Week 4 - 2D Meshing for Sheet Metal

Aim: For the given CCB CAD model, Check for Geometry cleanup, Take the midsurface, and mesh it with the below 2D element Quality Criteria.

S.No	Quality Criteria	Value
1	Target/Average length	5
2	Minimum Length	3
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
10	Tria Percentage	15

Objective:

1. To check the geometrical errors in the CCB CAD model.
2. To check the CAD Topology and CAD Clean Up.
3. To extract the Mid surface for all components of the CCB CAD model and assign thickness to the mid surface.
4. To achive mention qualitiy criteria and features of the model have to be captured properly with good mesh flow.
5. To mesh the each mid surface for better mesh flow.
6. To write a detailed report on manual mid surfacing methed.
7. To mention the result which gives a best mesh flow of the CCB CAD model.

Procedure: 1. Topology Cleanup

The first time to import the CAD model in the ANSA preprocessor then the model shows in two colour ,gery for posiive and yellow for negative direction for offset it is used for orientation of model in ENT mode. Toppology means how elements are bounded and connected to each other.We check compitability of grafics card for ANSA means hot points and cons visible or not when moving the model in ENT mode.CONS are of three types single ,double and triple. Single cons means that cons which share only one surface,double cons are that cons which share two surface,triple cons are that which share three surface.Triple cons is a type of geometrical errors beacause it shares three surface which cause geometry incompitency in the model so it is required to remove from geometry for topology cleanup.some times small entites can be cause a problem if we have small face with sharp edge then surface may be failed for quality criteria therefore check our CAD model for every small entities remove before create a mesh for correct and efficient setup of our simulation required right topology.when we check the geomety then we find out single,triple cons and autofix with a single click of mouse and apply topo for to connect the surface ,also increase the cons resolution to know actual gemetry of model.

2.Midsurface Generation: After geometry clean up of CCB CAD model then we go to create a midsurface for meshing.First of all we measure the tjhickness of the component at different part of model, if the thickness of the component is uniform or constant through out the model so that it is a sheet ,metal or thickness is varrying then it is a plastic component.Midsurface means conversion of 3D model into 2D to know the volume of the component.we generate the surface between two surface is known as mid surface.In this model we extract the mid surface with the automatic midsurface generation is used because this model has a different thickness component so here we assign a same PID for same thickness. 3. PID Allocation: After midsurface generation we create a same PID for same thicknes of component because it has very large no of component.PID means property ID , property ID of component is defined by material and thickness of the component of the model. 4.Meshing: After creating a midsurface we go for geometry checks of midsurface and assign a PID for midsurface hence our model is ready for meshing .Before meshing we set up Mesh parameter and Quality criteria Which provided for specific model.Mesh is a network that formed of cells and points.It can have any shape and anyused to solve by partial diffrential equation .Each cell of mesh represents an individual solution for entire mesh.in FEA allowed us for mixed type of mesh ,cell and unstructured meshing.General in meshing we used best mesh and mixed type TRIA and QUARD element for meshing.After creating a mesh shows a good mesh flow if mesh have some issue then we go for mesh improvements we have many tools and rules for creatingand improve the mesh. 5.Result: 1.We mesh the given CCB CAD Model and assign PID to the each component of the model and result shows good mesh flow within the given quality criteria. 2.The model achive the given mesh parameter and quality criteria which given in model. 6.Conclusion: For the given CCB CAD model check geometry cleanup and find out midsurface,mesh the midsurface with in given quality criteria for good mesh flow.