The applicability of a numerical method is preliminarily examined to determine its suitability for simulations of microscopic immiscible liquid-liquid motion on solid walls with textured surfaces, which is used for evaluating flexible large-area fluidic devices and a novel screen printing process. In the method, a conservation-modified Allen-Cahn equation is adopted for calculations of diffuse-interface advection and formation based on a phase-field model, and a lattice-Boltzmann method is employed as numerical scheme for solving the two-phase fluid-dynamics equations. The simulations demonstrate the ability of the method to successfully capture the shape and motion of a droplet, not only in a liquid flow inside a rectangular micro channel with linearly grooved wall, but also on wettable parallel-wall structured surface under capillary force.

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We have been developing a compact and low-cost, but flexible wave power generator responding to multi-degree-of-freedom motion. In this study, we optimize the electromagnetic mechanism, especially the properties of coils in the device, for efficiently generating electricity. For the pupose, we perform the electromagnetic field analysis and validate the numerical results through some experiments.

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Cavitation generated by ultrasonic wave can be utilized in various situations such as medical and industrial. However, the cavitation damages machine materials itself, and the debris could contaminate the sample. From the past studies, it is found that the flow field can prevent the problem. In this study, we make clear why the flow can reduce the cavitation through numerical analyses with our original CFD code.

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Currently, with the development of computational mechanics field, it has produced a new analysis methods and function. However, when you try to add these functions without thinking at all, bugs are caused by the interference of the function with each other. So, proposed the Option design pattern so that you can add these functions safely and simply. In this study, the Option pattern is applied to the base of the Finite Element Method (FEM) program. And, evaluate the effectiveness of Option pattern by addressing the function additional the eXtended Finite Element Method (XFEM) in cracks in this program.

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To develop a numerical simulation system for leaked hydrogen gas behavior, we compared calculated results by some calculation methods and time histories of hydrogen gas concentration at seven sensor positions of leaking hydrogen gas in a half-size Hallway model experimental test. The calculated results show good agreement with experimental results. Depending on the calculation method, some effect is shown.

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Fluid noise is what always happens in the windmill. Therefore, the purpose of this study is to analyze the fluid noise induced in the airfoil around by numerical simulation. Turbulence model used in the numerical simulation is the LES model, acoustic model is the FW-H model. The Calculation target is the cylinder and the airfoil for windmill. Characteristics of the fluid noise is revealed by the FFT analysis and the wavelet analysis.

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In piping design of nuclear power plant, if piping pass through buildings, piping design considers relative displacement for seismic. In this case, piping needs to bend to reduce effect of relative displacement. However, in case of piping pass through a tunnel, piping cannot have big bending curve. So, the case of piping pass through a tunnel is severe condition for piping design. In this paper, to establish efficient design method of piping pass through a tunnel in nuclear power plant, numerical analysis was performed. Also, to reduce effect of relative displacement, stiffness of piping was investigated. Then, computed optimal bending length was proposed and bending effect for piping perpendicular stiffness was investigated. From these results, standard piping design flow of inside tunnel was established.

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The purpose of this study is to establish an evaluation method for the buckling by the bending of a cylindrical shell using an FEM (Finite Element Method). The cylindrical shell for the evaluation is assumed to receive a bending load like a cantilever. Damage pattern is either yield state at the entire cross-section or buckling. Thick cylinder actually does not lead to buckling. However applying the traditional empirical formula for such a thick cylinder, there is a case where buckling load is evaluated lower than that of the entire cross-sectional yield load. When applying the FEM analysis to the buckling phenomena, it is necessary to carefully create the analysis model in order to accurately represent the actual phenomena. Therefore in this study, both the FEM and the experiment were performed. Two cylindrical shells with different thicknesses were used. One is led to the elephant-foot buckling , the other is led to the entire cross-section yield state. The relationship between loads and displacements were evaluated. The comparison of the experiment and the analysis is in good agreement.

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In this research, a finite element (FE) model for soft material using non-linear spring elements has been developed to simulate the large compressive deformation of thin soft material, namely rubber, and improve the convergence performance of FE analysis. In order to discuss the validation of this model, the compression experiments using rubber were executed and the load-displacement relationships were measured. These experiments were modelled and simulated by FE analysis using non-linear spring elements. In comparison with experiments and simulations, it was confirmed that the load-displacement relationships were good agreement.

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The focus of this study is to clarify effects of interface edge condition in Metal side on the bonding strength of ceramic to metal joint. Geometrical interface shape at the edge of the interface is characterized by edge angle in both sides of the ceramic and metal defined as a configuration angle between the free surface and the interface. As the edge angle of Si₃N₄ is right angle, the edge angle of Ni is set over 30°≤_φ2≤180°. Experimental results showed that maximum tensile bonding strength was observed at the edge angles of _φ2=135°. It seems that this geometrical condition is critical conditions of the bonding strength and fracture patterns. Setting near_φ2=135° improves the bonding strength since it decreases the residual stress near the edge of the interface on ceramic side. This paper provides a useful geometrical interface shape to improve tensile bonding strength of ceramic to metal joint.

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Last few decades, the crack identification in a structure is the most important problem in securing safety. In this paper, a method for determination of the location and the depth of a transverse surface crack in beams with rectangular cross section is proposed. Formulating the identification as an inverse problem, we have employed both a response surface method and changes in natural frequencies. In the analysis, the crack is simulated by an equivalent rotational spring, connecting the two segments of the beam. Analysis of this approximate model leads to a frequency equation which relates the natural frequencies to the crack location and the depth. Identification of the crack location and the depth is formulated to minimizing an evaluation function, square sum of frequency residuals. The simulated results indicate that the proposed method is valid and practical.

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If a crack exists in a mechanical structure, it may cause a serious accident. To prevent the accident, the early crack detection is crucially important. In this paper, a method for determination of the location and the depth of a transverse surface crack in a shaft is proposed. The study, which is treated as an inverse problem, was performed using both a response surface method and changes in natural frequencies. The natural frequencies are then represented as functions of the crack location and the crack depth. Using these functions, identification of the crack location and the crack depth is formulated to minimizing an evaluation function, square sum of frequency residuals. The simulated results indicate that the proposed method is valid and practical.

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The bamboo is distributed throughout Southeast Asia and it has been widely used in our daily life through centuries. On the other hand, the bamboo has attracted increasing interest for its durable property from the point of view of bio-mimicking. It is well known that the bundle sheath is nearly 10 times stronger than the bamboo matrix. Observing the cross-section of the bamboo, we can see that the density of the bundle sheath has a gradual change from the inner surface to the outer one (See Fig. 1). This means that the bamboo get more and more stronger toward the outer surface. Hence, the distribution of the bundle sheath give the bamboo superior mechanical properties. This is considered to be a result of adopting to the environment. In this paper, using the concept of functionally graded materials (FGMs), we analyze mechanical properties of the bundle sheath. In the analysis, we employ the simple beam theory and the three dimensional finite element method (3D-FEM) and we compare the analyzed results with experimental ones.

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In this paper, experimental and theoretical investigations were conducted to evaluate the axial force of a hook bolt, which is used for clamping a sleeper and a railway track. After fastening the hook bolt, we applied a transverse load which simulates the train wheel passage over the sleeper using a screw jack. The axial force is determined from three strain gauge output data employing the least square method. It was found that the axial force decreases by 2.3% when the train simulating load was applied. Experiment results indicate that U-shaped plate have a great influence on the axial force of the hook bolt.

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A buckling coefficient estimation method without buckling tests or simulations for hollow extrusions is proposed. The buckling coefficient for plates constituting hollow extrusions is related to the support stiffness for plates joined at both ends of the buckling plates. Thus, by using a model with a buckling beam and a jointed beam, the relational expression between angle and moment was derived, and then the support stiffness of the jointed plate was obtained. Next, buckling analyses were executed under the conditions of various support stiffnesses for the jointed plates, and then an approximate function between the support stiffness and the buckling coefficient was derived. This function was applied to multi-jointed plates and asymmetric jointed plates, and was compared with the analysis results. It was then found that the buckling coefficients obtained from the function matched those of analysis results.

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Although fuel debris containing hard boron carbide (B₄C) control-rods should be securely removed and kept from three reactors at Fukushima Daiichi nuclear power station, owing to high-dose radiation we have no information of the debris’ properties required to develop cutting tools. In the present study, we aim to establish a nanoindentation application measuring the mechanical properties of fuel debris which have sample size of sub-millimeters. We examined how surface polishing process and sample size affect on mechanical properties measurement of the B₄C particles embedded in epoxy resin. While 1mm B₄C particles polished with #240 abrasive paper had elastic modulus and hardness which were practically close to those from a literature at errors of 1.6% and 9.1%, those values of 100μm particles polished with #1500 paper were significantly lower even in the modulus at a factor of 46%. We conclude that the lowered mechanical properties in the 100μm particles were caused by the inclined sample surface made by the insufficient surface polishing process.

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Although isostatic pressing is an effective method to densify low-molecular-weight organic semiconducting films (OSFs), the application for polymeric OSFs has never been examined. In the present study we optimized coating conditions of polymethylmethacrylate (PMMA) films and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) films coated on glass substrates by both drop-casting and spin-coating methods, and examined cold isostatic pressing (CIP) behavior of the films. The drop-cast and spin-coat PMMA films were effectively densified using the CIP process by factors of 56% and 63% respectively. Additionally the pressed drop-cast PMMA films were hardened by 5.7 times. However there was no change between the drop-cast PEDOT/PSS films before and after the CIP process in terms of film thickness and hardness, indicating the process didn’t effectively work to improve the density of the films.

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In order to discuss the effect of the test load on damping hardness of Herbert hardness test, we carried out the Herbert hardness test for the metals using 2 kinds of the Herbert pendulum hardness testers with various weights. Correlation between damping factor (damping hardness) and the weight of the tester cannot be observed although rolling resistance of the columnar indenter of the tester is supposed to be in proportion to test load. For some metals, the damping hardness of lightweight Herbert hardness tester is higher than that of heavyweight Herbert hardness tester. These results indicate that damping hardness is affected by not only the strength of the specimen surface but also damping characteristics and micro structure of the specimen.

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The purpose of this study is to investigate the basic hydrodynamic behavior by performing experiments down burst phenomenon in the laboratory. In order to reproduce the down burst phenomenon, we produced the perpendicular down flow based on the density difference, and examined a flow down characteristics about a liquid and gas.

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Currently, it has attracted attention as a means of ground heat pump system that utilizes renewable energy solution to energy problems. Elucidation of the thermal response of the soil in order to improve system performance is very important. Analytically reveal the thermal response of the soil by using a small-scale experimental apparatus in this experiment.

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This study is concerned about the thermal response of the soil. Dry river sand are prepared and the pipe inserted in the soil. The heated water is circulated through with constant flow quantity in the pipe. The position to measure is distance from a pipe L=20mm and three different depth H=100,400,850mm from topsoil. The characteristic of the thermal response by the different soil was confirmed.

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Measurements of ammonia (NH₃) in automobile exhaust is required, because NH₃ contributes to the secondary formation of particulate matters. However, there are few devices which can measure the NH₃ emission from automobiles in the real-world. Therefore, we developed a portable NH₃ measurement device using laser absorption spectroscopy with an Astigmatic Herriott cell. We also demonstrated NH₃ measurements in exhaust emitted from a gasoline vehicle using the developed device.

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Static gravimetric method with flying start-and-finish is widely used for calibration of large and medium liquid flow for its advantage of maintaining continuous flow through the flowmeter. However one needs to take certain considerations in implementing this method in small flow systems to obtain good accuracy. At NMIJ/AIST, we adopted this calibration method for small hydrocarbon flow facility using a newly designed diverting system - a cone-shaped rotating double-wing diverter - for flow range between 1 L/h~100 L/h. This paper describes the design features and operation of the diverting system, and also discusses the timing error of the diverting system evaluated according to ISO4185.

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The flow state that a gas to rise in the vertical tube and a liquid flowing down is called countercurrent flow. This study is intended to clarify relations with pressure fluctuations in lower plenum and the air flow rate, as well as the liquid flow rate and the air flow rate. We performed an experiment that used multi narrow tubes of 1mm diameter. From the experiment, we clarified that countercurrent does not happen in narrow tube of 1mm.In addition the volume of pressure in the lower plenum depends on the air flow rate and number of the air tubes. The quantity of liquid flowing down depends on this pressure. It is limited by volume of pressure in the lower plenum.

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The flow rate of the primary coolant system in natural circulation decay heat removal operation is reduced much lower than that in rated operation in Next generation sodium-cooled fast reactor. The electromagnetic flow meters which are applied to sodium circulation loop have uncertainty on the indicated value at low flow rates conditions． Ensuring the measurement accuracy of electromagnetic flow meter is presumed to contribute the promotion of understanding of thermal hydraulics phenomena such as natural circulation in the fast reactor． Ensure the evaluation accuracy may also contribute the safety enhancement of fast reactors. In this paper, low flow rate evaluation method has been examined preliminarily by transport time-delay analysis of temperature fluctuation in sodium circulation loop. Measured data and evaluation results from temperature fluctuations which have been acquired in sodium-loop in AtheNa, indicate that this evaluation method can be applied to estimate flow rate in natural circulation decay heat removal operation.

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This study is concerned about interaction property of neighboring bubbles formed from a nozzle. The interaction of neighboring bubbles is known to become the important factor to decide heat transfer properties at the nuclear boiling. It is intended that we evaluate influence of the interaction of neighboring bubbles by comparing the behavior of bubbles generated from the twin nozzle with the bubbles generated from single nozzle. From this experiment, we clarified that twin nozzle has critical flow rate. Under the critical flow rate, bubbles are generated from a unilateral nozzle and over the critical flow rate, bubbles are generated from both nozzles.

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The present study focused on the environmental pollution due to the radioactive material, and investigated the spatial distribution of radiation levels, concentration and depth distribution of radioactive material in the soil. Radiation level of five subjects are monitored, and the result showed that the radiation level is 0.60mSv/YR in 2015. Concentration of radioactive cesium in the soil of Hitachi campus (Ibaraki University) is monitored, and the result showed that the concentration of radioactive cesium is maximum near the surface and reduce exponentially with depth direction.

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Accurate evaluation of three-dimensional temperature distribution is essentially required for the structural integrity analysis of large-sized straight tube steam generator (SG) of an advanced Sodium-cooled Fast Reactor (SFR). Numerical simulation system to analyze three-dimensional thermal-hydraulics in the straight tube SG has been developed. The three-dimensional simulation on sodium side by the CFD code FLUENT with porous body model was coupled with the multi-channel simulation on water/steam side. Synthetic numerical simulation model of the SG including inlet and outlet plenums were constructed. Through the numerical simulation at the condition with plugged tubes, the characteristic three-dimensional distributions of velocity in the plenum and temperature distribution in the tube bundle were successfully analyzed.

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This study investigated several stochastic geometry treatments for the coated fuel particles (CFPs) in the high temperature engineering test reactor (HTTR) fuel compact. The criticality calculations were carried out by using MCNP5 for a single fuel block with reflecting boundary condition. The infinite multiplication factor (k_inf) of these random arrangements was about 0.03% – 0.15% difference compared to that of regular (uniform) arrangement. The random packing CFPs in an annular lattice showed the highest k_inf due to non-truncated CFPs in this model.

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An experimental investigation was performed for a pulp suspension flow in a channel with a partition plate, which is an extremely simplified model of the dispersion and rectifying parts of the hydraulic headbox of papermaking machines. Flow visualization and optical measurements of the fiber concentration were performed in the wake of the inserted flat plate. Characteristics of the pulp liquid flow were examined for five flow cases based on the flow patterns found in the author’s previous report (2013) for a duct. A discussion is given on the change in the distributions of the time-averaged and fluctuating fiber concentrations in the wake along the stream direction. Furthermore, the effects of the flow velocity on these distributions are clarified.

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In this study, the behavior of the autoignition in a supercharged SI engine was investigated by using light emission and absorption spectroscopic measurements. Spectroscopic measurements were applied to investigate the behavior of formaldehyde (HCHO) and OH radicals in the interval from the occurrence of a cool flame to autoignition. As a result, formaldehyde arose in cool flame reaction and consumed at main combustion. In addition, OH radicals arose at the time of knocking.

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The cylinder temperature and pressure of turbocharged engines were simulated in a constant volume vessel, and supercritical DME spray was observed with a high-speed camera. Parallel light shadow graph was used to image gas-phase spray and diffuse light shadow graph was applied to image liquid spray. The spray shape and the development process at temperatures below and above the critical point was investigated. The results show that there is no significant difference in spray shape between supercritical spray and subcritical spray. Penetration length of supercritical spray is almost same as that of subcritical spray, while the supercritical spray evaporates faster than the subcritial spray because it has higher enthalpy.

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Ethanol has the same theoretical air fuel ratio as DME and different ignition characteristics. In this study, effects of ethanol blending on ignition and air entrainment of DME spray were investigated by high speed observation of the spray in a constant volume vessel. Overall equivalence ratio in sprays at ignition timing were calculated from the observed pictures based on momentum theory assuming quasi-steady state. As the results, ignition timing was delayed and the overall equivalence ratio was reduced when ethanol was blended into DME.

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We generally define flammability limits by using a one-dimensionally propagating flame confined in a special burner developed in United States Bureau of Mines. But it is difficult to make absolutely the same equipment in laboratories. On the other hand, tubular flame is easy to be formed and it has quasi-one-dimensional character. We conducted numerical calculations with a radiation model and determined diluent limits of various flames of a low-grade fuel; fuel mixture of CO₂ and CH₄, and that of N₂ and CH₄. As a result, we found that the method of deriving diluent limits by using tubular flames is valid as a measuring method alternative to the one-dimensionally propagating flames. In addition, we conducted experiments with a swirling type tubular flame burner, and revealed that swirling type tubular flame has diluent limits relatively close to that of the porous cylinder type tubular flame obtained by Liao et al..

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Al-Cu-Mg base 2024 alloy has high strength and high elongation, and is widely used in airplanes, cars, etc. According to the previous researches, the strength of 2024 alloy is drastically increased by grain refinement. High-Pressure Torsion, HPT, is one of typical processes of severe plastic deformation, and is very effective method to reduce grain size. It has been reported that HPT process improves mechanical property of 2024 alloy to have nearly double hardness of conventionally processed 2024 alloy. In this study, mechanical properties of cold rolled 2024 alloy was investigated to obtain experimental information on the effect of cold working on the strengthening mechanism. Vicker’s hardness of the specimen cold rolled by 90 % reaches about 200, which is higher than the hardness value in the peak-aged specimen of 2024 alloy.

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In recent years, it is studied about the fatigue characteristics of the aluminum alloy. The aluminum alloy which is nonferrous metal materials doesn't usually have the clear fatigue limit. But it was found that 5056-H112 aluminum alloy has the fatigue limit. The research shows that the aluminum alloy which exhibits significant work hardening and strain aging has a high possibility of the fatigue limit. So the study which adds a large quantity of Mg to the aluminum alloy which doesn't indicate strain aging and gives strain aging is also performed for the purpose of making the fatigue limit. Therefore, in this study, effects of solid solution magnesium on fatigue characteristics in Al-10%Mg alloy which added a large quantity of Mg to 5083 alloy is investigated.

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Spinning is a forming method which forms the flat disk metal into cylindrical metal．Spinning is also used to neck-form the tube end，such as the high-pressure hydrogen storage container．The 6061 aluminum alloy is used as liner material of the high-pressure hydrogen storage container．The tube end of aluminum alloy liner is neck-formed by spinning without forming die．In this case，there is an issue that the forming defect may be introduced at the inner surface of container after neck-forming．It is considered that the forming defect is suppressed by spinning with forming die．However，the effect of forming die on spinning workability of aluminums is not reported．In this study，the spinning workability of aluminums with or without forming die is investigated，and the mechanisms of the occurrence of the forming defect are discussed.

