JOINTG

Format

Example

Definitions

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)	CID1	CID2
   AXIAL	1	1	1		1	1	YES	NO	NO
   BALL 2.a/2.b				123				NO	NO
   RPIN 2.a2.b				123				YES	NO
   CARTESIA	123		123		123	123		YES	NO
   INLINE	1	1		23				YES	NO
   INPLANE	23			1				YES	NO
   CARDAN	456							YES	NO
   ORIENT				456				YES	YES
   REVOLUTE	4	4		56				YES	YES
   UNIVERSA				5 (twist)				YES	YES
   HINGE2.d	4	4		12356	4 (ELAS only)		YES	YES	YES
   RLINK				1 (AXIAL)				NO	NO
   RBEAM				123456				NO	NO
   UJOINT				1235				YES	YES
   CYLINDRI	14	14	14	2356	14	14	YES	YES	YES
   TRANSLAT	1	1	1	23456	1	1		YES	YES
   ROTATION	456	456	456		456	456		YES	NO
   Example Combination Joints 2.e
   AXIAORIE	1	1	1	456				YES	YES
   INLICARD	1456	1		23				YES	YES
   RLINORIE				1 (axial) 456				YES	YES
   CARTROTA	123456	123456	123456		123456	123456		YES	NO
   INPLORIE	23	23	23	456	23	23		YES	YES
   CARTORIE	123		123	456	123	123		YES	YES
   RPINROTA	456	456	456	123	456	456		YES	NO

   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).
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.