The residual stress state inside the cruciform welded joints were measured using the pulsed neutron stress measurement method. The points of interest in this study are the weld toe and its interior. We also compared the cases with and without ultrasonic impact treatment (UIT), which is expected as a fatigue strength improvement technology. Furthermore, the case where tensile stress or compressive stress was applied after UIT treatment was also examined. The applied stresses at this time were 75 % or 85 % of the yield point, respectively. From the above, we considered the cause of the change in the residual stress on the surface after UIT treatment, which was clarified in the preliminary experiment, in the early stage of fatigue. As a result, the load after the UIT treatment caused plastic deformation in a part of the inside, which caused the redistribution of residual stress. It was also found that such changes in the internal residual stress state are the cause of the changes in the surface residual stress.

Electromagnetic flow meter (EMF) has been applied to measure a flow rate of sodium in circular pipe using permanent magnet for a loop-type sodium-cooled Fast Reactor (SFR), such as Monju. To extend EMF to a tank-type SFR only with an annular flow channel in primary coolant system, new annular-type EMF using electromagnet with M-shaped iron core and three coils has been developed in TOSHIBA. In annular-type EMF, sodium flows under non-uniform magnetic field in annular flow channel. Thus, it is important to understand detailed flow pattern with the interaction of such a magnetic field, for the practical application of annular-type EMF. Flow rate in a tank-type SFR is lower than that in a loop-type SFR and then the interaction parameter N is lower than 1. Here the flow and the magnetic fields in an annular flow channel is analyzed with using our modified 3D magneto-hydrodynamic (MHD) code, and comparison of the result with that of experiments using our sodium loop installing annular-type EMF is reported. As the results, it was confirmed that our simulation code had a good acuracy from the comparison of experimental results and the velocity profile in the boundary layer under magnetic field was not expressed by the simple wall function. In addition, the calibration method of the annular-type EMF using section model could be validated from simulation results.

In this paper, single water drop breakup in a high-speed gas flow behind shock wave, which is generated by shock tube, are repeatedly photographed under the same conditions. The laser rupture method, which have good shock wave generation timing, is adopted. The intensity values of the images are averaged to conduct statistical quantification of drop projection image thickness and volume. In early stage, drop projection image thickness and volume obtained from average intensity distribution are almost the same to drop projection image thickness and volume obtained from the original image. Additionally, we found that drop projection image volume increase rapidly at the time when the breakup initiates. Therefore, we propose a measurement method of breakup initiation time by utilizing the drop projection image volume. This breakup initiation time is compared with empirical equation of initiation time. Thus, it is shown that the proposed measurement method is valid.

This study investigates the mechanisms of the aerodynamic sound emitted by the collision of a vortex pair with a corner. When the vortex pair collides with the corner of a wall at a 45° angle of incidence, a reflection-symmetric vortex motion is observed, relatively strong vortices are generated on the wall, and the primary aerodynamic sound is generated. Subsequently, the vortex pair collides repetitively with the corner of the wall several times, which generates negligible aerodynamic sound. In contrast, when the angle of incidence is greater than 45°, non-reflection-symmetric vortex motion is observed. After the first collision of the vortex pair with the corner, complex vortex deformation and coalescence are observed. In this case, aerodynamic sound is generated by both the first wall collision and the complex vortex deformation and coalescence. This study also identifies that the vortex motion and aerodynamic sound generated by a vortex pair colliding with a wall corner depends on the angle of incidence. Although a precise comparison cannot be made, the maximum aerodynamic sound is observed when the angle of incidence is approximately 60°. The results of this study indicate that aerodynamic sound can be reduced by controlling the angle of incidence of the collision of the vortex pair with the corner.

