著者

長江 信顕 後藤 知伸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集C編 (ISSN:18848354)

巻号頁・発行日

vol.79, no.803, pp.2314-2328, 2013 (Released:2013-07-25)

参考文献数

10

被引用文献数

1

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The predictive accuracy for the dynamic behaviour of a rotor under conditions of high-speed spinning depends on the accuracy of the numerical model of the rotor, the dynamic characteristics of the bearings and/or the seals, and the external force. In order to improve the accuracy of the numerical model, we propose a method to identify all characteristic matrices in the vibration equation of a rotor based on the information on rigid and elastic properties which can be obtained by a vibration test without spinning. The rotor is assumed to be composed of a shaft which can be modeled as beam elements and rigid discs. The proposed method can be applied for model reduction in which the reduced number of beam elements is feasible to calculate the dynamic behaviour of the rotor.

著者

西村 正治 糟谷 秀太郎 後藤 知伸

出版者

The Japan Society of Mechanical Engineers

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.78, no.789, pp.949-953, 2012

被引用文献数

1

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Light wall structures with high sound insulation performance are desired to be developed for houses and fuselage of vehicles. In this paper, a new light sound insulation structure is proposed. It is constructed with light inflated membrane bound by hard wire nets. By impedance tube tests, the proposed structures were proved to have not only high but also adjustable sound insulation performance by tuning the inside air pressure, which means stiffening the membranes. This structure can also construct a light sound insulation panel with high sound insulation performance by being inserted between light double walls.

著者

西村 正治 後藤 知伸 松岡 裕和

出版者

一般社団法人日本機械学会

雑誌

環境工学総合シンポジウム講演論文集

巻号頁・発行日

vol.2003, no.13, pp.91-94, 2003-06-24

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We, human being, hear 'twitter of birds', 'stream sound' etc. as comfortable sound. On the other hand, we hear 'sound scratching window', 'sound scrubbing styrene foam' etc. as uncomfortable noise. What is the difference between them? In this paper, the uncomfortable rates of 16 daily hearing sounds were evaluated at first, using method of paired comparison. Then, those sounds were analyzed by the human auditory model and wavelet analysis in order to find out causes of discomfort. Such characteristics of comfort and discomfort were found out that the former has calm rising up and down and the later has steep rising up and down, and that the former has sinusoidal vibratos in high frequency region and the later has irregular ones. But the auditory indexes which can evaluate the noisiness of machines were proved hardly to have correlation with uncomfortable rate.