generalContactCylinderTest.py

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  1#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2# This is an EXUDYN example
  3#
  4# Details:  model with GeneralContact of a cylinder modelled by spheres rolling on triangle ground mesh
  5#
  6# Author:   Johannes Gerstmayr
  7# Date:     2024-03-16
  8#
  9# Copyright:This file is part of Exudyn. Exudyn is free software. You can redistribute it and/or modify it under the terms of the Exudyn license. See 'LICENSE.txt' for more details.
 10#
 11#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 12
 13import exudyn as exu
 14from exudyn.utilities import *
 15import numpy as np
 16
 17useGraphics = True #without test
 18#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 19#you can erase the following lines and all exudynTestGlobals related operations if this is not intended to be used as TestModel:
 20try: #only if called from test suite
 21    from modelUnitTests import exudynTestGlobals #for globally storing test results
 22    useGraphics = exudynTestGlobals.useGraphics
 23except:
 24    class ExudynTestGlobals:
 25        pass
 26    exudynTestGlobals = ExudynTestGlobals()
 27#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 28
 29SC = exu.SystemContainer()
 30mbs = SC.AddSystem()
 31
 32#create an environment for mini example
 33
 34gravity = [0,0,-9.81]
 35
 36planeL = 4
 37p0 = [0.5*planeL,0,0]
 38
 39nPhi = 80  #spheres around circumference
 40nThick = 1 #spheres along cylinder axis (+1)
 41
 42rCyl = 0.25
 43tCyl = 0.1
 44rMarker = 0.02 #radius of spheres for contact points
 45
 46sRad = 0.02
 47k = 1e4
 48d = 0.0005*k
 49stepSize = 1e-3
 50
 51frictionCoeff = 0.2
 52ss = 10
 53
 54markerList = []
 55radiusList = []
 56gDataList = []
 57
 58
 59gContact = mbs.AddGeneralContact()
 60#gContact.verboseMode = 1
 61gContact.SetFrictionPairings(frictionCoeff*np.eye(1))
 62gContact.SetSearchTreeCellSize(numberOfCells=[ss,ss,ss])
 63# gContact.SetSearchTreeBox(pMin=np.array([-0.5*planeL,-0.5*planeL,-0.1]),
 64#                           pMax=np.array([0.5*planeL,0.5*planeL,0.1]))
 65#print('treesize=',ssx*ssx*ssy)
 66# gContact.sphereSphereContact = False
 67
 68#%% ground
 69gFloor = GraphicsDataCheckerBoard(p0,size=planeL, nTiles=10)
 70gDataList = [gFloor]
 71
 72
 73nGround = mbs.AddNode(NodePointGround(referenceCoordinates=[0,0,0] ))
 74mGround = mbs.AddMarker(MarkerNodeRigid(nodeNumber=nGround))
 75
 76[meshPoints, meshTrigs] = GraphicsData2PointsAndTrigs(gFloor)
 77#[meshPoints, meshTrigs] = RefineMesh(meshPoints, meshTrigs) #just to have more triangles on floor
 78gContact.AddTrianglesRigidBodyBased(rigidBodyMarkerIndex=mGround, contactStiffness=k, contactDamping=d, frictionMaterialIndex=0,
 79    pointList=meshPoints,  triangleList=meshTrigs)
 80
 81
 82#rigid body containing sphere markers:
 83inertia = InertiaCylinder(1000, tCyl, rCyl, 1)
 84# print(inertia)
 85
 86omegaY = 12
 87bCyl=mbs.CreateRigidBody(referencePosition=[0,0,rCyl*1.0],
 88                    initialVelocity=[omegaY*rCyl,0,0],
 89                    initialAngularVelocity=[0,omegaY*0.5,0],
 90                    initialRotationMatrix=RotationMatrixX(0.1),
 91                    inertia=inertia,
 92                    gravity = gravity,
 93                    nodeType = exu.NodeType.RotationRotationVector,
 94                    graphicsDataList=[GraphicsDataCylinder(pAxis=[0,-0.5*tCyl,0],vAxis=[0,tCyl,0], radius=rCyl,
 95                                                           color=[0.3,0.3,0.3,1],
 96                                                           alternatingColor=color4lightgrey,nTiles=64)]
 97                    )
