Week 3 - 2D meshing for Sheet metal

Objective:

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)

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

Given hood model

The hood model is imported into the ANSA and checked the model thoroughly if there are any multiple components are located. And then checked for geometry clean up by using the Checks>Geometry whether the model has any geometrical errors are like duplicate lines and bad surface etc...

• MAKE TOPOLOGY

Once deleted the duplicate lines and faces in the model make TOPO of the entire model when completing the TOPO make sure the component has properly stitched and observe the outside perimeter should contains single cons and every two joining surfaces should be double cons. Checked the whole component to avoid triple cons.

• Identify the model (Measurements)

Checked the dimension of the model whether it is carrying uniform thickness or any difference in the thickness.

• Extracting the mid surface

After completing the Topology and identifying the measurement, midsurface will be extracted by using the option FACES>offset the individual surfaces can be extracted and another option is also there to extract entire the surface at once by using the option FACES>midsurface it will take auto mid of the component, there is another option to extract the surface from one direction by using feature area <40° by selecting this feature the one side of the surface will only select and then offset it by half of the thickness.

• Create Set PID

After completing the extraction of mid surface create a new property ID by using an option FACES>SET PID and give the property values.

• Quality criteria

After creating the property ID for the midsurface assign the quality criteria parameters which are given.

• Mesh generation

After completing the property ID set the geometry parameters and macros for 5mm by using the length in the perimeter option of the mesh tab and if the model is symmetry then delete the half portion in the cad model because when transforming the symmetry of the mesh surface will regenerates along with mesh.

After deleting the half portion of the surface mesh should be generated by using the option mesh generation>best try to make partisans in the model parallel to the perimeter for achieving the better mesh if in one shot mesh is generated with so many trias then go for reconstruction option to achieve the best mesh. If the trias still generated try to avoid it by using split option.

After completing the mesh transform the total mesh and make symmetry with using three points in the edge of the perimeter.

CONCLUSION :

• Basics of ANSA GUI.
• Make geometry cleanup.
• Extract mid surface.
• Set PID.
• Create quality criteria.
• Mesh the surface.