Brick Attributes: Face Support

Description

Assigns elastic supports to selected faces of brick elements.

Face supports can provide normal and lateral stiffness:

Normal stiffness acts in the direction perpendicular to the brick face.
Lateral stiffness acts in shear in the plane of the brick face.

Support attributes are freedom case dependent.

Dialog

K normal

Normal face support stiffness.

K lateral

Lateral face support stiffness.

Compression-only

If set, the support stiffness is active only when the brick moves towards the support (i.e., the support is active only in compression).

If not set, the support stiffness is active irrespective of whether the brick moves towards or away from the support (i.e., the support is active in both compression and tension).

Compression-only behaviour can only be considered in nonlinear analysis.

The lateral stiffness is not directly affected by this setting. However, if the normal stiffness becomes inactive due to the compression-only setting, the lateral stiffness is also deactivated.

Gap

When a non-zero gap is defined, the support stiffness becomes active only after the brick has moved to close the gap.

The gap may be positive or negative. A positive gap models a brick that is not yet resting on the support; the support becomes active after the brick moves to close the gap. A negative gap means that the brick is already in contact with, and pressed into the support by an amount equal to the magnitude of the gap value; that is, the brick is pre-compressed into the support. In the absence of other loads or constraints, a negative support gap causes the brick to deflect away from the support.

To consider the gap, the support type must be compression-only and a nonlinear analysis must be executed.

The lateral stiffness is not directly affected by this setting. However, if the normal stiffness becomes inactive due to the gap setting, the lateral stiffness is also deactivated.

Limited Bearing Capacity

If set, the compressive normal stress is limited to the specified Max value.

Behaves elastically (i.e., the unloading path is the same as the loading path and there are no residual displacements when unloaded).

Max

Maximum compressive normal stress that can be supported. Used only if Limited bearing is set.

This value is always positive.

Common Controls

Units

Stiffness: Pressure/Displacement (e.g., Pa/m, psi/in).

Gap: Length (e.g., m, in).