Note

Go to the end to download the full example code.

Nonlinear Analysis of a Rubber Boot Seal Model#

This example demonstrates a nonlinear 3D analysis of a rubber boot seal to:

Create a rigid-flexible contact pair between a rigid shaft and a rubber boot part.
Specify ramped effects using the On Gauss Point Detection Method to update contact stiffness at each iteration.
Specify contact pairs at the inner and outer surfaces of the rubber boot.
Specify non-ramped effects using the Nodal-Projected Normal From Contact Detection Method to update contact stiffness at each iteration.

Import necessary libraries#

import os

from PIL import Image
from ansys.mechanical.core import App
from ansys.mechanical.core.examples import delete_downloads, download_file
from matplotlib import image as mpimg
from matplotlib import pyplot as plt
from matplotlib.animation import FuncAnimation

Embed mechanical and set global variables

app = App()
app.update_globals(globals())
print(app)

cwd = os.path.join(os.getcwd(), "out")


def display_image(image_name):
    plt.figure(figsize=(16, 9))
    plt.imshow(mpimg.imread(os.path.join(cwd, image_name)))
    plt.xticks([])
    plt.yticks([])
    plt.axis("off")
    plt.show()

Ansys Mechanical [Ansys Mechanical Enterprise]
Product Version:242
Software build date: 06/03/2024 09:35:09

Configure graphics for image export#

Graphics.Camera.SetSpecificViewOrientation(ViewOrientationType.Iso)
Graphics.Camera.SetFit()
image_export_format = GraphicsImageExportFormat.PNG
settings_720p = Ansys.Mechanical.Graphics.GraphicsImageExportSettings()
settings_720p.Resolution = GraphicsResolutionType.EnhancedResolution
settings_720p.Background = GraphicsBackgroundType.White
settings_720p.Width = 1280
settings_720p.Height = 720
settings_720p.CurrentGraphicsDisplay = False

Download geometry and materials files#

geometry_path = download_file(
    "example_05_td26_Rubber_Boot_Seal.agdb", "pymechanical", "00_basic"
)
mat_path = download_file("example_05_Boot_Mat.xml", "pymechanical", "00_basic")

Import geometry and material#

Import material

materials = Model.Materials
materials.Import(mat_path)
print("Material import done !")

Material import done !

Import geometry

geometry_import = Model.GeometryImportGroup.AddGeometryImport()
geometry_import_format = (
    Ansys.Mechanical.DataModel.Enums.GeometryImportPreference.Format.Automatic
)
geometry_import_preferences = Ansys.ACT.Mechanical.Utilities.GeometryImportPreferences()
geometry_import_preferences.ProcessNamedSelections = True
geometry_import_preferences.ProcessCoordinateSystems = True
geometry_import.Import(
    geometry_path, geometry_import_format, geometry_import_preferences
)

app.plot()

Static Scene

Interactive Scene

Setup the Analysis#

Set up the unit system

ExtAPI.Application.ActiveUnitSystem = MechanicalUnitSystem.StandardNMM
ExtAPI.Application.ActiveAngleUnit = AngleUnitType.Radian

Store all main tree nodes as variables

GEOM = Model.Geometry
PRT1 = [x for x in Tree.AllObjects if x.Name == "Part"][0]
PRT2 = [x for x in Tree.AllObjects if x.Name == "Solid"][1]
CS_GRP = Model.CoordinateSystems
GCS = CS_GRP.Children[0]

Add static structural analysis

Model.AddStaticStructuralAnalysis()
STAT_STRUC = Model.Analyses[0]
ANA_SETTING = STAT_STRUC.Children[0]
STAT_STRUC_SOLN = STAT_STRUC.Solution
SOLN_INFO = STAT_STRUC_SOLN.SolutionInformation

Define named selection and coordinate system

NS_GRP = ExtAPI.DataModel.Project.Model.NamedSelections
TOP_FACE = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Top_Face"
][0]
BOTTOM_FACE = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Bottom_Face"
][0]
SYMM_FACES30 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Symm_Faces30"
][0]
FACES2 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Faces2"
][0]
CYL_FACES2 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Cyl_Faces2"
][0]
RUBBER_BODIES30 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Rubber_Bodies30"
][0]
INNER_FACES30 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Inner_Faces30"
][0]
OUTER_FACES30 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Outer_Faces30"
][0]
SHAFT_FACE = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Shaft_Face"
][0]
SYMM_FACES15 = [
    i
    for i in NS_GRP.GetChildren[Ansys.ACT.Automation.Mechanical.NamedSelection](True)
    if i.Name == "Symm_Faces15"
][0]

LCS1 = CS_GRP.AddCoordinateSystem()
LCS1.OriginY = Quantity("97[mm]")

