A jet with higher stagnation pressure than a certain critical value becomes underexpanded. It is known that underexpanded jet can produce a high-frequency sound known as screech, which has been studied so far. However its mechanism has not fully explained yet. Impingement of such a jet on an object can be found in various fields in industry. Impingement on a flat plate has been much studied, but the study has been mostly focused on the jet immediately downstream of the nozzle and not the wall jet on the plate. The disturbance generated at the wall jet is very much likely to affect the main jet. Thus it is necessary to examine and discuss the flow pattern and the behavior of the wall jet for the mechanism of the screech in the main underexpanded jet. In the present study in order to simplify the flow field of wall jet downstream of the main underexpanded jet, two colliding jets under equal condition are used. The flow field is visualized with schlieren and shadow graph technique.

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Wiper is an important vehicle equipment to keep a clear view for a driver. The characteristics of the fluid flow around the blade lip of a wiper have been discussed in this study. The analytical model for the fluid flow and the governing equations for the model have been established. The governing equations have been numerically solved and the results have been compared with the analytical results. It was found that fluid flow between the blade lip and the glass can be approximated by the analytical results. It is concluded that there is a relationship between the water film thickness and the blade angle.

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The operation range of a centrifugal compressor or blower at low flow rate is limited by self-excited oscillation in the diffuser called rotating stall that causes sudden performance drop. One of the main characteristics of this phenomenon is pressure fluctuation that varies in various patterns. There is a pressure fluctuation even before the onset of rotating stall, which is weak and its intensity is not stable. In this study herein, simultaneous multiple static pressure measurements were held with pressure transducers in entire diffuser at the flow rate just before rotating stall generates. For analyzing various signal processing methods were used; continuous wavelet analysis, cross spectrum analysis and phase-locked ensemble-averaging technique. As result, aspects of the pressure field just before the onset of rotating stall is clarified.

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Numerical analysis has been performed for three-dimensional fully developed turbulent flow in a helically curved pipe by using an algebraic Reynolds stress model. It is interesting point whether the present method can predict correctly the complicated turbulent flow in helically curved pipe, or not. In the numerical calculation, an algebraic Reynolds stress model is introduced to predict correctly anisotropic turbulence. Three types of helical pipe with different torsion ratio are selected to calculate in this research. Calculated results of streamwise mean velocity, secondary flow vectors and turbulent intensity are compared with the experimental date in order to examine the validity of the presented method. As a result of this calculation, it was found that the present method could predict reasonably the streamwise velocity, i.e., the movement of maximum mean velocity from outer wall to inner wall with increasing torsion ratio is reproduced correctly by the presented method. As for the turbulent intensity, the presented method is able to predict characteristic features of its distribution qualitatively but has tendency to underestimate the experimental results.

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Numerical analysis has been performed for three-dimensional developing turbulent flow in a constricted tube by using an algebraic Reynolds stress model. It has been pointed out as a characteristic features from the experimental result that the separated flow is produced in a constricted tube by pressure gradient. The calculated results are compared with the experiment in order to confirm the validity of the presented numerical method. As a result of this calculation, it was concluded that the present method could predict streamwise velocity reasonably and reproduce the reattachment point of separated flow. As for the prediction of turbulent energy, the presented method tends to underestimate the experimental value.

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The SI-F method was suggested by Iwasaki et al, as the reasonable damage detection method. In the present method, the damages will be detected from the change of correlation between sensor output. In this method, Correlation between sensor output will be identified by using the response surface method and similarity of the correlation is tested by using statistical Ftest. However the damage detection limit to correlation strength is not verified. In this paper, the damage detection limit map is made and the detection limit of damage is verified.

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This paper proposes an inspection technique using Lamb waves to detect a disbond in a CFRP skin-stringer structure. This technique employed the pitch-catch method using two piezoelectric elements especially designed for the low-frequency Lamb A_0 mode. We measured the arrival times of the transmitted A_0 mode as a function of disbond length. A remarkable delay in the arrival time due to the disbond was detected, and its length could be calculated based on a simple model for Lamb-wave propagation. We successfully detected and evaluated the disbond using the proposed technique and confirmed its ability to inspect the skin-stringer structure.

