The Underconstrained Bodies
tool detects the bodies in a part or assembly that are not sufficiently constrained during
simulation and can exhibit rigid body modes.
The Underconstrained
Bodies tool is available for static studies.
To open the Underconstrained
Bodies PropertyManager, do one of the following:
- From a static study tree, right-click Connections
and click Underconstrained Bodies
.
- From the CommandManager, select Diagnostic Tools, and click Underconstrained Bodies
.
Bodies that are not adequately supported by fixtures, connectors, bonded
conditions, or contact interactions can translate or rotate freely. A body that is not
constrained has six rigid body modes: three translational and three rotational.
In SOLIDWORKS Simulation Professional and SOLIDWORKS Simulation
Premium, the underconstrained bodies algorithm, in addition to fixtures and bonded
conditions, takes into account the contact interactions that you define in a static
study when analyzing rigid body modes.
In SOLIDWORKS
Simulation Standard and SOLIDWORKS Premium, the underconstrained bodies algorithm
does not consider any contact interactions that you define. In this case, bodies
with bolt connectors and contact definitions can be sufficiently constrained for a
successful simulation, but are shown in the list of unconstrained bodies under
Results.
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Calculate
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Detects the bodies in a part or assembly that exhibit
translational or rotational rigid body modes. In
SOLIDWORKS Simulation Standard and SOLIDWORKS Premium, the
analysis tool applies a coarse mesh and runs the static study
(using the Direct Sparse Solver) with all defined loads,
interactions, and boundary conditions.
In
SOLIDWORKS Simulation Professional and SOLIDWORKS Simulation
Premium, the detection of rigid body modes is faster because the
solver performs Singular Value Decomposition (SVD) over the
reduced stiffness matrix. See also Advanced Detection of Underconstrained Bodies.
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Results
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Lists the bodies or group of bodies that exhibit
rigid body modes.
Select one of the listed degrees of freedom (for
example, Translation 1
or Rotation 1) to view
an animated translation or rotation of the underconstrained
bodies. A green arrow in the graphics area points to the
direction of free movement (translation or rotation).
If no rigid bodies are detected, the solver
issues a message that the model is fully constrained.
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