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)

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

OBJECTIVE

· Geometry cleanup of CAD model

· Mid surface generation

· Generate mesh as per given quality criteria

· Eliminate possible number of tria and rotating quad elements and also eliminate tria density nearer to feature lines.

PROCEDURE:

To get proper Mesh flow over the entire model, we have to choose best possible process of pre-processing software, with ANSA Best possible process of pre-processing are:-

1. Geometry cleanup
2. Topological activity
3. Mid-surface generation
4. Set PID
5. Defining mesh parameters and quality criteria
6. Mesh generation
7. Mesh flow and mesh quality improvement

Importing the hood model in ANSA….

Geometry cleanup

From checks manager we can perform Geometry check, ANSA can fix some geometrical errors automatically and some are fix manually.

fixing geometrical errors

Zoom in and isolate the entity showing unchecked faces along with all attached entities.

Only inner extract part has geometrical errors as unchecked faces and needle face.

All geometrical errors are automatically fix by ANSA.

Topology Activity

Topology describes how different faces and features of geometry are connected with each other.

Topological activities are performed to prepare the model for proper mesh flow with less tria concentration.

Mid surface generation

• Measure the uniform thickness of component in order to generate mid surface manually.

Using OFFSET COMMAND we can provide offset value in direction of orientation as thickness/2, to generate mid surface manually.

Creating mid surface of each component one by one by offset command.

Defeaturing

If distance between cons are less then minimum element length criteria, then we go for defeaturing because element formed between cons are failed for minimum element length criteria.

Defining mesh parameter and quality criteria

Before mesh generation we have to properly define mesh parameter and quality criteria, then only mesh generation follow user define quality of mesh for different application.

Mesh generation

Mesh generation is the process of discretization of entire model into required finite number of elements.

Mixture of quad and tria elements

Steps follows to get proper mesh flow:-

• Meshing of components face should be start from centre to end to eliminate triangular element easly.
• Outer hood has large surface area, therefore project cuts should be mark before mesh generation to get proper mesh flow.
• 
  By BEST Mesh generation command, generate mesh on each and every component of model.

Mesh flow and mesh quality improvement

1. RECONSTRUCT
2. SMOOTH
3. SPLIT, SWAP, JOIN
4. Changing Nodal number
5. Edge2edge perimeter

THEREFORE THICKNESS IS ASSIGN ON P SHELL MESH AS PER MEASUREMENT OF EACH COMPONENT.

Learning outcome

• Fluency in Handling ANSA GUI.
• Develops better understanding of commands and its application.
• Enhanced better understanding of construction lines and features lines of model.
• Able to perform topological activity without disturbing features of model.
• Understand better mesh generation methodology.

Conclusion

Obtained shell mesh for given components.

Total number of elements obtained are 1,02,228 elements.

No off elements, elements will capture entire surface of all parts.

Total elements- 1,02,228

Quad elements- 1,00,840

Tria- 1388

Tria%- 1.3