Meshing Back Door of an automobile using Hypermesh

Objective- Perform meshing on the Backdoor geometry of a car using Hypermesh.

Procedure

• Import the .stp file.

• Delete the solid part.
• Remove errors in parent geometry by increasing tolerance value given under quick edit panel.

• Extract the mid-surface using mid-surface option given under geometry tab for the inner,outer panel and lower body part of backdoor.

Outer panel

Inner panel

Lower body

Why do we extract mid-surface?

Mid surface is a surface between two surfaces. If we mesh the entire component in 3d the number of nodes and elements will increase which in turn would increase the storage space and processing power to analyze the component. To avoid this mid-surface is created where we represent the entire 3d model by mid-surface and create shell elements.

• Geometry can be cleaned using tools given under quick edit panel.
• Measure the distance between two points using distance option given under geom tab.

• Assign material and property card to the hood geometry.

Meshing

Why do we perform meshing?

The basic idea of finite element analysis is to make calculations at only limited number of points and then interpolate the results for the entire domain. Any continuous object has infinite degrees of freedom and it’s just not possible to solve this problem in this format. Finite Element Method reduces the degrees of freedom from infinite to finite with the help of discretization or meshing.

• Meshing is performed using auto-mesh option given under given under 2D tab.

• Meshing will be done only on half portion of outer panel and lower body part as both are symmetric.

Quality criteria

What is Quality criteria?

These are the parameters or the ranges upto which the ideal geometry or mesh size can be compromised or altered.

• Following Quality criteria needs to be followed:

• There will be many areas which will not follow the quality criteria.

• We will try to fix these areas using following tools:

Swap edge, Smooth, Drag tria elements, Node optimize, Element optimize, Split quad element, Combine tria elements.

• Using reflect option create the symmetry for Upper paner Lower body part.

• Below is the cleaned meshed model.

Learning Outcome

• Learned to extract mid surface.
• Learned assigning properties.
• Learned to clean the model using various tools under quality index.

Conclusion

• In this project the mid surfacing and meshing for Backdoor geometry of a car was successfully performed.