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Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Section 7 Mesh Control.

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Presentation on theme: "Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Section 7 Mesh Control."— Presentation transcript:

1 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Section 7 Mesh Control

2 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information The automated meshing process in SimLab can generate mesh that is suitable for the following Analysis Types. Analysis type Durability / Stress analysis NVH analysis Acoustic analysis Drop test Fluid analysis For each of the above analysis types, the desired mesh density and the quality of the mesh differs. In SimLab, the output mesh is controlled by specifying Mesh Controls. Mesh controls are applied directly to the CAD models. Mesh Control Overview

3 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Mesh controls are classified under the following types, Global mesh controls It is assigned to bodies or assemblies and all underlying geometry entities, (faces and edges), will inherit this global mesh control. It is mandatory to specify the global mesh control. Local mesh controls Local mesh controls are used to control the mesh in a particular region. It over rides the global mesh controls. It is assigned to bodies, faces and edges. Mesh Control - Classifications

4 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Global mesh controls are defined while surface meshing or volume meshing. Surface meshing Surface meshing is used to generate a surface mesh body from a CAD body. Surface elements supported are Tri3, Tri, Quad4, Bar2 and Bar3. Volume meshing Volume meshing is used to generate a volume mesh body from a CAD body or a surface mesh body. Volume elements supported are Tet4, Tet10, Wedge6 and Hex8. Global Mesh Controls

5 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Global Mesh Controls Surface meshing

6 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Global Mesh Controls Volume meshing Input

7 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Global Mesh Controls Volume meshing Output

8 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Mesh size on geometry Body Faces Edges Regions (with Break option) Mesh size on features Fillets Cylinders Washer Circle Imprint Valve Seat Pocket Iso-Line Seeding Edges Hard points Faces Edges Preserve Entities Face Edges Face shape Edge Mesh Symmetry Mesh Mesh Patterns Isomesh Free Mesh Union Jack The local mesh controls available are Local Mesh Controls

9 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Following are the local mesh control parameters, 1.Face Mesh Control 2.Edge Mesh Control 3.Body Mesh Control 4.Fillet Mesh Control 5.Cylinder Mesh Control 6.Washer Mesh Control 7.Circle Imprint Mesh Control 8.Region Mesh Control 9.Valve Seat Pocket Mesh Control 10.Iso-Line Mesh Control 11.Volume Layer Mesh Control Local Mesh Controls

10 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Face Mesh Control is used to control the mesh on the selected local faces. A uniform mesh is generated on the face that has the face mesh control specified. InputOutput Mesh 1. Face Mesh Control

11 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Edge seeds are applied either by specifying average element size or number of elements. Bias Seeding is used to seed an edge such that a constant ratio is maintained between adjacent bar elements. Edge Length will be in the following series: Lmin, Lmin * r, Lmin * r * r,... where, Lmin is the minimum edge length and r is the ratio. Input Output Mesh 2. Edge Mesh Control

12 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Body Mesh Control is used to control the mesh on selected local bodies. All entities (faces and edges) present in the body, except the entities with other local mesh controls, will inherit this mesh control. Input Output Mesh 3. Body Mesh Control

13 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Fillet Mesh Control is used to control the mesh over fillets along the length and the curve direction. InputOutput Mesh 4. Fillet Mesh Control

14 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Cylinder Mesh Control is used to control the mesh both axially and radially on the selected cylindrical faces. Input Output Mesh 5. Cylinder Mesh Control

15 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Washer mesh control is used to create rings around a circle. The circle has to be inside one face. 6. Washer Mesh Control Input Output Mesh

16 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Creates circular edge on a face with the specified radius and the number of seeds. 7. Circle Imprint Mesh Control Input Output Mesh

17 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Region mesh control applies local refinement within the defined shape (Cuboid / Cylinder) of region. The selected entities (faces/bodies) that lies inside the region will be assigned the specified size. Entities which are partially inside the region will be graded according to region of overlap. Also the region can break the face/body along the boundary of the chosen shape (Cuboid / Cylinder / Plane). The Plane option is used to Break the body or face. 8. Region Mesh Control

18 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Region Mesh Control -Cylinder – Local Size – Without Break Input 8. Region Mesh Control

19 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Region Mesh Control -Cylinder – Local Size – Without Break Output 8. Region Mesh Control

20 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Valve Seat Mesh control is used to control the mesh in the valve seat pocket region. This controls the mesh on the cylinder and disc faces in the axial and radial direction and also preserves the chamfer faces if needed. 9. Valve Seat Mesh Control

21 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Input 9. Valve Seat Mesh Control Output Valve Seat Mesh control without Preserve Chamfer

22 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information 9. Valve Seat Mesh Control Valve Seat Mesh control with Preserve Chamfer InputOutput

