Week 7- Meshing of Backdoor Challenge

OBJECTIVE:- To mesh the given backdoor geometry of a car also ensure that mesh is of highest quality with low number of trias and good mesh flow.

CAD MODEL IMAGE:- 

IMPORTING:-

• Hence we are importing a given CAD geometry into hypermesh.
• There are file formates like IGES,STEP,Parasolid where we can import these file formats into any CAD,CAE Softwares.

IT IS COMPRISED MAINLY OF THE FOLLOWING COMPONENTS:-

PROCEDURE:-

• The part needs to be meshed component by component so we need to pick one of them and extract its midsurface. We will need to carry out this manually.
• By assessing the Car Backdoor CAD model.We can see there are three components in the model, so we need to create three different component mention below.
• Inner Panel
• Upper Body
• Lower Body

EXTRACTING MIDSURFACE:-

• Before extracting the mid surface,Delete the solids and then extract the midsurface cause we are not going to mesh on the solid.
  model.We are going to mesh on the surface.Ensure whether you have deleted the solids or not.
• In Geometry->">>>Mid Surface->">>>Auto Mid Surface.
• Extraction Options->">>>Use Skin Offset.This option will be able to capture the features properly.

                       

                       

                       

TOGGLING EDGES:-

• If there is any unnecessary lines,We can toggle that edges to get a proper mesh flow.
• In this component.In the fillet region,there some unneccessary shared edges so,toggle that edges also.If we
  mesh without toggling the edges,the element's will fail.

                                         

PERFORM MESH ON THE SURFACE:-

Tool bar → preferences → criteria file settings → checks for the element criteria →Enter values → apply → ok.

• [Note : Save the criteria file settings for that component and save it any other drives,Cause whenever we open that component,we can open the element criteria file and criteria will be applied habitually instead of entering again.]

                                                      

• As is customary with meshing, we should start meshing from a certain region and work our way from that region (preferably one with more free edges).
• To help with this, we can make use of cut lines (quick edit > split surface node) to split the surface into smaller surfaces for better mesh control.

                            

                            

                           

• After mesh is created, we can clean the mesh using various tools. Primarily, we will be using the element optimize tool, the drag tria tool and to an extent, the swap edge tool.
• These are accessed from the quality index section in the 2D menu.
• After we take care of each surface (meshing and cleaning up), we can move onto the next. The process is repeated until we mesh the entire component.

• Since the component is halved, we will need to make use of the reflect tool to create the other symmetrical half. Reflect tool can be accessed by going to the tools menu.
• We will need to select the elements to reflect first. Do take care not to select regions that are not otherwise part of the other half, since both halves may not be completely symmetrical. And then we can select the axis on which we are reflecting and then the base point. After that, we need to right click 'elements' in the reflect toolbar and select duplicate. And then we can click reflect. This will create the mirrored half of the current component.
  

                           

• We will now check for equivalency by going to the edges section in the tools menu and previewing equivalance for varying tolerances (ranging between 0.2 mm to 2 mm). This is to ensure there are no misaligned elements or free edges, which we can also check using a different option in the same section.
• The preview equivalence option shows us the nodes that require equivalencing. They are rectified by clicking the 'equivalence' option in the menu. If some nodes haven't been tended to, it may require manual fixing, using the replace node option (F3).
• After equivalencing, we can check for duplicates through the check elements tool in the same menu. If duplicates exist, we can click 'save failed', move on to the tool menu, select the 'delete' tool, select elements, right click element and select retrieve and then click the delete button. This should handle the duplicates.

                                 

•  Finally, we can assign a thickness for each of our midsurfaces. They all measure the same - 0.75 mm. We can do this by right clicking and creating a component in the component tree. After a property is created, we can go to its section in the bottom left and scroll down to assign the aforementioned thickness. Then we can assign the thickness by selecting the midsurface, going to its properties box on the bottom left and assigning a prop_id, by selecting the thickness property. Similarly, we can assign the MATERIAL as well through the same process.

FINAL MODEL IMAGES (MESHED)