Topology optimization of a simple cantilever beam

This example demonstrates the structural topology optimization of a simple cantilever beam. The structural analysis is performed with basic constraints and load, which is then transferred to the topology optimization.

Import necessary libraries

import os

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

Embed Mechanical and set global variables

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


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()


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

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.Front)
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

Import structural analsys

Download .mechdat file

structural_mechdat_file = download_file(
    "cantilever.mechdat", "pymechanical", "embedding"
)
app.open(structural_mechdat_file)
STRUCT = Model.Analyses[0]

STRUCT_SLN = STRUCT.Solution
STRUCT_SLN.Solve(True)

Display structural analsys results

Total deformation

STRUCT_SLN.Children[1].Activate()
Graphics.Camera.SetFit()
Graphics.ExportImage(
    os.path.join(cwd, "total_deformation.png"), image_export_format, settings_720p
)
display_image("total_deformation.png")

Equivalent stress

STRUCT_SLN.Children[2].Activate()
Graphics.Camera.SetFit()
Graphics.ExportImage(
    os.path.join(cwd, "equivalent_stress.png"), image_export_format, settings_720p
)
display_image("equivalent_stress.png")

Topology optimization

# Set MKS unit system

ExtAPI.Application.ActiveUnitSystem = MechanicalUnitSystem.StandardMKS

# Get structural analysis and link to topology optimization

TOPO_OPT = Model.AddTopologyOptimizationAnalysis()
TOPO_OPT.TransferDataFrom(STRUCT)

OPT_REG = DataModel.GetObjectsByType(DataModelObjectCategory.OptimizationRegion)[0]
OPT_REG.BoundaryCondition = BoundaryConditionType.AllLoadsAndSupports
OPT_REG.OptimizationType = OptimizationType.TopologyDensity


# Insert volume response constraint object for topology optimization
# Delete mass response constraint

MASS_CONSTRN = TOPO_OPT.Children[3]
MASS_CONSTRN.Delete()

# Add volume response constraint

VOL_CONSTRN = TOPO_OPT.AddVolumeConstraint()

# Insert member size manufacturing constraint

MEM_SIZE_MFG_CONSTRN = TOPO_OPT.AddMemberSizeManufacturingConstraint()
MEM_SIZE_MFG_CONSTRN.Minimum = ManuMemberSizeControlledType.Manual
MEM_SIZE_MFG_CONSTRN.MinSize = Quantity("2.4 [m]")


TOPO_OPT.Activate()
Graphics.Camera.SetFit()
Graphics.ExportImage(
    os.path.join(cwd, "boundary_conditions.png"), image_export_format, settings_720p
)
display_image("boundary_conditions.png")

Solve

TOPO_OPT_SLN = TOPO_OPT.Solution
TOPO_OPT_SLN.Solve(True)

Messages

Messages = ExtAPI.Application.Messages
if Messages:
    for message in Messages:
        print(f"[{message.Severity}] {message.DisplayString}")
else:
    print("No [Info]/[Warning]/[Error] Messages")

[Info] For geometric constraint (Mass, Volume, Center of Gravity or Moment of Inertia constraints), it is recommended to use Criterion of the upstream Measure folder (inserted from Model object).
[Warning] The default mesh size calculations have changed in 18.2. Specifically, the default min size values and/or defeature size values scale dynamically in relation to the element (max face) size. These settings could lead to a significantly different mesh, so the model will be resumed using the previous values for min size and defeature size rather than leaving those values as default.

