KUKAI is a pico-satellite developed by Kagawa University and was launched by the H-IIA rocket by the Japan Aerospace Exploration Agency (JAXA) on 23 January 2009. The primary objective of KUKAI is technical verification of a tethered space robot, which is a new type of space robot system proposed in previous work. KUKAI consists of mother and daughter satellites for tether deployment. This was the first time to launch mother-daughter satellite among pico-satellites less than 10kg in the world. Then, it is important to develop separation mechanism. The separation and the launch lock mechanisms for KUKAI have been developed, and confirmed and evaluated by launch environment and microgravity condition.

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Lately, ecological and intelligent colloidal dampers based on the liquid penetration/exudation in/from lyophobic nanoporous solids were proposed. Although colloidal dampers could be attractive for various applications, they are still under research, since some unexpected findings await satisfactory explanation. For instance, colloidal dampers are able to dissipate large amounts of mechanical energy without significant heating, and such result is surprising since traditional absorbers transform almost integrally the dissipated energy into heat. In this work, using a digital infrated-camera, the temperature distribution on the external surface of a colloidal damper is recorded versus the working time and the positions of the main heat sources are identified. Such experiments allow evaluation of the temperature inside the colloidal damper's working cylinder and the absorber's generated heat. Introducing the colloidal damper inside of an incubator, variation of the hysteresis shape and dissipated energy varsus the working temperature can be found. From such experimental results, ratio of the generated heat to the dissipated energy is evaluated.

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This paper presents the vibration analyses of truss core panel. Truss core panel is newly devised lightweight core panel and has general versatility. The vibration analyses and excitation experiments to obtain the vibration characteristics such as natural frequency and natural mode are conducted. As a result, comparing with the flat panel which weight is equal to the truss core panel, it is proved that truss core panel has tremendously high natural frequency compared with that of the flat panel. It is expected on the process of generalization bending rigidity of truss core panels can be underestimate because the stiffness of the truss core panel at the edge parts is less than that of core parts of the panel. Therefore in order to consider the effects of edge parts, bending rigidity of six different size panels with same wide edge are analyzed and proved that by enlarging panel size, the proportion of edge parts become relatively less and the bending rigidity per ideal sandwich panel close in to constant number, over 42%. On the other words bending rigidity of the truss core panels, which edge parts are not nominal, can be underestimate.

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This paper proposes an analytical method for elastic buckling of laminated composite plates with local anisotropy induced by curved reinforcement fibers. The local anisotropy accounts for non-homogenous stress distribution within the plate when it is subjected to in-plane loads along the boundary. An in-plane elasticity problem has to be solved first to determine the in-plane stresses, and these stresses become input to the buckling problem. Both in-plane and buckling problems are solved independently by using the Ritz method with algebraic polynomial displacement functions. In numerical results, the present results agree well with those from the finite element method, and the present plates with specific curvilinear fibers show higher buckling loads than plates with conventional straight fibers. It is therefore confirmed that the locally anisotropic plates with curvilinear fibers have strong possibility to improve the buckling performance over conventional materials with straight fibers.

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The fiber reinforced plastics are widely used in engineering structures because they have excellent features of high specific strength and stiffness ratio. These advanced composites are fabricated typically by stacking orthotropic layers, each of which is composed of reinforcing fibers and matrix material. In this work, an optimum design approach is proposed to deal with multi-objective design for buckling behaviors of laminated composite plates. The approach consists of two parts: the first part is to calculate the influence factors and determine the estimated model of each objective function by using design of experiments, and the second part is to explore Pareto sets from the estimated model. In numerical examples, the fiber orientation angles of symmetrically laminated plate are optimized for maximizing the buckling parameters simultaneously for two different compression loadings. It is shown that the proposed approach is quite effective in obtaining Pareto sets with reduced calculation cost. Moreover, the influence analysis found that outer layers are more effective than the inner layers, and the interactions between adjacent layers are also important on buckling behavior of the laminated plates.

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The formation of vibration absorbers in a thin gauge structure is proposed to reduce sound radiated from the structure. The absorber is considered as a free-free beam made of a steel plate which is fixed to the structure at its midpoint and whose anti-resonance frequency is tuned to the excitation frequency. In this paper, the method for evaluating an equivalent mass of the absorber at its anti-resonance frequency is proposed to predict sound reduction. And it is showed that the application of this method to the multi jointed type of the absorber with zigzag shapes which has multiple anti-resonance frequencies is able to reduce the exciting force with the high order components.

