| 含45度斜裂纹圆柱薄壳动态特性试验研究 |
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| 引用本文： | 许德刚;许俊萍;申道明;沈亚鹏.含45度斜裂纹圆柱薄壳动态特性试验研究[J].力学与实践,2006,28(1). |
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| 作者姓名： | 许德刚;许俊萍;申道明;沈亚鹏 |
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| 作者单位： | 郑州大学工学院工程力学系
郑州大学工学院工程力学系450002 郑州大学工学院工程力学系 |
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| 摘 要： | 测量了含45度斜裂纹圆柱薄壳的固有频率并拍摄了相应的激光全息振型图. 实验
表明斜裂纹比轴向和环向裂纹对壳体动态特性的影响更大，致使振型图发生了严重
畸变而显得相当复杂，利用传统思路难以找到裂纹长度对壳体动态特性的影响规律. 为此，
把裂纹周围的振动看作为一种独立的局部振动，从而把含斜裂纹壳体的各种复杂振型划
分为3类：纯局部振动振型、纯原振动振型、局部振动和原振动耦合振型. 其中前两种振型
的固有频率皆随裂纹的加长而降低，但对于耦合振型有时会出现``随裂纹加长频率反而升高
的现象'，这是由于把壳体原振动的频率和局部振动的频率相混淆而产生的错觉.
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| 关 键 词： | 斜裂纹 圆柱薄壳 动态特性 |
| 收稿时间： | 2005-1-17 |
EXPERIMENTAL STUDY ON VIBRATION CHRARCTERISTICS OF A CYLINDRICAL SHELL WITH A 45circ OBLIQUE CRACK |
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| Abstract: | The resonant frequencies and corresponding mode shapes of
steel thin-wall cylinder shell samples each containing an oblique
crack are obtained by a laser holographic interferometry method.
It is shown that the oblique cracks have a great
effect upon the vibration characteristics of the shells, with the mode shapes of
the shell being changed very much and looking very complicated. A kind of
vibration appeared only in the local area round the crack which is
called the partial vibration by this paper is discovered. The partial
vibration, which is responsible for the complicated
mode shapes, has resonant frequencies and
modes of vibration of its own. The vibration appeared in the entire shell is
called the original whole vibration. In a similar way, the original whole
vibration has the resonant frequencies and modes of vibration of its own.
When the resonant frequencies of the partial vibration close to that of the
original whole vibration, the two kinds of vibrations will come together. So
there are three kinds of vibration mode shapes: pure partial vibration mode
shapes, pure original whole vibration mode shapes and the intercoupling
vibration mode shapes in which partial vibration and original vibration
interact with each other. The longer the crack is, the lower the resonant
frequencies of the pure partial vibration and pure original whole vibration
are, but the resonant frequencies of the intercoupling vibration
occasionally
shows an inverse tendency, which is a phenomenon which may be confused
with two kinds of the resonant frequencies. |
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| Keywords: | oblique crack cylindrical shell vibration characteristics |
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