Display results

TOPO_OPT_SLN.Children[1].Activate()
TOPO_DENS = TOPO_OPT_SLN.Children[1]

Add smoothing to the STL

TOPO_DENS.AddSmoothing()
TOPO_OPT.Solution.EvaluateAllResults()
TOPO_DENS.Children[0].Activate()
Graphics.Camera.SetFit()
Graphics.ExportImage(
    os.path.join(cwd, "topo_opitimized_smooth.png"), image_export_format, settings_720p
)
display_image("topo_opitimized_smooth.png")

Export animation

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

TOPO_DENS.ExportAnimation(
    os.path.join(cwd, "Topo_opitimized.gif"), animation_export_format, settings_720p
)

Review the results

# Print topology density results
print("Topology Density Results")
print("Minimum Density: ", TOPO_DENS.Minimum)
print("Maximum Density: ", TOPO_DENS.Maximum)
print("Iteration Number: ", TOPO_DENS.IterationNumber)
print("Original Volume: ", TOPO_DENS.OriginalVolume.Value)
print("Final Volume: ", TOPO_DENS.FinalVolume.Value)
print("Percent Volume of Original: ", TOPO_DENS.PercentVolumeOfOriginal)
print("Original Mass: ", TOPO_DENS.OriginalMass.Value)
print("Final Mass: ", TOPO_DENS.FinalMass.Value)
print("Percent Mass of Original: ", TOPO_DENS.PercentMassOfOriginal)

Topology Density Results
Minimum Density:  0.0010000000474974513
Maximum Density:  1.0
Iteration Number:  35
Original Volume:  1000.0000054389238
Final Volume:  522.4924773573875
Percent Volume of Original:  52.24924745155908
Original Mass:  7849999.975463867
Final Mass:  4101565.9057617188
Percent Mass of Original:  52.24924737046705

Project tree

app.print_tree()

├── Project
|  ├── Model
|  |  ├── Geometry Imports
|  |  |  ├── Geometry Import
|  |  ├── Geometry
|  |  |  ├── Surface Body Bodies
|  |  |  |  ├── Surface Body
|  |  ├── Materials
|  |  |  ├── Structural Steel
|  |  ├── Coordinate Systems
|  |  |  ├── Global Coordinate System
|  |  |  ├── Coordinate System
|  |  |  ├── Coordinate System 2
|  |  |  ├── Coordinate System 3
|  |  |  ├── Coordinate System 4
|  |  |  ├── Coordinate System 5
|  |  |  ├── Coordinate System 6
|  |  |  ├── Coordinate System 7
|  |  |  ├── Coordinate System 8
|  |  ├── Remote Points
|  |  ├── Mesh
|  |  |  ├── Face Sizing
|  |  ├── Named Selections
|  |  |  ├── Selection
|  |  |  ├── Bottom_Elements
|  |  |  ├── Top_Elements
|  |  |  ├── Middle1_Elements
|  |  |  ├── Middle2_Elements
|  |  |  ├── Left1_Elements
|  |  |  ├── Left2_Elements
|  |  |  ├── Right1_Elements
|  |  |  ├── Right2_Elements
|  |  |  ├── Optimized_Shape
|  |  |  ├── Outside_Optimized_Shape
|  |  |  ├── Selection 2
|  |  |  ├── Selection 3
|  |  |  ├── Selection 4
|  |  |  ├── Selection 5
|  |  ├── Static Structural
|  |  |  ├── Analysis Settings
|  |  |  ├── Fixed Support
|  |  |  ├── Nodal Force
|  |  |  ├── Solution
|  |  |  |  ├── Solution Information
|  |  |  |  ├── Total Deformation
|  |  |  |  ├── Equivalent Stress
|  |  ├── Structural Optimization
|  |  |  ├── Analysis Settings
|  |  |  ├── Optimization Region
|  |  |  ├── Objective
|  |  |  ├── Response Constraint
|  |  |  ├── Manufacturing Constraint
|  |  |  ├── Solution
|  |  |  |  ├── Solution Information
|  |  |  |  |  ├── Topology Density Tracker
|  |  |  |  ├── Topology Density
|  |  |  |  |  ├── Smoothing

Cleanup

Save project

app.save(os.path.join(cwd, "cantilever_beam_topology_optimization.mechdat"))
app.new()

Delete the example files

delete_downloads()

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