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| 1.
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金, 哲紅 ; 三輪, 卓 ; 陳, 志超 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />The new sealant layer is presented, which is easier to include into the manufacture process of the tire in comparison with the previous research. The performance of the present tire was
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investigated, and it was clarified that there was no air leak when nails broke it. Vibration characteristics of the present tire were analyzed theoretically and experimentally, and the effects of the sealant on the road-ability and the road noise were investigated. Using the analysis, it is shown that vibration transmissibility decreases in the present. The impact characteristics are also discussed. The transmissibility is also decrease when the impact load applies to the tire, and load noise is also decreased.
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| 2.
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長屋, 幸助 ; 林, 乃生幸 ; 大関, 健一郎
概要:
application/pdf<br />Journal Article<br />This article presents a new levitation technique, which uses a small superconductor and a set of permanent magnets. In the system, a small superconductor is connected to the bottom of the vertical
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shaft. The gravity force and axial vibration force are supported by the superconductor. A circular permanent magnet is attched to the top of the shaft, and the other circular permanent magnet lies at the frame. The N-pole of one of the magnets faces to the S-pole of the other magnet, so a drag force acts between the magnets. The drag force is unstable in the axial direction, but the pinning force in the axial direction of the superconductor makes it stable. There is a restoring force in the horizontal direction between two permanent magnets, and in addition, there is a pinning force of the superconductor, so that both ends of the shaft are stable in the horizontal direction. This implies that the levitated shaft is stable without control. In general, controls have to be made in either axial or horizontal direction when the ordinary magnets are used. The levitation technique presented in this paper has advantages, Because, in order to have stable levitation, only one small superconductor is required, and a cooling system is simple. A method for passing through the critical speeds is also presented. In the method, rotating conductor disc is used to have the electromagnetic damping. Both the analysis and experiment are presented.
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| 3.
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長屋, 幸助 ; 湯澤, 秀人 ; 村上, 岩範
概要:
application/pdf<br />Journal Article<br />Since a commutator of the DC-motor is divided into a number of segments to have the torque in the circumference direction, the currents in the coils of the rotor vary and have alternative
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waves during the rotor rotation even in a constant input voltage. The currents become sharp waves, so that they have high frequency component. This implies that the rotor shaft and the case of motor are excited electromagnetic forces with high frequency components. Since high frequency noises are loud when they are input to human ears, so that when high frequency vibrations are suppressed, noises become small. From the situation, this paper discusses a method of noise reduction of Dc Motor. In the method, the current waves are controlled to be sinusoidal waves. The method and the control algorithm are given. In order to validate the method, experimental tests are carried out. It is proven that our method is applicable to the motor noise control.
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| 4.
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李, 連進 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />We present a system for reducing noise from structures using electromagnetic vibration absorbers. Conventional design techniques for vibration absorbers are not appropriate for noise reduction
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absorbers, because higher-mode vibrations exert strong effects on noise. Hence, we first derive an analytical expression for noise power including higher modes, then present a method for obtaining optimal parameters for noise reduction absorbers. In this method, noise power is taken as a function of cost, and the parameters are decided by using a neural network procedure. An improved algorithm of the neural network for obtaining the parameters is given, experimental tests are performed and the theoretical values are compared with the experimental data.
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| 5.
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李, 連進 ; 長屋, 幸助
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application/pdf<br />Journal Article<br />This paper presents a method for optimizing vibration absorbers on a flexible beam by means of a neural network procedure. Analytical results for the response of the beam with multi-absorbers
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have been obtained using a transfer matrix method. To achieve optimal control, a cost function composed of second-order nonlinear forms in terms of the displacement, strain, and frequencies was used. A method of minimizing the function was presented, in which input values, weights and output function were effectively controlled on the basis of the back-propagation procedure of the neural network method. Numerical calculations were carried out for an example problem. It is ascertained that the present method gives a better result than that obtained by the previously published method. The validity of the method and the analytical results was confirmed by experimental tests.
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| 6.
