FFT, acceleration-frequency, vibration

7 views (last 30 days)
Gloria
Gloria on 8 Oct 2019
Hello everybody ;
I have torsional angle values and axial displacements.
I first try to draw the acceleration-frequency graph by taking the derivative of values first and then applying fft.
I'm trying to figure out where I made a mistake at Matlab.
When I thought that the graph I had drawn was correct, my friend calculated it using Phayton,
and our results turned out very different, and his are quite close to the correct one.
I'm trying to figure out where I made a mistake at Matlab.
I would be glad if you help.
%% For two times derivatives
t=t1(1:end-2);
t_step = 0.005;
v=diff(x1)./t_step;
a=diff(v)./t_step;
%% for fft
ts=1/t_step;
N2=2^nextpow2(length(a));
freq2=(0:1:(N2-1)/2)*ts/N2;
fx1=fft(a,N2)/N2*2;
ffx1=abs(fx1(1:floor(N2/2)));
plot(freq2,ffx1),xlabel('Frequency (Hz)'), ylabel('Acceleration (m/s^2)')

Answers (0)

Categories

Find more on Vibration Analysis in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by