Introduction to ANSYS Meshing Module 01 ... - …

1 Module 01:CoreSkillsIntroduction to ANSYSM eshingDr. Ahmed Nagib ElmekawyIn this lecture we willlearn: MeshingFundamentals ANSYS Meshinginterface Geometryconcepts Meshingmethods Diagnostics &Usability DisplayOption Mesh Statistics & MeshMetrics2 OverviewPreprocessingWorkflowGeometry Import / CreationGeometry Cleanup / ModificationsMeshingPreprocessingandSolu tion3 Mesh Process & CoursePlan4 CoreSkillsModule1 MeshingMethodsModule2 GlobalControlsModule3 LocalControlsModule4 Mesh QualityModule5 ANSYS Meshing is a component of ANSYSW orkbench Meshingplatform Combines and builds on strengths of preprocessing offerings fromANSYS: ICEM CFD, TGRID (Fluent Meshing ), CFX-Mesh,GambitAble to adapt and create Meshes for different Physics andSolvers CFD: Fluent, CFX andPOLYFLOW Mechanical: Explicit dynamics,Implicit ElectromagneticIntegrates directly with other WB systems5 What is ANSYSM eshingPurpose of theMesh Equations are solved at cell/nodallocations Domain is required to be dividedinto discrete cells(meshed)MeshRequirements Efficiency &Accuracy Refine (smaller cells) for high solution gradients and fine geometricdetail.

2 Coarse mesh (larger cells)elsewhere. Quality Solution accuracy & stability deteriorates as mesh cells deviate from ideal shapeMeshingFundamentals6 Fluid Flow (Fluent), StaticStructural,.. ANSYS Meshing is launched withinWorkbench 2ways:From AnalysisSystemsMeshFrom ComponentSystemsDoubleclick Mesh inthe Systemor right clickand selectEditLaunching ANSYSM eshing10 MeshMetricsGraphicswindowSectionPlanesMa nageviewsDetailsviewOutlineToolbarsUnits BarEntity DetailsBarMessagewindowWorksheetGraphica l UserInterface8 Three defaultsections Geometry Bodies CoordinateSystems Default global & user definedsystems Mesh Meshing operations (controls &methods) displayed in the order in which they areinsertedIn thetree Right clicking on anyobject launches a context sensitivemenu Example: contains commands to generate, preview, clear ObjectDetails Select an object (in theOutline) Related information to that object are displayed in the Details Viewbelow Ex: Select a body ( Fluid ) in theOutline Details of Fluid.

3 Contains graphical and geometricdetails To access meshingdetails Click the Mesh object or any of the insertedobjects The Details View provides options to review, edit,or inputvalues for every object in theTreeDetailsView10 Geometry composed of Multipleparts No connection between parts (no facesharing) Contact Region isautomaticallycreatedbetween2facesEach part meshed independentlyResults in do -CFXG eometry Configuration MultiplePartsContact -Mechanical11 Hexa: Concentration in onedirection Anglesunchanged Tetra: Concentration in onedirection Angleschange Prism: Concentration in onedirection AnglesunchangedHexa (involume)Prisms (nearwall)12 Geometry composed of multiple bodies in apart Depend on Shared Topology method (inDM) None Results in a no connection between the bodies (similartomultipleparts) AutomaticCommon faceacts as Interior Note: The CFX users will still get duplicate nodes at interface in CFX, which is fine for itssolverGeometry Configuration Multi-bodyPartsFaces in contact imprinted & fusedtoform a single face shared between 2bodiesResultsinConformalmesh13 Geometry composed of multiple bodies in apart ImprintsFaces areimprinted on each other like facesContactRegionisautomaticallycreated non conformal interfaceFor identical mesh on these faces, use Match Control Results in unconnectedmeshGridinterface-FluentGGI -CFXG eometry Configuration Multiple bodyParts14 Part/Bodybased Meshing occurs at part or bodylevel.

4 Meshing Methods are scoped to individualbodies. Method assignment can be automatic or manual. Bodies contained in onepartare conformallymeshed. 3D cellTypes First MeshingApproachPart/BodyMethods15 Tetrahedrons. Tetrasonly Sweep. Prisms &hexahedrons MultiZone. Mainlyhexahedron HexDominant Not forCFD Automatic. Sweep + PC Tet (Depends on bodies) or PCTetMeshing 3D Geometry(1) Second Meshing Approach (mainly for CFDusers)Cut CellMeshingAssemblyMeshing Meshes an entire model inone process. Assembly ofparts Performs booleanoperations. Volume filling, intersection & combination Does not require prior fluidbodydefinition or sharedtopology. Conformal mesh created across Generatemainly Hexahedrons TetrahedronsPart/Body Meshing & AssemblyMeshing notinteroperable16 Meshing 3D Geometry(2)Default meshdisplayTurning wireframe modeonTurning on Mesh display : Mesh display By Body Connection (New )19 Named Selections are groups of geometric or finite elemententities: Namedselectionscanbecreatedeitherbyselec tingthedesireditemsandclickingthe NamedSelection iconinthecontexttoolbarorRMB>NamedSelect ionORusingthenamedselectionworksheet(sho wnlater).

5 Named selections must be composed of like entities (all surfaces or all edges, all nodes,etc.).RMBN amed Selections(1)18A new criteria selection can be based on an initialselection: Make an initial selection followed by a RMB > Create NamedSelection . Note, initial selection must be a >Selection here will create the first rowof to nodal named Selections(2)19In many detail window fields Named Selections can be referenceddirectly: In the Details view, change Scoping Method from Geometry Selection to Named Selection Select the Named Selection from the pull-downmenu A named selection toolbar provides quick access to basic controls View > Toolbars >Named Selections :Named Selections(3)20 Usability: Option to save mesh out to separate file (New ) When Save Mesh Data in Separate File is on the mesh is saved as a separate file(*.acmo). Duplication, Resume, Replace, and Save will handle the separate database and acmofiles.

6 Clear generated data will not remove the acmo file. Resetwill remove the acmofile. Design Points (also w/RSM) support the separate database and functionality is particularly helpful onLinuxto keep file sizes : Better Meshing Status Progress is reported as parts are meshed inparallel As a part is meshed the topology (edges, faces, bodies) are highlighted to show what is being workedon This can be turned off by unchecking Highlight If user stops Meshing , entity will stay highlighted, allowing user to find problematic geometryeasierIf user stops Meshing , parts that have been meshed are done. Restarting Meshing resumes only with unmeshedparts22 Mesh controls can now be grouped foreasierorganization Option: Group All Similar Children, will group all objects based ontype Options to suppress, rename, nest groups, ungroup, delete objects ingroup Drag and drop capabilities to modify thegroupingUsability: Folders for Meshing Controls Displays mesh color by qualitymetrics Options to probe quality or showmin/max Contour band can beadjustedDisplaymeshcontoursFind MinorMaxvalueProbeElementValues29 Display Option.

7 Color byqualityDisplays internal elements of themesh Elements on either side of plane can bedisplayed Toggle between cut or whole elementsdisplay Elements on theplaneEdit SectionPlanebuttoncan be used to drag section plane to newlocation Clicking on Edit Section Plane button will make section plane s anchor toappearMultiple section planes areallowedFor large meshes, it is advisable to switch to geometry mode (click on geometry in the Tree Outline), create the section plane and then go back to meshmodelSection Planes(1)39 Section Planes(2) Shaded section planes (New ) Shaded or hollow sectionplane Plot by body color or same color for sectionplane26 Displays mesh information for Nodes andElements List of quality criteria for the MeshMetric Different physics and different solvers have different requirements for meshqualityMesh metrics available in Workbench Meshinginclude: ElementQuality AspectRatio JacobeanRation WarpingFactor ParallelDeviation Maximum CornerAngle Skewness OrthogonalQualityFor Multi-Body Parts, go to corresponding body in TreeOutline to get its separate mesh statistics perpart/bodyMesh Statistics & MeshMetrics27 Displays Mesh Metrics graph for the element qualitydistribution Different element types are plottedwithdifferent colorbars Can be accessed through menu bar using Metric Graphbutton Axis range can be adjusted usingcontrols button (details nextslide) Click on bars to view corresponding elements in the graphicswindow Use to help locate poor qualityelementsMesh MetricGraph28 Mesh Metric GraphControls Elements on Y-Axis can be plotted with two methods.

