Week 2 Challenge : Surface meshing on a Pressure valve

SURFACE MESHING ON A PRESSURE VALVE

Aim:

To create a surface meshing on the surface of a pressure valve model using ANSA.

Objective:

To create a surface meshing on the surface of a Pressure valve model using ANSA, for three differeent mesh target length of 5 mm, 3 mm and 1 mm and element type as Triangle (Tria)

Introduction:

ANSA is a comprehensive CAE pre-processing software for finite element analysis that delivers all of the flexibility needed for complete model build up, from CAD data to solver input file, in a single unified environment.

Mesh generation is the process of defining continuous geometric forms such as 3D models by employing 1D, 2D, and 3D mesh face shapes by means of discretization. The finer the mesh, the more precisely the 3D model is specified.

A surface mesh is a collection of polygonal faces, commonly triangle (Tria)ngles, that collectively create the object's surface covering. A surface mesh has the benefit of being quick to produce and useful for visualisation.

Steps:

• Import the CAD geometry
• Clean up the geometry by TOPO deck
• Apply the mesh conditions using Mesh deck
• Generate the Surface Mesh

Procedure:

• Open the CAD geometry by importing the CAD model file which having the extension of .ansa which can bee seen in Fig.1.

Figure 1

• As we can see there are many openings in surface of pressure valve, it will give geometry error as we can see in Fig. 2. So, we have to patch or fill the missing surfaces by using tools like cut, fill hole in TOPO deck.

Figure 2

• From Fig.3, we can see the missing surfaces were been created by using tools like cut, fill hole in TOPO deck.

Figure 3

• Now the model was ready for next step of enclosing the geometry surfaces. In Fig.4, it was evident that all the open ports were closed as well by using tools like cut, fill hole in TOPO deck. So, now the model was closed completely.

Figure 4

• Small faces on the surface in Fig. 5 will results in low quality of mesh. So, small faces on the surface of geometry has to be removed by tool called cut in TOPO deck in order to get high quality of mesh.

Figure 5

• Before going for meshing, assign the PID region for the common set of surfaces based on the different bodies in a component. PID regions has been assigned which can be seen in Fig. 6

Figure 6

• After assigning PID region, check for the geometry for any existing error before going to meshing. Geometry check has been done which can be seen in Fig.7, which shows the Triple Cons error, but all the times Triple Cons error was not an actual error. So, moving the geometry further from TOPO Deck to MESH Deck for meshing.

Figure 7

• Set the mesh length as 5 mm using length tool. Set perimeters and macros length as 5mm and in mesh parameter set the mesh element into triangle (Tria) which can be seen in Fig.8.

Figure 8

• Then in mesh generation tab using spot mesh tool create the triangle angular (Tria) mesh on the surface of a cylinder. From the Fig. 9, we can see that the surface of the cylinder was meshed and the meshs were in triangle angular (Tria) element and there is no quads element which can be evident in the details panel which is located in the side bottom of the interface.

Figure 9

• Length of the mesh was 5 mm which can be evident in Fig. 10.

Figure 10

• Similarly, set the mesh length as 3mm using length tool. Set perimeters and macros length as 3mm and in mesh parameter set the mesh element into triangle (Tria) which can be seen in Fig.11.

Figure 11

• Similarly, set the mesh length as 1mm using length tool. Set perimeters and macros length as 1mm and in mesh parameter set the mesh element into triangle (Tria) which can be seen in Fig.12.

Figure 12

Learning outcome:

I learnt how to fix geometry and surface mesh flaws in a pressure valve model, as well as how to remedy mesh errors and how to correct such mistakes.

Conclusion:

Surface mesh had been done on the pressure valve model by doing the TOPO clean-up with no geometry error having a mesh length of 5mm, 3mm and 1mm and mesh element of triangle (Tria) which yields a number of mesh elements of 8762, 24829 and 212415 respectively.