Mechanical APDL Basic Analysis Guide

Discipline Degree of Freedom Label

Scalar Potential MAG

Electric Voltage VOLT

Acoustic Pressure PRES

Displacement UX, UY, UZ

Diffusion Concentration CONC

1. For structural static and transient analyses, velocities and accelerations can be applied as finite element
   loads on nodes using the D command. Velocities can be applied in static or transient analyses; accelerations
   can only be applied in transient analyses. The labels for these loads are as follows:

VELX, VELY,VELZ - translational velocities

OMGX, OMGY, OMGZ - rotational velocities

ACCX, ACCY, ACCZ - translational accelerations

DMGX, DMGY, DMGZ -rotational accelerations

Although these are not strictly degree-of-freedom constraints, they are boundary conditions that

act upon the translation and rotation degrees of freedom. See the D command for more information.

Table 2.2: Commands for DOF Constraints

Location Basic Commands Additional Commands

Nodes D,DLIST,DDELE DSYM,DSCALE,DCUM

Keypoints DK,DKLIST,DKDELE -

Lines DL,DLLIST,DLDELE -

Areas DA,DALIST,DADELE -

Transfer SBCTRAN DTRAN

Following are some of the GUI paths you can use to apply DOF constraints:

GUI:

Main Menu> Preprocessor> Loads> Define Loads> Apply> load type> On Nodes

Utility Menu> List> Loads> DOF Constraints> On All Keypoints (or On Picked KPs)

Main Menu> Solution> Define Loads> Apply> load type> On Lines

See the Command Reference for additional GUI path information and for descriptions of the commands
listed in Table 2.2: Commands for DOF Constraints (p. 28).

2.5.4. Applying Symmetry or Antisymmetry Boundary Conditions

Use the DSYM command to apply symmetry or antisymmetry boundary conditions on a plane of nodes.
The command generat es the appropriate DOF constraints. See the Command Reference for the list of
constraints generated.

In a structural analysis, for example, a symmetry boundary condition means that out-of-plane translations
and in-plane rotations are set to zero, and an antisymmetry condition means that in-plane translations
and out-of-plane rotations are set to zero. (See Figure 2.5: Symmetry and Antisymmetry Boundary Con-
ditions (p. 29).) All nodes on the symmetry plane are rotated into the coordinate system specified by
the KCN field on the DSYM command. The use of symmetry and antisymmetry boundary conditions is

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

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