COMSOL 6.2 - Prismatic Joint

Use the node for 2D and 3D components to create a joint between two components such that they are free to translate relative to each other along the joint axis.

The Constraints, Locking, Spring and Damper, Prescribed Motion, Applied Force and Moment, and Friction subnodes can be added to modify the properties of the joint.

Select a and a attachment from the lists. You can select any Attachment, Rigid Material, Spur Gear, Helical Gear, Bevel Gear, Worm Gear, Spur Rack, or Helical Rack that is defined for the model. In an additional option, , is also available. When 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 the model, these also appear in the list for the attachment. Selecting a base motion gives a behavior similar to using , 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 check box 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 and a lists.

The center of joint is the point about which displacements and rotations of source and destination boundaries are interpreted. Select an option from the list — , , , or .

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For and , the joint is located at the centroid of the selection giving the source or destination, respectively.

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For select an — , , or . The available choices depend on geometrical dimension. The center of joint is located at the centroid of the selected entities. As a special case, you can select a single point, and thus use that point as center of joint.

	When chosen, a default Center of Joint: Boundary, Center of Joint: Edge, or Center of Joint: Point subnode is automatically added.

Select the check box to add an optional offset vector to the definition of the center of rotation. Enter values for the offset vector Xoffset.

The center of rotation used is the sum of the vector obtained from any of the input methods and the offset vector.

The axis of joint is the axis along which the relative motion is allowed. Select an option from the list — , , or .

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For enter a value or expression for e0. The default is (1, 0, 0). The direction is specified in the selected coordinate system.

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For an edge can be selected on the Joint Axis subnode, which is added automatically. The vector from the first to the last end of the edge is used to define the joint axis. Any edge in the model can be used. Select the check box to reverse the direction of the joint axis.

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For the joint axis is formed using the selected coordinate system. With you select the axis (first, second, or third) that is parallel to the joint axis.

Select an option from the list to determine whether the joint should be fully rigid or elastic — or . For , the properties of an elastic joint are given in the Joint Elasticity subnode, which is added automatically.

Select an option from the list to use the method of computation for the forces and moments — , , , , or . For , enter the pj. The default is (mbd.prj1.Eequ*(0.1*mbd.diag)). The exact naming of the variable depends on the tags of the nodes in the model tree.

Select — (default), , or , to choose how to group the dependent variables added by the feature in the solver sequence.