Скачать презентацию

Идет загрузка презентации. Пожалуйста, подождите

Презентация была опубликована 3 года назад пользователемАртем Лошкомоев

1 S3-1PAT301, Section 3, October 2003 SECTION 3 GEOMETRIC MODELING

2 S3-2PAT301, Section 3, October 2003

3 S3-3PAT301, Section 3, October 2003 BASICS & DEFINITIONS

4 S3-4PAT301, Section 3, October 2003

5 S3-5PAT301, Section 3, October 2003 n MSC.PATRAN combines topological structures to define geometry n The topological entities within MSC.PATRAN are n Vertices hold positions for an edge, face, and body n All topological entities can be cursor selected to perform MSC.PATRAN functions (e.g. Surface 10.2) TOPOLOGICAL STRUCTURES Vertex Edge Face Body

6 S3-6PAT301, Section 3, October 2003 CASE STUDY: TOPOLOGY OF SIMPLE SOLID n Create a 1x1x1 blue parametric solid u Click the Geometry Applications button. u Set Action/Object/Method to be Create/Solid/XYZ. u Apply. u Turn on the solid labels using

7 S3-7PAT301, Section 3, October 2003 n Your model should now appear as follows CASE STUDY: TOPOLOGY OF SIMPLE SOLID Solid 1Exploded View Look at topological definition

8 S3-8PAT301, Section 3, October 2003 CASE STUDY: TOPOLOGY OF SIMPLE SOLID n Display Point and Solid labels u To display the labels, click on the following icon

9 S3-9PAT301, Section 3, October 2003 CASE STUDY: TOPOLOGY OF SIMPLE SOLID n First, look at how the solid faces are topologically labeled Solid 1.2 Solid 1.4 Solid 1.6

10 S3-10PAT301, Section 3, October 2003 n Next, look at solid edges, e.g. Solid u In this example six edges are picked CASE STUDY: TOPOLOGY OF SIMPLE SOLID

11 S3-11PAT301, Section 3, October 2003 n In preparation to create a point using a solid vertex delete Point 7. u Under Geometry set Action to Delete. u Set Object to Any. u Select Point in the Select Menu. u Select Point 7 for Geometric Entity List. u Apply. CASE STUDY: TOPOLOGY OF SIMPLE SOLID

12 S3-12PAT301, Section 3, October 2003 n Create a point at a vertex where Point 7 was. Notice that there are six coincident vertices, with one vertex per solid edge. u Set Action/Object/Method to Create/Point/XYZ. u Enter vertex Solid in Point Coordinates List. u Apply. CASE STUDY: TOPOLOGY OF SIMPLE SOLID

13 S3-13PAT301, Section 3, October 2003 CASE STUDY: TOPOLOGY OF SIMPLE SOLID n Create parametric surfaces from the parametric solid, e.g. one surface for u=0.5 u Set Action/Object/Method to Create/Surface/Extract. u Set the u Parametric Value to 0.5. u Select Solid 1 for Solid List. u Apply. u Repeat these steps for v=0.5 and w=0.5.

14 S3-14PAT301, Section 3, October 2003 n Now can just look at the parametric surfaces within the solid by erasing the solid. u Display/Plot/Erase. u Enter Solid 1 for Selected Entities. u Erase. CASE STUDY: TOPOLOGY OF SIMPLE SOLID

15 S3-15PAT301, Section 3, October 2003 n Shade the three surfaces. u Click on the following icon. n What are the parametric coordinates of the point at surface intersection? u Ans: (0.5, 0.5, 0.5) CASE STUDY: TOPOLOGY OF SIMPLE SOLID

16 S3-16PAT301, Section 3, October 2003 GEOMETRY BUILDING BLOCKS POINT (CYAN) n A point is a 0 dimensional CAD entity. It represents a location in space. n MSC.PATRAN creates points automatically when constructing curves, surfaces, and solids Points are created at vertices, e.g. surface vertices (corners) It is not always necessary to construct entities starting with their points, e.g. surface from points X Y Z 9 Y Z X

17 S3-17PAT301, Section 3, October 2003 GEOMETRY BUILDING BLOCKS(Cont.) A curve is a general vector function of the single parametric variable 1 ; it can have many types of mathematical forms: Curve (Yellow) (X,Y,Z) = function ( ) A curve has: Two points, with one at each end A parametric coordinate ( 1 ) whose domain is from 0.0 at P1 (its origin) to 1.0 at P2 Meshed with bar elements P2 P1 P( ) Z Y X Z X Y 5 5 Bar Element

