Frf,Modal analysis, Naturel frequencies
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Hi;
I have experiment data for time depending force and displacement values.
I need to plot Displacement (dB) - frequency grapf. what should be my x-axis?
B1=xlsread('frf.xlsx',1);
a = B1(1:50001,5:5);
ffa = fft(a);
F = B1(1:50001,6:6);
fff = fft(F);
H=ffa./fff;
aH =abs(H);
t_step=0.0002;
ts=1/t_step;
semilogy(aH)
1 Comment
Mathieu NOE
on 30 Dec 2020
hello
your method for converting from time to frequency is not the best
consider using tfestimate
[Txy,F] = tfestimate(X,Y,WINDOW,NOVERLAP,NFFT,Fs) returns the transfer
function estimate as a function of physical frequency. Fs is the
sampling frequency specified in hertz. If Fs is empty, it defaults to
1 Hz.
you will get the frequency vector F that is your x axis vector
Txy is a complex (vector) that you can convert to magnitude and phase like a Bode plot
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