Block Format Keyword

/GJOINT - Gear Type Joint

Description

Defines complex (gear-type) joints. This keyword is not available for SPMD computation.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/GJOINT/type/joint_ID/unit_ID
joint_title
node_ID0	FscaleV		Mass		Inertia		node_ID1	node_ID2	node_ID3
Mass1		Inertia1		r1x		r1y		r1z
Mass2		Inertia2		r2x		r2y		r2z
Mass3		Inertia3		r3x		r3y		r3z

Field	Contents	SI Unit Example
type	Type of input (see table below for available keywords)
joint_ID	Gear type joint identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
joint_title	Gear type joint title (Character, maximum 100 characters)
node_ID0	Primary node identifier (position node) (Integer)
FscaleV	Velocity scale factor Default = 1.0 (Real)
Mass	Added mass to primary node Default = 0.0 (Real)
Inertia	Added to primary node inertia Default = 0.0 (Real)
node_ID1	Node identifier N1 (Integer)
node_ID2	Node identifier N2 (Integer)
node_ID3	Node identifier N3 - only necessary for differential gear joint. (Integer)
Mass1	Added mass to node_ID1 Default = 0.0 (Real)
Inertia1	Added to node_ID1 inertia Default = 0.0 (Real)
r1x	Local axis X component Default = 1.0 (Real)
r1y	Local axis Y component Default = 0.0 (Real)
r1z	Local axis Z component Default = 0.0 (Real)
Mass2	Added mass to node_ID2 Default = 0.0 (Real)
Inertia	Added to node_ID2 inertia Default = 0.0 (Real)
r2x	Local axis X component Default = 1.0 (Real)
r2y	Local axis Y component Default = 0.0 (Real)
r2z	Local axis Z component Default = 0.0 (Real)
Mass3	Added mass to node_ID3 Default = 0.0 (Real)
Inertia3	Added to node_ID3 inertia Default = 0.0 (Real)
r3x	Local axis X component Default = 1.0 (Real)
r3y	Local axis Y component Default = 0.0 (Real)
r3z	Local axis Z component Default = 0.0 (Real)

Type	Description
GEAR	rotational gear
DIFF	differential gear
RACK	rack and pinion

Complex (gear-type) joints belong to the family of kinematic constraints treated by a Lagrange multipliers’ method. A joint position is defined by a central node_ID0, which are connected to two or three secondary nodes. Mass and inertia must be added to all nodes. It is advisable to place the primary node in the mass center of the joint. Kinematic constraints impose relations between secondary nodes velocities.

clip0016-1

2.	Translational velocities of gear joint nodes are constrained by a rigid link relation. For the rotational DOF, a scale factor is imposed between velocities of node_ID1 and node_ID2, measured in their local coordinates. The corresponding constraint equations are the following:

starter_gjoint_eq

where, and are relative rotational velocities of node_ID1 and node_ID2 in respect of the rigid body rotational velocity.

clip0017

3.	The rotational velocities of a differential gear joint are constrained by the relations:

starter_gjoint_eq2

clip0018

4.	The rack and pinion joint allows the rotational velocity of node_ID1 to be transformed to a translational velocity of node_ID2. The constraint equations for these velocities are:

starter_gjoint_eq3

5.	This option is not available, if it is applied on:

•	a node with a null mass

•	a node with a null inertia (except in case of node_ID2 of a rack type GJOINT)

/GJOINT

/GJOINT

/GJOINT

/GJOINT - Gear Type Joint

/GJOINT/type/joint_ID/unit_ID

joint_title

See Also: