The JOINT function returns component comp of a force or torque due to JOINT/id as calculated in the coordinate system of marker rm. If jflag is set to zero, the value returned is the force/torque acting on the I marker of the JOINT. If jflag is set to one, the value returned is that acting on the J marker. rm may be specified as zero if the results are desired in the global coordinate system.
Format
JOINT (id, jflag, comp, rm)
Arguments
id | An integer specifying the identification number of the joint. |
jflag | An integer flag specifying the joint connectivity marker at which the forces and torques are computed.
0 = forces and moments at the I marker
1 = forces and moments at the J marker |
comp | An integer value that specifies the component of the joint force to be returned.
1 = Magnitude of the force
2 = x component of the force
3 = y component of the force
4 = z component of the force
5 = Magnitude of the torque
6 = x component of the torque
7 = y component of the torque
8 = z component of the torque |
rm | The coordinate system in which the results are expressed. To return the results in the global coordinate system, set rm = 0. |
Examples
JOINT/1, REVOLUTE, I=46, J=23
SFORCE/1, ROTATION, I=46, J=23
, FUNCTION=-0.4*SIGN(1.0,WZ(46,23,23)*5.6*,
, (JOINT(1,0,1,23)-ABS(JOINT(1,0,4,23))))
This example illustrates how a simple dynamic friction force can be added to a revolute joint. JOINT/1 is the revolute joint to which frictional effects are to be added. 0.4 is the coefficient of friction and 5.6 is the radius of the sleeve defining the revolute joint. WZ(46,23,23) determines the direction of rotation and the negative sign indicates that the frictional moment about the z-axis of Marker 23 opposes this motion.
JOINT(1,0,1,23) determines the magnitude of the reaction force at Marker 23. JOINT(1,0,4,23) determines the component of the constraint force along the axis of the rotational of the joint. JOINT(1,0,12)-ABS(JOINT(1,0,4,23)) defines the radial load in the revolute joint (i.e., the normal force). See other
Element-specific reaction force available.