Unsteady diffuser stall behavior in a centrifugal compressor with a vaneless diffuser was investigated by experimental and computational analyses. The diffuser stall generated as the mass flow rate decreased. The diffuser stall cell rotated at 25-30 % of the impeller rotational speed, with diffuser stall fluctuations observed at 180° from the cutoff. The diffuser stall fluctuation magnitude gradually increased near the cutoff. Based on diffuser inlet velocity measurements, the diffuser stall fluctuations generated near both the shroud and hub sides, and the diffuser stall appeared at 180° and 240° from the cutoff. According to the CFD analysis, the mass flow fluctuations at the diffuser exit showed a low mass flow region, rotating at approximately 25% of the impeller rotational speed. They began at 180° from the cutoff and developed as this region approached the cutoff. Therefore, the diffuser stall could be simulated by CFD analysis. First, the diffuser stall cell originated at 180° from the cutoff by interaction with boundary separation and impeller discharge vortex. Then, the diffuser stall cell further developed by boundary separation accumulation and the induced low velocity area, located at the stall cell center. The low velocity region formed a blockage across the diffuser passage span. The diffuser stall cell expanded in the impeller rotational direction due to boundary separation caused by a positive flow angle. Finally, the diffuser stall cell vanished when it passed the cutoff, because mass flow recovery occurred.

It is known that the longitudinal vortex alternately and periodically forms diagonally backward of the upstream cylinder of the cruciform system consisted of the upstream cylinder and the downstream strip-plate and causes the strong periodic lift force on the upstream cylinder. We have had a new concept to form a longitudinal vortex steadily at a fixed position, in where the gap between the upstream cylinder and the strip-plate, and it generates a steady lift force on the upstream cylinder. A new wind turbine, which has a circular cylinder blade and is driven by the longitudinal vortex, has been designed by this concept. In this study, the flow-visualization by the smoke-wind tunnel confirms the generation of the longitudinal vortex that was predicted by the numerical analysis. The cross-sectional size of the vortex depends on the diameter of the circular cylinder blade and increasing the number of blades does not affect its size strongly. The steady lift force acting on the circular cylinder blade was measured and the relationship with the relative attack angle which is determined by the mainstream flow velocity and the moving velocity of the cylinder blade in crossflow direction was examined. At a small gap between the circular cylinder and the strip-plate, the fluid force acts to reduce the move. When the normalized gap by the cylinder diameter is larger than 0.35, the fluid force causes to accelerate the cylinder faster in the small relative attack angle region. The performance characteristics of the cylinder blade wind turbine were evaluated and they show the similar characteristics to the drag type wind turbine.

The effects of the configurations and structural parameters of the cylinder blade wind turbine driven by the steady lift force of the longitudinal vortex on its rotation and drag force characteristics were investigated. When the longitudinal vortex was formed stably behind the moving direction of the cylinder blade, a negative pressure region was generated between the cylinder blade and the wake ring-plate. This negative pressure region applies the drag force on the cylinder blade in the mainstream direction simultaneously with the driving force in the rotation direction. The drag force was generated by the irregular formation of the necklace vortex when the cylinder blade was fixed, but the drag force increased even more when the necklace vortex became stable with the rotation. A complicated behavior of drag coefficients with increasing flow velocity was observed for the single-cylinder blade due to the influence of the inner region of a ring-plate and the tip-ends of the cylinder blade. In the case of the stepped cylinder blades, in which the unnecessary region where the influence of the necklace vortex does not occur was removed, the drag coefficient remained almost constant regardless of the flow velocity, and the formation of the necklace vortex was stabilized. In the multiple stepped cylinder blade wind turbine, the rotational speed increased by the effect of adjacent blades. The drag force acting on the entire wind turbine increased with the increasing of the blade number, but the drag force per blade was almost constant.

Effect of favorable pressure gradient on the wall similarity in turbulent boundary layer has been investigated experimentally. An appropriately adjusted pressure gradient produces an equilibrium boundary layer of which momentum thickness Reynolds number is constant. The wall shear stress was measured by three methods, which are direct measurement, Preston tube and Sublayer plate. A modified log-law considered the effects of the inertia and pressure gradient terms in the boundary layer equation gives better representation for the mean velocity profile subjected to favorable pressure gradient at finite Reynolds number. The velocity scale u_s applied to the modified log-law representation seems to be more relevant for turbulent intensity profile as well as mean velocity profile.

In this study, a large-eddy simulation (LES) is conducted to investigate meandering airflows generated throughout the underbody of a real-shaped train model in open air. In our previous study, this was shown by an LES of airflows around a simplified train model. The shape of the underbody affects the flow. However, thus far, no systematic analyses that consider bogies have been conducted. Our experimental results qualitatively reproduced the power spectra of lateral velocity fluctuations in the underbody obtained using a 1:8.4-scale train model on a moving belt in a wind tunnel. Results on the effects of various bogie shapes suggested that the meandering flow was primarily affected by the time-averaged profile of streamwise velocity. Thus, the effects of the bogie shape on airflow are considerable. Comparing bogie shapes with and without a side cover, that without a side cover generated meandering airflow with a slightly smaller peak frequency than that with a side cover, and a completely smooth bogie generated no meandering airflows. It was confirmed that this LES was useful as a technical tool to develop measures to reduce meandering airflows around high-speed trains.

It has been shown in our previous study that the bi-modal distribution is seen in the radial component of the gas velocity obtained in the turbulent flame brush, implying that the shear component of the Reynolds stress conditioned on the unburnt mixture and burnt gas can be measured if the coincident measurement of the three components of the gas velocity is conducted. Therefore, in this study, an attempt has been made to measure the shear component of the Reynolds stress within the turbulent flame brush of a turbulent premixed propane-air flame. Since the radial component of the gas velocity is bi-modal feature, the conditioned measurement of the gas velocity is indispensable. The unconditioned measurement overestimates the radial component of the average velocity and the RMS of the velocity fluctuation to unrealistic values, leading to fatal errors. It has been shown that the shear component of the Reynolds stress of non-reacting flow is much larger than those of the conditioned unburnt mixture and burnt gas. Due to the thermal expansion of gas across the flamelet, the gradient of the axial component of the gas velocity with respect to the radial direction decreases, the shear component of the Reynolds stress of the conditioned on the unburnt mixture and burnt gas decreases. Moreover, the correlation between the fluctuation of the radial and axial components of the gas velocity of the unburnt mixture and burnt gas decreases.

Liquid film thickness is an important parameter for predicting phase change heat transfer in pulsating heat pipes (PHPs). This study experimentally evaluated the liquid film thickness formed during the oscillation of the liquid column within PHPs. The liquid column was oscillated sinusoidally under various oscillating conditions to simulate the flow phenomena. The average thickness of the liquid film formed during the oscillations was determined by comparing the oscillation amplitudes of the tip of the liquid column with and without the liquid film. It was confirmed that the average thickness of the liquid film varied with the capillary number for each working liquid (water, ethanol, and FC-40). The characteristic velocity of the capillary number was the time-average velocity of the tip of the liquid column, which was derived by assuming that the tip of the liquid column oscillated sinusoidally. Additionally, the average liquid film thicknesses during the liquid column oscillations were evaluated according to the correlations for various flow conditions proposed in previous studies. In this evaluation, the velocity and acceleration values obtained by assuming that the tip of the liquid column oscillated sinusoidally were determined based on the experimental results. This evaluation demonstrated the acceleration effect, thereby indicating that the acceleration made the liquid film thinner when the capillary number was higher than the threshold of the capillary number for each working liquid. Finally, empirical correlations with and without the acceleration effect were proposed for the average liquid film thickness of oscillating flows in terms of capillary and Laplace numbers. It was demonstrated that the proposed correlations could predict the average liquid film thickness within the range of approximately ±15 % accuracy.

Recently, welfare vehicles are widely used among the aged. However, it is hard for inexperienced beginners or the aged to manipulate the welfare vehicle in narrow and crowded places. For the problem, automatic driving of welfare vehicles has been studied. The welfare vehicle drives on the mixed traffic area with humans. As the traffic area is so complicated for the automatic drive, the control method should be changed between manual driving and automatic driving according to the driving situation. In this paper, an automatic driving system with obstacle avoidance using Mixed Reality (MR) is proposed. The characteristic of the system is to use a virtual platoon control, i.e. the virtual vehicle drives avoiding obstacles on the head mounted display (HMD), and the welfare vehicle follows the virtual vehicle. The HMD detects the obstacles using the spatial mapping, and the avoiding path is planned using A* function of Unity. The effectiveness of proposed system is evaluated in some driving scenes.

Recently, dump trucks working in mines are becoming unmanned in order to reduce labor costs and the risk of human injury. If we use multiple fleets of dump trucks, their coordination is necessary to avoid traffic jams. In this paper, we propose a new algorithm of controlling dump truck fleets so that mining productivity can be improved. First, we introduce an index, time margin, which is determined as a gap between the expected time to arrive at a loading area and the ideal arrival time at the loading area for zero idle time of the loading machine. Secondly, we propose an algorithm that optimizes the order in which dump trucks pass through intersections using the time margin. The algorithm calculates how much time the dump trucks lose by slowing down at intersections, and estimates how long it is delayed in arrival at the loading area using the time margin. The algorithm then determines the optimized order of the dump trucks that has the minimum total time of their arrival delay. Simulations show that the proposed method reduces delay in arrival at loading areas and improves the amount of production of the overall mine, due to appropriate prioritization of dump truck fleets.

This paper discusses a spillover phenomenon on the lower frequency side in the multimode piezoelectric NC (Negative Capacitor)-shunt damping problem. In contrast to standard spillover phenomena, this phenomenon is quite interesting because the instability is caused by neglecting lower frequency vibration modes in controller design. First, an example of spillover phenomenon on the lower frequency side is illustrated. When the NC-shunt damping problem is interpreted as the H_∞-control problem, the combination of mechanical and electrical systems is recognized as a stable generalized plant and the admittance of the NC circuit is recognized as an unstable controller. The circuit parameters of NC-circuits are tuned for each vibration mode, and then, it is demonstrated that the closed loop system becomes unstable when the first vibration mode is neglected in parameter tuning. Then, the graphical instability analyses are carried out by investigating the Bode and Nyquist diagrams. According to the Nyquist stability criterion, the closed loop system between the stable generalized plant and the unstable controller becomes stable if and only if the Nyquist diagram encircles −1+ j0 once in the counter-clockwise direction on the complex plane. In the example of unstable closed loop system, it is confirmed that the Nyquist diagram encircles −1+ j0 once in the clockwise direction and that both gain and phase intersections occur at the anti-resonance frequency in the Bode diagram. Finally, the approximate instability analysis is carried out to prove that the instability is caused by simultaneous gain and phase intersections at the anti-resonance frequency indeed. From the instability analysis, it is clarified that spillover phenomenon on the lower frequency side is not a special phenomenon limited to a specific experimental setup but can generally occur in the piezoelectric NC-shunt damping problem.

A swarm system is a branch of a collection of robotic systems composed of a lot of “simple” robots. In general, group cooperative behaviors require a considerable amount of information, numerous sensors and complicated networks, which makes the designing of their control system much difficult; therefore, a more natural and sensorless-based interaction is expected to aid the building of an easy-to-understand control scheme for elaborate swarm systems. This paper inspired by the collective motions of army ants focuses on a group behavior in which individuals can cooperate with each other using its own body. Army ants cooperate with one another to overcome large gaps, such as the gap between the tree and its leaf, wherein some ants form a pillar by connecting with one another, such that other ants can walk on it to cross the gap. This paper presents a sensorless swarm system in which the mechanical structure and the physical interaction of the system is only utilized. The collaborative obstacle-crossing task is considered, and the robotic swarm system, comprising the individual robot along with the mechanical interaction mechanism, is constructed. Through an obstacle climbing experiment and the passing of a gap, the validity of the mechanical interaction approach is examined.

