| Item type |
紀要論文 / Departmental Bulletin Paper(1) |
| 公開日 |
2015-03-26 |
| タイトル |
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タイトル |
Dynamical Stability of a Column under Periodic Longitudinal Forces. |
|
言語 |
en |
| 言語 |
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言語 |
eng |
| 資源タイプ |
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資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
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資源タイプ |
departmental bulletin paper |
| その他のタイトル |
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その他のタイトル |
縱の振動的力を受ける柱の力學的安定 |
| 著者 |
内田, 郁雄
妹澤, 克惟
UTIDA, Ikuo
SEZAWA, Katsutada
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| 出版者 |
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出版者 |
東京帝國大學航空研究所 |
| 出版者（英） |
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出版者 |
Aeronautical Research Institute, Tokyo Imperial University |
| 書誌情報 |
東京帝國大學航空研究所報告
en : Report of Aeronautical Research Institute, Tokyo Imperial University
巻 15,
号 193,
p. 138-183,
発行日 1940-08
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| 抄録 |
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内容記述タイプ |
Abstract |
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内容記述 |
柱が縱方向の振動的力を受ける場合の安定問題を實驗的及び數理的に研究した.研究の結果,この問題は柱の自由撓み振動の振動的安定と考へてもよいし,柱の縱の強制振動の共振と見てもよい事がわかつた.振動が不安定又は共振となる振動周期は無數にあり得るけれども,振動の形は常に節點のない基本型になる事がわかつた.この樣な振動の起るのは柱の自己振動數と強制力の振動數との比が1/2,2/2,3/2,4/2,5/2,6/2,.....となる場合である.しかしこの比が大きくなればなる程,不安定になるべき振動數の範圍(各不安定について振動數の範圍がある)が狹くなり,共振と考へるべき振幅が少くなることがわかつた.各不安定又は共振について,振動數を増加する段階に於ける振幅變化と振動數を減少する段階に於ける振幅變化とが同じでない事がわかつた.振動數を減少する場合には之を増加する場合の振幅よりも大きな振幅が殘り,或振動數まで下げたところで急に振幅が少くなつて振動數を増加するときのそれに等しくなる.振動數を増加する階梯に於て只今の大きな振幅を持たせるには特に人工的の衝撃を與へてやらねばならぬ.柱の端に餘り大きくない質量が置いてある場合には,今少しく複雜なる現象があるのである.不安定又は共振に相當する振動では大體に於て正弦形振動であるが,振動數の次數が高くなるにつれて少しづつ正弦から外れるやうになる.相隣れる不安定の中間の振動數では2つの不安定に於ける正弦振動が相重なる傾向にある.實驗的及數理的結果によれば,不安定又は共振の振幅は振動力の大さに關係する事がわかつた.この大さが餘り大きくないと,不安定も大振幅の共振も起らぬ事になる.之によつて,只今の現象は振動數からいふと共振の性質を帶びるし,振動力の大きさからいふと柱のへし折れに類する性質をもつ事がわかる. |
| 抄録（英） |
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内容記述タイプ |
Other |
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内容記述 |
The present problem deals with the vibrational condition of a column under periodic longitudinal forces. The problem was examined in two ways, namely, experimentally and mathematically. The result of investigation shows that the problem is dynamically that of instability in free transverse oscillation as well as that of resonance in forced longitudinal vibration. Although there is a number of frequencies at which the vibration becomes unstable or resonance-like, the mode of vibration of the column is of fundamental mode almost in any case, that is to say, the fundamental mode of vibration is excited by the periodic forces of different frequencies. The conditions in which the vibration in question occurs, are such that the ratios of the natural frequency to that of the exciting forces are 1/2, 2/2, 3/2, 4/2, 5/2, ... The greater the ratio under consideration, the smaller the resonance amplitude and, also, the range of instability. The condition in which the ratio becomes 1/2, corresponds to that called Melde's effect. At every resonance or unstable condition, the change of amplitude in the stage of raising frequency is not the same as that in the stage of decreasing frequency. In the stage of decreasing frequency the vibration amplitude augments increasingly for a relatively wide range until the limit is reached when the amplitude suddenly reduces to that taken in the stage of raising frequency. In order to get the condition corresponding to the stage of decreasing frequency even in the stage of increasing frequency, some artificial shock should be applied to the column. When there is a relatively small mass at an end of the column, there are some further complex relations between the vibration amplitude and the frequency. Although the periodic vibration of the column in the unstable or resonance condition is almost of sine form, the same form tends to change increasingly with increase in the order of resonances. It is likely that the wave form of the vibration of the column in the frequency intermediate between two neighbouring unstable conditions, contains both types of waves in these unstable conditions. Experimental as well mathematical results show that the resonance or instability condition depends on the magnitude of the vibrating forces applied. If the forces were not great, it would be impossible for the resonance or unstable condition to occur, from which it follows that the phenomena resemble those of resonance vibration with respect to the vibrational frequency and these of buckling with respect to the magnitude of the applied forces. |
| 書誌レコードID |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA00387631 |
| 資料番号 |
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内容記述タイプ |
Other |
|
内容記述 |
資料番号: SA4146974000 |
SA4146974.pdf (2.2 MB)
