Introduction to ANSYS Meshing Module 3: Global Mesh …

1 Module 3: Global mesh ControlsIntroduction to ANSYSM eshingDr. Ahmed Nagib ElmekawyWhat you will learn from thispresentation Introduction to Global MeshControls Defaults General Sizing Controls & Advanced SizeFunctions GlobalInflation Assembly MeshingControls Statistics2 Global MeshControlsPreprocessingWorkflowSketche 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 Meshing3 Meshing Process in ANSYSM eshing45 Global mesh controls are used to make Global adjustment in the Meshing strategy, which includes sizing functions, inflation, smoothing, defeaturing, parameter inputs, assembly Meshing inputs,etc.

2 Minimalinputs Automatically calculates Global element sizes based on the smallest geometricentity Smart defaults are chosen based on physicspreference Makes Global adjustments for required level of meshrefinement Advanced Size Functions forresolving regions with curvatures and proximity ofsurfacesGlobal mesh Controls(1)Smart defaults! Global mesh Controls(2)Physics BasedSettings Physics and SolverPreferencesGlobal mesh SizingControls Relevance and RelevanceCenter Advanced SizeFunctions Smoothing and Transition Span AngleCenter Curvature NormalAngle Proximity Accuracy and Cells AcrossGapInflation Inflation Option, InflationAlgorithm CollisionAvoidance Maximum Angle, Fillet Ratio,SmoothingAssemblyMeshing Activation of CutCell/TetrahedronsMeshingPatch ConfirmingOptions Activation of Advancing FrontMethodAdvanced ShapeChecking Element midsidenodesDefeaturing Pinchbased Automatic MeshBasedStatistics mesh statistics, Qualitycriteria6 Global mesh Controls(3)7 Four options under PhysicsPreference CFD, Mechanical, Explicit andElectromagnetic Three options under Solver Preference when CFDisselected.

3 Fluent, CFX andPOLYFLOW mesh setting defaults are automatically adjusted to suitthe Physics Preference and SolverPreference Assembly Meshing is active only when Physics PreferenceisCFD and Solver Preference isFluentDefaults 8 Relevance and RelevanceCenter Useful for automatic Global Refinement or Coarsening of themeshDefaults :RelevanceCoarseFine0100-1000100-1000100 -100 RelevanceCenterMedium9 Controls the growth and distribution of mesh inimportant regions of high curvature or close proximity ofsurfaces FiveOptions: Off. Proximity andCurvature Curvature Proximity FixedSizing : Advanced SizingFunctionsSizing : Advanced Sizing Function(ASF)ExamplesASF:Curvature Determines the Edge and Face sizes based on Curvature NormalAngle Finer Curvature Normal Angle creates finer surface mesh Transition of cell size is defined by GrowthRateASF:Off The edges are meshed with Global ElementSize Then the edges are refined for curvature and 2 Dproximity At the end, corresponding face and volume mesh is generated Transition of cell size is defined byTransitionASF:Proximity Controls the mesh resolution on proximity regions in the model Fits in specified number of elements in the narrowgaps Higher Number of Cells Across Gap creates more refined surfacemesh Transition of cell size is defined by GrowthRate11 Sizing : Advanced Sizing FunctionExamplesASF.

4 Proximity &Curvature Combines the effect of Proximity and Curvature sizefunctionMore computationaltimeASF: Fixed + LocalSizings mesh is refined locally due to sizing (on 2 edges for that example) Elsewhere size is definedbyMax (Face)Size Transition of cell sizeisdefined by GrowthRateASF:Fixed Constant mesh sizethroughout No refinement due to curvature or proximity in the model Surface mesh is generated with specified Max Face Size Volume mesh is generated with specified MaxSize12 Sizing : ElementSizeElementSize Element size used for the entiremodel This size will be used for Meshing all edges, faces andbodies Default value based on Relevance and Initial SizeSeed User can input required value as per geometrydimensionsElement size option available whenAdvanced Size Function is notused13 Sizing : Min and MaxSizeMinSize Minimum element size that the size function willgenerate Some element sizes may be smaller than this size depending on the edgelengthMax FaceSize Maximum face size that the size function willgenerateMaxSize Maximum element size that can be grown in the interior of volumemeshMin Size Max Face Size MaxSizeMaxSizeMouse Pointer serves toestimate meshsizesMax FaceSizeMinSize14 Sizing : GrowthRate Define the ratio between sizes of adjacentcells On surfaces and inside thevolumesMeshsize:GR = : 1,263,297cellsGR = : GR = :587,026cells392,061cellsGrowth Rate = Rate = (Default)Growth Rate =.

5 Transition Controls the rate at which elementsgrow Two level control fortransition Slow (Default for CFD, Explicit), produces smoothtransitions Fast (Default for Mechanical and Electromagnetic), produces more abrupttransitions Hidden for sheet models, ignored for assembliescontaining sheets, when ASF isOnFastSlow16 Sizing :Smoothing Improves quality by moving locations of nodes with respectto surroundingnodes Three level control for smoothingiterations High (Default forExplicit) Medium (Default for Mechanical, Electromagnetic andCFD) Low For Cutcell Meshing , the Smoothing option controls thequality threshold at which it will start smoothing. High : Span AngleCenter Controls curvature based refinement for Edges Three options and corresponding span angle rangesare Coarse: 91 to60 Medium: 75 to24 Fine: 36 to12 CoarseMediumFine18 InflationInflation Used to generate thin cells adjacent toboundaries Required for capture of wall adjacent boundarylayers Resolve viscous boundary layer inCFD Resolve thin air gaps in Electromagneticanalysis Resolve high stress concentration regions inStructures Cells are created by inflating from the surface mesh into the volume (3d) or inflating from the boundary edge onto the face(2d) Options to controlgrowth19 Inflation : AutomaticInflation Threeoptions None Select this for manual inflation settings using localmeshcontrols ProgramControlled All the faces are selected for inflationexcept.

