Review the Analysis Parameters

1. Click Setup Model Setup Parameters. The Analysis Parameters dialog box displays.
2. Click on the Gravity/Acceleration tab. Note that standard gravity in the -Z direction, as defined within the previous stress analysis, has been copied to this design scenario.
3. Click on the Solution tab.
   • By default, the Number of buckling modes to calculate is set to 5. We will keep this setting.
     Note: Unlike other linear dynamics analyses, you do not need to run a natural frequency (modal) analysis prior to performing a critical buckling analysis. The critical buckling processor determines the buckling mode shapes and multipliers directly.
   • The default Upper cutoff buckling load factor is set to 10,000. Buckling modes are not output once the resultant buckling multiplier exceeds this value, even if the requested number of buckling modes has not been reached.
   • The default Lower cutoff buckling load factor is set to -0.1. This value prevents the output of negative buckling multipliers, except for those between 0 and -0.1.
     Note: A negative multiplier means that buckling occurs when the directions of the applied loads are reversed. For example, a structure subjected to only tensile loads will not buckle. Compressive loads are required for geometric instability. In such cases, the applied loads must be reversed to produce buckling, hence a negative buckling multiplier is calculated. The loads for this tutorial are compressive, and no negative buckling loads are expected.
4. Click OK to accept the default parameters.

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