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In this paper, we present a numerical solution to optimize a cross section shape of a solid structure, which is often demanded at the early stage in structural designs. The cross section area is minimized subject to the constraints of sectional properties including the torsional constant, the second moment of area, the center of figure and the boundary length. The problem is formulated as a distributed shape optimization problem, and the shape gradient function is derived using the Lagrange multipliers and the material derivative method. The traction method, which was proposed as a gradient method in the Hilbert space, is applied to determine the smooth optimal shape. The constraint conditions are efficiently satisfied using the modified feasible direction method. The validity of this method is verified through several design examples for obtaining the optimal shape of the cross section under the constraints of sectional properties.

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This paper is concerned with the active wave control of a rectangular panel. It is the purpose of this paper to present a wave filtering method for the panel using shaped smart sensors and its application to an adaptive feedforward control system. Firstly, the design procedure of the wave filter using shaped PVDF sensors is presented based on a wave solution of a rectangular panel. When introducing PVDF sensor, shaping function is defined as a complex function. In this case, an imaginary unit is realized by the phase shifter of 90 degrees. Next, from a viewpoint of numerical analysis, the accuracy of the wave filter and the performance of the control system are clarified. Finally, an experiment of the active wave feedforward control system is carried out, demonstrating the validity of the proposed method.

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In this research, we propose the driving method of the magnetic material disc by the rotating magnetic field. When the rotating magnetic field is given to the magnetic material disk, the magnetic material disk is magnetized by a phase different from the rotating magnetic field. Therefore, magnetic attractive force acts between the magnetic material disk and the rotating magnetic field. At this time, because force in the vertical direction and radial direction cancelled respectively, only force in the circumferential direction comes to act. The rotating torque is generated by this force in the circumferential direction. Therefore, the magnetic material disc rotates. The purpose of a present article is to clarify the proposed driving principle by doing the magnetic flux density measurement, torque measurement and the torque analysis. Then, this driving principle was clarified to some degree.

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Recently, bladed disks with continuous ring type structure have been used in many kinds of turbo-machinery due to its high reliability. This paper, first, presents a simple analysis method for estimating vibration response characteristics of a bladed disk with continuous ring type structure losing a shroud and a stab. Second, the parametric study on the vibration response characteristics of a bladed disk losing a shroud and a stab is carried out utilizing the analysis method proposed here. From the calculated results, the vibration response characteristics of the bladed disk are clarified. Lastly, the results calculated by the simple analysis method proposed are compared with the results obtained from FEA in order to verify the analysis method.

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In this paper, a calculation method was proposed, by which the equivalent creep coefficient for the case where there exist plural contact points between wheel treads and rails can be estimated. By using this proposed technique, the equivalent creep coefficient was estimated for the actual wheel profiles of the commuter train. The simulation was also carried out in order to find out how the difference of a value of an estimated creep coefficient has influence on the running stability of railway vehicle. As a result, it was shown that it is important to estimate a creep coefficient precisely for evaluation of running stability of railway vehicle.

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In this study, the authors have investigated how non-structural members in the carbody influence on the rigidity and the vibration characteristics of a commuter type railway vehicle. "Inner ring" sub-structures, which are composed of reinforcing beams on the floor, side and roof structures and evaluated in the previous study, are attached to "Rigidity Test Car", which have been designed and manufactured for above purpose. Static load and excitation tests have been performed, and the results have shown that the proposed inner rings have largely affected the natural frequencies, vibration shapes and response accelerations of the carbody. The additional mass have been then reduced by replacing the whole inner rings with just the ceiling frames aiming at putting them to practical use. It have been verified that the rails for hand straps are also effective to improve the rigidity of the carbody when these are properly attached to the carbody.

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Flywheel was considered as long life and high energy density auxiliary power source in hybrid traction system of railway vehicles. However, it is necessary to evaluate the gyro-dynamic interaction between current vehicle and additional flywheel. This paper proposes a new method on tilting control of railway vehicles using gyroscopic moment obtained from onboard flywheel primarily used as the auxiliary power source. In order to prevent comfort deterioration in transient process of pendulum railway vehicle, active tilting control torque is demanded. The authors developed a simulation model and conducted an examination of railway vehicle considering onboard flywheel as a controllable gyroscope.

