2D meshing of the backdoor of the hatchback car in hypermesh

Objective :

To perform 2D meshing on the backdoor components of the car as per the given quality criteria.

Procedure :

Step 1) Retrive and observe the geometry file

- First open the file of the hood having extension as .igs in hypermesh with radioss profile selected.

- After that delete the any solid if present. and observe the geometry by rotating, zooming.

Step 2) Midsurface extracted:

- After observing the geometry mid surface is extracted maually for each component.as the mid surface which was extracted by automidsurfacing was not proper.

- For extracting the mid surface manually first we have to calculate the distance between the two faces where we wanted the mid surface.

- Distance between the two faces is measured using distance (F4) command in geom menu and calculate the central distance from one of the node.

Step 3) Offset surfaces :

- To extract the midsurface we have to offset the surface at the middle of the two surfaces.

- Go to the surface edit (shift+F9) option and select offset. select the surface and before offseting the surfaces duplicate them. then enter the offset distance as per the requirement.

- In this way the midsurface is extracted manually for each component.

Geom > surfaceedit > offset > Surf > offset distance

Why we need Mid surface?

- If we assume that there is no midsurface and there is entire model, or suppose if component is 3D then it will create a 3D mesh,tetra or hexa elements. which will increase the number of nodes and also it will increase the number of elements which intern going to increase the storage space required to store the entire component and processing time and power which is needed for entire component.

-To avoid this we use midsurfacing, It is the representation of 3D model by surface and 2D elements. It creates shell elements which are 2D representation of hexa and tetra elements.

Step 4) Obtain surface to mesh:

- Hide the original component so that only midsurface is visible Now observe the geometry and perform cleanup of geometry using toggle edges at required locations.

Step 5) Generate Mesh :

- To generate the mesh click on 2D > automesh.

- Select the mesh type as per the requirement and enter the element size as 5mm. and click on mesh.

- After meshing we have to go through the given quality criteria.

- The given quality criteria is entered in check elements menu ( press F10).

- Check for the elements which are failing the above quality criteria.

Step 6) Remove Mesh errors:

- After the meshing is performed all the mesh errors are removed by using quality index, smoothing operation, drag trias, element optimization, replace nodes etc.

- All the mesh errors are removed and final mesh is generated for each component.

- Tools used while working on this model -

Rename- It is used to rename the components,curves,blocks,assemblies etc.

mask and find attached - All the elements will be visible which are attached to selected node.

Reflect - This command is used for mirror the elements, this is used for mirror the elements of outer body.

Duplicate - This is used while reflecting to keep the original elements,surfaces etc.

Project - To project elements on to the surfaces etc.

Replace nodes - By using F3 button as shortcut key this is used for minimising the gaps between the two elements or to eliminate any free edges present between two element.

Find edges(Shift+F3) - To display any free edges between the elements.

Conclusion :

1) Midsurface is extracted and we learn how to extract the midsurface manually.

2) By using element cleanup tools, and using some tools final mesh is achieved.