Workshop 13 Quad Meshing of a Stamped Part

Create a Project Choose “Open Project“ Icon Browse to the desired working directory Enter the project name Type in the File name as: StampedPart.prj Tips: The pull down next to the file name can be used to quickly locate recently used 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 will contains information about project settings, the working folder and file associations. Once the geometry, mesh, boundary conditions, parameter files etc. are saved with the project file, simply loading the project file will also load these associated files.

Import Geometry Stamped Part Variable thickness Import The Geometry: File -> Import Geometry -> Parasolid Select Stamped_VariableThickness.x_t Open Geometry is initially displayed with only curves Use the triad in the lower right corner to reorient the model to isometric view Stamped Part Variable thickness

Display Tree Display Geometry Display the Geometry: Geometry display is controlled by the model tree on the left Expand the ”Geometry“ Branch with a left click on the + sign Display: Surfaces by left mouse click on icon Display: Solid & Wire mode by right mouse click on Surfaces in Display Tree Display: Transparent mode by right mouse click on Surfaces in Display Tree Display Tree

Import Geometry Scale the Geometry: #1 #2 Scale the Geometry: Geometry => Transform Geometry => Scale Geometry Select: Surfaces with window drag box or “a” hotkey Set: Scale Geometry X, Y and Z factors to 1000 Apply Measuring the model reveals that its units are in meters, a side effect of Parasolid translation, lets scale to millimeters. The geometry may appear to disappear, it has simply grown off the screen. Use the “x” hotkey or zoom extents utility icon. Now the models units are in mm and we can use whole numbers instead of decimals

Build Topology BUILD TOPOLOGY: #1 BUILD TOPOLOGY: Geometry -> Repair Geometry -> Build Diagnostic Topology Default: Tolerance is auto-calculated as 0.2 Default: New Part Name is set to Inherited Accept all defaults and press Apply Observe: Because the New Part Name is set to Inherited Curves & Points will be in the Part of the associated surfaces Set: Surface display to wire frame using the display tree or Wire frame Icon #2 #3 #4 Note: Yellow lines would indicate (single edges) a hole. Tips: set a reasonable tolerance based on model size By default, tolerance is set to 1/1000th the size of the model bounding box diagonal, rounded Use Part by part option if you are working with an assembly #5 #6

Midsurface MID SURFACE: #1 MID SURFACE: use the “Measure Distance” Tool to determine the thickness of the part. At its widest point, it should show approximately 6.0 depending on how actually you place the measure points We will want to set a “Search distance” greater than this distance, 6, to cover tolerances and measurement inaccuracies #2 1.0 thick 6.0 thick #3 Geometry -> Create/Modify Surface -> Midsurface Search Distance = 7 To quickly midsurface based on the Search distance, set “How” to Quiet default selection method; “By Parts”, use the Select Parts Popup to select PS and Accept Press Apply #4 #5 #6 #7 New Mid-surfaces displayed with original curves. Build Diagnostic Topology will remove unattached curves #8

Build Topology #1 #2 Initially after midsurfacing, the original curves remain, but unattached to any surfaces. Build Diagnostic Topology removes unattached curves and establishes connectivity between new surfaces #3 BUILD TOPOLOGY: To clean up the unattached curves and reestablish connectivity… Geometry -> Repair Geometry -> Build Diagnostic Topology Tolerance value = 0.2 and press Apply #4 Build Topology Red curves indicate 2 edges meet within the tolerance. Yellow curves indicate a single edge, the perimeter and hole curves are yellow #5

Part Mangement Note: if you accidentally deleted everything, UNDO! The original surfaces in the PS part have all been deleted. The new mid surfaces are in the SURFS part. New to 5.1, we now have the option to delete a Part directly from the tree, even if it still contains entities. Manage Parts: In the model tree, RMB on the specific Part to be deleted. From the pull-down, select Delete If entities still exists in that part, you are prompted to delete them. You must delete or move the entities to another part before that part can be deleted. Other options, such as renaming parts, are also available by right clicking on each part You can still delete all the empty parts after right clicking on “Parts”. #3 #1 #2 Note: if you accidentally deleted everything, UNDO!

