Week 12:Project-1-Meshing of Door Inner Panel Challenge

OBJECTIVE:

To mesh the given Side Door Panel by following the given Quality Criteria and to assign the corresponding thickness to the elements.

INTRODUCTION:

A door panel is an insert on the door of a vehicle. Door panels serve as an interface between the interior of the car and the inner workings of the door, and between vehicle occupants and the door.

Fig: Door Panel

CAD MODEL IMAGE:

Fig: Side Door Panel Model

PROCEDURE:

1) Import the model into Hypermesh.

The given side door model is imported into Hypermesh using the import option on the menu bar.

Fig: Importing the model

Fig: Imported Model

2) Geometry Cleanup

Before extracting the mid surface from the model, ensure that the model surface is perfect and free from errors like free edges, duplicate surfaces and missing surfaces. If any defects are found then the required geometry cleanup needs to be done using the various tools such as toggle edge, filler surf, replace points etc. available under the quick edit panel. (F11 (or) Geom>quick edit)

Fig: Quick Edit Panel

On the model, if there are any lines that are too close to each other or if the distance between the lines is less than the minimum element length, then one of the lines needs to be suppressed using the toggle edge option. Otherwise, on meshing, elements that fail the minimum element length criteria will be created between the closely spaced lines.

Fig: Toggle Edge

Also, to ensure proper feature capturing and to prevent the creation of elements that fail minimum element length criteria, it is necessary to remove small fillets that fall below a specific radius. This is done using the surface defeature tool. (Geom>defeature>surf fillets)

Fig: Defeaturing of Fillets

Fig: Defeatured Fillets

Fig: Model after Geometry Cleanup

3) Mid surface extraction

Since the model is complex in nature, for ease of meshing and to ensure proper mesh flow the surface is split into 4 parts and the split parts are organized into different components.

Fig: Model Split into four parts

Fig: Model Split into four parts

The midsurface extraction is possible through the ‘auto midsurface’ option or through manual offsetting, but here, due to the complexity of the model, ‘auto midsurface’ feature does not generate a proper mid surface and manual fix-up of this generated mid surface will take up a lot of time and effort.

Hence, the mid surface is extracted using the offset tool. Using the offset tool the outer surface of the door model is offset by a distance that is equal to half of, the distance measured between the outer and inner surfaces of the door model. (Geom>surface edit>offset>select surface and duplicate>specify distance>offset)

Fig: Measuring Thickness

Fig: Manual Offset of Surface

Fig: Mid Surface obtained after offset

For extracting the midsurface of the ribs having varying thicknesses the following method is followed.

Using the ‘midline’ option in lines tool, a midline can be drawn on the surface of the rib.(Geom>lines>Midline>select lines>create)

Fig: Creating Midline on Rib Surface

Next, trim the base midsurface with respect to the drawn midline. Thus, a shared edge is created on the base surface.

Fig: Trim base surface with the midline

The ‘ruled’ option under ‘surfaces’ is used to create a surface between the midline and the shared edge created. The surface thus created is the midsurface of the varying thickness rib.

Fig: Rib Midsurface being created using 'Ruled'

Fig: Rib Midsurface

For midsurfaces of ribs obtained through manual offsetting and are not connected to the base midsurface, the connection can be made using the ‘extend’ option under ‘surface edit’ menu.

Fig: Extending Rib Midsurface to the base

Fig: Rib Extended

4) Meshing of midsurface

The given quality criterias need to be specified using the criteria file editor before meshing the model.

Fig: Criteria Editor

Once the quality criterias are set, automeshing is performed with a target element size of 4.

Fig: Meshing

5) Ensuring proper mesh flow and quality of elements generated

The generated mesh is examined properly to ensure that there is a proper mesh flow. Also, the number of trias should be kept to a minimum. Ensure that there are no rotating quads, back to back trias, opposite trias or trias on feature line.

Fig: Removing Opposite Trias

Fig: Mesh Cleanup

Check if any elements are failing for any of the given quality criterias. If any element is found to be failing the given quality criteria then the cleanup tools are used to correct them.

Fig: Meshed Model

Fig: Meshed Model

Fig: Quality Check of Elements

5) Assigning thickness

After meshing, the elements have to be assigned the required thicknesses. All of the elements are assigned to different component collectors based on the thickness of their parent geometry and they are renamed according to their thickness.

Next, properties have to be created for all the components. (Right click tab area>create>property)

Under the property menu the thickness ‘T’ has to be specified. Also, other properties like the material and card image can also be specified if needed.

Fig: Creating Properties

To assign the property to the component, right click on the corresponding component and choose the ‘assign’ option. In the pop up menu select the corresponding property from the drop down list and apply.

Fig: Assigning Properties

Fig: After Assigning Properties

FINAL MODEL IMAGE:

2D Detailed Element Representation:

CONCLUSION:

The given side door panel was meshed according to the given quality criterias after extracting the midsurface. Also, the required thicknesses were assigned to the corresponding elements.