NodeGenericData

A node containing a number of data (history) variables. Use this node e.g. for contact (active set), friction or plasticity (history variables).

Interface

Provides: GenericData
Objects that take this node: ObjectConnectorRigidBodySpringDamper, ObjectConnectorTorsionalSpringDamper, ObjectConnectorCoordinateSpringDamperExt, ObjectConnectorRollingDiscPenalty, ObjectContactConvexRoll, ObjectContactCoordinate, ObjectContactCircleCable2D, ObjectContactFrictionCircleCable2D, ObjectContactSphereSphere, ObjectContactSphereTorus, ObjectContactSphereTriangle, ObjectContactCurveCircles, ObjectJointSliding, ObjectJointSliding2D

Parameters

The parameters of the item; in a dictionary, its type is ‘GenericData’:

name	type	default	description
name	String	‘’	node’s unique name
initialCoordinates	Vector	[]	(symbol: \(\xv\cIni = [x_0,\,\ldots,\,x_{n_c}]\tp\cIni\)) initial data coordinates
numberOfDataCoordinates	UInt	0	(symbol: \(n_c\)) number of generic data coordinates (history variables)
visualization	VNodeGenericData		parameters for visualization of item

Visualization parameters

VNodeGenericData has no parameters.

Drawing

The item draws nothing.

Output variables

Available as OutputVariableType in sensors, Get...Output() and other functions:

output variable	symbol	description
Coordinates	\(\xv\cConfig = [x_0,\,\ldots,\,x_{nc}]\tp\cConfig\)	data coordinates (history variables) vector of node

Detailed description

Coordinates

A number of data coordinates, numberOfDataCoordinates, whose meaning is defined by the object that uses the node: the contact state of a contact object, the stick or slip state and the last position of friction, plastic strains. Data coordinates are no unknowns of the equations of motion; the object updates them between steps, in its post Newton step.

Action on the equations of motion

None directly: the data coordinates change the equations of the object that owns them, e.g. by switching a contact on or off.

Mini example

#data coordinates hold a state that is no degree of freedom and that the object updates after each step:
#here the limit stop of a connector, which a mass is pushed against
node = mbs.AddNode(Node1D(referenceCoordinates=[0]))
mbs.AddObject(ObjectMass1D(nodeNumber=node, mass=1))
mMass = mbs.AddMarker(MarkerNodeCoordinate(nodeNumber=node, coordinate=0))
mGround = mbs.AddMarker(MarkerNodeCoordinate(nodeNumber=nGround, coordinate=0))
nData = mbs.AddNode(NodeGenericData(numberOfDataCoordinates=3, initialCoordinates=[0,0,0]))
mbs.AddObject(ObjectConnectorCoordinateSpringDamperExt(markerNumbers=[mGround, mMass], nodeNumber=nData,
              damping=20, useLimitStops=True, limitStopsLower=-1, limitStopsUpper=0.05,
              limitStopsStiffness=1e4, limitStopsDamping=100))
mbs.AddLoad(LoadCoordinate(markerNumber=mMass, load=10))

mbs.Assemble()
mbs.SolveDynamic()

#the mass rests at the stop, pressed into it by F/k_limits
exu.sys['testResult'] = mbs.GetNodeOutput(node, exu.OutputVariableType.Coordinates) #0.05+0.001

Relevant Examples (Ex) and TestModels (TM) with weblink to github: ANCFcontactCircle.py (Ex), ANCFcontactCircle2.py (Ex), ANCFmovingRigidbody.py (Ex), ANCFslidingJoint.py (Ex), ANCFslidingJoint2D.py (Ex), ANCFslidingJoint2Drigid.py (Ex), ANCFswitchingSlidingJoint2D.py (Ex), beltDriveALE.py (Ex), beltDriveReevingSystem.py (Ex), beltDrivesComparison.py (Ex), bicycleIftommBenchmark.py (Ex), camFollowerExample.py (Ex), ANCFcontactCircleTest.py (TM), ANCFcontactFrictionTest.py (TM), ANCFmovingRigidBodyTest.py (TM), …