About Engineering Connections in Simulations

Engineering connections define the kinematic relationship between components (products, parts, or shapes). They define the physical positioning of these components and the types of relative motion allowed between them.

Free engineering connections are a special type of engineering connection that defines the components being connected without imposing additional physical constraints on them.

You can create a free engineering connection as part of the process of creating the simulation connection. All other types of engineering connections must be created in the Assembly Design app.

Simulation connections define the way in which forces are transferred through the components of an engineering connection. For example, a seam weld simulation connection behaves differently from a spring or bolted connection when force is applied; however, all three of these simulation connection types can be created from the same engineering connection.

Simulation connections must be based on appropriate engineering connection types and supports in the model geometry. When you create a simulation connection, you can choose from an existing engineering connection or create a free engineering connection.

When you use an existing engineering connection to create a simulation connection, the engineering connection defines the model components that are being connected. However, you might need to define new geometric supports within the selected model components if those that were selected when the engineering connection was created are not suitable for the simulation connection.

The tables below indicate the engineering connections on which you can base each type of simulation connection. In addition, free engineering connections can be used as the basis for all simulation connection types.

Simulation connection		Engineering Connections
		Spherical	Cylindrical	Revolute	Prismatic	Planar	Rigid
Coupling
Line Fastener
Point Fastener
Rigid Connection
Spring
Tie
Virtual Bolt

Connectors have relative displacements and rotations that are local to the connector. These relative displacements and rotations are referred to as components of relative motion. Available components of relative motion are displacements and rotations that are not constrained kinematically and, hence, remain available for defining material-like behavior, specifying time-dependent motion, and applying loading.

Connector		Available Components of Relative Motion		Engineering Connections
		Translation	Rotation	Spherical	Cylindrical	Revolute	Prismatic	Planar	Rigid
Beam
Bushing		U1, U2, U3	UR1, UR2, UR3
Cylindrical		U1	UR1
CV Joint
Hinge			UR1
Planar		U2, U3	UR1
Retractor
Translator		U1
U Joint			UR1, UR3
Weld
Accelerometer
Axial		U1
Cartesian		U1, U2, U3
Join
Link
Projection Cartesian		U1, U2, U3
Radial Thrust		U1, U3
Slide Plane		U2, U3
Slot		U1
Align
Cardan			UR1, UR2, UR3
Constant Velocity
Euler			UR1, UR2, UR3
Flexion-Torsion			UR1, UR2, UR3
Flow-Converter
Projection Flexion-Torsion			UR1, UR2, UR3
Revolute			UR1
Rotation			UR1, UR2, UR3
Rotation Accelerometer
Universal			UR1, UR3

When you select an engineering connection for use in a simulation connection, you might need to define new supports to complete the simulation connection.

When you reuse an engineering connection to create a simulation connection, it must join the relevant products, parts, or shapes from the model. However, the face, edge, or point supports from the engineering connection might not be suitable for the simulation connection. If the original supports meet the requirements for the new simulation connection, they are automatically included; but you can also choose new supports. If the supports are not appropriate, you must choose new supports to complete the simulation connection. In either case, the supports available for selection must be within the components defined in the engineering connection; all other model components are unavailable for selection.