Mesh cleanup on 2D SHELL elements.
OBJECTIVE
The objective of this project is to perform geometry clenup operation,there should not be any free edges, convert all them into refine geometry. and extract the mid surface and clean midsurface geometry and create the 2D mesh with given target element lengh.
Finally assign the proper thickness, by creating a generic property on the given models:-
1.Practice
2.Mounting Bracke
3.Clip Repair
INTRODUCTION
Hypermesh is a high performence finite element pre-processor to prepare even the largest models, starting from import of CAD geometry to exporting and analysis run for various disciplines.
A Shell element is also called as 2D element and it's divided into two types basically:-
- Four noded element also called quad element.
- Three noded element also called as Tria element.
STEPS PERFORMED WHILE DOING 2D SHELL MESHING
- Importing Model:-
Hypermesh is opened with Radiossis as user profile and CAD file was imported
A)PRACTICE
B)MOUNTING BRACKET
C)CLIP REPAIR
File-->Import-->Geometry-->Select file format(IGES)-->Select the CAD file-->Import
2. Geometry cleanup or repairing CAD:-
Within the geometry ribbon, we have geometry cleanup tools. These tools allow us to create and edit surface as well as remove rounds, fillets, cutout and holes from geometry.
3. Generating Mid surface:-
Mid surface is created to the imported CAD geometry because of the small thickness. This process reduces the meshing time as well as it increases mesh quality. At first on the visualization tool bar, clicked to "shaded geometry and surface edges" and selected "mixed" to change the geometry color mode.
A)PRACTICE
B)MOUTING BRACKET
C)CLIP REPAIR
Geometry-->Mid surface-->Auto mid surface-->Extract-->Done
4. Mid surface cleanup:-
i) All the holes having lesser dia than 5mm are eliminated from the mid surface using defeature.
Geometry-->Defeature-->Pinholes-->Select the surface having holes-->Give dia limit(5mm)-- -->Find-->Delete.
ii) Toggled the necessary surface edges, from free to shared to supressed with a single mouse click on the edges.
Geometry-->Quick edit-->Click on the "toggle edges"-->Click on the edges needed to toggle.
5. 2D Shell mesh generation:-
Once the geometry cleanup and mid surface cleanup is successfully done, next is 2D shell meshing.
i) According to required element parameters(max size, min size, skew, jacobian, warpage etc..) are given in Criteria file editor.
Preferences-->Criteria file settings-->Criteria-->Unckeck the "Advanced criteria table"-->target element size-->give all required parameters-->Apply-->Ok.
ii)2D shell mesh generation
A)PRACTICE
B)MOUNTING BRACKET
C)CLIP REPAIR
2D mesh-->Auto mesh-->Select surface-->Give the element size-->Mesh.
6. Quality Check:-
This process of quality check let us know about the quality of elements created, are meeting its required parameters or not, while meshing the mid surface.
for these models these were the fixed required parameters:-
Target element size:- 5
Max element size :- 7
Min element size :- 3.5
A)PRACTICE
B)MOUNTING BRACKET
C)CLIP REPAIR
7. Assigning the thickness value:-
After successfully creating the 2D shell element on the mid surface , all the elements are moved to the original part and then thickness of the respective models is assigned.
THICKNESS VALUE:-2mm
A)PRACTICE
THICKESS VALUE:-1.8mm
B)MOUNTING BRACKET
THICKNESS:-0.91mm
C)CLIP REPAIR
CONCLUSION
On the given models successfully 2D Shell meshing is performed with target element length 5mm, within the minimum element size 3.5mm and maximum element size 7mm. And finally the thickness was assigned as required. Thus all objectives are achived successfully.