Week - 4 - 2D meshing for Plastic components

Ansa july live batch 1

Aim : In this plastic 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.

S.No	Quality Criteria	Value
1	Target/Average length	1
2	Minimum Length	0.5
3	Maximum Length	3
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 plastic model :

• We have to Import the CAD model

(file>open>select model>open)

• In the IGES & STEP file, Cons resolution must do to get proper resolution in curve areas:

(Mesh module>perimeters>length>select surface>give length>assign)

• After the cons resolution we have must do orient:

(Topo module > faces >orient)

• The next step is quality criteria setup and parameters setup:

• The next step is to check geometry
• (Ckecks>Execute)

The main intention of Geometry clean-up is to eliminate single CONS and Reduce triple CONS as many as possible.

• As we know that this is plastic model having different thickness in surfaces, we desided that we can go to casting method.
• Casting gives the result as a FE in the middle automatically.
• If we can go with manual middle tool, then it will take more time that casting.
• (Topo>midsurface>casting)

After completion of casting we can see that the FE model which is not proper captures the entire surface so that we have to do some correction in the FE with the help of Align manager

• We had created shortcut key for align manager that is alt+A

• After align all surfaces as per parent geometry we have to fill or create FE surfaces as per original surfaces.

• After all this correction we have to work on OFF elements.
• For clear this all off elements we can use reconstruction option
• We can also use split , swap, smooth ,improve option for clearing all the OFF elements.

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 .

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.

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 .

Final model of plastic FE

Learning outcomes: In this model i had learnt about.

• How to do geom checks
• How to do casting for Fe
• How to work on align manager
• How to check quality criteria
• How to clean fail element
• How to reduce back to back trias , opposite trias ,rotating quads and trias near the feature line .
• How to assign thickness.

Conclusion: finally we got our mesh model for finite element analysis using ansa software.

Conclude

Casting method reduces time over manual midsurface .