Project 2- 2 D MESH OF REAR WHEEL PANEL

#PROJECT 2 REAR WHEEL PANEL

AIM : 2D Mesh of Rear Wheel Panel Body and Assigning Thickness.

ABSTRACT : The back wheel panel compartment is most often located at the trunk or rear of the vehicle. Trunk of a car is the vehicle's main storage or cargo compartment, often a hatch at the rear of the vehicle.

OBJECTIVES : Generating mid surface and 2D mesh after geometry clean up on back wheel panel body of car and assigning thickness with following quality criteria -

Target element length : 5mm

Minimum element length : 2mm

Maximum element length : 8mm

Minimum quad angle : 45

Maximum quad angle : 135

Minimum angle tria : 20

Maximum angle tria : 120

Tria percentage : 15

Aspect ratio : 5

Skewness : 45

Warping : 15

Taper : 0.5

PROCEDURE:

STEP 1: Duplicate the parent surface model to another collector to keep the parent surface safe.

STEP 2: Organise the parent surface to another component collector and duplicate the surface and move

*Tool>Organise>surface>set current component>select dest component>Duplicate>move.

STEP 3: Switch to the surface of components and remove fillets if any which are less than given mesh size

*Geom>defeature>surface fillet>select surface displayed>give min and max radius>find>remove

STEP 4:

• Delete the unnecessary surface which is less than element size so it will not create bad mesh

*F2>surface>select surface>delete entity

• Fill the void surface

*Geom>quick edit (F11)> filler surface>select boundary line of the circle

• Toggle the line

*Geom>quick edit (F11)> Toggle edge>select boundary line of the circle

• Quick Edit Panel

STEP 5: Check the thickness of the component- To get the exact thickness of the sheet we can proceed with the following command.

• Create a node to any one side of the sheet metal

*Geom>temp node>nodes>select surface>press left click to add the node>add

• Project this node to the opposite side of the surface after duplicating the node.

*Tool>project >nodes>select node>duplicate>current component>to surface>Select surface>Project

STEP 6: Measuring the distance between two nodes which gives as the actual thickness of the sheet.

*F4 or Geom>distance>two nodes>select both nodes by N1,N2 and we’ll see the distance.

STEP 7: Repeat step 4 and 5 to few more surface to get sure about the thickness at different surface.

• This measuring thickness will help us to know whether there is any surface which has varying thickness and also help us to assign thickness to 2D elements after generating mesh.
• In this case there is no varying thickness so we can proceed to generate midsurface.

STEP 8: Creating Mid surface of the back wheel panel body.

*Geom>mid surface>auto mid surface>auto extraction>surfaces>displayed/all>extract

• After creating the mid surface of that particular component we have to proceed for geometry clean up on the mid surface to get a better mesh result by quick edit panel. We have to toggle the unnecessary lines and remove free edges. We can split surfaces which will help us to mesh the surface properly and adding points to create a split surface by node or line.

*Geom>quick edit or (F11)

STEP 9: We can move the surface of the components to another collector so that we can work on the inner and outer side of the back wheel panel separately.

STEP 10: We can mask the one side of the component because there are many surfaces which are symmetric but we have to again work on asymmetric surfaces as well.

*2D>connectors>mask>surface>mask or (F5)

• We can see free edges, unsuppressed lines and suppressed lines

*Toolbar>By topo

STEP 11: After cleaning up the geometry we can now proceed for 2D mesh on the surfaces one by one.

*2D>automesh>surface>select surface>set element size(5mm)>set element type(Mixed)>mesh

STEP 12: Rotating the mesh elements

• Creating a single node at the center.

*Geom>nodes>arc center>lines>select lines>create

• We’ve to rotate the mesh to 120 degrees angle two times because there are two different types of pockets, three are facing upwards and another three are facing downwards.

*Tool>rotate>elements>select elements>z-axis>select base node(center node)>give angle(120)>rotate+ or rotate-

STEP 13: After completing the mesh on each mid surface check and remesh few elements to avoid trias elements as possible to get proper mesh flow.

STEP 14: Check for the failed elements which violets given quality parameters by setting up criteria file setting as per given data.

*Menu Bar>preferences>Criteria file setting

• We have to mind the given quality criteria, we can check elements by following command-

*Toolbar>element colour mode>by element quality

STEP 15: Correct the failed elements by Quality Index Panel and 2D remesh Panel.

STEP 16: Mesh elements should capture the given feature surface by Project panel.

*Tool>project>nodes>select nodes>to line>select lines>along vector>line normal>project

STEP 17: Reflecting meshed elements to the opposite side.

NOTE : ONLY THAT ELEMENTS CAN BE REFLECTED WHICH HAS SYMMETRIC SURFACES AND HAVE TO WORK AGAIN ON REMAINING ASYMMETRIC SURFACES.

STEP 18: Moving Mid Surface and Mesh to one collector component as we have made it separate in STEP 9.

*Tool>Organise>surface>set current component>select dest component>move.

*Tool>Organise>elements>set current component>select dest component>move.

STEP 19: Finding free edges of elements after moving elements to single collector

• Finding disconnections between elements

*Shift+F3>components>select components>give tolerance>find edges>preview equivalence>equivalence.

• Connecting nodes of the elements by replace-with nodes panel. *F3

STEP 20: Assigning thickness to all the meshed elements

• Measure the thickness of the parent component by following step 5.
• Create Property collector in model tree panel.
• Rename it and mention it thickness

• Give the thickness manually in that particular collector details panel.

• Assigning Thickness

• Viewing Thickness of elements

*Toolbar>element colour mode (By Property)

*Toolbar>2D Detailed Element Representation

RESULTS:

• Final Elements Quality

• Final 2D Mesh of Rear Wheel Panel

LEARNINGS:

• Organising surfaces and elements(Step 1, 2 and 18)
• Geometry cleanup using a quick edit panel. (Step 4)
• Measuring distance by projecting nodes. (Step 5 & 6)
• Extracting the mid surface from the parent component. (Step 8)
• Masking and unmasking surfaces and elements. (Step 10)
• 2D Meshing (Step 11)
• Rotating elements. (Step 12)
• Setting up criteria file. (Step 14)
• Fixing failed elements using quality index panel and remesh. (Step 15)
• Projecting element’s nodes to feature surfaces. (Step 16)
• Working on an asymmetric surface. (Step 17)
• Reflecting elements. (Step 17)
• Finding free edges of elements and fixing it (Step 19)
• Assigning thickness. (Step 20)