Meshing of plastic component of the Vehicle Floor panel | HyperMesh

AIM : To mesh the plastic component of the vehicle Floor panel model as shown below with the given quality criteria.

Quality Criteria –

Target Element Length = 5 mm

PROCEDURE :

At first we will open Hypermesh and choose our User Profile as RADIOSS. Then we will import the model using Import Tab. After importing the model in Hypermesh, we can see 21 components in the component tree. Among these components, Back_wheel_Panel_Body_0 component has the main body and some of the remaining components have small different parts of the main body. So we will move all the parts in a separate single component which will result in easier and better midsurfacing. To perform this, we will create a new component and rename it as Back_Wheel_Panel_Body. Then we will go to Organize panel in Tool page and we will select all the surfaces to be moved and then we will click on Move option. So all the surfaces are in a single component and we will delete all the other components.

Here we are going to manually midsurface the component. Before performing midsurfacing we will make sure that the topology and geometry of the model is perfect for midsurfacing. If there are any surface defects, we will remove those defects using suitable commands from Quick edit panel to obtain better cleanup of geometry of the model. Then we will start with midsurfacing. In order to store the midsurface of the component, we will create a new model named as Back_wheel_Panel_Body_Midsurface and make it as current component.

Then we will measure the distance between inner and outer surface by pressing F4 and navigating to distance panel. The measured distance is 0.75 mm. We will go to Offset subpanel under Surface edit and select all the outer surfaces which we will offset inwards for specified distance of 0.375 mm. Now to mesh the surfaces, we will have to perform the geometry cleanup on the component to clean up the model geometry which may contain free edges, merged edges or surfaces, missing surfaces or missing surface continuity, etc.

In Geometry Cleanup, we will use toggle edge option, split surf-node option and replace point, add/remove point, add point on line options, etc. to obtain the better topology for meshing. In the model there are some small semi-spheres which may cause difficulty in meshing. So we will delete these semi-spheres using delete surf command in Quick edit panel and then we will fill these holes using filler surf command and then toggle them using toggle edge command to obtain a plane surface as shown below,

Some areas have too many unnecessary topological lines, so we will toggle all these lines. We will create surfaces using ruled surface command in areas where surfaces are missing or deleted. Some connecting areas have very small distance and we can easily predict the failure of elements is such areas shown below,

In such cases we have two options, either we can toggle the edges and split the surface from a certain location where elements won’t fail or we can mesh the particular area and connect the elements using replace node command in such a way that the elements won’t fail. So we are going to use the second option.

MIDSURFACING RESULT :

Now we will proceed for meshing. We will mesh the component with given quality criteria in Automesh panel in 2D page or by pressing F12 shortcut key. To reduce the number of Trias generated in the mesh, we will keep remeshing the elements. This method is generally carried away when there are a lot of Trias or opposite facing Trias as we want the model to have more Quad and less Tria elements as the orientation is better in Quads. Now we will check the quality index of the meshed elements under Quality Index panel in 2D. If any elements fail in worst quality, we will optimize the elements using Cleanup Tools. Then we will check for the specified quality criteria. The elements failing the given quality will be optimized in similar way using Cleanup Tools. To obtain better mesh flow and connectivity, we will use Align, Project and Replace node commands as well. As specified earlier, the elements failing in small topological areas are optimized using replace node command as follows,

At the end we will have to specify the thickness to the elements as per the parent model geometry. As we measured earlier, the thickness throughout the geometry is 0.75 mm. So we will create a new Property in the Model panel, rename it as Thickness_0.75mm and specify its thickness as 0.75 mm. Then we will assign this property to Back_wheel_Panel_Body_Midsurface component. At last, to make sure that there are no free edges between the elements, we will check the edges in edges panel under Tool page. If there are any free edges, we will connect the elements using equivalence command or replace node command. To check whether the elements have proper thickness assigned to them, we will view the elements in 2D Detailed Element Representation format. Thus our model is ready.

Meshing Result :

CONCLUSION : The Floor panel model is meshed based on the given quality criteria. There are no discontinuities or free edges between the elements and almost every element is passing the given quality criteria.