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王, 建春 ; 横田, 正二 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />Bending vibrations of a pipe system are trasmitted to an evaporator and generate noise in an air conditioning system. Hence to reduce noise, bending vibrations should be reduced. This paper
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presents a method for reducing bending vibrations of a pipe system by use of curve tube elements. As a first step, to discuss the validity of the simulation program based on our previous analyses, experimental tests have been performed, and the simulation results are compared with the experimental data for some typical cases. Then, the bending vibrations are calculated for pipe systems with the proposed curved tube elements. It is clarified that the method presented plays an important role in reducing bending vibrations in the pipe system.
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| 7.
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長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper discusses an actuator consisting of a permanent magnet with an electromagnet and a high Tc superconducting disc. An analytical solution for calculating levitation forces
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for the system was obtained. The obtained levitation force coincided with the previously published result. The equation of motion of the levitated body subjected to base disturbances under control was presented. Numerical calculations were carried out for some typical cases. Nonlinear vibrations of the system were first discussed, then the method of vibration isolation control using the direct disturbance cancellation combining the velocity feedback control was discussed. It was clarified that the present control method is valid for controlling the nonlinear system like the magnetically levitated superconducting body.
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| 8.
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長屋, 幸助 ; 鄭, 惟
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application/pdf<br />Journal Article<br />This paper discusses vibration control problems of a cantilever plate with variable width. A moment-type actuator using a moving coil was presented. A mothod for obtaining optimal feedback
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coefficients was proposed on the basis of neural networks. An analytial solution for the response of the plate under the control using the feedback coefficients was obtained. Numerical calculations were carried out for some typical cases. It is clarified that the present method is valid for controlling vibrations of plates.
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| 9.
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王, 建春 ; 長屋, 幸助 ; 横田, 正二
概要:
application/pdf<br />Journal Article<br />This paper presents a method for obtaining vibration response of a viscoelastic spiral rod having straight portions on viscoelastic supports. The expressions for calculating frequency
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response are obtained by means of the transfer matrix method, in which the exact solution of the differential equations with twelve state variables for the static deflection is applied. Inertia forces and rotatory inertia are included by making use of the point transfer matrix, and the bent portions are also considered by including the transfer matrix of coordinates. Numerical calculations were carried out for the rod with both an elastic portion and a viscoelastic portion carrying a mass at the end. In this problem, the rotary vibration is of importance because it generates noise, hence the location of the viscoelastic support which induces the rotary vibration of the mass minimum is discussed in detail. The fuzzy algorithm by which the optimal location of the supports is obtained is also presented.
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| 10.
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長屋, 幸助 ; 横田, 勇
概要:
application/pdf<br />Journal Article<br />In the preceding related paper, the authors discussed a plate-type magnetic damper with alternative magnetic poles. The paper presented the analytical expressions of eddy currents in the conductor
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and the damping coefficients for the single row of alternative poles. The damping effects of the damper having alternative poles of a number of rows and columns are different from those of the previous model. The present article discusses the damping increasing mechanisms for the plate-type damper with alternative magnetic poles of a number of rows and columns. The analytical expression for finding the eddy current patterns and the damping coefficient are obtained. Numerical calculations are carried out for some important examples. Since the present article gives the analytical expression and the numerical data of dimensionless damping coefficients, the results may be used directly in the practical design of such devices as vibration absorbers.
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| 11.
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龍, 宇光 ; 長屋, 幸助 ; 丹羽, 一
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application/pdf<br />Journal Article<br />The problem of a block repeatedly sliding, jumping and being conveyed inside a vibrating spatial tube is studied. Analytical models and equations are established in considering three kinds of
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motion states : relative sliding motion, flying motion and the bumping process. Precise investigations are carried out for the inclined frictions with component velocities and for oblique impact, which are seldom discussed thoroughly and are easily misinterpreted. The detailed motion of the entire response, called the ""subperiodic motion"", is revealed through numerical solutions. Fundamental effects of some basic parameters on the motion of the system are discussed. Appropriate ranges for both the frequency and the amplitudes of vibration are discovered to be very narrow. Experimental studies confirmed the theoretical analyses presented.
