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永井, 健一 ; 荒井, 徳幸 ; 長屋, 幸助 ; 武田, 定彦
概要:
application/pdf<br />Journal Article<br />An analytical method is presented for free flexural vibrations of a cantilevered beam with a concentrated mass, introducing the new mode shape function to the Galerkin procedure. The mode
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shape function is expressed with the sum of the product of the trigonometrical function and the finite power series truncated with the fourth order. The trigonometrical function expresses the form of the higher mode of vibration. The coefficients of the power series are determined by solving the homogeneous equations for the boundary conditions of the beam. Applying the Galerkin method, the sets of differential equation in a time function are reduced. It is found that this method gives good accuracy to the natural frequencies and the natural modes of vibration within the limited number of terms for unknown time functions.
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武田, 定彦 ; 長屋, 幸助 ; 永井, 健一 ; 井開, 重男
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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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永井, 健一 ; 長屋, 幸助 ; 武田, 定彦 ; 中村, 欣明
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application/pdf<br />Journal Article<br />Analytical results are presented for nonlinear vibrations of a stretched string connected with a laterally movable end mass at one end. Applying the modified Galerkin method to the basic
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equations, a set of ordinary differential equations with cubic nonlinearity is obtained. The steady-state response is determined by the harmonic balance method. Numerical calculations are carried out for the various values for the end mass to the string and the geometry of the string. It is found that if the mass of the end mass increases to greater than that of the string, the resonant response in the first mode of vibration can be treated as a linear vibration up to a sufficiently large amplitude. However, the resonant curves in the higher mode of vibration show responses with a strong nonlinearity within a small amplitude. The increment of the cross section area of the string also gives a strong nonlinearity to the response in every mode of vibration.
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長屋, 幸助 ; 武田, 定彦 ; 井開, 重男 ; 永井, 健一 ; 松本, 康臣 ; 塩野, 二朗
概要:
application/pdf<br />Journal Article<br />This paper proposes an active control damper using an electromagnetic fluid, and presents an expression for obtaining the damping coefficient of the damper. The damping coefficient has been obtained
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by using the solution of the equation for the electromagnetic fluid which includes both Navier-Stokes' equation and Maxwell's equation. Numerical calculations have been carried out for some sample problems, and the effects of sizes of the damper and the magnetic flux density on the damping coefficients have been clarified.
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長屋, 幸助 ; 吉田, 彬 ; 井開, 重男 ; 山本, 哲也 ; 横山, 信行 ; 永井, 健一
概要:
application/pdf<br />Journal Article<br />This paper is concerned with a method for measuring masses of the magnetic particles in a fluid such as a magnetic fluid. Two methods are proposed, one of which is the phase difference procedure
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by use of a laser, and the other is the nuclear magnetic resonance (NMR) procedure. Experimental tests have been carried out to find masses of the magnetic particles in the magnetic fluid with various densities by using the methods mentioned above. It is clarified that the present methods are applicable to measure the masses in a fluid, including a few particles.
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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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長屋, 幸助 ; 加藤, 宗一
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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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永井, 健一 ; 笹井, 重俊 ; 長屋, 幸助 ; 武田, 定彦 ; 内山, 茂
概要:
application/pdf<br />Journal Article<br />This paper presents a method for the error compensation of measuring data in a two-dimensional length measuring device from lack of sufficient stiffness. Introducing the mode shape function
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which is expressed with the product of the finite power series truncated with fourth order and the trigonometric function to the least square approximation. Applying the method to the test device, the effects of compensation are clarified. It is found that this method gives good results to improve the measuring accuracy with the limited number of terms for unknown coefficients, compared with the approach of the Fourier series.
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長屋, 幸助 ; 中田, 雅之
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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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長屋, 幸助 ; Poltorak, Krzysztof
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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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