Base Excitation
The Base Excitation node is used to represent an acceleration that is applied at all constraints. The main use case is for modal based analyses, in which case it is not possible to directly prescribe nonzero displacements at constrained degrees of freedom. It is however possible to use Base Excitation in any type of dynamic analysis.
When a structure is subjected to a base excitation, displacements, velocities, and accelerations are measured relative to a space fixed coordinate system.
Coordinate System Selection
Select a coordinate system in which the base acceleration vector is represented. Only systems with space-independent axis directions are consistent with the assumptions of the base excitation.
Base Excitation
Enter the Base acceleration, ab.
As other global physics features, Base Excitation is global only within the interface, where it has been added. In case of several coupled structural interfaces in the model, you will need to add such feature under each of the involved interfaces. It will also have no effect on non-structural interfaces involved in a multiphysics coupling such as, for example, fluid–structure interaction.
Location in User Interface
Context Menus
Ribbon
Physics tab with a structural mechanics interface selected: