The Analyze component turns orange and reports that there are rigid bodies in the system.
This usually means that the system is kinematic and parts of the model are able to move freely without deformation. Perform the following the checks:
- Check the supports for forgotten support conditions.
- Check whether you defined a hinge next to a rotational support which allows the supported node to move freely.
- Plug the model into the EigenModes component. The first Eigenmodes will be the rigid body modes you forgot to mark. Save your model before doing that: Large models can take a long time to calculate.
- If the first few Eigenmodes seemingly show an un-deflected structure there might be beams in the system that rotate about their longitudinal axis. Enable Local Axes in the ModelView component and move the slider for scaling Deformation in order to check this.
- Turn trusses into beams by activating their bending-stiffness. Be aware of the fact that a node has to be fixed by at least three trusses that do not lie in one plane.
- Remember that trusses have no torsional or bending stiffness and thus cannot serve to fix the corresponding rotations on a beam that attaches to the same node.
- Check whether an element has zero area, height or Young’s modulus.