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Volume 52, Issue 478
Displaying 1-11 of 11 articles from this issue
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Junichi MITSUI1986 Volume 52 Issue 478 Pages 1727-1733
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSDownload PDF (711K) -
Takuya YOSHIMURA, Akio NAGAMATSU1986 Volume 52 Issue 478 Pages 1734-1741
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSMany kinds of curve fit techniques have been developed for estimation of the modal parameters of a mechanical structure, using the theory of modal analysis. As one of the most popular curve fit techniques which correspond to multiple input vibration test, the Vold in time domain method (Poly -reference) is known and used extensively. In this paper, a new method which is made from improving the Vold in time domain is proposed to obtain global modal parameters. The feature of this method is as follows. All the residue and the residual compliance is obtained at the same time by referring to all the transfer functions making use of eigen value and eigen vector, which is determined by Poly- reference method. By using this method, modal parameters of the fly wheel of an automobile are identified. Comparing this new method with former methods, the validity of the new method is confirmed.View full abstractDownload PDF (841K) -
Masaaki OOKUMA, Akio NAGAMATSU1986 Volume 52 Issue 478 Pages 1742-1749
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSThe authors propose a new method for identifying the characteristic matrices (the mass, the damping and the stiffness matrices) in this paper. The authors proposed a method of the identification in the first report before. But accurate characteristic matrices cannot be identified by the method when some errors are included in the transfer function used as the input data. Some errors are always included in the actual experimental data. Then, the theory of the identification with these actual experimental data is proposed by statistical consideration. In the new method, it is assumed that the error in the input data is normal distributive. Two numerical examples are shown in order to find that the new method can identify the accurate characteristic matrices with the input data (transfer function) which includes normal distributive error.View full abstractDownload PDF (871K) -
Hideyuki TAMURA, Yoshiaki MATSUDA1986 Volume 52 Issue 478 Pages 1750-1757
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSExact solutions of the autonomous Duffing equation including the so-called bistable spring system, are obtained in the Fourier expansion by using elliptic functions. The characteristic parameter J in the Fourier coefficients as well as the governing parameter m (or the complementary parameter m1) of the complete elliptic integral of the first kind, K(m), must be determined to satisfy conditions which arise due to the situation of the system and the non-dimensional natural frequency ν. In this paper three algorithms are established to compute the parameter m or ml exactly by a trial method, and also three approximate formulae to express J are proposed. The solutions are classified as five cases according to the characteristics of the spring system and the type of the wave form of the vibration. The frequency responses and some salient features of the solutions are examined and illustrated generally. The numerical results of J(ν) are shown in tabular form, the relative accuracy of which is about 10-4.View full abstractDownload PDF (844K) -
Shiro KOYANAGI1986 Volume 52 Issue 478 Pages 1758-1763
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSAs the air springs of a railway vehicle work not only to reduce the vertical vibration of the car body, but also to reduce both lateral vibration and roll, the optimum design of an air spring system should be consistent in these three directions. This paper deals with the method for selecting such values as air spring lateral rigidity, and the damping coefficient of the lateral damper optimum for the reduction of both lateral vibration and roll of the car body. This is under the premise that the oriffice damping coefficient of the air spring is chosen as optimum for the vertical vibration isolation by means of already established method. Also described is the method for determining the car body roll center height in case damping is present.View full abstractDownload PDF (618K) -
Yukio ISHIDA, Takashi IKEDA, Toshio YAMAMOTO1986 Volume 52 Issue 478 Pages 1764-1771
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSThis paper deals with the transient vibration of a rotating shaft with nonlinear spring characteristics during constant acceleration passing through a major critical speed. In a theoretical analysis, we solve the equation of motion numerically and discuss this phenomenon paying attention to nonlinear components represented by the polar coordinates. As a result, it is clarified that, when the angular acceleration λ increases, the maximum amplitude of the shaft decreases gradually for a small value of λ and extremely at a certain value of λ=λ0. This characteristic is different from that of a linear system, where the maximum amplitude decreases markedly in the range of small angular acceleration. We ascertained these phenomena in experiments. Generally speaking, it is more difficult to pass through a critical speed in a nonlinear system than in a linear system.View full abstractDownload PDF (909K) -
Kosuke NAGAYA, Tetsuro GOTO, Toyonori SASAKI, Sigeo IKAI1986 Volume 52 Issue 478 Pages 1772-1779
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSThis paper is concerned with a method for obtainning stresses in a rod of arbitrary cross-section subjected to combined loads of bendings, shearings and torsions which are the complicated functions of time. In the first step the analysis derives the bending moment, shearing force and torsional moment by use of a combination methods of the Laplace transformation and Fourier series expansion. The transient stresses are obtained based on the two dimensional theory of elasticity, but in which the Fourier expansion collocation procedure is applied to deal with the complex boundary shape of the cross section. To discuss the validity of this analysis, experimental tests are also carried out for an oval rod subjected to the three combined transient loads.View full abstractDownload PDF (838K) -
Masao NAGAI1986 Volume 52 Issue 478 Pages 1780-1786
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSIt is essential to actively control a magnetic suspension system, because it is physically unstable without any control. Self-excited vibration of a guideway is liable to take place when the magnetic suspension control is designed without regarding guideway flexibility, because of the interaction between the electromagnet and the guideway. In this paper, the reason for the self-excited vibration is analytically investigated, and then a design method is proposed to realize the suspension system, which is stable on a flexible guideway, and is low-sensitive to the condition of the guideway's flexibility.View full abstractDownload PDF (721K) -
Takayuki KOIZUMI, Yoichi ANDO1986 Volume 52 Issue 478 Pages 1787-1792
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSThis paper proposes a method to estimate the radiational sound field from circular pipe structures which have vibration surface. Laplace transform and the Wiener-Hopf technique are used to analyze the sound propagation and radiation. After this analytical formulation, a computer simulation algorithm has been derived as a form of matrix equations. Experimental investigation has also been performed using model acoustic tubes to verify analytical results. Sufficient agreement has been found between the numerical calculation and the measured response, and this concludes that the method proposed here can be practically applied to estimate the acoustic behavior of some machine components, as mentioned above.View full abstractDownload PDF (589K) -
Keiichiro MIZUNO, Hisayoshi SEKIGUCHI, Kazuyoshi IIDA1986 Volume 52 Issue 478 Pages 1793-1797
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSThe principle of the noise control device was described in the 1st report and the fundamental design method of the device was explained in the 2nd and 3rd reports. It is known from these studies that the acoustic design of the pipes composing the device is very important for studying the noise reduction region produced by the device ; and each pipe of the device has frequency selectivity. Therefore, it is necessary to study how the noise reduction region depends on a frequency, and how each pipe of the device contributes to the noise reduction region. These results are described in this paper.View full abstractDownload PDF (828K) -
Hisashi TAMURA1986 Volume 52 Issue 478 Pages 1798-1805
Published: June 25, 1986
Released on J-STAGE: February 21, 2008
JOURNAL FREE ACCESSA method of inspecting a spiral bevel gear is newly proposed. The tooth surfaces are measured using a three-coordinate measuring machine and ""the most probable tooth surface"" is determined from the measured data by the method of least squares. The equation of the determined surface involves two variables and some constants which correspond to the machine setting. Unavoidable errors in the machine setting cause slight deviations of the constants from the design values. The corrective gear cutting can be carried out using these values of deviation. This is the aim and end of this study.View full abstractDownload PDF (784K)
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