When using curved surfaces with features that use local axes, like plates, surface loads and surface contractions, in PLAXIS 3D2012.00, and such a curved surface is intersected with another curved or flat surface with local axes, the local axes for these curved plate elements on the intersecting edge with the other surface can be incorrect. This would lead to incorrectly defined local axes for the surface elements. Since the local axes are not correct, the results will be incorrect.
Common cases where this can go wrong are:
After mesh generation, review the mesh, select the plate elements and open this in a separate plot. Make sure that the local axes are activated in the View menu, and check if axis 1 (red axis) and axis 2 (green axis) are in the plane of the plate, and axis 3 (blue axis) is perpendicular to the plate’s surface.
The example below shows two tunnels that intersect each other:
Now let’s focus on the tunnel that is aligned with the y-axis:
When looking at the mesh plot for this tunnel’s plate elements, it cannot directly be seen whether the problem exists:
But after the model is slightly rotated, it can be seen that a number of local axes 1 (red) point inside the tunnel at the shared edge with the second tunnel:
In order to still use the model in PLAXIS 3D2012.00, there are two possible workarounds
This issue is fixed since PLAXIS 3D2012.01