This study presents experimental and analytical results about the influence of brake pad thickness on disk brake squeal. First, we prepared pads with different thickness and experimented on squeals test with the simple system instead of an actual disk brake in order to clarify the influence of brake pad thickness. Second, we studied correlation between dynamic stiffness and brake pad thickness. Finally, we analyzed the mechanism of squeal generation, which is caused by pad stiffness change due to pad thickness change, with Surface-contact model based on the experimental results.

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The self-synchronized phenomena generated in a coupled self-excited oscillators acting on Coulomb's friction are investigated experimentally and analytically. This system consists of two oscillators coupled in series and set up on a belt conveyer. In this system, the stick-slip vibration often occurs resulting from the friction. The shooting method is improved for such discontinuous systems to analyze the self-synchronized solutions and its stability. As results, there are mainly two stable regions on the branch of the self-synchronized solution. In addition, we analytically shown the unstable regions alternately exist on the branch of Model, which the blocks vibrate nearly in-phase, caused by the internal resonance.

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The response of the structure subjected to nonstationary random vibration such as earthquake excitation is nonstationary random process. Calculating method for statistical characteristics of such a response is complicated. Mean square value is one of the representative statistical values. Then, practical and simplified method to obtain theoretical statistical value is required. Integral of mean square value of the response corresponds to total energy of the response. In this paper, a simplified calculation method to obtain integral of mean square value of the response of the structure is proposed. Nonstationary random p input excitation is given as product of envelop function and stationary random process. Mean square value of nonstationary random response is assumed to be product of square of envelop function and mean square value of stationary random response. It is found that the proposed method gives exact value of integral of mean square value of the response

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The non-Gaussian response characteristics of a non-symmetric nonlinear 1-DOF system subjected to non-white excitation are investigated. Applying a previously-developed method, which contains the Non-Gaussian equivalent linearization technique and the use of the moment equations approach, the stationary response is calculated. Using kurtosis and skewness as indicator of the non-Gaussianity, the non-Gaussian response characteristics are quantitatively evaluated. The relationships between a couple of equivalent linear coefficients are also illustrated. The numerical results show the effects of the non-symmetric properties of the system and the dominant frequencies of excitation upon the non-Gaussian response characteristics.

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The Static Analysis is proposed as a method of calculating the critical wind speed of overturning of railway vehicles. In this method, the lateral acceleration of a vehicle under running is assumable by the linear function that passes through 0.98 m/s^2 at a maximum speed of the vehicle, and influences the wheel loads. In this paper, the authors studied the correlation between the lateral acceleration and the wheel load, to confirm that the assumption of the lateral acceleration is appropriate. As a result, it was apparent that their correlation was high in the frequency range 0-1 Hz.

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This paper describes an experimental study on self-excited vibration of a vibrating screen. We investigate the motions of granular material, the effects of frequency of forced vibration and mass flow rate of granular material from the vibrating screen. Consequently, self-excited vibration is observed, when the acceleration of vibrating screen is more than 1 g. Fluctuation of flow rate of granular material causes a self-excited vibration.

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This paper deals with the repeated impact between two identical spheres in which the strain rate dependency of the material has been considered. The experiments wens conducted by using steel balls (JIS SUJ2). Then the numerical simulations were earned out by using finite element analyses. The applicability of the prediction fbrthe coefficient of restitution proposed by Graham was examined for the case of this study. It was found that the coefficient of restitution increased with the inpact number and the contact duration decreased with the impact number. The expression for the coefficient of restitution proposed by Graham gives the valid results only if the initial coefficient of restitution was given accurately.

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This sheet deals with analysis of the oblique impact system, which is composed of the ball and flat plate. The impact system is modeled by both a nonlinear spring and a nonlinear dashpot using Hertz's contact theory. This model is applied to the oblique impact system of ball. The characteristics of the oblique impact were obtained by using this model. The results show that experiment and simulation are carried out to demonstrate the accuracy of the proposed model, and good agreement is shown. Also, the results show that the spin rate was proportional to tangential impulse.

