Joints
Joint entities define a connection between two rigid bodies. Joint elements reference property and orientation information.
Create Joint Elements
Joint elements are commonly used to connect two parts to define a relative motion with joint specific degrees of freedom.
Joint elements are config 22 and are displayed with lines between the appropriate nodes and the letter J between nodes 1 and 3 of the element. The type of joint element controls the number of nodes contained in the element. The type also controls the orientation information formats available.
Figure 1.
In the OptiStruct interface, click the arrow next to the Interactions tool set name and select Joints.
OptiStruct Profile
Enables the automatic creation of a joint element using the PJOINTG property.
- Joint Type
- Select the type of joint connection between two grids.
- Node Selection
- Two nodes must be selected to define the joint connection.
- Orientation System
- Coordinate system identification number for the first grid point GID1 and second grid point GID2.
- Property
- PJOINTG property selection.
Radioss
Enables the automatic creation of joint elements using the KJOINT2 property, as well as the attachments to the Rigid Bodies. It also allows for the creation of the /CYL_JOINT keyword for the cylindrical joint type.
- Joint Type
- Select the type of joint connection between Rigid A and Rigid B.
- Rigid A and Rigid B
- Selection of /RBODY between which the joint will be created.
- Nodes
- The minimum requested nodes to be selected to define the joint element. The number of nodes depends on the selected joint type. Additional joint nodes which are coincident to the selected nodes are automatically created by the tool.
- Create new /PART
- When this option is ON, it automatically creates a new PART in which the joint element is created. If the option is OFF, an existing component needs to be selected.
On creation of the joint, a Spring element is created and a Property of type KJOINT2 is created and assigned to the PART if the option “Create new /PART” is ON. Also, the selected /RBODIES in Rigid A and Rigid B are automatically updated with the nodes of the joint element.
LS-DYNA
Enables the automatic creation of *CONSTRAINED_JOINT keywords, as well as the attachment between the joint element and the two rigid parts.
- Joint Type
- Select the type of joint connection between Rigid A and Rigid B parts.
- Rigid A and Rigid B
- Selecting a Component allows the selection of a rigid part having *MAT_RIGID assigned. Selecting an Element allows the selection of a *CONSTRAINED_NODAL_RIGID_BODY.
- Nodes
- The minimum requested nodes to be selected to define the joint element. The number of nodes depends on the selected joint type. Additional joint nodes which are coincident to the selected nodes are automatically created by the tool.
- Local Option
- Activates the LOCAL option on the *CONSTRAINED_JOINT keyword.
- Failure Option
- Activates the FAILURE option on the *CONSTRAINED_JOINT keyword.
When Rigid A or Rigid B is a rigid part, *CONSTRAINED_EXTRA_NODES_NODE keywords are created to link the corresponding joint nodes to the rigid part.
When Rigid A or Rigid B is a nodal rigid body element, this element is automatically updated with the corresponding joint nodes added in the secondary set of the element.
PAM-CRASH Profile
Enables the automatic creation of all types of FE Joints (KJOIN, JOINT, MTOJNT, MBSYS_JOINT).
- Solver Keyword
- Select Type of FE Joint Keyword for the solver.
- Joint Type
- Select the category of joint to be created under that Solver Joint Keyword.
- Node Selection
- Two nodes selection is the minimum requirement for creation of the Joint. These nodes define the two extremities of the joint in the case of finite element rigid bodies. Also, along with two nodes, you can optionally select Rigid A or/and B if the joint needs to be created between Rigid bodies. Upon creation of the Joint, these mandatory two nodes are added to the respective Rigid bodies as secondary nodes.
- Create new /PART
- When this option is ON, then upon creation of the Joint, a new component with card image /PART is created with corresponding the part type. Also, MAT 230 is created and assigned to that PART in the preceding example. When this option is toggled OFF, then you can select the component in which the joint element is created.