巻号一覧
41 巻, 10 号
選択された号の論文の20件中1～20を表示しています
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庄司 光原稿種別: 本文
1985 年 41 巻 10 号 p. 663-666
発行日: 1985/10/01
公開日: 2017/06/02
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岸 憲史原稿種別: 本文
1985 年 41 巻 10 号 p. 667-676
発行日: 1985/10/01
公開日: 2017/06/02
ジャーナル フリーThis paper investigates the computation accuracy of the finite element analysis applied to the in-plane modes of a piezoelectric rectangular plate, and then gives the most appropriate shape of the element. Three types of subdivision elements are used in this study: a constant-strain triangular element (CTE), a first-order rectangular element (RE), and a linear-strain element (LTE). We propose a method to predict the error in calculating the eigen frequencies by only using finite element analyses, then apply it to calculate the errors in the eigen frequencies of various vibrational modes of a square plate and a 5:1 rectangular plate. It is found that this predicted error for a Lame mode of the square plate agrees with that obtained by the exact theory. It is also shown that the shape of the element which achieves the best accuracy for the large majority of modes is either the isosceles right triangle for CTE and LTE or the square for RE, under the conditions that a plate is subdivided into the same elemental shape and the total number of elements are kept approximately equal. Finally, two examples of the finite element analyses are worked out and compared with the experimental results.抄録全体を表示PDF形式でダウンロード (1065K) -
東 貞男, 打越 聰, 城戸 建一原稿種別: 本文
1985 年 41 巻 10 号 p. 677-683
発行日: 1985/10/01
公開日: 2017/06/02
ジャーナル フリーThe effects of the structure, the distribution of sensitivity and phase of each microphone unit and the dimensinonal errors on the performance of an arc-arrayed microphone system are theoretically investigated. The arc-arrayed microphone system is considered to be useful for detecting and investigating sound sources in the noise control engineering. The microphone system is composed of 101 miniature microphones arrayed on a circle at the interval of 2cm. The radius of the circle is 5m and the length of the array is 2m. First, the effect of the weighting function on the spatial distribution of sensitivity is investigated with uniform weighting, Hamming weighting, the composite weighting with the former two and Blackman weighting. The Hamming weighting is considered to be the best in the view point of practical use. Next, the effects of the distribution of sensitivity of microphone units on the spatial distribution of system sensitivity are investigated. The deviation of sensitivity in magnitude does not affect so much on the peaks of the side robes but the deviation in phase does. The deviation of the sensitivity is measured for 150 miniature microphone. The standard deviation in sensitivity is about 1 dB in magnitude and that in phase is negligible. Comparing the result of measurement with the theoretical investigation, it is concluded that the commercialized miniature microphones can be used for the unit of the arc-arrayed microphone system. The effects of the dimensional accuracy of the array are then investigated. The deviation of the distance between every microphone unit gives little effect on the shape of the side robe. But, the accuracy is strictly required in the distance from the focul point to every microphone unit, especially in the high frequency range. To suppress the magnitude of side robes less than -40 dB comparing with that of the main robe, the deviation should be 1/40 of the wave length.抄録全体を表示PDF形式でダウンロード (917K) -
久野 和宏, 今井 兼範原稿種別: 本文
1985 年 41 巻 10 号 p. 684-689
発行日: 1985/10/01
公開日: 2017/06/02