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This paper proposes SSM (Sensor Steering Mechanism) for a lateral guided vehicle with an articulated body which is allowing the vehicle to change moving directions. Authors demonstrate the geometry of SSM for a front wheel steer type, reverse phase four-wheel steer type and rear wheel steer type vehicle. SSM presents the stable lateral guiding performance for automated vehicle which follows a straight and curved path created by guideway. The other hand, SSM is not established for articulated vehicles such as wheel loaders and dump tracks used in the mine and construction site. SSM for an articulated vehicle enables a wheel loader to automated moving on every spaces. This paper leads SSM for an articulated vehicle and constructs an experimental robotic vehicle with proposed SSM. Simulated and experimental data show the advantages of proposed SSM.

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In recent years, it is reported that passenger's dynamics and vibration characteristics to the multidirectional vibration at sitting position are different from a driver. However, there are few researches about a suspension control which considers these dynamics of human body characteristics and sitting position. In this paper, new semi-active suspension control method is developed to reduce passenger's vibration and motion. Firstly, a vehicle and passenger model including the dynamics of human body and sitting position is constructed. Second, the robust control system design method which uses the vertical acceleration of a passenger's head to one of the amounts of evaluation function is proposed. In order to control the jerk which is generated by changing of a damping coefficient rapidly, the robust controller is designed based on Lissajous figure of damping force. From the result, it was confirmed that in nearly the resonance frequency of vertical direction of a passenger's head (vertical direction), the proposed control method is effective in reducing a passenger's vibration better than the general control method which uses a vartical acceleration of the vehicle body as the evaluation function.

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Centrifugal pendulum vibration absorbers are widely used as the vibration suppression devise for helicopters. The vibration characteristics of this absorber has been investigated by applying the linear theory on anti-resonance. However, the nonlinear characteristics appear when the pendulum swings with large amplitude. The authors studied vibration suppression characteristics of pendulum absorbers considering nonlinear characteristics of pendulums. In the first report, we investigated a two-degree-of-freedom system composed of a rigid rotor blade and a pendulum. In this system, the blade was excited by a harmonic deflection motion of the shaft. In the second report, we investigated a three-degree-of-freedom system composed of a fuselage, a rigid blade and a pendulum. In this paper, the model has three degrees of freedom and is composed of a blade, a pendulum and a rotor mount. The blade is flexible and only the first mode is considered. An aerodynamic excitation force applies to the blade. The vibration suppression characteristics of this system are investigated theoretically and experimentally.

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A crane mounted on a tower-like flexible structure called Tower Crane has a problem that fast transfer of the load causes the sway of the load and the vibration of the flexible structure. Our objective is to reduce both the sway and the vibration using the controller for motors which drive the boom, while an operator gives some commands to transfer the load. We have proposed the gain-scheduled H_∞ control method to design the controller, and have already shown its efficiency for a one-thirty fifths scale model of the tower crane. In this paper the controller for an actual tower crane is designed and implemented in the existing control system and its effectiveness is verified from the experimental results.

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The paper introduces the new method to estimate vertical road roughness from accelerations and suspension strokes of the automobile using ICA (Independent Component Analysis), and examines the performance through the numerical simulation. The authors propose to apply ICA to monitor the automobiles. ICA only presumes the independency of source signals, so it is expected that ICA can identify the road roughness without specifications of a car. To simplify the discussion, only vertical and pitch motions are considered. The integral of strokes, velocities, and differential accelerations are calculated by integrating and differentiating the measured accelerations and suspensions strokes, respectively. They are treated as parts of the observed data sets as well as the accelerations. By using ICA, the similar shape to the input road is estimated.

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In case of an earthquake, an electric-railway pole that supports overhead contact lines oscillates. Especially, when natural frequency of a viaduct and that of a pole coincide with each other, resonance occurs, and there is a possibility that a pole collapses. A damping device for electric-railway pole has been invented in order to reduce the vibration caused by an earthquake or passing train. The authors conducted theoretical analyses of pole response equipped with the damping device and vibration test of real scale pole. The damping device is a sandwich structure consisting of a steel plate and a visco-elastic body, which has damping effect even for minute displacement. The result of theoretical analyses has been found to be almost identical to the result of vibration test. Moreover, as the result of vibration test, damping effect of the device has been verified.