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Impact vibration of two beams was treated as an example of the impact vibration of continuous systems that must consider vibration modes and the followings were made clear. (1) By adopting six beam modes, the theoretical result and the experimental ones about bifurcation diagram agree well each other qualitatively, and the characteristic of the diagram is a little different from that of the beam and the wall system. (2) From the viewpoint of the engineering, the transition from periodic motion to chaos is interpreted as the grazing bifurcation and its bifurcation changes a little depending on the phase of beams. (3) The tendency of the energy levels of the modes excited by the impact is similar to the case of the impact vibration of the beam and the wall.

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In order to inspect the safety of buildings or structures when they are damaged, a non-destructive inspection is required to identify the location and the degree of damage. One of the analysis methods for such identification inverse problems is the physical properties identification method using filtering theory. This report, as an application example, examines the validity of this method based on specific numerical calculation samples, together with formulating the analysis algorithm, using the multiple damage identification problem of a beam structure as the subject.

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This study investigate an identification method for physical parameters of golf clubs by golf swing robot by using data of deformation of the club-shaft and input torque in swinging trials. In this method, parameters of the golf club are identified by least-square method. Vibration modes of the club-shaft are necessary to estimate actual physical parameters such as stiffness, El, of the shaft and density of the shaft, pA. However, these vibration modes are not available at the beginning of identification, because these physical parameters, which have not been determined, are required to derive vibration modes. Therefore, temporary vibration modes are assumed for the initial condition of proposed method, and the physical parameters are estimated by iterative calculation between the estimation of physical parameters by using assumed/estimated vibration modes and the estimation of the vibration modes by using estimated physical parameters. Proposed identification method is confirmed by numerical simulation.

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The problem in the ceramic grinding is a tool failure after a long time operation. It gives a crucial damage to the work piece. Usually, rotational frequency and its multiples are utilized for machine condition monitoring. However, it is difficult for us to clearly observe the frequency components in the ceramic grinding by direct use of the Fourier transform. In this research, we measure the acceleration of the work piece during the grinding process, and the Hilbert transform is employed as a pretreatment of the Fourier transform. Significantly good results are obtained by means of the proposed method.

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Identification method for the nodal lines of a plate by one sensor is proposed. From the theory of vibration of a single DOF system, increasing the frequency of excitation through the resonance point converts the phase angle between the excitation and the response from in phase to 180 degrees out of phase. In the vibration of continuous system, responses have opposite direction in both side of nodal line. These properties make the anti-resonance points, which correspond to nearly zero amplitude between two resonance points in the frequency response function. The nodal lines of a plate can be identified by the anti-resonance points. The power spectrum of the response subjected to impulse force hammer is similar to the frequency response function, because the impulse force has almost uniform frequency components. Using the shape of the minimum points of power spectra of the responses of the repeated measurements by one sensor, successful identification of the nodal lines of a plate is demonstrated in this paper. It is shown that the identified results by the proposed method are equivalent to the results by the anti-resonance points, and agree well with the FEM results.

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To reduce vibrations of such objects as machines and structures placed in a row, joint dampers are often used. In this paper the optimal design of a joint damper is considered. It is found that depending on the mass ratio or rigidity ratio of the objects, different conditions must be used to determine optimal parameters. Methods for determining the optimal parameters based on these conditions are proposed.

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An autoparametric vibration absorber using a spring-mass pendulum which consists of a spring and a mass is proposed in this report. The spring-mass pendulum has two resonances which appear due to a parametric resonance of the pendulum and a resonance of the spring-mass system. Two resonances of a main system are suppressed by a dynamic absorber using the spring-mass pendulum which has two resonances. Double floors structure is made as the main system and two resonances of the structure are controlled in experiment. The dynamic absorber effect is discussed by the simulation.

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Elevated bridges supported by rubber bearings vibrate due to heavy moving vehicles, emitting heavy impact sounds around the joints. In this study, the vibrations of beams equivalent to the elevated bridges are analyzed, taking the elasticity of rubber bearings into account. The results shows that the end of the elevated bridge is more likely to vibrate than any other positions because higher modes, which are anti-node at both ends, are mainly excited, and the vibration at the ends of the elevated bridges causes impact low-frequency noise.

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In this study, the simple method to isolate the ground vibration due to a construction machine, which is a rock drill, is proposed by using a dynamic damper. The ground is modelled by FEM and the external force is set as the repeated impact. The ground vibrations at some estimation points are calculated for various location of dynamic damper. As numerical results, the ground vibration is most suppressed when a dynamic damper is set near the vibration source and the dynamic damper increase the isolation effect of trench.

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Nonlinear lateral vibration of a vertical cantilevered pipe with an end mass is studied for the case that the upper end of the pipe is excited periodically in a horizontal direction. The fluid velocity of an axial flow in the pipe is slightly over the critical value, above which lateral pipe vibration is self-excited by an internal flow. First, the effect of horizontal excitation on nonplanar flow-induced pipe vibration is examined by solving numerically the four first-order ordenary differential equation, which govern the amplitudes and phases of nonplanar pipe vibration and are coupled though the nonlinear terms. Second, the experiments were conducted with a silicon rubber pipe conveying water, and the spatial behavior of the pipe vibration were observed using two CCD cameras. The typical effect of horizontal excitation, which has been predicted in the theory, is confirmed qualitatively by experiment.

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It is known that chatter vibration of a cleaning blade occasionally causes a squeaking noise. This reasearch aims to investigate the basic characteristics of the motion of the blade, as the first step in determining the cause of the chatter. First, an elastic beam model is presented, and its governing equations and boundary conditions are derived. Next, the static state is discussed, with emphasis placed on the effect of friction. Finally, an experiment is conducted using a simple apparatus in order to verify the properties of self-excited vibrations.

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The characteristics of solutions of finite difference approximated beam are discussed for the application of wave control. The characteristic solutions in time domain are obtained as conjugate complex solutions including Bessel function, which can be realized by linear combination with conjugate complex constants ; however, an arbitrary property is unresolved. By investigating both frequency characteristics of solutions and control response of both-ends controlled beam, the best combination of constants has been shown.

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The carbon fiber reinforced plastics (CFRP) is classified as high performance composite materials that are superior to conventional materials in the specific strength and stiffness ratios. They are applied to light-weight structures in aircraft and space industries. In such fields, wings are often approximated as a parallelogram plate, but the past studies were carried out by using the classical plate theory. This analysis is however based on the shear deformation plate theory (FSDT). A Ritz method is used to calculate natural frequencies of symmetrically laminated parallelogram plates, and the layerwise optimization method is used to optimize the best lay-up designs. It is shown that the LO method is applicable to the parallelogram plates successfully.

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When the agricultural machinery runs on-road the vibration and the noise caused by the interaction between the tire lugs and the road surface are inevitable. In this study, the test equipment is manufactured to measure the motion of the rolling agricultual tire with ground contact and lug excitation force are derived. Next, natural frequencies and natural modes are obtained by experimenatl modal analysis. By comparing the characteristic for rotationl speed of lug excitation force with obtained natural frequencies of the tire, the influence of vibration characteristics of the tire on lug excitation force are investigated.

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KUKAI is a nano-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 nano-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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When a plate-like object is rubbed by rubber, friction-induced vibration is generated. For reducing the friction-induced vibration, we experimentally investigate the characteristics of the vibration of a rectangular glass plate. The results show that the frequency of the friction-induced vibration is almost the same as the natural frequency of a glass plate. The vibration is generated when the second natural frequency of the rubbing system is close to the natural frequency of a glass plate. Then, we examine the effect of a dynamic absorber mounted on the glass plate. The results demonstrate that the damping of a dynamic absorber is effective for suppressing the friction-induced vibration. Numerical simulation is also performed using a simplified analytical model. The calculated results agree qualitatively with the experimental ones.

