Power Spectral Density Specification
Description: Defines load set power spectral density factors for use in random analysis having the frequency dependent form.
Format:
Example:
| Field | Definition | Type | Default |
|---|---|---|---|
| SID | Random analysis set identification number. | Integer > 0 | Required |
| J | Subcase identification number of the excited load set. | Integer > 0 | Required |
| K | Subcase identification number of the applied load set. | Integer > 0 or blank, K ≥ J | Required |
| X, Y | Components of complex number. | Real | 0.0 |
| TID | Identification number of a TABRND1 card which defines G(F) | Integer ≥ 0 or blank | See Remark 4 |
Remarks:
- Set identification numbers must be selected with the Case Control command (RANDOM=SID).
- For auto spectral density, J = K, X must be greater than zero, and Y must be equal to zero.
- For uncoupled power spectral density functions (i.e., no J < K entries), any number of J = K entries are allowed with unique values of J. For coupled power spectral density functions (i.e., some J < K entries), a maximum of four entries may be specified.
- For TID=0 or blank, G(F)=1.0.
- RANDPS Bulk Data entries may not reference subcases in a different loop. Loops are defined by a change in the FREQUENCY command.