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The purpose of the Associate Action is to define a logical connection between geometry and finite elements. The associate action allows users to associate finite element entities to geometries, if they are unassociated, thereby enabling the user to apply loads, boundary conditions and properties directly to the geometry instead of to the individual finite element entities. When associating finite elements to geometric entities, two general rules apply:
Rule 1: The nodes are associated with the lowest order existing topological entity first which is a vertex, then an edge, face, and body.
Rule 2: The finite elements are associated with the same order geometric entity, i.e., a beam element with a curve, or a quad element with a surface.
A typical application would be the importing of an IGES file which has both a geometry and a finite element model. However, there is no associativity between either of the models. The Associate Action will provide the capability of logically connecting the two models together, thus defining an associativity between them.
Association of elements and nodes are based on their geometric proximity to the selected geometry. When associating elements to geometry (except points) users have the option of specifying whether or not a “mesh definition” must be created on the curves or edges. This option creates an implicit mesh record on the curve that allows the mesher to create congruent meshes across neighboring geometries.
Caution: | When a mesh is associated, to say a surface, and “mesh definition” is requested to be created, if a “mesh definition” already exists on an edge of the surface a warning is issued about a possible non congruent mesh along that edge. This is because the associate code simply duplicates the existing mesh definition as multiple mesh definitions cannot exist on an edge to produce a congruent mesh. |
Four methods for associating nodes and finite elements to geometry are provided: Point, Curve, Surface, and Solid.