How to calculate magnitude and phase angle of a discrete Fourier Transform function using HyperGraph?
There are some very good reasons for working in the frequency domain:
- Some complicated operations in the time domain become simple in the frequency domain, for example convolution in the time domain becomes a simple multiplication in the frequency domain.
- The relationship between the excitation and the response of a structure is often more easily understood in the frequency domain.
- An analysis in frequency domain could provide a lot of convenience and a better insight of the system where one wants to know at which frequency(range) the system has an issue, and at which frequencies the contributors are located.
Typical frequency domain analysis types of OptiStruct: Modal FRF Analysis, Random Response Analysis, ERP/Infinite Element Acoustic Analysis
A simple example was created to show the process. Please open the *.tpl file in HyperGraph to review the details.
- Windows 1,2,3: 3 curves of sinusoidal response
- Windows 4: summation of the above 3 curves.
- Windows 5 and 6: the magnitude and phase were calculated respectively. The original phase angle is measured in radians. In this example it's converted to degrees.
- dftmag: Magnitude of a discrete Fourier Transform (dFT) function.
- dftphase: Phase angle of a discrete Fourier Transform (dFT) function.