JOINTG

Bulk Data Entry Defines a joint connection between two grids.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
JOINTG JID JPID JTYPE GID1 CID1 GID2 CID2    

Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
JOINTG 2 3 UNIVERSA 234 1 2445 1    

Definitions

Field Contents SI Unit Example
JID Joint element identification number.

No default (Integer > 0)

 
JPID Property identification number of PJOINTG.

Default = Blank (Integer > 0)

 
JTYPE Joint type. 2
UNIVERSA
Universal joint
BALL
Ball joint
REVOLUTE
Revolute joint
AXIAL
Axial joint
CARTES
Cartesian joint
CARDAN
Cardan joint
INPLANE
In-plane joint
INLINE
In-line joint
ORIENT
Orientation joint
HINGE
Hinge joint
RLINK
Rigid link joint
RPIN
Rigid pin joint
RBEAM
Rigid beam joint
UJOINT
Universal connection with rigid pin joint
CYLINDRI
Cylindrical joint
TRANSLAT
Translator joint
ROTATION
Rotation joint

Combination Joints:

Any combination of the following translational joints: AXIA, INLI, RLIN, CART, INPL, RPIN can be assembled with any of the rotational joints: ORIE, CARD, ROTA to create a combination joint.
Note: translational joints always should be listed first, followed by the rotational joint (as shown in the examples below, and in the table).
AXIAORIE
Combination of Axial and Orient joints.
INLICARD
Combination of Inline and Cardan joints.
RLINORIE
Combination of Rigid Link and Orient joints.
CARTROTA
Combination of Cartesian and Rotation joints.
INPLORIE
Combination of In-plane and Orientation joints.
CARTORIE
Combination of Cartesian and Orientation joints.
RPINROTA
Combination of Rigid Pin and Rotation joints.
CARTCARD
Combination of Cartesian and Cardan joints.

No default

 
GID1 Grid Point identification number of the first grid.

No default (Integer > 0)

 
CID1 Coordinate system identification number for the first grid point GID1.

Default = blank (Integer > 0)

 
GID2 Grid Point identification number of the second grid.

No default (Integer > 0)

 
CID2 Coordinate system identification number for the second grid point GID2.

Default = blank (Integer > 0)

 

Comments

  1. JOINTG element identification numbers should be unique compared to any other element in OptiStruct.
  2. The following table provides information regarding currently supported Motion (MOTNJG), Loading (LOADJG), stop/lock (PJOINTG) degrees of freedom.
    Joint Type Motion (MOTNJG) Load (LOADJG) Stop/Lock (PJOINTG) Constrained degrees of freedom Elasticity (PJOINTG) RIGID (PJOINTG) DAMP (PJOINTG) CREF (PJOINTG) CID1 CID2
    AXIAL 1 1 1 1 1 YES YES NO NO
    BALL 2.a/2.b 123       YES NO NO
    RPIN 2.a2.b       123       YES YES NO
    CARTESIA 123 123 123 123 YES* YES YES NO
    INLINE 1 1 23       YES YES NO
    INPLANE 23 1       YES YES NO
    CARDAN 456       YES YES NO
    ORIENT 456       YES YES YES
    REVOLUTE 4 4 56       YES YES YES
    UNIVERSA 5 (twist)       YES YES YES
    HINGE2.d 4 4   12356 4 (ELAS only)   YES YES YES YES
    RLINK       1 (AXIAL)       YES NO NO
    RBEAM       123456       YES NO NO
    UJOINT       1235       YES YES YES
    CYLINDRI 14 14 14 2356 14 14 YES YES YES YES
    TRANSLAT 1 1 1 23456 1 1 YES* YES YES YES
    ROTATION 456 456 456   456 456 YES* YES YES NO
    Example Combination Joints 2.e
    AXIAORIE 1 1 1 456 1 1 YES* YES YES YES
    INLICARD 1456 1   23       YES YES YES
    RLINORIE       1 (axial) 456       YES YES YES
    CARTROTA 123456 123456 123456   123456 123456 YES* YES YES NO
    INPLORIE 23 23 23 1456 23 23 YES* YES YES YES
    CARTORIE 123   123 456 123 123 YES* YES YES YES
    RPINROTA 456 456 456 123 456 456 YES* YES YES NO
    CARTCARD 123456 123456 123456   123456 123456 YES* YES YES NO

    *Supported only for Explicit Dynamic Analysis (NLEXPL).