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| 12.
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樫本, 弘 ; 長屋, 幸助 ; 白石, 明男
概要:
application/pdf<br />Journal Article<br />This paper presents a method for solving the dynamic stress concentration of inhomogeneous rods having two-dimensional arbitrary curvature, variable cross section and infinite length
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subjected to in-plane bending wave excitation. In this analysis, the exact solution of the equilibrium equations for curved rods has been obtained, and the transfer matrix, based on the exact solutions with consideration of the inertial forces has been derived. At discontinuous sections, solutions of curved and straight rods have been connected by adjusting the boundary conditions. As examples, stress concentration factors in circular, elliptical and parabolic rods with variable cross sections have been calculated.
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| 13.
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王, 建春 ; 長屋, 幸助 ; 横田, 正二
概要:
application/pdf<br />Journal Article<br />This paper discusses free vibrations of a spiral rod with straight portions on a number of supports. Since the spiral portion is a three-dimensional structure, three-dimensional motions are coupled.
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Hence, this paper first presents the transfer matrix for a three-dimensional curved rod with supports, then the transfer matrix of a straight rod with supports is joined to that of the spiral rod. The frequency equations for the rod with consideration of three-dimensional motions are obtained. Numerical calculations are carried out for some typical problems.
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| 14.
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長屋, 幸助 ; 関口, 肇
概要:
application/pdf<br />Journal Article<br />A magnetic damper in which opposite poles are arranged by turns has great deal of damping effects as compared with a normal magnetic damper. However the reason of it has not been clarified, and the
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analysis has not been reported. To clarify the mechanisms of increasing dampings for the damper, this paper presents an analytical results for the eddy current, and the damping coefficient. Numerical calculations are carried out for some important examples, and the results are compared with those of the normal magnetic damper.
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| 15.
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樫本, 弘 ; 長屋, 幸助 ; 白石, 明男
概要:
application/pdf<br />Journal Article<br />This paper presents a method for solving the dynamic stress concentration of two-dimensional curved rods with circular cross section and infinite length subjected to in-plane bending wave
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excitation. In this analysis, the exact solution of the equilibrium equations for curved rods has been obtained, and the transfer matrix, based on the exact solutions with consideration of the inertia forces has been derived. At discontinuous sections, solutions of curved and straight rods have been connected by adjusting the boundary conditions. As examples, stress concentration factors in circular, elliptical and parabolic rods with circular cross sections have been calculated.
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| 16.
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永井, 健一 ; 大佐々, 吉宏 ; 長屋, 幸助 ; 武田, 定彦 ; 谷藤, 克也
概要:
application/pdf<br />Journal Article<br />An analytical method is presented for the bending vibration of a circular dise carrying concentrated masses, introducing a new mode of shape function to the Galerkin method. Deflection of
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the plate is expressed by a product of the mode shape function along radial direction and the circumferential periodic function. The mode shape function is assumed to be the sum of the product of the trigonometrical function and the finite power series. The coefficients of the power series are found to be satisfied by the boundary condition of the plate. Applying the Galerkin method, the number of sets of differential equation with second-order time functions are reduced. It is found that this method gives good accuracy to the natural frequencies within the small number of terms for unknown time functions
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| 17.
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長屋, 幸助 ; 山口, 俊澄
概要:
application/pdf<br />Journal Article<br />This paper presents a method for solving eigenvalue problems of various phenomena which are governed by the Helmholtz equation with an arbitrarily shaped outer boundary and a number of
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eccentric boundaries of arbitrary shape. In the analysis, the outer boundary condition is satisfied by means of the Fourier expansion collocation methed using the exact solution of the equation of motion. To satisfy the inner boundary conditions, the point restraints are added to the equation of motion, and the inner boundary conditions are satisfied by making use of a point-matching procedure. The equations for finding the eigenvalues are derived, and numerical calculations are carried out for cases of elliptical outer and a number of elliptical inner boundaries, and polygonal outer and a number of elliptical inner boundaries.