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Non-contact detection of cumulative damage stored in composites has been carried out using microwave reflection/transmission energy. The change of these properties due to the incorporation of micro-fracture events which include matrix cracking, interface debonding etc. has been successfully obtained. The damage behavior and the changes are discussed in terms of nondestructive evaluation of composites. The present research centered on the application and use of microwaves in a non-contact method for determining the amount of fracture damage accumulated in glass fiber reinforced plastic (GFRP). It will be shown that as the damage within the GFRP increases, a change in the properties associated with the microwaves used also change, thereby giving a strong correlation between the accumulated damage within the GFRP and the microwaves used to detect that damage.

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[in Japanese]

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FRP (fiber reinforced plastics) discharged from the disused FRP boats contains glass fiber and it is very hard. Accordingly it is too difficult to crash or break it. Moreover, it causes the worker to keep FRP at a distance so that he may feel the pierced pain when the FRP mine dust adheres to his skin. Therefore, it was not thought to do the disposal process after FRP was made a powder. In this research, FRP is solidified with the binder after it is pulverized, and the method of manufacturing recycled goods for the cement burning to which the FRP mine dust does not disperse is developed. In this report, the processing of pulverizing FRP chips is described.

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In this paper, cold spray technology with a low pressure source was studied from a basic view point. Deposition tests of particle onto the substrate was conducted using a hand-made cold spray deposition device, and influence of nozzle shape, gas temperature, gas pressure, spraying period and substrate pre-heated temperature on the deposition rate were examined. As obtained results, it was found that a lot of particles could be deposited on the substrate under higher condition of gas temperature, gas pressure and the substrate temperature. In addition, a longer spraying period and shorter length of the nozzle led to high efficiency deposition in the cold spray process.

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Passengers' needs for comfort in the vehicle compartment vary to a great extent. Aiming at "lower air pressure drop," "higher deodorant," and "longer life," we have developed a cold catalyst filter for air conditioning systems. This paper will discuss the results of our studies made on the use of cold catalyst deodorant for the cabin filter of air conditioning systems, as well as the basic performance of this filter.

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We focused on hydrogen production by purple photosynthetic bacteria as a renewable energy source and development of an effective treatment method of the shochu wastewater. We aimed at the simultaneous execution of hydrogen production and shochu wastewater treatment by photosynthetic bacteria. Rodopsedomonas palustris CGA009 was grown in the culture with varying shochu wastewater concentration form 1.0% to 20%. Cell growth and evolved gas were observed in each culture. Maximum evolved gas volume of 0.261L/L-medium was observed in the culture containing 5.0% shochu wastewater. Fastest doubling time of 3.7h was observed in the culture containing 10% shochu wastewater. Hydrogen content in the evolved gas was about 60% in all cultures. Maximum removal of chemical oxygen demand (COD) of 81.8% was observed in the culture containing 1.0% shochu wastewater. Total organic carbon (TOC) decreased to about 25% compared to initial value in shochu wastewater cultures.

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Prepreg processing conditions of a polyimide (PI)-based GFRP and their effect on the tensile strength and modulus under low-pressure formation has been investigated. Formation below common pressure at 1.4MPa for PI-based FRP using an autoclave has been attempted. A wet-prepreg with the appropriate solvent retention abilities was prepared with an available poly amic-acid and glass-clothes. The preperg was heated at 373K for 2〜24h in a furnace. Four-ply-laminates on a direction of (0/90) were formed at a pressure of 0.7MPa using an autoclave. The tensile strength and modulus increase with increase in drying time of the prepreg with the fiber volume fraction of the GFRP was normalized to 60vol%. Even with the low-pressure formation, the equivalent tensile strength and elastic modulus of PI-based GFRP using the prepreg heated for periods over 10〜12h to 373K was shown beside that of common GFRP.

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Through quenching is applied for giving desired mechanical properties of manufactured engine sling adapter. Quenching technique i.e. still and stir cooling into tap water is designed for this hardening process. Computer simulation code of DEFORM-HT was used before experiment to determine optimum process parameter and to predict mechanical properties and distortion of the hardened past. By employing single heat transfer coefficient (HTC) taken from still and stirred-quenched JIS silver probe, more distorted adapter is produced under still quenching than that under stir quenching. Comparison between simulation and experiment is presented. However, zone-based surface HTC is then needed to give more accurate prediction.

