frequency) as well as higher (nonzero frequency) free body modes.Table 3.2: Loads Applicable in a
Modal Analysis (p. 45) shows the commands to apply displacement constraints. Notice that you can
apply them either on the solid model (keypoints, lines, and areas) or on the finite element model (nodes
and elements). For a general discussion of solid-model loads versus finite-element loads, see Loading
in the Basic Analysis Guide.
If you are going to perform a downstream harmonic or transient mode-superposition analysis, you can
apply other load types as well (see Generating and Using Multiple Loads in Mode-Superposition Ana-
lyses (p. 68)).
Note
Loads specified using tabular boundary conditions with TIME as the primary variable (see
the *DIM command) will have the table value at TIME equal to zero.
Table 3.2: Loads Applicable in a Modal Analysis
Cmd Fam- GUI Path
ily
Cat-
egory
Load Type
Main Menu> Solution> Define Loads>
Apply> Structural> Displacement
Con- D
straints
Displacement (UX, UY, UZ,
ROTX, ROTY, ROTZ)
In an analysis, loads can be applied, removed, operated on, or listed.
3.4.3.1. Applying Loads Using Commands
Table 3.3: Load Commands for a Modal Analysis (p. 45) lists all the commands you can use to apply
loads in a modal analysis.
Table 3.3: Load Commands for a Modal Analysis
Apply Set-
tings
Oper-
ate
Ap- Delete List
ply
Solid Entity
Model or
FE
Load Type
DK- DTRAN -
LIST
Solid Mod- Keypoints DK DKDELE
el
Displacement
Solid Mod- Lines DL DLDELE DLLIST DTRAN -
el
DAL- DTRAN -
IST
Solid Mod- Areas DA DADELE
el
DSYM,
DCUM
Finite Elem Nodes D DDELE DLIST DSCALE
3.4.3.2. Applying Loads Using the GUI.
All loading operations (except List; see Listing Loads (p. 46)) are accessed through a series of cascading
menus. From the Solution menu, you select the operation (apply, delete, and so on), then the load type
(displacement, force, and so on), and then the object to which you are applying the load (keypoint,
line, node, and so on).
For example, to apply a displacement load to a line, follow this GUI path:
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Applying Loads and Obtaining the Solution