In the research of the tone quality of a classic guitar, the control of the vibration modes on the surface board is important. It is necessary to combine the traditional trial and error approach with the engineering approach. Here are the some kinds of studies for stiffening rib layout on the sound board of the guitar. We need to get the impact volume of the guitar sound for the lower frequency zone and the rich quality of the sound for the higher frequency zone. We give the suitable distribution of stiffening rib layout density for the optimization of the guitar sound.

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Humans are able to well recognize mixtures of speech signals produced by two or more simultaneous speakers. This ability is known as cocktail party effect. Applying the cocktail party effect to engineering, we can construct novel systems of blind source separation such as current automatic speech recognition systems and active noise control systems under environment noises. Considering blind source separation as the characteristics of human, artificial neural networks are suitable for it. In this paper, we proposed a method of blind source separation using a neural network. The present neural network can adaptively separate sound sources on training the internal parameters.

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The purpose of this study is to analyze the relation between the syllable articulation and the sound characteristics of the reproduced sound by various speakers under car interior noise. The syllable articulation of piezoelectric speakers and dynamic speakers were compared. These articulation evaluations were carried out in an actual automobile. Results showed that the consonant articulation of the reproduction sound that the consonant is loud, and the frequency characteristics is near the input signal is higher than each speaker. It was found that long sustained consonants with rich high frequency content showed high articulation in car interior noise.

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This paper considers the active control method to reduce harmonic sound transmission through a double-leaf partition radiated from a vibration symmetric structure into a free field using error signals derived from structural sensing. The double-leaf partition consists of a pair of small plates separated by a air gap. It has been found that taking advantage of the symmetric properties of structural modal functions, "radiation cluster", which is an orthogonal contributor with respect to acoustic fields, can be defined. The philosophy of radiation cluster control by active means will be applied to a double-leaf partition.

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Non-contact control technology utilizing acoustic radiation pressure (ARP) has been researched in various fields. This research deals with non-contact vibration control utilizing ARP. According to previous researches, the basic characteristics of ARP had been clarified. In this paper, the vibration damping effect by ARP is investigated. A simple pendulum is located between two vibrators facing each other and is subjected to ARP generated by them. Changing the gap distance between vibration surfaces and the pendulum, the pendulum possesses damped or unstable vibration due to ARP characteristics. Moreover, active vibration control by modulating oscillating current for vibrations is also applied by using feed back control law. The presented feed back control system showed good damping effect. These control characteristics are also investigated infrequency domain by using a pendulum subjected to forced oscillation.

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To meet the shortening development time in automotive development, simulations are used as design validation, i.e. the prediction of tail pipe noise and radiation noise is needed for design validation of muffler. Although authors are simulating the tail pipe noise on development, radiation noise simulation is harder work than tail pipe noise one. The reason is following. In case of tail pipe noise, by calculating internal flow in an exhaust system and then getting a gas velocity at opening of a tail pipe, the sound pressure level at any point in the atmosphere can be easily obtained. In case of radiation noise, however, first the pulsation in exhaust pipe excites its structure. Next the vibration of structure excites air around structure, and then noises are radiated. Consequently, to obtain an accurate result of radiation noise which can be used for design validation, the calculation of fluid flow, vibration of structure, and sound must be done accurately. The simulation technique that can be used for design validation was achieved through conforming experimental results by authors.

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I have been proposing the converted Nearfield Acoustic Holography (NAH), the NAH with extra spatial spectrums. This method can overcome the sampling limitation of NAH, and realize the quick measurement in high frequency. In this research, the application of converted NAH to the noise measurement of the general electric products is reported. As a result, the converted NAH method has better resolution than original NAH in same measurement settings, but less resolution than well measured original NAH which takes quite long measurement time. Therefore the proposing method can be used as a abbreviated method of original NAH.

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This research investigates ultrasonic detection of nonlinear vibration caused by collisions between two faces of a closed crack under incidence of ultrasonic waves. Theoretical analysis has been developed, using a one-dimensional elastic body model hit at its end by a sinusoidally excited base. Qualitative changes in elastic waves detected at its other end occur and lower-order eigenfrequencies can appear, depending on the input frequency of the base. Experiments have also been carried out, using a model of two solid blocks in contact. Experimental results are similar to the theoretical results above.

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Inspection by using guided waves has been studied for a purpose of non-destructive testing. Though guided waves decay greatly due to stressed boundary conditions, most of the researches on it use the stress-free boundary condition as the idealized boundary conditions. In this research, we evaluated effects of the structure under different boundary conditions(the stress-free boundary condition and the displacement-free boundary condition) on the propagation of Lamb's wave (guided waves propagating in an elastic plate) with numerical analysis using finite element method.

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Increasing interest in environmental matters, a quiet motor are drastically demanded lately. Among of acoustic noise of the motor, electromagnetic acoustic noise is jarring and is studied recently. Electromagnetic acoustic noise is strongly affected by (1) increase of magnetic density by reduction of motor size and (2) decrease of stiffness by right weight. In order to reduce electromagnetic acoustic noise, it is necessary to design the motor, of which natural frequencies of does not coincide with electromagnetic force frequencies. In order to avoid the resonance of the natural frequencies of the core and the electromagnetic force frequencies at designing phase, machine designer has to accurately predict these frequencies. In order to reduce the electromagnetic acoustic noise, this paper studies the following things, which are not clarified in previous research. Simulation method of the natural frequency in laminated steel sheet stator core

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In this report, the influence that the mode shape of the vibration energy flow gave to the distribution of the transfer power is discussed by the numerical simulation. The transfer power is calculated by using the structural intensity in a plain plate, and the transfer power is compared with the vibration energy flow and the natural mode. As the results, the direction and value of the transfer power is decided at the composition rate of the weight coefficient of the natural mode.

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Estimation of instantaneous damping and frequencies by the wavelet transform is based on the ridge identification and the phase extraction in the time-frequency map. Time-varying parameters due to nonlinearities are also estimated by this technique. However, the process of the ridge identification is complicated, and the most suitable mother wavelet to yield a time-frequency map for an efficient identification can not be determinately chosen. There are some problems in easiness to operate the technique. In this paper, The time-varying parameters pertaining to nonlinearities are successfully estimated by the segmental harmonic wavelet transform. It is possible to identify parameters pertaining to nonlinearities qualitatively and quantitatively by the segmental harmonic wavelet transform.

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In general, agricultural tire has high and large cross-switch lugs to keep moving performance without slip in rice fields. Therefore the vibration and the noise caused by the interaction between the tire lugs and the road surface are inevitable when the agricultural machinery runs on-road. In this study, the test equipment is manufactured to measure the motion of the rolling agricultual tire with ground contact. The test equipment is modeled as mass-damper-spring system and the dynamic characteristics of the tire are identified from the experimentally measured data by using the method of least squares. As a result, the influence of rotational velocity on the dynamic characteristics are investigated.

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A technique for countermeasures against structure-borne sound in pomp piping system is newly proposed. The technique using two joints that was developed in our previous work has the practical difficulty that the pipe's vibration mode must be measured many times in order to determine the optimum location of joints. In the new technique, after two joints are installed in the arbitrary location, a rigid disk is mounted on the upstream of piping. The pipe vibration can be easily reduced by just adjusting the location of the disk. In this paper, the influence of underwater sound is neglected and the effectiveness of the new technique in reducing vibration in straight-line piping is investigated experimentally and analytically.

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When we take pictures with continuous shots with single lens reflex camera, the inner mirror must repeats to go down and up with very high-speed. In this operation, the mirror hits to a stopper and rebound instantaneously. We investigate the rebound characteristics of the mirror model with free fall testing. Rebound angle of the model is varying by the stopper position. In the experiments, we find the stopper position which has lower amount of rebound angle. And the experimental modal analysis is carried out for the mirror and stopper model. It is found that the modal dumping ratio is correlate with the amount of rebound angle.

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We used an external vibration to move an elastic body. This research aims to analyze the moving behavior of an elastic body for excitation amplitude and excitation frequency of plate excided externally by the experiment and the numerical simulation, and to clarify the mechanism of the moving behavior. As a result, it was clarified that its horizontal displacement and, the moving behavior changed to be forward, to be backward or to repeat to be forward and to be backward in a short time according to the timing when its both legs contacted with the plate.

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When the upper end of a point-mass pendulum that is inclined from vertical is moved up and down, the point mass is conveyed forward. This up-and-down motion can be regarded as the fundamental casting motion for conveyance of an object. This paper treats the casting system consisting of a rigid rod and a point-mass pendulum. The rod can rotate arbitrary around a fixed point by an actuator, and the pendulum is attached to the tip of the rod. Relationship between the rod motion and the conveyance condition of the mass is investigated numerically using the shooting method.

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This paper proposes a new method for the trajectory planning of a two-link rigid-flexible manipulator in a point-to-point motion. In order to obtain a mathematical model properly, the flexible link is modeled by considering the axial displacement and the nonlinear curvature due to large bending deformation. The Lagrangian approach in conjunction with the assumed modes method is applied to derive the equations of motion of the manipulator. In the trajectory planning, we express the desired joint angle of the flexible link by a cubic spline function, and then use a particle swarm optimization to minimize the joint driving torque. We show that the residual vibrations of the flexible link can be suppressed as a result of the minimum driving torque requirement. In the numerical calculation, we verify the effectiveness of the proposed trajectory planning.

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To suppress the residual vibration of overhead traveling crane in positioning, the construction methods of driving force pattern are proposed. The crane system is considered 2-DOF system consists of a trolley and a simple pendulum, and the natural period is determined. Based on this period, force patterns are designed in a similar way to the vibration suppressing acceleration input patterns that the authors proposed. By numerical simulation it is clarified that the pattern can be adapted to the driving force as well as acceleration input. The Coulomb friction between the trolley and its rail is also considered.

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The construction methods of acceleration input pattern which suppress the residual vibration in positioning of a jib crane are proposed. In derricking motion, the moment acting on the payload due to inertia force is nonlinear function of the derricking angle. So the effectiveness of the proposed methods is not clear. However, by numerical simulation, it is clarified that the combination of proposed methods can suppress the residual vibration instead of nonlinearity of the moment. By window function method, the robustness is also achieved.

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In this paper, we describe the coupled vibration of oscillators mounted on a plate hanging on four strings and investigate the effects of damping on such vibration. From the experimental and numerical simulation results, the following result was obtained. There is an area of parameters, which produce the small amplitude of the support vibration.

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Gear rattle of multi-step helical gear system is treated. Mesh stiffness variations are considered in the system. The effects of the mesh stiffness variations and the ratio of static torque to dynamic one on the rattle are studied by numerical analysis. As a result, the followings were made clear. (1) Because of interaction of dynamic torque and mesh stiffness variation, resonances like gear noise occur in low frequency region, and the number of them is equals to that of natural frequencies. (2) In the gear rattles of this type and other type which generates because of small constant torque in extremely low frequency, the rattle of 1st-stage is dominant and that of 2nd-stage is generated by the 1st-stage rattle. (3) Nonlinear phenomena like chaos and higher harmonic resonance occur as in single-stage gear system.

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Experimental results are presented on chaotic vibrations of a circular plate with initial deformation. The plate is excited by lateral periodic excitation In typical frequency range, non-periodic response is observed. The response shows the irregular amplitude modulation. The response is examined by the Fourier spectra and the maximum Lyapunov exponent. The response is generated from internal resonance condition of one to four and the response is determined as the chaos. Multiple time responses of the plate are measured simultaneously. The principal components are calculated by the Karhunen-Loeve transformation. The three lower modes of vibration are generated in the chaos. The lowest mode of vibration contributes to the chaos dominantly. While, the second mode with one nodal diameter and the third mode with two nodal diameters contribute with small amount. However, the principal component with short time interval show that the third mode is generated in the large amplitude of response, while, the second mode prevail in the small amplitude of response.

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Experimental results are presented on chaotic vibrations of a rectangular plate with an in-plane elastic constraint. Opposite edges of the plate are clamped and the other edges are simply supported. One side of the clamped edges is connected with elastic springs and is movable to an in-plane direction. Under the selected in-plane compressive force, the plate has the conditions of internal resonances. By exciting the plate with periodic lateral acceleration, chaotic responses are obtained in specific frequency regions of excitation. The chaotic responses are examined with the Fourier spectra, the principal components analysis and the maximum Lyapunov exponents. It is found that the chaotic responses are generated with the condition of the internal resonances of multiple modes. In the dominant chaotic responses, the ultra-sub-harmonic resonance of 2/3 order with the first mode of vibration and the ultra-sub-harmonic resonance of 4/3 order with the second mode of vibration contribute to the chaotic response. By changing exiting amplitude, instability boundaries of the chaotic responses are also clarified.

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In this paper, we investigate the primary resonances of nonlinear dynamics of a horizontally supported Jeffcot rotor with relatively large umblance. The nonlinear normal modes are investigated from the averaged equation.natural frequency of the frequency. Because the linear stiffness in the horizontal and vertical directions is slightly difference due to the gravity, the backbone curve is much more complexted than the vertically supported rotor and bifurcation of the backbone cureve produces modes whose number is greater than the degrees-of-freedom.. We theoretically clarify the relationship between the frequency response curve of the horizontally supported rotor in the primary resonance and the backbone curves. Furthermore, we experimentally confirm the existence of the complex frequency response curve which is related to the nonlinear normal nodes.

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In order to reduce the vibration of helicopters, the pendulum absorbers are often adopted. But, most of the papers analyzed its characteristics based on the linear theory and explained focusing on the anti-resonance point. Since the pendulum may vibrate with large amplitude, it is expected that the non-linearity have essential influence on its vibration characteristics. Therefore, we investigated the vibration suppression of the pendulum absorber considering its nonlinearity. In our first report, we proposed a 2-degree-of-freedom (2DOF) model composed of a rigid rotor blade and the pendulum absorber. The blade is excited by giving a sinusoidal deflection at its end. In the second report, we proposed a 3DOF by adding the fuselage. In both of these papers, the blade is considered rigid. The blade is excited by a sinusoidal distributed force. In this paper, a 3DOF model which is composed of a mass corresponding to a rotor mount on the fuselage, a flexible blade, and a pendulum. A periodic distributed force is given on the blade. We show that the vibration is well-suppressed by the pendulum absorbers.

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This paper treats the vibration surpression by piezoelectric shunt damping. Use of a piezoelectric element to which a shunt circuit composed of a resistor and an inductor are connected is one of the efficient techniques of vibration control. Recently, to improve the performance of the shunt damping, switching of the shunt circuit was attempted. In previous works, one of the authors found in the study of elastic impact dampers that the switch of the dynamic characteristics of the damper gives good perfomance for vibration surpression in some condisions. In this paper, the possibility of improvement of vibration surpression by switching the dynamic characteristics in the shunt circuits is discussed based on the results of numerical simulation.

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The purpose of this research is to develop a vibrating tool utilizing self-synchronized phenomena in order to reduce the hand-transmitted vibration. In the present study, the validity of the coupled oscillators (Model 2) that was developed in our previous reports is investigated experimentally and analytically. The results confirmed that the vibration pattern which can realize utilization of vibration and vibration control at once is generated in Model 2. In addition, the coupled oscillators (Model 3) with consideration of rotational degree of freedom is newly developed and the availableness of the synchronized pattern generated in Model 3 is examined.