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In order to protect precise machinery from external vibration, various types of vibration isolation system have been proposed by many researchers. For the passive isolation system, a friction damper is often used because it is simple, inexpensive and reliable. However, the ordinary friction damper of constant friction force has performance limitation, because the isolation characteristic declines when the friction force is large, while resonant peak becomes large when the friction force is small. Furthermore, the displacement remains apart from the equilibrium position after the disturbance disappeared. These characteristics are disadvantageous when the precise position recovery is required. In order to overcome above drawbacks of the ordinary friction damper, the new type of friction damper is proposed in this paper. In the new friction damper, the friction lever mechanism is devised to make the magnitude of the friction force proportional to the relative displacement. This is achieved by contacting the inclined lever with rotational spring to the cylindrical block. When the cylindrical block moves and the angle of inclination of the lever varies, the normal and frictional forces at the contact surface vary according to the displacement of the cylindrical block.

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Collision Mitigation Brake (CMB) is a part of the Pre-crash safety system intended to mitigate damage during vehicle collisions. In this study, the effects of CMB system on vehicle rear-end collision accidents were investigated. To this end, a dynamic vehicle simulation model was constructed, in which the sensor and the CMB model were built. By using this model, the reduction of collision speed by the CMB system was evaluated numerically. Here, the road surface friction coefficient is considered to have a large influence on the CMB. In addition, the Time to Collision (TTC) which is the judgment line of the brake initiation is the key factor to the efficient operation of CMB. Therefore, simulations were carried out on road surfaces with different friction coefficient and CMB system with different values of TTC. Generally, the effect of CMB is expected to increase with the rise of friction coefficient of the road and the value of TTC. A larger value of TTC will be preferred for the cases of roads with low friction coefficients. However, collision avoidances might occur when the large value of TTC is employed in low speed collisions. Finally, the findings reveled that the value of TTC should be controlled in such that the value is increased for roads with low friction coefficient and decreased for low speed collisions.

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In this paper we address an integrated design problem of semi-active controlled civil structures with Vibration Control Device (VCD) that has been developed by authors. A new semi-active control law based on a one-step-ahead prediction of the seismic response is proposed. The VCD generates two types of resistance forces, i.e., a damping force proportional to the relative velocity and an inertial force proportional to the relative acceleration between two stories. The damping coefficient of the VCD can be changed with a command signal to an electric circuit connected to the VCD. In the present paper the command signal for changing the damping coefficient of each VCD is assumed to take two values, i.e., the command to take the maximum or minimum damping coefficient. The optimal command signal is selected from all candidates of command signals so that a norm of the one-step-ahead predicted seismic response, calculated by a numerical integration, is minimized. Under the semi-active control law the stiffness distribution between neighboring two stories of the structure, design parameters of the VCDs and those in the semi-active control are optimized so that the seismic responses subject to various recorded and artificial earthquake waves are optimized. Genetic Algorithm (GA) is adopted for the optimal design. A simulation example of a fifteen-story building with three VCDs is presented. With the proposed integrated design method structural parameters and the semi-active control law that achieve the good control performance have been obtained.

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The purpose of this paper is to propose one analytical method to make stochastic floor response spectra in order to easily estimate the dynamic characteristics of secondary system such as piping, equipment and so on, mounted on a class of nonlinear viscoelastic structures owing to a severe earthquake. The nonlinear properties of the structures are modeled in terms of an equation of motion which linearly involves the auxiliary variable as part of the restoring force and the auxiliary equation which describes a nonlinear relationship between the auxiliary variable and the structural response. Total equations including the auxiliary equation are linearized using a stochastic linearization technique. Then executing the statistical calculation to obtain the non-stationary variance relating to relative displacement of secondary system and utilizing a newly proposed idea to estimate the extreme value, finally the stochastic floor response spectra can be derived. The analytical results are compared with those by Monte Carlo simulation.

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The evaluation methodologies for the flow-induced vibration of an elastic beam due to the axial flow in confined narrow passage are reported. One of authors has already proposed the analytical method using Navier-Stokes equation for the dynamic stability of elastic beam subjected to axial flow in confined narrow passage. In this paper, by using this proposed analytical methods, we perform the numerical studies taking three kinds of support conditions as parameters, that is a cantilever fixed at the upstream side, a cantilever fixed at the downstream side, and a simple supported beam at the both sides, respectively. Moreover, we perform also parameter-studies concerning with a width of annular gap, viscosity of a fluid, and structural damping. And we clarify the effects of support conditions of structures, structural damping, and fluid characteristics on the dynamic stability of an elastic beam due to the axial flow in confined narrow passage for proposing the safety dynamic design guideline concerning axial flow-induced vibration in industries.

