We generalize an idea of the OGY method, which is a well-known, chaos control method, and propose a control method for stabilizing "unstable" trajectories defined on infinite- or finite-time intervals. For this purpose, we use extended concepts of the stable and unstable manifolds of "hyperbolic" trajectories. To demonstrate the effectiveness of the proposed method, we give experimental results for single and coupled pendula.

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The conventional passive dynamic absorber reduces the amplitude of the main system to zero when the natural frequency of the absorber corresponds to the excitation frequency. The dynamic absorber produces two resonance peak. In this paper, we propose the control method of a semi-active dynamic absorber to reduce the amplitude of a sinusoidally excited main system to zero over the wide range of the excitation frequency. The proposed controller estimates the excitation frequency by applying adaptive filter in real time. When the excitation frequency varies, the frequency is estimated in real time and control signal is generated according to the estimated frequency. The stiffness is changed so that the natural frequency of the absorber tracks to the varied excitation frequency. As a result, the response amplitude of the main system is kept to zero over the wide range of excitation frequency. Furthermore, the performance of the proposed control method is experimentally discussed.

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Lateral vibrations of a cantilevered pipe, which is hung vertically with an end mass and conveys fluid, are experimentally and theoretically examined when the flow velocity is constant. We are interested in such a case that two-frequencies oscillation of the pipe involving the two unstable modes at higher flow velocity. This phenomenon will be called mixed/coupled mode flutter.

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A method of vibration analysis in the frequency range of high mode density is proposed. The aim of the method is to reduce the work to analyze modes by grouping many modes into several sets of modes. The grouping is assessed by similarity of the effects of structural modifications, which are made on the noticed portions of the structure. A representative mode is selected among the set of modes and analyzed instead of all modes in the sets. This saves much time for examining many mode shapes and so on. An application to automotive body presents the procedure for the interior noise improvement by modifications of the body structure. This application shows that this method is available for actual problems.

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Transient Statistical Energy Analysis (TSEA) is a useful tool to predict transient vibration and sound responses on structures. In order to predict the transient responses, the estimation of the maximum energy and its rising time on each subsystem are required. In our previous study, we had discussed transient responses of the system with two subsystems by using theoretical approach. It is important to understand shock response by TSEA in case of systems with more than three subsystems.However it is difficult to estimate the maximum energy levels and their times by theoretical way. This paper introduces a method to predict the rising times on more than three subsystems in series by using the modules based on the system with two subsystems.

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The previous paper derived the modal expansion of structural intensity for flexural vibration on a beam. The expansion is expressed by the superposition of modal terms composed of weight functions and cross-modal functions. The weight functions are determined by the natural frequencies and modes and the information of the excitation. The cross-modal function is evaluated by the spatial derivation of the modes. This paper discusses the properties of the cross-modal functions especially by the comparison with the vibration energy in modal space. It is also shown that the distributions of the cross-modal functions can be predicted by the product between the modes. It is useful in the case of the difficulty in evaluating the spatial derivation of the modes.

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This paper derives the relation between a excitation position and a modal expansion of structural intensity of bending vibration on plate. The expansion is expressed by the superposition of modal terms expressed by the product of weight coefficients and cross-modal functions. Weight coefficient is presented by the material properties, excitation condition, and two modes with or without spatial derivatives at excitation point. Cross-modal function is presented by the product of two modes with or without spatial derivatives. Weight coefficients change by a excitation position movement but cross-modal functions not. Numerical simulation is carried out in order to investigate the relation between change of weight coefficients and a excitation position.

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In this paper, the authors present some theoretical discoveries about the relationship among rigid body properties, modal parameters and spatial matrices at first, and then consider the uniqueness and nonuniqueness of solutions in experimental identification from the view point of its practical availability. The theoretical discoveries are of structural dynamics under the free-free boundary condition. That is, "Independence of rigid body properties from elastically deformed natural modes" and "equation of momentum conservation in the form of spatial matrix, natural mode and frequency response function". It is concluded from the consideration of the uniqueness and non-uniqueness of solutions that non-unique solution is available in structural dynamics.

