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Insufficiently Constrained Models
If a run ends in an error and the summary or log file informs you that your model is insufficiently constrained for analysis, you should examine your model and attempt to locate the problem. In some cases, you may want to look at the AutoGEM mesh to determine whether the problem arises from the element configuration and quality. Insufficiently constrained models can be the result of:
Problems with Elements
Problems with Properties
Problems with Loads and Constraints
Unless you are doing a modal analysis of a free body with rigid mode search on, your model must satisfy the following rules:
Attach the structure to ground such that you can apply loads to the structure from any direction without causing rigid body motion.
Connect all parts of the structure to each other such that you can apply loads to any part of the structure without causing unopposed motion of any part of the structure.
The structure must be capable of resisting loads from any direction by transmitting the loads to ground at the constraints. If the structure or any part of the structure is capable of undeformed motion—rigid-body translation or rotation—under some type of loading, you must add appropriate constraints to resist that rigid-body motion.