The placement of symbols on a model can depend on the type of prescribed condition that the symbols represent and the type of region to which the prescribed condition is applied. Table 16–1 indicates where symbols appear on geometric models, and Table 16–2 indicates where symbols appear on meshed models.
Table 16–1 Symbol location on native geometry.
| Region type to which the prescribed condition is applied | Location of symbols on the model |
|---|---|
| Vertex | At the vertex |
| Edge | Equally spaced along the edge |
| Assembly-level wire | At the midpoint of the wire |
| Face | Equally spaced over the interior of the face for directional prescribed conditions (e.g., pressure load) |
| Equally spaced along the edges of the face for nondirectional prescribed conditions (e.g., surface charge and boundary conditions) | |
| Cell | Equally spaced along each edge of the cell |
| Whole model | At the point required to define the rigid body motion (inertia relief load only); otherwise, at the triad indicating the origin and orientation of the global coordinate system |
Table 16–2 Symbol location on meshes.
| Region type to which the prescribed condition is applied | Location of symbols on the model |
|---|---|
| Node | At the node |
| Element edge (for two-dimensional meshes) | At the midpoint of the element edge |
| Element face (for three-dimensional meshes) | At the centroid of the element face |
| Assembly-level wire | At the midpoint of the wire |
When a boundary condition fixes a degree of freedom in place, the arrow representing that component points into the region and lacks a stem. For example, the boundary condition in Figure 16–12 fixes degrees of freedom 1, 2, and 3 in place.
Likewise, if a positive pressure load is applied to a region, the arrows representing that pressure load point into the region, as illustrated in Figure 16–13. If a load is defined to have a complex magnitude and the real and imaginary parts have different signs (for example,
), the load will appear as an arrow with two ends. In all other cases, arrows representing components of a prescribed condition point out from the region.Note: When a component of a concentrated force is zero, no arrow appears for that component. Likewise, when a boundary condition leaves a degree of freedom unconstrained, no arrow appears for that component.