Although bladed disks are nominally designed to be cyclically symmetric (tuned system), the vibration characteristics of all the blades on a disk are slightly different due to the manufacturing tolerance, deviations in the material properties, and wear during operation. These small variations break the cyclic symmetry and split the eigenvalue pairs. Bladed disks with small variations are referred to as a mistuned system. In the forced response of a mistuned bladed disk, the responses of all the blades become different, and the response of a certain blade may become extremely large due to splitting of the duplicated eigenvalues and distortion of the vibration modes. On the other hand, many researchers suggest that mistuning suppresses blade flutter, because the complete traveling wave mode is not formed in a disk. In the previous paper, authors studied the forced response of the mistuned bladed disk, using the reduced order model SNM (Subset of Nominal system Modes), and clarified that the effect of the bladed disk structure on the amplification factor. This work is a follow-up study on the previous paper. The stability analyses of mistuned bladed disks with the free-standing blade structure and the continuous ring-blade structure are carried out extensively, using the reduced order model SNM. Comparing the results of the stability analyses of mistuned bladed disks, the effect of the bladed disk structure on the blade flutter is clarified.

In this paper, we report the effect of the installation angle of a separated dual chamber single rod type damper using elastomer particles on the damping force characteristics. The particle assemblage damper uses soft / hard particles and suppresses vibrations by the compression reaction force of particles and the friction force between particles or between particle walls. This is attracting attention as a solution to the problem of oil leakage of oil damper. As a result of calculation using the discrete element method (DEM), in the case of only one chamber is filled with particles, when it was found that the mounting angle of the damper is made closer to the vertical from the horizontal, the particles gather at the bottom of the damper due to gravity and the movement of the particles is restricted, so that the damping force increases. In addition, when both chambers are filled with particles, the damping force that becomes larger by compressing particles to the bottom side of the damper, however, it is that by the restoring force of the particles already compressed in the other room is cancelled, so it was found that there was no significant change in damping force even if the installation angle was changed.

This paper addresses the modular concept concurrent design of NVH (Noise, Vibration and Harshness) performance. Recent development of modularization design in car companies requires the realization of the modularization of NVH design process. However, there are difficulties for the modularization design of the strong coupling vibration among each module. Modularization design requires the realization of concurrent design by two or more groups. In this case, a true concurrent design cannot be realized unless the problem that a slight structural modification seriously changes the characteristics of a whole structure due to the strong coupling is solved. In this paper, a concurrent modularization design method of NVH performance which utilizes the kCA (kernel Compliance Analysis) was proposed to overcome the strong coupling problem. The basic concept of the kCA is adopted for both the placement of resonance frequencies and the reduction of resonance responses of a whole structure, by the comprehension of resonance generation mechanism between coupled two subsystems. Therefore, the kCA was adopted in this paper as a basis of the proposed method to overcome the strong coupling problem. In the paper, it is shown that the proposed method provides the advantage of no rework at every stage of the design, from upstream to downstream, if two groups which design two subsystems separately follow the specifications which is decided by the proposed design method. Finally, the method was verified by a numerical case study.

For vehicle-type construction machinery, it has been obligated to reduce vibration of cab, in which operator is being exposed continuously to severe vibration, for manufacturer on the view point of occupational safety and health. Usually operator controls any kinds of earthwork at construction site in cab, which is isolated from sources of sound and vibration by vibration absorber. As this absorber, i.e. cab mount, rubber mount of natural rubber (NR) had been replaced to viscous mount, in which silicon oil is enclosed inside, from the later of 1990s, then viscous mount has contributed to reduce vibration and extend endurance life of cab much more than rubber mount up to now. This system involves several major eigenvalues below 10Hz, so viscous mount has been developed to add much damping to them, but it has very complicated frequency characteristics for dynamic stiffness though rubber mount could be expressed simply by constant dynamic spring and loss factor. But in spite of this kind of difficulties to represent dynamic stiffness of viscous mount, it has been proposed to analyze cab vibration with suitable mechanical model of viscous mount. Furthermore though the establishment of vibration analysis for cab has been required to shorten development time and reduce its expenses for ensuring design confidence at product design, it could be considered that the vibration analysis of cab system with viscous mount could not be applied enough to concept design.

In this study, so as to establish analysis methodology of cab vibration with viscous mount, a mechanical model of four elements, i.e. two springs and dampers, is proposed and the results of verification to compare analysis with measurement for cab vibration are shown.

It is desired that the forced self-excited vibrations of structures subjected to the vortex excitation and the long-period earthquake are quenched. Therefore, this paper deals with the vibration control of self-excited system and forced self-excited system using dynamic vibration absorber. Vibration quenching is researched using characteristic roots of the system and the entrained periodic solutions obtained by the shooting method. As a result of numerical calculation using the fact that the optimum vibration control of the self-excited vibration system can be performed by the theory that omits the nonlinear term of the damping term and considers only the linear term, following was made clear: At first increase the mass ratio of the dynamic vibration absorber with the increase of the negative damping coefficient. And adopt the several percent larger natural angular frequency ratio than the optimum vibration control value of forced vibration, and adopt the several tens of percent larger damping ratio than the optimum value of forced vibration, depending on the value of the negative damping coefficient. About the vibration quenching of forced self-excited vibration, following was made clear: (1) When the non-linear damping term, which is the cause of self-excited vibration, is small and the amplitude of force is also small, optimal control is approximately performed using the optimal values of the parameters for vibration quenching of forced vibration without damping. (2) When the amplitude of the forced force is large, the vibration quenching effect is reduced if the above mentioned approximate optimal values are used. The vibration quenching effect can be improved by using the smaller angular frequency ratio. (3) As the non-linear damping term increases, the optimal angular frequency ratio and optimal damping ratio of the dynamic absorber decrease.

This study conducts the modeling and numerical analysis of a screw dislocation in a three-dimensional continuous medium. Our modeling is based on the differential geometry of Weitzenböck manifold, i.e., a Riemann-Cartan manifold which equips itself with non-zero torsion in the affine connection. Following to the standard framework of geometrical elasto-plasticity, we introduce the three smooth manifolds representing the reference R, intermediate B and current S configurations and express the kinematics using the diffeomorphisms between them. Our primary concern is the geometrical construction of the intermediate configuration B. For a given dislocation density τ, we calculated the plastic distorsion F_p through the integration of τ by homotopy operator. This analysis yields the dual frame ϑ of the Cartan moving frame, which satisfies the first structure equation and Bianchi identity, simultaneously. The current configuration S is obtained by embedding of B to the conventional Euclidean space R³ so as to minimize the strain energy functional. The variational problem is solved numerically using the isogeometric analysis; Galerkin method with non-uniform rational B-spline basis functions. Present analysis revealed that far-field stresses around a screw dislocation agree quantitatively well with those of the Volterra dislocation. A notable difference is non-singularity at the dislocation core. Another remarkable feature is the emergence of hydrostatic pressure due to the geometrical nonlinearity. We also found that surface displacements include a vortex centered at the dislocation line. This is a realization of Eshelby twist.

In recent years, the demands for mirror finishing by cutting have increased, because the surface quality requirement in die and mold has become severer. In order to realize mirror surface finish by cutting, it is necessary to reduce the influence of tool non-repeatable run-out (NRRO) on machining surface. Rolling bearings used in a spindle for machine tools may cause NRRO of cutting tool due to rolling element revolution. In order to reduce the influence of NRRO on machining surface, an excitation system which can generate counter excitation force has been proposed in this study. The gradual change of multiple peaks of NRRO in frequency domain was observed. Excitation experiment results confirmed that the proposed excitation system can reduce NRRO from the relative displacement between the table and the tool. Furthermore, actual cutting results confirmed a correlation between NRRO reduction of the relative displacement and NRRO reduction on the machined surface.

Cold forging is a typical manufacturing technology to produce various mechanical components with high productivity. Various process parameters such as punch velocity and forging loads are adjusted for successful forging. In this paper, a backward extrusion of aluminum alloy using the spring devices is considered. The target product handled in this paper has earing, around which the risk of crack is high with inappropriate process parameters. Therefore, it is important to determine optimal process parameters to minimize the risk of crack. In addition, in the cold forging, it is important to form the product with minimum forging load. In this paper, a multi-objective process parameters optimization minimizing the risk of crack and the forging energy is performed using numerical simulation. Numerical simulation in the forging is so intensive that sequential approximate optimization using radial basis function is adopted to determine the optimal process parameters with a small number of simulations. Through the numerical result, the pareto-frontier between the risk of crack and the forging energy is clarified. In addition, it is found that the smooth flow lines along the product shape can be obtained. Based on the numerical result, the experiment is also carried out to validate the proposed approach.

The purpose of this study is to carry out the basic verification necessary for the correct evaluation of the residual stress of shot peened spring steel by the cosα method. Spring steel (JIS-SUP9) was used as the specimen. Shot peening (SP) was performed on the surface of the specimen by changing the direction and the number of SP. In the X-ray stress measurement, the Debye ring was measured from five directions for each measurement point and used to determine the residual stress. We also examined the effects of changing X-ray incident angles. Residual stress was determined assuming plane stress or tri-axial stress, respectively. As a result, it was found that out-of-plane shear stress (τ_xz) may occur depending on the direction of SP, and in that case, if stress analysis assuming plane stress is performed, a measurement error will occur. Furthermore, it was found that the smaller the incident angle of X-rays, the larger the measurement error.

In the field of sports engineering, though policies for developing human resources in sports are promoted nationally, lack of managers and coaches who can give highly-qualified instruction to an individual player is an urgent problem. Therefore, a swing measurement unit is developed for quantitatively analyzing a batter’s swing form in baseball. However, it is difficult for managers and coaches to utilize the sensor data and give players an instruction based on the data. The purpose of the study is to find out new knowledge for giving appropriate advice to individual players by analyzing the swing characteristics with the swing measurement unit. In order to verify whether the swing characteristics of university baseball players can be properly classified, the swing data and batting performance data were classified individually using the k-means method. As a result, when the swing characteristics and batting performance were classified into two cluster by the k-means method, the players could be classified with high accuracy. Furthermore, the principal component analysis was performed to examine the relationship between the measurement results obtained from the swing measurement device and the swing characteristics in conjunction with this classification result. The results of principal component analysis also showed that it was possible to classify high-ranked players and low-ranked players. From these results, it showed elements of the measurement items related to classification. It was found that players with long swing rotational radius, short swing time and high head speed were classified as high-ranked players.

Palpation is an important medical skill to find bad lumps or tumors in the first medical examination. However, the practical palpation training has not been conducted enough to avoid patient’s risk in medical educational institutions. Hence, a virtual reality training system is useful for reproducing various affected parts. In this paper, the particle method to calculate the deformation of biomaterial with non-uniform elasticity is developed for the VR palpation system, which is based on the moving particle semi-implicit method (MPS). The target biological model is a maxillofacial part for dental palpation, which is discretized with 2 mm in particle intervals. In the analysis, we set a local calculation region near the palpation position to reduce computational time. The local region has a spherical lump of 10 mm in diameter. The accuracy of the present calculation is examined through comparing FEM’s one about deformation and stress. Here, we mention that there is hardly a comparison of MPS’s and FEM’s stress for biological tissues. This is because that the definition of pressure in MPS is different from one in FEM. Evaluating the method of stress on the basis of von Mises stress is newly proposed in order to improve the problem. Consequently, the displacement and stress by the present particle method and FEM are qualitatively the same distributions for an example local model with a lump. Furthermore, large elastic deformation is calculated with large palpation pressure. It is clarified that the palpation pressure is about 500 Pa to deform 5mm on the palpation surface. Finally, the particle method can simulate the deformation and stress of the practical maxillofacial model with a lump by the palpation pressures of 400 Pa and 600 Pa. In addition, computer graphics are made to easily understand the maxillofacial surface deformation for a VR system.

