da

Mapdl.da(area='', lab='', value1='', value2='', **kwargs)

Defines degree-of-freedom constraints on areas.

APDL Command: DA

Parameters
  • area – Area on which constraints are to be specified. If ALL, apply to all selected areas [ASEL]. A component name may also be substituted for AREA.

  • lab

    Symmetry label (see below):

    SYMM - Generate symmetry constraints. Requires no Value1 or Value2.

    ASYM - Generate antisymmetry constraints. Requires no Value1 or Value2.

    ANSYS DOF labels:

    UX - Displacement in X direction.

    UY - Displacement in Y direction.

    UZ - Displacement in Z direction.

    ROTX - Rotation about X axis.

    ROTY - Rotation about Y axis.

    ROTZ - Rotation about Z axis.

    HDSP - Hydrostatic pressure.

    PRES - Pressure.

    TEMP, TBOT, TE2, TE3, …, TTOP - Temperature.

    MAG - Magnetic scalar potential (see 2 below).

    VOLT - Electric scalar potential (see 3 below).

    AZ - Magnetic vector potential in Z direction (see 4 below).

    CONC - Concentration.

    ALL - Applies all appropriate DOF labels except HDSP.

  • value1 – Value of DOF or table name reference on the area. Valid for all DOF labels. To specify a table, enclose the table name in % signs (e.g., DA,AREA,TEMP,%tabname%). Use the *DIM command to define a table.

  • value2 – For MAG and VOLT DOFs:

Notes

For elements SOLID236 and SOLID237, if Lab = AZ and Value1 = 0, this sets the flux-parallel condition for the edge formulation. (A flux- normal condition is the natural boundary condition.) Do not use the DA command to set the edge-flux DOF, AZ to a nonzero value.

If Lab = MAG and Value1 = 0, this sets the flux-normal condition for the magnetic scalar potential formulations (MSP) (A flux-parallel condition is the natural boundary condition for MSP.)

If Lab = VOLT and Value1 = 0, the J-normal condition is set (current density (J) flow normal to the area). (A J-parallel condition is the natural boundary condition.)

You can transfer constraints from areas to nodes with the DTRAN or SBCTRAN commands. See the DK command for information about generating other constraints on areas.

Symmetry and antisymmetry constraints are generated as described for the DSYM command.

Tabular boundary conditions (VALUE = %tabname%) are available only for the following degree of freedom labels: Electric (VOLT), Structural (UX, UY, UZ, ROTX, ROTY, ROTZ), Acoustic (PRES, UX, UY, UZ), and temperature (TEMP, TBOT, TE2, TE3, …, TTOP).

Constraints specified by the DA command can conflict with other specified constraints. See Resolution of Conflicting Constraint Specifications in the Basic Analysis Guide for details.

The DA command is also valid in PREP7.

Examples

Select all areas with a z-coordinate of 0, then set value for all degrees of freedom to be 0 on the selected areas.

>>> mapdl.asel('S', 'LOC', 'Z', 0)
>>> mapdl.da('ALL', 'ALL')

Apply symmetric boundary conditions on area 2.

>>> mapdl.da(2, 'SYMM')

Allow x-displacement on area 2.

>>> mapdl.da(2, 'UX', 1)