18 S3-18PAT301, Section 3, October 2003 GEOMETRY BUILDING BLOCKS (Cont.) Surface types can be simple (Green) or complex/general (Magenta) A simple surface is a general vector function of the two parametric variables 1, 2 : Surface (Simple or complex) (X,Y,Z) = function ( 1, 2 ) A simple surface has: 3 or 4 bounding edges A parametric origin and parametric coordinates whose domains are from 0 to 1 A simple surface with 3 visible edges has a fourth edge that is degenerate 12P2 P1 P4 P3 Z Y X Z X Y P( )

19 S3-19PAT301, Section 3, October Display Line for visualizing surface 1 3 Surface 1 IsoMesh Mesh of Surface 1 Nodes follow curves of constant parametric value GEOMETRY BUILDING BLOCKS (Cont.) SURFACE (Cont.) n A simple surface can be meshed with either the IsoMesh (mapped) or Paver (free) meshers

20 S3-20PAT301, Section 3, October 2003 General Trimmed Surface (8 edges) Paver Mesh of Surface Perimeter of surface GEOMETRY BUILDING BLOCKS (Cont.) SURFACE (Cont.) n A complex or general trimmed surface (magenta) has more than 4 edges (N-sided) and can have inner boundaries u Not defined parametrically, e.g. 1, 2 not used u It is a trimmed parametric surface u Must be meshed with the Paver mesher l Meshes perimeter of surface first

21 S3-21PAT301, Section 3, October 2003 Y Z X GEOMETRY BUILDING BLOCKS (Cont.) SOLID (SIMPLE OR COMPLEX) n Simple or parametric solid (blue) u Vector function of the three parametric variables 1, 2, 3 n A simple solid has: u 4 to 6 bounding faces u Parametric origin and coordinates whose domains are from 0 to 1 n A simple solid with 4 to 5 visible faces has some degenerate faces n Parametric solids are meshed with the IsoMesh (mapped) mesher to generate hex, wedge, or tet elements P 8 P 7 P 6 P 4 P 3 P 2 P 1 P 5 P

22 S3-22PAT301, Section 3, October 2003 Tetrahedral Mesh B-Rep Solid GEOMETRY BUILDING BLOCKS (Cont.) SOLID (Cont.) n Complex or non-parametric solids (N-faced) (white) u Non-parametric solids can be either Patran native B-Rep (boundary representation) or parasolid B-Rep u CAD solids can be accessed as Patran native B-Rep or parasolid B-Rep solids, and can be meshed using the automatic TetMesh algorithm l Meshes faces with tri-s, then perimeter of solid with tet-s first l Similar to Paver mesher

23 S3-23PAT301, Section 3, October 2003 Plane Vector GEOMETRY BUILDING BLOCKS (Cont.) PLANES, VECTORS n Infinite planes and vectors are used for certain geometric operations, such as solid break by a plane n A plane is uniquely defined by vector representing its normal and a point on the plane n A MSC.PATRAN vector quantity is defined by a magnitude, a direction and a point of origin

24 S3-24PAT301, Section 3, October 2003

25 S3-25PAT301, Section 3, October 2003 IMPORTING AND EXPORTING GEOMETRY

26 S3-26PAT301, Section 3, October 2003

27 S3-27PAT301, Section 3, October 2003 FILE IMPORT OPTIONS

28 S3-28PAT301, Section 3, October 2003 FILE IMPORT OPTIONS (Cont.) Geometry kernel type CAD part Standard format

29 S3-29PAT301, Section 3, October 2003 EXAMPLE: UNIGRAPHICS CAD MODEL IMPORT n Select Import... from the File menu n Set Unigraphics as the Source n Select desired UG part file n Optional filtering of entities is available based on entity type (e.g. Sheet Body), CAD layer and if sewing is to be done

30 S3-30PAT301, Section 3, October 2003 is used to filter the Unigraphics entities being imported n Filter Options include u Entity Types l Wire Body – curve l Sheet Body – surface l Solid Body – solid u Entity Layers u Trimmed Surface Type u Sew Sheet Bodies EXAMPLE: UNIGRAPHICS CAD MODEL IMPORT (Cont.) UNIGRAPHICS OPTIONS

31 S3-31PAT301, Section 3, October 2003 n Two buttons u Pro/ENGINEER CAD model import u MSC.GS-Mesher for meshing solids n Import to Parasolid – create parasolid or not n Part – individual part; need license n Assembly – set of parts; need license n Primitive Geometry – created from CAD import into MSC.Patran; no license needed EXAMPLE: PROENGINEER CAD MODEL IMPORT

