PJOINTG
Bulk Data Entry Defines the properties for a joint connection between two grids via the JOINTG Bulk Data Entry.
Format
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| PJOINTG | PID | ||||||||
| If PROPERTY=STOP or LOCK | |||||||||
| PROPERTY | DOF | LB | UB | TYPE | LDOF | ||||
| If PROPERTY=ELAS | |||||||||
| PROPERTY | DOF | ||||||||
| STIFFNESS | |||||||||
| If PROPERTY=NELA | |||||||||
| PROPERTY | DOF | ||||||||
| F1 | U1 | ||||||||
| etc | etc | ||||||||
| Fi | Ui | ||||||||
| If PROPERTY = RIGID | |||||||||
| PROPERTY | DOF | ||||||||
| If PROPERTY=DAMP | |||||||||
| PROPERTY | DOF | ||||||||
| DAMP | |||||||||
| If PROPERTY=CREF | |||||||||
| PROPERTY | DOF | ||||||||
| CREF | |||||||||
Example
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| PJOINTG | 2 | ||||||||
| STOP | 2 | 2.0 | 4.0 |
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
|---|---|---|---|---|---|---|---|---|---|
| PJOINTG | 2 | ||||||||
| ELAS | 123 | ||||||||
| 200.0 |
Definitions
| Field | Contents | SI Unit Example |
|---|---|---|
| PID | Joint property
identification number. No default (Integer > 0) |
|
| PROPERTY | Property type applied to
the corresponding degrees of freedom in the joint.
No default |
|
| If PROPERTY=STOP or LOCK | ||
| DOF | Degree of freedom which
the specified property applies. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| LB | Lower bound of the degree
of freedom at which the specified property is activated. Lower bound
implies a negative value should be specified which indicates the
relative displacement the grid points associated with a joint are
allowed to move towards each other in the specified
DOF before the
STOP/LOCK conditions are
applied. Default = blank (Real < 0.0) |
|
| UB | Upper bound of the degree
of freedom at which the specified property is activated. Upper bound
implies a positive value should be specified which indicates the
relative displacement the grid points associated with a joint are
allowed to move away from each other in the specified
DOF before the
STOP/LOCK conditions are
applied. Default = blank (Integer > 0.0) |
|
| TYPE | Identifies the
displacement value interpretation for bounds of
STOP/LOCK options.
|
|
| LDOF | If one of the degrees of
freedom locks, then by default the other degrees of freedom of the
joint also lock. However, if any degrees of freedom are specified on
the LDOF field, then only these degrees of
freedom lock if any degree of freedom enters locking
phase. Default = blank (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| If PROPERTY=ELAS | ||
| DOF | Degree(s) of freedom to
which the stiffness value applies. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| STIFFNESS | Value of stiffness for the
specified degree(s) of freedom. No default (Real) |
|
| If PROPERTY=NELA | ||
| DOF | Degree(s) of freedom to
which the stiffness value applies. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| Fi, Ui | Force-Displacement values
for the degree(s) of freedom associated with the specified DOF. No default (Real) |
|
| If PROPERTY=RIGID | ||
| DOF | Degree(s) of freedom to
which are rigidly connected. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| If PROPERTY=DAMP | ||
| DOF | Degree(s) of freedom to
which damping value is applied. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| DAMP | Damping value. No default (Real) |
|
| If PROPERTY=CREF | ||
| DOF | Degree(s) of freedom to
which the constitutive reference values are applied. No default (1 ≤ Integer ≤ 6, single or multiple integers can be specified with no embedded blanks) |
|
| CREF | Constitutive reference
values. No default (Real) |
|
Comments
- PJOINTG entries can be referenced on the JPID field of the JOINTG Bulk Data Entry to define corresponding joint properties.
- The LB and
UB values are interpreted based on the following
considerations.
- The TYPE field on the PJOINTG entry. If TYPE field is blank, then the LB and UB fields identify the lower and upper bounds of the relative motion of the joint
- The coordinate systems defined on the JOINTG entry
- The G1 and G2 grid points of the JOINTG entry
- The ELAS and
NELA properties are supported for AXIAL,
CARTESIAN, TRANSLATOR,
CYLINDRICAL, and ROTATION joints.
For HINGE joint, only ELAS is currently supported.
The RIGID property is only supported for AXIAL, CARTESIAN, TRANSLATOR, CYLINDRICAL, and ROTATION joints.
The ELAS continuation line and the associated stiffness can be repeated if different stiffness values are required for the each of the different degrees of freedom for the same joint.
The NELA continuation line and the associated force-displacement curve can be repeated, if different curves are required for the each of the different degrees of freedom for the same joint. Similarly, the RIGID continuation line can be repeated. The different degrees of freedom of a joint can have linear, nonlinear elasticity, or RIGID definitions.
The CREF continuation line is supported for all joints listed on the JOINTG Bulk Data Entry.
- CREF allows you to specify reference positions of the joints where the force and/or moment is zero, if such a position is not the same as the initial position. For such joints, you can specify up to six values of constitutive reference (depending on the joint type). These values influence multiple joint behaviors, including elastic behavior of joints (ELAS) and STOP/LOCK(with TYPE=Default), along the corresponding DOFs. CREF is not supported with MOTNJG. CREG is also not supported for STOP/LOCK if TYPE=1 is set. CREF is currently only supported for large displacement nonlinear static, implicit large displacement nonlinear transient analysis, and explicit analysis.
- The OptiStruct joints defined using JOINTG are different from the Multibody Dynamics (OS-MBD) joints which are defined using the JOINT Bulk Data Entry with OptiStruct-MotionSolve integration.
- The analysis support information for PJOINTG is as
follows:
- ELAS, RIGID, DAMP, and CREF
- All analysis types except Explicit Dynamic Analysis.
- NELA, STOP, LOCK
- Nonlinear Static and Nonlinear Transient Analysis for small and large displacement analysis cases.