8 Number ofElements Percentage ofVolume/Area Options to change the range on eitheraxis Specify which element types to include ingraph Tet4 = 4 Node LinearTetrahedron Hex8 = 8 Node LinearHexahedron Wed6 = 6 Node Linear Wedge(Prism) Pyr5 = 5 Node LinearPyramid Quad4 = 4 Node LinearQuadrilateral Tri3 = 3 Node LinearTriangle Te10, Hex20, Wed15, Pyr13, Quad8 & Tri6 non-linear elementsFor more information about the different mesh metrics please consult Module 05: MeshQuality29 What have we learnt in thissession: The global process to run ANSYSM eshing On overview of the interfaceand The various Geometryconfigurations Multipleparts Multi-bodyparts Multiple bodyparts Meshingmethods Part/bodybased Assemblymeshing SectionPlanes Diagnostics &Usability Mesh Statistics & MeshMetrics DisplayoptionAnd theassociatedshared topologyoptionSummary30 Workshop CFD ANSYS WB MeshingBasics31 Workshop FEA ANSYS WB MeshingBasics32 Module 2: Meshing MethodsIntroduction to ANSYSM eshingMeshingMethods34 What you will learn from thispresentation Meshing Methods for Part/BodyMeshing Assembly Meshing coveredseparately Methods & Algorithmsfor.

9 TetrahedralMeshing HexMeshing 2 DMeshing Meshing MultipleBodies SelectiveMeshing Recording MeshingOrderPreprocessingWorkflowSketche sand PlanesGeometryImport Options3 DOperationsDirect CAD/Bi-DirectionalCADG eometry Cleanupand RepairAutomatic CleanupMerge,Connect, Projection, Flow Volume Extraction,etcExtrude,Revolve, Sweep,etc3 DOperationsBoolean, Body Operations,Split, etcMeshingMethodsHybrid Mesh:Tet, Prisms,PyramidsHexaDominant, SweepmeshingGlobalMesh SettingsLocalMesh SettingsSizing, Body/Sphere of Influence,Match Control,etcGeometryCreation ORGeometryImportGeometry OperationsMeshingSolverAssembly Meshing35 Why MultipleMethods? Choice can dependon; Physics Geometry Resources Mesh could require just one ora combination ofmethods. Example Typical mesh design based on geometric, physicsand aspect ratio cells (Inflation) near wall to capture boundarylayer gradientsTet (3d) or Tri (2d) cells used here to mesh complexregionHex (3d) or Quad (2d) cells used to mesh simple regionsCells refinedaround small geometric details and complex flow36 In the Outline, right click Mesh, Insert >Method Select body in DetailsView Or, in the Graphics Window, Select body(s) ,right click, Insert >Method Body automatically selected in DetailsView Method is selectable using the drop downbox Select, Automatic, Tetrahedrons, HexDominant,Sweep orMultizoneInsertingMethods37 MethodBehavior Generates tetrahedral elements -two algorithms are available: PatchConforming PatchIndependent38 TetrahedronsMethodMethod & AlgorithmBehavior Bottom up approach.

10 Meshing processstarts from edges, faces and thenvolume All faces and their boundaries arerespected (conformed to) andmeshed Good for high quality (clean) CADgeometries CAD cleanup required for dirtygeometry Sizing is defined by global and/or localcontrols Compatible withinflationAccess Insert Method and set toTetrahedrons Additional drop down box for algorithmchoiceappears -Set to PatchConformingTetrahedrons Method: PatchConforming39 Method & AlgorithmBehavior Top down approach: Volume meshgenerated first and projected on to faces andedges Faces, edges and vertices notnecessarily conformedto Controlled by tolerance and scoping of Named Selection, load or otherobject Good for gross de-featuring of poorquality (dirty) CADgeometries Method Details contain sizingcontrols Compatible withinflationAccess Insert Method and set toTetrahedrons Additional drop down box for algorithm choice appears -Set PatchIndependentTetrahedrons Method: PatchIndependent40 Tetrahedrons Method:AlgorithmComparison (SurfaceMesh)Geometrycontaining smalldetailsPatch Conforming:All geometric detail is capturedPatch Independent:Can ignore and defeature geometryTetrahedrons Method:AlgorithmComparison (VolumeMesh)Geometrycontaining smalldetailsPatchConforming:Delaunaymesh smoothgrowthrate42 Patch Independent.