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Signing for tracked vehicles that are operated on non-pavement road or soft ground, it is important to analyze the interaction between a machine and soil. In this research, attention was focused on the interaction under front-idler, that is, traction soil by a grouser in driving system. To verify the validity of interaction analysis between a grouser and soil by using 3-dimensional DEM soil model, traction simulations and experiments were carried out. In addition, the soil model was considered particle roughness to introduce compaction effect by compression. To check the effectiveness of the soil model, compression test and shearing test were conducted. Consequently, soil behavior and porosity change were found on the tests. And comparing the results of traction simulations and experiments, soil behavior and qualitative characteristics of traction resistance were conformed. Therefore, interaction between grouser and soil cloud be analyzed by using the soil model considered particle roughness.

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In this paper, we propose the optimal seismic design methodology which can consider the soundness of elasto-plastic dampers in addition to that of the piping systems. This methodology employs genetic algorithm and can search the optimal conditions such as the number of supports, supporting location, mounting angle and capacity of dampers. Five types of evaluation functions are considered. As the results, it is found that it is very important to optimize the mounting angle of dampers for the piping systems subjected to the actual seismic waves with particular frequency components.

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A remote motion control method for micro vehicles by two-way laser communication technology is proposed in this paper. The vehicle receives operation commands as pulse frequency modulations of a pulse laser radiated from the light source base. The laser is also used for laser tracking to chase the position of the corner-cube reflector equipped on the vehicle. At the same time, the vehicle sends its position information to the base with a MEMS (Micro-Electric-Mechanical-Systems) mirror equipped on the vehicle. The MEMS mirror transmits the information signal as light-path frequency modulations of the reflected laser beam. An advantage of this system is that the all these functions are achieved by a single laser source, resulting in the simplicity of the mechanism and the weight reduction of the micro vehicle. An experiment with a wheeled vehicle is carried out and the effectiveness of the proposed system is verified by achieving the motion control of the vehicle.

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There are several approaches for the jump mechanism of the robot. Compressed air and coiled spring are usually utilized for the power source of the jump robot. In this paper, the jump mechanism for the robot using the leaf spring and motors is examined. This actuator system can be applied to the smooth motion and the jump motion. The author developed the computer simulatior of this actuator system. The beam element considering the motion of the large displacement motion is applied to model the leaf spring. The simulation results are shown to evaluate this simulator.

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A theoretical analysis is presented to investigate the nonlinear dynamic behavior, i.e., the stability and unbalance response of bump-type foil bearings. The link-spring model, presented and validated in a previous study, is used to describe the foil structure of bump-type foil bearings in this research. The orbit of the shaft is simulated from the iteration calculation of the motion equation at each time step, which is coupled to the Reynolds' equation and the foil structure model. Parametric studies on the mumber of bumps, the size of bumps, the thickness of the foils and the material of the foils are presented using the bearing load prediction and the nonlinear orbit simulations. The static loads of the foil bearing with various parameters are predicted to find out some guidelines for the design of foil bearings. The critical speeds of the rotor with a certain bearing load are also calculated. The analysis on unbalance response is presented by depicting journal trajectories as a function of mass unbalance. And the FFT analysis of the computed results is performed to show the variation of amplitudes in frequency domain.

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Analytical results are presented on nonlinear coupled vibrations of a system of a rigid rod supported by parallel strings. The governing equation of the system includes nonlinear coupling between in-plane, out-of-plane and pitching motions. Nonlinear periodic responses are calculated with the harmonic balance method. Time responses of the system are calculated by direct numerical integration with the Runge-Kutta method. As the excitation frequency is increased, vibration form changes from in-plane periodic vibration to whirling, and then quasi-periodic responses appear accompanied by whirling and pitching motion. At the specific frequencies in the region of quasi-periodic responses, chaotic responses are also observed. As the excitation frequency is increased further, the vibration form transits to periodic pitching vibration with the jump phenomenon. It is found that the frequency region of the quasi-periodic response is narrowed as the eccentricity of the rod is increased. Furthermore, the region of the quasi-periodic response is slightly enlarged by the increase of the distance between the two strings. The variation of the frequency region of the quasi-periodic response has close relation with that of the periodic response of pitching motion.

