FFT V-1-1 |
Measuring natural vibration frequency and
damping ratio by hammering test |
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- This example shows how to measure natural vibration
frequency and damping ratio etc. Suspend a measurement
object in a free vibration (or place it on something
soft) and perform hammering test by the GK-3100 Impulse
hammer. And then detect the free damping vibration by an
accelerometer. The DS-5000 series calculates the
frequency response function of acceleration (A) and
hitting force (F) by applying them to the following
calculation, and obtains the resonant frequency at the
peak of (A) / (F). (In this example, the peak value of
(A)/(F) equals to the resonant frequency, natural
vibration.)
- Frequency response function =
Acceleration (A) / Hitting force by the GK-3100 (F) (Accelerance
< Inertance >)
- You can see several peak values depending on a shape
of a measurement object. Damping ratio also can be
calculated by using half-power bandwidth method.
Moreover, integrating function of the DS-5000 series
enables display and evaluation of velocity/power
(mobility), displacement/force (compliance),
force/acceleration (dynamic mass), force/velocity
(mechanical impedance) or force/displacement (dynamic
rigidity).
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Model |
Product name |
Remarks |
1 |
DS-5000 O-Solution |
3ch 40 kHz FFT set |
DS-5100 メインユニット
DS-0523 3ch 40 kHz 入力ユニット
OS-5100 プラットフォーム
OS-0522 FFT解析機能
OS-0512 ハードウェア接続機能
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2 |
GK-3100 |
Impulse force hammer |
Frequency range:: up to 8 kHz, resonance
frequency: 31 kHz, hammer cable (3 m) & signal
output cable (0.9 m) (included) |
3 |
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Accelerometer with built-in preamplifier |
Ultra compact, lightweight (0.5 g), frequency
range: 0.3 Hz to 20 kHz ±3dB, signal cable (3 m)
(included) |
4 |
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Signal cable extension adapter |
The adapter for signal cable extension (between
the NP-0153 and the cable for the NP-3211). |
5 |
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Signal cable for the NP-0020 |
5 m, -25 to +160˚C |
6 |
NP-0021 |
Miniature/BNC conversion connector |
Converts the NP-0153 signal cable terminal to
BNC connector and input to the DS-5000 series
BNC connector. |
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Remarks
The DS-5000 series needs a PC separately.
The DS-5000 series data stations "FFT Tracking Set", "FFT Octave Set", and CF-9200 / 9400 can also be used as analyzers. |
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