JOINT

Bulk Data Entry Defines a joint for Multibody Dynamics.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
JOINT JID JTYPE G1 G2 X3, G3 Y3 Z3 blank
X4, G4 Y4 Z4

Example 1

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
JOINT 3 BALL 345 231

Example 2

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
JOINT 4 UNIV 456 899 0.0 0.0 1.0
399

Definitions

Field Contents SI Unit Example
JID Unique joint identification number.

(Integer > 0)
JTYPE Joint type.
BALL
All translations are fixed; all rotations are free.
FIX
All translations and rotations are fixed.
REV (Revolute)
Rotation about a single selected axis is free; other rotations and translations are fixed.
TRANS (Translational)
Translation along a single selected axis is free; other translations and rotations are fixed.
CYL (Cylindrical)
Translation along and rotation about a single selected axis is free; other translations and rotations are fixed.
UNIV (Universal)
Rotations about two selected perpendicular axes are free; translations and other rotations are fixed.
CV (Constant Vel)
Rotations about two selected axes are equal and opposite; translations and other rotations are fixed.
PLANAR
Translations on a plane defined by a selected normal vector and the rotation about that normal vector are free, out-of-plane translations and rotations are fixed.
INLINE
Translation along a single selected axis and all rotations are free; other translations are fixed.
PERP (Perpendicular)
Two perpendicular axes are selected that are always to remain perpendicular. Therefore, rotations about both selected axes and all translations are free. Rotation about the cross-product of the two selected vectors is fixed.
PARA (Parallel Axes)
Two parallel axes are selected that are always to remain parallel. Therefore, rotations about the selected parallel axes and all translations are free; other rotations are fixed.
INPLANE
Two perpendicular vectors are selected that describe a plane. Out-of-plane translations are fixed; all other translations and rotations are free.
ORIENT
All rotations are fixed; all translations are free.
G1, G2 Geometric grid point identification number. Used to identify the bodies to be connected and, for many JTYPEs, the location of the joint.

G1 and G2 identify the bodies being joined and must; therefore, belong to different bodies.

(Integer > 0)
X3, Y3, Z3 First orientation vector of the joint.

(Real)
G3 Grid point identification number to optionally supply X3, Y3, Z3 in conjunction with either G1 or G2 (depending on the JTYPE).

(Integer > 0)
X4, Y4, Z4 Second orientation vector of the joint.

(Real)
G4 Grid point identification number to optionally supply X4, Y4, Z4 in conjunction with G2.

(Integer > 0)

Comments

  1. Joints are only valid in a multibody solution sequence.
  2. Definition of the different joint types:
    JTYPE Required Fields Joint Orientation
    BALL G1, G2 G1 and G2 must coincide.
    FIX G1, G2 G1 and G2 must coincide.
    REV G1, G2, and either X3, Y3, Z3 or G3 G1 and G2 must coincide.

    The selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.
    TRANS G1, G2, and either X3, Y3, Z3 or G3 G1 and G2 must be along the joint axis.

    The selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.
    CYL G1, G2, and either X3, Y3, Z3 or G3 G1 and G2 must be along the joint axis.

    The selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.
    UNIV G1, G2, and either X3, Y3, Z3 or G3 and either X4, Y4, Z4 or G4 G1 and G2 must coincide.

    The first selected (cross pin) axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.

    The second selected (cross pin) axis is defined by the vector X4, Y4, Z4 or alternatively the vector from G2 to G4.

    The selected axes must be perpendicular.
    CV G1, G2, and either X3, Y3, Z3 or G3 and either X4, Y4, Z4 or G4 G1 and G2 must coincide.

    The first selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.

    The second selected axis is defined by the vector X4, Y4, Z4 or alternatively the vector from G2 to G4.
    PLANAR G1, G2, and either X3, Y3, Z3 or G3 G1 and G2 must be in the joint plane.

    The vector X3, Y3, Z3 or the vector from G1 to G3 will define the normal to the plane.
    INLINE G1, G2, and either X3, Y3, Z3 or G3 G1 and G2 must be along the joint axis.

    The selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G2 to G3.
    PERP G1,G2 and either X3, Y3, Z3 or G3 and either X4, Y4, Z4 or G4 The first selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.

    The second selected axis is defined by the vector X4, Y4, Z4 or alternatively the vector from G2 to G4.

    The selected vectors must be perpendicular to one another.
    PARA G1,G2 and either X3, Y3, Z3 or G3 and either X4, Y4, Z4 or G4 The first selected axis is defined by the vector X3, Y3, Z3 or alternatively the vector from G1 to G3.

    The second selected axis is defined by the vector X4, Y4, Z4 or alternatively the vector from G2 to G4.

    The selected vectors must be parallel to one another.
    INPLANE G1,G2 and either X3, Y3, Z3 or G3 and either X4, Y4, Z4 or G4 The first selected vector is defined by X3, Y3, Z3 or alternatively the vector from G2 to G3.

    The second selected vector is defined by X4, Y4, Z4 or alternatively the vector from G2 to G4.

    The selected vectors must be perpendicular to one another.
    ORIENT G1, G2
  3. The Multibody Dynamics (OS-MBD) joints which are defined using the JOINT entry with OptiStruct-MotionSolve integration are different from the OptiStruct joints defined using JOINTG.
  4. This card is represented as a joint element in HyperMesh.