With recent developments in the technology of intelligent materials, including shape memory alloys that deform autonomously depending on changes in the environment, such as temperature, it is expected that next-generation actuators that are simple, lightweight, and compact will also be developed. Consequently, in this paper, we investigated the disc spring type actuator made of Ti-Ni shape memory alloy (SMA), which is more compact than the conventional SMA coil spring type actuator. Firstly, prototype SMA disc springs were made from a thin SMA plate by metal stamping and shape-memory treatment. Secondly, we measured load-displacement curve of this prototype at both high and low temperatures. Thirdly, from the experimental results, the difference between displacements at low and high temperatures was used to estimate the performance (output displacement) of the SMA disc spring. The observations revealed that output displacement rate of the SMA disc spring was greater than 50% when the load was 30N. Compared to the coil spring, a similar effect would be obtained in approximately 37% of the space by the SMA disc spring. Finally, we conducted a finite element analysis of the SMA disc spring using a non-linear finite element analysis program, LS-DYNA. The validity of the analysis procedure was confirmed by comparing the analysis results with the experimental results.

Japan has a special feature that there are a lot of natural disasters compared with other country. The volcanic explosion which has occurred at the Ontake-mountain in 2012 was enormous. Recently, the volcanic explosion at Mt. Fuji has been paid attention. If Mt. Fuji is exploded, it is expected that automotive engine inhales aerosol-like volcanic ash and its ash deposits on the inner surface of cylinder, and also the breaking performance could be decreased by the volcanic ash deposited on the surface of the break disk, which will bring about a traffic confusion in the whole Kanto area. As other serious problem, the site of all land-based gas turbines utilized as power generator is mainly concentrated in Tokyo bay. If the volcanic ash falls down and is inhaled in the air intake, all generators would be stopped and a blackout would be occurred finally. It is needed that such trouble related with the volcanic explosion is prevented in advance. In this study, the volcanic ash deposit simulator, which can impact and deposit aerosol-like volcanic ash under a high-temperature and high-speed gas flow, is developed in order to identify volcanic ash deposition criterion. Here, the deposition behavior on Type 304 stainless steel plate-shaped sample is examined by changing gas pressure, gas temperature and substrate temperature condition. The ash-deposited plate is also exposed at a high-temperature in order to clarify how volcanic ash attacks the structural part.

Elastic moduli of metal sheets have planar anisotropy determined by crystalline texture. Texture control is effective in raising Young's modulus of steel sheets in some directions on the plane. Some steel sheets with strong elastic anisotropy produced by cold-rolling and continuous annealing can be applied to some structural components to improve their rigidity. However, the elastic anisotropy of the steel sheet with texture has been applied to few industrial products because the structural design using anisotropic materials is difficult. In the present study, two steel sheets with different texture were prepared for the experiments and numerical simulation, the torsional rigidity was investigated in steel square tubes with elastic anisotropy. Torsional rigidity have been examined, it depended on the direction of the sheet applied to the component. It was most effectively improved when the direction of the highest shear modulus coincided with longitudinal direction in the square tube. Elastic compliance matrix was identified by fitting to Young's modulus of steel sheet with elastic anisotropy, and finite element analysis was carried out using shell elements by considering the elastic anisotropy. Furthermore, the Voigt-Reuss assumption calculations of elastic anisotropy based on the texture measurements revealed that the decreases in shear modulus at diagonal direction were caused by the ODF intensity around {110}<001> component, and the increases in shear modulus were caused by {112}<110> component.

This paper discuss about suitable damage size that should be detected by ultrasonic testing (UT) for nuclear power plant piping when consider about propagation of IGSCC. The power plant piping loop is inspected using UT as an in-service inspection (ISI). The reliability of UT result is affected by examination personnel. In this paper, the reliability of UT is defined simplified POD (Probability of detection) curve. The curve is defined by only three parameters, minimum detectable crack depth (a₀), most detectable crack depth (a₁) and maximum POD(m). The reliability of plant piping with different diameters are estimated by using this POD curve. The Failure probabilities were calculated with Monte Carlo approach. In case of low carbon stainless steel with IGSCC, a₁ and m are less than 6 mm and 0.96 respectively, the piping loop failure probability is under 1x10^-7. In another case of sensitized stainless steel with IGSCC, a₁ and m are less than 6 mm and 0.96, the piping loop failure probability is under 1x10^-3. It was found that the parameters of a₁ and m do not affect plant reliability when a₁ is between 3 to 6mm, and m is between 1.00 to 0.96. This result can be used to decide the requirement for examination personnel reliability.

In recent advanced semiconductor products, elements of thickness and width are frequently in nanoscale. As the size of elements reduces to nanometer, a ratio of surface to volume increases. Surface properties, such as surface stresses and surface elasticity, influence on the distributions of bulk stresses near the surface. In the present study, the singular stress at the corner in an anisotropic two-dimensional multi-wedge joint consisting of three kinds of material is analyzed using molecular statics (MS) method and the anisotropic elasticity theory with a boundary condition considering interface properties. The joints are composed of Ni, Au and Cu. Several joints with different wedge angles at the interface are analyzed. Distributions of atomic stress calculated by the MS method are compared with those by the theory. In the results of the MS analysis, stress jumps exist at the interface in the circumferential direction of the stress distribution around the stress singular point. It is supposed that these are attributed to the influence of interface stresses. Then, interface stresses and elastic properties at the interfaces are investigated using the MS method. The obtained interface properties are used in the stress analysis using the Stroh’s formalism. Finally, the theoretical analysis considering the interface properties can be expressed the jumps of stress at the interfaces.

Crack opening displacement around a mode I surface crack tip was measured by digital image correlation method to determine the stress intensity factor and the effective stress intensity factor range. First, the mode I surface crack was introduced into a specimen of A7075 aluminum alloy by a servo-hydraulic fatigue testing machine. Then, the specimen was annealed to remove a compressive residual stress around the crack and used to demonstrate the measurement of the stress intensity factor on the basis of crack opening displacement measured by digital image correlation method. Second, the effective stress intensity factor range was determined from the crack opening displacement during the pulsating tension test under three kinds of stress ratios and used to arrange the crack propagation rate. The difference between the measured stress intensity factors of the annealed specimen and the factors proposed by the numerical solution was less than 10%. Additionally, the crack opening displacement of the propagation process under pulsating tension was subjected to the influence of residual stress and became smaller than the crack opening displacements calculated by the theoretical solution. The crack opening stress calculated from the crack opening displacement was larger than the minimum stress in the case of R=0 and R=0.2. On the other hand, the crack opening stress was clearly smaller than the minimum stress in R=0.5. It was clear that the relationship between the crack propagation rate and the effective stress intensity factor range that determined by the crack opening displacement was barely dependent on the stress ratio.

We proposed a new technique to analyze the asymptotic solution around a three dimensional interface corners. We analyzed the scalar parameters of the asymptotic solutions using the H-integral, which is a conservative integral, in conjunction with the finite element analysis. Singular orders of these three-dimensional corners were obtained using the finite element method for the eigen analysis. If λ is an eigen value of a three dimensional corner, -λ-1 is also an eigen value. Complementary eigen values and eigen vectors are used for the H-integral analysis to obtain the scalar parameters. If we select the eigenvalue, -λ-1, as the complementary eigenvalue for the H-integral, the H-integral corresponds with a scalar parameter of the asymptotic solution. We proposed the normalization of the eigenvalues for defining the obtained scalar parameters as the unique values. We demonstrate that the obtained asymptotic solutions correspond well with the stress field obtained by the finite element analyses around three-dimensional interface corners.

Probabilistic fracture mechanics (PFM) analysis is an evaluation method for the structural integrity of components containing a crack, with considering the random variability of the input physical parameters, such as crack growth rate. The characteristics of the variability are described in the form of probability distribution, which is defined by probabilistic parameters such as mean and variance. Without sufficient information about the random variability, the parameter of the probability distribution may contain uncertainty, so that evaluated failure probability also contains uncertainty. Therefore, as the output of PFM analyses, not only the failure probability but also their uncertainty derived from the parameter uncertainty should be evaluated. In this paper, we describe the parameter uncertainty in the form of the interval of the parameter. We propose the simple estimation method for upper and lower bound of the interval of the PFM result derived from the above parameter interval. Additionally, we propose the uncertainty index that denotes the interval of the result derived from the interval of each parameter. These proposals are based on the first order reliability method (FORM). The proposed estimation method and the uncertainty index are validated through the evaluations, whose conditions are based on past evaluation study. At the first stage, accuracy of the evaluated result by FORM is validated through comparison between FORM and the directional simulation method. And then, the proposed methods are validated through the comparison with the result by FORM.

Some of the causes of quenching cracks are considered to be related to ununiform cooling and variation of the material composition. Segregation is always generated in the inner parts of large steel ingots during production process. Especially in the forging process of large products, it is considered that the variation of the material composition affects the quenching crack generation. It is important to clarify the effect of extent of the segregation in the large forged products on quenching crack generation. Quenching test using cylindrical test specimens, which were cut out from the segregated part and the less-segregated part in large forged materials of a 40 ton ingot, was conducted. As a result, it is found that test materials from the segregated parts showed low resistance against quenching crack that means high possibility of quenching crack generation than those of the less-segregated parts. In addition, quenching test using large forged products which have no-segregation and segregation in the surface were conducted. In case of no-segregation in the surface, quenching cracks did not initiate in the surface where high quenching stress was estimated to occur by the quenching analysis. In case of segregation in the surface, however, quenching crack initiated in the surface. Those results reveal that segregation affects the initiation of quenching crack. It should be noted that the existence of segregation in the material surface has the substantial influence on quenching crack generation.

The existing collision energy absorber of vehicle collapse ideally only 70% deformation and the high initial peak load is a problem. So our group has paid attention to the reversed spiral cylindrical origami structure (RSC) to overcome these two problems, but the energy absorption amount of RSC was low. However, after optimization analysis, the energy absorption amount of optimal RSC has been obtained about 1.4 times of the existing collision energy absorber. But, because the production of RSC is expensive, the industrialization of it is difficult to realize. Here, recently two pairing origami structures are gaining attention: Nojima polyhedron (NP) and Tachi-Miura polyhedron (TMP) are compared from the point of crash absorbing energy characteristics. In this paper, we focus on the investigation of the absorbing energy performance and consider the application of these pairing origami structures to expect to be used as the collision energy absorber of vehicles of steel material. And both are compared with RSC which is manufactured by hydro forming and the conventional rectangular cross section structure.

It is known that fluid-borne noise emitted from a hydraulic system often causes severe discomfort of the operator. It is also known that the noise can change as the system warms up. The temporal change in steady operation can be a factor for misperception of mechanical failure, because noise can play an important role as a signal that indicates abnormal operation. It is therefore important to understand the behavior of hydraulic pressure ripples that are a source of hydraulic noise in steady operation, and how they change in relation to the operating time. This study has investigated the influence of oil temperature changing over time on pressure ripples in a hydraulic line in steady operation. Variables that can change in steady operation have been considered using mathematical models of the pressure ripples. The consideration has shown that, when there is no air-entrainment from an outer system, the change over time is caused solely by the change of the hydraulic oil temperature. Physical properties of the oil and speed of sound in the oil have been defined as temperature-related variables in the mathematical models. The physical properties that are used in the mathematical models have been obtained directly from the manufacturer. In contrast, the speed of sound in the oil has to be obtained using theoretical approaches. The behaviors of the hydraulic pressure ripples in three simple hydraulic systems have been investigated using mathematical models that took into account the thermal properties. Each hydraulic system consists of a hydraulic pump, a straight pipe and a termination condition that is one of the following typical three types: non-reflection, valve and volume. The mathematical models have shown distinct behaviors resulting from the change in the oil temperature. The behaviors have been verified experimentally.

The torque converter is a kind of fluid coupling that is widely used as a start-up device for automobiles equipped with an automatic transmission. A lock-up clutch is often incorporated in the torque converter in order to improve vehicle fuel economy in the higher speed ratio range. This improvement is obtained because the lock-up clutch can reduce fluid losses by engaging the input and output shafts to rotate at relative speeds with only a small amount of slip. Operation of the lock-up clutch is controlled mainly by supply and discharge oil pressure of the torque converter. The purpose of this study was to better understand clutch behavior under the influence of oil flow. Flow through the lock-up clutch was computed by using a commercial CFD code at three speed ratios of 0.8, 1.0 and 1.2 under the prescribed supply and discharge oil pressure sequence. Unsteady computations were conducted under the assumption that the flow was weakly coupled with the solid mass motion. Quasi-steady computations were also conducted under the assumption that a dynamically equilibrium state was maintained when the clutch moved. The results showed that the response time of the lock-up clutch increased with a higher speed ratio and that flow through the clutch changed directions from outward to inward in the engagement process in all cases. The computed response time coincided reasonably well with the experimental data obtained with the actual machine. It was also found that the quasi-steady analysis results showed an unreasonable or meaningless tendency regarding the response time.

In this study, in order to clarify a relation between thermodynamic effect, which suppresses cavitation, and scale effect, which promotes cavitation, tunnel experiment was done with NACA16012 single hydrofoil in hot water. Appearance of the effects was estimated by occurrence region of cavitation for angle of attack vs cavitation number and variation of cavitation patterns. Main flow temperature was 30°C and 70°C. By increasing main flow temperature under constant Reynolds number condition, scale effect was took away to some extent and thermodynamic effect was picked out. From the result, occurrence resin of cavitation was suppressed in 70°C hot water, where it is empirically known that thermodynamic effect does not appear in such a low temperature. The result indicates that thermodynamic effect and scale effect, which are conflicting effects, cancelled each other in water at 70°C. Additionally it was shown that occurrence of cavitation was drastically suppressed in a condition of specific angle of attack.

Fluctuating pressure (p’ ) of a large-scale vortical structure generated in a semiconductor single wafer spin cleaner was detected by using microphone array. Twelve microphones were installed on the exhaust cover under the rotating disk of the cleaner with their interval of 7.5° or 15°. Power spectrum densities (PSD) of p’ were compared with those of fluctuating velocity measured by PIV for various rotation angular velocities to identify fluctuations due to convection of the large-scale vortical structure. Good agreement of PSDs indicates that the large-scale structure could be detected by using microphone. Cross-correlation of p’ measured at different positions revealed that the large-scale structure convected to the downstream in the rotational direction of the disk. The convection speed was about 12 % of the angular velocity of the rotating disk. Number of the vortex in the large-scale structure was also evaluated from the time-series p’ data. Time-space contour map was made for p’ based on the data measured at the different angular position, and showed periodical swept strip patterns. Presences of the strip patterns indicate the pressure disturbances were stably convected to the downstream. From this time-space map, two-dimensional Fourier transform efficiently extracted the number of vortices in the large-scale structure.

In the laminar-turbulent transition process of a mixing layer formed downstream of a two-dimensional nozzle exit, an analysis was performed based on various information measures. Shannon entropy, permutation entropy and Kullback-Leibler divergence were introduced, and former studies in which they were used in the turbulent analysis were then reviewed. In the present study, the probability distribution of time series of hot-wire output voltage data was obtained, then analyzed. The aim of the investigation was to clarify the effectiveness of the analysis for the transition and turbulent flow. In addition, equations which Shannon entropy must satisfy in the turbulent flow field were derived. The Shannon entropy of the fluctuating velocity changed monotonically in the downstream direction. Thus, it appears to measure the transition process in the mixing layer. The permutation entropy of the fluctuating velocity first increased, then decreased, then increased again, and decreased finally. It reflected the increase of the fluctuating velocity and change of fluctuation manner (from periodic to irregular fluctuation) during the transition process. The Kullback-Leibler divergence based on the probability density function of the fluctuating velocity increased first, then decreased downstream, and thus did not show a monotonic change during the transition process in the mixing layer.

A mixing of fuel with air in jet engine is studied by analyzing unsteady turbulent flow in a simplified flow channel which consists of the opposed jets in a cross-flow. The mixing behaviors of the flow have been investigated parametrically by using a momentum flux ratio between jet and cross-flow to find that the mixing performance was related with the momentum flux ratio. It was also suggested that the mixing performance was connected with the flow behavior of the opposing jets in their interaction area. Presently the frequency analysis is performed to elucidate the characteristics of unsteady opposed jets in a cross-flow. The results show that the Kelvin-Helmholtz instability and low frequency fluctuation exist in the opposed impinging jets. The strength of the K-H instability is about one-tenth of the low frequency fluctuation. The low frequency fluctuation is related to the circulation which is caused from the collision between opposed jets.

In order to reduce thermal resistance of power module system, Thermal Interface Materials (TIMs) have been used at the interface between baseplate of power module and heat sink. TIMs have an important role to reduce thermal resistances due to solid surfaces with roughness or waviness. Thermal grease is a primary candidate to fill the gap between them. The grease can be pumped out of the gap during thermal cycling while the grease has the advantages of reduced cost compared to the other TIMs and TIM’s thickness. New reliability test of the grease is required for thermal management as the pump-out phenomena cause an increase of the thermal contact resistances. This study shows a visualization test method to evaluate pump-out phenomena of the grease during thermal cycling. A bimetal plate consisting of copper and invar is used to simulate thermal deformation of baseplate in power module. The grease is filled between the bimetal plate and Al thick plate, and then thermal cycling test is conducted. A 25 MHz ultrasonic imaging is used to visualize the grease layer. The ultrasonic images show a sequence of the grease behavior after the thermal cycling. The ultrasonic imaging results indicate that voids occur in non-curing grease under repeated pressure while cracks are detected in curing grease. It is also found that the curing grease layer applied in power devices can be designed by the evaluation of initial thermal contact resistances at the interface. Sensitivity analysis of correlated factors shows pump-out phenomena are strongly affected by curing of grease.

A laser 2-focus velocimeter (L2F) was used for measurements of velocity, size and number density of droplets in diesel sprays injected into the atmosphere by using 8-hole injector nozzle. The diameter of the nozzle orifice was 0.112mm. The injection pressure was set at 65MPa. The droplets dispersion model which can estimate the number density by using the spray width and the droplet velocity was proposed. It was shown that the velocity of droplets at the spray center region was higher than the one at spray periphery region in the middle period of injection duration. The size of droplets at the spray center region was larger than the one at the spray periphery region. The number density of droplets was high at the region between the spray center and the spray periphery. The number density estimated by the droplets dispersion model was nearly same as the one evaluated by L2F measurement at the spray center region in the middle period of injection duration. It is understood that the number density was decided by the dispersion due to the changes of the spray width and the spray velocity at the center region in the middle period of injection duration.

The heat transfer between exhaust gas and working fluid in a series of helical tube installed in a combustion furnace was analyzed numerically in order to discuss the development of heat recovery system combined with a small size combustion furnace. The dimensions of the equipment were about 0.49 m³ volume chamber with 2.5 m height chimney where the 250 m helical tube piping was available. The assumption of uniform gas side temperature referenced by the CFD simulation was used for simplify of the gas-side analysis. The inside heat transfer rate with phase change of working fluids were estimated numerically. The amounts of generation vapor and the effective tube length of pressure drop and the isentropic theoretical thermal efficiency on T-s diagram for water and hydrocarbons were also analyze for the discussion in comparison.

Although PID control is still widely used in the industry, it isn't answered a high performance demand. On the other hand, the model predictive control (MPC) is paid attention as effective control but it takes much cost to introduce MPC instead of the PID control since the MPC structure quite different from the PID control. To defeat such situation, this paper proposes a model predictive PID Control method. In this method, the PID control gains are derived by solving the constrained optimization problem based on MPC algorithm without using inverse matrixes. The numerical simulations show that the proposed method is effective for various control systems.

The present paper discusses on an automatic spinach harvester with a root cutting blade whose position and angle are automatically controlled. The position control of the blade is performed with a mechanism controlling the arm length and the angle control is executed by a mechanism controlling the angle of the blade. The path the blade moving is important for successful automatic harvesting; therefore specifying the appropriate commands to the angle of the blade as well as the length of the arm embodies the desired one. The present paper proposes a method to design an appropriate path of the blade based on the various desirable conditions in harvesting by specifying commands to the angle of the blade as well as the length of the arm. The proposed path involves robustness for variation by accidental translational motion in vertical direction of the cutting blade. The effectiveness of the proposed path is verified in field tests.

This paper describes the settling time of an automatic balancer that uses magnetic fluid and magnets. The settling time was examined, both by experiments and calculations. The settling time was calculated from the trajectory of the magnets. Trajectory was calculated using the Runge-Kutta method. A prototype was fabricated to confirm the settling time, through an experiment. Theoretical calculation results generally matched with experiment results. Additionally, the influence of change in the number of magnet was examined. Measurement results confirmed that the mean values and standard deviations were 2.06 seconds and 1.98 respectively for the case of two magnets, whereas they were 1.55 seconds and 0.670 respectively for case of four magnets, indicating that the settling time was smaller for both values with the case of four magnets. Such results made it apparent that the case of four magnets offers a superior settling time and smaller variance. The same results were also derived from calculations. We confirmed that the balance correcting performance is influenced magnetic repulsive force of magnets by calculations. Automatic balancer with a superior performance of the balance correcting and settling time is proposed.

A new concept of HILS(Hardware-In-the-Loop Simulation) system for an electric motor using the real-time coupling analysis with rigid body system and hydraulic system is presented in this paper. From the fuel consumption improvement point of view, the electric drive system is applied to the construction machinery for improving fuel efficiency and reducing pollution emissions. In the development of the electric drive system, it is important to evaluate the dynamic characteristics of the electric motor and control system, then HILS provides an approach for efficient development. This HILS system can act the actual load on the motor by calculating the coupling system equations of motion with the rigid body system and the hydraulic system in real-time. The real-time simulation was conducted by newly developed simulation model that the rigid bodies were actuated by the linear hydraulic actuator. A test rig was developed following this concept, in which the load computed by real-time simulation of the actual digging operation on the hydraulic excavator was exerted to the electric motor. The test results with developed testing system were compared with the simulation results using the simulation model with the electric motor. It is demonstrated that the HILS system of the electric motor can realize the actual digging operation of the hydraulic excavator.

Measuring or calculating structural intensity affords us to understand the propagation paths of vibration and the amount of the transmitted power. In this paper, a new structural intensity measurement method is proposed, in which an angular rate sensor and an accelerometer are used. The results measured by the new method are compared numerically and experimentally with those by the 2-point method with two accelerometers. The 2-point method has the error due to the finite difference to calculate angular displacement from displacements at two points. On the other hand, the new method using the angular rate sensor does not have such error. It is demonstrated that the new method can measure the structural intensity in a beam structure as same as the 2-point method equivalently and more accurately through numerical simulation. Robustness against sensor noise / error is examined; the simulation result has shown that proposed method and 2-point method are both robust enough against regular sensor noise. Further, structural intensity measurement experiments of a simple supported acrylic beam are performed, and the results show that both method could measure structural intensity with similar accuracy.

Recently, robots are expected to support actions performed in a real-life environment in our daily lives. However, robots encounter several interferences while performing physical interactions, such as shaking hands, hugging, and holding various objects. Therefore, it is difficult for the robots to perform such actions flexibly owing to the unexpected noises associated with these actions. Humans, in contrast, can cope with various disturbances thanks to the flexibility of their body structure. It is suggested that this property can be realized by changing the passive dynamics depending on the situation and task. Passive dynamics can be changed using two important mechanisms. One is imparting a high degree of freedom, i.e., redundancy of joints. The other is to incorporate a multi-articular muscle, i.e., redundancy of actuators. Using these redundancies, several complicated movements and power adjustments can be realized. In this study, a human-like upper-body musculoskeletal robot comprising redundant joints and actuators is developed. The robot can change its passive dynamics by simply changing the mutual interconnection of air actuators. In this paper, we report the structure and performance evaluation of the robot. The response characteristics of the robotic arm under different combinations of actuators connections are presented.