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In the torsional vibration of a small vessel driveshaft system, ripple torque from engine excites the first mode vibration and causes rattle noise from the final gear. Employing soft shaft coupling may suppress this noise. However, this makes second mode resonant frequency lower and resonates driveshaft system in the nominal rotational speed range. In this study, hardening shaft coupling using permanent magnet is proposed. This coupling works as softer spring in idle rotation range and harder spring in nominal drive range by static torque, and this characteristic help avoidance of resonance. To verify dynamic characteristics of this hardening spring, scale model experiment was conducted, and compared numerical simulation with experiment. The analytical results agree well with the experimental results.

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A rational reduction method using modal analysis is developed in order to analyze accurately a large-scale nonlinear system. Nodes without nonlinear excitation are transformed into the modal coordinates, and the modes with significant effect on computation accuracy of the vibration analysis are extracted. On the other hands, the remaining modes with small effect are appropriately approximated and are eliminated. The very accurate low-dimensional model is constructed by these procedures. The effectiveness of this method is verified from the computational results.

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In this report, a rational reduction method for a large-scale nonlinear system using constrained modes is presented. Generally, analysis methods based on linear modal expansion, which are usually called Galerkin's method, are used in vibration analysis of large-scale nonlinear systems. Then, analysis methods based on this method have good point that regularity and versatility of algorithm are highly sophisticated, but also have bad point that accuracy of analysis deteriorate significantly if adopted modes were not adequate for constituting a reduction model. Still more, practical calculation often becomes impossible because computation time increases explosively with increasing the number of adopting modes to improve the computational accuracy. To overcome these problems, authors proposed a rational reduction method using constrained modes for a large-scale system having locally nonlinear elements. In this report, by applying the harmonic balance method to a reduction model, a method for obtaining periodic steady-state solution is presented.

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Various resonances in an axially moving band are produced by the wheel eccentricities and band imperfection. In this research, we focus on the nonlinear resonances for the first mode of the band span under various rotation speeds of the wheel. The resonance occurs in the case when rotational period of the wheel is an integer multiple of natural period of the band. Also, we propose a stabilization method by using a nonlinear coupling between the belt and absorber whose natural frequency is twice that of the first mode of the belt.

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A coupled inverted pendula model of competition and cooperation is proposed to develop a purely mechanical implementation comparable to the Lotka-Volterra competition model. It is numerically shown that our model can produce the four stable equilibriums analogous to ecological coexistence, dominance, and scramble. Moreover, fractal structures arises in basins of attractions to the equilibriums. This implies that in experimental situations, it will be uncertain which equilibrium is produced by a given initial position under limited mechanical precisions.

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In this paper wiping motion of the wiper blade is studied. First, the experiment was conducted with actual wiper systems to observe the phenomena during the wiping motion including reversal behavior. Second, the multi-degree-of-freedom spring-mass analytical model, which essentially characterizes the wiper systems, was developed from the observation. Then, the equations governing the wiping motion including the reversal behavior of the wiper system were derived from the viewpoints of the multibody dynamics. Finally the dimensionless governing equations were solved numerically and discussed about it.

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Analytical results are presented on nonlinear vibrations of a cantilevered beam with initial deflection elastically constrained by stretched string at the beam end. The beam is subjected to periodic lateral acceleration. Nonlinear responses are obtained by the harmonic balance method and by the numerical integration. Results of analysis show that the chaotic responses are generated in the frequency region near the lowest natural frequency. The frequency regions of chaos are narrowed by the increase of initial deflection. The number of modes generated in the chaos is counted as two by the Lyapunov dimension. The principal component analysis shows the predominant contribution of the lowest mode of vibration.

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Experimental results are presented on chaotic vibrations of a post-buckled cantilevered beam connected to a spring-mass system by a string. The string is stretched between the beam end and leaf springs of spring-mass system on a base. Applying tensile force to the string, the beam is compressed, and then the beam is buckled to a post-buckled state. The axial force and the shearing force of the beam are varied due to the geometrical configuration of deflection of the beam and the displacement of the leaf spring. The beam is subjected to lateral periodic acceleration, chaotic responses are observed in typical frequency region. Predominant chaotic responses are examined by the Fourier spectrum, the Poincare map and the maximum Lyapnov exponents. Contributions of vibration modes to the chaotic responses are analyzed by the principal component analysis. Increasing the amount of the mass in the spring-mass system, the maximum Lyapnov exponents and the corresponding embedding dimension increase. The figure of the Poincare map looses the focus due to the increase of the maximum Lyapnov exponents.

