文稿案例2021-06学习icemgeom

1、Workshop 2.1Geometry Repair Engine BlockIntroduction to ANSYSICEM CFDCreate a ProjectChoose File New ProjectBrowse to EngineBlock working directoryEnter the project nameType in the File name as: Engine_block.prjSaveTips: The pull down next to the file name can be used to quickly locate recently used

2、 projects.In Windows, The File browser is a standard Windows file browser offering all the functionality of windows explorer.In Unix or Linux, similar functionality is also available.The Project file contains information about project settings, the working folder and file associations. The geometry,

3、 mesh, boundary conditions, parameter files etc. are saved with the project file.Simply loading the project file will also load these associated files.Open GeometryRead in the geometry:File Geometry Open Geometry Select: engine_block.tin using the File Browser and OpenRMB on surfaces in the Model tr

4、ee and select Solid Rotate the model and you can see that this geometry has missing surfaces, holes, gaps, overlapping surfaces, and untrimmed surfacesBuild Diagnostic Topology checks the geometry for imperfections within a user defined tolerance. Measure the size of the smallest feature on the geom

5、etry or any visible gaps. Make sure that the tolerance is small enough to keep important details in the geometry. Rule of thumb: 1/10th to 1/5th of the smallest mesh size, or 1/10th of the smallest geometry featureGeometry Repair Geometry Build Diagnostic TopologySet Tolerance = 0.05Accept all other

6、 defaultsClick ApplyBuild Diagnostic TopologyMeasure distance#1#2#3#4Remove HolesYellow curves indicate a gap or holeGeometry Repair Geometry Remove holesSelect the four boundary curves on the holes shownMiddle mouse click, and this will perform the functionAutomatically removes holes by untrimming

7、the surface there#1#2#3Close HolesKey lConfirm with key yGeometry Repair Geometry Close holesSelect any one of the boundary curves on the hole shownPress “l” (lower case L) on the keyboard or Select all items attached to current selection in the Select geometry toolbarSelects all curves within a set

8、 angle attached to the selected curve (“flood fill”) Selection restricted to yellow (single edge ) curvesMiddle mouse to accept Press “y” to accept the surfaceMiddle mouse to exit selectionMiddle mouse#1#2Select all items attached#3Sets angle of flood fillGeometry Repair Geometry Stitch/Match edgesS

9、elect two opposite curves to close the gap in the location shownMiddle mouse to acceptWhen prompted press “t” to select trimPress “y” to accept, if it looks correctRepeat for 3 more pairs to close the gap. Middle click when done.Rerun Build Topology in order to update the connectivity (tol=0.05)Stit

10、ch/Match Edges Extend#1#2#33 other pairs were doneChange method to Extend/TrimThis is the same method as previously by pressing “t” with user select, but without confirmationSelect the first 2 curves as shown at the lower right picture, and middle mouse clickRerun Build Topology (tol=0.05) to update

11、 the connectivity if any of these curves turn green (unattached)Order is important: first curve tries to move to second curveRepeat for a total of 4 pairs of yellow curvesSelect secondSelect firstSelect firstSelect secondStitch/Match Edges - TrimGeometry Repair Geometry Stitch/Match edges#1#2#3#32 m

12、ore curve pairs were done hereGeometry Create point Project Point to CurveThis location is similar to what is seen with IGES import oftenThe surfaces will next be matched which will bend the surface of the first curve to match the second curve. Therefore, the curve ends must be fairly close or else

13、the surface gets greatly distortedThe large curve will need to be segmented at these pointsFirst select the long curveThen select these 2 points and middle mouse click twice (2nd time exits selection)Two points were createdProject Point to Curve#1#2#3Segment CurveGeometry Create/Modify Curve Segment

14、 CurveMethod = Segment by pointPick the long curve firstThen select the two points on the curveMiddle mouse click to finishAny function that highlights a curve will show it is segmentedRight click to cancel#1#2First select curveThen select the 2 points on the curve#3Stitch/Match Edges MatchGeometry

15、Repair Geometry Stitch/Match edgesSet Method back to User SelectSelect two opposite curves to match the surface boundaries as shown below, and middle mouse click.If you get an error, “cant get endpoints of curve,” build topology againIncrease the value of “Max gap distance” to 0.2 if it doesnt work

16、with value 0.1When prompted press “m” to select matchThe surface of the first curve will be stretched to meet the second curveRepeat for 2 more pairs to close the gapRerun Build Topology in order to update the connectivitySelect firstSelect second#1#2#3#4Close GapsGeometry Repair Geometry Stitch/Mat

17、ch edgesFirst change surface display to wireframeSet Max gap distance to 2.0Select all curves (box select and middle mouse or press “a”)Each single curve pair within the defined gap distance will be presented automatically. Choose the option “fill,” key “f” and confirm with “y”. For example:Skip ver

18、y tiny gaps by the option no change: key “n”. For example:In this workshop you will have to use the fill option to create five surfaces and ignore two tiny gaps using no change option#1#2#3#4Middle mouse click when doneClose GapsIncrease the gap distance to 2.5, enter curve selection again and selec

19、t all curves.Geometry Repair Geometry Stitch/Match edgesSet Max gap distance to 2.5Select all curves “a”When presented, skip the 2 tiny gaps by option “n”, no change, until a larger gap appears between a longer and a shorter curve. Use the option set partial - key “p”, and then fill - key “f”, confi

20、rm with “y”.Use the option no change, “n” when presented with more curves, or “x” to cancel further curve pairs.Press “p” for set partialThen press “f” for fill#1#2#3Do NOT fill this one. The wrong curves will be highlightedSelect Geometry Repair Geometry Build Diagnostic TopologyKeep Tolerance = 0.

