate formation and dissolution behavior. In the present model, hydrate formation occurs at the interface between liquid CO_2 and hydrate due to the penetration of H_2O molecules through the CO_2 hydrate film. Meanwhile hydrate dissolution occurs at the interface between water and hydrate due to the diffusion of CO_2 molecules to the water phase. The estimated diffusion coefficient of H_2O molecules as 3.1×10^<-12> m^2/s is used to the model calculation. The results indicate that the film thickness decreases within several minutes, then increases.

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Subcooled flow boiling of water and aqueous solution of ethanol has been investigated in horizontal mini and micro channels. Tested fluids are water and aqueous solution of 10 and 50 wt% of ethanol. Mini-sized channel is 140mm in length, 1mm in height and 1mm in width, and micro-channel is 290mm in length, 0.5mm in height and 0.7mm in width. Copper heating surface of 1mm × 10mm is placed at the bottom of mini-sized channel and that of 0.5mm × 10mm is used for the micro-channel. The tested liquid subcooling is 40K at atmospheric condition and the liquid velocity is 0.15〜1.0 m/s in mini-channel .and 0.3〜0.5m/s in mini-channel. Microbubble emission boiling occurs in transition boiling and the heat fluxes increase higher than the ordinary critical heat fluxes for the channels.

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In highly-subcooled boiling, microbubble emitted from coalescing bubbles formed on the heating surface and the heat flux increases higher than the ordinary critical heat flux. This boiling regime is called microbubble emission boiling (MEB). In this study, the effect of ultrasonic wave on the MEB have been investigated in subcooled quasi-pool boiling condition for an upward flat copper heating surface of 10 mm in diameter. The liquid subcooling is kept at 15, 20, 25, 30K and the liquid is the aqueous solution of ethanol of 0, 10, 50 wt%. The high speed video imaging system is employed to observe the bubble behaviors on the heating surface. In the case of liquid subcooling of 20K without ultrasonic wave, no MEB occurs and it turns to film boiling immediately even if MEB occurred. On the other hand, in the case liquid subcooling of 20K and 25K with ultrasonic wave, the large coalescing bubbles are collapsed to many microbubbles and the heat flux increases surprisingly higher than the critical heat flux. Therefore, Heat transfer enhancement is remarkably introduced in the subcooled pool boiling with ultrasonic wave at liquid subcooling of 20K.

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This study focuses on the improvement of hydrosphere environment for firefly using micro bubble. The fundamental characteristics of micro bubble are investigated toward the depollution of water in hydrosphere environment for firefly. A series of measurements of micro bubble are carried out with changing flow rates of air and water. After generating micro bubbles, the particle size and the number density are measured. At the same time, the transient change of DO value and pH value are measured. It is realized that the effect of water flow rate on the physical characteristics of micro bubble is larger than that of air flow rate. In case of cavitation method, the water with micro bubbles is maintained neutrality. In case of gas-liquid mixing shear method, the water with micro bubbles is slightly alkalified. The value of DO significantly increases after generating micro bubbles.

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This paper describes the behavior of thermal plumes from three block-type heated sections in an enclosure. The temperature distribution and flow situation were obtained numerically by solving two-dimensional unsteady governing equations for Gr=3.92×10^7, block pitchs Pi=50〜100[mm], and Pr=171.1. Thermal plumes from each block are unified each other near the center block in transient process. After that it goes up and impinges to the upper wall as if it is one thermal plume. Two-large recirculation flows are generated in an enclosure. Local Nusselt numbers on the heated blocks and the effect of block-pitch were also evaluated.

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This paper describes the heat transfer characteristics of impinging jet on heated impingement surface with several blocks set in zigzag arrangement in a comparatively narrow space with confined wall. The velocity vectors, isothermal lines and Nusselt number distribution were obtained numerically by solving three-dimensional governing equations for the Reynolds number Re=1500, the dimensionless space H/D=0.67, a side of a block=10[mm] and the horizontal and vertical pitch 20 and 40[mm], respectively. The effective area is not remarkably affected by nozzle position. The unique distribution of the local heat transfer is obtained on the area beneath the nozzle corresponding to the flow situation The heat transfer on the block surface is improved on the upstream side.

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The transient flow and heat transfer characteristics of the mixed convection in a horizontal square duct with heated walls are examined numerically in three-dimensional system. The SIMPLE procedure and QUICK scheme are applied to solve the governing equations through a control volume. The working fluid is water, and the temperature dependence of kinetic viscosity v and thermal conductivity λ of water is considered in this analysis. Numerical results show that the reverse flow and the spiral flow flows appear on the upper wall and along the flow direction, respectively. The local Nusselt numbers are presented from the starting point of the heat transfer to the exit corresponding to the transient flow behavior.

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This study is to investigate an effect of natural convection on mixing processes by molecular diffusion in a vertical stable stratified fluid layer consisting of two component gases. There are many experiments and analyses regarding natural convection in a vertical fluid layer. However, there are few studies on natural convection and molecular diffusion in the vertical stable stratified fluid layer consisting of two component gases. The experiment has been performed regarding the combined phenomena of molecular diffusion and natural convection in a reverse U-shaped passage having three vertical parallel pipes and a vertical slot filled with two component gases. The transport process of the two component gas having different density in the reverse U-shaped passage having three vertical parallel pipes was discussed in this paper.