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On active noise control in 3-dimensional acoustic field, a control effect becomes worse when an evaluation point moves. Against this problem, we proposed a control algorithm using filter map. Validity of this algorithm was shown by simulations and experiments. To use the method, however, the adaptive filters must be accumulated in a controller so that the required memory becomes large. Therefore, reduction of required memory is necessary. In this paper, a method for the reduction is proposed. In the method, adaptive FIR filters is regarded as superpositions of several modes. At first, modal parameters of an optimal filter are identified. Prony's method and least-square method are used in this identification process. An ANC simulation using the identified parameters is carried out. According to the result, the required memory is reduced about eighty percent. Moreover, an adaptive algorithm is proposed. The algorithm calculates amplitudes of modal parameters. Validity of the adaptive method is shown by simulations and an experiment.

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In this paper, a distributed control system for an active stabilizer and an electric power steering (EPS) is designed in order to improve the performance on vehicle agility and stability. A full vehicle simulation model with the active stabilizer and the EPS is derived and used to evaluate the performance for the distributed controllers design. A controller for the active stabilizer is designed using the linear quadratic (LQ) control theory to balance competing goals for the roll reduction of a vehicle body during cornering and the improvement of the ride comfort on a rough road and to especially take the road surface disturbance to the steering system into account. Also a controller for the EPS considering the self-aligning torque generated from the vehicle system with the stabilizer is designed to assist the steering of the driver by applying the H_∞ control theory. It is verified that the distributed control system applied to the full vehicle model is effective to not only reduce the roll motion and the steering torque during cornering but also improve the driving stability and the ride comfort on the rough road.

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In order to properly evaluate the effect of tensioning on a circular saw, it is essential to use the change in natural frequency of the sawblade tensioned by rolling. This paper deals with a spatial filtering technique called the modal filter to easily measure the natural frequencies for the modes necessary for the evaluation of tensioning effect. The modes necessary for the evaluation are indicated based on the backward travelling wave frequencies of a rotating disk. The modal filter using point sensors, is designed based on the mode shapes of a disk. The examples show that the natural frequencies for the modes with the nodal diameters 0, 1 and 2 are necessary for the evaluation of tensioning effect. The information on the nodal diameters for the disk allows to easily determine the proper sensor positions for the modal filter for a disk such as a circular saw. The modal filter designed extracts the three modes separately from the experimental data obtained in the impact test of the disk.

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A squeal test using a pad with a different thickness demonstrated that a squeal with a higher frequency can be generated if a thin pad is used. The factors that changed as a result of pad thickness were termed 'difference of pad rigidity' and 'dimension difference in the thickness direction of the pad', and the influence each factor exerted on the squeal was clarified. First, the dynamic stiffness of the pads used for the squeal tests were measured by adding a vibration that imitated the frequency and amplitude of the squeal. The measurement showed that the pad rigidity becomes hard when the pad thickness becomes thin. In addition, the pad vibrated with the same amplitude and the same phase from the frictional contact surface to the back plate in the thickness direction. The pad rigidity is in inverse proportion to the pad thickness because the pad can be viewed as springs in series in the thickness direction. Next, the influence that pad thickness exerted on squeal was analyzed by using a surface contact analysis model that reproduced the pad rigidity with a distributed spring and the dimension difference in the thickness direction of the pad with distance from the contact surface to the rotational center of the pad. Results showed that the squeal frequency becomes high when the pad rigidity becomes hard. If the dimension in the thickness direction of the pad becomes small, the squeal is not generated easily; however, the dimension does not influence the squeal frequency.

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Rubbers filled with carbon-black are often used for vibration and noise control. It is useful to model the dynamic properties of the field rubber for dumping treatments on the machine elements as panels, beams etc. However, the model expressing dynamic properties of the filled rubber is not completely constructed. This paper deals with modeling the dynamic properties of the filled rubbers and its parameters. First, the dynamic properties of the filled rubber are experimentally investigated. Next, it is verified that the experimental results can be expressed by the fractional model in small oscillation region that dynamic properties do not depend on strain amplitude. Finally, the relationships between the parameters and weight of carbon are investigated. As a result, the static modulus has a peak at carbon black of 30phr (part per hundred rubber in weight). Coefficients of viscoelasticity increase and the fractional orders decrease with increasing carbon black in phr.

