FFT Applications

FFT         Vibration analysis

V-1-2      Measuring natural vibration frequency by sine sweep using internal signal from an exciter controller

  • Sweep excitation is one of the methods to measure natural frequency of parts etc. The sweep averaging function of the DS-5000 O-solution calculates the frequency response function of the vibration on the excitation table and acceleration of measurement object by sine sweep.
  • For instance, a test is performed with the controller of the vibration exciter set to 10 Hz to 200 Hz sine sweep and the acceleration of 30 m/s2 and then the frequency response function of vibration of the excitation table and acceleration of the part is measured using the sine sweep averaging function in sync with the internal signal of the DS-5000 O-Solution.
  • The sweep time must be taken long time (approx. from several minutes to several tens of minutes). Because a measurement will take long time in low frequency range, and it needs to minimize the frequency variation since excitation frequency of vibration exciter and sampling frequency of the DS-5000 O-Solution are measured asynchronously.
  • 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 enables display and evaluation of velocity/force (mobility), displacement/force (compliance), force/acceleration (dynamic mass), force/velocity (mechanical impedance), force / displacement (dynamic rigidity).

Product list

  Model Product name Remarks Qty
1 O-Solution DS-5000 6ch 40 kHz FFT set DS-5100 Main unit
DS-0526 6ch 40 kHz Input unit
OS-5100 O-Solution Platform
OS-0522 FFT Analysis function
OS-0512 Hardware Connection function 		1
2 NP-3211 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) 2
3 NP-0020 Signal cable extension adapter The adapter for signal cable extension (between the NP-0153 and the cable for the NP-3211). 2
4 NP-0153A Signal cable for the NP-0020 5 m, -25 to +160˚C 2
5 NP-0021 Miniature/BNC conversion connector Converts the NP-0153 signal cable terminal to BNC connector and input to the DS-5000 O-Solution BNC connector. 2

Remarks
The DS-5000 series needs a PC separately.
The DS-5000 series data stations "FFT Tracking Set", "FFT Octave Set", and CF-9200A / 9400 can also be used as analyzers.





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