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It is possible to get the various special properties by adding alloying elements to titanium. Gum Metal is a titanium base alloy developed to achieve low Young’s modulus similar to cortical bones. When the alloy is cold worked, it shows the special mechanical and physical properties different from ordinary metallic materials. It has been thought that this phenomenon is related to unique deformation mechanism of Gum Metal. In the present study, influence of the loading conditions on mechanical response during nanoindentation was investigated for the purpose of analyzing the unique deformation mechanism.

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Residual stress induced by large amount of drawing deformation sometimes decrease a toughness and strength of drawn wire. However, low temperature approximately 450 ℃ annealing after drawing improve mechanical property. In the present study, influence of drawing and low temperature annealing on residual stresses is discussed in in drawn wire of stainless steels.

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Anisotropic strain age hardening behavior affected by pre-strain direction was found in the low carbon ferritic steel. The stress carve of specimens along the pre-strain direction show discontinuous yielding behavior while ones of orthogonal direction show continuous yield behavior. In order to discuss the reason of anisotropic behavior, the neutron diffraction measurements were performed. As a result, role of internal grain stress was discussed.

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By recent technical improvement, it is not only important to understand the amount of defect but also dispersion, morphology and the position of microstructure. In this study, AC4CH cast aluminum alloy was observed and 3D microstructure was built by using Serial Sectioning to know the result of microstructure states.

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Hardness of sand mold is decreased at the periphery of the casting by the pouring, however, a part of range is hardened. Understanding distribution of hardness and resin density lead to be determine the amount of minimum resin to satisfy necessary strength. In the present study, measuring sand molds hardness at the time of the before and after pouring of aluminum alloy casting, and investigated sand molds inhomogeneity.

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Bending a steel plate to 180 °, make the hemming. Hemming is a method of joining by folding the outer panel and the inner panel. It is used for automobile door. Moreover, safety is improved by bending the cut surface of the metal plate on the inside. Hemming is three steps of the flange bending, pre-bending and hemming. In hemming may shape defects occur. Therefore, it is necessary to select the best bend angle, FEM analysis is valid. However, fewer cases could accurately analyze the bending of the thin plate to date. In this study, to clarify the occurrence conditions of the shape defect was investigated analyzing method for performing high precision analysis.

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In recent years, high-precision hem processing is required in automobile manufacturing. For the work of the plane straight edge shape in the present study, to change the flange angle and pre-hemming angle performs a 180° bending experiment, it was investigated the influence and defect conditions on the product shape after the bending. Buckling of the flanges occurs when pre-hemming angle of more than 80°, it produces a growing or warp on work. Buckling of the flanges appear to load data. Pre-hemming and the bending in, the more bend in the growing side large contact angle of the blade and the flange of per process, a smaller creepage side. Recoil occurs mainly in the flange angle is large conditions.

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This paper describes a production process for experiment and finite element method (FEM) analysis of cold forming of SUS304 pipe. These large diameter pipes such as φ114.3 mm are used for a plant as a flow channel of gas and liquid. The connection of pipes are generally welded at the plant. However, the other connecting method are required from a viewpoint of making the plant environment worse by welding. Therefore, flaring process of large diameter pipes were proposed. This flaring process is one of a method of pipe flange forming. The formed pipes were connected used with loose flange. Flaring process was generally hot process, thus it has some problem such as becoming complex of forming machine and accuracy of dimension. In this study, cold flaring process of SUS304 pipe was proposed to satisfy these requisitions. Experiment and FEM analysis of cold flaring process were performed to clarify the optimum forming conditions for the flat length of connecting surface such as a diameter of punch, punch stroke and taper angle of dies. As a result, a gap between punch and die was needed to match the pipe wall thickness. In addition, optimum taper angle of die for flat surface was 1.0 degree.

