Learning Forum

[habibulaqil97]

Hello everyone.nCan anyone give basic guidelines on how to remove pyramids mesh elements? That is all from me. n

[Rob]

They're formed when you transition from a hex to a tet mesh. What's the problem with pyramids?n

[habibulaqil97]

Hello, sorry for late reply.nI was told by my supervisor that the elements generated should be anything but pyramids. n

[peteroznewman]

One problem with pyramid elements is older versions of MSC/NASTRAN doesn't have a pyramid element!n

[pdlagrosas]

LS-DYNA solver won't allow pyramids, too. How to properly eliminate them without affecting the problem's physics. Been trying for 2 months now but to no avail. Any attempt changes the behavior of the problem. Btw, I am solving a projectile-barrel in-bore process 

[Edna Lopez]

 

Hello, 

Here are some basic guidelines on how to remove pyramid mesh elements in ANSYS:

1. Identify pyramid elements: First, you need to identify the pyramid elements in your mesh. These elements typically have five nodes, with a quadrilateral base and a single apex node.

2. Check mesh quality criteria: Evaluate the quality of your mesh using criteria such as element distortion, aspect ratio, and skewness. High distortion or poor aspect ratios can indicate problematic elements, including pyramids.

3. Refine the mesh: If your mesh is coarse, consider refining it by adding more elements. Mesh refinement can help reduce the presence of pyramids and improve the overall mesh quality. Use mesh controls or adaptive meshing techniques to selectively refine the regions with pyramid elements.

4. Adjust element shape: Adjusting the shape of elements near the pyramids can help eliminate them. You can do this by manipulating the surrounding mesh, such as redistributing nodes or modifying element sizes and shapes.

5. Use mesh smoothing techniques: Apply mesh smoothing algorithms to improve the quality of your mesh and remove pyramids. Smoothing techniques can help redistribute node positions and minimize element distortion. ANSYS provides various mesh smoothing options, including Laplacian smoothing and spring smoothing.

6. Element renumbering: Renumbering the elements can sometimes help resolve pyramid-related issues. ANSYS provides tools to renumber elements based on different criteria, such as connectivity or proximity.

7. Mesh transition: Gradually transition from pyramid elements to other suitable element types, such as tetrahedrons or hexahedrons. This can be done by introducing transitional mesh layers, where the element types change gradually.

8. Verify the physics: After making changes to the mesh, it’s important to re-evaluate the physics of your simulation. Check if the modifications have altered the behavior of the problem or introduced any unintended effects. Adjust boundary conditions or other simulation parameters as needed.

 

 

[Edna Lopez]

Hope that my method is useful for you.

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