32 S3-32PAT301, Section 3, October 2003 EXAMPLE: PROENGINEER CAD MODEL IMPORT (Cont.) n Use MSC.GS-Mesher to mesh Pro/ENGINEER solid in Pro/ENGINEER environment u Pro/ENGINEER is executed u Geometry is accessed in Pro/ENGINEER through API u Meshing is done using MSC.GS-Mesher u Resulting mesh is read into MSC.Patran n Must have Pro/ENGINEER and GS-Mesher installed, and have the MSC.Nastran preference in MSC.Patran

33 S3-33PAT301, Section 3, October 2003 EXPRESS NEUTRAL FILE n Express Neutral files are intermediate files that are created during a specific CAD model access, i.e. UG Express Translation, CATIA Direct n Express Neutral files are portable when created as text files n Express Options provide capabilities such as filtering entities, group creation, model preview

34 S3-34PAT301, Section 3, October 2003 IGES FILE n IGES format n Supports u Point u All curve types u All surface types, except MSC.Patran composite u B-rep solid

35 S3-35PAT301, Section 3, October 2003 MSC.PATRAN DATABASE ACCESS n MSC.PATRAN database content can be transferred between different databases n Import option allows the specification of entity type, ID offset, name prefix, and conflict resolution tools n Equivalence Option allows common entities in the databases to be equivalenced n Preview option provides access to summary information

36 S3-36PAT301, Section 3, October 2003 MSC.PATRAN DATABASE ACCESS (Cont.) n MSC.Patran databases can be accessed by selecting MSC.PATRAN DB as the source

37 S3-37PAT301, Section 3, October 2003 MSC.PATRAN DATABASE ACCESS (Cont.) n Importing options (MSC.Patran DB options) controls u Which entities to import u Specification of entity ID offset. u Specification of unique names, e.g. prefix for group names

38 S3-38PAT301, Section 3, October 2003 MSC.PATRAN DATABASE ACCESS (Cont.) n Merged finite element and geometry models may be equivalenced-Equivalence Nodes/Geometry n Options on how MSC.PATRAN will deal with Discrete FEM Fields (discussed later) on import

39 S3-39PAT301, Section 3, October 2003 FILE EXPORT OPTIONS

40 S3-40PAT301, Section 3, October 2003 FILE TYPES EXPORTED n IGES file u Points, all curve types, and all surface types, e.g. trimmed parametric surface u Geometric solids u FEM nodes and elements u Coordinate frames u No results n MSC.Patran neutral file u FEM consisting of nodes, elements, material properties, u Element properties, coordinate frames, etc. u No results u ONLY simple geometry types, e.g. parametric bicubic

41 S3-41PAT301, Section 3, October 2003 FILE TYPES EXPORTED (Cont.) n Parasolid xmt file u Specific types of parasolid geometry l Curves l Surfaces l Solids u Can specify the parasolid version n STEP file u AP203 – geometry only u AP209 – geometry, mesh, analysis, and/or results

42 S3-42PAT301, Section 3, October 2003

43 S3-43PAT301, Section 3, October 2003 MSC.PATRAN GEOMETRY APPLICATION

44 S3-44PAT301, Section 3, October 2003

45 S3-45PAT301, Section 3, October 2003 n Geometry can be constructed in MSC.PATRAN by u Editing imported CAD geometry (Edit/Surface/Sew) u Building with respect to existing geometry (Create/Solid/Extrude) u Creating copies of existing geometry (Transform) GEOMETRY CONSTRUCTION Extracting a curve Gliding a surface to create a solid Rotating Mirroring

46 S3-46PAT301, Section 3, October 2003 GEOMETRY ENGINES IN MSC.PATRAN n There are two approaches that can be used in MSC.Patran to create and edit geometry. They are standard and parasolid n Standard tools u Use Patran unique code/libraries u Has long history of being used n Parasolid tools u Use parasolid libraries in Patran u Need Patran parasolid tool license u Pages with parasolid tool indicated mean that the approach described uses the parasolid libraries

47 S3-47PAT301, Section 3, October 2003 ACCESSING GEOMETRY FORMS n Create or edit geometry under the Geometry icon in the MSC.Patran main menu.

48 S3-48PAT301, Section 3, October 2003 GEOMETRY FORM ANATOMY n The strategy behind working with the geometry form: u Set an objective, such as creating a point u Provide the details associated with creating the entity using the specified method... Action Object Method... Surface XYZ Face Revolve Curve XYZ Trimmed Revolve Point Manifold Chain Revolve XYZ Interpolate Extract Project CreateDelete PointCurveSurfaceSolid...

49 S3-49PAT301, Section 3, October 2003 SELECT MENU n Provides an entity selection filter n Cursor placed in list box displays select menu n Select menu icons filter entity selection - only entities selected are of type of chosen filter icon n Selections available depend on what is being done, e.g. create a point using XYZ n option allows screen picking of only the entities on front of model Pick only geometry point or finite element node Pick only geometry point Pick only finite element node

50 S3-50PAT301, Section 3, October 2003

51 S3-51PAT301, Section 3, October 2003 GEOMETRIC ENTITIES - POINT

52 S3-52PAT301, Section 3, October 2003

53 S3-53PAT301, Section 3, October 2003 CREATE/POINT/XYZ n Create points at X, Y, Z location n Locations where points are to be created may be specified by either: u (X,Y,Z) coordinates (list of coordinates), e.g. [ ] [0 0 70] u Picking a choice from the select menu and following the menu prompts, e.g. Node u 2 1 u 3

54 S3-54PAT301, Section 3, October 2003 POINT CREATE Create a point at the center of an arc Create a point at parametric location x 1 x x Create a point at the intersection of a curve and surface Create points non-uniformly on a curve x x a 1 3 x a

55 S3-55PAT301, Section 3, October 2003 SHOW/POINT/DISTANCE n Provide distance between a point and other entity (i.e. point, surface).

56 S3-56PAT301, Section 3, October 2003 GEOMETRY TRANSFORM* MethodComment TranslateTranslate entity through a specified vector RotateRotate entity about a defined axis through a given angle ScaleUse a multiplicative factor applied to individual coordinate MirrorCreate a mirror image of entity across a defined plane McoordTransform entity in one coordinate frame into another with same relative position PivotTransform entity within a plane defined by a pivot and two points PositionEntity transformed to a set of destination-position-points will maintain its relative position to a set of original-position-points VsumVector sum of the coordinate locations of two sets of existing entities to create a new entity MscaleExisting entity is simultaneously moved, scaled, rotated and/or warped to a new position using a rotation matrix * Transform operations for geometry types point, curve, surface and solid

57 S3-57PAT301, Section 3, October 2003 GEOMETRIC ENTITIES - CURVE

58 S3-58PAT301, Section 3, October 2003

59 S3-59PAT301, Section 3, October 2003 n Patran has the capability of creating various types of geometry, for example: u Implicit form, i.e. conic, elliptical u Explicit form, i.e. parametric cubic, Beizier, NURBS n Patran uses Neutral File convention to indicate that cubic parametric geometry (parametric cubic geometry) will be created, e.g. with a similar equation for Y and Z n Neutral File convention can be selected under Geometry Representation in Preferences/Geometry n Some geometry is created using only Neutral File convention, e.g. Create/Curve/Point GEOMETRY TYPES

60 S3-60PAT301, Section 3, October 2003 CASE STUDY: PARAMETRIC CURVES n Create three points. u Select the Geometry Applications button. u Set Action/Object/Method to Create/Point/XYZ. u Apply. u Create two more points using the following coordinates l [2 2 0], [ ].

61 S3-61PAT301, Section 3, October 2003 n Create a parametric curve with u=0.5 for the middle point. u Set Action/Object/Method to Create/Curve/Point. u Select 3 Point for Option. u Set the u value of Middle point to 0.5. u Select Point 1 for Starting Point List. u Select Point 3 for Middle Point List. u Select Point 2 for Ending Point List. u Apply. CASE STUDY: PARAMETRIC CURVES

62 S3-62PAT301, Section 3, October 2003 n Create a parametric curve with u=0.75 for the middle point. u Set Action/Object/Method to Create/Curve/Point. u Set the u Value of Middle Point to u Apply. CASE STUDY: PARAMETRIC CURVES

63 S3-63PAT301, Section 3, October 2003 CURVE CONSTRUCTION Must use the select menu for picking the curve and point

64 S3-64PAT301, Section 3, October 2003 CREATE/CURVE/MANIFOLD n Manifold refers to creating new geometry on (coincident with) existing geometry, e.g. curve on surface from one point to another point Before After Surface

65 S3-65PAT301, Section 3, October 2003 CREATE/CURVE/CHAIN n Create a composite curve from two or more existing curves or edges n It retains exactly all the information of the constituent curves Individual curves Chain curve used for trimmed surface Individual curvesChain (composite) curve X Y Z 11 X Y Z

66 S3-66PAT301, Section 3, October 2003 AUTO CHAINING FEATURE n Provide user with interactive, more controllable way to chain curves n Chaining starts by selecting a starting curve n Decisions on how to proceed with the chaining process are made through the toggles and buttons on the form, i.e. Next (find another possible path for chain), or OK (proceed along the current path) n Accessible from Create/Curve/Chain or Create/Surface/Trimmed forms

67 S3-67PAT301, Section 3, October 2003 EDIT/CURVE/BREAK n Creates two curves by breaking an original curve or edge at a parametric position along the curve between 0.0 and 1.0 Trimmed surface 3 Point 21 is created at parametric 0.4 position along u (or c1) direction 3 3 Edge

68 S3-68PAT301, Section 3, October 2003 CURVE EDIT Must use select menu for picking the curve and point PATRAN extracts points from all curves and creates one spline curve from them The parametric coordinate for each curve is represented by a line with a 1 Simple mathematical representation of original curve using a set of parametric cubic curves complex mathematical representation Single curve;

69 S3-69PAT301, Section 3, October 2003 CURVE SHOW Curve ID 1 Start Point 1 End Point 2 Length Type ParametricCubic First Curve ID 1 Secon Curve ID 2 Angle 45. Minimum Distance 0. Minimum Location1 [ ] Minimum Location2 1on> Curve ID 1 Start Point 1 End Point 2 Length Center [ ] Radius 1. Type Arc Curve ID 1 Start Point 1 End Point 2 Length 1.4 Type ParametricCubic ParametricCubic ParametricCubic

70 S3-70PAT301, Section 3, October 2003 EXERCISE Perform Workshop 3 Frame Model Creation Using Curves, and Analysis in your exercise workbook

71 S3-71PAT301, Section 3, October 2003 GEOMETRIC ENTITIES - SURFACE

72 S3-72PAT301, Section 3, October 2003

73 S3-73PAT301, Section 3, October 2003 PARAMETRIC SURFACE CREATE Curves must be non-intersecting(non-touching)Curves must be end-to-end Must use the select menu for picking both surface and point; fillet is parametric bicubic.

74 S3-74PAT301, Section 3, October 2003 TRIMMED SURFACE CONSTRUCTION Three options for creating a trimmed surface in MSC.PATRAN Planar Trimmed 2-D Surface Surface Trimmed 3-D Surface Composite Trimmed

75 S3-75PAT301, Section 3, October 2003 TRIMMED SURFACE CONSTRUCTION (Cont.) n When creating a trimmed surface, one must define its edges u Chain together curves to form closed loops l One outer loop to define the outer boundary l As many inner loops as necessary (if any) to define holes/cutouts n Define curvature of surface u Planar trimmed for a flat surface u Surface trimmed requires a parent surface (must be parametric) to define the curvature of the new surface; only one surface permitted n For composite trimmed creation must specify all surfaces to be combined

76 S3-76PAT301, Section 3, October 2003 CREATE TRIMMED SURFACE EXAMPLE n The Outer Loop List can have only one curve ID, e.g. Curve 14; the curve must close on itself n There can be as many inner loops as needed, e.g. Curve 13, 15, 16; only one curve per inner loop n Single surface ID in Surface List, e.g. Surface 1. It is the parent surface and must be parametric (green) Curves and Parent SurfaceResulting Trimmed Surface Parent surface

77 S3-77PAT301, Section 3, October 2003 CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES n Import the following Geometry. u File/Import u Set Object/Source to Model/IGES. u Select the file called 2trim_surfs.igs. u Apply. u When the IGES Import Summary appears, Click OK.

78 S3-78PAT301, Section 3, October 2003 n Your model should now appear as follows CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES Surface 2 Surface 1 Curve 1

79 S3-79PAT301, Section 3, October 2003 n Change the view to Iso1 View using the following icon. n Turn on the display lines using the following icon. n Display the curve and surface labels. CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES

80 S3-80PAT301, Section 3, October 2003 n Create trimmed surfaces, both with the same outer loop but different parent surfaces. u Select the Geometry Applications button. u Set Action/Object/Method to Create/Surface/Trimmed. u Select Curve 1 for Outer Loop List. u Select Surface 1 for Surface List. u Do not delete original curve, but delete the original surface. u Repeat for Surface 2, again using Curve 1. CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES

81 S3-81PAT301, Section 3, October 2003 n The two trimmed surfaces should now appear as follows: CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES

82 S3-82PAT301, Section 3, October 2003 n Shade the two trimmed surfaces by clicking on the following icon. CASE STUDY: TRIMMED SURFACES WITH DIFFERENT PARENT SURFACES

83 S3-83PAT301, Section 3, October 2003 COMPOSITE SURFACE n One composite surface created from a set surfaces n Meshing will ignore the original interior vertices and edges Original Surfaces Composite Surface with Mesh

84 S3-84PAT301, Section 3, October 2003 CREATE COMPOSITE SURFACE n A composite surface is created from multiple surfaces u Useful for coarse meshing a region of numerous surfaces u Can use parametric composite surfaces to create parametric solids, which can be hex meshed n User defined boundary features such as vertices, inner loops, and curves at perimeter gaps (Preview Boundary) n Vertices u Use All Edge Vertices – all vertices at outer perimeter of surfaces in Surface List u Vertex List – if only use some vertices, e.g. create parametric surface n Inner Loop Option – All, None, Select (some)

85 S3-85PAT301, Section 3, October 2003 CREATE COMPOSITE SURFACE (Cont.) n Preview Boundary u Can use Preview Boundary to see if continuous boundary (white) exists around perimeter of surfaces; if not, can add (create) curves or remove curves or edges from list on the fly to define desired outer perimeter u Select menu can only be used to pick curves or edges, or 2 points to define a curve Curve or Edge

86 S3-86PAT301, Section 3, October 2003 CREATE COMPOSITE SURFACE (Cont.) n Options can be used to assist with surface creation u Perimeter (boundary) gaps less than Cleanup Tol. will be closed u Gap Distance is similar to Cleanup Tol., except it refers to gaps between internal edges of surfaces

87 S3-87PAT301, Section 3, October 2003 COMPOSITE SURFACE EXAMPLE Four Non-congruent Surfaces Trimmed Composite Surface Parametric Composite Surface n Create composite surfaces u Surface 1:4 u Surface type l Trimmed: use All Edge Vertices l Simple: use four corner vertices u Options l Clean up Tol.=0.071 l Gap Distance=0.071 n Continued u Preview Boundary l Add (Two Points icon) n Select point pairs at all 4 outside perimeter gaps l Remove (Curve or Edge icon) n Select all 8 interior edges

88 S3-88PAT301, Section 3, October 2003 CREATE MIDSURFACE FROM SOLID n Create surface midway through thickness of portions of a parasolid solid n Use for shell meshing a solid n Two modes for creation u Automatic l Specify the thickness of the regions for which surfaces are to be created u Manual l Two faces of a given solid between which a mid-surface is to be created must be specified n Solid Face List – a face n Offset Solid Face List – opposing face Manual Automatic

89 S3-89PAT301, Section 3, October 2003 SURFACE EDIT Set of parametric bicubic surfaces Can use simultaneously with all surfaces Surfaces have continuous slope

90 S3-90PAT301, Section 3, October 2003 SURFACE EDIT (Cont.) Point 35 Parametric Surface 6 Trimmed surface with hole Trimmed Surface 8 with hole Parametric surface without hole Trimmed Surface 4 Remove vertex Parametric surface Point 44 Parametric Surface 2 New vertex Trimmed surface

91 S3-91PAT301, Section 3, October 2003 EDGE MATCH SURFACE n Mesh continuity requires adjacent surfaces be congruent n Two non-congruent surfaces may be matched along adjacent edges n Congruency can also be enforced using Edit/Surface/Break n Edit/Surface/Sew includes Edge Match and Edit/Point/Equivalence All surfaces have four edges Add vertex to surface 1 at point 5

92 S3-92PAT301, Section 3, October 2003 SURFACE TRANSFORM MIRROR OPTION n First, select the appropriate select menu icon – coordinate direction 1 n Second, click on local Coordinate System 1 in the viewport to specify the mirror plane to be coincident with the local YZ-Plane n Third, select the geometry to be mirrored

93 S3-93PAT301, Section 3, October 2003 VERIFY SURFACE BOUNDARY n Plots free and non-manifold surface edges in model u Free edge: no congruent adjacent surface edge (magenta circle) u Non-manifold edge: shared by more than two surface edges (blue dot) Free edge Non-manifold edge

94 S3-94PAT301, Section 3, October 2003 CASE STUDY: VERIFY SURFACE BOUNDARIES n Import geometry. u File/Import/IGES. u Select radial_surfs.igs from the file menu. u Your model should now appear as follows.

95 S3-95PAT301, Section 3, October 2003 n Change the view to Iso 4 View by clicking on the following icon. CASE STUDY: VERIFY SURFACE BOUNDARIES

96 S3-96PAT301, Section 3, October 2003 n Verify if the surfaces are congruent. u Click on the Geometry Applications button. u Set Action/Object/Method to Verify/Surface/Boundary. u Select Surface 1:16 for Surface List. u Apply. CASE STUDY: VERIFY SURFACE BOUNDARIES

97 S3-97PAT301, Section 3, October 2003 n See magenta colored markers on all free edges. n All free edges are on perimeter, except for 2 that are interior. CASE STUDY: VERIFY SURFACE BOUNDARIES Non-Manifold Edges External Free Edge Internal Free Edges

98 S3-98PAT301, Section 3, October 2003 n Change the view to see better. u Click on the Mouse rotate XY icon. u Rotate by holding down the middle mouse key until desired view is attained. CASE STUDY: VERIFY SURFACE BOUNDARIES Free Edges Zoom In View

99 S3-99PAT301, Section 3, October 2003 n IsoMesh the surfaces. u Select the Finite Element Applications button. u Set Action/Object/Type to Create/Mesh/Surface. u Select the IsoMesh Mesher. u Select all surfaces, except Surface 16 (not attached to the model). u Enter for Global Edge Length. u Apply. CASE STUDY: VERIFY SURFACE BOUNDARIES

100 S3-100PAT301, Section 3, October 2003 n IsoMesh the last surface of the model. u For the last unmeshed surface enter 0.5 for the Global Edge Length. u Select Surface 16 in the Surface List. u Apply. n Notice that you can create non-matching mesh where the geometry is not congruent. CASE STUDY: VERIFY SURFACE BOUNDARIES

101 S3-101PAT301, Section 3, October 2003 EXERCISES Perform Workshop 4 Midsurface Extraction Example in your exercise workbook.

102 S3-102PAT301, Section 3, October 2003

103 S3-103PAT301, Section 3, October 2003 GEOMETRIC ENTITIES - SOLID

104 S3-104PAT301, Section 3, October 2003

105 S3-105PAT301, Section 3, October 2003 SOLID CONSTRUCTION Use nonintersecting parametric surfaces to create parametric solid Use set of any type of surfaces to create an MSC.Patran native B-rep solid Use 5 parametric surfaces to create 6 faced parametric solid Glide a parametric surface along a curve to create a parametric solid

106 S3-106PAT301, Section 3, October 2003 CREATE PARASOLID B-REP OR PARAMETRIC SOLID BY EXTRUDING SURFACE n Extrude a surface (or solid face) to create a solid n Select to create either a TetMeshable (Parasolid B-rep) or IsoMeshable (parametric) solid n If select TetMeshable the surface can be parametric or trimmed n If select IsoMeshable the surface must be parametric n Parasolid tool IsoMeshable TetMeshable

107 S3-107PAT301, Section 3, October 2003 CREATE PARASOLID B-REP OR PARAMETRIC SOLID BY REVOLVING SURFACE n Revolve a surface (or solid face) to create a solid n Similar to extrude – select either TetMeshable or IsoMeshable n Same restrictions on surface types as for extrude n Parasolid tool IsoMeshable TetMeshable

108 S3-108PAT301, Section 3, October 2003 CREATE PRIMITIVE SOLIDS n Create Parasolid B-rep solids of various basic shapes n Shapes are Block, Cylinder, Cone, Sphere, and Torus n Parasolid Solid can be created quickly using this form, or it can be created manually using Geometry/Create/ Solid/B-rep (get Patran native B-rep Solid), then refitting to create a parasolid B-rep solid n Primitive solid can only be meshed with the TetMesher n Parasolid tool

109 S3-109PAT301, Section 3, October 2003 SOLID EDIT MethodComment BreakBreak a solid into multiple solids using a selected option such as a surface, parametric location, etc. BlendCreate a set of cubic parametric solids from a set of parametric solids such that the first derivative of shape is continuous across interfaces DisassembleDisassemble a B-rep solid into a set of surfaces (may be parametric or trimmed) RefitReplace an existing complex shaped parametric solid with a set of simple cubic parametric solids. The extent to which the new solids match the original solid depends on how many solids are created. Also, can create a parasolid solid. ReverseReverse the parametric directions associated with the solid BooleanAdd, subtract, or intersect parasolid solids. Parasolid tool Edge BlendCreate fillets or chamfers. Parasolid tool ImprintBreak parasolid faces at edges of other solids. Parasolid tool ShellRemove space from parasolid solid to create walls. Parasolid tool

110 S3-110PAT301, Section 3, October 2003 EDIT SOLID BY REFIT n Edit solid three ways u Option To Tri Cubic Net causes a set of cubic parametric solids to be created to represent the original solid l Refit parameters u Density, v Density, w Density* u Option To TriParametric is similar to To Tri CubicNet except a tolerance is used instead of u Density, etc. u Option To Parasolid causes a parasolid solid to be created from the original solid u Parasolid tool * Density is the number of solids that will be created in the u, v, w direction.

