The Fixed support constraint boundary condition restricts all the translation degrees of freedom over the assigned entities to zero. It is used to model a portion of the geometry that is connected to a rigid body. This rigid body can be the ground, anchor point, foundation, or another relatively stiffer structure that will undergo negligible deformation under-supported loads.
The settings panel for the Fixed support boundary condition in the SimScale Workbench appears as shown in Figure 1:
The parameters of the constraint are:
$$ DX = 0 $$
$$ DY = 0 $$
$$ DZ = 0 $$
where \(DX\) is displacement in the X-direction.
As can be noticed, these conditions are equivalent to applying a fixed value constraint where all the displacements are explicitly set to zero.
When using the fixed support constraint boundary condition, it can be found that stress concentration and high-stress gradients might occur in the regions close to the assigned faces. According to Saint Venant’s principle, the stress distribution close to faces of load application (such as fixed faces), will always differ from the ideal distribution from an equivalent load.
Some actions to take in this case are:
Last updated: August 26th, 2022
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