Prescribed Acceleration

The node adds an edge, boundary, domain, or point condition where the translational or rotational acceleration is prescribed in one or more directions. The prescribed acceleration condition is applicable for Time Dependent and Frequency Domain studies. With this condition it is possible to prescribe an acceleration in one direction, leaving the shell free in the other directions.

The Prescribed Acceleration node is a constraint, and overrides any other constraint on the same selection.


	For details about prescribed velocities and accelerations, see Prescribed Displacements, Velocities, and Accelerations.

Coordinate System Selection

Specify the coordinate system to use for specifying the prescribed acceleration. The coordinate system selection is based on the geometric entity level.


	Coordinate systems with directions that change with time should not be used. If you choose another, local coordinate system, the acceleration components change accordingly.

Boundaries

From the list select from:

•

(the default)

•

(a predefined normal-tangential coordinate system)

•

Any additional user-defined coordinate system

Edges

From the list select from:

•

(the default).


	For details about the definition of local edge systems, see Local edge system.

•

(the standard global coordinate system).

•

Any additional user-defined coordinate system.

Points

From the list select from:

•

(the default)

•

Any additional user-defined coordinate system

Depending on the selected coordinate system, the acceleration components change accordingly.

Face Defining the local edge system

This setting is used in conjunction with a . If the acceleration is prescribed for an edge which is shared between boundaries, the edge system can be ambiguous. Select the boundary which should define the edge system. The default is .


	This section is available only for edges in the Shell interface and is only visible if the selected coordinate system is Local edge system.

Prescribed Acceleration

To define a prescribed acceleration for each spatial direction (x, y, and z), select one or more of the , , and check boxes. Then enter a value or expression for the prescribed acceleration components ax, ay, and az.

Prescribed Angular Acceleration

To define a prescribed angular acceleration for each spatial direction (x, y, and z), select one or all of the , , and check boxes and enter a value or expression for in each

, or

field.


	You can add a Harmonic Perturbation subnode for specifying a harmonic variation of the values of the prescribed acceleration in a frequency domain analysis of perturbation type.

Location in User Interface

Context Menus

(Edge)
(Boundary)

Ribbon

Physics tab with selected: