- Geometry In H Geomet r y In H Geomet r y In H Geomet r y In H Geomet r y In H This chapter has been reviewed and has additional mat e This chapter has been reviewed and has additional mat e Matthias Goelke. Matthias Goelke. HyperMesh Geometr y T erminology HyperMesh Geometr y T erminology hile dealing with geometry it is important t o be familiar w hile dealing with geometry it is important t o be familiar w y our CAE project typically starts with the import of given y our CAE project typically starts with the import of given STEP , UG, IGES, SolidWorks, solidThinking etc. (of course STEP , UG, IGES, SolidWorks, solidThinking etc. (of course While the importation of data generally occurs with little error , the While the importation of data generally occurs with little error , the wide variety of t ools t o remedy these geometric issues (this is one wide variety of t ools t o remedy these geometric issues (this is one Some of the issues described below do exist because when des Some of the issues described below do exist because when des those of analysts trying t o use the data. For a designer , a single sm those of analysts trying t o use the data. For a designer , a single sm Some resulting geometry issues: Some resulting geometry issues: • Surfaces are not stitched t ogether (i.e. there is a gap b • Surfaces are not stitched t ogether (i.e. there is a gap b • Very small surfaces are squeezed between regular sur • Very small surfaces are squeezed between regular sur • The juncture between two surfaces oft en contains gap 1 1 HyperMesh - HyperMesh HyperMesh HyperMesh HyperMesh erial included by Rahul Ponginan, Prakash Pagadala and erial included by Rahul Ponginan, Prakash Pagadala and with the relevant HyperMesh t erminology: with the relevant HyperMesh t erminology: CAD data e.g. Catia, CAD data e.g. Catia, e, y ou ma y create y our CAD model in HyperMesh as well). e, y ou ma y create y our CAD model in HyperMesh as well). here are issues that can occur , and as such, HyperMesh off ers a here are issues that can occur , and as such, HyperMesh off ers a of the many reasons why HyperMesh is used in so many places). of the many reasons why HyperMesh is used in so many places). signers create CAD geometry , their priorities are diff erent from signers create CAD geometry , their priorities are diff erent from mooth surface is typically split into smaller patches. mooth surface is typically split into smaller patches. between surfaces) between surfaces) rfaces rfaces ps, overlaps, or other misalignments
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-Geome try In HyperMesh GeometryIn HyperMeshaltairuniversity.com/wp-content/uploads/2014/02/Geometry.pdfsu rfaces.Shared edges are colored green by de fault. you typically want tohave),
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- Geometry In HyperMesh - Geometry In HyperMesh
Geometry In HyperMeshGeometry In HyperMeshGeometry In HyperMeshGeometry In HyperMesh
This chapter has been reviewed and has additional material This chapter has been reviewed and has additional material
Below is a general strategy that can be followed to perform the topologyBelow is a general strategy that can be followed to perform the topology
be changed to suit the needs of your model, but it provides a good be changed to suit the needs of your model, but it provides a good
1. Understand the size and scale of the model1. Understand the size and scale of the model
• With models that represent everything from full size ships• With models that represent everything from full size ships
on a computer monitor, it is often difficult to understandon a computer monitor, it is often difficult to understand
overall size of the model and determine a global elementoverall size of the model and determine a global element
2. Set a cleanup tolerance based upon the previously determined global element size.2. Set a cleanup tolerance based upon the previously determined global element size.
• With the element size established, a cleanup tolerance• With the element size established, a cleanup tolerance
size to be closed by the topology functions. This valuesize to be closed by the topology functions. This value
beyond this limit can introduce distortion into the meshbeyond this limit can introduce distortion into the mesh
3. Use topology display tools to determine what needs to be fixed.3. Use topology display tools to determine what needs to be fixed.
selector to By 2D Toposelector to By 2D Topo
• Visualization mode: By Comp (which assigns the color • Visualization mode: By Comp (which assigns the color
• Visualization mode: By 2D Topo• Visualization mode: By 2D Topo
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HyperMesh -HyperMesh -
what is called Geometry Cleanup.what is called Geometry Cleanup.
opology repair. This is a generalized strategy which may need toopology repair. This is a generalized strategy which may need to
a good starting point to perform the topology repair.a good starting point to perform the topology repair.
ships to microscopic electronic parts all residing in a graphics areaships to microscopic electronic parts all residing in a graphics area
understand the overall scope of the model. It is critical to get an idea of theunderstand the overall scope of the model. It is critical to get an idea of the
element size that will be applied to the eventual mesh.element size that will be applied to the eventual mesh.
ermined global element size.ermined global element size.
olerance can now be set. The cleanup tolerance specifies the largest gapolerance can now be set. The cleanup tolerance specifies the largest gap
value should never exceed 15-20% of the global element size. Valuesvalue should never exceed 15-20% of the global element size. Values
mesh.mesh.
ed. For instance, to display the topology of 2D geometry set theed. For instance, to display the topology of 2D geometry set the
the color of the component)the color of the component)
- Geometry In HyperMesh - Geometry In HyperMesh
• Visualization mode: Mixed which assigns the component color and adds • Visualization mode: Mixed which assigns the component color and adds
4. Find duplicate surfaces and delete them.4. Find duplicate surfaces and delete them.
• To delete duplicate surfaces, from the menu bar select • To delete duplicate surfaces, from the menu bar select
5. Use equivalence to combine as many free edge pairs as possible.5. Use equivalence to combine as many free edge pairs as possible.
• Visually verify no surfaces were collapsed with this function.• Visually verify no surfaces were collapsed with this function.
6. Use toggle to combine any remaining edges.6. Use toggle to combine any remaining edges.
• Use replace if more control is needed.• Use replace if more control is needed.
7. Use filler surface to fill in any missing surfaces.7. Use filler surface to fill in any missing surfaces.
8. The equivalence, toggle, and filler surface can be accessed within 8. The equivalence, toggle, and filler surface can be accessed within
• To access the Quick Edit panel, from the menu bar select • To access the Quick Edit panel, from the menu bar select
Topology Repair: Tools And PanelsTopology Repair: Tools And Panels
The perimeter of a surface is defined by edges. There are four types The perimeter of a surface is defined by edges. There are four types
• Free edges• Free edges
• Shared edges• Shared edges
• Suppressed edges• Suppressed edges
• Non-manifold edges• Non-manifold edges
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ponent color and adds topology informationponent color and adds topology information
Surface edges are different from lines and are sometimes handledSurface edges are different from lines and are sometimes handled
of surface edges constitutes the geometric topology. Below the
topology is described (Note: the shown model is displayed via thetopology is described (Note: the shown model is displayed via the
Free EdgesFree Edges
Afree edge is an edge that is owned by only one surface. Free edgesAfree edge is an edge that is owned by only one surface. Free edges
On a clean 2D model consisting of surfaces, free edges appear onlyOn a clean 2D model consisting of surfaces, free edges appear only
holes.holes.
Note: Free edges that appear between two adjacent suNote: Free edges that appear between two adjacent su
two surfaces. The automesher will leave a gap in the meshtwo surfaces. The automesher will leave a gap in the mesh
Shared EdgesShared Edges
Ashared edge is an edge that is owned, or shared, by two adjacentAshared edge is an edge that is owned, or shared, by two adjacent
When the edge between two surfaces is a shared edge (this is whatWhen the edge between two surfaces is a shared edge (this is what
the two surfaces - they are geometrically continuous. The automesherthe two surfaces - they are geometrically continuous. The automesher
and will produce a continuous mesh without any gaps along thatand will produce a continuous mesh without any gaps along that
that cross over a shared edge.that cross over a shared edge.
Suppressed EdgesSuppressed Edges
A suppressed edge is shared by two surfaces but it is ignored by theA suppressed edge is shared by two surfaces but it is ignored by the
Like a shared edge, a suppressed edge indicates geometric continuityLike a shared edge, a suppressed edge indicates geometric continuity
automesher will mesh across a suppressed edge as if were not eautomesher will mesh across a suppressed edge as if were not e
length of a suppressed edge and, consequently, individual elementslength of a suppressed edge and, consequently, individual elements
effectively combining surfaces into larger logical meshable regionseffectively combining surfaces into larger logical meshable regions
Non-Manifold EdgesNon-Manifold Edges
Anon-manifold edge is owned by three or more surfaces. Non-maniAnon-manifold edge is owned by three or more surfaces. Non-mani
They typically occur at “T” intersections between surfaces or whenThey typically occur at “T” intersections between surfaces or when
places seed nodes along their length and will produce a continuousplaces seed nodes along their length and will produce a continuous
not construct any individual elements that cross over a T-joint edgenot construct any individual elements that cross over a T-joint edge
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handled differently for certain HyperMesh operations. The connectivityhandled differently for certain HyperMesh operations. The connectivity
the four types of surface edges which represents the geometric
2D Topo mode in HyperMesh).2D Topo mode in HyperMesh).
edges are colored red by default.edges are colored red by default.
only along the outer perimeter of the part and around any interioronly along the outer perimeter of the part and around any interior
surfaces indicate the existence of a gap between thesurfaces indicate the existence of a gap between the
mesh wherever there is a gap between two surfaces.mesh wherever there is a gap between two surfaces.
adjacent surfaces. Shared edges are colored green by default.adjacent surfaces. Shared edges are colored green by default.