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| 18.
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長屋, 幸助 ; 平田, 康夫
概要:
application/pdf<br />Journal Article<br />This paper presents a method for designing a shape-memory alloy coupling between rods subjected to axial or torsional forces. The design formula is obtained by using the stress-strain
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relation. Since the coupling work is simple, the coupling has advantages for building members in dangerous zones. However, since the coupling force is not sufficient, it is disadvantageous for impact loads. To design coupling under consideration of impacts, this paper also discusses the transient response of the coupling due to various impact loads. Numerical calculations were carried out for some sample problems.
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| 19.
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長屋, 幸助 ; 山本, 哲也
概要:
application/pdf<br />Journal Article<br />This paper discusses a method for the optimal active vibration control of a plate using piezoelectric actuators. The analytical results under the optimal control were obtained by combining the
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eigenfunction procedure and the optimal active control theory. Numerical calculations were carried out for a clamped circular plate with concentrated masses which was controlled by bending moments generated by the piezoelectric actuators. It is confirmed that there is an optimal location for the actuator in each mode.
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| 20.
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小島, 宏行 ; 桑名, 秀晴 ; 疋田, 嘉一 ; 水野, 寿考
概要:
application/pdf<br />Journal Article<br />In a direct-drive robot, motors are directly coupled to the links without reduction gears, and high-grade control performance can be achieved. However, transient vibrations may frequently be
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generated owing to little friction and torque ripple of motors. In this report, the transient vibration characteristics of a horizontal two-link direct-drive robot are investigated theoretically. In the analysis, the torque characteristics are modeled in consideration of the torque ripple and the torque saturation characteristics of direct-drive motors, and the nonlinear state equation of the direct-drive robot is derived in consideration of the bearing elasticity of motors. Numerical simulation is carried out, and the effects of the torque ripple, the torque saturation characteristics and the bearing elasticity of direct-drive motors on the transient vibration characteristics of the direct-drive robot are demonstrated.
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| 21.
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小島, 宏行 ; 植杉, 献 ; 根津, 紀久雄 ; 坂本, 賢治
概要:
application/pdf<br />Journal Article<br />In this study, the mechanical system and the circular path control system of a horizontal two-link robot are constructed by utilizing step motors and harmonic drive gears. The effects of
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the excitation method of the step motors and the shape of the velocity pattern of the circular path control system on the dynamic characteristics are investigated. In the circular path control system, the control pulse generation algorithm to the step motors is constructed by use of inverse kinematics. From the experimental results, it is seen that the circular path control can be achieved with a comparatively high accuracy. Then, it is advisable for stable and fast circular path control without the failure phenomenon of the step motors, to utilize the two-phase excitation method of the step motors and the trapezoidal velocity pattern of the circular path control.
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| 22.
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長屋, 幸助 ; 荒井, 徳幸
概要:
application/pdf<br />Journal Article<br />This paper proposes an actuator in the magnetic levitation system using a permanent magnet and an electromagnet. In this system, the gravity force of the masses is supported by a strong permanent
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magnet in which two identical poles face each other. The vibration due to external disturbances is controled by use of the electromagnet by changing magnetic fluxes of one of the permanent magnets. The analytical expressions for obtaining the levitation force, spring constant and the control force versus the electric current in the electromagnet were derived using the equation of the electromagnetic theory. Numerical simulations under the control using the optimal regulator for the magnetically levitated boby were carried out. To verify the present theoretical results, experimantal results were also obtained.
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| 23.
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小島, 宏行 ; 田口, 和哉 ; 辻, 浩明
概要:
application/pdf<br />Journal Article<br />When an industrial robot with a power transmission mechanism such as a harmonic drive gear is operated, vibrations resulting from the torque ripple of the power transmission mechanism are
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frequently generated. However, few studies on robot vibration characteristics owing to torque ripples have been reported. In this paper, the vibrations of a horizontal two-link robot are investigated with consideration given to the torque ripple and the nonlinearity of the power transmission mechanism. In the numerical analysis, the torque characteristics are assumed to be the product of the nonlinear function of the torsional angle of the gear teeth and the torque ripple represented by means of the the Fourier series of the rotating angle of the input axis. Numerical simulation is carried out, and the effects of the torque ripple and the nonlinearity on the vibration characteristics of the robot are demonstrated. The experiment also shows that the torque ripple can cause a good deal of vibration.