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Time transients of pressure and mass in a liquid nitrogen tank with and without fluid depletion are experimentally examined. The amount of gas generation was calculated under a thermal equilibrium assumption. The gas generation rate is found to be constant on a stage of without fluid depletion. The gas generation rate decrease with increase of liquid mass in the tank, which tendency is different from the previous finding. In order to understand this difference, it is necessary to consider a subcooling of the liquid phase. In an early stage of fluid depletion, the gas generation rate indicates a large value which is around ten times of that obtained in the stage of without fluid depletion.

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Two-phase flow boiling heat transfer of water in a horizontal small diameter tube, ID=0.9 mm, was experimentally examined at an atmospheric pressure condition in a range of mass flux from 120 to 360 kg/m^2s. Predicted pressure drop was within an error of 30%, when a critical Reynolds number is selected to be 3000. However, more adequate model for calculating acceleration loss is necessary to make better pressure drop prediction at a higher heat flux. The effect of mass flux and location on the heat transfer coefficient was small. CHF can be predicted within an error of 20% by the Katto's correlation.

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Heat transfer characteristics of a newly developed heat storage material were experimentally studied. Paraffin wax of melting temperature of 23℃ was used as the PCM (Phase Change Material).The PCM was inserted into a carbon sheets using the industrial chemical reaction processes. The heat storage materials combined and made a heat storage apparatus. This apparatus inlet and outlet temperature profiles were measured both heating and cooling processes. It was found that melting speed is faster than freezing speed.

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As one of the environment problems, heat island problem becomes serious owing to the concentration of population and industry in big cities around the world. Therefore, in this study, we focused on a heat shield paint, which can reduce thermal storage in a concrete building under solar heating. But, the heat shield paint might cause the increase of heating load to building in winter. We therefore combine the, heat shield paint with an external insulating building with vent layer to evaluate the effect of the green technology for urban area.

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The controllability of external thermal insulation building with vent layer was investigated numerically and empirically. At first, the heat transfer and fluid flow of a fundamental flow system were analyzed to confirm the applicability of the present numerical computation. The visualized wall temperature pattern by infrared thermography was compared with the numerical simulation, and the validity of the numerical simulation was also verified. The Optimum vent layer size, optimum thermal insulation thickness and optimum flow rate were considered along with developing the technique how to control the present thermal system by switching the vent.

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The analysis of compressible multi-phase flow in generic code is difficult to analyze compressible multi-phase flow. And so, this paper aim to remagine new algorithm for analysis of compressible multi-phase flow. As new algorithm, we are used as reference to implicit iterative algorithm in HSMAC method.

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This study is concerned with extension of numerical code called CRIMSON (Civa Refined Multiphase SimulatiON), which has been developed to evaluate multi-phase flow behaviors based on the recent CFD (computational fluid dynamics) techniques. The CRIMSON employs a finite-volume method combined with the high order interpolation scheme, CIVA (cubic-interpolation with area/volume coordinates). The CRIMSON solves gas-liquid two phases by a unified scheme of CUP (combined unified procedure). The conventional CIVA method has a problem of loosing interface sharpness in long-term calculation. In this study, the problem was solved by introducing the idea of the phase field method. For numerical analyzing splashing fluid, we also introduced the SPH particle method to the CRIMSON.

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The fuel spray of automobile engine includes multi-scale free surfaces; a liquid film forms at the fuel injector outlet, and then the liquid film breaks up into droplets. To simulate multi-scale free surfaces, we combined a particle method and a Cartesian grid method. The liquid film breakup near the injector outlet was simulated using the particle method, and the air/fuel mixture after the liquid film breakup was simulated using the Cartesian grid method. Distributions of droplet diameters and velocities, calculated in liquid-film breakup simulation, were used as an initial condition of spray for the Cartesian grid method. We applied our new method to simulate a collision fuel injector. The simulation results were compared with the measurements. The liquid film breakup near the injector outlet and the behavior of the air/fuel mixture qualitatively agreed with the measurements.

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A numerical method adopting a diffuse-interface model (DIM) is applied to interface-tracking simulation of microscopic incompressible two-phase flows with a high density ratio on a solid surface. The DIM is based on the free-energy approach. In the flows, the physical properties vary steeply but continuously across a finite volumetric zone, which is assumed as a fluid-fluid interface between the phases. The wettability of a solid surface is taken into account through a simple boundary condition derived from the increase in free energy on the surface. The DIM approach simplifies the capture of motions of a fluid interface on the surface (contact line). The method solves a set of the Navier-Stokes equations and an advection-diffusion equation for the fluid volume and interface. The numerical results of two- and three-dimensional static and dynamic contact-line problems prove that the DIM-based method can be employed for simulating the two-phase flows in MEMS-device manufacturing processes.

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The three-dimensional two-fluid model analysis code ACE-3D was applied to the boiling two-phase flow analysis in 37 rods tight lattice fuel bundle geometry. It was confirmed that the computation result shows qualitatively agreement with the pressure loss by past experiment.

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