Creating Mid surface, geometry cleanup, meshing and quality checking on Back Door model by using HYPERMESH
AIM :
To create manual midsurface from given back door component, preprocessing on it and all created elements should satisfied the given element parameters.
OBJECTIVES :
1) Geometry cleanup on a parent components.
2) Extracting a manual midsurface by using Offset sub panel in each components from parent component.
3) Geometry cleanup on a midsurface as per convenience for meshing.
4) To Checking the element qualities as per given element criteria.
CAD MODEL IMAGE :
1) Open a Hyperworks software and set the user profile which depends on components gets deformation. If a deformation is small, we gonna to perform a "Optistruct" user profile which is implicit solver and if a deformation is large, we gonna to perform a "RADIOSS" user profile which is explicit solver.
2) Click the "Import Solver Deck" option from where tool bar section, then select the "Import Gemetry" option and select the file type which is "IGES" because our given model file type is same. Click the folder option and select the respective file which will going to perform and then click the "Import option" it showing up the components from graphical window.
3) After importing the model, by default "Auto" geometry color mode had selected. For visualizing the topologies, manually change into "By Topo" mode for viewing the "Free edges, Sharped edges, T Junction edge and Supressed edge" from components.
4) Make sure delete the solids from imported model by using delete option. In this model, there is no solid parts are present.
5) In this back door model consists of three different components and different cross section also.
6) In each component, there's some geometrical issue, make sure resolved that error before generating the manual midsurface.
i) Inner Panel :
This component had not been exactly in symmetrical in shape, there's few some changes from both side. So we need to generate the midsurface throughout the entire component from surface face.
ii) Upper Body :
This Upper body component is exactly symmetrical in shape about the Y axis. So,we need to generate the midsurface any one of the side or else generate throughout the entire component from surface face.
iii) Lower Body :
This lower body is also exact symmetrical in shape at which about Y axis. Similarly, we need to create a midsurface either one of the side or else generate throughout the entire component from surface face.
PROCEDURE TO ATTAINING THE OBJECTIVES :
i) Geometry Cleanup for Parent Component :
1) First of all, delete the unwanted components from given model such as points and unassociated surfaces. As we know the topology edges which are Free edge, T sharped edge, Sharped edge and Supressed edge. Following this, we can finding the geometry error.
2) If the surface has not any equivalence at edge, it represents by red color. If the surface has equivalence to two surfaces, it represents by green color. If the surface has equivalence with three or more surfaces to each other, it represents by Yellow color. If the line has blue in color, it's called supressed edge line.
Lower Body :
1) In this component, a free edges were shown due to adjacent surfaces has not connecting properly to each other. By resolving those error, we can use " Toggle option" under the "Quick Edit" panel with increasing the tolerances value to filling the gaps between them.
2) If it's not working, then manually creating the sharped edge on both side as per convenience, by using surface delete option to delete the surfaces near the edge. After that, by using filler option to create the new surface.
3) After geometry cleanup, a component looks like below snap.
Upper Body :
1) In this case also some surface equivalence has missing at which hemming region, we need to toggling with higher tolarence value at where area of inconnectivity region.
2) A Upper body is a symmetrical in shape about an middle line, a geometrical error happens only on left side and right side there's no geometrical error. So, using right side surface to extracting the manual mid surface by using offset sub panel under which surface edit panel and then surface reflecting on another side.
3) Another side there's no geometrical error, so we need to extracting the manual mid surface.
ii) Extracting the middle surface :
1) After completion of geometry cleanup on parent component then we gonna extracting the manual middle surface.
2) If we generating the automatic midsurface by using "Auto midsurface" panel under the "geometry" main menu panel, it seems some geometrical errors happening on it.
3) Instead we generating the manual middle surface by using "Offset" option under where "Surface edit" panel. This process is following to all components in the given back door model.
4) Procedure for generating the middle surface is simple and its same for all the components.
Procedure for Extracting Manual Midsurface :
1) Select the "Surface Edit" panel under which "Geometry Main Menu" Panel and then click the "Offset" Sub panel.
2) Before going to extract the mid surface, make sure check the appropriate thickness of the respective component.
3) Create a new component for saving the extracted midsurface from respective parent component in separately.
4) Selecting the respective component surface and then right click on "SURF" and select the "by face" option to auto select the entire face on the respective component.
5) If we try to extracting the midsurface without creating an duplicate, it causing to distortion of parent component. Make sure create a duplicate surface from selected face by using "duplicate" option at when right click on a "SURF" bar and also select the current component for saving.
6) A midsurface means middle surface between two surfaces, as we know the thickness of the component. Put the offset distance is half of original thickness of that particular component.
7) Before executing into offset, make sure conform the vector direction of midsurface from parent component, if it's required.
8) Finally, execute the offset option to extract the middle surface between them. This process is called Extracting Manual Midsurface.
I) Middle Surface for Inner component :
1) Inner component thickness is 0.75 mm, so we need to generate the surface at place which middle of the component and offset distance is half of a inner component thickness which distance is 0.375 mm.
2) Just select one of the surface at anywhere from which inner component and then automatically select the surfaces by using "the face" option under which right click on" SURF" selector bar.
3) After selecting the appropriate surfaces, it will looks like same as below image.
4) After execute the "Offset" option, a middle surface is created between two surfaces. A middle surface is looks like same as below image.
II) Middle surface for Upper component :
1) A Parent Upper component thickness is 0.75 mm, so we need to generate the surface at place which middle of the component and offset distance is half of a upper component thickness which distance is 0.375 mm.
2) Just select one of the surface at anywhere from which upper component and then automatically select the surfaces by using "the face" option under which right click on" SURF" selector bar.
3) After selecting the appropriate surfaces, it will looks like same as below image.
4) After execute the "Offset" option, a middle surface is created between two surfaces. A middle surface is looks like same as below image.
III) Middle surface for Lower component :
1) A Parent Lower component thickness is 0.75 mm, so we need to generate the surface at place which middle of the component and offset distance is half of a lower component thickness which distance is 0.375 mm.
2) Just select one of the surface at anywhere from which upper component and then automatically select the surfaces by using "the face" option under which right click on" SURF" selector bar.
3) After selecting the appropriate surfaces, it will looks like same as below image.
4) After execute the "Offset" option, a middle surface is created between two surfaces. A middle surface is looks like same as below image.
iii) Geometry Cleanup for midsurface :
This geometry cleanup is help us to capturing the proper flow mesh with low tria concentration and also elements are comes under the given element criteria range.
I) Inner component :
1) If two neighbour lines distance are below 3mm, it's necessary to supressing anyone of the line because it failing due to minimum element criteria.
2) Additionally, to create a new sharped edge line, if a surface has converge or diverge area. If creating a more lines, mesh capturing very properly and neatly. After cleanuping, inner component looks like below image.
3) At hemming portion, a corner sharped edges are suppressed by using "Toggle" option under the "Quick Edit" Panel.
II) Upper Component :
1) After extracting the midsurface, we need to create a new sharped edge lines and also supressing some lines for capturing a proper flow mesh. If a two line points lateral distance is falling under minimum element criteria we should go to supressing any one of the line.
2) Also supressing the corner edge lines and create a new mid lines for capturing the mesh at where hemming portion.
3) After cleanup the geometry, a component looks like below snap.
III) Lower Component :
1) Supressing the two corner lines and create a new lines at where hemming surface for capturing the proper mesh flow and also restrict to element failing due to minimum element criteria.
2) Choose anyone of the side from lower body component, create a sharped edge lines between the surface for capturing the better mesh flow.
iv) Generating the mesh :
1) To subdividing the respective component with infinitesimal control volume, that framework is called meshing. This process is called discritization.
2) Click "Auto mesh" panel under the "2D" main menu panel, change into surface selection mode instead of element selection mode. Select the surface and perform meshing operation on it, Repetitively to do the meshing operation whenever gets the proper flow mesh.
I) Meshing for Inner Component :
1) Before going to perform an meshing operation, make set the current component as "Middle surface for inner body". A inner body is symmetrical in shape except some few area, create a mesh on half a portion and reflecting the elements except unsymmetrical regions
2) There's no elements are failing due to minimum element size, because of we had cleanuped on that hemming areas.
3) We have reflect those elements from which one side to another side except some few regions. Click the "Reflect" option under which "Tools" option, select the elements which are needed to reflect and create a duplicate elements to current component and then select the appropriated base node or point for reflecting about an symmetrical line or axis.
4) After reflection, we have to perform meshing operation on unsymmetrical region.
5) For finding free edges by using "Edges" panel under the "Tools" main menu panel and equivalence with nodes.
4) After completion of reflection and equivalence process, a mesh will look like below image.
II) Meshing the Upper Component :
1) Disselect the all component except upper body for which generating the mesh on a surface. Set the current component which is "Middle surface for upper body".
2) Perform meshing operation on a surfaces untill complete the half a portion.
3) This component is exactly at symmetrical in shape, so it's simply reflecting the element into another side by using just "reflect" option.
4) After reflection process, a free edge lines are created due to unequivalence of the elements. Select the elements which are presented by near the free edge line to proceeding equivalence with nodes.
5) After reflection and equivalence process, a meshed elements are showing like below snap.
III) Meshing for Lower Component :
1) Disselect the all component except lower body for which generating the mesh on a surface. Set the current component which is "Middle surface for lower body".
2) Perform meshing operation on a surfaces untill complete the half a portion.
3) Similarly, to do the same procedure to create the mesh on entire surface.
iv) Quality Checking :
Before perform anything, make sure assigning the element parameters by using "Criteria Editor" through which "Preferences and criteria file settings".
Inner Body :
A inner body element qualities are satisfied the all element quality parameters.
Upper Body :
A Upper body element qualities are satisfied the all element quality parameters.
Lower Body :
A Lower body element qualities are satisfied the all element quality parameters.
Back Door components :
All components element qualities are satisfied the given element parameters.
CONCLUSION :
Successfully completed the process of extracting mid surface, geometry cleanup on a mid surface and then checked the element quality with different element parameters on given Hood body.
Inner component :
Upper Component :
Lower Component :
All Components :
