Frequency Analysis Graph PropertyManager

The Frequency Analysis Graph PropertyManager allows you to create plots of frequencies versus effective mass participation factors and cumulative effective mass participation factors.

To open this PropertyManager, run a frequency or linear dynamic study. Right-click Results and select Define Frequency Response Graph.

Frequency vs.

  Mode Number Creates a line graph of resonant frequencies versus mode numbers. Lists the results under Summary.
  Effective mass participation factor (EMPF) Creates a bar graph that shows the effective mass participation factors (EMPF) for the global X, Y, and Z directions for each mode. Lists the results under Summary.
The effective mass participation factor represents the percentage of the system mass that participates in a particular mode. It provides a measure of the energy contained within each resonant mode. A mode with a large EMPF is usually a significant contributor to the dynamic response of a system.
  Cumulative effective mass participation factor (CEMPF) Creates a line graph that shows the cumulative effective mass participation factors for the global X, Y, and Z directions. Lists the results under Summary.
Mass participation factors are important in determining how many modes should be considered to capture adequately the dynamic response of a structure. Many codes require that the number of modes considered must contribute to a CEMPF of at least 80% of the system mass in the direction of excitation.

Summary

  Show Frequencies (Hz) where the EMPF is greater than: Shows the frequency range where the effective mass participation factor (for the selected global coordinate direction) is greater than the % value you enter.
  Show Frequencies (Hz) where the CEMPF is greater than: Shows the frequency range (min - max) where the cumulative effective mass participation factor (for the selected global coordinate direction) is greater than the % value you enter.
  X Y Z Select the global coordinate direction considered for the EMPF and CEMPF.

Report Options

Save Saves the results to a comma delimited *.csv file. Use a text editor or Microsoft Excel to view this file.