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This paper deals with a theoretical stability analysis of an unstable wave generated on a thin film subjected to leakage-fluid flow. In the stability analysis, the structural equation of the thin film in the transverse motion is based on the Kirchhoff-Love's thin-plate model and the basic equations of fluid flow around the thin film are based on Navier-Stokes equations. The governing equations of the thin film motion coupled with fluid flow are obtained. As a result, the analytical results show that traveling-wave type unstable wave occurs to the thin film due to leakage-fluid flow and clarify the dispersion relation of the wave motion, phase velocity (traveling-wave velocity) and growth rate of the wave. Moreover, the analytical results are verified by experiments on the most unstable wave number and critical flow velocity.

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A tripod constant velocity joint is used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To determine mechanisms inducing the thrust force, a detailed model is constructed based on a multibody dynamics approach. Though the joint is equipped with three rollers and grooves, this model consists of principal parts concerned with one roller and groove in order to precisely analyze frictional phenomena occurring between the roller and the groove. These principal parts are defined as rigid bodies and are connected by force elements of contact and friction. The appropriateness of this model is verified by comparing computational and experimental results and it is clarified that the principal factors inducing the thrust force are three kinds of sliding friction force at a contact point between the roller and the groove. This paper also describes the reason that the third rotating order component of the thrust force is induced by one roller and groove.

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The basic part of packaging machine is the forming collar that provides the shape over which packaging film is smoothly formed into cylindrical shape. But designing the forming collar is a difficult job. This paper presents a flexible method for calculating the complete geometry of the collar, rather than the usually non-complete collar over which the film is formed. The collar geometry is calculated such that it has the minimum deformation energy. Among collar generation methods reviewed, the proposed methodology is the first one that could systematically consider all collar configuration parameters such as seam configuration, flat or straight part of collar, collar back angle, etc. A means for obtaining the exact collar geometry is also demonstrated. Some examples that are designed by using this method are presented, and some verifications of this method are presented by calculating ruling lines of them. Demonstration using prototype of the collar is also presented.

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This paper develops and improves the concise, accurate and general purpose oriented finite element model of an open crack in the rotating shaft. The decision of the parameter involved in this crack model is discussed and proposed, and it is verified by investigating the natural frequencies in both static and rotating conditions experimentally. Furthermore, the theoretical analysis of the double-frequency vibration due to crack is performed. Both the theoretical and the experimental resonance curves of the double-frequency vibration are compared, and their quantitative agreement is confirmed. As the result, the accuracy of the developed crack model of the rotating shaft and the validity of the theoretical analysis discussed in this paper are clarified.

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For considering countermeasure of the noise in vehicle cabin, structure-acoustic coupling analysis needs to be conducted. Recently, the operational state analysis is performed and more effective counter measure of the noise is enabled. Conventionally, the input identification under operational condition has been the first step to tackle with the problem. However, it is usually time-consuming and needs a lot of practical skills. Therefore, this paper proposes a new sensitivity analysis for the noise reduction under operational condition without using input identification. The structure modification is investigated based on the operational response, where the mass-added structure modification is considered as an example. The proposed method uses sensitivity analysis and response estimate after the structure change. It is assumed that the external force is in a steady state and is not affected by the structure modification, which enables the structure modification for noise reduction without using input identification. The proposed process is applied to a real structure. It is confirmed that the noise level decreases as it was predicted based on the proposed approach.

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Transfer Path Analysis is a key technique for tackling with the noise and vibration problems, and the input identification accuracy influences the result of contribution analysis. The new input identification method (Apparent-Mass Method) was proposed by the authors in the past studies, and the improvement of identification accuracy was shown. However, the random noise included in the both excitation and response signals is inevitable. And these noises induce variation in the identification force due to the fluctuation of estimated apparent-mass matrix and measured operational response. Therefore, the variance evaluation for identified force is important in order to execute more accurate contribution analysis. In this paper, variance estimation methodology for identified force is proposed. Then the validity of proposed method is confirmed using numerical simulation and excitation test.