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In this study, to develop large and uniform diamond deposition process using combustion flame method, diamond deposition on one dimensionally traversing Mo substrate and investigation of diamond partile appearance variation depended on deposition position were conducted. Consequently, difference of the appearance between particles of center and edge of the deposition area, which was shown in the case of fixed substrate, was existed even in case of traversing substrate. However, there was no difference of the appearance among particles deposited on the area located on the same locus of the combustion flame, that is, one dimensionally uniform diamond deposition area could be formed by traversing substrate.

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Improvement of simulation accuracy of heat treating process of steel parts is hoped for optimizing the design and heat treating condition, etc. Simple shaped specimen is often employed to verify the simulation accuracy of heat treating process. A steel helical gear with complicated shape was used to study on carburizing and quenching process of steel parts. Calculated hardness and distortion were compared with measured values. Strain distribution and microstructure distribution were analyzed from simulation result of the heat treating process.

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Thermal Barrier Coating (TBC) is fabricated by thermal spray technology. In this technology, coating particles are melted in high-temperature plasma flow, impinged and deposited continuously to a substrate surface. Since a coating layer is formed by this way, it seems that the microstructure and the mechanical properties of TBC are affected by the spray condition and high-temperature environment in service. In this study, the substrate temperature and the particle velocity of the coating particle in plasma flow as the spray condition are varied. Coefficient of thermal expansion, elastic modulus, crack length, Vickers hardness, porosity, bending strength and residual stress of the ceramic layer are measured for as-sprayed specimen. In addition, thermal exposure tests are conducted to examine influence of exposure temperature on the mechanical properties of TBC.

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High-temperature aluminaizing which is diffusion process at a temperature higher than 950℃ make a Fe-rich alloy layer. The tensile test was done for the high-temperature aluminized steels which have the Fe-rich alloy of aluminum solid soluted ferrite on the surface of carbon steel. As a result, tensile strength of aluminized steels was 1.4 times of that of the carbon steel.

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This paper provides a part of mechanical reliability of solder joints on electronic devices. This study clarifies a dependency of the surface tension in liquid lead free solder (Sn-Ag-Cu alloy system) on plate temperature under inert gas condition filling with Nitrogen. The surface tension of the lead free solder based on the Laplace theory is obtained numerically by using sessile drop profiles as boundary condition. The sessile drop profile is measured by the optical image method with CCD camera. Both effects of the plate temperature on the surface tension and the contact angle are clarified experimentally. The results contribute development of geometrical shape design of the solder joint on the electronic devices.

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A structural damping can be improved by installing high damping alloy in steel structures. This paper presents a fundamental study to increase the structural damping by adding high damping alloy in the steel structure. Free vibration tests and force vibration testes using test models composed of stainless steel plate and small Mn-Cu alloy plate, and vibration analyses for the test models are carried out to investigate damping ratios and natural frequencies of the complex plate. From the experimental and analytical results, effects of installation positions and installation area of the Mn-Cu alloy plate on the damping ratios and natural frequencies of stainless steel plate are made clear.

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Coalescence of Cu and Au clusters is studied by means of molecular-dynamics simulation. The interactions between Cu and Au atoms are calculated using the generic embedded-atom method potential. Cu and Au clusters before coalescence are assumed to have fcc and icosahedral structures. Their morphological change after coalescence is tracked, and the mechanism of formation of a core-shell cluster is especially focused on.

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Oscillations of double-walled carbon nanotubes are studied using molecular-dynamic simulation. Oscillatory frequencies of such carbon nanotube-based oscillators are found to be about 55.6GHz. How the logarithmic decrements of the oscillators depend on the diameters of carbon nanotubes is investigated.

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This paper examines compliance of a flexure tube used in torque-motors for servovalves. An electric input generates a torque on the armature mounted on the flexure tube. The deflection of the flexure tube due to the torque has been estimated by applying the beam theory for infinitesimal deflection. Since the theory assumes a large length/diameter ratio, its validity for small ratios that is usual in flexure tubes should be examined. The experiments and the FEM analysis carried out in this study proved that the beam theory for infinitesimal deflection is applicable without substantial error for flexure tubes of practical dimensions.

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The second-order statistics of the temperature and thermal stresses are analytically obtained in an annular disc with spatially random heat transfer coefficients (HTCs) on the upper and lower surfaces. This annular disc is assumed to have arbitrary variations in the HTCs solely in the radial direction and is subjected to deterministic axisymmetrical heating at the lateral surfaces. The stochastic temperature field is analysed by considering the annular disc to be multilayered with spatially constant, but random HTCs in each layer. The Vodicka's method and a perturbation method are employed to obtain the analytical solutions for the statistics. The autocorrelation coefficients of the random HTCs and cross-correlation coefficients between the HTCs on different surfaces are expressed in exponential function forms as a homogeneous random field. Numerical calculations are performed for annular discs similar to an annular fin, which comprise two types of distributions of the means of the HTCs. The effects of the magnitude of the means of HTCs, spatial variations in the means of HTCs and correlation strengths of the HTCs on the standard deviations of the temperature and thermal stresses are discussed.

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Welding is widely used for construction of many structures. Residual stress is generated because of locally given heat. Tensile residual stress on the surface degrades fatigue strength. In this paper, a method for reduction of residual stress using vibrations during welding is proposed Effectiveness of the proposed method is examined experimentally using heater instead of welding. Ultrasonic vibration is used during heating. It is found that residual stress near the bead is reduced when ultrasonic vibration is used.

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Welding is widely used for repair of many structures. Residual stress is generated because of locally given heat. Tensile residual stress on the surface degrades fatigue strength. In this paper, a method for reduction of residual stress using ultrasonic vibrations during welding is proposed Effectiveness of the proposed method is examined experimentally. Thick plate with groove is welded. It is found that tensile residual stress near the bead is reduced when ultrasonic vibration is used.

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Recently the compatibility of dash safety and lightweight is one of the most important technical subjects in body design. It is considered that the resistant strength has to reach a balanced level between the energy absorption structures and the deformation control structures for crash safety design. Although the CAE technology has been widely and successfully used to get the characteristic values in the crash safety evaluation,it is necessary to accurately estimate the energy absorption of the structural member of car in the initial stage of the design for time saving. This paper analytically refer to the energy absorption of the axial compression given at the collision.

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In the thin steel plates which are used in many industrial products, including automobiles, flaws on the plate surface and peeling during the surface treatment process are induced due to the use of many rollers in the conveyance process. These flaws lead to the deterioration of the quality of the plate surface. To solve this problem, the authors proposed a device for controlled levitation of rectangular sheet steel by means of a hybrid actuator using five electromagnets and thirty permanent magnets. For fundamental consideration we have reported concerning the optimal placement of permanent magnets using free - free beam with 2 permanent magnets. In this study, we attempt to determine the optimal placement and number of a thin rectangular steel plate that reduce the deflection.

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In this paper, it is evaluated global averages of elastic properties of composite material including spherical inclusions by the homogenization method. In the numerical method, it is assumed that particles of the same radius are arrayed in body-centered cubic, face-centered cubic, or simple cubic. It is obtain elastic properties by using the finite element method. In the analytical method, the properties are calculated by the mean field method or self-consistent method based on Eshelby's equivalent inclusion theory. As an example, it is considered that a material consists of epoxy and glass. The entire range of the volume fraction is evaluated by the three methods.

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The surface of a layered material was observed by electronic speckle pattern interferometry under the tensile test. Characteristics patterns as white points or lines were observed by electronic speckle pattern interferometry with crack generation. The crack generated on the surface was compared with the pattern. the position of the pattern corresponded with the position of the crack which was observed by microscope.

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The caustics method is a non-contact measurement method using a laser ray. This method has been applied to stress concentration state such as a crack tip to measure the stress intensity factors. This method has a lot of advantage: for example, it is applicable to a continuous measurement of a dynamic change of stress distribution; it is easy to set up the optical apparatus for measurements. For using the caustics method, the theoretical simulation is necessary to evaluate the stress intensity factors from the caustic images. So, in this paper, simulation program of caustic image based on the theory is developed. "Java" is used as the programming language, thus this program can be used through the following web site without limitation of time and area.

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To reduce tensile residual stress in a welded region, a new cooling method-which rapidly applies a water-shower behind the welding-torch-was developed. In this study, the water-shower cooling was applied to a surface of repair welded SUS304 plates. To verify the effectiveness of the water-shower cooling on the tensile residual stress reduction on the welded surfaces of the repair welded plates, residual stresses of the plates manufactured with or without water-shower cooling were experimentally determined. Experimental results show that tensile residual stress was generated on the welded surface when the water-shower cooling was not applied. The highest value of the tensile residual stress was more than 400MPa. The experimental results also show that the tensile residual stress was improved to compressive when the water-shower cooling was applied. The highest value of the compressive residual stress was more than 50MPa. It can be concluded that the water-shower cooling is effective for reducing tensile residual stress in the repair welded plates.

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In order to measure the contact pressure between gear teeth, we developed a thin-film pressure sensor with straight line type sensing part. The size of its part is 20μm in width and 3mm in length. The sensor consists of an insulation film 2.5μm, a sensing film 0.2μm, step fill film 0.2μm and a protection film 2μm. The sensor was sputtered onto gear tooth and showed low non-linearity and low hysteresis. As the result of pressure measurement using gear test device, approximately 900MPa was measured compared with a calculation result of 814MPa

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When we construct the transmission mechanism, ordinary we combine the cogwheel, cam and link etc., Therefore the one which has special form and functions will be able to be developed. Here we developed an unique transmission mechanism. A following disc (output shaft) and an active disc (input shaft) are opposed in the same side. And as the ball rolls between these disk. it proposes the function of the power transmit mechanism.

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Natural rubber has many industrial applications such as tires, the soles of shoes, breakes pads, etc. Friction is closely related to usage of rubber. In this study, a pin-on-disk type friction apparatus is used to measure the Tribology characteristics.

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It is important tightening the screw by fair tighten force. But, it is a difficult that we control the force of tighten screw. Moreover, it isn't researched it in recent years. We demonstrate about tighten characteristics of small screw by torque method. This paper describes that relationship between tightening torque and torque factor, torque factor and measurement number. We got a new useful knowledge about tighten characteristics of small screw.

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The present paper proposes a new optimization method of the sensor distribution. Structural health monitoring is a noticeable technology for the improvement of the reliability of the aged civil structures. Installation of the vast number of the sensors to the structure enables the automatic damage detection. This installation of the sensor requires much cost; it is indispensable to optimize the location and to minimize that number of installation. Therefore, in this paper, the optimization method of location of the sensors using mesh free method (MFM) is proposed. In this method, node of the MFM is considered as the sensors. A node is appropriately distributed by using EFGM. In the first half of this paper, to minimize the number of the sensors, consideration of the accuracy of the MFM using the small number of the nodes is conducted. In the second half, the crack length identification of the specimen using an inverse problem from the measurement of the sensor distributed by the method is analytically conducted. As the result, the crack length is successfully identified by the distributed sensors.

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Framed Structural Analysis was established by Slope -Deflection Method in the early 20th Century. With the progress of Electric Computer, it was completed by the Displacement Method. But, Force Method has more advantage in structural design. It is well known that the minimum potential energy theorem is proposed with respect to the displacements u_i of a given solid and theoretically it gives the upper bound of the stiffness evaluation while the minimum complementary energy theorem gives the lower bound so that the latter method may give the more conservative results of the stress and displacement calculations that the former. In this paper, a Framed Structural Analysis based on the mixed Method is reported.

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In this paper, first-order solutions for elastic problem with a slight-rough straight boundary shape as arbitrary shape function y=g(x) are obtained based on a perturbation theory. The first-order solutions obtained here are valid to O(ε) order where ε=A/λ<<1; A is the amplitude and λ is the characteristic wavelength in the shape function. Firstly, a general solution for elastic problem with straight boundary disturbed slightly by the shape function, y=g(x), is shown. In this study, cosine as typical periodic function is considered as the shape function.