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Modelling the rigid dynamic behaviour of mechanical structures requires knowledge of the structure's mass, centre of gravity location, and moments of inertia. In cases where the geometry or mass distribution is complex, or when no numerical models of these properties exist, the rigid body parameters must be determined experimentally. In this paper, a new experimental method is introduced. The test structure is suspended in soft wires and a mass-spring element is attached successively to at least three different points. For each attachment, the shape and frequency of the seventh vibration mode are determined and used to solve the equations of motion. Our simulation results indicate that the method can achieve high accuracy if the suspension stiffness is low and the natural frequency of the mass-spring element is well chosen.

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Considering on the space development in the future, space scientist should play a key role. There are a lot of researchers taking part in the investigation for space and spreading the study and business chance recently. Space development moves to a project of a private enterprise from a national project. However, the cause why space development did not develop into is to have been able to offer space environment to a researcher with low cost at any time frequently. We will install the several equipments in the satellite. However without passing through the low vibration effect zone at the launching state, our preliminary mission can not be performed. In this paper, we imaged the size of satellite is ten centimeters cube and discuss the optimum structure design regarding to the analysis of the natural frequency. The method of optimum design uses first order method. This method is analysis of the initial design is performed, the results are evaluated against specified design criteria, and the design is modified as necessary. The process is repeated until all specified criteria are met.

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This paper proposes an efficient procedure for finding the possible ranges of uncertain natural frequencies of a finite element model with uncertain parameters. Uncertain model parameters are described by input fuzzy numbers and then output fuzzy numbers are calculated by fuzzy arithmetic. The fuzzy arithmetic used is based on the α-cut concept and interval analysis. To reduce computation time in the interval analysis, the global optimization technique using response surface models is introduced. Furthermore, we propose an approach for finding the feasible ranges of uncertain model parameters when the ranges of natural frequencies are specified. The examples through a simple frame model show that the membership functions of uncertain natural frequencies are efficiently and accurately estimated by the proposed procedure. In addition, the ranges of uncertain model parameters are properly evaluated by the proposed approach.

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This paper deals with a countermeasure against pattern formation phenomena of roll covering-rubber. The pattern formation phenomena sometimes occur in paper making machines, winder systems of elastic yarn and thin sheet winders. In these systems, The pattern formation phenomena are mainly caused by the viscoelastic characteristics of the roll covering rubber, the elastic yarn and the thin sheet. These pattern formation phenomena lead to a fatal damage on products. The authors conducted experiment to clarify the suppressive effect of the damping, the variation of rotating speed and the dynamic absorber on the pattern formation. The authors also theoretically confirmed the countermeasures. The results of the experiments qualitatively coincide with those of the numerical analysis.

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This work deals experimentally with the stability chart of the regenerative chatter vibration in end milling process. By measuring the vibration of the tool directly in cutting with two laser displacement sensors, it is shown that the vibration characteristics of chatter near the cutting point is evaluated and the stability limits of chatter are able to be derived more definitely. In this work, the stability limit was determined by evaluating chatter frequency and the phase angles between present vibrations and the vibration in the previous cutting process. Finally, it was shown that the relationship between stability chart, chatter frequencies, and phase angle in various spindle speed.

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This paper deals with analytical results of stability on the polygonal deformation phenomena in BTA deep hole drilling. The authors made an experimental equipment and proposed model for it, then performed numerical analysis. According to the results of the analysis with or without guides, stability of system on the polygonal deformation phenomena and effects of guides on it are confirmed.

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The major occurrence mechanism of pattern formation phenomena has been considered unstable vibrations generated in linear time delay systems. A stabilization of the system using a dynamic absorber was proposed as one of prevention methods, and the validity was confirmed from numerical analysis. In this report, an experimental setup of the viscoelastic system was fabricated in order to verify the validity of dynamic absorber and its design method using a new stability analysis method developed by the authors. The results for single-degree-of-freedom system indicate that the prevention method using a dynamic absorber is effective for the pattern formation phenomena.

