Week 3 - 2D meshing for Sheet metal

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)

Objective:

To generate model free of geometrical error

To generate mid surface

Generate mesh with proper mesh flow, with target element size of 5 unit.

To generate mesh as per given quality criteria

Procedure:

Import the CAD model of a HOOD assembly into ANSA interface.

Fig Hood model

Perform an initial geometry check and fix the errors if any.

After topo

Visually check the orientation and rectify if any discrepancies arise.

In the mesh interface, quality criteria and mesh attributes are assigned as required. Length command is used to assign average length in to the model.

Mid surface generation

Mid surfacing has to be achieved manually. Using offset command, mid surface is generated. After creating a Mid-Surface, Click Faces →Set PID option and create New PID for Each component in the properties. The mid surface generated is isolated and saved as a new PID.

Outer hood model

Outer hood model is symmetric hence half of the similar part is deleted

prepare proper construction line for better mesh flow and avoid minimum element length.

Meshing:

After meshing , using symmetry

Classic mesh > Mesh generation > Best > select surface > click middle mouse button.

Then we need to check mesh flow and for improving mesh flow we need to use commands like Reconstruction, Improve, Fix quality, Split, Join, Swap.

Similar operation can be done on Outer hood as well. Since outer hood is also symmetric except the latch portions. latch portion should not be considered while taking the symmetry.

OR command can be used to hide the latch.

Entire quality after mid surface generation

Mesh and mesh quality:

The generated mesh may have triangle originating from the entity or originated on the feature line. This must be corrected to get the good quality mesh. To obtain the good quality mesh. For improving mesh flow, we need to use commands like Reconstruction, Split, Join, Swap, paste option.

Reconstruction is powerfull tool to get the qulity mesh it is available under the shell mesh option.

Additional panel for lock mechanism

Additional support for hinges

Fig Entire model after meshing

Learning outcome:

• Learned ANSA GUI and its commands.
• Preparing geometrical error free model for preprocessing.
• Understanding the importance of construction lines and feature lines of the model.
• To make the topological activity without disturbing the features of the model to get good mesh flow. Correct the feature line to get the good mesh flow.
• Mesh generation methodology.
• Balancing the Model’s feature and the Mesh element quality.
• Using various options to improve the Mesh quality and Mesh flow.