Week 8-Challenge

Link for Housing- https://1drv.ms/u/s!AlDYq9nTGAGCg1ytTvgw7GD4WqNq?e=DdJYjb

Link for CRANK HOUSINNG- https://1drv.ms/u/s!AlDYq9nTGAGCg1uHxjR3NVwN6s1Y?e=Vwkio5

Link for CHASSIS ASSEMBLY- https://1drv.ms/u/s!AlDYq9nTGAGCg12NNysUc23_3stv?e=Nsk8M7

Objective : To perform a Volume tetra mesh for the given components under specified quality criteria..

Procedure :

1.HOUSING COMPONENT:

• First import the model into the hypermesh by using the import option.
• Check the model in wireframe mode to check for the free edges and surface duplications. If any such free edges are duplications present remove those.
• In order to 3d Tetra mesh, we first need to make a 2D mesh with Tria elements.
• When meshing the housing, we need to organize the HUB part from it to a separate collector.
• QUALITY CRITERIA :

Elements sizes: Min- 2mm, Target- 5mm, Max- 7mm Tet collapse: 0.15

• Meshing

2D > auto mesh the entire component hub and housing separately with target element size as 5mm with respectively changing current component.

• Then go for 3D meshing. For that place the radio button in 3D mesh option and Go to Tetra mesh>tetra mesh parameters >change tet collapse to 0.15 >Tetra mesh>select the 2D mesh elements>Mesh to current component>mesh. This will give us the 3d tetra mesh of the 2D meshed component.
• Go to tools>Check elements>Place the radio button in 3D>click on tet collapse to find out the elements fails for tet collpase.Enter the value of tet collapse as 0.15 and check for failed elements.
• Tetra remesh feature can be used to repair the failed 3d tetra elements. To use that first Find the Failed elements for tet collapse. Go to tool>check elements>enter tet collapse value as 0.156>click on tet colapse>save failed>Go to mask option>select elements>retrieve>click unmask adjacent 2 to 3 times. Then we should go to Tetra remesh option in 3D mesh panel and select the displayed elements and click on remesh.
• Translate option can also be used to repair the failed elements.tet collapse is basically the height o the 3D tetra elements .So we need to increase the element height using translate node option by pressing F4.

2. CRANK HOUSINNG :

Geometry Cleanup:

• Import the TETRAMESH_PM.hm file to hypermesh.
• Clean up the geometry using toggle edges command.

MESHING

• 3D > tetra mesh > Volume tetra the elements with 6mm target length and min length as 2mm.
• Set Tetra mesh parameters tet collapse as 0.15.
• Tools > Check elements the Component for 3D > Tetcollapse. Save failed elements and mask.
• Unmask adjacent elements and Tetra remesh the elements.

3. CHASSIS ASSEMBLY

GEOMETRY CLEANUP:

• Import the chassis Assembly file to Hypermesh.
• Cleanup the surfaces of gear tooth that would be unnecessary for tetra mesh and fill it with plain surface using surface edit commands.

MESHING

• 3D > Volume tetra the elements after setting the tetramesh parameters for min length 2mm, max length 7mm and target size 6mm and tet collapse as 0.15.
• Tools > Check elements is used for checking tet collapse and tetra remesh is carried out with failed elements.
• Tools > Reflectis used to reflect the duplicated elements about y-axis.
• Chassis assembly is a symmetric component so mesh one half of the geometry and we can reflect the half mesh to the other side.For that afte meshing the one half of the geometry and check for failed elements and ensure there is no elements fails for tet collapse .Then go to tool>reflect select the displayed half mesh>choose axis for reflection>Choose base node>reflect.

NOTE: The reflected elements are deleted while saving to keep the node count below 100000 to save the file in student's version.

Results

• The Geometry cleanup is carried out for all the components.
• Meshed with tria elements and volume mesh is carried out.
• Tet collpse errors are fixed.

Conclusion:

• Method to 3D tetra mesh the 3d components in hypermesh is learned. And learned what is tet collapse and why it is important to avoid it in 3 D meshing.