Acceleration of a Series of Harmonic Analyses (Saving and Loading Modal Analysis Results)

Harmonic analysis using the superposition method is based on the results of modal analysis, and it is this modal analysis that takes the most time to calculate. To reduce the time required to calculate harmonic analysis, it is possible to use saved modal analysis results. To do this, in the modal analysis, you need to use the option to save the eigenvalues and modal displacement vectors to a file with the *.bin extension. This option allows to conduct multiple harmonic analysis calculations on the same modal analysis results, for example, for different loads (forces, pressures, etc., except for displacements) or different damping coefficient options.

Go to Calculation – Modal Frequency – General and enable the "Save Results for Future Calculations" checkbox:

Clicking "Browse..." opens the "Select Eigen Calculation File" window with the working directory. Next, you must specify the full path to the *.bin file location and its name:

The saved file will contain information about the eigenvalues and modal displacement vectors.

Example of a command to save the results of modal analysis:

analysis type eigenfrequencies dim3 preload off
eigenvalue find 10 from 0.0 to 60.0 save modal_result to 
'C:\Users\Documents\CAE-Fidesys-9.0\modal_result.bin'

To use saved modal analysis results, go to Calculation – Frequency Analysis – General and enable the "Use Saved Results" checkbox:

Clicking "Browse..." opens the "Select Eigen Calculation File" window with the working directory. Next, you must specify the full path to the location of the saved *.bin file:

Example command for using saved modal analysis results to calculate harmonic analysis:

analysis type harmonic dim3 preload off
harmonic method mode_superposition interval from 0.0 to 60.0 steps_count 1000 frequency_spacing_type 
linear use modal_results from 'C:\Users\Documents\CAE-Fidesys-9.0\modal_result.bin'

When selecting a calculation folder, it is important that the *.bin file for the modal analysis results is kept separate, as all files are deleted before the calculation begins, and this file will also be deleted.