Assign material

PRT1.Material = "Boot"
PRT2.StiffnessBehavior = StiffnessBehavior.Rigid

Define connections

CONN_GRP = Model.Connections
CONT_REG1 = CONN_GRP.AddContactRegion()
CONT_REG1.TargetLocation = SHAFT_FACE
CONT_REG1.SourceLocation = INNER_FACES30
CONT_REG1.ContactType = ContactType.Frictional
CONT_REG1.FrictionCoefficient = 0.2
CONT_REG1.Behavior = ContactBehavior.Asymmetric
CONT_REG1.SmallSliding = ContactSmallSlidingType.Off
CONT_REG1.DetectionMethod = ContactDetectionPoint.OnGaussPoint
CONT_REG1.UpdateStiffness = UpdateContactStiffness.EachIteration
CONT_REG1.InterfaceTreatment = ContactInitialEffect.AddOffsetRampedEffects
CONT_REG1.TargetGeometryCorrection = TargetCorrection.Smoothing
CONT_REG1.TargetOrientation = TargetOrientation.Cylinder
CONT_REG1.TargetStartingPoint = GCS
CONT_REG1.TargetEndingPoint = LCS1

CONTS = CONN_GRP.Children[0]
CONT_REG2 = CONTS.AddContactRegion()
CONT_REG2.SourceLocation = INNER_FACES30
CONT_REG2.TargetLocation = INNER_FACES30
CONT_REG2.ContactType = ContactType.Frictional
CONT_REG2.FrictionCoefficient = 0.2
CONT_REG2.Behavior = ContactBehavior.Asymmetric
CONT_REG2.SmallSliding = ContactSmallSlidingType.Off
CONT_REG2.DetectionMethod = ContactDetectionPoint.NodalProjectedNormalFromContact
CONT_REG2.UpdateStiffness = UpdateContactStiffness.EachIteration
CONT_REG2.NormalStiffnessValueType = ElementControlsNormalStiffnessType.Factor
CONT_REG2.NormalStiffnessFactor = 1

CONT_REG3 = CONTS.AddContactRegion()
CONT_REG3.SourceLocation = OUTER_FACES30
CONT_REG3.TargetLocation = OUTER_FACES30
CONT_REG3.ContactType = ContactType.Frictional
CONT_REG3.FrictionCoefficient = 0.2
CONT_REG3.Behavior = ContactBehavior.Asymmetric
CONT_REG3.SmallSliding = ContactSmallSlidingType.Off
CONT_REG3.DetectionMethod = ContactDetectionPoint.NodalProjectedNormalFromContact
CONT_REG3.UpdateStiffness = UpdateContactStiffness.EachIteration
CONT_REG3.NormalStiffnessValueType = ElementControlsNormalStiffnessType.Factor
CONT_REG3.NormalStiffnessFactor = 1

Mesh#

MSH = Model.Mesh
FACE_MSH = MSH.AddFaceMeshing()
FACE_MSH.Location = SHAFT_FACE
FACE_MSH.InternalNumberOfDivisions = 1

MSH_SIZE = MSH.AddSizing()
MSH_SIZE.Location = SYMM_FACES15
MSH_SIZE.ElementSize = Quantity("2 [mm]")

MSH.ElementOrder = ElementOrder.Linear
MSH.Resolution = 2

MSH.GenerateMesh()

Graphics.ExportImage(os.path.join(cwd, "mesh.png"), image_export_format, settings_720p)
display_image("mesh.png")

Define remote points#

scope them to the top and bottom faces of rigid shaft

RMPT01 = Model.AddRemotePoint()
RMPT01.Location = BOTTOM_FACE
RMPT01.Behavior = LoadBehavior.Rigid

RMPT02 = Model.AddRemotePoint()
RMPT02.Location = TOP_FACE
RMPT02.Behavior = LoadBehavior.Rigid

Analysis settings#

ANA_SETTING.Activate()
ANA_SETTING.LargeDeflection = True
ANA_SETTING.Stabilization = StabilizationType.Off

ANA_SETTING.NumberOfSteps = 2
ANA_SETTING.CurrentStepNumber = 1
ANA_SETTING.AutomaticTimeStepping = AutomaticTimeStepping.On
ANA_SETTING.DefineBy = TimeStepDefineByType.Substeps
ANA_SETTING.InitialSubsteps = 5
ANA_SETTING.MinimumSubsteps = 5
ANA_SETTING.MaximumSubsteps = 1000
ANA_SETTING.StoreResultsAt = TimePointsOptions.EquallySpacedPoints
ANA_SETTING.StoreResulsAtValue = 5

