Week - 5 - 2D meshing for Plastic components

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	1
2	Minimum Length	0.5
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

 Objective:                                                                                                                                                                                                 

1. To check the geometrical errors in the BOTTLE CAP model.
2. To check the CAD Topology and CAD Clean Up.    
3. To extract the Mid surface for all components of the BOTTLE CAP 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 BOTTLE CAP 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 cleanup or Topology cleanup then we go for create a  midsurface for meshing. FIirst of all we measure the thickness of the CAD model at diffrent part of the model if thickness is uniform through out the model so it is a sheet metal component or the thicness is less than 6mm or thickness is varrying then it is a plastic component. Midsurface means the conversion of 3d model into 2d or create a surface between two surfaces.There are diffrent metod of  create midsurface. 
1.Manual Midsurface Generation 2. Automatic Midsurface Generation 3.Semi Automatic Midsurface Generation                                                                                                        3. 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.                                                                                                                                                                                                                                                                                                                                                4.PID Alocation:                                                                                                                                                                                            PID means property ID Or part ID is defined by material and thicknessfor specific part of a model e.Every property is defined by material. Weceate a new PID for a specific part of a model for diffrent thickness and materals so PID is depend upon MID means Material ID is defined by some specific property like E(MODULUS OF ELASTICITY),G(MODULUS OF RIGIDITY) ,NU(POISSIONS RATIO), RHO( Density of Material ), Thickness of Material.                                                                                                                                                                                                                                                                                                                 5.Result:                                                                                                                                                                                                         We achive the target mesh parameter and quality criteria we have some off elements which failing for quality criteria due to triple cons . mesh flow is good.                                                  6.Conclusion:                                                                                                                                                                                             For given BOTTLE CAP model we extract the mid surface and mesh for given mesh parameter and quality criteria for good mesh flow.