23 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Iso-Line Mesh control is used to control the mesh on cylinders and partial cylinders. It strictly maintains the axial mesh size and the angle. This separates iso-line mesh control from fillet and cylinder mesh controls. Reference point and direction is used to define the start point and the direction of the isomesh. Merge option is used to merge the selected faces. Reference point is also used to generate a mesh such that a radial shift of the iso- mesh is required. 10. Iso Line Mesh Control

24 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Input 10. Iso Line Mesh Control Output

25 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Volume Layer Mesh control is used to generate layers of Tet elements along thin regions. The number of layers can also be specified in terms of the thickness of each layers. This option is useful when the number of layers have to change with the thickness for a body that has regions of variable thickness. 11. Volume Layer Mesh Control

26 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Input 11. Volume Layer Mesh Control

27 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Output 11. Volume Layer Mesh Control

28 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Hard points are used to create nodes at the specified point location on a face or an edge during meshing. Hard Points can be defined by selecting a point on the face/edges. In case of meshed body we can select nodes as hard point. Input Output Mesh Hard Points – Mesh Control

29 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information The automated meshing process can collapse sliver faces. The mesher will automatically decide which one to preserve and which one to collapse. Using Preserve Entities mesh control, the user can control the features to be preserved while meshing. There are five types of preserve entities. Face Shape Face Edges Edge Symmetry Mesh Mesh Preserve Entities

30 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Face Shape This option is used to retain the planarity of the face after meshing. The nodes in the face will not get moved out of the face. Face Edges This option is used to retain all the edges of the face after meshing. This means that tiny edges on the faces will be preserved and the face will not get collapsed. Edge This option is used when only few edges of a face, are to be preserved when meshing. Preserve Entities

31 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Preserve Entities Symmetry Mesh This option is used to get identical mesh between the master face and symmetry face. If there are any discontinuous edges, then we need to pick three nodes/vertices in an order for both master and symmetry face. Mesh This option is used to maintain the existing mesh in the face during meshing.

32 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Mesh Pattern The manner in which elements are arranged in a face is known as mesh pattern. The three types of mesh pattern available are, Iso-Mesh This create elements that have 2 edges almost 90 degrees and the diagonals are inclined in the same direction. This iso-mesh pattern can be created on a four sided surfaces. UnionJack This create elements that have two edges almost 90 degrees and the diagonals are inclined in the opposite direction. Free Mesh This creates a mesh wherein, the mesh does not follow any pattern. Mesh Patterns

33 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Mesh Patterns

34 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Local mesh controls Select “Mesh Control” in meshing tool bar. This opens the “Mesh Control Parameters” dialog box. Select entities and enter values for the mesh control. Created “Mesh controls” are listed in the “Assembly Model” tree window under “Process Control” tab. Local Mesh Controls

35 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Whenever, a local mesh control is created, it is listed in the tree view. By double clicking the mesh control, the “Mesh Control Parameters” dialog box will open with all values set. These vales can be modified and saved. Select a face, right click and select “Local Meshing Parameters”. This opens the mesh control assigned to the selected face. This will work for bodies, faces and edges. Modifying Local Mesh Control

36 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Exporting a mesh control The Mesh control created can be saved in an external file, called "Mesh Specification" and the saved file can be imported back into SimLab. This is very useful when meshing models of similar types when the mesh control created for one can be reused for the others. Mesh Control Specification

37 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Exporting a mesh control This has 4 options, Template Mesh control parameters will be stored along with the geometry type associated with it, (like FACE, EDGE) Useful for assigning mesh control for models of the same type Body Mesh control parameters will be stored along with the entity id. Useful for re-meshing the same model several times or the same model with small changes in the CAD file. Mesh Control Specification

38 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Exporting a mesh control Color Mesh control parameters will be stored along with the color associated with it. Useful for assigning mesh control for models based on color. Groups Mesh control parameters will be stored along with the group name associated with it. Useful for assigning mesh control for models based on groups. Mesh Control Specification

39 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information Importing a mesh control Select a body to which the mesh control is to be assigned. Open the “Mesh Control Parameters” dialog box and select “Import File” Choose the mesh control file (with extension.xml). This will load all the mesh controls defined in the mesh control file. Go to the “Mesh Control” dialog box to see the imported mesh controls in the tree view. If template mesh spec is used, select bodies, faces, edges or features and assign it to the mesh control. Mesh Control Specification

40 Copyright © 2010 Altair Engineering, Inc. All rights reserved.Altair Proprietary and Confidential Information It is common to find several cylinders with the same axis but separated by discs, cones or circular edges. It is sufficient to assign mesh control to one or part of a circular edge and all the edges will pick up the mesh seed. It is sufficient if the axial mesh size if assigned to one cylinder and all cylinders will pick it up. This transmission of the mesh size will stop if the circular disk separating the cylinders is too thick. Automation


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