def testHangingCableANCF(self):
g = np.array([0., 0., -9.81])
system = fsi.ProtChSystem()
system.ChSystem.Set_G_acc(chrono.ChVectorD(g[0], g[1], g[2]))
system.setTimeStep(1e-1)
# timestepper = chrono.ChTimestepperEulerImplicitLinearized()
# system.ChSystem.SetTimestepper(timestepper)
solver = chrono.ChSolverMINRES()
system.ChSystem.SetSolver(solver)
solver.SetMaxIterations(100)
solver.EnableWarmStart(True)
solver.EnableDiagonalPreconditioner(True)
solver.SetVerbose(True)
system.ChSystem.SetSolverForceTolerance(1e-10)
system.ChSystem.SetSolverMaxIterations(100)
mesh = fsi.ProtChMesh(system)
L = np.array([5.])
nb_elems = np.array([3])
d = np.array([1e-3])
rho = np.array([1000.])
E = np.array([1e10])
cable_type = b"CableANCF"
fairlead_body = fsi.ProtChBody(system)
fairlead_body.ChBody.SetBodyFixed(True)
mooring = fsi.ProtChMoorings(system=system,
mesh=mesh,
length=L,
nb_elems=nb_elems,
d=d,
rho=rho,
E=E,
beam_type=cable_type)
mooring.external_forces_manual = True # tri: should work without this line
# vertical cable
mooring.setNodesPositionFunction(lambda s: np.array([0., 0., s]),
lambda s: np.array([0., 0., 1.]))
mooring.setNodesPosition()
mooring.buildNodes()
mooring.attachBackNodeToBody(fairlead_body)
system.calculate_init()
system.calculate(0.5)
T = mooring.getTensionBack()
strain = mooring.getNodesTension(eta=1.)[-1] * np.pi * d**2 / 4 * E
T_sol = -np.ones(3) * g * rho * (np.pi * d**2 / 4. * L)
npt.assert_almost_equal(-T, T_sol)
# Chrono # SYSTEM # create system system = fsi.ProtChSystem() # access chrono object chsystem = system.getChronoObject() # communicate gravity to system # can also be set with: # system.ChSystem.Set_G_acc(pychrono.ChVectorD(g[0], g[1], g[2])) system.setGravitationalAcceleration(g) # set maximum time step for system system.setTimeStep(1e-4) solver = pychrono.ChSolverMINRES() chsystem.SetSolver(solver) # BODY # create floating body body = fsi.ProtChBody(system=system) # give it a name body.setName(b'my_body') # attach shape: this automatically adds a body at the barycenter of the caisson shape body.attachShape(caisson) # set 2D width (for force calculation) body.setWidth2D(0.29) # access chrono object chbody = body.getChronoObject() # impose constraints
def __init__(self,
configuration,
visualization: bool = False,
output: Optional = None) -> None:
# TODO a copy of the configuration is better
self._conf = configuration
self._visualization = visualization
self._output = output
self._app = None
# TODO not sure about the meaning of theese two parameters, take them from the configuation
chrono.ChCollisionInfo.SetDefaultEffectiveCurvatureRadius(1)
chrono.ChCollisionModel.SetDefaultSuggestedMargin(0.006)
# TODO look into the parameters of the system
# e.g. MinBounceSpeed, Gravity
self._system = chrono.ChSystemSMC()
if self._visualization:
# TODO take the data path, the title, the dimension and do_[something] from the configuration
chrono.SetChronoDataPath(
"/home/gianluca/anaconda3/envs/chrono/share/chrono/data/")
self._app = irr.ChIrrApp(
self._system,
"Artificial Skin",
irr.dimension2du(1024, 768),
do_fullscreen=False,
do_shadows=True,
do_antialias=True,
)
self._app.AddTypicalSky()
self._app.AddTypicalLights()
# TODO take the info for the came and lighs from the configuation
self._app.AddTypicalCamera(irr.vector3df(-1, -1, 0),
irr.vector3df(0, 0, 0))
# TODO this has too many parameters and it is not that important
self._app.AddLightWithShadow(
irr.vector3df(1.5, 5.5, -2.5),
irr.vector3df(0, 0, 0),
3,
2.2,
7.2,
40,
512,
irr.SColorf(1, 1, 1),
)
self._app.AddShadowAll()
self._app.SetTimestep(0.004)
self._make_sheets()
self._make_sensors()
# TODO make the load class -> it takes a node / pair of indexes and time and return the force
self._add_forces()
# TODO look at all the parameters of the solver and the stepper
# TODO consider also mkl.ChSolverMKL
# TODO take the parameters from the configuration
self._solver = chrono.ChSolverMINRES()
self._system.SetSolver(self._solver)
self._solver.SetMaxIterations(1000)
self._solver.SetTolerance(1e-12)
self._solver.EnableDiagonalPreconditioner(True)
self._solver.SetVerbose(
False) # don't take this from the configuration
# HHT implicit integrator for II order systems, adaptive
# TODO take the parameters from the configuaration
self._stepper = chrono.ChTimestepperHHT(self._system)
self._system.SetTimestepper(self._stepper)
self._stepper.SetAlpha(-0.2)
self._stepper.SetMaxiters(100)
self._stepper.SetAbsTolerances(1e-5)
self._stepper.SetMode(chrono.ChTimestepperHHT.POSITION)
self._stepper.SetScaling(True)
# TODO from configuarion
# length of the simulation
self._life = 5 # seconds
my_mesh.AddAsset(mvisualizemeshC) mvisualizemeshD = fea.ChVisualizationFEAmesh(my_mesh) mvisualizemeshD.SetFEMglyphType(fea.ChVisualizationFEAmesh.E_GLYPH_NONE) mvisualizemeshD.SetFEMdataType(fea.ChVisualizationFEAmesh.E_PLOT_SURFACE) mvisualizemeshD.SetSymbolsScale(1) mvisualizemeshD.SetColorscaleMinMax(-0.5, 5) mvisualizemeshD.SetZbufferHide(False) my_mesh.AddAsset(mvisualizemeshD) application.AssetBindAll() application.AssetUpdateAll() # Perform a dynamic time integration: solver = chrono.ChSolverMINRES() my_system.SetSolver(solver) solver.SetMaxIterations(1000) solver.SetTolerance(1e-10) solver.EnableDiagonalPreconditioner(True) solver.SetVerbose(False) mystepper = chrono.ChTimestepperHHT(my_system) my_system.SetTimestepper(mystepper) mystepper.SetAlpha(-0.2) mystepper.SetMaxiters(100) mystepper.SetAbsTolerances(1e-5) mystepper.SetMode(chrono.ChTimestepperHHT.POSITION) mystepper.SetScaling(True) application.SetTimestep(0.004)