111 S3-111PAT301, Section 3, October 2003 SOLID GEOMETRY BOOLEAN n Solids to be combined can be Patran native B-rep, parasolid B-rep solid, and/or parametric n Solids could have been created in Patran or imported n Boolean operations are Add, Subtract, and Intersect n Any combination of solid types results in creating a parasolid B-rep solid n Parasolid tool Add B-rep Parametric B-rep (from Add) 1 2 3

112 S3-112PAT301, Section 3, October 2003 n Create a 1x1x1 blue parametric solid u Click on the Geometry Applications button. u Set Action/Object/Method to Create/Solid/XYZ. u Apply. u Change the view by using the Iso 1 View icon. CASE STUDY: ADDING SOLIDS

113 S3-113PAT301, Section 3, October 2003 n Create a point in the center of a solid face. u Click on the Geometry Applications button. u Set Action/Object/Method to Create/Point/Extract. u Select the Single Point on Surface icon u Select Solid 1.2 for Surface List. u Apply. n Repeat for Parallel Face u Select Solid 1.1 u Apply. CASE STUDY: ADDING SOLIDS Solid 1.2 Solid 1.1

114 S3-114PAT301, Section 3, October 2003 n Display entity labels u Click on the following icon. n Increase the size of the point markers u Click on Display. u Select Geometry… u Increase Point Size using the slide bar. u Apply. CASE STUDY: ADDING SOLIDS

115 S3-115PAT301, Section 3, October 2003 n Create spherical shaped parasolid solid with the center at the center of a solid face. u Set Action/Object/Method to Create/Solid/Primitive. u Select Sphere icon in Form. u Set the radius in Radius List to 0.5. u Select Point 9 for Center Point List. u Click on the Axis List box. l Use the Tip and base points icon in the select menu. l Select the Point icon in the next level of the select menu. l Select the point at the center of two solid faces, Point 9, 10. u Apply. CASE STUDY: ADDING SOLIDS Tip and base icon

116 S3-116PAT301, Section 3, October 2003 CASE STUDY: ADDING SOLIDS n These are the two solids.

117 S3-117PAT301, Section 3, October 2003 n Add the parametric and parasolid solids u Set Action/Object/Method to Edit/Solid/Boolean. u Select the first icon (Add). u Select Solid 1 2 for Solid List. u Apply. CASE STUDY: ADDING SOLIDS

118 S3-118PAT301, Section 3, October 2003 n Shade the newly created parasolid solid. u Click on the following icon. u Turn off the labels. CASE STUDY: ADDING SOLIDS

119 S3-119PAT301, Section 3, October 2003 EXERCISES Perform Workshop 5 Frame Surfaces Creation in your exercise workbook.

120 S3-120PAT301, Section 3, October 2003

121 S3-121PAT301, Section 3, October 2003 GEOMETRIC ENTITIES – COORDINATE FRAME

122 S3-122PAT301, Section 3, October 2003

123 S3-123PAT301, Section 3, October 2003 DEFINING COORDINATE FRAMES n The 3 axes, for each coordinate system, are generically referred to as the 1, 2, 3 axes with the above definitions Rectangular X Y Z Cylindrical R Z Spherical R Z X Y A B C P(X,Y,Z) Z Y X Z R A B C P(R,,Z) R Z R A B C P(R,, ) R

124 S3-124PAT301, Section 3, October 2003 COORDINATE CREATE MethodComment 3PointCreate a coordinate frame by defining an origin, a point along the axis 3 and a point in the 1-3 plane AxisA point on axis i and another on axis j EulerThree consecutive rotations about user defined axes NormalSpecify an origin and a surface

125 S3-125PAT301, Section 3, October 2003 CREATE COORDINATE ALIGNED WITH SURFACE NORMAL n Creates a rectangular coordinate system n Origin at a point on a surface or solid face n Coordinate frame axis 3 aligned normal to the surface or face n Coordinate frame axis 1 aligned with either parametric direction Surface 1 7 X Y Z 5 X Y Z Point 5 Coordinate Frame 7 1 2

126 S3-126PAT301, Section 3, October 2003

Еще похожие презентации в нашем архиве:

Готово:

WS10-1 WORKSHOP 10 Tetmeshing Anchor Geometry and Verifying Mesh Quality PAT301, Workshop 10, October 2003.

WS10-1 WORKSHOP 10 Tetmeshing Anchor Geometry and Verifying Mesh Quality PAT301, Workshop 10, October 2003.

© 2018 MyShared Inc.

All rights reserved.