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Authors propose a cluster control type magnetrheological (MR) fluid damper. The damper consists of a sealed MR fluid tank and magnetic circuit. The MR fluid tank set between poles of the magnetic circuit. MR fluid clusters are formed by magnetic field applied by the magnetic circuit. When the MR fluid tank sliding, the MR fluids clusters still exist near the poles of the magnetic circuit. Carrier liquid through between the clusters provides viscous resistance to the motion. In this study, the cluster control MR fluid dumper using wedged magnetic poles and thin MR fluid (3vol%) shows capability of working as viscus damper.

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This paper investigates a possibility of the self-identification of adaptive structure systems using multiple variable structural parameters. A variable inertia and a variable stiffness systems are used to increase the amount of the vibration data that can be used for the identification of the unknown bending stiffness and mass property of the cantilevered beam. The experimental demonstrations are presented to show the feasibility of the proposed method. It is shown that the identifiability of the unknown parameters under the ill-conditioned problems are improved by changing the multiple parameters.

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Input shaping refers to a particular command shaping technique that exploits the convolution of the reference signal with a sequence of impulses to reduce the system vibrations. The method requires only estimates of the natural frequencies and damping ratio. Not only vibration eduction of the flexible structure, tracking of trajectory is important in the fields of both spacecraft dynamics and robotics. This paper presents a method of input-shaped control for a flexible manipulator, and shows by numerical simulations that the command input shaping technique is highly effective for the near-minimum-time tracking control.

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The objective of this study is the loosening detection of bolted joints without human involvement by applying the concept of structural health monitoring. The smart washer consists of the cantilever available to detect bolt loosening by using flexibility of cantilever and self-sensing/actuation function. The loosening is detected by the dynamics change of a smart washer system. This paper propose to apply the supervisor based on the modelbased FDI (Fault Detection and Isolation) technique for the detection of loosening by using multiple observer. The experimentations were performed to verify the possibility of the observer-based loosening detection. Improvement of loosening detection accuracy was confirmed by comparing the proposed to previous method.

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The purpose of this paper is to present generalized models of compact folding/wrapping method of flat circular membranes around a central hub using modified Archimedean spiral configurations. By using the formulated simple angle relations between fold-lines, various kinds of wrapping models are shown to be easily designed. The present models are expected not only to design a fundamental modeling of sail wrapping of solar-sail spacecraft but also to be used for instructional materials with edutainment.

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Although it is not impossible to manufacture 3 dimensional structures by an Origami technique using conventional flat sheet, from the engineering standpoint, the range of producible models become confined for the complexities of the manufacture procedure. Therefore we try to use geometrically prescribed uneven sheet with periodical indents instead of a flat sheet to achieve an easy processing of 3D structures. By using such sheets, several geometrically simple structures such as rigid mast and plates were manufactured.

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Dia-Core is a newly devised core panel formed by gluing/welding of two same shaped panel pieces which have periodically indents. It has good cost performance due to easy press forming. Therefore, it is expected to become new core materials which can be compete with honeycombs from the total points of view. The basic model of Dia-core is based on Octet-Truss developed by Fuller, and it consists of tetrahedra and octahedra. By varying the geometrical patterns that appear on the panel surfaces, various shaped modified models are devised systematically. In this paper, it is clarified that these pattern variations can be ruled by two geometric parameters, truncation [k] and separation [s]. Next, by numerical simulation using FEM, effects of these two parameters on the representative properties of Dia-Core, bending rigidity, are clarified.

