Defining a surface traction load

Display the surface traction load editor using one of the following methods:

• To create a new surface traction load, follow the procedure outlined in Creating loads (Category: Mechanical; Types for Selected Step: Surface traction).

• To edit an existing surface traction load using menus or managers, see Editing step-dependent objects. To edit the region to which the load is applied, see Editing the region to which a prescribed condition is applied.

Click the arrow to the right of the Distribution field, and select the option of your choice from the list that appears:

• Select Uniform to define a load that is uniform over the surface.

• Select User-defined to define the magnitude of the load in user subroutine UTRACLOAD (for Abaqus/Standard). See the following sections for more information:

  • Specifying general job settings

  • UTRACLOAD

• Select an analytical field to define a spatially varying load. Only analytical fields that are valid for this load type are displayed in the selection list. Alternatively, you can click to create a new analytical field. (See The Analytical Field toolset,” for more information.)

Click the arrow to the right of the Traction field, and select the option of your choice from the list that appears:

• Select Shear to define a shear surface traction.

• Select General to define a general surface traction.

Specify the load direction.

1. Click next to Vector or Vector before projection to specify the coordinates of the direction vector.
2. By default, the traction components are specified with respect to the global axes. To refer to a local coordinate system for the direction components of the traction:

   • Select CSYS: Picked and click to pick a previously defined local coordinate system.

   • Select CSYS: User-defined and enter the name of a user subroutine that defines a local coordinate system.

3. If you selected CSYS: Picked, you can define an additional rotation about one of the axes. Click the arrow to the right of the Additional rotation about axis field, select the axis about which the other two axes will be rotated, and enter a value for the additional rotation angle.

In the Magnitude text field, enter the surface traction magnitude (units FL⁻²).

If desired, click the arrow to the right of the Amplitude field, and select the amplitude of your choice from the list that appears. Alternatively, you can click to create a new amplitude. (See The Amplitude toolset,” for more information.)

If desired, click the arrow to the right of the Traction is defined per unit field, and select deformed area to define the surface traction with respect to the current (deformed) area or undeformed area to define the surface traction with respect to the reference (original) area.

If you selected the General traction type, you can toggle off Follow rotation to define a non-follower load in a geometrically nonlinear analysis (i.e., the load always acts in a fixed global direction rather than rotating with the surface).

Click OK to save your data and to exit the editor.