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Pattern formation phenomena often occur in contact rotating systems. A prevention method by using dynamic absorbers was suggested and an optimal design method of the dynamic absorbers was formulated in the previous reports. However, much computation time is required to establish the optimal parameters for multi-degree-of-freedom systems since design variables increase. The authors suggest an efficient design method of dynamic absorbers, in which the dynamic absorbers are individually designed one by one for each mode. The effectiveness of the present method is verified from the results of numerical computations for a five-degree-of-freedom system as an example.

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This paper describes realization of mutual entrainment simulating synchronous flashing of fireflies. To simulate synchronous flashing of fireflies, we invented self-excited oscillator consists phase delay element, amplification element and saturation element. For a general design of self-excited oscillator, we made the characteristic between the input and the output to self-excited oscillator linear transfer function. We developed the technique for requesting a synchronous area and the phase difference that is a synchronous characteristic by using a linear transfer function. We produced an electronic firefly with the electric circuit and reproduced the phenomenon similar to synchronous flashing of fireflies.

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The goal of this study is to realize the motion control of multi-degrees-of-freedom system by the distributed control utilizing an entrainment. We examined forced and mutual entrainment by a basic element which is two mass self-excited oscillator connected by a spring. In the mutual entrainment, when two elements are connected by a spring and a damper, two types of entrainments were generated. Firstly, one element is a oscillating action and another one is a damping action. Secondly, both elements are oscillating actions. Moreover, we investigated the mutual entrainment in the case that two elements are connected almost rigidly.

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In the present study, acoustic wave propagation in an enclosure surrounded by fractal walls is simulated and studied using Cellular Automata (CA). CA is a discrete system which consists of finite state variables, arranged on a uniform grid (cell). CA dynamics is described by a local interaction rule, which is used for computation of new state of each cell from the present state at every time step. In this paper, the influence of fractal shaped boundary structure on resonance and sound absorption characteristics is investigated for two dimensional acoustic wave propagation model using CA. Local rules are provided for construction of fractal patterns as well as representation of wave propagation phenomena. Direct numerical simulations are performed and resonance characteristics are obtained for evaluating fractal level influence on sound attenuation.

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In the present study, acoustic wave propagation in the field including sound isolation panel is simulated using Cellular Automata(CA). CA is a discrete system which consists of finite state variables, arranged on a uniform grid (cell). CA dynamics is described by a local interaction rule, which is used for computation of new state of each cells from the present state at every time step. In this study a sound field model is characterized by direct modeling of the shape of sound isolation panel and sound source frequency. Direct numerical simulation is performed using CA model and evaluated by insertion loss or sound pressure. The results showed good correspondence with analytical solutions.

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This paper deals with nonlinear liquid surface and interfacial wave motions in a tank containing two incompressible irrotational fluids of different densities. In theoretical analysis, the time histories and the transitions of surface and interfacial wave motions in a rectangular tank are given by solving the canonical equation of this system. Moreover, we discussed occurance conditions of N-wave interactions by investigating the properties of natural frequencies. On the other hand, The validly of the theoretical analysis is verified through the experiments. These results are in good agreement with each other.

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This study describes a nonlinear vibration behavior of a cylindrical water storage tank under large excitation and the numerical simulation by finite element method. When the tank is excited largely, its maximum response does not grow in proportion to the input. It is found that this phenomenon is caused by the coupling between the beam-type vibration and the oval-type vibration. The dynamic and large deformation analysis considering the coupling between fluid and structure is performed by the finite element method in order to simulate this phenomenon. The analytical results agree with the experimental results very well.

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This paper deals with an active feedback control of sloshing in a liquid transport container by using a moving baffle plate. By inserting the moving baffle plate into the container vertically, the sloshing is effectively suppressed by the energy dissipation caused by vortexes generated around the edge of the moving baffle plate. In this paper, suppression effect by the moving baffle plate on residual sloshing excited by periodic excitation or by sudden stop of the transport container is examined experimentally. The control performance is clarified by changing the controller gain and phase shift, and suppression mechanism is discussed by visualized flow patterns of the fluid flow.

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The effect of simple spiral fin around a bare tube on Karman vortex shedding was experimentally investigated. We measured the distributions of mean velocity, the intensity of velocity fluctuation, the spectrum of velocity fluctuation and the coherence distribution of Karman vortex in the spanwise direction. And the flow around a fin tube was visualized by using smoke wire technique. As a result it was made clear that Karman vortex in the near-wake of the fin tube make the cell structure with the scale of pitch length of the fins. The large scale vortex was formed by the reconnection of the vortex cells.