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In this paper, a new type drive system of the MEMS(micro electro mechanical systems) resonant-type optical scanner is proposed and researched feasibility of a practical use. In this drive system, scanner mirror is supported with two pairs of stepped beams. When the harmonic axial force is applied to the ends of the supporting beams, torsional vibration of the mirror is excited due to the bending deformation of the beams. The effects of the beam dimensions on resonance frequency, amplitude of rotation angle and maximum value of the first principal stress are investigated by comparing simple theoretical results with FEM-based simulation.

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In this paper it is investigated whether the resonance frequency of a Helmholtz resonator is changed and the noise in a vehicle cabin is reduced by fabricating the throat of a resonator with double steel tube and attaching it to the resonator. As the frequency response of sound pressure level at a passenger's ear position is measured by an experiment the reduction and splitting of a resonance peak is successfully obtained as shown from the analysis by the finite element method.

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Plane tiling theory used to design new core structures is employed to create two kinds of different truss core panels called Tetrahedral Truss Core Panel and Honeycomb Truss Core panel, corresponding to two different steps of the tiling process. Models are made by C.A.D and their acoustical properties such as sound power and radiation efficiency are simulated with different materials and at different frequencies to show that the cores configuration and geometry have an impact on those properties. The results show that TTCP has lower acoustic power than HTCP with a higher radiation for both panels at high frequency.

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Honeycomb panel is widely used as flooring or wall material in various structure including buildings, aircraft, train and so on due to high stiffness and lightness at present. Honeycomb panel, however, has a disadvantage that adhesive used to glue honeycomb core and top plate may burn by fire. On the other hand truss core panel has equivalent stiffness as honeycomb panel and is expected to be a alternative to honeycomb panel as it is safer for fire. To replace honeycomb panel with truss core panel, it is necessary to investigate the stiffness of truss core panel for bending, shear, compression and so on. The paper chose the bending case and made a three point bending model of truss core panel. Four cases of analysis with/without work hardening effect, using two types of shell formulation were performed. The study showed the effect of work hardening was very important to assess bending stiffness of truss core panel. And it also be observed that the use of suitable shell formulation is necessary to obtain reliable result.

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This paper deals with a new core structure panel, called Truss Core Panel. We consider this Panel is useful for environment concern, because this panel has high-specific stiffness, such as Honey Comb Panel. And more, this Panel is formed by Press Forming. So, we think it leads more general versatility unlike Honey Comb Panel that has multi forming process. And now Truss Core Panel changes its core shape based on Truncation parameter, k and Separation parameter, s. So we think this feature changes mechanical characteristic of Truss Core Panel. In this paper, we examined formability of Truss Core Panel according to Truncation parameter, k and Separation parameter, s. through the dynamic FEM simulation. As a result, Relation between Thickness Reduction and Truncation parameter, k became nonlinear in certain Separation parameter, s. And we examined strength characteristic of Truss Core Panel after Press Forming. So this panel has the effect of work hardening. As a result, Relation between Mean Load cf Panel and Truncation parameter, k became almost linear despite Separation parameter, s. In conclusion we showed Formability and Strength Characteristic affer Press Forming do not always relate in the same condition.

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This article introduces some types of bifurcation control methods with the aim of realizing vibration control and motion control for mechanical systems. In the first part, we deal with stabilization control methods based on bifurcation control for nonlinear resonance which is the 1/3-order subharmonic resonance in a magnetically levitated body and the hunting motion in a railway vehicle wheelset. The second part deals with positive utilizations of nonlinear phenomena by the generation and the modification of bifurcation phenomena. We propose the amplitude control method of the cantilever probe of an atomic force microscope (AFM) for the measurement of biological samples and carry out the motion control of a two link underactuated manipulator with a free link and an active link without state feedback control based on positive utilization of nonlinear phenomena.

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This paper deals with mechanism of excitation in a curved fluid-conveying pipe, which is hanging horizontally and is supported at both ends. After predicting mechanism of excitation on the basis of physical consideration of governing equation, the first mode forced vibration and the parametric resonance of a planar curved pipe vibration were confirmed in the experiments. In addition, we discussed the above phenomena, especially the parametric resonance, by the application of the dynamical system theory. As a result, an approximate analysis solution was obtained.

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