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 | ||
SP1 | SP2 |
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
Combination joints combine translational and rotational joints. 2 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) |
|
SP1, SP2 | Identification numbers of
two SPOINTs which are explicitly defined directly on these fields
and are used to consider flow at each end of
JOINTGs of type SLIPRING.
8
Default = Blank (Integer > 0) |
Comments
- JOINTG element identification numbers should be unique compared to any other element in OptiStruct.
- The following table provides
information regarding currently supported Motion (MOTNJG),
Loading (LOADJG), stop/lock (PJOINTG)
degrees of freedom.
Table 1. Joint Type Motion (MOTNJG) Load (LOADJG) Stop/Lock (PJOINTG) Friction Mass Constrained degrees of freedom Elasticity (PJOINTG) RIGID (PJOINTG) DAMP (PJOINTG) CREF (PJOINTG) CID1 2.f CID2 2.f AXIAL 1 1 1 1 1 YES 1 NO NO BALL 2.a/2.b 123 NO NO RPIN 2.a2.b 123 YES NO CARTESIA 123 123 123 123 YES 123 YES NO INLINE 1 1 1 23 1 1 YES 1 YES NO INPLANE 23 1 23 23 YES 23 YES NO CARDAN 456 456 456 YES 456 YES YES ORIENT 456 YES YES REVOLUTE 4 4 4 56 4 4 YES 4 YES YES UNIVERSA 5 (twist) YES YES HINGE2.d 4 4 4 12356 4 (ELAS only) YES 4 YES YES RLINK 1 (AXIAL) NO NO RBEAM 123456 NO NO UJOINT 1235 YES YES CYLINDRI 14 14 14 2356 14 14 YES 14 YES YES TRANSLAT 1 1 1 23456 1 1 YES 1 YES YES ROTATION 456 456 456 456 456 YES 456 YES NO SLIPRING 1 1 1 1 1 1 1 12 NO NO PCART 2.e 123 123 123 123 YES 123 YES YES PFLTR 2.e 456 456 456 YES 456 YES YES BUSHING 2.e 123456 123 123456 123456 YES 123456 YES YES The following Combination Joints are available which combine Translational and Rotational Joints: AXIAORIE 1 1 1 456 1 1 YES 1 YES YES INLICARD 1456 1 23 1456 YES 1456 YES YES RLINORIE 1 (axial) 456 YES YES CARTROTA 123456 123456 123456 123456 123456 YES 123456 YES NO INPLORIE 23 23 23 1456 23 23 YES 23 YES YES CARTORIE 123 123 456 123 123 YES 123 YES YES CARTCARD 123456 123456 123456 123456 123456 YES 123456 YES NO RPINROTA 456 456 456 123 456 456 YES 456 YES NO RPINORIE 123456 YES YES RLINROTA 456 456 456 1 456 456 YES 456 YES NO RLINCARD 456 1 456 456 YES 456 YES YES RPINCARD 456 123 456 456 YES 456 YES YES AXIACARD 1456 1 1 1456 1456 YES 1456 YES YES AXIAROTA 1456 1456 1456 1456 1456 YES 1456 YES NO INLIORIE 1 1 1 23456 1 1 YES 1 YES YES INPLROTA 23456 456 456 1 23456 23456 YES 23456 YES NO INPLCARD 23456 1 23456 23456 YES 23456 YES YES - 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.
- 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.
- 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.
- CID2 for HINGE joint is mandatory only for LGDISP and only if the JOINTG grids are non-coincident.
- PCART, PFLTR, and BUSHING are currently not supported for Explicit Analysis.
- For CID1 and
CID2 columns:
- YES
- Coordinate system ID must be specified.
- NO
- Coordinate system ID is not mandatory. If an ID is specified, it is not used in the analysis.
- For additional information regarding the joint definitions, refer to JOINTG (Connectors) in the User Guide.
- JOINTG support
information:
- JOINTG is supported for Linear Static, Linear Buckling Analysis, Normal Modes Analysis, Direct and Modal Frequency Response, Random Response, Small Displacement Nonlinear Static, Large Displacement Nonlinear Static, Linear Direct Transient and Linear Modal Transient, Implicit Nonlinear Transient, Explicit Dynamics, and Inertia Relief solution sequences.
- Specific functionalities, such as loading, motion, damping, and so on,
within each type of JOINTG are generally supported
for all solutions for which JOINTG is supported
(specific support for each joint type is shown in Table 1). Exceptions
to the overall support are:
- For linear analysis, only MOTNJG with zero-motion is supported.
- For small displacement nonlinear static, MOTNJG with non-zero motion is only supported for CYLINDRICAL and AXIAL joints.
- For small displacement nonlinear static, LOADJG is supported only for CYLINDRICAL and AXIAL joints.
- SLIPRING is supported only for implicit large displacement nonlinear analysis and explicit dynamic analysis.
- For JOINTG, the following results are supported:
- JOINTF and JOINTD output requests with OPTI file format (<filename>.joint file): Force, Displacement, Reaction Forces, Viscous Damping Forces, Stop/Lock Status, and Joint Elastic force results.
- JOINTF and JOINTD output requests with H3D file format: Results are output in H3D file and are labeled as JOINTG Force, JOINTG Disp, JOINTG Reaction Forces (s), JOINTG Viscous Forces (s), JOINTG Stop and Lock Status (s), and JOINTG Elastic Forces (s).
Note:- Viscous Damping Forces are output only if damping is associated with the corresponding JOINTG (for instance, via setting PJOINTG,PROPERTY,DAMP, or setting PARAM,ALPHA2 to include Rayleigh damping).
- JOINTG Elastic force output is only supported for Implicit Nonlinear Transient Analysis.
- SLIPRING joints generate specific results (when JOINTF and JOINTD are specified). For OPTI format when SLIPRING joint is defined, there is a separate <filename>.slipring file which is generated with SLIPRING specific results. For more information on the results for SLIPRING, refer to the JOINTD and JOINTF entries.
- 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.
- Rayleigh damping is supported for JOINTG. Activate PARAM,ALPHA2 to add viscous damping to the JOINTG elements in the model.
- Flow of the SLIPRING joint can be considered using the SP1 and SP2 fields to define the corresponding SPOINTs. SPC entries (with dof 0) can be used to constrain the flow at these SPOINTs.
- 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.