This paper shows estimation of earthquake using destructive intensity (DI) value and its application to switching control for air type anti-vibration apparatus (AVA). Air type AVAs are used for suppression of vibration in precision machining field like semiconductor manufacturing. Since even slight vibration is not excused, seismic motion which occurs in rare becomes a problem. Previous work switched control of the AVA by using spectrum intensity (SI) value when seismic motino occurs. However, the calculation of SI value has computational complexity and requires long computation time. In order to solve this problem, observation points were created in the distance from the AVA. Since this method leads to the increase of cost, it is difficult for an enterprise to use observation points. This paper proposes control system which estimates property of earthquake using only location of the AVA. In particular, to estimate earthquake uses DI value instead of SI value. This value has a characteristic which is that the computation time is short. This approach estimates characteristic of seismic motion by using both DI value and property of the AVA. Moreover, control of the AVA is switched. Simulation results demonstrated that DI value estimates property of seismic motion faster than the conventional method and proposal method could properly switch controller of AVA in the same way as the previous method. In addition, using DI value to detection way of seismic motion proves that this way can switch faster than the conventional method.

This paper considers the performance improvement of pneumatic stage positioning. The pneumatic system, which consists of air cylinders, servo valves, and pipes supplying compressed air to a pneumatic stage, have parameter variation due to mainly air compressibility. It leads to low positioning repeatability. To compensate for this parameter variation, model following control (MFC) is employed for the pneumatic system. One of authors has previously shown the effectiveness of MFC. However, how to select desired model to follow and controller used for MFC (called “the model following controller”) is not considered sufficiently. Then this paper considers appropriate model and the model following controller from the viewpoint of transfer function. As a result of considerations, it is found that the model cannot be selected freely, as represented by reference model of model matching two degrees-of-freedom control system, but rather should be just equal to the pneumatic system. Furthermore, it is also found that a PID controller is better than a PI as the model following controller so as to improve transient response of MFC. Validity of the proposed model and model following controller are presented by pole-zero loci and experimental results. The effectiveness of MFC with both proposed model and model following controller is shown by results of repeated positioning.

In this paper, we report the use of sound-absorbing materials, specifically sound-absorbing structures of bundled rice straws, that are oblique arranged incident to the sound waves. In addition, we investigated the normal and oblique incident sound-absorption coefficients of sound-absorbing structures made of bundled rice straws in free space. In this study, we placed sound-absorbing structures made of bundled rice straws at an angle against the direction of the thickness in order to elongate the rice-straw element without increasing the apparent thickness. We then experimentally investigated the increase in sound absorption in the low-frequency range. The following conclusions were drawn. For test samples in which rice straws were arranged both in a normal direction and in an oblique manner, the value of the normal incident sound-absorption coefficient in free space was close to the results obtained using acoustic tubes. For test samples with rice straws arranged both in the normal direction and in the oblique manner, the sound-absorption peak of the oblique incident sound-absorption coefficient in free space was shifted to the high-frequency side compared with that of the normal incident sound-absorption coefficient and the sound-absorption curve became flat in the high-frequency range. These observations suggest that a sound-absorbing material made of rice straws functions in the same way as a sound-absorbing material that has pores on its incident face. We demonstrated that the use of an oblique arrangement of rice straws inside acoustic tubes and in free space can improve the sound absorption in low-frequency range without increasing the apparent thickness of the material.

This paper focuses on the development of a spring-suspended suction cup with buckled plate spring. The proposed idea is that the buckled plate spring is used for adjusting negative pressure of suction cup. Moreover, the stored elastic energy in the plate-spring compensates pressure loss when air inflow happens in the suction cup. Existing passive suction cups are difficult to keep attachment to rough surfaces, where there exists air inflow, however, the proposed idea is able to continue attachment in a small air inflow environment without any actuator or energy source. Therefore the spring-suspended suction cup is able to decrease weight, size, and energy consumption of the attachment mechanism. This paper presents calculation of attachment time of the spring-suspended suction cup, input energy needed to start attachment, and estimation of air inflow to suction cup. From numerical comparison and experimental verification, it is confirmed that the proposed idea maintains attachment force for a longer time than the volume-fixed suction cup that is commonly used.

The convex disk rotating along a V-shaped valley causes the excited vibration in a rolling motion. This report represents the mechanism of generating this rolling vibration through an analytical model and the observed results using a simple apparatus. The author makes clear through investigation that these phenomena are derived from the friction induced between the disk and the tilted surface of the valley and that the rolling motion is generated because the rolling moment due to this friction varies synchronously with the rolling angular velocity. Further it is revealed that the greater the frictional coefficient is, the more this vibration is excited, and that the case of the tilted slope with a meeting angle beyond a certain limit of both sides of the valley does not generate these excited behaviors. A sphere instead of a disk behaves simple rotation along a slope without vibration. When this excited vibration in a rolling motion grows severer, the perpendicular resistant force on either surface of the slope of a valley becomes zero alternately. These analytical results tend to coincide with the ones observed on the apparatus. This mechanism inducing the excited vibration is expected to be applicable for polishing the stones of “go” or the convex lenses efficiently and for selecting the medical tablets with poor quality.