 98nCyl = mbs.GetObject(bCyl)['nodeNumber']
 99#print(mbs.GetNode(nCyl))
100sPos = mbs.AddSensor(SensorBody(bodyNumber=bCyl, storeInternal=True,
101                                outputVariableType=exu.OutputVariableType.Position))
102sRot = mbs.AddSensor(SensorBody(bodyNumber=bCyl, storeInternal=True,
103                                outputVariableType=exu.OutputVariableType.Rotation))
104sVel = mbs.AddSensor(SensorBody(bodyNumber=bCyl, storeInternal=True,
105                                outputVariableType=exu.OutputVariableType.Velocity))
106sOmega = mbs.AddSensor(SensorBody(bodyNumber=bCyl, storeInternal=True,
107                                outputVariableType=exu.OutputVariableType.AngularVelocity))
108
109for phiI in range(nPhi):
110    phi = phiI/nPhi*2*pi
111    for j in range(nThick+1):
112        rCylMod = rCyl-rMarker
113        #compute local coordinates for markers
114        y = (j/nThick-0.5)*tCyl
115        x = rCylMod*sin(phi)
116        z = rCylMod*cos(phi)
117
118        m = mbs.AddMarker(MarkerBodyRigid(bodyNumber=bCyl, localPosition=[x,y,z]))
119        gContact.AddSphereWithMarker(m, radius=rMarker, contactStiffness=k, contactDamping=d, frictionMaterialIndex=0)
120
121
122
123#put ground here, such that it is transparent in background
124oGround=mbs.AddObject(ObjectGround(referencePosition= [0,0,0],
125                                    visualization=VObjectGround(graphicsData=gDataList)))
126
127
128mbs.Assemble()
129
130items=gContact.GetItemsInBox(pMin=[-4,-4,0], pMax=[4,4,20])
131#print('n spheres=',len(items['MarkerBasedSpheres']))
132
133
134tEnd = 2
135#tEnd = h*100
136simulationSettings = exu.SimulationSettings()
137simulationSettings.solutionSettings.writeSolutionToFile = False
138#simulationSettings.displayComputationTime = True
139#simulationSettings.displayStatistics = True
140simulationSettings.timeIntegration.verboseMode = 1
141# simulationSettings.parallel.numberOfThreads = 4
142# simulationSettings.timeIntegration.simulateInRealtime = True
143
144SC.visualizationSettings.general.graphicsUpdateInterval=0.02
145SC.visualizationSettings.general.drawCoordinateSystem=True
146SC.visualizationSettings.loads.show=False
147SC.visualizationSettings.bodies.show=True
148SC.visualizationSettings.markers.show=False
149
150SC.visualizationSettings.nodes.show=True
151SC.visualizationSettings.nodes.drawNodesAsPoint = False
152SC.visualizationSettings.nodes.defaultSize = 0 #must not be -1, otherwise uses autocomputed size
153SC.visualizationSettings.nodes.tiling = 4
154
155SC.visualizationSettings.window.renderWindowSize=[2000,1200]
156SC.visualizationSettings.openGL.multiSampling = 4
157#improved OpenGL rendering
158
159SC.visualizationSettings.contact.showSpheres = True
160
161SC.visualizationSettings.general.autoFitScene = False
162
163if useGraphics:
164    exu.StartRenderer()
165    if 'renderState' in exu.sys:
166        SC.SetRenderState(exu.sys['renderState'])
167    # mbs.WaitForUserToContinue()
168
169
170simulationSettings.timeIntegration.numberOfSteps = int(tEnd/stepSize)
171simulationSettings.timeIntegration.endTime = tEnd
172mbs.SolveDynamic(simulationSettings, solverType=exu.DynamicSolverType.ExplicitEuler)
173
174if useGraphics:
175    #SC.WaitForRenderEngineStopFlag()
176    exu.StopRenderer() #safely close rendering window!
177
178#%%+++++++++++++++++++
179q = mbs.GetSensorValues(sPos)
180q += mbs.GetSensorValues(sVel)
181q += mbs.GetSensorValues(sOmega)
182q += mbs.GetSensorValues(sRot)
183#print('q=', q)
184
185u = NormL2(q)
186exu.Print('solution of generalContactCylinderTest =',u)
187
188exudynTestGlobals.testError = u - (12.42377622187738 )
189exudynTestGlobals.testResult = u