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The use of artificial bone graft substitutes has increased as the surgical application for large bone defect. Beta-tri calcium phosphate (β-TCP) is the only bone substitute which is replaced and absorbed to the bone. In the present study we investigated whether low-intensity pulsed ultrasound (LIPUS) accelerates bone ingrowth into the pores of β-TCP carried with bone marrow. Thirty six rats were used and these rats were divided into 4 groups, control group, β-TCP with LIPUS group, β-TCP carried with bone marrow and β-TCP carried with bone marrow and LIPUS. Specimens were harvested on 2, 4 and 6 weeks after implantation, and were analyzed by HE and TRAP staining. The new bone formation in the β-TCP carried with bone marrow and LIPUS was significantly larger than that of similarly implanted P-TCP that was not exposed to LIPUS. The new bone formation in the P-TCP without bone marrow was not observed. LIPUS application does not significantly increase the activity of osteoclast in comparison with similarly implanted β-TCP that was not exposed to LIPUS.

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Many individuals and in particular elderly suffer from bone diseases like Osteoporosis, and bone fracture or cracking are problems which many athletes as well as ordinary people tackle, since they take rather long time to get treated. It has been observed that exposing bone cells to mechanical vibration with special frequencies could cause dramatic variations in Osteoblast cell proliferation rate. Previous works proposed the phenomenon is driven by the cell mechanical sensors, by which it senses mechanical manipulations. On the other hand, treatments that employ ultrasound in order to increase the repair rate of bones are getting popular. Hence modeling cells against loads in order to predict their response to mechanical waves is indispensable to treat diseases using mechanical vibration. Also using a more advanced model concerning the interaction of cells with their surrounding, it would be possible to predict and analyze the effect of different body activities on the cells, that could be useful yielding a more detailed understanding of Osteoblast life. In this study we developed an overall mechanical model using a novel method, taking into account the uniaxial instant and viscoelastic parameters for load bearing members of a single Osteoblast cell (See Fig.A1). The model was considered to be overall, since the whole body of the cell was considered as a single viscoelastic material, rather than a combination of its load bearing members such as membrane and cytoskeletal fibers. Osteoblast cells have been seeded on an extra-soft gel string, whose mechanical characteristics had been calibrated, and the string has been stretched, while being observed under a microscope. In this way, response of a single cell has been monitored during the load application period. This setup then has been modeled by an analysis software, in which the so called gel plate was modeled as an elastic body, using results that had been obtained from gel calibration tests. Cell load-bearing members were modeled initially as a member with unidentified mechanical properties. A trial and error method was used in order to approach a well-fit relationship between the cell deflection, observed during the experiment, and cell overall force. A creep test and a stepwise tensile test were conducted on the cell. Fig.A2 depicts strain time histories that have been obtained from the creep test, and Fig.A3 is the load pattern that was applied to the stepwise tensile test.

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In this study, a micro sensor-actuator device is developed to enforce dynamic stimulation and to detect changes of mechanical properties by the stimulation induced in a cultured adhesive cell. The micro device utilizes a clamped-free beam type vibrator of which the vibration is excited by a piezoelectric ceramic. The device has an ability to measure mechanical property of a cultured cell as compliance. It was mounted on a micromanipulator system, while dimensions and morphologies of the cells were measured by an inverted phase contrast microscope system. Experimental studies have been carried out by using cultured normal human osteoblast (NHOst), because of its sensitivity to external mechanical stimuli. Cytoskeletal condition was controlled by repolymerization time after depolymerization treatment with a use of Cytochalasin D. The method has shown enough capability to detect difference of mechanical properties due to changes of cytoskeletal stress fiber architecture in NHOst.

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In this study, a three-dimensional vibration stage is developed. This device provides the ability to simulate mechanical environment of the cells in vivo. Three piezoelectric ceramics are bonded in three orthogonal directions, so that the V-shaped vibration stage is able to mount a standard-sized culture dish and perform three-dimensional vibration up to around 80μm in each direction. Because of its simple structure, a sterilization treatment, which should be done before setting the vibration stage in a CO_2 incubator to avoid contamination, can be carried out without difficulty. Focusing on osteoblast's character, which is sensitive to external mechanical stimuli, a normal human osteoblast (NHOst) is stimulated by the developed three-dimensional vibration stage. In order to estimate effect of dynamic stimulation upon cultured cell, we define parameters of projected area and slederness ratio of the cultured NHOst. It is found that the vibration stimulation affects cell morphology.

