Mechanical APDL Structural Analysis Guide

Jobname.RSX information from a previous VT Accelerator run. Note that in a VT Accelerator run, you

cannot restart a job in the middle; you can only rerun the job from the beginning with changes in the

input parameters.

• When setting AUTOTS, remember that this load step option (which is also known as time-step optimization
  in a transient analysis) increases or decreases the integration time step based on the response of the
  structure. For most problems, we recommend that you turn on automatic time stepping, with upper and
  lower limits for the integration time step. These limits, specified using DELTIM or NSUBST, help to limit
  the range of variation of the time step; see Automatic Time Stepping (p. 132) for more information. The
  default is ON.


• NSUBST and DELTIM are load step options that specify the integration time step for a transient analysis.
  The integration time step is the time increment used in the time integration of the equations of motion.
  You can specify the time increment directly or indirectly (that is, in terms of the number of substeps). The
  time step size determines the accuracy of the solution: the smaller its value, the higher the accuracy. You
  should consider several factors in order to calculate a "good" integration time step; see Guidelines for In-
  tegration Time Step (p. 130) for details.


• When setting OUTRES, keep this caution in mind:

Caution

By default, only the last substep (time-point) is written to the results file (Jobname.RST)

in a full transient dynamic analysis. To write all substeps, set the Frequency so that it

writes all of the substeps.

5.3.3.3. Using the Transient Tab

You can use the Transient tab to set the options listed in Table 5.1:Transient Tab Options (p. 114). For
specific information about using the Solution Controls dialog box to set these options, access the dialog
box, select the Transient tab, and click the Help button.

Table 5.1:Transient Tab Options

Option For more information about this option, see:

Specify whether time integration effects

are on or off (TIMINT)

• Performing a Nonlinear Transient Analysis (p. 254) in
  the Structural Analysis Guide

Specify whether to ramp the load change

over the load step or to step-apply the

load change (KBC)

• Stepped Versus Ramped Loads in the Basic Analysis
  Guide


• St epping or Ramping Loads in the Basic Analysis
  Guide

Specify mass and stiffness damping (AL-

PHAD,BETAD)

• Damping (p. 2) in the Structural Analysis Guide

Choose the time integration method,

Newmark or HHT (TRNOPT)

• Transient Analysis in the Mechanical APDL Theory
  Reference

Define integration parameters (TINTP) • Mechanical APDL Theory Reference

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Transient Dynamic Analysis