TSTEP (Subcase Information Entry)

Subcase Information Entry

TSTEP – Transient Time Step Set Selection

Description

The TSTEP command can be used in the Subcase Information section to select integration for transient analysis.

Format

TSTEP (type) = option

Example

TSTEP = 731
TSTEP (FOURIER) = 755

Argument	Options	Description
type	<TIME, FOURIER> Default = TIME	TIME:	The transient response is computed by time step integration in the time domain.
type	<TIME, FOURIER> Default = TIME	FOURIER:	The transient response is computed in the frequency domain using the Fourier transform method.

option	< SID > No default	SID:	Set identification number of a TSTEP bulk data entry.

Comments

A TSTEP entry must be selected to execute a transient analysis. TSTEP(FOURIER) is supported in both Direct and Modal Transient Analysis. Transient Response Analysis using Fourier Transformation via TSTEP(FOURIER) cannot be used in a model which also contains a Modal Frequency Response Analysis subcase. OptiStruct will error out in such cases.

2.	A TSTEP entry can also be used to execute a transient thermal analysis (only for type=TIME or default).

3.	For the application of time-dependent loads in modal frequency response analysis, a TSTEP bulk data entry must be selected by the TSTEP (FOURIER) command. The time-dependent loads will be recomputed in the frequency domain by a Fourier transform.