Mechanical APDL Structural Analysis Guide

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