The Fixed Joint node is used to prevent any relative motion between two components, but it can also be used for connecting reduced-order models in the context of
Component Mode Synthesis.
The components connected by a Fixed Joint are rigidly attached to each other, and the forces or moments required to restrict the relative motion can be computed. A
Fixed Joint node connects, for example, two attachments so that they form a common rigid region.
The Fixed Joint node is only available with some COMSOL products (see
www.comsol.com/products/specifications/).
Select a Source and a
Destination attachment from the lists. You can select any
Attachment or
Rigid Material in the model. In case that there is a Multibody Dynamics interface in the model, also such features as
Spur Gear,
Helical Gear,
Bevel Gear,
Worm Gear, Spur Rack, and
Helical Rack can be selected. In
Source, an additional option,
Fixed, is also available. When
Fixed is selected, the source side of the joint is fixed in space, and not connected to any modeled parts. If any
Base Motion nodes are present in a Multibody Dynamics interface, these also appear in the list for the
Source attachment. Selecting a base motion gives a behavior similar to using
Fixed, with the exception that the base now can have a nonzero prescribed displacement, velocity, or acceleration.
In large models, the list of available attachments can become long. You can then create geometric filters to narrow down the search. When the Use selection filter checkbox is selected, two subnodes named
Source Filter and
Destination Filter are added to the joint node. In these subnodes you can make graphic selections of the objects whose attachments should be shown in the
Source and a
Destination lists.
For Computed using penalty method, enter the
Penalty factor pj. The default is
solid.fxj1.Eequ*0.1*solid.diag. The exact naming of the variable depends on the tags of the nodes in the model tree.
Physics tab with Solid Mechanics or
Shell selected in the Model Builder tree:
