Week 3 - 2D meshing for sheet metal

ANSA Live July Batch 1

Aim:

In this Hood model we have to create the midsurface after checking the geometry errors and mesh the component with the given quality criteria and after that assign the thickness.

Given :

S.No	Quality Criteria	Value
1	Target/Average length	5
2	Minimum Length	2
3	Maximum Length	7
4	Aspect	3
5	Warpage	15
6	Skewness	45
7	Jacobian	0.7
8	Minimum Quad Angle	45
9	Maximum Quad Angle	135
10	Minimum Tria Angle	30
11	Maximum Tria Angle	120
10	Tria Percentage	15

Stepwise procedure of hood model :

1. First have to Import the CAD model. Go to file >> open >> select model >> open.
2. After that we go for Cons resolution for that go to Mesh module > perimeters > length > select surface > give length > assign.

3. After the cons resolution we have must do Go to Topo module > faces > orient.
4. The next step is to check geometry. Go to Checks > Geometry > Execute.

5. The hood component is symmetric we are going to delete the another half part and then going to mesh and will transform tool.

6. Then measure the thickness for extracting mid surface of component.
7. Extract the midsurface using offset tool. For that go to topo module > offset > select the surface by feature > middle mouse > enter the thickness > hit middle mouse.

8. Before start meshing we have to measure the distance between two line if they come under the minimum length criteria we have to join them or delete them.

9. Fill the quality criteria and parameters for it.

10. We can go for the mesh the mesh. For that go to mesh module > mesh generation > best.
11. To hide another surfaces we can use or option and select one surface.
12. We can see the flow of element and trias that are back to back, opposite and rotating quadsso we can use reconstruction

13. There are some element fail to satisfy quality criteria after meshing
14. We can fix the them by using some commands
15. Paste, Swap , split, smooth, reconstruct.
16. Minimum length and maximum length :

• If element having any small edge length than predefined min length then it will fail for min length .
• If element having any edge length more than predefined max length then it will fail for maximum length criteria .

17. Skewness :

• for quad element = 90 –(Ømin)
• Distorted element will have skew value other than 0
• Ideal element will have skew value equal to 0.
• For tria element = angle between the meridian line & the mid node line.

18. Warping:

• Whenever quad element are sharing two different elements warpage error will occur.
• The angle between the normal of the bent element is known as warp angle .
• The quad element is bent along its diagonal i.e deviated from the plane .

After element cleanup:

Completed meshed model:

19. After all mesh done and quality checks we have to use transform option for reflect the half portion to the another symmetry side.
20. And next step is to assign thickness by 0.75 mm.

Result:

Learning outcomes:

1. We learn to perform basic opertions on any model like cons resolution , geometry check and correction.
2. Meshing of surface using shell mesh tools.
3. We learn to check quality criteria.
4. How to fix off elements.
5. We learn to deal with trias using spilt , paste , swap and join.
6. How to assign thickness to surface

Conclusion:

1. We meshed the given hood model manually.
2. Manaully meshing gives more accurate result to satisfy quality criteria.
3. Use of diiferent tools is Important to deal with meshflow , tria and