ジャーナル フリーBoth the image theory and the classical theory of reverberation are practically used in room acoustics to predict sound fields in enclosures. In the present paper, we show that the result of image theory corresponds to the Sabine's result provided that discrete distribution of real and image sources is smoothed appropriately. This idea is expanded to sound field in tunnel or corridor (i. e. , two-dimensional enclosure) as well as in space between two parallel walls (i. e. , one-dimensional enclosure), for predicting them. Then, we compare the reverberant characteristics among three types of sound fields mentioned above. It is found that especially in early decay process the sound fields in one- and two-dimensional enclosures diminish much more rapidly than those in rooms. Furthermore, it is theoretically demonstrated that the reverberant fields in one- and two-dimensional enclosures yield convexly curved decay curves.抄録全体を表示PDF形式でダウンロード (706K) -
太田 光雄, 高桑 誠明, 宮田 繁春原稿種別: 本文
1985 年 41 巻 10 号 p. 690-699
発行日: 1985/10/01
公開日: 2017/06/02
ジャーナル フリーAs is well-known, in the measurement of low frequency sound, a main spectrum component of the wind noise exists almost within the same frequency bands as the low frequency sound. Accordingly, it is essentially difficult to eliminate the effect of wind noise by use of the analog filter based on the usual electrical circuit. Sometimes, this effect of wind noise can be partly decreased by using the windscreen or putting the microphone near the ground surface. However, they are not a drastic countermeasure. From the above point of view, in this paper, two kinds of typical countermeasure methods which are in striking contrast in removing the above wind noise are proposed, especially by focussing the central point of present study on its principle of method and practical usefulness. Concretely, two different measurement methods based on the principle of Bayes' filter and synchronous detection are employed in the low frequency sound. Both methods use basically the information of linear correlation between the actually observed value and the buried signal in the countermeasure of wind noise, and their practical estimation algorithms are explicitly proposed corresponding to the above two contrastive methods. Finally, the effectiveness of these two estimation methods of removing the wind noise is experimentally confirmed too by applying them to the actual data observed in a free sound field.抄録全体を表示PDF形式でダウンロード (1293K) -
山口 静馬, 加藤 裕一, 太田 光雄原稿種別: 本文
1985 年 41 巻 10 号 p. 700-702
発行日: 1985/10/01
公開日: 2017/06/02
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長友 宗重原稿種別: 本文
1985 年 41 巻 10 号 p. 703-
発行日: 1985/10/01
公開日: 2017/06/02
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飯田 茂隆原稿種別: 本文
1985 年 41 巻 10 号 p. 704-708
発行日: 1985/10/01
公開日: 2017/06/02
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筧 一彦原稿種別: 本文
1985 年 41 巻 10 号 p. 709-714
発行日: 1985/10/01
公開日: 2017/06/02
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上村 幸雄原稿種別: 本文
1985 年 41 巻 10 号 p. 715-718
発行日: 1985/10/01
公開日: 2017/06/02
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竹内 義夫原稿種別: 本文
1985 年 41 巻 10 号 p. 719-722
発行日: 1985/10/01
公開日: 2017/06/02
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板橋 秀一原稿種別: 本文
1985 年 41 巻 10 号 p. 723-726
発行日: 1985/10/01
公開日: 2017/06/02
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中田 和男原稿種別: 本文
1985 年 41 巻 10 号 p. 727-728
発行日: 1985/10/01
公開日: 2017/06/02
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難波 精一郎原稿種別: 本文
1985 年 41 巻 10 号 p. 729-730
発行日: 1985/10/01
公開日: 2017/06/02
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永田 穂原稿種別: 本文
1985 年 41 巻 10 号 p. 731-
発行日: 1985/10/01
公開日: 2017/06/02
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齋藤 收三原稿種別: 本文
1985 年 41 巻 10 号 p. 732-
発行日: 1985/10/01
公開日: 2017/06/02
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比企 静雄原稿種別: 本文
1985 年 41 巻 10 号 p. 733-738
発行日: 1985/10/01
公開日: 2017/06/02
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脇田 壽原稿種別: 本文
1985 年 41 巻 10 号 p. 739-744
発行日: 1985/10/01
公開日: 2017/06/02
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著者:Schroeder M.R., 伊達 玄原稿種別: 本文
1985 年 41 巻 10 号 p. 745-
発行日: 1985/10/01
公開日: 2017/06/02
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著者:城戸 健一, 青島 伸治原稿種別: 本文
1985 年 41 巻 10 号 p. 745-
発行日: 1985/10/01
公開日: 2017/06/02
ジャーナル フリーPDF形式でダウンロード (205K)
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