Bug located in ... meshing a part with two volumes using multizone control and different element size for both volumes

[luca3479]

Hi, I was wonder if is possible to obtain a pure hexahedral mesh of a single part (two rectangles connected) with two zone_expression "solid" (first rectangle) and "solid1" (second rectangle) using multi zone meshing method and different element size for the two volumes, coarse hexahedral mesh for "solid" and fine hexahedral mesh for "solid1". I would use prime version 0.8.0 and Ansys 251.
Thank you in advance.

[waltersma]

Hi @luca3479,

Please can you be more descriptive about what your expectations are for the resulting mesh and what you are targeting for the cell size change between the two bodies if they are connected. Maybe you can draw a diagram of what you would like to achieve with the transition between zones. As of now the options for growing hexahedral meshes between two adjacent connected zones would be rather limited. But if you add more detail we may have a better idea of your expectations.

Thanks

[luca3479]

Hi @waltersma,
Thank you very much for your reply.
This is the part that I created in Inventor as a two separated rectangles:

Then I opened it in discovery and did the share topology to connect the two rectangles for meshing.
Once in ansys meshing I achieved this type of mesh using MultiZone meshing method and did some edge sizing to obtain the let's say "coarse" and "fine" mesh.. this is only to give you an idea, the fine and coarse mesh depends then on the application case and the mesh sensitivity analysis.

So I want obtain the same pure hexahedral mesh using ansys prime mesh and MultiZone control to understand also how prime works with sizing and then apply the procedure to real more complex cases of study by an automatized approach that I consider very useful if are requested parametric analysis of multiple cases.

[luca3479]

Dear @waltersma,

Do you have any suggestion to do this example of meshing about multizone meshing with bodies with different sizing throughout the length of the edge?
Let me know if you have any solution.

Best regards,
Luca

[waltersma]

Hi @luca3479 ,

The exposure of multizone in beta is currently quite limited in comparison to that in ansys meshing. As such, some of the controls can only be passed as singular operations with the current exposed apis. However for the example you showed it is possible to use them to obtain the result. Extrapolating these to more generalised cases will be much harder for now.

Two named selections were also added to this model, "named_edges" on the long edges of one of the blocks, and "source_target" for faces either side of the adjacent block to help with the controls needed.

import ansys.meshing.prime as prime
from ansys.meshing.prime.graphics.plotter import PrimePlotter

prime_client = prime.launch_prime()
model = prime_client.model

file_io = prime.FileIO(model=model)

# Import the geometry file
file_io.import_cad(
    r"blocks.pmdb",
    prime.ImportCadParams(model=model, cad_reader_route=prime.CadReaderRoute.WORKBENCH),
)
print(model)

# Get the part
part = model.parts[0]

# Create multizone control
multizone_control = model.control_data.create_multi_zone_control()

# Set volume scope for multizone
volume_scope = prime.ScopeDefinition(
    model=model,
    entity_type=prime.ScopeEntity.VOLUME,
    evaluation_type=prime.ScopeEvaluationType.ZONES,
    zone_expression="*",
)
multizone_control.set_volume_scope(volume_scope)

# Set surface scope for multizone
surface_scope = prime.ScopeDefinition(
    model=model,
    entity_type=prime.ScopeEntity.FACEZONELETS,
    evaluation_type=prime.ScopeEvaluationType.LABELS,
    label_expression="*",
)
multizone_control.set_surface_scope(surface_scope)

# Set global sizing parameters for multizone
sizing_params = prime.MultiZoneSizingParams(model)
sizing_params.max_size = 1.0
sizing_params.min_size = 1.0
multizone_control.set_multi_zone_sizing_params(sizing_params)

# Set sweep control for sizing in direction-1
multizone_control.set_sweep_mesh_params(
    prime.MultiZoneSweepMeshParams(
        model,
        sweep_type=prime.SweepType.STANDARD,
        sweep_mesh_size=0.4,
        source_and_target_scope=prime.ScopeDefinition(
            model=model,
            entity_type=prime.ScopeEntity.FACEZONELETS,
            label_expression="source_target",
        ),
    )
)

# Set edge biasing for sizing in direction-2
multizone_control.set_edge_biasing_params(
    prime.MultiZoneEdgeBiasingParams(
        model,
        edge_scope=prime.ScopeDefinition(
            model=model,
            entity_type=prime.ScopeEntity.EDGEZONELETS,
            label_expression="named_edges",
        ),
        face_scope=prime.ScopeDefinition(
            model=model,
            entity_type=prime.ScopeEntity.FACEZONELETS,
            label_expression="*",
        ),
        n_divisions=8,
        bias_factor=1.0,
    )
)

# Set mapping control for multizone
multizone_control.set_map_mesh_params(
    prime.MultiZoneMapMeshParams(
        model,
        scope=prime.ScopeDefinition(
            model=model,
            entity_type=prime.ScopeEntity.FACEZONELETS,
            evaluation_type=prime.ScopeEvaluationType.ZONES,
            zone_expression="*",
        ),
    )
)

# Mesh with multizone control
autoMeshParams = prime.AutoMeshParams(model)
autoMeshParams.multi_zone_control_ids = [multizone_control.id]
autoMesher = prime.AutoMesh(model)
result = autoMesher.mesh(part.id, autoMeshParams)

# Display result
display = PrimePlotter()
display.plot(model)
display.show()

"source_target" and "named_edges" named selections:

Resulting mesh:

[luca3479]

Dear @waltersma,

Thank you for your answer and code, this was exactly what I was trying to do.

Best regards,
Luca