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Recently, maintenance support systems with the Internet are used by several machine tool vendors. However, these maintenance support systems are depending upon each particular machine tool vendors. Moreover most methods of these maintenance systems are only monitoring of Open NC's console. Then, these maintenance systems can not handle other resources such as tools, materials and maintenance documents. Therefore, in this research proposed a portal collaboration type operation and maintenance support system which can handle not only controller's information but also other resources such as tools, materials and documents. This paper describes a concept of the portal collaboration type operation and maintenance support system, a management method for hand-written documents of the document management system and a prototype system based on the method.

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This paper presents a micro manipulation system with a force feedback ability. Operating such a system from a remote site typically suffers from transparency and time delay problem. Even a small time delay imposes difficulties on the operater, especially in force feedback. This problem is dealt with in this study by adopting a virtual model at the remote site. In order to generate a reasonable virtual model, we use actual SEM images from which a probe and an object to be handled are extracted and reconstructed as a virtual model through image processing.

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Power generation research using a variety of structure and machine vibrations is carried out in various institutions. Simultaneously, research with vibration suppression equipment is also being performed and there are numerous examples being put into practical use. This paper will describe a basic examination to determine the effectiveness of power generation and the attenuation effect when using a vibration power generator in a footbridge dynamic damper. Experiments were carried out with a power generation element to determine the basic characteristics of power generation and vibration using an electromagnetic induction-type power generation element. It was confirmed that voltage generation is almost proportional to velocity and the generated voltage has nearly no frequency dependency, while the effect of attenuation can be achieved by installing a resistor.

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Along with the steadily rising elderly population in Japan, the number of aged persons with difficulties in walking is increasing. This paper proposes a walking support machine for assisting the gait exercises of the patients in hospitals. This walking support machine has devices to unload patient's body weight and to prevent patient's falling. These devices consist of only mechanical components without actuators, controllers and batteries. The usefulness of the devices to prevent patient's falling is experimentally examined.

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Natural frequency of each motor component and electromagnetic field in axial gap type fan motor are investigated by modal analysis and measurement of magnetic flux density under operating condition. And, electromagnetic excitation force reproduced by using electromagnetic field analysis and structure analysis are used to predict vibration response under operating condition. In addition, noise and vibration reduction by structural modification in component of motor is proposed.

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In the factory, the continuous steel plates subjected to iron and steel processes are supported by a series of rollers during processes such as rolling. However, because roller comes in contact with the steel plates, the problem of surface quality deterioration arises. To solve this problem, we have developed a non-contact guide for parts of the steel plate at which its traveling direction changes in high-speed traveling by applying an electromagnetic force from the direction of the edge of the steel plate, and experimentally examine the effectiveness of the system. In this study, we confirm the influence on loop shape by high speed running.

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Reduction of seismic response of house is an important problem for aseismic design. In this paper, a cylindrical damper with silicon is developed for reduction of seismic response of two-story house. Resonance curves are obtained for various viscous coefficients of silicon. Peak responses in resonance curves are focused on. It is found that the peak responses are reduced when a spherical damper is used. Damping ratio, resonant frequency and peak response are obtained for various viscous coefficients of silicon.

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Reduction of seismic response of house is an important problem for aseismic design. In this paper, a spherical damper with silicon is developed for reduction of seismic response of two-story house. Resonance curves are obtained for various viscous coefficients of silicon. Peak responses in resonance curves are focused on. It is found that the peak responses are reduced when a spherical damper is used. Damping ratio, resonant frequency and peak response are obtained for various viscous coefficients of silicon.

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A dynamic damper using a Mn-Cu alloy spring is proposed to reduce vertical vibrations of long-span footbridges. Vibration response analyses of the footbridge with dynamic damper models considering the damping properties of the Mn-Cu alloy are carried out to investigate effects of the nonlinear damping properties of the Mn-Cu alloy on vibration control performances of the dynamic damper for the footbridge. In these analyses, the linear damping model and poly linear damping models are considered as analytical damping model of the Mn-Cu alloy spring. From the results, it is confirmed that the responses of the footbridge for the walking vibrations and the seismic waves can be reduced sufficiently by applying the dynamic damper using the Mn-Cu alloy spring.

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