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CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
12

After dynamic initialization and basic equation assembly are completed, CAESAR II opens the Dynamic Eigensolver, which calculates natural frequencies and modes of vibration.

Each natural frequency appears as it is calculated, along with the lapsed time of the analysis. The processor searches for the natural frequencies, starting with the lowest, and continues until the frequency cutoff is exceeded or the mode count reaches its limit. Both the frequency cutoff and mode cutoff are dynamic analysis control parameters. The amount of time to calculate or find these frequencies is a function of the system size, the grouping of the frequencies and the cutoff settings.

Eigensolution may be canceled at any time, with the analysis continuing using the mode shapes calculated up to that point. After the last frequency is calculated, the software uses the Sturm Sequence Check to confirm that no modes were skipped. If the check fails, you can return to the dynamic input or continue with the spectral analysis. Sturm Sequence Check failures are usually satisfied if the frequency cutoff is set to a value greater than the last frequency calculated.

After calculations are complete, control is passed to the Dynamic Output Processor. You can review natural frequencies and mode shapes in text format. You can also display the node shapes in and animated format.