# RANDOM

Subcase Information Entry Selects the RANDPS and RANDT1 Bulk Data Entries to be used in Random Response Analysis.

RANDOM = n

## Example

RANDOM = 177

## Definitions

Argument Options Description
n (Integer > 0) The RANDOM Subcase Information Entry can directly reference the identification number of RANDPS and RANDT1 Bulk Data Entries. 1

The RANDOM Subcase Information Entry can also reference a SET I/O Options Entry. This SET I/O Options Entry should reference a list of RANDPS/RANDT1 Bulk Data Entries. 2

1. If the RANDOM Subcase Entry is pointing directly to a RANDPS entry, then it is subcase dependent. A separate subcase can be used to define Random Response Analysis with the optional ANALYSIS=RANDOM entry. If such a RANDOM entry is instead defined in the global subcase section (above the first subcase), then OptiStruct will internally create a RANDOM subcase with ANALYSIS=RANDOM.
Example: RANDOM entry pointing to RANDPS ID from Global Subcase
RANDOM = 334
SUBCASE 1
…
BEGIN BULK
RANDPS, 334, …
Example: RANDOM entry pointing to RANDPS ID from within Random Subcase
SUBCASE 1
…
SUBCASE 2
ANALYSIS=RANDOM
RANDOM=334
BEGIN BULK
RANDPS, 334, …
2. If the RANDOM Subcase Information Entry is pointing to a SET I/O Entry, then it should not be defined within any subcase and should only be specified in the global subcase section (above the first subcase). For this, OptiStruct will internally create multiple RANDOM subcases with ANALYSIS=RANDOM (as many subcases are internally created as RANDPS entries referenced on the SET I/O Entry).
When the RANDOM Subcase Entry is pointing to a SET of RANDPS IDs, then the random results are output separately for each RANDPS entry within the SET.
Note: If the SET I/O Entry and RANDPS Bulk Data Entry have the same ID number, then OptiStruct selects the RANDPS Bulk Data Entry in this case and the SET I/O Entry is ignored.
Example: RANDOM entry in Global Subcase pointing to SET ID referencing RANDPS IDs
SET 455 = 334, 335, 336
RANDOM = 455
SUBCASE 1
…
BEGIN BULK
RANDPS, 334, …
RANDPS, 335, …
RANDPS, 336, …