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| 24.
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武田, 定彦 ; 長屋, 幸助 ; 永井, 健一 ; 井開, 重男
概要:
application/pdf<br />Journal Article<br />This paper presents theoretical and experimental results for the steady state response of a relaxation-suspension system considering the unsymmetrical damping force under periodic excitation.
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the unsymmetrical damping force has two different values in period of the stroke velocity. In the analysis, exact solutions are obtained by considering the continuity of the response at the boundary in which the damping force varies. Numerical calculations are carried out for various values of the ratio of the damping coefficient. It is found that the reference line of the vibration in the relaxation-suspension system maintains a constant value within the range of the high frequency ratio, while the reference line in the direct-suspension system varies proportionally to the change of frequency ratio. The experimental values agreed fairly well with the theoretical results.
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| 25.
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長屋, 幸助 ; 渡辺, 和秀 ; 塚原, 裕
概要:
application/pdf<br />Journal Article<br />Much resarch on the dynamic response of driven valve systems of internal combustion engines has been reported. However, the analytical model proposed in the previous reports constructed under
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the assumption that the valve did not separate from the rocker arm during the cam rotation. This model is applicable to the system with small rigidities. Recently, to have stable motion in high speed engines, the rigidity of the valve system increases, so that the previous model cannot be applied to the engines. This paper proposes a method for obtaining the jump and bounce phenomena of the valve system with large rigidities by considering the set force of the valve spring which gives large effects on the valve response. Numerical calculations have been carried out for one of the recest engines, and the experimental tests also have been performed to verify the present analysis.
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| 26.
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長屋, 幸助 ; 加藤, 宗一
概要:
application/pdf<br />Journal Article<br />This paper is concerned with a method for analyzing the dynamic response of a multispan beam on magnetic supports to an unsteady load decaying exponentially with time. The analysis assumes the
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nonlinear spring system as a group of segments of linear springs, and derives the expression for the nonlinear transient response by use of a method combining the Laplace transformation, Fourier series expansion and residue theorem. Numerical calculations have been carried out for some sample problems, and the effects of nonlinearity due to the magnetic supports have been clarified.
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| 27.
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長屋, 幸助 ; 中田, 雅之
概要:
application/pdf<br />Journal Article<br />This paper is concerned with a method for solving forced vibration problems of an arbitrarily shaped plate excited by a number of eccentric circular sinusoidal forces. The analytical solution for
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finding the displacements in the plate has been presented by use of the Fourier expansion collocation procedure. Numerical calculations have been carried out for four cases of circular, elliptical, square, and rectangular plates which are excited by one through four vibration forces. The effects of eccentricity and the size of circular forces on the vibration response have been clarified.
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| 28.
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長屋, 幸助 ; Poltorak, Krzysztof
概要:
application/pdf<br />Journal Article<br />The eigenvalue problem of Helmholtz's equation is of importance because various physical phenomena are governed by this equation. This paper presents a method for solving the boundary value
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problem governed by Helmholtz's equation haying a circular outer boundary and a number of eccentric circular inner boundaries. In this problem, it is difficult to satisfy the multiple connected boundary conditions. The present anlysis uses the point-matching approach for treating the inner boundary conditions, and presents the expression for finding the eigenvalues. Numerical calculations have been carried out for the system having one, two or four eccentrdc circular inner boundaries.
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| 29.
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長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper discusses transient stresses in a general shaped three dimensional curved rod with an arbitrary cross section subjected to general transient excitation. The paper gives and
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analytical method for finding normal and shear stresses in the rod by use of the transfer matrix, the Laplace transform, the Fourier expansion and the Fourier expansion collocation methods based on the there dimensional curved beam theory. As an application, this paper treats the coil spring of an arbitrary cross section, and proposes a rational coil spring having an oval cross section. It is clarified that the oval cross section coil with an appropriate aspect ration has various advantages as compared with the circular cross section spring.
