Week 12 - Project-1

GENERATING MESH ON PLASTIC COMPONENT OF A PASSENGER VEHICLE SIDE DOOR

Computer-aided engineering (CAE) software has been used for many years in the plastic industry, identifying the most appropriate mesh geometry and density remains a challenge. It can affect the accuracy of the simulation, the time and the costs.

OBJECTIVE: -

1. Perform topology cleanup and manual midsurface extraction.
2. Create 2D elements meshing of good quality.
3. Check elements according to the mentioned quality criteria.
4. Assign thickness to the components.

PROCEDURE: -

• Import the Side door file using import geometry tool.
• Since the geometry is complex and it's thickness is varying along the cross section, we need to divide the component into several segments. Also, defeature all the fillets which can cause the elements to fail for minimum element length criteria.
• The midsurface of the geometry is extracted using the offset command under surface edit panel. Carefully offset the surfaces by putting 1.4 as offset distance. Use translate and surface edit tool to attach the surfaces. We can also join the surfaces using toggle edge and replace edge options.

fig: MANUAL MIDSURFACE AFTER TOPOLOGY CLEANUP

• Cad geometry has topology details that interfere with mesh quality. So we need to cleanup the geometry first by using "Quick edit panel". Remove the unnecessary points, suppress edges and replace fixed points options so that we can achieve a proper mesh flow.
• Select a small area of geometry and use the Automesh panel and size and bias meshing method to create the mesh. Set the mesh type as mixed and the element size as 4units.
• We can achieve a better mesh pattern in the intial stage by alter the individual densities of elements. Remesh the existing meshes and try to maintain a constant size for elements.
• The check elements panel allow us to investigate each specific element criteria, view a breakdown of all failed and worst elements, resolve all criteria violations at one time, and evaluate the over all quality of a mesh.
• Use the cleanup tools in the quality index panel to fix the elements which are failing. Place node option can be used to get rid of the elements which are failing for maximum length. Similarly drag tria elements and combine tria elements can be used to fix the worse elements. By editing the elements i.e. spliting the elements and creating we can eliminate the failing elements.

fig: MESH AFTER REMOVAL OF ERRORS

• Apply Smooth command to make the small adjustment needed to get the curvature for the entire mesh.
• Use equivalence to remove the coincident nodes, based on a search tolerance which we can specify.
• In order to perform the model checkup go to tools menu and select normal tool. We can adjust the direction of normal if there are some kind of discontinuity.
• To provide thickness we need to create property and assign thickness to the components subsequently.

fig: SIDE DOOR AFTER ASSIGNING THICKNESS TO THE COMPONENTS

CONCLUSION: -

1. Performed the manual midsurface extraction, topology cleanup and 2-D meshing for the components.
2. Achieved the mentioned quality criteria for the side door.
3. Assigned thickness to the components.

LEARNING OUTCOMES: -

• Understanding about how meshing on automotive parts are carried out.
• How to assign thickness to the components.