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When elastic objects are located in the flow region, unstable vibrations occur due to coupling between motions of the objects and the flow region. This report treats the unstable whirling of an elastic bar that is located close to a circular cylinder in the flow region. Fundamental characteristics that include the whirling directions and the influence of some parameters are examined experimentally. Experimental results clarify that the whirling direction of the elastic bar depends on the positional relationship between the bar and the cylinder. In addition, the results are compared with the analytical results of the previous report that treats the unstable vibration of braces that are adjacent to a high circular stack.

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In order to study aerodynamic characteristics of an access arm equipped on hard disk drives, we proposed a new method of simulating high-speed air flow around an access arm by water flow with an enlarged arm model based on Reynolds number similitude. Flow visualization around the arm model and measurement of fluid dynamic force were conducted. In the experiments, a shear flow generator of honeycomb type was used to simulate velocity profile of flow between corotating disks. As a result, it was found that incidence profile has little effect on the dynamic lift of an access arm

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There are several formulations for beam element in the large deformation and displacement problem. Recently, the absolute nodal coordinate formulations are studied for such problems. In this paper, the authors propose an assembling method of the beam element for which the shape function is expressed in terms of the quadratic function in the absolute nodal coordinate approach. The usefulness of the proposed method is verified by the numerical simulations.

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This paper describes the evaluation of real-time performance and computation time of the multibody dynamic analysis with natural coordinates. The real-time performance was evaluated with the model of multiple pendulums. The multibody dynamic analysis with natural coordinates were compared with reference point coordinates in computation time and real-time performance. Calculation result shows that the computation time of multibody dynamic analysis with natural coordinates were faster than that of the reference point coordinates on the multiple pendulums, and the real-time performance of natural coordinates is more effective than that of reference point coordinates.

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This study considers the optimal control problem of link systems. The goal of this study is to develop a general optimal control algorithm that can find the solution by inputting only kinematical and dynamical parameters. In the previous report, a general optimal control algorithm for open link systems is suggested as a first step. In this paper, the algorithm is extended as it can be applied to tree-structure link systems. The validity of the method is confirmed by applying it to the problem of a 2D space robot with 2 arms.

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This study considers the problem to develop a general optimal control algorithm for link systems. In the previous report, a general optimal control algorithm for open link systems is suggested as a first step. In this paper, the algorithm is extended as it can be applied to closed link systems. An optimal control problem of a simple closed-link robot is solved to demonstrate the effectiveness of the proposed algorithm.

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Tire forces are greatly affected by suspension characteristics. Thus, suspension characteristics are very important for vehicle dynamics. In this paper, to evaluate the effects of tire-suspension system on vehicle dynamics, we developed a tire-suspension hardware-in-the-loop (HIL) simulator with an original testing machine that consists of a tire, a suspension system of passenger car and 6-degerr-of-freedom (6-DOF) motion platform. In this HIL simulator, real-time vehicle dynamic analysis is executed with measured tire forces, and 6-DOF motion platform is controlled based on analytical results. The effectivity of tire-suspension HIL simulator was examined by evaluation test.

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At our previous study we tried applying Neural network with the simulation result of straight brake motion and vehicle turning motion as teaching data to perform traffic accident reconstruction simulation. Recently vehicle with safety devices such as ABS or ESC(Electronic Stability Control) is spreading. In this study we perform inverse analysis of vehicle motion for straight braking and vehicle turning motion for vehicle with ABS. The tire damage takes about 30% of trouble at highway. Especially tire-burst easily causes a serious accident. So we perform reconstruction of vehicle motion with tire-burst, as one example of inverse analysis of motion of vehicle with trouble.

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The decrease of wheel load variation is one of the most important issues which must be solved in railway dynamics. The purpose of this study is to make clear the mechanism of wheel load variation by the numerical simulation by the analytical model which is based on the concept of the multibody dynamics. In this study, we were able to figure out the in-depth mechanism of the wheel load variation, particularly, concerning the phenomenon that the wheel load variation suddenly decreases with more than wheel velocity at which the 1^<st> natural frequency of system consists with the irregularity passing frequency.