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| 30.
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小島, 宏行
概要:
application/pdf<br />Journal Article<br />When an alternating electromagnetic force is applied to the mechanical vibration system, nonlinear forced vibrations such as superharmonic and subharmonic vibrations are generated owing to the
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nonlinearity of the electromagnetic force. In this report, the analytical method by the finite element method and the harmonic balance method is presented to investigate the nonlinear vibrations of a beam subjected to the alternating electromagnetic force. In the analysis, the equations of motion of the beam are obtained by the finite element method, and the nonlinear matrix equations which decide the force vibration amplitudes are derived in consideration of the second order superharmonic and the one-second order subharmonic by applying the harmonic balance method. Then, the nonlinear matrix equations are reduced, and three simultaneous equations are derived. Furthermore, the numerical results by use of the Newton-Rapson method agree well with the previous numerical results, and the present analytical method is confirmed.
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| 31.
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長屋, 幸助 ; 佐藤, 浩 ; 中村, 信章 ; 武田, 定彦 ; 永井, 健一 ; 井開, 重男 ; 孫, 健利
概要:
application/pdf<br />Journal Article<br />Thi paper describes a method of active vibration control for passing through critical speeds of a rotating shaft using electro-magnetic clutches. In this method the vibration of the shaft due to
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whirling is controlled by means of on and off electric current controls of the electro-magnetic clutches which support the shaft under the on control, The principle of this method is to change the eigen-frequencies of the shaft by adding or losing the supports during shaft rotation. To verify the present method, this paper provides a model of a rotating shaft system with an electro-magnetic clutch, and examines the results analytically and experimentally.
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| 32.
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長屋, 幸助 ; 後藤, 徹朗
概要:
application/pdf<br />Journal Article<br />This paper presents a method for analyzing three-dimensional curved rods of general shape without symmetric axes. In the analysis, the exact solutions of the equlibrium equations for three
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dimensional curved rods have been obtained first, then the transfer matrix has been derived based on the exact solution with consideration of inertia forces. The analytical equations for finding the eigenfrequencies and mode shapes have been given. Numerical calculations have been carried out for three dimensional circular, elliptical, and parabolic spiral rods of circular and square cross sections without symmetric axes.
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| 33.
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長屋, 幸助 ; 中田, 雅之 ; 増尾, 芳幸 ; 井開, 重男
概要:
application/pdf<br />Journal Article<br />This study proposes a new type of electromagnetic multiple disk brake for controlling the friction torque of the brake by using a rare earth magnet which generates very strong magnetic fields.
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This brake consists of a rare earth permanent magnet, an electric magnet and multiple friction disks. In this system, a control device such as a microcomputer generates an electric current in a coil of the electric magnet, and controls the friction torque of the brake. In the analysis the design formulae for the brake is first derived, based on the theory of electro-magnetic fields and the theory of tribology, then the transient friction torque is derived using the theories of Dynamics of Machinery and Automatic Control. To verify the present system and the analytical method, experimental tests have been performed for a model of the above-mentioned brake.
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| 34.
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永井, 健一 ; 長屋, 幸助 ; 武田, 定彦 ; 荒井, 徳幸
概要:
application/pdf<br />Journal Article<br />The free bending vibrations of beams with a concentrated mass subjected to axial forces caused by axial acceleration are analyzed by the Galerkin method, introducing the mode shape functions which
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are the sum of the products of the finite power series and the trigonometrical function. This analytical method makes it easy to construct the equations of motion in each boundary condition only by exchanging the coefficients of the finite power series. Numerical calculations are carried out under four sets of boundary conditions combined with simply supported and clamped edges. The natural frequencies and the corresponding modes of vibration are determined under both various locations of the concentrated mass and axial forces. it is found that the transverse inertia force and the axial force, due to the concentrated mass, have significant effects on the change of the natural frequencies for beams. Furthermore the distinction of boundary conditions gives predominant influence to the variation of natural frequencies.