In high-rise buildings, the elevator rope may resonate with the building's sway induced by wind forces and/or by long period ground motion. Therefore, suppression of elevator rope vibration is desired. To gain an understanding of rope sway, the free vibration analysis of the string with vibration suppressors have been studied. In previous paper, an exact solution to the free vibration of the string with vibration suppressors located at 1/N from both ends of the string has been studied in the case where gap between string and vibration suppressor is zero. However, in the case where N is an even number and gap between string and vibration suppressor is not zero, no exact solution of the free vibration has yet been obtained. In this paper, an exact solution to the free vibration of this case is presented, when center position of the rope is pulled. The rope is modeled with string. Finite difference analyses of the rope vibration with vibration suppressor are also performed. The calculated results of the finite difference analyses are in good agreement with those of the exact solution.

This paper presents a numerical solution to multi-objective shape optimization in order to achieve stiffness maximization in thermoelastic fields. Compliance evaluated by thermal deformation based on temperature distribution and by mechanical deformation based on surface force or body force is used as an objective functional by using weighting method. Shape gradient of the multi-objective shape problem is derived theoretically using the Lagrange multiplier method, adjoint variable method, and the formulae of the material derivative. Reshaping is carried out by the traction method proposed as an approach to solving shape optimization problems. Numerical analyses program for the shape optimization is developed based on FreeFem++, and the validity of proposed method is confirmed by results of 2D numerical analyses.

Radio knives are common tools in surgery. The adhesion of the tip of a radio knife to the human body through the coagulation of blood is a severe problem. A solution to this problem, suggested by other authors, is to cool the tip of the radio knife. However, introducing a cooling system, such as circulating water inside the tip with a pump, requires additional wires and pipes and may also distract the surgeons. To overcome these issues, we consider the possibility of embedding a separate type thermosyphon to cool the radio knife tip without any additional wires and pipes. The important parameters are the tip length, tip diameter, inner tip diameter, enclosure ratio of the working fluid, and grip length. First, to clarify the heat-transport possibilities, the top of the tip of a separate type thermosyphon radio knife was heated by a ceramic heater; this was done to measure the temperature difference between the radio knife tip surface and a heat release part. Second, suitable values for the tip length, diameter and other important parameters were considered. It was concluded that the highest cooling efficiency is obtained when the heating area is limited between 200 and 250 mm² of the knife tip surface area. The inner pipe was indispensable to transport generated heat from the tip to the radio knife end. Consequently, it was revealed that the effective diameter of inner pipe was 0.48 mm in this research. To simulate the conventional surgery situations, the radio knife tip was immersed to blood and applied voltage to generate heat at the tip. It demonstrated 45.9 degree C at the maximum temperature while it was activated. Furthermore, the coagulation at the peripheral of the tip was observed, accordingly, the separate type thermosyphon radio knife exhibited a stop bleeding ability.

Currently, pumps are used in various fields to supply air and liquid. These pumps include sliding parts and there is a limit of life time due to friction and wear. To solve this problem, a number of pumps using ultrasonic vibration have been proposed. A common feature of ultrasonic pumps is having no sliding parts. Therefore, the life time seems longer than those of the conventional pumps. In the present study, we found an occurrence of pump effect when an opposing block faces ultrasonically vibrating surface with a small gap. The ultrasonic transducer has a hole to provide the path for fluid flow and the opposing surface was a tapered end of an aluminum cylinder. According to the measurement results of gauge pressure, when circumference of the opposing block is tapered, air was discharged from the gap of two surfaces. On the other hand, when center of the block is tapered, air was sucked into the gap. Microscopic quasi-static behavior of the two surfaces is observed by using a digital microscope during pump operation.

Blank shape minimizing earing, which is trimmed off after forming, is an important issue in sheet metal forming. In addition, blank holder force (BHF) have an influence on the product quality. Recently, variable BHF (VBHF) that the BHF varies through punch stroke is recognized as one of the advanced forming technologies. Furthermore, segmented VBHF will be valid to complex shapes for successful sheet metal forming. However, the optimal segmented VBHF trajectories and the optimal blank shape minimizing the earing are unknown in advance, and consequently the trial and error method is widely used to determine them. To resolve above issues, in this paper, a simultaneous design optimization of the blank shape and the segmented VBHF trajectories is performed. Numerical simulation in sheet metal forming is so intensive that a sequential approximate optimization using a radial basis function network is adopted to determine them. Based on the numerical result, the experiment using AC servo press is carried out. It is confirmed from the numerical and experimental result that the proposed approach is valid.

