Performing RADIOSS Starter and Engine file manipulation and 3D Meshing of Arm Bracket.

1. Check the material properties of rail component and calculate the Speed of sound in Steel rail.

2. The length of rail is about 1000mm. Calculate the time takes for a shock wave to travel from one end of rail to the other.

∆t_c = =  =

Elemental Time Step =0.1950 ms     

3. Time for sound to travel the length of rail

1.HOUSING

• Choose the use profile as Hypermesh optistruct. Click on Import geometry.
• Use the geometry color mode and choose by Topo Mode.
• The component appears in wireframe mode. Change it o surface. At LHS we get the no. of component which we have to mesh. Here we have to we have to create component according to given geometry. namely

1. Hub - Solid Part- As topo mode show it in dark green color
2. Cover- Surface Part- As topo mode show it in light green.

• For 3D meshing we have 3 different ways.

1. 2D tria meshing and convert that to 3D tetra Mesh
2. 3D mesh Panel- Tetramesh
3. Volume TetraMesh
4. For crude and fast mesh- quick tetramesh

1. Geometry Cleanup

• Now we have fully equivalence mid surface. We have to clean the surface to get clean and clear meshing. It will avoid the pinholes, very small edge and surface fillets automatically. We have to set the parameters according to requirement.

• Go to defeature option and set the target fillets(max.radius and min.radius). Select the taget surface and hit on find. Hypermesh will automatically recognize the surface fillets not hot on remove. It will remove the fillets which we don’t want.

• Apart from that , Click on auto cleanup. Click on edit parameters. Se the parameters according to requirements. We have to decide it according to customer requirements and accuracy required.

Eg. Target Element Size= 5 as shown in picture.

• Now click on edit criteria. This is where we have to specify the criteria for the Quality index of meshing.
• These are the criteria on which our meshing gets checked on quality of meshing.

• E.g. Min/ Max Size of element, Aspect ratio, Warpage, Min/Max Quad angle, Scewness etc

  • Click on Apply and hit OK. Click on auto cleanup.
  1. Meshing
  2. 2D tria meshing and convert that to 3D tetra Mesh
  • Now go to 2D mesh panel or hit F12 on keyboard. Go to 2D elements. Select the surface displayed and set element size as 6. Mesh with only trias. Trias we are going to convert into tetras.
  • Hit on mesh. Adjust the nodes according to requirements. Make sure the mesh flow is good. Adjust each area of meshing with care to get a quality mesh. Hit middle mouse button to exit the mesh.

   

  • Mesh flow near cutouts and at edge will specify mesh quality. Now meshing is done. It’s time to check the quality of the mesh.
  2. Quality Check 2D
  • Click on Tools- Check Elements or F10 on keyboard. It will show the quality criteria (Min Length= 2, Max Length= 7) which we have specified according to requirements.
  • For this case we have to reduce the Min Length, Max Length Failing elements to zero. So we get good conversions into 3D
  • So the quality index will show the failing elements or worst elements in the meshing. We have to avoid these elements during meshing. We can overcome these elements by remeshing certain areas again which is a good way to do it.
  • Click on F12 and select the elements. Select the element from the outer edge to remesh the surface.
  • Make a square to remeshing. It will easy to remesh targeted area. This is way to get remesh all the surface again and again. Repaeting this procedure you will refine mesh.
  • Now again we can check for the quality criteria. These tools also help to get rid off from bad mesh.
  • Apart from these entire tools smooth tool is used for very minor adjustments in the elements to complete quality criteria.
  • After doing all this you will get a quality mesh which will pass all the quality criteria. In industry point of view the tolerance is given for quality criteria’s it may be in 5% to 10%.
  3. 3D Mesh conversion

  Now 2D quality passing elements we are going to convert into3D mesh. Here trias into Tetras. Click on 3D and go to tetramesh and  click on drop down menu to select the element and hit on mesh.

  2. 3D mesh Panel- Tetramesh

  a.Volume TetraMesh

   

  In 3D mesh panel select the volume tetra mesh. We can change the parameters for tetramesh. Go to tetramesh parameters. Change the required criteria’s according to requirements.  Select the displayed solid on dropdown menu. Hit on Mesh.

   

   

  1. Quality Check 3D
  • Here we are going to check the tet collapse in 3d mesh.
  • We are specifying tet collapse = 0.1%.

   

  • Tet collapse Cover

   

   

   

   

   

   

   

   

   

   

   

  Conclusion:

  1. Geometry cleanup manually (Defeature) make the geometry easy to mesh.

   

  2. For 3D meshing we have 3 different ways:

   

  1. 2D tria meshing and convert that to 3D tetra Mesh
  2. 3D mesh Panel- Tetramesh
  3. Volume TetraMesh
  4. For crude and fast mesh- quick tetramesh

   

  3. Elements violating threshold are zero. So the quality of mesh is good. And we can decide good mesh quality based on the mesh flow as well. So below figure shows the good mesh flow. So we can conclude the meshing is of good quality.