ANA_SETTING.CurrentStepNumber = 2
ANA_SETTING.AutomaticTimeStepping = AutomaticTimeStepping.On
ANA_SETTING.DefineBy = TimeStepDefineByType.Substeps
ANA_SETTING.InitialSubsteps = 10
ANA_SETTING.MinimumSubsteps = 10
ANA_SETTING.MaximumSubsteps = 1000
ANA_SETTING.StoreResultsAt = TimePointsOptions.EquallySpacedPoints
ANA_SETTING.StoreResulsAtValue = 10

ANA_SETTING.CurrentStepNumber = 3
ANA_SETTING.AutomaticTimeStepping = AutomaticTimeStepping.On
ANA_SETTING.DefineBy = TimeStepDefineByType.Substeps
ANA_SETTING.InitialSubsteps = 30
ANA_SETTING.MinimumSubsteps = 30
ANA_SETTING.MaximumSubsteps = 1000
ANA_SETTING.StoreResultsAt = TimePointsOptions.EquallySpacedPoints
ANA_SETTING.StoreResulsAtValue = 20

SOLN_INFO.NewtonRaphsonResiduals = 4

Loads and boundary conditions#

REM_DISP = STAT_STRUC.AddRemoteDisplacement()
REM_DISP.Location = RMPT01
REM_DISP.XComponent.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.XComponent.Output.DiscreteValues = [
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
]
REM_DISP.YComponent.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.YComponent.Output.DiscreteValues = [
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
    Quantity("-10 [mm]"),
    Quantity("-10 [mm]"),
]
REM_DISP.ZComponent.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.ZComponent.Output.DiscreteValues = [
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
    Quantity("0 [mm]"),
]

REM_DISP.RotationX.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.RotationX.Output.DiscreteValues = [
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
]
REM_DISP.RotationY.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.RotationY.Output.DiscreteValues = [
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
]
REM_DISP.RotationZ.Inputs[0].DiscreteValues = [
    Quantity("0 [s]"),
    Quantity("1 [s]"),
    Quantity("2 [s]"),
    Quantity("3 [s]"),
]
REM_DISP.RotationZ.Output.DiscreteValues = [
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0 [rad]"),
    Quantity("0.55 [rad]"),
]

FRIC_SUP01 = STAT_STRUC.AddFrictionlessSupport()
FRIC_SUP01.Location = SYMM_FACES30
FRIC_SUP01.Name = "Symmetry_BC"
FRIC_SUP02 = STAT_STRUC.AddFrictionlessSupport()
FRIC_SUP02.Location = FACES2
FRIC_SUP02.Name = "Boot_Bottom_BC"
FRIC_SUP03 = STAT_STRUC.AddFrictionlessSupport()
FRIC_SUP03.Location = CYL_FACES2
FRIC_SUP03.Name = "Boot_Radial_BC"

Add results#

TOT_DEF = STAT_STRUC.Solution.AddTotalDeformation()
TOT_DEF.Location = RUBBER_BODIES30

EQV_STRS = STAT_STRUC.Solution.AddEquivalentStress()
EQV_STRS.Location = RUBBER_BODIES30

Solve#

STAT_STRUC.Solution.Solve(True)

Postprocessing#

Total deformation

Tree.Activate([TOT_DEF])
Graphics.ExportImage(
    os.path.join(cwd, "totaldeformation.png"), image_export_format, settings_720p
)
display_image("totaldeformation.png")

Equivalent stress

Tree.Activate([EQV_STRS])
Graphics.ExportImage(
    os.path.join(cwd, "equivalent_stress.png"), image_export_format, settings_720p
)
display_image("equivalent_stress.png")

Total deformation animation

animation_export_format = (
    Ansys.Mechanical.DataModel.Enums.GraphicsAnimationExportFormat.GIF
)
settings_720p = Ansys.Mechanical.Graphics.AnimationExportSettings()
settings_720p.Width = 1280
settings_720p.Height = 720

TOT_DEF.ExportAnimation(
    os.path.join(cwd, "totaldeformation.gif"), animation_export_format, settings_720p
)
gif = Image.open(os.path.join(cwd, "totaldeformation.gif"))
fig, ax = plt.subplots(figsize=(16, 9))
ax.axis("off")
img = ax.imshow(gif.convert("RGBA"))


def update(frame):
    gif.seek(frame)
    img.set_array(gif.convert("RGBA"))
    return [img]


ani = FuncAnimation(
    fig, update, frames=range(gif.n_frames), interval=200, repeat=True, blit=True
)
plt.show()

Cleanup#

Save project

app.save(os.path.join(cwd, "non-linear-rubber-boot-seal.mechdat"))
app.new()

# delete example file
delete_downloads()

True

Total running time of the script: (1 minutes 47.625 seconds)

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