Grid Generator in ANSYSGrid Generator in ANSYS

58:110 Computer-Aided Engineering Spring 2005

Department of Mechanical and industrial engineering

February 2005

Topics

Running ANSYS Geometry Model Prepare before Meshing Meshing methods

Free/Automatic meshing Mapped meshing Sweep meshing

Checking

Running ANSYS

To run ANSYS:

Login any ICAEN PC with WIN XP

Start -> All Programs

-> Engineering Software

-> ANSYS 8.1

Geometry Model

Import form Pro/E:

File ->

Import -> IGES

Geometry Model

Geometry Model

Simple Geometry Can be generated in ANSYS too. Goto ANSYS Main Menu

Preprocessor -> Modeling->Create ->Operate ->Modify/Move ->Copy …….

Prepare Before Meshing

Check Geometry

Check geometry carefully. Make sure there is no gap, overlap, broken line/area/volume.

Set Element Type

Goto ANSYS Main Menu

Preprocessor -> Element Type -> Add/Edit/Delete

Select the appropriate element type

Meshing methods - Free Meshing Free meshing has no limited by shape and pattern. Only available for 2D quadrilateral/triangular element shapes and 3D tetrahedral

elements It is easy but for complex geometries can often lead to distorted elements that undermine

accuracy. Meshing Commands

Goto ANSYS Main Menu

Preprocessor -> Meshing ->Mesh Attributes

-> Mesh tool

-> Size Cntrls

………………

Free Meshing

MeshTool -> Check SmartSize, select 6 (1 to 10: From Fine to Coarse) -> Mesh: Volumes Shape: Tet and then Mesh

Want to refine mesh (supposed at the bottom): -> Refine at, Elements and then Refine Box select the elements around the bottom area and select the refine level (1 to 5: min to max) 3 Circle select the elements around the hole and select the refine level (1 to 5: min to max) 2 Then apply.

Free Meshing

Original Mesh After refinement

Free Meshing

Uniform mesh in one volume

(Size control)MeshTool

-> Uncheck SmartSize

-> Size controls:

Global -> Set

Global Element Sizes

->Size Element Edge Size

5

and then Mesh

Mapped Meshing

Mapped meshes are easier to control and offering more accurate User should specify the size and shape of the meshes in local regions Before use the Mapped meshing, the regions should satisfy:

2D - each aea must be 4 / 3 sided, that is the area should be made up of 3 or 4 lines/curves

3D – each volume must have 6 faces

Mapped Meshing

Procedure

1. Partition the non 6-faced volumes

Preprocessor->Modeling->Operate->Divide: Volu by WrkPlane

2. Mapped Meshing

MeshTool

-> Uncheck SmartSize

-> Size controls:

Global -> Set:Global Element Sizes

->Size Element Edge Size: 5

-> Mesh: Volumes

Shape: Hex: Mapped

and then Mesh

Mapped Meshing

Partition of solid model Mapped mesh in all volumes

Sweep Meshing Sweep Meshing is usually used to

match volumes with different mesh shapes and densities. So it is less control like free mesh.

MeshTool -> Uncheck SmartSize -> Size controls: Global -> Set: Global Element Sizes ->Size Element Edge Size: 5 -> Mesh: Volumes Shape: Hex/Wedge: Sweep Auto Src/Trg and then Mesh

Checking Mesh

After meshing, make sure checking your mesh with some criteria.

IN ANSYS, using the following two:

Element distortion (checked by the angle)

Element connectivity ANSYS Main Menu: Preprocessor->Meshing ->Check Mesh ->Individual Elm ->Connectivity