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Reference Guide
This manual provides a detailed list of all the input keywords and options available in Radioss.
LS-DYNA Input
This manual provides a list of LS-DYNA input files available in Radioss.
*CONSTRAINED
*CONSTRAINED_JOINT
LS-DYNA Input Interface KeywordDefine a joint between two rigid bodies.

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Radioss^® is a leading explicit finite element solver for crash and impact simulation.
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This manual provides a detailed list of all the input keywords and options available in Radioss.
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  Current Radioss format uses the 12x extension format.
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  This format allows running either Starter or Engine with the same file.
- New Keywords in 2025
  New and modified features in Radioss.
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  This manual provides a list of all the model definition keywords and options available in Radioss.
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  This manual provides a list of all the solution definition keywords and options available in Radioss.
- LS-DYNA Input
  This manual provides a list of LS-DYNA input files available in Radioss.
  - *AIRBAG
  - *BOUNDARY
  - *CONSTRAINED
    - *CONSTRAINED_EXTRA_NODES
      LS-DYNA Input Interface KeywordDefine extra nodes to add to a rigid body.
    - *CONSTRAINED_GENERALIZED_WELD_SPOT
      LS-DYNA Input Interface KeywordDefine a connection between 2 nodes with a possible force-based failure model.
    - *CONSTRAINED_INTERPOLATION
      LS-DYNA Input Interface KeywordDefines an RBE3 element.
    - *CONSTRAINED_JOINT
      LS-DYNA Input Interface KeywordDefine a joint between two rigid bodies.
    - *CONSTRAINED_JOINT_STIFFNESS
      LS-DYNA Input Interface KeywordDefine a stiffness, stop angles and friction for rotational DOFs of a joint between two rigid bodies.
    - *CONSTRAINED_NODAL_RIGID_BODY
      LS-DYNA Input Interface KeywordThis keyword defines a nodal rigid body.
    - *CONSTRAINED_NODAL_SET
      LS-DYNA Input Interface KeywordDefines a translational constraint to a set of nodes in the global coordinate system. There is no rotational coupling.
    - *CONSTRAINED_RIGID_BODIES
      LS-DYNA Input Interface KeywordDefine rigid bodies assembly.
    - *CONSTRAINED_SPOTWELD
      LS-DYNA Input Interface KeywordDefine a connection between 2 nodes with a possible force based failure model.
  - *CONTACT
  - *CONTROL
  - *DAMPING
  - *DATABASE
  - *DEFINE
  - *ELEMENT
  - *EOS
  - *HOURGLASS
    LS-DYNA Input Interface KeywordDefine solid and hourglass formulation for 8-node solid elements.
  - *INCLUDE
  - *INITIAL
  - *INTEGRATION_SHELL
    LS-DYNA Input Interface KeywordDefine user-defined through the thickness integration rules for the composite shell element.
  - *KEYWORD
    LS-DYNA Input Interface KeywordThis keyword should always be the first card of the input file. Optionally used with *CONTROL_UNITS card to specify model units.
  - *LOAD
  - *MAT
  - *NODE
    LS-DYNA Input Interface KeywordDefines a node number and nodal coordinates in the global coordinate system.
  - *PART
    LS-DYNA Input Interface KeywordDefines a part, which combines material and property information.
  - *RIGIDWALL
  - *SECTION
  - *SET
- Multi-Domain
  This manual contains the description of the keywords for the Radioss Multi-Domain.
- Obsolete Keywords
  Keywords that are still supported, but no longer maintained (*) are considered obsolete.
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This manual provides detailed information about the theory used in the Altair Radioss Solver.
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This manual describes the interface between Altair Radioss and user subroutines.

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*CONSTRAINED_JOINT

LS-DYNA Input Interface KeywordDefine a joint between two rigid bodies.

Format


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
*CONSTRAINED_JOINT_TYPE_{OPTION}

If OPTION = ID, insert the following line.


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
`JID`	`Title`


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
`node_ID`₁	`node_ID`₂	`node_ID`₃	`node_ID`₄	`node_ID`₅	`node_ID`₆

Definition


Field	Contents	SI Unit Example
`TYPE`	CYLINDRICAL Cylindrical joint between node `node_ID`₁ and `node_ID`₂ and along direction (`node_ID`₁, `node_ID`₃). REVOLUTE Revolute joint between node `node_ID`₁ and `node_ID`₂ and along direction (`node_ID`₁,`node_ID`₃). SPHERICAL Cylindrical joint between node `node_ID`₁ and `node_ID`₂. LOCKING Rigid joint node `node_ID`₁ and `node_ID`₂. TRANSLATIONAL Translational joint between node `node_ID`₁ and `node_ID`₂ and along direction (`node_ID`₁, `node_ID`₃). UNIVERSAL Universal joint between node `node_ID`₁ and `node_ID`₂ and along local coordinate system (`node_ID`₁, `node_ID`₃, `node_ID`₄). PLANAR Planar joint between node `node_ID`₁ and `node_ID`₂ and along local coordinate system (`node_ID`₁, `node_ID`₃, `node_ID`₄) No default
`OPTION`	ID.
`JID`	Joint ID. (Integer)
`Title`	Joint title. (Character, maximum 70 characters)
`node_ID`₁	Node identifier 1 for joint attached to rigid body A. (Integer)
`node_ID`₂	Node identifier 2 for joint attached to rigid body B. (Integer)
`node_ID`₃	Node identifier 3 for joint attached to rigid body A. (Integer)
`node_ID`₄	Node identifier 4 for joint attached to rigid body B. (Integer)
`node_ID`₅	Node identifier 5 for joint attached to rigid body A. (Integer)
`node_ID`₆	Node identifier 6 for joint attached to rigid body B. (Integer)

Comments

This keyword maps to /SPRING, /PROP/TYPE45 (KJOINT2), and /PART.
It is recommended to have node_ID₁ and node_ID₂ at the same initial position.