Week 3 - 2D meshing for sheet metal

AIM

The main objective of this challenge is given car hood is meshed in ANSA and checked for the quality parameters assigned to it .The geometry is captured perfectly to deliver a good mesh and that will give more accurate resluts during the analysis part.

2D shell mesh

The 2D mesh module is used to construct two dimensional finite element meshes. The mesh consists of nodes that are grouped together to form elements. In 2D meshing there are some element types involved to decide what type of analysis to be done on the model they are

Tria Element

The cell shape consists of 3 sides and is one of the simplest types of mesh. A traingular surface mesh is always quick and easy to create it is most common in unstructred grids

Quadrilateral Element

This cell shape is a basic 4 sides one. It is most common in structured grids .Quadrilateral elements are usually excluded from being or becoming concave.

MODEL

The given input modle is car hood .There are steps to achieve the quality mesh in the model

• Cleaning geometry
• Extracting midsurface
• Meshing
• Quality checking
• Assinging thickness

Cleaning Geometry

The check manger used to say all the errors in the model and listed it in the window accoding to the list input cleanup parameters .Then the module is cleaned with the unwanted surfaces using tools

The hotpoints tab is used to make changed in the points presents in the construction and the feature line of the model. The cons tab is used for adding or removing the lines in the model .The faces option is used to create or delete the surface in the model

MIDSURFACE

To simplify the meshing the solid part is supposed to take a midsurface .The purpose of the middle surface to reduce the expenses of analysing the whole solid part and also it easy for the meshing .

There are two ways to extract a midsurface manual and automatic method . Based on the model structure the method is selected.

OUTER INNER

LATCH HINGE

MESHING

After the middle surface extaraction the geometry of the model is checking again for the error. Then the meshing is done through the command For the whole modification of the mesh present in the surface mesh edit options improve reconstruct are used.

OUTER INNER

LATCH HINGE

QUALITY CHECKING

The quality checking is the most important step in the meshing .It helps in the analysis part to finish the analysis faster .The element quality is checked through hidden option

OUTER INNER

LATCH HINGE

THICKNESS

Each and every time the ANSA itself again a thickness to the newly created component.

The allowable percentage of tria elements in the model is about 15% and the tria elements present in model is 1.42%

Conclusion

The midsurface of the component is obtained and meshing is performed .Quality of the mesh passes the given quality criteria

Outcome

• Learnt to perform geometry cleaning
• Generating midsurface throught auto and manual method
• Mesh generation Eliminating failed mesh and smoothing