When it comes to hexahedral meshing a sphere in ANSYS, there are two main approaches:
Mapping approach, which involves accurately controlling the number of boundary segments and using mapping to divide the sphere into hexahedral elements.
Sweeping approach, which involves cutting the sphere and creating hexahedral elements by sweeping through the sphere.
Here is a step-by-step guide on how to use each approach:
1. Create a sphere. In this example, we use a sphere with a diameter of 100 and Solid185 element type.
2. Cut the sphere into eighths by dividing it horizontally and vertically and removing the remaining sections.
3. Define the mesh size and use mapping to divide the sphere into hexahedral elements.
4. Switch to cylindrical coordinates and copy the meshed eighths four times, including the mesh, then use symmetry to complete the sphere.
5. Select all and merge the coincident nodes, then renumber them using the following APDL commands:
1. Start by creating a regular hexahedral structure inside the sphere.
2. Subtract the sphere from the hexahedral structure and remove the auxiliary structure, leaving a sphere with a hexahedral cavity.
3. Project one of the hexahedral faces onto the sphere by rotating the work plane and cutting along the X-Y and Y-Z planes.
4.Adjust the transparency and select the one-sixth of the sphere to keep, while deleting the rest. This section will be numbered 16.
5. Switch to cylindrical coordinates and rotate and copy the section four times.
6. Define a local coordinate system (11) as a cylindrical coordinate system, rotate the section 16 along the Y-axis by 90 degrees, and copy it along the positive and negative direction (90 degrees) to create the final meshed sphere.
7. Switch back to Cartesian coordinates, create a hexahedral structure inside the sphere, and perform a Boolean bonding operation on the whole mesh.
8. Select all and define the element size before sweeping the mesh to complete the hexahedral meshing process.