Week 3 - 2D meshing for Sheet metal
AIM:
For the given Hood model, Take the mid surface for all the components after checking the geometrical errors and mesh the mid surface with the given element Quality Criteria.
GIVEN:
No. Quality Criteria Value
1 Target/Average Length 5
2 Minimum Length 2
3 Maximum Length 7
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
12 Tria Percentage 15
OBJECTIVE:
The objective of this challenge is to perform the geometric cleanup and extract the mid surface of the components of given hood model and then mesh this components following the given Quality Criteria.
PROCEDURE:
- Firstly import the hood model in ANSA software and open it following the given steps:
In toolbar, go to file > open > select the file >ok
- After opening the model, one should perform topo cleanup to prevent geometrical errors. For that go to the topo option on right hand side of toolbar and go to faces> topo and select the whole model and hit the middle mouse button. This way topo cleanup is carried out.
- After that geometry check is performed by going to the checks > Geometry and selecting all the parameters, geometry check is executed as shown in below image:
These errors were fixed by right click on them and choose fix option.
- Now select each part one by one for meshing and follow the steps given below:
1) Go to the model browser and select the parts one by one for meshing. The given hood model contains four parts having different thicknesses as follows:
- Inner panel- 0.75 mm
- Outer panel-0.75 mm
- Hinge Reinforcement- 1.2 mm
- Latch Reinforcement- 1.2 mm
2) Extract the mid surface of the part using offset option. Choose the offset option in faces and select all the surfaces. Then after checking direction of arrow, give half of the thickness value as offset value and offset the surface. Then assign separate PIDs for midsurfaces of all the components. The thickness is assign by going to the List > Properties > New
3) After midsurface is generated for each of the component , assign the mesh parameters by going to the Utilities>Quality Criteria- Presentation Parameters and enter the given quality criteria and apply. (this quality criteria can be saved for future reference).
4) Now go to the mesh module and assign element length by going to the Perimeters > Length >target element size. Enter the target length for all the components as 5.
5) Then divide the surface into small sections using Macros> Cut so that better mesh flow is generated.
6) Now meshing is done using Mesh Generation> Best. This tool generates best possible mesh flow for the surface.
7) Then refined the mesh by using Shell Mesh> Reconstruct. Make sure that there are no rotating quads and opposite trias present in the model. Reduce trias near to free edge or holes or on the fillets. OFF elements must be zero after giving quality criteria.
8) After meshing, smooth option is used to get good quality mesh flow.
LEARNING OUTCOMES:
1) Performing this challenge enables to use different tools in the software.
2) Learning of both the options for extracting midsurface.
3) Knowing how to use different tools to get good quality mesh.
CONCLUSION:
After performing proper geometrical cleanup, extraction of midsurfaces for each component and assign thickness to each of them, the given hood model is meshed according to the given quality criteria.