Week 12:Project-1-Meshing of Door Inner Panel Challenge

AIM:

To extract the mid surface of given plastic component and mesh the component under given quality criteria and assign thickness.

OBJECTIVE:

1. To extract the mid surface and mesh it with proper mesh flow.
2. To ensure the mesh should pass the given Quality Criteria.
3. To assign thickness to all the components of the model

GIVEN:

Target Element Length = 4 Units

S.N	Quality Criteria	Value
1	Aspect Ratio	5
2	Skewness	45
3	Warping	15
4	Taper	0.5
5	Min. Length	2 Units
6	Max. Length	6 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	20
10	Max angle Tria	120
10	Tria %	10

The area which is having more than 6mm thickness should not model in 2D. You can capture them like in the Below-mentioned picture

The below image has some geometrical issue on it so modeling them in the 2D will be difficult.

In those areas, the main objective is to capture the hole so we can take a mid surface by creating a flat surface with a hole like an image below.

No need to model the below-mentioned area. The mentioned area does not have a proper attachment to the model.

For variable thickness areas, Assign the thickness taking an average value of the cross-section

SOFTWARE USED:

Hyper Works 2021

GIVEN MODEL:

GIVEN PLASTIC DOOR INNER PANEL

BRIEF PROCEDURE:

Step 1 : Import given model and Geometry clean up for given component.

Step 2 : Extraction mid surface using different options.

Step 3 : 2D mesh on extracted mid surface under given criteria.

Step 4 : Assign various thickness for each parts.

STEP -1 : IMPORT GIVEN MODEL AND GEOMETRY CLEAN UP

• Import the model by using IMPORT option.
• Visualize the model for find deformities in its surface or free edges,which can be visualized in wireframe mode and By Topo mode and repaired.
• Defeature all the surface fillets from Dog House,Ribs using following steps

Geom→Defeature→ Surf Fillets

By setting the minimum and maximum radius as 0.1 and 6. fillets are highlighted select all the Fillet surfaces which to be removed and hit remove.

FILLETS BEFORE REMOVE

FILLETS HIGHLETED

AFTER FILLET DEFEATURE SURFACE FILLETS

• Make sure about the surface errors before start to take mid surface.if you see unwanted free edges in the surface repair using correct step.
• BY TOPO mode you easily find the free edges

MODEL IN BY TOPO MODE

Step -2 : EXTRACTION OF MID SURFACE USING DIFFERENT OPTIONS

• Plastic components present in the cars are having different thickness.
• So took mid surface using automatic mid surface extraction is difficulty for plastic component.
• Automatic extraction does not provide satisfactory results hence we need to take mid surface manually by using offset(SHIFT+F9) option.

Geom→surface edit (offset)

• The manual mid surface is done by part by part so it consume little more time byt it comes good.
• For ribs we have another handy option name is final edit tools which is present in mid surface option.

Geom→mid surface (final edit tools)

• For Extracting mid-surface for DogHouse,create mid-surface through its circumference in a manner so that it will satisfy its objective.
• Important thing we need to notice that is ribs in the model which needs to connect to the base surface. For that follow one of the following step

Geom→Surface edit (extend) select surface to be extended > select base surface > extend

• In extend option different type of options available,use it as our requirements.
• After extend ensure the Yellow line should appear at the intersection of ribs and base surface.
• Remove all these issues before start meshing.

FINE MID SURFACE

• And also carried out several geometry edit for getting good mesh flow.we toggled unwanted topology lines which makes element failure.
• but always careful we never remove feature edges
• Now the mid surface is extracted properly as shown in figure.

Step -3 : 2D MESH ON EXTRACTED MID SURFACE UNDER GIVEN CRITERIA

• Before start mesh we need to set meshing Quality criteria by using preference menu

CRITERIA FILE SETTING

• Now we can start the 2D shell mesh for the component by using following steps

2D→automesh

• We mesh the mid surface by element size as 4 and mixed elements.
• First we should start from complex surface to get good mesh flow.
• While meshing we should maintain the tria percentage as low as possible.
• We can maintain trias in the direction of the mesh flow.
• We should avoid opposite trias.
• Use REBUILD option for getting better mesh.
• Split the surface before start meshing it gives good mesh and fine flow.

MESH FLOW ↓

• Try to make the mesh flow towards big end to small end, it gives good flow

OPPOSITE TRIAS

• These kind of opposite trias are acceptable on these region.

OVER ALL MESH AND FLOW

• While meshing the elements are fail because of criteria,that failure is cleared by using QUALITY INDEX.

2D→quality index

• But always careful with feature areas because it disturb everything.
• Try to clear all errors by using remesh,rebuild mesh.

QUALITY INDEX

STEP - 4 : ASSIGN VARIOUS THICKNESS FOR EACH PARTS

• First we need to create PROPERTY and MATERIAL before assign thickness.
• Right click on tab area and select create then component.now new component is created.
• Create as our need of different thickness of parts and organize the elements of parts based on thickness.

Tool→organize

COMPONENTS

• Now create property as same step followed for component creation.
• After creating property rename it and give material, thickness, card imeage,etc...
• This is must done for each different thickness.

PROPERTY

• Assign properties to each parts by following steps

Right click on component > assign > select property

• After assign see the difference to use 2D Detailed Element Representation .

2D Detailed Element Representation

• At the end one important step should check that is find free edges,

Tool→edges

• If find any edge that means there is no connectivity so make the connectivity by using following steps (F3)

2D→replace

FINAL MODEL:

FINALL MODEL

RESULT:

2D(Shell) mesh is done for given model under given criteria and thickness assigned succesfully using Hypermesh. Learned the meshing difference of sheet metak component and plastic component.