Contents
What does FFT mean in vibration?
fast Fourier transform
Fourier Analysis In engineering, the frequency domain is the usual domain for analysis. For continuous data, engineers use the Fourier transform to project the time domain data into the frequency domain. To do so, the fast Fourier transform (FFT) uses sine or cosine waves of varying frequency, amplitude, and phase.
What is main purpose of vibration analysis condition?
Vibration analysis is a process that monitors the levels and patterns of vibration signals within a component, machinery or structure, to detect abnormal vibration events and to evaluate the overall condition of the test object.
Why vibration analysis is suitable for diagnostic?
Therefore, monitoring the vibration characteristics of a machine can provide the information of its health condition, and this piece of information can be used to detect problems that might be incipient or developing.
What is the limit to a human body against vibration?
A daily exposure limit value of 1.15 m/s2 (or, at the choice of the individual EU Member State, a vibration dose value of 21 m/s)
How are FFT results used in vibration analysis?
So the FFT results should show you the amplitude versus frequency response (similar to the graph shown in the link), from which you can obtain the natural frequency and damping coefficient of your system. But it should be cautioned that vibration analysis is a complex and wide-ranging field.
How is the amplitude spectrum of FFT calculated?
The FFT function computes the complex DFT and the hence the results in a sequence of complex numbers of form. The amplitude spectrum is obtained For obtaining a double-sided plot, the ordered frequency axis (result of fftshift) is computed based on the sampling frequency and the amplitude spectrum is plotted.
How does a shake table result in FFT?
The beam base is excited at various frequencies in harmonic fashion on a shake table. This results in vibration in the beam. The accelerometer is ICP type, and details here. This accelerometer connects to a compatible FFT analyzer, make OROS-34, details here. Problem: I want to understand what the FFT of the original signal means.
How to check the system’s resonance with FFT?
In order to check system’s resonance, we should get FRF (frequency response function), the ratio between input fft and output fft. Output signal’s fft depends on input signal’s signature. Only with fft of output signal, we can’t insist the pick of frequency is resonance.