Mechanical APDL Basic Analysis Guide - Ansys

Chapter 2: Loading
Discipline
Degree of Freedom
Turbulent Dissipation Rate
ENDS
ANSYS Label
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
Nodes
Keypoints
Lines
Areas
Transfer
Location
Basic Commands
D, DLIST, DDELE
DK, DKLIST, DKDELE
DL, DLLIST, DLDELE
DA, DALIST, DADELE
SBCTRAN
Additional Commands
DSYM, DSCALE, DCUM
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 generates 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 (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 illustrated in Figure 2.6 (p. 29). The DL and DA commands work in a
similar fashion when you apply symmetry or antisymmetry conditions on lines and areas.
You can use the DL and DA commands to apply velocities, pressures, temperatures, and turbulence quantities
on lines and areas for FLOTRAN analyses. At your discretion, you can apply boundary conditions at the
endpoints of the lines and the edges of areas.
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