Week 12 - Project-1

Objective : To generate the midsurface of the given components and mesh them according to the given quality criteria and assign them a thickness

Procedure :

Geometry Cleanup : First clean up the geometry of the given component, delete any duplicate surfaces, toggle unwanted edges.

The geometry is thereby separated into two components as shown and are named as comp_1 & comp_2 respectively.

Midsurface :

Next to generate the midsurface we select comp_1 and click on auto midsurface-->skin offset option.

By this option the basic geometry of comp_1 is captured. All the other surfaces have to be genrated manually using surface offset option in surface edit and entering the offset distance as half the thickness of the surface.

All the separately generated surfaces can be merged using the toggle edge option and increasing the tolerance values.

All the components like ribs need to have their midsurfaces generated separately from the parent geometry.

After this to match the surface of the ribs to the remaining midsurface we use line drag option in surfaces

After dragging the line beyond the mating surface we then trim using surfs.

After this a yellow line should appear at the interface of the rib and surface as shown below.

Toggle any unwanted edges as shown and then delete the unwanted surfaces on the other side to get the finished surfaces.

At multiple places doing the above trimming with surfs option will not work and will cause the geometry to get distorted due to non-uniform surfaces. As a result we need to draw cut lines to divide the surface as shown so that the distrortion is limited to a particular surface and the algorithm is able to trim the surfaces more efficiently.

We need to draw cut lines as shown, which will help aid in rib creation. We can draw the cut lines in quick edit panel and node-to-node option. The cut lines are drawn wherever required mostly wherever the ribs are present.

The lines can be suppressed later on at the time of meshing.

In this way using these methods, the midsurface is generated as shown below.

This is the midsurface for comp_1 & comp_2 respectively

Mesh generation :

Next we have to generate the 2d mesh of the midsurface and assign different thicknesses to all the components. The meshing is done for the midsurfaces and the ribbed surfaces simultaneously so that there is no mismatch in the nodes of these surfaces as shown.

All the ribbed components must be checked that their interface with the other surfaces have matching nodes as shwon. If they are not matching we can use tool-->edges-->preview equivalence and enter the tolerance value and equivalence them.

Any irreularities in the midsurfaces of any component can be recitified in the mesh

We can alter the direction of certain surfaces to match them up once they are meshed using the trranslate elems or nnodes option so that the surfaces are more uniform.

Separate surfaces can be meshed separately for ease in meshing as shown

We will try to reduce the number of trias elements by using remesh option and altering the number of nodes as shown to get the optimum quad elements.

We check that there are zero failing elements as shown below.

Assigning properties & thickness : Measure the thickness of all the sections of the parent geometry to assign the thickness. In this model there are around 6 different thicknesses required which will be assigned to different ribs, brackets, mounts etc as shown.

In the property section enter the thicknesses respectively and assign the properties to the different components. In this model the main midsurface is saved in comp1_main_ms. The parent geometry has been given grey colour

The midsurface of comp_2 is saved in two comps, they are comp2_ms_1mm and comp2_ms_6mm respectively.

All the surfaces that require different thicknesses have a separate component collector created as shown. In the end after we assign the thickness we can see if it has been applied successfully by selecting this option

Hence we have successfully assigned the thicknesses to all the meshed surfaces as shown.

Here we can see all the different thickness surfaces in different colour

This is how the mesh and thickness is assigned to comp_2.

Result :

Google Drive Link :

https://drive.google.com/file/d/1YvhauStBgsVZMXRO4wJ_NdYTl_fPQ6CG/view?usp=sharing

Conclusion : The method of performing 2d mesh and assigning component thickness is an accurate way of dicretizing a given component and capturing the geometry well.