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A rational method of dimensional reduction is developed in order to analyze accurately a nonlinear vibration of a large-scale system with locally strong nonlinearity. Nodes without nonlinear excitation are transformed into the modal coordinates and the only modes whose effect on computation accuracy of the vibration analysis is significant are extracted. On the other hand, the remaining modes whose effect on computation accuracy is small are appropriately approximated and are eliminated. The low-dimensional model is constructed by these procedures. The effectiveness of this method for a straight-line beam structure acting non-proportionally damping is verified by the computational results.

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A rational reduction method using modal analysis is developed in order to analyze accurately a large-scale, global nonlinear system. In the proposed method, the state variables of weakly-nonlinear nodes are transformed into the modal coordinates, and a small number of modal coordinates which have a significant effect on computation accuracy of the vibration analysis are extracted. On the other hands, the remaining modes which have little effect are appropriately approximated and then eliminated. A very accurate low-dimensional model is constructed by these procedures. The effectiveness of this method is verified by the computational results.

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Gear rattle of multi-step helical gear system is treated. Mesh stiffness variations and higher harmonics of driving torque are considered in the system. The effects of higher harmonics of driving torque are studied by numerical analysis. As a result, the followings were made clear. (1) First harmonics of driving torque generates higher harmonic resonance and higher harmonics of driving torque generates the main resonance, hence the interaction of these two resonances makes the amplitude of the resonance large. (2) Because of interaction of higher harmonics of driving torque and mesh stiffness variation, resonances like gear noise occur with many side-bands in low frequency region, and the region of the rattles becomes wide. (3) Gear rattle in the case of small constant torque is almost chaos and chaos by intermittency is recognized.

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This paper investigates a synchronizing phenomenon of oscillators, coupled together in the form of the evolving complex network. The percolation theory is introduced to represent the evolving complex network, where nodes and links correspond to the oscillators and signal transfer relation respectively. Numerical experiments show that the synchronization phenomena depend on the structures of the evolving complex networks.

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The authors have developed a synchronous vibration mechanism for a tamping rammer used to compact cohesive soils and asphalt. This system consists of three mass-blocks coupled by springs, and the rotor-type oscillators are mounted individually on the lower blocks. The nonlinearity due to the impact behavior between the lower blocks and a ground is approximated by piecewise linear characteristics. In this report, the self-synchronized solutions and its stability are analyzed by applying the improved shooting method for impact vibration analysis. The results confirmed that the self-synchronized solution which can achieve a good balance between utilization of vibration and vibration control exists in the present system.

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The purpose of this research is to develop a synchronous vibration mechanism in order to reduce the hand-transmitted vibration. In this paper, the model equipped with four oscillators is investigated experimentally and analytically. As a result, the vibration pattern that can realize not only utilization of vibration and vibration control at once but also reducing the development of rotational vibration which has been problem in our previous report is generated in this model. In addition, the influence of the combination of each weight's rotational direction is examined.

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Nonlinear vibrations of an elastic structure, with a nearly square liquid tank obliquely attached, under horizontal harmonic excitation are investigated. When the tuning condition, a ratio 1:1:1, is satisfied among the natural frequencies of the structure and two sloshing modes (1,0) and (0,1), the equation of motion for the structure and the modal equations for sloshing are derived considering the nonlinearity of sloshing. Then, van der Pol's method is employed to determine the frequency response curves. The influences of the system parameters on the response curves are investigated. Hopf bifurcations occur and amplitude modulated motions including chaotic vibrations appear depending on the excitation amplitude and frequency. The validity of the theoretical results was confirmed by experiments.

