Contacts between steel connection plates

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The standard penalty method is recommended for modeling contact between plates. If penetration of a node into an opposite contact surface is detected, penalty stiffness is added between the node and the opposite plate. The penalty stiffness is controlled by a heuristic algorithm during the nonlinear iteration to get a better convergence. The solver automatically detects the penetration point and solves the contact force distribution between the penetrated node and nodes on the opposite plate. It allows the creation of contact between different meshes, as shown. The advantage of the penalty method is the automatic assembly of the model. The contact between the plates has a major impact on the redistribution of forces in connection.

IDEA StatiCa Connection theoretical background for the advanced structural design of steel connections. Description of contacts and their application in CBFEM. Structural design of welded and bolted steel connections.

An example of separation of plates in contact between the web and flanges of two overlapped Z sections purlins

It is possible to add contact between

  • two surfaces,
  • two edges,
  • edge and surface.

An example of edge-to-edge contact between the seat and the end plate

An example of edge-to-surface contact between the lower flange of the beam and the column flange

The stresses in contacts may be visualized, and the values are shown in the check table of plates. However, the contact stresses are only informative and are not used in any check. Also, the through-thickness stress of shell elements is not considered. 

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