Enforced acceleration (Nastran)

Use the Enforced Acceleration command to apply an enforced acceleration value at a specified location in a dynamic analysis. The options in the Enforced Acceleration dialog box correspond to the fields on the Nastran SPCD bulk data entry.

Note:

When you define an enforced acceleration constraint on geometry, a local coordinate system is created and applied to the underlying nodes. If local coordinate systems already exist at these nodes, the constraint's coordinate system may overwrite them. For example, if you define a constraint on a location where spring elements are defined, the constraint's coordinate system may overwrite the spring element definitions.

The enforced motion method

In Nastran, enforced motion (or acceleration) is used when you specify a base motion instead of, or in conjunction, with applied loads. A common application of an enforced motion or acceleration is an earthquake excitation applied to a building. In this example there are no applied loads. Instead, the base of the building undergoes an enforced displacement or acceleration time history.

For more information, see Overview of Enforced Motion in the Simcenter Nastran Basic Dynamic Analysis User’s Guide.

Supported solution sequences

The Enforced Acceleration command is available for the following Nastran solutions types:

• SOL 108 Direct Frequency Response

• SOL 109 Direct Transient Response

• SOL 111 Modal Frequency Response

• SOL 112 Modal Transient Response

Where do I find it?

Application	Pre/Post
Prerequisite	An active Simulation file with Simcenter Nastran or MSC Nastran as the specified solver and a supported solution type active
Command Finder	Enforced Acceleration
Simulation Navigator	In the appropriate solution or subcase, right-click Constraint Container→New Constraint→Enforced Acceleration

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

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Enforced acceleration (Nastran), Simcenter 3D 2021.1 Series

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