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The natural vibration modes similar to the gait patterns of quadrupedal walking exist in the rigid body link model which is modeled after quadrupedal frame system. We focused our efforts on the scapular and the pelvic motions of quadruped animal. Then, we investigated the relation between their motion and the natural vibration modes of quadrupedal frame system, using the rigid body link model. In addition, we showed that the natural frequency of the rigid body link model was close to quadrupedal walking frequency in the case that the physical characteristics of a horse were given to the rigid body link model.

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A numerical analysis was attempt to clarify the piston slap phenomenon considering the effects of lubricating oil-film and the piston deformation. Oil-film is formed in the clearance between piston skirt and cylinder liner in the operating engine. The oil-film pressure was obtained by solving the Reynolds equation with the aid of numerical analysis of two dimensional piston movements. The piston skirt deformation was also calculated through FEM considering the oil-film pressure. Then the distribution of oil-film pressure on the piston skirt surface was discussed in the relation of piston movement and deformation.

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To analyze the operational stress of engine main bearings, we developed a new component mode synthesis method which was useful for the flexible multibody dynamics (FMBD) analysis of the crankshaftcylinderblock system including large(million-size) FE models. The new method can consider both the entire deformation modes of cylinderblock and local deformation modes of the main bearings by several hundreds modes. It was applied to FMBD analysis of an in-line 4 cylinder engine under runnning conditions. As the experimental verification results, we verified that the proposal methods was more accurate and effective to analyze the strain of the engine main bearings.

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In this investigation, a modeling procedure for a tire with flexible belt is developed. The elastic deformation of the belt is modeled using the finite element absolute nodal coordinate formulation which allows for describing large rotational motion and the nonlinear inertia effects; the curved structure of the flexible belt; and moving boundary resulting from tread/road interaction. Using a concept of elastic ring tire models, the sidewall flexibility of tires is modeled using circumferential/radial springs and dampers between the belt and rim, while the tangential tread/road contact force is modeled using friction elements defined at contact nodes within the curved belt elements. Numerical examples are presented in order to demonstrate the use of the flexible tire model developed in this investigation. Good agreements in the tire vibration characteristics obtained using the experiments and the proposed model are demonstrated. It is also shown that the proposed tire model can be used for assessing dynamic characteristics of tires in high frequency ranges resulting from the interaction to uneven roads.

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A link model the fishing rod, the line and the weight are used in order to determine the Multibody Dynamics to be considered a geometrical nonlinearity of a large deformation. A throwing simulation is analyzed using the link model in the calculation of casting air drag and frictional resistance given by guides and reel. High speed camera pictures are taken of advanced and beginner angler's castings, the numerical data of throwing-in is used in the simulation. The optimal stiffness, distribution of stiffness and weight of the fishing rod with which the flying distance of the sinker becomes maximum for both advanced and beginner, are investigated.

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This paper deals with strength design and dynamic analysis of a machine structure by 3D Computer Aided Design (3DCAD) and Computer Aided Engineering (CAE). The worm gear speed reducer for research might cause oil leak, in the case of the use of large load fluctuation. The purpose of this research is to consider the cause and proposed measures of the oil leak. As one of the causes, it is thought that the thrust power of a worm causes the oil leak. So, in this experiment, displacement of bearing cover by the thrust power of a worm is measured. The validity of analysis is shown by comparison of experimental result and analysis result. The bearing cover that reduces displacement is calculated by 3DCAD and CAE.

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In the present work, relationship between probability of piping failure and loss of function in the system, and risk by piping failure are evaluated for the system of plural pipes in nuclear power plants. Appling these risk-informed, the calculation model and the code to minimize amount of total piping weight (piping cost) is developed by performing suitable thickness distribution of every piping under the condition of equivalent or lower than the present risk. Validity and applicability of the code are investigated.

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This paper presents a topology optimization method of framework structures using the genetic algorithm and the generalized transfer stiffness coefficient method (GTSCM). The two-objective optimization problem that minimizes the total weight and maximizes the first natural frequency under the displacement constraint and the stress constraint is formulated, and the genetic algorithm based on the ground structure approach is developed. In the present algorithm, the merits of the GTSCM are utilized in order to improve the computation efficiently, and the effective methods of genetic operations for the topology optimization problem are proposed.

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In this paper we review recent trends in optimization methods, which have been using vehicle body design. Especially we discuss about multi-objective optimization methods and robust design methods in detail, and show some application examples, such like crashworthiness, occupant safety and so on.

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In recent years, A. Ganek proposes general concepts of the Autonomic Computing for reducing total cost of ownership, improving quality of services, accelerating time to value and managing IT complexity. The autonomic computing introduces four characteristics: self-configuring, self-healing, self-optimizing and self-protecting. Authors propose to introduce the self-optimizing for optimal design problems with uncertainty. The proposed method is applied to a control problem of Harmonic Drive System to check the performance of convergence, and the validity of the proposed method is discussed.

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Authors had been developed the optimal control theory based on energy equation, and clarified that this method is useful to design controllers for energy regenerative control systems. This paper deals with the control problems of erectro-hydraulic type activesuspension. Especially, extension for energy regenerative control systems. This paper deals with the control problems of erectro-hydraulic type activesuspension. Especially, extension obtained as follows. 1)The extension of the criteria function based on energy flow induced superior control law. 2)In this method, road profile information is not so important and it can abbreviate. 3) Erectro-hydraulic type actuator is suitable to realize energy regenerative activesuspension.

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The ICP (Iterative Closest Point) algorithm is widely used for geometricalignment of three-dimensional models when an initial estimate of the relative pose is known. The first step of the ICP algorithm is to select a few points from point clouds which is to be registrated. As a typical type of iterative algorithm, however, the less number of selected points, the rougher accuracy will be, though computational speed will higher. To balance both the computational speed and the accuracy seems to be difficult. In order to solve this problem, in this paper, we describe a method of registration based on extracting features directly from surface point clouds, that will not only improve the computation speed but also ensure the accuracy.

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In these days finite element method is often used to design and develop products effectively. Using it engineers can evaluate the impacts of design changes without any experiments, so the method which can analyze dynamic characteristics of the much changed structure rapidly is required. Yamazaki and Hagiwara developed the new perturbation method with complementary term for this purpose and showed the possibility to reduce the analysis time drastically, but this method causes the extreme slowing down and instability problems when the structure changed widely. Here, we propose the new complementary vector compute method and the way to calcurate responses effectively to solve these problems, and evaluate the accuracy, calculation speed and stability of these methods.

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The purpose of this study is to analyze the relation between the voice articulation and the reproduced sound characteristics by piezoelectric speaker. In this paper, the piezoelectric speaker and the dynamic speaker are compared. In order to clarify the correlation, the characteristics of consonant articulation in the car interior under car cruising noise is evaluated. The experimental results show that the consonant articulation is increased when the rising spectrogram of reproduced sound is similar to the source signal spectrogram. And, the piezoelectric speaker well reproduced the consonant voice which include the high frequency in rising spectrogram.

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Sound of guitar is affected greatly by amplitude and damping of harmonics of fundamental frequency of string. In this study, we develop mathematical model of body and strings which have tension and carry out eigenvalue analysis and frequency response using ANSYS 11.0. We examine change of frequency response and bsound quality by changing material characteristics of the body. From the calculation results by ANSYS, it can be seen frequency response changes significantly by changing material characteristics

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In the research of the tone quality of a classic guitar, the measurement of the mode of vibration of the surface board is important. It is necessary to measure various guitars chosen by the musician, and to evaluate the comparison between tone quality and the vibration characteristic in the accumulation senses. Because surface boards of valuable musical instruments are damaged, the hammering cannot be done. Moreover, a lot of measurement points are necessary to measure the mode of vibration to the high frequency region. It proposes the method of measuring the adjacent sound of the surface board the multipoint simultaneously.

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Front soundboard of classical guitar is the most important as part giving a sound. Because, it emit many sound energy. And, sound board has braces to reinforce it. We examined a difference of bracing pattern by investigating a vibration characteristic and an acoustic feature.

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