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Experimental results are presented on chaotic vibrations of a shallow cylindrical shell-panel under in-plane forces. Opposite edges of the panel are clamped and the other edges are free. One side of the clamped edges is connected with spring plates and is stretched to an in-plane direction. By exciting the panel with periodic lateral acceleration, chaotic responses are generated in specific frequency regions of excitation. The chaotic responses are examined with the Fourier spectra and the maximum Lyapunov exponents. It is found that the chaotic responses are generated due to the internal resonances. Applying the Karhunen-Loeve method, contributions of vibration modes on the chaotic responses are clarified. Under the in-plane force, which is free of in-plane constraint, the symmetric mode with one circumferential half wave and one longitudinal half wave contributes dominantly to the chaotic responses. Under the in-plane tensile force, which is 78% for the magnitude of the buckling load, the asymmetric mode with two circumferential half waves and one longitudinal half wave shows a large contribution.

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Recently, there is a high expectaion for biological samples to be observed in liquid by the use of Atomic Force Microscopes (AFM). However, viscous damping makes it difficult to observe the samples in liquid using conventional methods. Moreover, it is required that a cantilever oscillates with a small amplitude to prevent the contact between the cantilever and the samples. In this research, we proposed a microcantilever which behaves as van der Pol oscillator. Then, we realized a self-excited oscillation with a small steady state amplitude.

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Composite materials (fiber reinforced plastics:FRP) present the excellent possibility of design for changing in structural stiffness with tailoring the fiber-direction or ply-orientation. In this work, two simple analytical models are proposed for estimate the influence of the bend/twist deformation coupling on natural frequencies of cantilevered composite plate. Frequencies and modes are calculated using Ritz method based on the beam-like(CRLP) model or plate-like model. Beam like model is convenient for obtain the vibration characteristics of bend/twist deformation coupling of unbalanced ply laminate as compared to the plate-like one.

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The vibration intensity (VI) method is one of the techniques to visualize vibration transmission paths. Even if VI method is applied to the vibration field with a complete vibration mode, the transmission of the vibration energy is not detected. However, if another excitation condition is added to the vibration field with a vibration mode to cause an energy flow, a curved energy flow pattern that is different from the energy flow pattern without the vibration mode is detected by VI method. The purpose of this research is to investigate the occurrence condition and the generation mechanism of curved energy flow

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Shell Structures is often employed in mechanical structures. In the vibration transmission in curved shell, the flexural component of vibration energy is transformed into the extensional component and vice versa. A previous research reported that the extensional component fraction was higher for smaller curvature radius. The purpose of the present research is to investigate the behavior of both components of vibration energy flow in L-shaped model with small curvature radius by using Vibration Intensity (VI) method as a vibration energy flow visualization method and FEM analysis. Analysis results led to the suggestion that the extensional component fraction reach a maximum for smaller curvature radius.

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Composite materials, containing carbon nanotubes or vapor-growth carbon fibers, provide excellent thermal conductivity and specific intensity, and the thermal characteristics of the materials have been studied intensively in recent years. In the present report, a method of vibration analysis is proposed to obtain natural frequencies and mode shapes of circular plates composed of VGCF and aluminum layers. The Ritz method is used to derive a frequency equation. The finite element analysis is also made to calculate frequencies of the plates for comparison, and the accuracy of the Ritz solution is established.

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This paper presents a numerical optimization method for optimal configuration design of shell structures. It is assumed that the shell surface is varied in the out-of-plane direction to the surface in order to obtain the optimal free-form shape, and the thickness is not changed with respect to the shape variation. A solution to the maximization problem of vibration eigen value subject to a volume constraint is proposed. With this solution, the optimal shape is obtained without shape design parameterization. The problem is formulated as a non-parametric shape optimization problem. The shape gradient function is theoretically derived using the material derivative formulas, Lagrange multiplier method and the adjoint variable method. The Robin type traction method is applied to determine the free-form shell while minimizing the objective functional. The calculated results show the effectiveness of the proposed method for optimal free-form design of shell structures.

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Recently, the laminated shells made of FRP (fiber reinforced plastics ) is used as a light weight structural applications. Many laminated composite shells among these applications are made by Filament Winding (FW) forming. In this paper, free vibration analysis was showed for FW laminated composite circular cylindrical shells simply supported edges. The formulation is based on the Flugge-type shell theory using the Classical lamination Theory (CST) and First-order Shear Deformation Theory (FSDT) .The analytical result was compared with the modal testing result. This study is assumed to be a base of the analysis of the vibration characteristics of the angle ply circular cylindrical shells.