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Magnesium alloys, the lightest practical metallic material, is attractive while energy-saving society is strongly expected to overcome the environmental problems. The crystal structure of magnesium alloys is hexagonal close-packed, so they have poor workability. It is known that the strength of magnesium alloys strongly depends on the size of crystal grain, which is also related to their crystal structure . However, the factors affecting the strength of magnesium alloys have not fully understood. In this study, the effect of grain size on the mechanical properties of AZ80 magnesium alloy was studied. Specimens with various grain size were prepared by heat treatment after high-pressure torsion, HPT, which is known to be very effective process to reduce grain size.

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This paper describes a vertical type twin roll strip casting process for producing aluminum alloy strip of ADC12, A3003 and A7075. Twin roll casting process is able to produce a strip from molten metal directly. Thus this process has a possibility to reduce total cost of sheet making comparing to conventional rolling process. Aluminum alloy ADC12 is a casting material that is used for die casting, therefore it has an excellent castability. Aluminum alloy A3003 is known as a wrought aluminum alloy for aluminum can body sheet. The A3003 sheet is generally produced by rolling, so it is effective for reducing a process cost to produce the strip by twin roll casting process. Aluminum alloy A7075 has high tensile strength, and it is known as a material for aerospace application. The sheet is manufactured in small quantities comparing to the other sheet aluminum alloy. Because A7075 alloy sheet is generally needed to a number of rolling and annealing process after hot extrusion. It is supposed that the demand of high tensile strength aluminum sheet such as A7075 is going to increase for weight saving of structural material. In this study, twin roll casting experiment was performed to produce these three aluminum alloy strip in same experimental conditions. Castability, surface conditions and strip thickness were estimated. It was possible to cast these aluminum alloy strip.

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This paper describes a production process for aluminum alloy sheet metal. Direct molten metal rolling, in other words strip casting process for aluminum alloy A3003 sheet was operated. Strip casting process is able to produce the metal sheet from molten metal directly. Thus this process has possibility of improving the productivity of sheet because of shortening operation of rolling. In this study, experimental device was designed for direct molten metal rolling. Aluminum alloy A3003 was chosen. A3003 is for aluminum can body, and the sheet required the high productivity. The effect of roll speed on the produced strip surface and strip thickness. Roll speed were 1, 2 and 3 m/min. It was possible to produce A3003 strip by direct rolling at the conditions of roll speed 3 m/min, pouring temperature 700 ℃, solidification length 15 mm and nozzle exit width 15 mm. Obtained strip surface was flatten and had a metallic luster.

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The mold filling for a thin wall aluminum alloy casting in the expendable pattern casting process was investigated experimentally and theoretically. Thin wall aluminum alloy plates were cast by the EPC process. The fluidity length and melt velocity were measured. The use of thin expendable polystyrene pattern led to shorter fluidity length of melt. When the coat permeability was less than approximately 2, the fluidity length of the melt and melt velocity increased with increasing of the coat permeability. When the coat permeability was greater than approximately 2, even when the coat permeability increased, the fluidity length of the melt and melt velocity did not increase so much. The fluidity lengths were predicted by using measurement values of the melt velocity. The predicted values were in approximately agreement with experimental values.

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In recent years, fuel cell vehicles are attracting attention as a solution of environmental problems.The6061 aluminum alloy is used as the liner of a type-3 hydrogen tank, which is surrounded by CFRP. Higher-strength aluminum alloy has been developed to reduce the amount of CFRP. However, we must pay attention to hydrogen embrittlement (HE) when we apply the higher-strength aluminum alloy to the liner. The HE is observed 7075-T6 alloy when the specimen is examined in humid air by means of slow strain rate technique (SSRT) tensile test. The HE process is reported as follows: micro-cracks originate at second-phase particles on the specimen surface and then become intergranular cracking. The HE process of 6000 series aluminum alloy has not been reported yet. Therefore, in this study, we have investigated relationship hydrogen embrittlement cracking and second-phase particles by means of SSRT tensile tests in humid air and dry nitrogen gas.

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