Mechanical APDL Structural Analysis Guide

Option Command GUI Path

Main Menu> Solution> Load Step Opts> Time/Fre-

quenc> Time Integration

Transient Integration TINTP

Parameters

ALPHAD,

BETAD,DM-

Damping Main Menu> Solution> Load Step Opts>

Time/Frequenc> Damping

PRAT,

MDAMP

Main Menu> Solution> Load Step Opts>

Other> Change Mat Props> Material Models>

Structural> Damping

General Options

Main Menu> Solution> Load Step Opts> Time/Fre-

quenc> Time-Time Step

Integration Time Step DELTIM

Output Control Options

Main Menu> Solution> Load Step Opts> Output Ctrls>

Solu Printout

Printed Output OUTPR

• Dynamics options include the following:
  
  
  • Transient Integration Parameters (TINTP)
  
  
  
  

Transient integration parameters control the nature of the Newmark time integration

technique. The default is to use the constant average acceleration scheme; see your

Mechanical APDL Theory Reference for further details.

• Damping

Damping in some form is present in most structures and should be included in your ana-

lysis. You can specify five forms of damping in a mode-superposition transient dynamic

analysis:

Alpha (mass) damping (ALPHAD)

Beta (stiffness) damping (BETAD)

Constant damping ratio (DMPRAT)

Modal damping (MDAMP)

See Damping (p. 2) for further details.

• The only valid general option for the first load step is integration time step (DELTIM), which is as-
  sumed to be constant throughout the transient. By default, the integration time step is assumed
  to be 1/(20f), where f is the highest frequency chosen for the solution.The DELTIM command is
  valid only in the first load step and is ignored in subsequent load steps.

Note

If you do issue the TIME command in the first load step, it will be ignored. The

first solution is always a static solution at TIME = 0.

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

Transient Dynamic Analysis