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A method of analysis is presented for determining the free vibration frequencies of hybrid laminated plates, and the layerwisr optimization method is used to determine the optimum fiber orientation angles for the maximum fundamental frequency under general edge conditions. The hybrid plates made of aluminum core and CFRP skins are made for reducing the material costs. Based on the first-order shear deformation theory (FSDT) applicable to thick plates, the Ritz solution is used to derive a frequency equation, and these results give good agreement with those from finite element method. An extensive set of numerical results is given in tabular and graphical form, illustrating the maximum fundamental frequency with the optimum lay-ups of the laminated hybrid plates. Comparison of the results gives tendencies caused by boundary conditions and laminated composition.

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Light weight structure using fiber reinforced plastics(FRP) are made by variations forming types. In this study, circular cylindrical shells are formed by using simply FW forming unit which has been designed by this lab.. Natural frequency and mode obtained by this unit are compare to the analytical resules. As the results, this unit is convenient for measuring vibration characteristics as the natural frequency and modes.

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This paper presents free vibration characteristics of composite plates with visco-elastic material. For this purpose, the parameter identification for the stress-strain relationship of two kinds of visco-elastic materials is carried out by using fractional derivative model, and then natural frequencies and specific damping capacities of the composite plates composed of isotropic material and the visco-elastic material are evaluated analytically by using the Ritz's method based on the Discrete Layer Theory and Classical Lamination Theory. Finally, the experimental study is also carried out by using the experimental modal analysis, and the accuracy of identified models is discussed form the comparisons of numerical and experimental results.

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Experimental results are presented on chaotic vibrations of a circular plate with initial deformation. The plate has the characteristics of a softening-and-hardening spring with snap-through due to the initial deflection and in-plane compression. Under periodic excitation, chaotic responses are observed in the two frequency regions. Chaotic time responses are recorded. The responses are inspected by the Fourier spectrum, the Poincare projection, the maximum Lyapunov exponents and principal component analysis. Chaotic response of a lower frequency region is generated by the internal resonance and shows large amplitude with dynamic snap-through. Chaotic response of a higher frequency region is induced by the combination resonance. In the two frequency regions, the maximum Lyapunov exponents are compared. As a result, the maximum Lyapunov exponent with the dynamic snap-through is larger than without dynamic snap-trough.

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Vibration characteristics of a lug tire exposure to axial excitation are examined. Natural frequencies and mode shapes are obtained by experimental modal analysis. The results show that the lower frequencies exist as several natural modes than the radial dominant modes. The lug tier model based on a thin cylindrical shell is introduced and the natural frequencies and modes are analyzed. Parameter identification is carried out using experimental results, which correspond to axial modes and the radial natural frequencies are compared. The calculated results using identified parameters are identical with the experimental results and the validity of the tire lug model is verified.

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This paper proposes a semi-active method for vibration control of aluminum plate using piezoelectric energy-harvesting technique. The energy-harvesting technique scavenges electrical energy from the vibration energy of structure using piezoelectric transducers embedded or bonded to the structure, and requires no external power sources. Combining the piezoelectric energy-harvesting technique with semi-active method enhances the performance of vibration suppression. A vibration suppression experiment of aluminum plates is carried out to verify the validity of the present method. The results show that the proposed vibration control system is effective.

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An analytical method to treat flexural vibration of railway vehicle carbody is investigated. From several measurement results for actual railway vehicles, it has been found that the relative vertical displacement between roof and floor couples strongly with lateral deformation of side panels. An analytical model, therefore, has to express such coupling effect correctly. A curved beam, in which circumferential and radial deformation couples each other, is introduced to express the deformation of side pillar in this study. The strain energy of the curved beam is derived based on a shell theory, and some numerical calculations are carried out. A straight and curved beam coupled system is proposed as a reduced system representing side panel of a railway vehicle carbody. Numerical result shows that the beam system can express the coupling effect between roof-floor relative vertical displacement and side panel lateral deformation successfully.

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