This paper proposes a signal processing method to extract the longitudinal creep force from the strain signal that is acquired by an instrumented wheelset in a railway vehicle. The longitudinal creep force is an important physical quantity to discuss the wheel/rail contact condition and the curving performance. Although the instrumented wheelset can detect the longitudinal creep force by the use of the strain signals to measure the wheel load, a wheel rotation sensor such as a rotary encoder is needed to extract the quantitative force data in the conventional signal processing method. This paper proposes a novel signal processing method using the least square technique, which can extract the average value of the longitudinal creep force in a wheel rotation. The numerical tests using dummy signals show that the proposed method has similar frequency characteristics to the ordinary moving average filter in the region of frequency under 10 Hz when the wheel rotation speed is 20 rad/sec. It is also shown that the proposed method can extract the longitudinal creep force from the actual strain data acquired in the running test of real railway vehicle.

The purpose of this paper is to clarify the effects of operation of braking devices by sliding friction against rails (rail brake) on the dynamic characteristics of gantry cranes for container handling after runaway caused by unexpected wind gust by a numerical analysis and to obtain the scientific knowledge which serves to develop the technology for safe stopping. Dynamic characteristics of the crane were calculated by the dynamic numerical simulation analysis using FEM. The crane was modeled by three-dimensional beam elements. The interaction forces that define the resistance characteristics of the crane runaway generated at the contact part between wheels of the traveling system and the rails were modeled. And the interaction forces at the contact part between the rail brakes and the rails were also modeled. For the wind gust that becomes runaway driving source, the wind direction, the velocity distribution in the vertical direction and the time change of the wind velocity were modeled. The load that the crane receives by the wind was calculated based on the ISO standard of the wind load assessment of cranes. In the analysis conditions of this paper, the runaway of the whole crane started when the driving wheels of the land side became slide state after those of the sea side became slide state. The dynamic characteristics through the stop of the crane after the operation of the rail brakes concerning cases of varying rail brake operation characteristics were analyzed and considered. The operating characteristics were defined by the time increase rate of the pressing load of the brake shoe, dP_B/dt, the maximum value of it, P_Bmax, and the timing that the operation starts. The crane reached the stop after the runaway velocity decreased with the swing of the rail longitudinal direction of the crane structural system which consists mainly of the legs, the boom and the girder. When the acceleration of the upper part of the crane structural system increases by the rail brake operation, the generated inertial force reached the level that should be considered in checking of the structural safety. Finally, the relationship between the braking distance as an evaluation index of braking performance of the rail brake and the braking operation characteristics was presented and discussed.

Effects of the rotational component on a prediction result of the shock response spectrum given by a transfer function synthesis method are discussed. Shock environment on two structure models, which are a plate model connected by two flat plates and a shock tester model installing a test specimen, is analyzed. The transfer functions of the substructures in these models are initially computed and are synthesized to predict the shock response spectrum in the coupled structure. In the synthesis analysis without the rotational component, the prediction accuracy of the shock response spectrum in the plate model significantly decreases, whereas that in the shock tester model is unaffected. This is attributed to the fact that the shock tester model has high flexible rigidity originated from its structural configuration. This result indicates that the shock response spectrum on the shock tester model can be predicted with sufficient accuracy by only synthesizing the transfer functions with the translation component.

This research aims at developing a technology strategy coordinating with international regulations taking their recent globalization into account. Since recognizing the trend of establishment of the international regulation is indispensable as the assumption for building the strategy, this paper categorizes established and amended international regulations focusing on the safety requirements in the International Maritime Organization (IMO). The research firstly reviews the scheme and procedure for developing the new requirements. Then, based on IMO-MSC documents on new work program proposed by member States for 14 years, three categories, a motive for the development of safety requirements, required safety area, and regulatory issues, are investigated as significant factors. The result shows the identification of taxonomic classification in each category. This paper also shows the points to be considered, diversity of a motive and potential background that cannot be found in the IMO documents such as domestic political situation. Since the categorization in this paper can be generalized easily, application to other areas, such as international aviation and automobile sectors, are recommended.