Edge to Edge
Add an Edge to Edge node to connect two shell edges that are geometrically disjoint. It is assumed that the edges are parallel. The connection between corresponding points on the two edges can be rigid or flexible.
This connection is useful in, for example, the following situations:
If there is no good match between two edges, you can as an alternative use the Edge to Boundary coupling.
Coordinate System Selection
Select the coordinate system to use for specifying the stiffness in the case of a flexible connection. From the Coordinate system list select from:
Global coordinate system (the standard global coordinate system).
Local edge system
Face Defining the Orientations
This setting is used in conjunction with Local edge system and Shell Local System. When the connection is used for an edge which is shared between boundaries, the coordinate system can be ambiguous. Select the boundary which should define the edge system. The default is Use face with lowest number.
Connection Settings
Select a MethodRigid or Flexible.
For Rigid, the coupling between the two edges is rigid in a pointwise manner. Every node on the destination edge is coupled by a virtual rigid bar to the nearest point on the source edge. This does not imply that the whole edge is rigid. Such a coupling can be obtained using a Rigid Connector.
For Rigid, select for both the source and destination sides of the connection the Connected location Top surface, Midsurface (default), or Bottom surface.
For Flexible, you supply a stiffness matrix, connecting the corresponding points on the source and destination edges. The stiffness coefficients are given per unit length along the edge. Input fields for the matrices ku,L and kΘ,L are always shown.
Select Translational-rotational coupling to show input fields for the coupling matrices kuΘ,L and kΘu,L. In 2D axisymmetry, most elements of these matrices are by definition zero. Only elements which can be nonzero are shown; these are elements 13 and 23 for kuΘ,L, and elements 31 and 32 for kΘu,L.
The stiffness relation can be expressed as
Here, f and m are the forces and moments per unit length acting on the destination side, and Δu is the difference between the destination side displacements and the source side displacements. Similarly, ΔΘ is the difference between the destination side rotations and the source side rotations. All vectors are expressed in the selected coordinate system.
Optionally, you can enter a Mass per unit length, ρu,L. This can for example be the mass of a not modeled weld.
In order to ascertain that the two edges are parallel, a certain tolerance is used when comparing the angles between them. You can modify this tolerance. Select the Connection toleranceAutomatic or User defined. For, Δ, enter the maximum angle between the edges.
Select the Weld verification check box to compute forces and stresses per unit length and their average along the weld.
Select the Weld type Double-sided fillet, Single-sided fillet (top), Single-sided fillet (bot), or Butt. For any of the options, enter the Throat size a, the Allowable equivalent stress , and the Allowable normal stress (perpendicular to the weld) .
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box. The information in this section is only used if Method is set to Rigid.
In the COMSOL Multiphysics Reference Manual:
Location in User Interface
Context Menus
Ribbon
Physics tab with Shell selected: