I'm trying to find out the damping ratio using Continuous Wavelet Transform. For that, I need to convert my original signal t(ime vs Acc of a bridge) to a decay function using Random Decrement (RD) Method. I wonder how to convert this using Matlab since it does not have any direct function. Do I need to code the algorithm according to the mathematical background of RD or is there any other convenient way to do that?
Thanks
Hi Yashodhya
Thank you for contacting me. I have an old matlab program that worked very good !!
I will send you the required files, you can make better coding , e.g. replacing the avr.m by matlab function, and even changing the extr.m which find the max, min and zero crossing of the signal by simple matlab functions.
by the way, as you know, you have to filter your signal using bandpass filter of your interested frequency (plot the FFT of the signal and find the dominant e.g first mode freq.)
you need long data (several 100 sec) in order to have a good decay.
I send you a set of microtremore data data you can use for your ref.
If you need further assist, pls feel free contacting me
Regards
Ali
Dear Niousha
I am trying to identify the damping ratio of a structure from seismic response using HHT, however, some references mentions that a RDT is needed to filler the imf of signals before the damping ratio acquired, and I can not find any functions can be used in MATLAB directly. can you send me the program?
best wishes.
Hi Jiao,
There is a specific inbuilt function called "RDT" in MATLAB for random decrement method.
See the following link. Hope this would help you to solve your problem.
https://www.mathworks.com/matlabcentral/fileexchange/55557-modal-parameters-identification-from-ambient-vibrations--sdof-?focused=5974052&tab=example&requestedDomain=www.mathworks.com
Regards
Yash
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