Week 3 - 2D meshing for sheet metal

Report

AIM:

For the given Hood model, Take the mid surface for all the components after checking the geometrical errors and mesh the mid surface with the given element Quality criteria. (Refer the table Below for the Quality criteria)

Quality Criteria:

Procedure:

following step to be done for meshing the given Hood Model.

1] Import:

import the geometry in the .stl,.STEP,.IGES format. File > Open > Choose the File and hit on open.

2] Cons resolution:

changing the distance between the nodes(mesh length) from preset value to required value,this will help us to understand the actual shape/ geometry of imported cad model.make sure before meshing this length should be change again to the targeted element length.(mesh module>perimeter>length>1)perimeter2)macros)

fig 1] before cons resolution:

fig 2] after cons resolution:

3] Topo option:

• If the imported file it doesn’t have any connectivity between the Surfaces.To get the connectivity between the surfaces we have to use the Topo option.(TOPO Module> Faces > Topo).
• first we check the any single cons are present in the geometry so in focus menu deselect the double cons and press shit+ctrl.
• if any double cons present then use the (TOPO Module> Faces > Topo).

4] orientations:

• We have to Orient the Surfaces to make sure all the surfaces are in one normal direction.(TOPO Module> Faces > Orient)

5] Checking the geometrical errors:

after the orientations done the we need to check the geometrical error. for that go to (check manager>geometry>execute)

6] Clearing the geometry errors:

if any geometry error is pop out then select the all error and then right click on error and fix them.

7] Check the thickness of the components.

• If the thickness is less than 5 or 6mm then we have to extract the midsurface.
• If the thickness is more than 5 or 6mm then no need to extract the midsurface.

for cheching the thickness of model (isolate>mesure>nodes) or create short cut key for measure option.

8] Creating the midsurface for a sheet metal Component.

• If the components have the uniform thickness then we will be using the Skin or Offset options to extract the midsurface.
• If we are using the skin method make sure that unchecking of Delete original surfaces in the options list.(topo module>faces>mid surface>skin/casting)
• If we are using the Offset option, we will be using the feature selection to get the mid surface in an easier manner. While providing the offset value we have to make a change in the options list from use existing to auto create for the property.(topo module>faces>offset)

Mid-Surface for outer panel:

9] Providing the Target element length:

changing the distance between the nodes(mesh length) from preset value to required value,make sure before meshing this length should be change again to the targeted element length.(mesh module>perimeter>length>1)perimeter2)macros)

10] Providing the Mesh Parameters.

based on the given data we provide the target element length is 5 mm,minmum target length is 2 mm,and maximum target length is 7mm etc

11] Providing Quality criteria to the models:

based on the given data we provide the Quality criteria to the models.

12] Cleaning the Midsurface extracted:

• If there are any unnecessary hotpoits we will be using the Delete option in Hotpoints group to avoid or we can use the insert option with right mouse click.(topo module>hot points>insert/delete)
• If there are any construction lines which will affect the mesh flow we will avoid them.(topo module>face>cut)
• If there are any two feature lines which are very near to each other and the distance between them is less than your minimum then you will be suppressing any one of the line.(topo module>face>cut)
• Feature Line:- We call a double con as a feature line when the surface after that double has significance change(Flat surface may be attached to a curved surface or viceversa) in the geometry.

13] Spliting the surface in the small square-like structures:

spliting the surface in the small structure so that mesh flow is in proper way and its avoid the tria in the mesh flow.so that quality of generated mesh is good.and also its easier to engg.to generate the mesh.

14] Generating the Mesh:

for creating the mesh we use the lot of command but i explain some of them.

creating the mesh: (mesh module>mesh generation>best)

smothning the mesh:(mesh module>shell mesh>smooth)

reconstruct the mesh:(mesh module>shell mesh>reconst)

improve the quality of mesh:(mesh module>elements>split/swap/join/stich)

insert or delete hot points:(mesh module>hot points>insert/delete)

to increae or decrease elements number:(mesh module>perimeters>NUM+/-)

to cut or join the face:(mesh module>macro>cut/join)

to delete the mesh:(mesh module >mesh generation>erase)

1] latch:

2] hindge support1:

3] outer pannel:

4] inner pannel:

15] Assign the thickness:

Assign the proper thickness for the newly created midsurface so that (quality criteria>presentation parameters>check the draw shell as solid)

16] check the whole model for Quality criteria:

here its showing the out of total 94737 mesh elements 244 elements are OFF(failling in Quality criteria).