Skip to main content

Applied Displacements

Applied displacements impose fixed displacements on specified nodes. They are different from other load types and are also distinct from settlements. They function differently between linear (GSS) and nonlinear (GsRelax) solvers in that they result in defined displacements in linear analyses, but act as initial imperfections for nonlinear.

They can be applied in local (node constraint axis), global, or user-defined axis directions. User-defined axes can be Cartesian, cylindrical, or spherical.

Applied displacements with linear analysis​

An applied displacement imposes a fixed displacement on a specific node in the structure and calculates the resulting forces that lead to the deformation at the specified degree of freedom. This method can be used to assess the stiffness of a structure by constraining certain degrees of freedom to move a fixed amount and measuring the resulting forces.

They apply to a specific load case, while the node remains free in other load cases. These displacements are managed using Lagrange multipliers, which calculate the forces needed to generate the specified displacements, if feasible.

Note: Applied displacements should not be combined with other loads in the same analysis case.

Applied displacements with nonlinear analysis​

In nonlinear static analyses using the GsRelax solver, applied displacements are treated as initial imperfections to start the analysis. As a result, the final displacements are not guaranteed to match the specified values but are instead determined by the equilibrium of the nodes.

Definition​

Name

The name is only used as a convenient way of identifying a load. Optional.

Node List

This specifies a list of nodes to be displaced using any one of the forms detailed in Lists. The list may be a single item.

In sculpt: The node list is set to the current selection set. The node list cannot be edited in the dialog.

Load case

This is the load case in which the displacement applies. The load case gives a way of grouping load effects together.

Axis

The axis in which the displacement is applied (global by default).

Direction

The direction of the loading, in the specified axis direction.

Value

The magnitude of the displacement or rotation.