Meshing of Plastic Bottle cap using ANSA Pre-processor for Structural Analysis

Aim : Meshing of Bottle cap using ANSA pre-processor.

Objectives :

For the given component (Bottle cap), checking for the geometrical errors and meshing with the given element Quality criteria. After meshing the component the thickness has to be assigned.

1) To clean up the topological errors.

2) To clean the geometry using different set of tools.

3) Running diagnostic check.

4) Use of Boolean operations for better visuality of the geometry.

5) Create mid-surface depending on the type of geometry.

6) Assigning length and meshing the whole geometry.

7) Compressing the geometry after rectifying all the errors in it.

Quality Criteria :

Mesh parameters :

Procedure :

1) Cleaning up the geometry by identifying the geometrical and topological errors listed under the check manager such as single cons, triple cons, unchecked faces, Collapsed cons, Needle faces, Overlap faces, Cracks and penetration errors which should be avoided to proceed further, if we clean up most of the geometry there will be least possibility in error while meshing.

2) Mid-surfacing depends on the type of geometry, if the thickness is varying across the geometry then manual mid-surface extraction method should be used. For example for the picture shown below the thickness of that particular part is 0.5032mm, we achieve this using measuring tool to get the distance from node to node.

3) After this, selecting the each of the two surfaces by giving the offset value, since we want middle surface it is written in half of the measured value which is 0.5032/2 and negative sign because the vector is in opposite direction to that of the surface. We can we do this by this method for other surfaces as well in the given geometry to acquire mid-surface for it.

4) Unlike offset method, we need not measure the thickness of a particular part, by just selecting the surfaces will extract the mid surface. This option is only useful when the two surfaces are of same shape or identical surface on each side.

5)Extend tool under \'Faces\' option in the \'TOPO\' module is used to connect the the single midsurface parts which are left hanging are pasted to the base geometry to achieve proper midsurface of the whole geometry.

6) After extracting mid surface for each part, we have to assign thickness in the property id menu where different properties can be assigned to that particular part. Here, since we have varying thickness throughout the geometry, thickness will be different for each part. Thickness is given as \'T\' in the Properties menu.

7) Meshing of the geometry is done by using \'Best\' mesh option under \'Mesh Generation\'. What best mesh option does is, it reads the information given in the mesh parameters and the quality criteria to give the best possible results which are significant to the meshing of geometry.

8) The desired mesh quality is achieved by elminating the OFF elements which do not fit under the quality criteria.

Learning outcome :

For above geometry auto-midsurface option did\'nt provide significant results beacause it did\'nt captured the geometry well due to which a manual approach should be considered while working with geometry of varying thickness.

Conclusion :

Mid-surfacing of the component is achieved using different types of manual midsurfacing method and the given mesh quality was met using different options under Element option in \'MESH\' module.