6 Faces scoped to a NamedSelection Faces with manual inflationdefined Faces in contactregions Faces insymmetry Faces that belong to a part or body that has a mesh method defined that does not support 3D inflation, such as hex-dominant Faces in sheetbodies All Faces in chosen Named Selection: can growinflationlayers from faces grouped in one namedselection20 Inflation : InflationOptionsFiveoptions:SmooTotalThi cknessMaintains constant total height ofinflation layerthroughoutFirstLayerThicknessMainta insconstantfirstcellheightthroughoutFirs tLayer ThicknessTotal ThicknessFirstAspectRatioLastAspectRatio First AspectRatioControls the heights of the inflationlayers by defining the aspect ratio of the inflations that are extruded from the inflationbaseLastAspectRatioCreatesinfla tionlayersusingthevaluesofthefirstlayerh eight,maximumlayers,andaspectratiocontro lsAll available for PC tets and AssemblymeshingSmoothTransitionMaintains smooth volumetric growth between each adjacent layer.

7 Total thickness depends on the variationof base surface mesh sizes(Default)Smooth TransitionthTransition21 Inflation : InflationAlgorithms TwoAlgorithms Post Pre Patch independent meshes usePostPostPreview Inflation is available only with PreAlgorithmPre Surface mesh is inflated first, then rest of the volume meshgrows Default method for Patch ConformingTetrahedrons First Tet grows then Inflation processstarts Tet mesh is undisturbed, if the inflation options arealtered Default option for Patch IndependentTetrahedrons22 Defeaturing Removes small geometry features meeting the tolerances using Pinch or/and Automatic mesh Based Defeaturing controls in order to improve the mesh quality. Not all Meshing methods can take advantage of thesecontrols Automatic mesh Based Defeaturing (AMBD) when it is On , features smaller than or equal to the value of Defeaturing Tolerance are removedautomaticallyAMBDOffAMBDOn23 Statistics Option to view the mesh qualitymetric Exhaustive list of quality metrics Orthogonal Quality mesh qualitymetrics Option to view the mesh Metricchart Intuitive controls available under mesh MetricChart Various options to explore under the Controls See Module5 fordetails24 Parallel StatisticCalculations Note that statistics can utilize multi-core machinestospeed up calculations inparallel Specify your core count in Tools > Options to allowthis Note that options set here will be remembered forfuturesessions so you can set physics preference default 3 Global MeshControls26 Module 4.

8 Local mesh ControlsIntroduction to ANSYSM eshing27 What you will learn from thispresentation Local mesh controls ( mesh sizing, Refinement, Matchcontrol, Inflation,etc) How to apply localcontrols? Effect of local controls onmeshLocal MeshControls28 PreprocessingWorkflowSketchesand 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 Meshing29 Meshing Process in ANSYSM eshing30 Local MeshControlsControl the meshlocally Depends on the mesh Method usedLocal mesh Controlsare.

9 Sizing For Vertex, Edge, Face andBody ContactSizing For Edge andface Refinement For Vertex, Edge andFace Mapped FaceMeshing ForFace MatchControl For Edge andFace Pinch For Vertex andEdge Inflation For Edge andFaceThe latest control added on a particularentityoverrides any priorcontrols31 SizingRecommended for locally defining the meshsizesYou can only scope sizing to one geometry entity type at atime Forexample:youcanapplysizingtoanumberofe dgesoranumberoffaces,butnota mixof edges Types of Sizingoption Element Size specifies average element edge length on bodies, faces oredges Number of Divisions specifies number of elements onedge(s) Body of Influence specifies average element size within abody Sphere of Influence specifies average element size within thesphereSizing options vary depending on the entity typechosenx xAdvanced Size Function inGlobal settings shouldbe disabledEntity/OptionElementSizeNumber ofDivisionsBody ofInfluenceSphere ofInfluenceVerticesxEdgesxxFacesxBodiesx xxRequiresaCoordinatesystemforthesphereO nly Element Size type is availablefor CutCellmeshing32 Sizing :EdgesEdge meshed withconstant element size of60mmSizingType:ElementSizeSizingType:N umber ofDivisionsEdge meshed with10 elementsThe Curvature Normal Angle and/or the GrowthRatemaybenotdisplayeddependingonth eASFused33 Sizing.

10 EdgesBias Type and BiasFactorSpecify the grading scheme andfactor Bias Type: grading of elements towards one end, both ends, or thecenter BiasOption: Bias Factor: is the ratio of the largest element to the smallestelement Smooth Transition: defined by Growth Rate which is ratio of size of an element with size of previous element. (Growth Rate = BiasFactor^(1(n-1))34 Sizing influence fromother globalsettingsBehaviorSoft: Sizing will be influenced by Global sizing functions such as those based on proximity and/or curvature as well as local meshcontrolsHard: Size control is strictly adheredto Transition between hard edges (or any edge with bias) and adjacentedge and face meshes may beabrupt Hard edges or edges with bias will override Max Face Size and MaxSize properties35 ElementSizeDefines the maximum element size on thefaceFace meshedwith constant element sizeSizing :FacesEdge curvatureis resolved36 ElementSizeDefines the maximum cell size on theBodySizing : Body(volume)Body meshed withmax cell sizedefinedWithbodysizingWithbody sizingCutCellmeshWithout bodysizingTetrahedronpatchconformingmesh Without bodysizing37 Sphere of Influence.)