21、05Toggle on Split surface at T-connections if it is not on alreadySurfaces automatically trimmedIf build topology was already run with this option on then the surfaces are already segmentedClick ApplyDelete the 3 surfaces that extend outside the volume as shownBuild Topology: Split surfacesHidden su

22、rface see next slideThe overhanging surfaces are easily found at the blue (multiple) curves#1#2#3#4#5Delete Surface from Previous SlideTo select surfaces in backgroundIf hard to view “hidden” or background surface, turn on Transparent modeRMB Surfaces in model treeCant select “through” solid surface

23、 in foregroundEven when transparentTurn on Wire FrameYou can select through foreground surfaces by selecting parametric line of background surfaceOr blank surface in foreground in solid displayThen select interior surface to deleteBuild TopologyBuild topologyRMB on curves and select Show Double. Thi

24、s will turn off all double (red) curves. Double curves are connected to 2 surfacesTurn off surfaces and pointsGeometry Repair Geometry Build Diagnostic TopologySet Tolerance = 0.05Toggle on Single curve clean up and enter a tolerance of 0.5 (always a bigger number than the first tolerance)Thin gap r

25、egions less than 0.5 will be ignoredSliver features greater than 0.05 will be retainedToggle on Split surface at T-connections (if not ON)Accept all other defaultsPress ApplyNote unattached curves (green) are automatically deleted and some yellow curves disappeared#1#2#3#4#5#6#7Close HolesGeometry R

26、epair Geometry Close HolesToggle on Multiple holesBox select the curves that bound the two holes shown and middle mouse clickWhen prompted press “y” to accept each created surfaceMiddle mouse click afterward to exit selection#1#2#3#4Make sure background is not white in order to see the highlighted s

27、urface, Settings Background StyleCreate SurfacesFirst turn surfaces back onGeometry Create/Modify Surfaces Curve DrivenTurn Inherit part OFFEnter the part name as CUTPLANESelect the driving and the driven curve as shownOnly need to middle mouse click after driven curveMiddle mouse click again after

28、the surface is created in order to exit selection modeDriven curveDriving curve#1#3#4#6#2#5Trim SurfaceGeometry Create/Modify Surfaces Segment/Trim surfaceSelect the CUTPLANE surface, middle clickSelect the single curves (yellow) shown to trim the surface and middle mouse clickThe surface is split i

29、nto 4 separate surfacesThe surface segmenting can also be done by running Build Topology with Split surface at T-connections toggled ONDelete the 3 unwanted surfaces afterward#1#2#3#4#5Delete surfaceDelete UnattachedGeometry Delete CurveToggle on Delete UnattachedNo curves need to be selected. All u

30、nattached curves will be deletedPress ApplyAn unattached point is still leftGeometry Delete PointToggle on Delete UnattachedPress ApplyBoth these operations can be done by Build Topology with Delete unattached curves and pointsSave Project#1#2#3#4#5#6#7Further InvestigationFor those that have the ti

31、me, the following pages introduce additional conceptsRemove holes instead of close holesOther stitch methodsManually make a better shaped surfaceClose/Remove HolesOpen the original geometry again, build topology, and try these further exercisesInspect the difference between using close holes and rem

32、ove holesYou will need to put surfaces in wireframe to see the differenceClose holes fills with new surfacesRemove holes redefines the existing surfaceClose Hole with Better ShapeView the filled surface carefully, and you will see a strange bumpTo get a better shape, you will need to fill this hole

33、with multiple smaller surfaces and create a curve though the worst area to explicitly define the surface curvature thereTo do this, first project the point to the curve shown and then segment the curve. Project this point to this curveThen segment the curve at the new pointClose Hole with Better Sha

34、peYou will need to create a spline “from points” or a 3-point “arc”You will have to select off geometry in space for one of the points, but selecting in space will select on one of the 3 base planes (XY, YZ, XZ) going through the originSo this will require you to create a local coordinate system whi

35、ch defines new base planesUse this icon to create a local coordinate system using the 3 point method1st point is the origin, 2nd point is the Z axis, and the 3rd point defines the XZ plane (shown below)1st2nd3rdThe current local coordinate system is activated in the model treeClose Hole with Better

36、ShapeCreate a curve with the “from points” or “arc” method (investigate the difference)The yellow dot will jump to the nearest point when you select at the ends. When you select in space for the middle location it will select on the base plane in the local coordinate system closest to the screen pla

37、ne1st2nd3rdThen use the close holes button to select the curves for half of the holeOther Stitch MethodsTry the other stitch methods at this slotFillBlendEnforces surface tangency at curvesMatchMatch looks like extend/trim, but its not the same. Match adjusts surface curvature while extend/trim just

38、 extends or trims along the current surface shapeFillBlendMatchDifferent Length Curves Investigate what happens with all the stitch/match methods when the selected curves have greatly different lengthsMatchExtend/trimFillBlend2nd curve1st curveSurfaces shown in wireframe/fullThis is the match example without segmenting the curves first.The first surface is stretched so that the full length of the first curve matches up to the full length of the second curve.This shows that cur