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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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| 2.
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王, 建春 ; 長屋, 幸助 ; 横田, 正二
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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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| 3.
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長屋, 幸助 ; 横田, 勇
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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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王, 建春 ; 長屋, 幸助 ; 横田, 正二
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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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長屋, 幸助 ; 関口, 肇
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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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長屋, 幸助 ; 山本, 哲也
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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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| 7.
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長屋, 幸助 ; 荒井, 徳幸
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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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長屋, 幸助 ; 渡辺, 和秀 ; 塚原, 裕
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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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| 9.
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長屋, 幸助
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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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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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