I need to do a PSD analysis in Abaqus, and I do not know how to do it. I have the PSD curve, but I am not sure how to implement it in Abaqus in order to obtain results. Any guidelines?
Thanks in advance!!
Since you have attached a snippet from the standard on shock and vibration testing of a railway equipment, I presume you want to predict a response in a similar application.
Please note, that the procedure described in section 6.3.11 of Abaqus Analysis User's Guide is valid only for linear systems. I recommend employing the time-dependent kinematic excitation in case of non-linear systems (e.g. systems with contacts). You can generate an excitation process from given PSD employing the inverse Fourier transform (IFT). Note that the PSD introduced in the enclosed standard lacks any information about phase and therefore IFT is not unambiguous. Thus you can generate many various time-dependent processes with the same PSD.
If you need a (Matlab) code for generating PSD from Fourier spectrum, let me know or check https://www.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html
The PSD is merely the mean of a series of FFT taken at + 2 standard deviations, why not just use a series of FFT and look at the complete results. This is reasonably easy to prove with real signals.
Maybe this helps?
Abaqus Analysis User's Guide: 6.3.11 Random response analysis
Abaqus Benchmarks Guide: 4.5.8 Test 13R: Simply supported thin square plate: random forced vibration
Since you have attached a snippet from the standard on shock and vibration testing of a railway equipment, I presume you want to predict a response in a similar application.
Please note, that the procedure described in section 6.3.11 of Abaqus Analysis User's Guide is valid only for linear systems. I recommend employing the time-dependent kinematic excitation in case of non-linear systems (e.g. systems with contacts). You can generate an excitation process from given PSD employing the inverse Fourier transform (IFT). Note that the PSD introduced in the enclosed standard lacks any information about phase and therefore IFT is not unambiguous. Thus you can generate many various time-dependent processes with the same PSD.
If you need a (Matlab) code for generating PSD from Fourier spectrum, let me know or check https://www.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html
Thanks a lot for your help Luboš, It seems you are an expert on the field.
I was not aware that 6.3.11 was only for linear systems, good to know it.
I will take a look to the matlab code and maybe I ask you again.
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