Define Steady State Function

Form:  Define Steady State Functions

Click the Define menu > Functions > Steady State command to display the Define Steady State Functions form, use the form to add, modify, or delete a steady-state function. A steady-state function is a list of function values versus frequency of excitation. The function values in a steady-state function may be normalized ground acceleration values or they may be multipliers for specified (force or displacement) load patterns.

Note: By default, the program pre-defines a unit constant steady-state function. This function may be modified or deleted.

Important: A steady-state function can be defined for any frequency range, f0 to fn. For all frequencies less that the first given frequency f0, the function value is assumed to be constant at the function value specified for f0. For all frequencies greater than the last given frequency fn, the function value is assumed to be constant at the function value specified for fn. If the function value needs to be zero outside of a particular frequency range, define the first and/or last function values to be zero.

Tip: The frequency range may be specified in Hz (cycles per second) or RPM (cycles per minute). Internally, the program always uses Hz, and results are reported in Hz.

• Add New Function button.

• 1. Select the type of function to be defined from the Choose Function Type to Add drop-down list:  Function from File or User Function.

  2. Click the Add Function button to display the type of function to be defined (Steady State Function Definition form for a function from file or Steady State Function Definition form for a user defined function).  

  3. Use the form to complete the definition of the function definition.

• Modify/Show Function button.

• 1. Highlight a function definition in the Functions display area.

  2. Click the Modify/Show button to access a form specific to the type of function selected (a function from file or a user defined function).  

  3. Use the form to make the appropriate modifications.  Note that a function from file definition can be changed to a user-defined definition.

• Delete Function button.

• 1. Highlight a function definition in the Functions display area.

  2. Click the Delete Function button to delete the selected function.  A function being used by an load case cannot be deleted.