A meshed model is of no use if the mesh quality is poor as it might give wrong results or not solve at all. Therefore element quality checks are necessary to ensure that the solver runs without any problem and gives proper results.
In this post, we are going to discuss the common quality checks performed for elements in Hypermesh and their significance.
We will start with the 2D elements and then go to the 3D elements.
Quality checks for 2D elements:
- Aspect ratio: It is the ratio of maximum edge length to minimum edge length.
2. Warpage: It is the angle between the normals of two planes formed by splitting the quad element along the diagonals. The maximum angle of the two possible angles is warpage. It signifies how much an element is out of plane.
3. Skew: Skew for quad is calculated by subtracting the minimum angle between the two lines joining the opposite mid-sides of the element from 90 degrees, while for triangular element it is obtained by subtracting the minimum angle between the lines from each node to the opposing mid-side and between the two adjacent mid-sides at each node of the element.
4. Jacobian: It signifies the deviation of the element from its ideal shape. It arises because of the transformation from a Global coordinate system to the local coordinate system.
Quality check for 3D elements:
- Tetra Collapse: Apart from the quality checks mentioned above for the 2D elements, Tetra collapse is the additional one available to check in 3D element quality check. Tet collapse is defined as the ratio of the height of the tetra element divided by base area of the tetra element.
The values for the above quality parameters can vary from industry to industry as well as from customer to customer. An experienced engineer would readily decide the value for these based on the expectations of the customer or the geometry. I have been using the default values for these checks.
You can also refer to the below video to see how to check element quality in Hypermesh
This is all for this post, see you all in the next post. Don’t forget to follow my Facebook and Instagram page for regular updates. Till then keep learning!