I have acceleration vs time data of array 1008*1 for 7 DOF quarter car model in vertical direction.
Simulation is of 10 seconds with step size 0.01, from where I can get matlab code for converting time domain acceleration to frequency weighted acceleration with Butterworth low pass high pass filter as per ISO 2631-1 standard.
In MATLAB there is a function called "fft" using this you can convert any time domain signal into frequency domain. MATLAB pages for this are below,
https://in.mathworks.com/help/ident/ref/fft.html
example pages,
https://in.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html
https://in.mathworks.com/matlabcentral/answers/558-fft-on-vibration-analysis
After that, you can used Butterworth filtering using the function "butter", you can design highpass, lowpass or a bandpass as per your choice or need. Reference page for this are below
https://in.mathworks.com/help/signal/ref/butter.html
Thnks ,
here is code which i got , the simulation time is 10 sec , fixed step 0.001 sec ,but is showing error:
x_initial = 10; % t,time for simulation
y_s = A ; % acceleration data from simulation by 'to workspce' block in simulink'
xi = 0:0.001:10; % set new time interval as 0.001s
y_s_new = interp1(x_initial,y_s,xi);% simulation data after interpolation by using 1-D interpolation (interp1) in matlab
%A Butterworth filter is used as the low pass filter, and the low pass filtering process is shown below%
Fs = 1000;% Sampling frequency
fNorm = 10/(Fs/2);% Normalized cutoff frequency for Butterworth
filter
[b,a] = butter(5,fNorm,'low')% Butterworth filter
fy_s = filter(b,a,y_s);% low pass filtering
%Fourier Transform
Fs=1000;% Sampling frequency in Hz
hamming=0.5; %Low hamming in Hz
L=size(In,1);
NFFT = 2^nextpow2(L);
hammingwindow=((2*hamming)/Fs);
Ham=tukeywin(NFFT, hammingwindow);
y = (fft(In,NFFT))/L;
y=Ham.*y;
x = (Fs/2)*linspace(0,1,NFFT/2+1);
y_fft =2*abs(y(1:0.5*NFFT+1));
The error received is:
??? Error using ==> interp1 at 125
X and Y must be of the same length.
Error in ==> Filter at 6
y_s_new = interp1(x_initial,y_s,xi);% simulation data after interpolation by using 1-D
interpolation (interp1) in matlab
The above code Shows the error
The error received is:
??? Error using ==> interp1 at 125
X and Y must be of the same length.
Error in ==> Filter at 6
y_s_new = interp1(x_initial,y_s,xi);% simulation data after interpolation by using 1-D
interpolation (interp1) in matlab
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