Coordinate System

1- Axes

Axes and joint numbers of the shell element are shown in the figure

2- Direction and meaning of Shell element forces

M11, M22

Bending moments in 1 and 2 axes

M12

Planar torsion moment

V13, V23

Cutting forces perpendicular to the surface of the element

F11, F22

Tensile forces in the element plane in the direction of interest

F12

Element shear force