Week - 4 - 2D meshing for Plastic components

Aim:

To create a mid-surface & shell mesh of the given component by using given quality criteria and draw shell as solid (set PID). To create a product without fail by help of ANSA.

ANSA V119.1.4

Given data:

• CAD model - 2D meshing for Plastic components.
• Quality criteria – with the help of achieve the quality.

GIVEN DATA / INPUT

S.NO	QUALITY CRITERIA	VALUE
1.	Target/Avg length	1
2.	Min. length	.5
3.	Max. length	3
4.	Aspect ratio	3
5.	Warpage	15
6.	Skewness	45
7.	Jacobian	0.7
8.	Min. quad angle	45
9.	Max. quad angle	135
10.	Min. Tria angle	30
11.	Max. Tria angle	120
12.	Tria percentage	15

Steps to follow in ANSA.

• Import cad geometry.

Go to file > Open > Browse the location of the given CAD model > Select it click on Enter.

• Geometry cleanup.

Go to Toolbar > checks > Geometry > Visible > Execute > Check for the green tick beside geometry > close the window.

• Mid surface / Mesh generation.

For manual offset: In Topo module > Faces tab > click offset for manual skin generation & select faces and do middle click.

For auto mesh (auto mid surface generation): In Topo module > Faces tab > click mid surface > automatic middle-surface mesh generator.

• Shell or solid meshing:

Mesh parameter > Enter target length, Min. target length & Max. target length.

Measure the perimeter length - GO to perimeter > Length.

• Element quality check.

Click quality criteria / press F11 (shortcut key), apply the given input value.

• Mesh improvement: To improve the mesh, the result will be better.
• Apply load & Boundary condition: It depends on the requirements we need.

• Export input file: Export the result.

Procedure:

Import the cad geometry:

Go to file > Open > Browse the location of the CAD model > Select it click on Enter.

The given cad model is sheet metal – BOTTLE CAP is PLASTIC COMPONENTS.

Geometry cleanup:

Go to Toolbar > checks > Geometry > Visible > Execute > Check for the green tick beside geometry > close the window.

Execute to run the geometry cleanup. If there are any geometry errors, right click on the mouse on the highlighted errors and select auto-fix (automatically edit geometry issue) or edit manual as your wish.

Mid surface:

Before the mid surface we can check the model thickness by help of measurement option and decide whether the mid surface is necessary or not. If the model thickness is larger, casting or molding model is not need mid surface. Any complex shape we will manual create the mid-surface because complex shape cannot achieve fully in auto mid surface.

For measurement: Go to measure > Nodes > click on any two hot points to get the value

For manual offset: In Topo module > Faces tab > click offset for manual skin generation & select faces and do middle click.

There are so many options used to achieve the mid-surface, it fully depends on the way of thinking.

Step1: To measure the thickness of the part by help of measurement option.

Step2: We know the thickness, we offset the face by the help of a mid-surface option on the face tab.

Step3: After mid-surface check the mid-plain, it generates properly or not. If it is not proper, we can check and solve the problem by help of modules and create the face.

Step4: If there is any complex shape, we will project the cone onto the face and easily create the mid-surface by help of a project or curve option.

Step5: If there is a similar shape in the same structure without changes in dimension, we will copy the shape by the help of a transform option.

NOTE: In this given model, it is too small and has a complex shape and also a plastic component, so we do manual mid-surface.

Quality criteria:

Click quality criteria / press F11 (shortcut key) to open quality criteria window.

Apply the given input and save the Quality criteria value.

Shell meshing:

Mesh parameter > Enter target length, Min. target length & Max. target length.

Measure the perimeter length - GO to perimeter > Length

New window open > select perimeter > select the entire mid surface geometry

New tab is open > enter the value > ok

The perimeter is like a hot point. The hot point is increased. We can easily split the mid surface. Split the mid surface and mesh the mid surface separately, it helps to get a better result.

Meshing: Go to Mesh generation > best > select the surfaces to be meshed & middle click the mouse to confirm

Now the mesh is generated automatically in a selected area. After finishing the mesh, check the quality of the mesh. To hide mode from shadow mode, it shows clearly and there are any errors we need to fix by help of the shell mesh tab (Reconstructs, smooth option), elements tab (split, join, swap option), grids tab (Move & paste option).

If the mesh fails in quality criteria, we will re-generate the mesh with the help of shell mesh topo. The shell mesh topos have options to increase the quality of the model with the help of smooth, improve, reconstruct, split, join, cut options.

Colored elements are faied in quality. After fixed the quality.

Turn on the hidden option: Activate or de-activate the hidden drawing style.(Elements which exceed the selected quality citeria threshold valve, will be colored according.)

NOTE: Mid surface of component should be correct, Mesh flow should be Good, no rotating quads and Opposite trias should present in the model. Trias near to free edge or holes or on the fillets should be eliminated.

Draw shell as solid:

Draw shell as solid is used to convert the mid surface as a solid and check the PID as assigned or not.

For Draw shell as solid: Go to Quality criteria (short cut key - F11) > presentation parameters > Select Draw shell as solid > click OK

FINAL RESULT IN ANSA

For PID: Go to topo module > Faces > Set PID > Faces/shells (In selection window) > select the mid surface geometry > Now property window will open & the PID will be created for the mid surface.

LEARNING OUTCOMES:

To increase the performance at mid-surface, now I am able to achieve mid-surface in a complex sheet metal.

To increase the mesh quality with the help of mesh module tools, now I am able to work with tool flow.

Now I am easily Identify the quality error and resolve the error.

In the end of the challenge, I learn lot of commands and shortcut key.

CONCLUSION:

Geometry cleanup, mid surface extraction, and shell meshing of the given model were successfully done. And all the elements pass the quality criteria. All the features in the model are captured properly with good mesh flow. Tria concentration is kept low.