M. To define a time history type by spectrum
To define a time history type using spectral parameters, use the following procedure.
Loading ribbon tab, select the
tool in the
Dynamic Specifications group.
The Add New: Time History Definitions dialog opens.
- Type an Integration Time Step value in seconds.
- (Optional) Select the Consider Missing Mass Mode option if necessary.
- (Optional) Select the Save option to generate a file with time history data.
- Select the Loading Type for your data:
- Select the Spectrum option in the Function Options group.
Specify the time data:
- Enter the maximum time (in second) in the generated time history in the Tmax field.
- Enter the time step (in seconds) in the DeltaT field.
- Enter the time at the end of rising acceleration in the T1 field.
- Enter the time at the end of the steady acceleration in the T2 field.
- Enter the time at the end of the acceleration decay in the T3 field.
- Enter the damping ratio in the Damp field.
Specify the options:
- (Optional) Type a Random Seed value. Enter a positive integer (in the range of 1 to 2,147,483,647) to be used as a unique random number generation "seed." A unique time history will be produced for each seed value. Change this value when you want to produce a "different (from the time history generated with the prior seed value)" but statistically equivalent time history.
- Enter the No of digitized Freq. This is the number of equally spaced frequencies at which the input shock spectrum is re-digitized (by interpolation).
- Enter the No. of Iteration which will be used to perfect the computed time history.
- Click Add.