Divide Shell Elements

This is the refinement process, basically to meet FEA software restrictions (number of points, angles ).

The Divide Shell Elements option acts on all shell elements regardless of their origin. The word shell may cause confusion here as in the FE context it refers to all thin surfaces as opposed to beam and truss elements while in our products shell is related to the sculptured surface. So the FE model shell elements come from curved and planar plating and maybe also from profile webs depending on detail level.

Max no of Edges is the maximum number of edges that an area shall contain. In general four-sided elements are preferred especially when the model contains curved parts.

Max Face Warping Factor is the maximum edge height deviation divided by the square root of the area (see Unwarp shell elements).

Max Thickness Warping Factor is the maximum edge height deviation divided by the average element thickness (see Unwarp shell elements).

Min Line Length Factor means that, when you refine the FE geometry, the created lines will not be shorter than ["Min Line Length Factor" x element size].

Max Angle Deviation means that angles between two neighboring lines in an area should preferably be right angular plus or minus the Angle deviation.

The relation between the criteria is that if a shell element has more points than Max number of Edges an attempt is made so subdivide it. However in doing so it is made sure that lines shorter than Min Line Length Factor times the element size are not created and that angles sharper than a right angle minus Max Angle deviation are not created. The result may be that shell elements still have more points than Max number of Edges after the process.

Note: In ANSYS Mechanical APDL (ANSYS Classic), the maximum number of points in an area is 18.