Week 4

Aim:

To Check for the geometrical errors and to mesh considering the given quality criterias.

Procedure :-

• Import the BottleCap.IGS file into ANSA.
• Geometry cleanup of the model.
• Create and Extract of Mid Surface.
• Assignmnet of thickness.
• Defeaturing.
• Meshing.

Given Quality Criterias:-

S.No	Quality Criteria	Value
1	Target/Average length	1
2	Minimum Length	.5
3	Maximum Length	3
4	Aspect	3
5	Warpage	15
6	Skewness	45
7	Jacobian	0.7
8	Minimum Quad Angle	45
9	Maximum Quad Angle	135
10	Minimum Tria Angle	30
11	Maximum Tria Angle	120
10	Tria Percentage	15

Step 1 :-

Geometry check:

Import the Bottle Cap into ANSA and set proper orientation and change the perimeter length value to 1 .

MESH>PERIMETER>LENGTH.

Fig 1.1

Step - 2:-

Geometry Cleanup :

• Check for all the geometry errors in the checks manager in the Task Bar as shown in figure 2.1.

CHECKS>GEOMETRY>EXECUTE

• Eliminate all the Triple Cons and Cracks by Auto fix or manually as shown in figure 2.2 .

Fig 2.1

Fig 2.2

Step - 3:-

Developing and Extraction of Mid Surface:

• Manual Mid Surface has to be taken rather than auto mid as the component is having varying thickness which will create quality issues.

Manual Mid surfacing can be taken using 2 methods:-

1) Offset Command :- In this command we need to select the faces for which we need to take out the Mid Surface and further assign offset value. i.e. thickness of the surface/ 2 as shown in figure 3.1.

TOPO MODE>FACES>OFFSET.

2) Middle Command:- In this command we need to select the 2 faces for which the mid surface has to be taken and on confirmation it will automatically generate the required mid surface of that feature as shown in figure 3.2. This command does not require any assignment of offset value.

TOPO MODE>FACES>MIDDLE.

Fig 3.1

Fig 3.2

Step- 4:-

Assigning thickness and setting property ID :

• After extraction of mid surface, new property ID for the component needs to be assigned.
• To set property ID, go SET PID command.

TOPO MODE >FACES>SET PID

• Box select the portion for which the new PID has to be assigned. On confirmation of the command, the property tab will popup on the screen. On right click of the popup menu, go to NEW>PSHELL, the new propety card will be displayed.
• Enter the required data and set the thickness by referring into the parent geometry.
• New PID has been created and thickness is assigned to the selected faces as shown in figure 4.1.

Fig 4.1

Step - 5:-

Defeaturing :

• In this process, we need to remove the unwanted cons that will disturb the mesh flow.
• This has to be done as the distance between some of the cons are less than minimum length, that can cause a quality error after meshing. Hence, unwanted cons, Edges and fillets has to be eleminated using the appropriate command as shown in figure 5.1.

TOPO MODE>FACES>CUT.

Fig 5.1

Step - 6:-

Meshing:-

• Change the visualisation from TOPO MODE to MESH MODE.
• Enter the required mesh parameters and quality criteria as per the instructions, which has been shown in the figure 6.1.

UTILITIES>MESH PARAMETERS

UTILITIES>QUALITY CRITERIA.

• Mesh the given component using the different MESH GENERATION options such as BEST or BATCH

MESH GENERATION>BEST/ BATCH>SELECT.

• Use RECONSTRUCT or SMOOTH command, if the meshed surface requires any changes in the mesh flow.

MESH MODE>SHELL MESH>RECONSTRUCT.

MESH MODE>SHELL MESH>SMOOTH.

• Now remove or move the trias in different directions using SPLIT, SWAP and PASTE command as per the necessity of a good mesh flow.

MESH MODE>ELEMENTS>SPLIT

MESH MODE>ELEMENTS>SWAP

MESH MODE>GRIDS>PASTE.

• Basically, avoid rotating quads by using the appropriate commands.
• After meshing, all the quality criterias of the components must be satisfied.
• Now, change the visualisation of the mid surfaces to solid shell by switching on the DRAW as SOLID command as shown in figure 6.3.

UTILIITIES>QUALITY PARAMETERS>PRESENTATION PARAMETERS>DRAW SHELL AS SOLID.

• Thus, the mashing has been completed for the given component.

Fig 6.1

Fig 6.2

Fig 6.3

Learning Outcomes:

• To fix geometrical errors and to cleanup the geometry of the model.
• To create and extract the mid surface from the parent geometry of a plastic component.
• Defeaturing of the unneccessary cons and hot points.
• Meshing the component taking into account all the required quality criterias.
• To elliminate trias and rotating quads.

Conclusion:

• From this challenge we can conclude that different surfaces of the same components have different thickness and therefore seperate PIDs has to set for different surfaces with reference to their thickness.
• The mesh generated meets all the given quality criteria and thus this model can be given for solver process.

Google drive sharable link:

https://drive.google.com/file/d/1mrkLe6yv1yuyPfBWLoQ5BhcPB3l9fKo0/view?usp=sharing