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We propose a van der Pol-type self-excited cantilever beam by positive velocity feedback and nonlinear feedback. Self-excited oscillation keeps the resonant condition independent of the modulation of system parameters and the resonance characteristic of self-excited oscillation is suitable to realize auto-resonance machines such as AFM micro-cantilever proble. Because the amplitude of self-excited oscillation grows with time, a special control method is required for the amplitude control. To this end, we propose the application of the nonlinear dynamics of van der Pol oscillator. Making use of the characteristic of a stacked-type piezoelectric actuator, we demonstrate that the amplitude control of a cantilever beam by using only integral controller without differential controller. We show the equation of motion in which the nonlinear effect is taken into account and the averaged equation which is derived by applying the method of multiple scales. The bifurcation diagram is theoretically described. Then, it is clarified that the amplitude of the cantilever beam can be controlled by setting the nonlinear feedback gain. Furthermore, a van der Pol-type self-excited cantilever beam is realized by using a simple apparatus and the validity of amplitude control method by integral control is experimentally confirmed.

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Relational expressions to estimate the grip margin of a tire have been derived. By carrying out analysis using isotropic brush model, the grip margin was determined as functions of tire force and aligning torque. We assume quartic ground contact pressure distribution as well as conventional parabolic distribution. Using numerical examples computed by CarSim, a popular vehicle dynamics simulation software, we showed that the results of the quartic distribution gives better conformity with those of the implementation of an experimental nonlinear tire model in CarSim. On the basis of this analysis, the Chebyshev approximation of the solutions that are suitable for real time estimation has been derived.

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This paper tries to identify the individual difference and the proficiency of human operator's behavior from time series data by using fuzzy inference and acquire individual skill of human operator. The operators in the experiemt are skilled to some extent in stabilizing the inverted pendulum by training, and the data of ten trials per person were successively taken for an analysis, where the waveforms of pendulum angle and cart displacement were recorded. The maximum Lyapunov exponents were estimated from experimental time series data against embedding dimensions. The identified fuzzy controller from time series data of each trial of each operator showed well the human-generated decision-making characteristics with the chaos and the large amount of disorder. The estimated degree of freedom of motion increases and the estimated amount of disorder decreases with an increase of proficiency both in fuzzy control simulation and experiment. It also showed that the agreement between the fuzzy control simulation and the experiment for the degree of freedom of motion and the entropy ratio is particularly good when the simulated wave form and the measured wave form resemble in appearance.

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The purpose of this study is to investigate influences of human's mental workloads on a human-mechanical vibration system. The one-degree-of-freedom mechanical structure involving a human body standing on it is considered. The human body and the mechanical structure are modeled as a linear two-degrees-of-freedom coupled vibration system, and the parameters of a human body, such as a mass, a damping coefficient and a stiffness coefficient are identified from the experimental frequency response for the vertical excitation. The cases with two kinds of mental workloads are investigated experimentally, and the relationships between them and the changes of the identified human model's parameters are discussed.

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Passive biped walkers can walk down a shallow slope without actuators. This paper presents a simple planar passive biped walker with flat feet and ankle springs, and investigates the effects of torsional spring stiffness on the pitch motion at the ankle joints. Numerical stability studies indicated that the motion of the passive walker is stable. Physical biped walker has four legs, with each set of two legs connected so that they move identically, to constrain the motion of the walker to the sagittal plane. Experimental results showed that the biped walker can walk stably.

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Injury tolerance has been actively researched as a part of establishing injury criterion of internal organs and application to a simulation model. Mechanical response of the internal organs removed from a cadaver has been often measured by direct compression using a rigid body. However, it is shown that the injury pattern is significantly different between direct impact and indirect impact through soft tissue like muscle and fat. To measure the mechanical response of the liver in the state that load transfer approached in vivo, we conducted an impact test using an abdominal model of a liver surrounded by two groups of muscles, which was removed from a porcine trunk. An impact testing machine utilizing a torsion spring as the energy source and a slider crank mechanism makes it possible to launch an impactor into the abdominal model. Then, deformation volume of only the liver and the hepatic surface pressure were measured using an ultrasonic device and a contact pressure transducer with little influence on the liver behavior. In the result, liver was damaged over 40% maximum compression ratio, and injury scale was proportional to maximum compression ratio. Our experiment shows that the injury pattern in this test was close to that in a traffic accident, and there was high correlation between injury scale and maximum compression ratio.

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