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| 35.
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長屋, 幸助
概要:
application/pdf<br />Journal Article<br />An analytical method and a result for obtaining dynamic stresses in the valve-spring of a driven valve system of internal combustion engines are presented with a consideration of the end
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effects. To treat the complex dynamic behavior due to cam rotation with complex profile, this paper applies a combination method of the transfer matrix, the Laplace transform and the Fourier series expansion procedures. Numerical calculations have been carried out for a sample case of general valve-springs, and the numerical results for the dynamic stresses have been obtained in the case of a spring excited by the driven valve system.
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| 36.
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長屋, 幸助
概要:
application/pdf<br />Journal Article<br />This paper presents a method for solving the dynamic response problems of a driven valve system of internal combustion engines. In this system there is a hysteresis behavior between the
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restoring force and the deflection for the locker arm. To treat this nonlinearity, the rigidity of each section is assumed to be the one of a partly linear spring. For the valve trains, the cam profile is complex in general. For treating a general cam profile, this paper applies a combination method of the Fourier expansion and the Laplace transform methods given by the author. Numerical calculations have been carried out for a sample problem of high speed driven valve trains, and the jump and the bounce phenomena are discussed in detail.
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| 37.
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長屋, 幸助 ; 大月, 和也
概要:
application/pdf<br />Journal Article<br />This paper discusses a nonlinear transient response of a floating body supported by a magnetic force which is generated between two magnets of the same poles. In this system there are two
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kinds of nonlinearity, one of which is due to the restoring force between maguets and the other is due to the load which is a function of the displacement of the body. To treat these nonlinearities the restoring force is assumed to be a partly linear spring and the load is treated by the successive iteration method. This paper also considers the general transient load, and applies a combination method of the Fourier expansion and the Laplace transform method given by Nagaya. Numerical calculations have been carried out for one of the models. To verify the present analysis, experimental tests have also been performed for the same model treated in the numerical calculation.
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| 38.
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小島, 宏行 ; 根津, 紀久雄 ; 黒沢, 勝彦
概要:
application/pdf<br />Journal Article<br />Dynamic characteristics of a beam structure with an active electromagnetic damper are investigated by the use of the finite element method and the Laplace transformation. A shock pulse is
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applied to a beam subjected to a camping force by the active electromagnetic damper. In the analysis, first, the governing matrix equations of the coupling system consisting of the beam and the active electromagnetic damper are obtained by the use of the finite element method. Then, the governing matrix equations are transformed into the complex domain by the Laplace transformation method, and the transient vibration responses of the coupling system are derived directly by the application of the residue theorem. Furthermore, numerical calculations are carried out for an exponentially decaying pulse and a half sinus one, and the numerical results agree well with the previous experimental ones.
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| 39.
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長屋, 幸助 ; 中田, 貴隆 ; 武田, 定彦
概要:
application/pdf<br />Journal Article<br />This paper deals with a method for solving dynamic stress problems of a non-cylindrical viscoelastic coil spring subjected to base excitations. The analysis considers the effects of ends of the
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coil, and applies the three dimensional curved beam theory for obtaining the exact solution of the element of the coil. The resultant forces and the resultant moments in the vibrant coil are decided by means of the transfer matrix method for an arbitrary shape. Both the shear and the normal stresses are obtained by use of the curved beam theory as just mentioned. Numerical calculations have been carried out for two cases of a barrel spring and a hyperboloidal spring.
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| 40.
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小島, 宏行 ; 白石, 秀雄 ; 長屋, 幸助
概要:
application/pdf<br />Journal Article<br />In this report, the transient vibrations of a beam mass system subjected to nonlinear electromagnetic force are investigated theoretically and experimentally in consideration of both the
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nonlinearity of the electromagnetic force and the inductance of a electromagnet. The beam is fixed at one end, and the mass is attached to another end. The electromagnetic force produced by the elctromagnet acts on the mass. The electromagnet is excited by sinusoidal waves, rectangular waves and rectangular pulse voltages by using a micro computer. In the analysis, the electromagnetic force is approximated by using a series of rectangular pulses, and the lateral vibrations of the beam are obtained by adding the individual responses due to each rectangular pulse. The response solution of the governing partial equation of the beam mass system is derived by the Laplace transformation method. The numerical results agree well with the experimenatal ones.
