Assignment 1-2D Meshing Challenge

Objective:

• To perform the geometry cleanup operation on the given files.
• To extract the mid surface of the model.
• To clean the mid surface of the model.
• To create a 2D mesh with a target length of 5mm having a minimum length of 3.5mm and a maximum length of 7mm.
• To assign proper thickness to the mesh by creating a generic property.

Procedure:

Part_1:

• We will first import the model in Hypermesh using the Import model browser option present in Tool Bar.
• After importing the model, we can see that there are some free edges and missing surfaces in the model.
• So we will need to perform the geometry clean-up on the model.
• Geometry cleanup is performed on the model to obtain refine geometry which outputs better results in midsurface and therefore the meshing of the component.
• To perform the geometry cleanup we will navigate to the quick edit panel by either pressing the F11 shortcut key or through the Geom page.
• In the quick edit panel, we will use the toggle edge option to toggle most of the free edge red lines to the shared edge green line.
• We will also use filler surf to fill any missing surfaces and replace the node option to replace and retain points to complete the geometry.
• After Geo cleaning the model will look like as shown below:

Midsurface:

• To obtain the mid surface of the model, we will navigate to a mid surface panel on the Geom page.
• Under extraction options, we will select offset+planes+sweeps, then we will select all the surfaces of the model in the auto extraction subpanel, and then we will click on the extract command.
• Hypermesh will perform auto mid surface and we will obtain the mid surface of the model.

Fillet removing:

• The fillets which are less than the minimum element length are removed using the defeature option.
• To defeature the fillet, Use the defeature option in the Geo page, and in that use the surface fillet option and select the fillet region that needs to remove.
• Similarly, all the fillet regions which are failing for the minimum element length are removed.

Midline creation:

• In order to capture the surface much better, the surface which is failing for the minimum element length is removed by taking Midline between.
• Using the midline, the surface is trimmed by using the surface edit option.
• After the surface is trimmed, the other two lines are toggled.

Mesh:

• In general, 2D meshing is performed for objects having a thickness of less than 6 mm.
• To perform 2D meshing on the model, we will navigate to the Automesh panel either by pressing the F12 shortcut key or through the 2D page.
• To mesh, we will select the surfaces one by one and create the mesh with target element size as 5 mm and mesh type as mixed.
• We will make sure that the holes are captured with an even number of nodes and there are fewer trias generated in the mesh.
• After completing the meshing of the model, we will check for quality criteria by pressing the F10 shortcut key or check elements panel on the Tool page.
• Here we will check for minimum length as 3.5 mm and maximum length as 7 mm criteria.
• If any elements are failing the quality criteria, we will optimize them by using cleanup tools and various commands such as combine, split, align, element optimize, smooth, project, replace node, etc.

Assign Thickness Value:

• To assign thickness to the elements as per the parent geometry thickness, we will create a new property.
• The thickness of the parent model is 0.91 and so enter the 0.91 as thickness in Property Entity Editor window.
• Now we will assign this property to the Middle surface component in the Model Browser by right-clicking on it and choosing the assign option.
• This will assign the thickness to the meshed elements.
• To view the thickened mesh, we will choose the 2D Detailed Element Representation in Toolbar.

Part-2:

Import model:

• We will first import the model in Hypermesh using the Import model browser option present in Tool Bar.
• After importing the model, we can see that there are some free edges and missing surfaces in the model.
• So we will need to perform the geometry clean-up on the model.
• Geometry cleanup is performed on the model to obtain refine geometry which outputs better results in mid surface and therefore the meshing of the component.
• To perform the geometry cleanup we will navigate to the quick edit panel by either pressing the F11 shortcut key or through the Geom page.
• In the quick edit panel, we will use the toggle edge option to toggle most of the free edge red lines to the shared edge green line.
• We will also use filler surf to fill any missing surfaces and replace the node option to replace and retain points to complete the geometry.
• After Geo cleaning the model will look like as shown below:

Skin offset:

• To obtain the mid surface of the model, we will navigate to a mid surface panel on the Geom page.
• Under extraction options, we will select Skin Offset, then we will select all the surfaces of the model in the auto extraction subpanel, and then we will click on the extract command.
• Hypermesh will perform auto mid surface and we will obtain the mid surface of the model.

Geo cleanup for proper mesh flow:

• The points which are close to each other are connected to a single line in order to achieve proper mesh.

Mesh:

• In general, 2D meshing is performed for objects having a thickness of less than 6 mm.
• To perform 2D meshing on the model, we will navigate to the Automesh panel either by pressing the F12 shortcut key or through the 2D page.
• To mesh, we will select the surfaces one by one and create the mesh with target element size as 5 mm and mesh type as mixed.
• One half has only meshed and it is reflected on the other side using reflect option.

Equivalence:

• After reflecting the elements on the other side, using the edges option in the tool page view.
• Using the equivalence option, equivalence the nodes which are having small gaps.

Mesh:

• Similarly, the other side also meshed one side and reflected another side.

Edge finding:

• After meshing all the surfaces, the free edge is found using the edges option in the tool page view.
• In case if any free edge is found within the surfaces, the points are pasted together to avoid any free edge.

Assign Thickness:

• To assign thickness to the elements as per the parent geometry thickness, we will create a new property.
• The thickness of the parent model is 2 and so enter the 2 as thickness in Property Entity Editor window.
• Now we will assign this property to the Middle surface component in the Model Browser by right-clicking on it and choosing the assign option.
• This will assign the thickness to the meshed elements.
• To view the thickened mesh, we will choose the 2D Detailed Element Representation in Toolbar.

Property card creation:

2-D Detailed View:

Part-3:

Import model:

• We will first import the model in Hypermesh using the Import model browser option present in Tool Bar.
• Since there are no free edges or any distortion surfaces in the model there is no need for geo clean.

MidSurface:

• To obtain the mid surface of the model, we will navigate to a mid surface panel on the Geom page.
• Under extraction options, we will select Skin Offset, then we will select all the surfaces of the model in the auto extraction subpanel, and then we will click on the extract command.
• Hypermesh will perform auto mid surface and we will obtain the mid surface of the model.

• After taking the mid surface, the geo clean is performed on the model in order to achieve the proper flow of mesh.

Mesh:

• In general, 2D meshing is performed for objects having a thickness of less than 6 mm.
• To perform 2D meshing on the model, we will navigate to the Automesh panel either by pressing the F12 shortcut key or through the 2D page.
• To mesh, we will select the surfaces one by one and create the mesh with target element size as 5 mm and mesh type as mixed.
• We will make sure that the holes are captured with an even number of nodes and there are fewer trias generated in the mesh.
• After completing the meshing of the model, we will check for quality criteria by pressing the F10 shortcut key or check elements panel on the Tool page.
• Here we will check for minimum length as 3.5 mm and maximum length as 7 mm criteria.
• If any elements are failing the quality criteria, we will optimize them by using cleanup tools and various commands such as combine, split, align, element optimize, smooth, project, replace node, etc.

Assign Thickness:

• To assign thickness to the elements as per the parent geometry thickness, we will create a new property.
• The thickness of the parent model is 1.8 and so enter the 1.8 as thickness in Property Entity Editor window.
• Now we will assign this property to the Middle surface component in the Model Browser by right-clicking on it and choosing the assign option.
• This will assign the thickness to the meshed elements.
• To view the thickened mesh, we will choose the 2D Detailed Element Representation in Toolbar.

Conclusion:

• The given model is imported into the hypermesh.
• The mid surface is taken using the auto mid surface option.
• The geo clean is performed on the model to achieve the proper mesh flow according to the given element criteria.
• Then, the thickness is assigned according to the thickness.