Challenge

Week 4

AIM:-

PROCEDURE:-

1) IMPORTING THE CAD MODEL:-

Open the ANSA software and import the cad geometry by clicking on File>Open>Browse the file from the list. Click OK.

As you can see the geometry is not in a good shape and it is hard to understand the geometry.
We can give the Length Parameter as 1 for the better visualization and to refine the model for our workability by going to Mesh Module, under Parameter tab click on Length. Give Length as 1.
Perform the topo function to arrange the faces and geometry of the model by selecting the Topo Module>Faces>topo. then make a box selection over our geometry .

2)GEOMETRY CLEANUP:-

After doing the topo, we can do the Geometry Check, by clicking on the Checks tool on Tools toolbar.
From the window appearing, check in the check list as our requirement, it include options like Unchecked faces, Collapsed Cons, Triple Cons, Needle Faces etc. Click on EXECUTE.

The errors appered can be eliminated by Auto Fix, If the auto fix can't eliminate the error we should do it manualy.
After clearing all the errors again do the Check.
IF the window shows 100% with a green strip then your geometry is ready.

3)MID-SURFACE GENERATION:-

One of the difficult part to mid surface in the bottle cap is the J shaped feature.
In order to mid surface it. We use the CURVE>MIDDLE option and form curve in the middle.
Then we use the SURFACE>EXTRUDE>GLIDE option to make a surface with the curves.
After that using INTERSECT connect the nearest mid surface and the feature
The next part is the teeth feature.
Here we will make middle curve in 2 sides and project the con to the bottom middle surface and make it a curve using Cons2curve.
Then we can make the middle by FACES>NEW>COONS.
Connrect it to the nearest midsurface using intersect.

These both features can be rotated as it is same and symmetrically placed.
For that we use COG and by selecting 2 circles in different heights we get 2 center points.
These centre points at differet heights act as an axis about which we will rotate the features.
Then go to TRANSFORM>COPY>ROTATE.
Give number of steps as, N-1.
If N is the total number of feature, we reduce 1 because ,already we have one.
For angle, ANGLE= 360/N.
Click inside the X box and select a point also select dx box and select the other point. Click OK, then finish.

For all other parts we can use the OFFSET or Mid.SURFACE option to for a mid surface.

4) Meshing:-

Before starting the meashing we should set the quality criteria. For that select Utilities tab and select Quality Criteria or F11. Set the criteria as our requirements.

Our Required Quality Criteria:-

Before starting the meshing process we need to select the delete in Hotpoints in Topo module. to delete the unwanted hotpoints and go to mesh module , select Length under perimeter tab in Mesh Module and give the target length.
For meshing a part we can use the Best option in the Mesh Generation tab. Click on Best, chose the face to mesh, middle click
After meshing for getting a good quality mesh we can use the Reconsturction or smooth in the shell Mesh tab
The quality of the mesh depends on number of rotating quads, trias and errors present. Reduce maximum number of trias , eliminate all rotating quads and errors
Most of the opposite trias can be eliminated using Split and Swap in Element tab, also by using Paste option in Grid tab

After the meshing , the elimination of errors is done and the off elements reduced to minimum and unmeshed elements are zero. We can now assign the thickness to the parts by double clicking on each parts property and giving the original thickness of the parent geometry.

5) LEARNING OUTCOMES:-

I learned about different tools in ANSA.
Learned to make mid surface of simple and complex parts. Especially Threads in this challenge.
Learned to mesh a geometry.
Learned use different tools more like Curve Middle, Cons2Curve, On COG,Rotating features
By doing the bottle cap I have learned how to eliminate errors and trias in different situations by using reconstruct, smooth, split, swap and paste.

6) CONCLUSION:-

All the geometrical errors are rectified.The part was meshed and it is having 98.57% of quads and 1.43% of trias.

Ship work like this
in your own course.