Set Mesh Sizes Assign Element Size: #1 #2 Assign Element Size: Use the new Mesh Parameters option to: Mesh -> Set Curve Mesh Size Using the By Selected Curves Method, and the curves select picker, select all the curves with the “a” hotkey Set; Maximum Element size to 4 Defaults; accept all the other defaults press Apply. #3 #4 NEW: Increment/Decrement element count on a particular curve by mouse clicking. With this new feature, the user selects a curve and then left or right clicks the mouse on that curve to adjust the number of nodes. #5

Display Mesh Sizes Display Element Size: Right Click on Curves Turn on Curve node Spacing and/or Curve Element Count Curve Node Spacing is displayed as tick marks along the curves. These indicate points of node seeding for patch based meshing. Curve Element Count displays the number of elements on each individual curve RMB on Curves Curve Element Count Note: These curve mesh size indicators can be used together or separately Curve Node Spacing

Set Mesh Sizes Advanced Curve Mesh Sizes: #1 #2 Advanced Curve Mesh Sizes: Mesh -> Set Curve Mesh Size Using the By Selected Curves Method, and the curves select picker, select just the bolt hole curves (2 per) Change the Method to Element Count Set; Number to 6 Number of elements per curve segment Set; Height to 3 Height of first quad ring normal to curve Set; Width to 1 Number of quad rings press Apply. #3 #4 #5 #6

Surface Meshing SHELL MESHING: Click on Mesh => Mesh Shell icon #1 #2 SHELL MESHING: Click on Mesh => Mesh Shell icon Use the Patch Dependent sub-icon Default; Mesh Type Quad dominant Default; Method From Surfaces Select all Surfaces with “a” hotkey Make sure that Project to Surfaces is checked Set Ignore Size = 1 Features below 1 units will be suppressed Accept other defaults Apply #3 #4 #5 #6 #7 #8 #9

Dormant Curves #1 #2 The previous mesh had too many patches, although ignore feature size fixed the worst issues, it is often helpful to have greater patch independence. #3 BUILD TOPOLOGY, w/ Filter: Geometry -> Repair Geometry -> Build Diagnostic Topology Tolerance value = 0.2 Default; Feature Angle 30 Turn on Filter Points and Filter Curves press Apply Build Topology w/ Filter Curves Display Dormant Curves #4 #5 Yellow curves indicate a single edge. Red curves that met at less than 30 degrees were removed. Grey Curves (NEW) are dormant curves, used to sew together otherwise separate patches. Activate dormant curves display through RMB on curves

Mesh From Surfaces Regenerate Mesh: File => Mesh => Close mesh To remove previous Mesh => Mesh Shell => Patch dependent Keep all previous settings and Apply This is now using all the surfaces as one large patch. Mesh walks across the internal surface boundaries. Lets bring back, “Restore”, some of these dormant entities to better control our patches.

Restore Dormant Curves #1 #2 #3 Re-establish patch dependence by restoring some/all of these dormant entities #5 Restore Dormant Entity: Geometry -> Restore Dormant Entities Select the appropriate Curves Selecting individual curves captures the nodes along those curves Restoring a complete loop of curves results in patch dependence within the loop Apply Select these feature curves and they will turn red #4 Red curves are now captured. Grey curves are still ignored by the mesh Mesh Shell with previous settings Don’t forget to select these tiny curves to completely separate the Patch

Make Curves Dormant #1 #2 #3 To make an active curve “dormant”, use delete curve. Delete Curve: Geometry -> Delete Curve Select the appropriate Curves Removing the curves on one side of each fillet effectively joins the fillet and adjacent surface patches into one patch Apply #5 #4 Deleted curves become dormant (Grey) and are ignored by the mesh Mesh Shell with previous settings

Free Style #1 Use a combination of Topology filters, restoring dormant entities and delete curves to control patch dependence Take a few minutes to try different things. #2 #3 Active curves within a patch are also captured Behind the scenes. Surfaces sharing dormant curves are grouped and meshed with the from surfaces option, while surfaces surrounded by active curves are meshed with the from each surface option. Active curves within a surface or group of surfaces are treated like collapsed internal loops. Closed loops of Red Curves or from surface edge to surface edge separate out a patch.

Calculate and display surface thickness #1 #2 The surface thickness was automatically established during midsurfacing. This thickness needs to be transferred to the new shell mesh #3 Adjust Mesh Thickness: Edit Mesh -> Adjust Mesh Thickness Set the method to Calculate This determines the element thickness on a node by node basis from the surface thickness at each node’s location. Apply #4 Display Mesh Thickness: RMB on Shells in the model tree Activate Shell Thickness #5 Thickness is calculated at each node and displayed normal to the surface in both directions Varying thickness is auto applied to shell element properties for generic output