    1. For BALL joint, there is no relative translation between the two degrees of freedom in the basic system. Local systems should not be defined for the BALL joint and will not be used if specified.
    2. For RPIN joint, there is no relative translation between the grids in the local system defined on CID1 (this is where RPIN differs from BALL joint).
      Note: For any local system defined on a grid for the joints, the local systems move/rotate along with the grids on which they are defined.
      Therefore, even though from the perspective of the basic system, there may seem to be relative translation between the grids in RPIN joint, there will not be any relative translation between the grids in the local CID1 which moves/rotates with grid GID1.
    3. Constrained degrees of freedom are degrees of freedom of each grid of the joint that allow no relative motion with each other in that dof. For example, in BALL joint, no relative motion is allowed in degrees of freedom 123 between the two grids of the joint.
    4. CID2 for HINGE joint is mandatory only for LGDISP and only if the JOINTG grids are non-coincident.
    5. Combination joints listed in the table above are examples. Any combination of the following translational joints: AXIA, INLI, RLIN, CART, INPL can be assembled with any of the rotational joints: ORIE, CARD, ROTA to create a combination joint. The translational joints always should be listed first, followed by the rotational joint (as shown in the examples).
    6. In the case of Explicit Dynamic Analysis, MOTNJG and LOADJG are not supported. STOP/LOCK, DAMP, ELASTICITY and RIGID options are supported for certain joints, as summarized above.
  3. For additional information regarding the joint definitions, refer to JOINTG (Connectors) in the User Guide.
  4. JOINTG support information:
    1. JOINTG is supported for Linear Static, Small Displacement Nonlinear Static, Large Displacement Nonlinear Static, Direct Transient, and Inertia Relief solution sequences.
    2. MOTNJG (zero and non-zero motion) and LOADJG are supported for all relevant joints and solution sequences for which JOINTG is supported (with some exceptions). For linear analysis, only MOTNJG with zero-motion is supported. MOTNJG with non-zero motion is only supported for CYLINDRICAL and AXIAL joints in SMDISP. LOADJG is supported only for CYLINDRICAL and AXIAL joints in SMDISP.
    3. STOP/LOCK on PJOINTG entry is only supported for LGDISP and SMDISP Nonlinear Static Analysis (NLSTAT).
  5. Force, Displacement, Reaction Forces, Viscous Damping Forces, and Stop/Lock Status results for JOINTG are output to the <filename>.joint file when OPTI file format is chosen on STRESS and STRAIN I/O Entries, respectively. If H3D file format is requested on STRESS and STRAIN entries, then the corresponding results are labeled as JOINTG Force and JOINTG Disp., JOINTG Reaction Forces (s), JOINTG Viscous Forces (s), and JOINTG Stop and Lock Status (s), respectively. Note that Viscous Damping Forces are output only if the PROPERTY field on PJOINTG is set to DAMP.
  6. Over-constraint check information is printed in the .out file when JOINTG degrees of freedom are over-constrained. This is currently only available when the JOINTG entry is in the model, and if multiple constraints apply on the same degree of freedom. These multiple enforced constraints create a loop, which is now printed in the .out file, allowing you to identify such grid points. In Figure 1, a loop can be seen as:
    2003 → 9003 → 1003 → 2003


    Figure 1.
  7. The OptiStruct joints defined using JOINTG are different from the Multibody Dynamics (OS-MBD) joints which are defined using the JOINT entry with OptiStruct-MotionSolve integration.