what you typically want to have), there is no gap or overlap betweenwhat you typically want to have), there is no gap or overlap between
omesher always places seed nodes along the length a shared edgeomesher always places seed nodes along the length a shared edge
edge. The automesher will not construct any individual elementsedge. The automesher will not construct any individual elements
the automesher. Suppressed edges are colored blue by default.the automesher. Suppressed edges are colored blue by default.
continuity between two surfaces but, unlike a shared edge, thecontinuity between two surfaces but, unlike a shared edge, the
even there. The automesher does not place seed nodes along theeven there. The automesher does not place seed nodes along the
elements will span across it. By suppressing undesirable edges you areelements will span across it. By suppressing undesirable edges you are
regions.regions.
manifold edges are colored yellow by default.manifold edges are colored yellow by default.
when 2 or more duplicate surfaces exist. The automesher alwayswhen 2 or more duplicate surfaces exist. The automesher always
continuous mesh without any gaps along that edge. The automesher willcontinuous mesh without any gaps along that edge. The automesher will
edge. These edges cannot be suppressed.edge. These edges cannot be suppressed.
- Geometry In HyperMesh - Geometry In HyperMesh
SolidsSolids
A solid is a closed volume of surfaces that can take any shape. SolidsA solid is a closed volume of surfaces that can take any shape. Solids
tetra and solid meshing. Its color is determined by the component tetra and solid meshing. Its color is determined by the component
The surfaces defining a solid can belong to multiple componentThe surfaces defining a solid can belong to multiple component
controlled only by the component collector to which the solid belongs.controlled only by the component collector to which the solid belongs.
Below is an image of solid topology as well as a description of the three types Below is an image of solid topology as well as a description of the three types
To activate the 3D topology mode view, please activate the corresponding seTo activate the 3D topology mode view, please activate the corresponding se
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Solids are three-dimensional entities that can be used in automaticSolids are three-dimensional entities that can be used in automatic
ponent collector to which it belongs.ponent collector to which it belongs.
collectors. The display of a solid and its bounding surfaces arecollectors. The display of a solid and its bounding surfaces are
the solid belongs.the solid belongs.
the three types of surfaces which define the topology of a solid.the three types of surfaces which define the topology of a solid.
e the corresponding settinge the corresponding setting
- Geometry In HyperMesh - Geometry In HyperMesh
Bounding FacesBounding Faces
A bounding face is a surface that defines the outer boundary of a A bounding face is a surface that defines the outer boundary of a
bounding face is unique and is not shared with any other solid. A single bounding face is unique and is not shared with any other solid. A single
Fin FacesFin Faces
A fin face is a surface that has the same solid on all sides i.e. it actsA fin face is a surface that has the same solid on all sides i.e. it acts
default.default.
A fin face can be created when manually merging solids or when creating A fin face can be created when manually merging solids or when creating
Full Partition FacesFull Partition Faces
A full partition face is a surface that defines a shared boundary betA full partition face is a surface that defines a shared boundary bet
by default.by default.
A full partition face can be created when splitting a solid or whenA full partition face can be created when splitting a solid or when
intersecting locations.intersecting locations.
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a single solid. Bounding faces are shaded green by default. A a single solid. Bounding faces are shaded green by default. A
single solid volume is defined entirely by bounding faces. single solid volume is defined entirely by bounding faces.
acts as a fin inside of a single solid. Fin faces are shaded red byacts as a fin inside of a single solid. Fin faces are shaded red by
when creating solids with internal fin surfaces.when creating solids with internal fin surfaces.
etween one or more solids. Full partition faces are shaded yellowetween one or more solids. Full partition faces are shaded yellow
when using Boolean operations to join multiple solids at shared orwhen using Boolean operations to join multiple solids at shared or
- Geometry In HyperMesh - Geometry In HyperMesh
What You Need To KnWhat You Need To Kn
Green edges - 2 surfaces are stitched together; the FE mesh willGreen edges - 2 surfaces are stitched together; the FE mesh will
green edge.green edge.
Red edges - indicates free surface edges. Red edges inside theRed edges - indicates free surface edges. Red edges inside the
together (gap); the FE mesh will NOT be linked (not compatible).together (gap); the FE mesh will NOT be linked (not compatible).
Yellow edges — minimum of 3 edges are stitched together; the FE mesh willYellow edges — minimum of 3 edges are stitched together; the FE mesh will
Blue edges — Suppressed green edge. Surfaces are “melted“ togBlue edges — Suppressed green edge. Surfaces are “melted“ tog
and elements are placed across it.and elements are placed across it.
How to visualize the edgeHow to visualize the edge
colors?colors?
Display is controlled in the Visualization toolbar by activatingDisplay is controlled in the Visualization toolbar by activating
colored respectively) or Mixed (surfaces are displayed in their originalcolored respectively) or Mixed (surfaces are displayed in their original
Browser), edges are colored respectively.Browser), edges are colored respectively.