Comparison in Meshing Method In ANSA (Manual, Batch and casting Mesh)

1. Objective:

For the given component, checking for the geometrical errors, Taking the Mid surface and meshing the Mid surface with the given 2D element Quality Criteria and assigning thickness to it. Performing three cases using the following Quality Criteria.

S.No	Quality Criteria	Value
1	Target/Average length	3
2	Minimum Length	1
3	Maximum Length	5
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

2. Procedure:

First, we are going to import the model and Check the Geometrical Errors using Check Manager.

Now Measure the thickness of the sheet metal part. Here we can see that the thickness is uniform which is 1mm.

We have to perform three types of Cases on this hence saving the model. Performing Three Cases of Extracting Mid Surfaces and Meshing as follows.

2.1 Procedure Case-1: Use the Manual approach to take Mid surface, Use the Manual meshing approach for 2D meshing

Step 1: Importing CAD Model

Importing the CAD Model using an open tool.

Step 2: Extracting Mid Surface

We already Fixed the Geometrical issues so now we can extract the mid surface manually.

To do it we are going to use the offset > faces option > select the faces > offset it (-0.5)

Now After Extracting the Mid surface using the Topo tool and Again Checking the Geometrical Error.

Step 3: Setting up Geometry.

Now we are going to modify the geometry by making Nodes of Holes to even numbers and Parallel to the nearest edge using Num +/- and slide tools. Which makes the proper Mesh Flow.

Step 4: Setting up Quality and Meshing Criteria.

Before Going to do meshing we need to define its Quality Criteria and Meshing Criteria as follows.

Step 5: Meshing

Use the cut option to make separate areas and do spot mesh. Use reconstructs and regenerate option and mesh it.

Note: use Mark and Unmark option otherwise the created modification in the holes will be restored while meshing.

Use the Join option to remove the user cuts using a combination of the keep and Reconstruct mesh option.

The Smooth option is used to improve the mesh quality.

Step 6: Fixing Quality issues

Using Reconstruction, Smooth, Num+/-, and other tools to fix the mesh quality issues as shown.

Step 7: Final Mesh

Now finally we have a Model without quality issues

2.2 Procedure Case-2: Use the Casting method to take Mid surface and 2D Meshing

Step 1: Extracting Mid Surface

Use Mid Surface > Casting tool to get automatic Mid Surface.

Enter the value of Minimum thickness and Target Element Length as shown.

Step 2: Mid Surface

Now we can see that the following is automatically generated mid-surface.

Step 3: Fixing Quality Issues.

Using Improve tool for Fixing the Quality issue. Also, Using Reconstruction, Smooth, Num+/- and other tools to fix the mesh quality issues

Step 4: Final Model

Finally, we have the Mesh model without quality issues.

2.3 Procedure Case-3: Use the Skin method for taking Mid surface and Batch meshing for 2D meshing

Step 1: Using Skin Option

Goto Faces module in topo Menu > Mid.Surface > Skin > Select the Surface

After selecting the surface, the three regions are highlighted as Green, Red, and Blue. Where Green and Red are indicated the two sides of surfaces and thickness are represented by the blue color as shown below.

Now define the mid surface as shown

Step 2: Setting Up Quality Criteria

Setting the meshing and Quality Criteria as follows.

Step 3: Setting up Batch Meshing Parameters

Goto Batch Mesh Manager > Create New Scenario > Meshing Scenario > double click on contents > select the components > move it to the items using the green button

Again, Check Mesh and Quality Parameters in Meshing Scenario and Run the Meshing process.

Step 4: Fixing Quality Issues

After Meshing we can see the Quality Issues associated with the Model which we can fix with previous methods.

Step 5: Final Mesh

Now we have meshed the model without quality issues as shown below.

3. Comparing All the Results
   • In Manual Meshing, we need to use the offset option and manually select the faces and also need to define its offset value as well as direction.
   • The time taken is too high because we need to mesh it area by area using the spot meshing option. The Quality issue is very high due to human error.
   • In the Casting, we got our mid surface along with the mesh too quickly. The mesh generated is based on as we defined the Target Element length. The Quality issue is very less as compared to Manual Meshing. In the Casting Method, the Time taken to generate mid-surface and Meshing is very less and the only time is taken to fix the Quality issue.
   • In the Batch Meshing the Mid surface, generation is also very quick, and also very minimum time is required to set up the batch meshing.
   • The Quality issue after Batch Meshing is Drastically low as compared to the other two methods. Hence, we can say that the Batch Meshing along with the skin method to take mid-surface is the fastest method, the second-fastest method is Casting and the Manual Method is the slowest method.
     • Note: When we mesh the sheet metal components using batch Mesh, the mesh is not removed from the components While in Casting the mesh is independent of the geometry.