The first ten natural frequencies, damping ratios and mode shapes of the dam were measured through steady forced vibration test using multiple vibrators.

用多台起振机进行稳态强迫振动试验，测定了该坝前十阶自振频率、阻尼和振型。

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Compared with forced vibration tests, the ambient vibration test is more convenient and it has enough accuracy for the small amplitude response characteristics.

与强迫振动试验相比，环境振动试验比较简单、方便，所确定出的小振幅水平下的木塔结构动力特性具有足够的精度。

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Forced surge test may cause over vibration and damage to the compressor rotor during the compressor characteristics test.

压气机特性试验中逼喘是必须进行的，但它常常造成压气机转子振动过大，并对压气机转子造成一定的损伤。

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