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| 41.
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長屋, 幸助 ; 小島, 宏行 ; 岩田, 浩明 ; 伊藤, 美津夫 ; 太田, 幸一
概要:
application/pdf<br />Journal Article<br />磁気ダンパとサーボモータを用いた,コンピュータによるパルス信号制御の開ループ位置決め系を提示し,この系の妥当性を検討した.解析では軸振動の影響を考慮し,ばね
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と連続体についての両結果を誘導して両者の比較検討を行い,通常の制御速度でのばね系による解析の妥当性を明らかにした.また軸を剛体とした場合の結果を示して軸振動の影響を検討した.さらに軸の強度設計の観点から,軸のねじりモーメントを与える式をも示した.
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| 42.
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小島, 宏行 ; 新山, 文彦 ; 長屋, 幸助 ; 永井, 克巳
概要:
application/pdf<br />Journal Article<br />本報は, 衝撃力が作用するはり状構造物の振動制御の実験を, 前報で試作した速度フィードバック形電磁ダンパを用いて行うとともに, はり形の振動変位ならびに制御
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系の電流の衝撃応答解を, ラプラス変換法およびベルヌーイ・オイラーのはり理論を用いて厳密に導いたものである. なお衝撃力として, マイクロコンピュータと電動リニアアクチュエータによる電磁力を用いた. さらに振動制御の効果や安定性などについて詳細に調べた.
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| 43.
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長屋, 幸助 ; 池田, 真治
概要:
application/pdf<br />Journal Article<br />This paper discusses the bending vibration characteristics of a rotating shaft of a motor, with consideration of the electromagnetic sucking force which acts on a rotor, caused by the narrow
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electromagnetic field between a stator and the rotor. The dynamic response of the motor under the action of the whirling load of the shaft has been analyzed systematically by considering both the translational and rotary motions of the motor. In the analysis, the transfer matrix method is utilized to obtain the response of the shaft. The equation of longitudinal vibrations of a viscoelastic body is applied to the analysis of the viscoelastic foundation under the assumption of the structural damping. Numerical calculations have been carried out for the critical speeds and the response of both the shafts and the motor.
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| 44.
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長屋, 幸助 ; 武田, 定彦 ; 中田, 貴隆
概要:
application/pdf<br />Journal Article<br />This paper is concerned with the method for analyzing the vibration of coil springs with arbitrary shape. In the analysis, the field transfer matrix is derived from the solution of the
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foundamental equation of the curved beam theory. The transfer matrix is given by combining this field transfer matrix and the point transfer matrix. The analysis derives the frequency equation which is applicable to the coil spring of general shape. Numerical calculations have been carried out for HYPERBOLOIDAL springs and barrel springs. Experimental tests are also carried out to verify the present theoretical results.
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| 45.
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白石, 明男 ; 山川, 出雲
概要:
application/pdf<br />Journal Article<br />This report presents the effect of Coulomb friction combined with viscous damping in the main system to which a viscous-damped dynamic vibration absorber is attached. The main mass is excited
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by a rotating unbalance, and in the analysis, a similar process is used to that explained in the previous report^<(3)>. Thus, the conclusions are : - (1) The numerical results of analytical solution coincide very well with those of digital simulation. (2) Coulomb friction coexisting with the viscous damping in the main system, with a dynamic vibration absorber tuned so as to suppress the resonant response of the system in considering only viscous damping, reduces the maximum amplitudes of the main mass. The features of two equi-height maximums in the resonance curve vanish. (3) By reason that conventional expressions for the optimum tuning of the absorber do not fit in this case, other new empirical formulae are recommended.
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