Dolphin kick swimming is an underwater undulatory motion which is similar to the way dolphin and other cetaceans swim, and it's utilized after dives and turns in competitive swimming. Since in the international rules underwater limit is 15m which is 30% of 50m pool, this swimming technique has large effect on swimming records. Thus, it is essential to know and control fluid dynamics of dolphin kick swimming. In this paper, flow around human in dolphin kick swimming is simulated and the results are evaluated. To implement the simulation, dolphin kick movement is reproduced on computer by 3D model of male swimmer and changes of 5 joint angles are captured from the video footage, and the flow around swimmer model is computed by means of a moving grid finite volume method. This computational approach completely fulfills geometric conservation laws, so that moving boundary problems become resolvable. Also, a moving computational domain method actualizes unrestricted move of swimmer model. Furthermore, coupling of these methods and kinematics allows swimmer model to dynamically accelerate and decelerate by the forces applied to itself. The result shows that most of the thrust is produced in down-kick, and the ring vortex is generated in the wake, which appears in practical dolphin kick swimming. And the speed of swimmer model agrees with the speed of swimmer in the video footage.

Recently, AACN (Advanced Automatic Collision Notification) that presupposed cooperation with emergency life-saving organizations is expected. Therefore, emergency life-saving organizations must recognize injury speciation of patients, as quickly as possible. So, the author tried the traffic accident analyzing method by statistical data analysis from combing analysis items analysis items for main site of injury and analysis items for injury contents (indicated in the traffic accident statistics vote by Japanese National Police Agency). And furthermore it is necessary to improve the safety of vehicles not only for same class collisions but also for collisions between vehicles of different types (e.g., between SUVs and sedans). In this study, the author applied the method of analysis as described above for frontal collision between SUVs and middle sedans, and analyzed using statistical data stored in ITARDA (Institute for Traffic Accident Research and Data Analysis). In the case of fatal or severe injuries, it is shown that the component rate of chest fracture of middle sedan drivers is higher than that of SUVs. It is supposed that the difference in these rates is caused by the vertical offset configuration between the frames of the two different types of vehicles when they crash into each other.

Fundamental study on a method to reduce the primary bending vibration for magnetically levitated (maglev) vehicles is conducted. These vehicles composed of lightweight car bodies are subject to elastic vibration; therefore, reduction of bending vibration will have considerable effect on ride comfort. First, a vehicle dynamics simulation model that can simulate bending car body is constructed to compare and analyze with the resonance characteristics of actual car body vibration in the field test. Then, this paper presents the optimal specification of the anchor, a coupling element between the car body and the bogie, to reduce the primary bending vibration. The validity of the calculation method of the specifications is verified by frequency response analysis, eigenvalue analysis, and vehicle dynamics simulation. Next, a test stand consisting of one-third segment car body to simulate the primary bending vibration is developed utilizing hardware-in-the-loop simulation (HILS). The results of swept sine excitation experiments confirm that the one-third car body can simulate the primary bending vibration of a full-scale car body with the HILS system. Finally, fundamental experiments are conducted in the test stand to reduce the primary bending vibration. The experimental results show that the optimally-designed anchor can reduce the primary bending vibration.

A new concept of twistable morphing spar is proposed to achieve an objective distribution of the twist angle more arbitrary and validity of the proposed design method is confirmed through experiments and numerical simulations using finite element analyses. A key aspect of the proposed twistable morphing spar concept is a double cylinder consisting of two cylinders, which is employed as a spar of twistable morphing wing. The ends of these cylinders are connected to each other at the tip side. One cylinder (Inner-cylinder) is a thick closed-section member. It carries torsion moments and connected to motor that provides moment to the member at the root side. The other cylinder (Outer-cylinder) is a variable-shape member composed of open and closed-sections. It is designed to achieve an objective distribution of twist angles, and is connected to the aircraft fuselage at the root side. The objective distribution of the twist angle can be achieved by designing the parameter we selected appropriate. In accordance with the design method, we manufactured an experimental model using a 3D printer and twist experiment was carried out. From comparison of the experimental results and the numerical simulation, feasibility of the twistable morphing spar and the validity of the design method were confirmed.

In this study, fundamental experiments for docking method by loading an anchor on satellite structures were carried out and the effects of the anchor shape on the docking properties were investigated. Through the projectile experiments and pull-out experiments, fixing conditions of some projection velocities and the pulling strengths were evaluated. Four types of metal anchors were employed to examine the influence of the anchor shapes on the penetrating performance and pull-out strength. In anchor projection experiments, the effect of projection angles and anchor tip angles on penetrating performance were investigated. The experiments with projection angle up to 30 degree using 2 anchor tip angles were performed. Through the experiments appropriate projection velocities were investigated based on the kinematic energy of the projectiles. It is observed that the anchors did not penetrate to the sample structure when the projection velocities were not sufficient and the anchors passed through when the velocities were too high. Besides, when a projection angle was small compared with a half of tip angle, the metal anchor cannot penetrate into test plate. In the pull-out experiments, the usages of narrow section and large umbrella portion have been proposed and their effectiveness was investigated. The results of the pull-out experiments indicate that the shapes of the anchors affects the pulling strength and the narrow section enlarges the pulling strength. Sufficient tensile strengths of docking for removing space debris were obtained by using a projectile anchor with the appropriate conditions. The effectiveness of docking with satellite structures using the anchor with the appropriate shape was demonstrated through these experiments.