A: shell start;

B: shell end;

Axis X: shell transverse axis;

Axis Y: shell transverse axis;

angle θ of nozzle insertion is taken from this axis toward axis X;

Axis Z: shell longitudinal axis.

All axis can be horizontal and vertical according to the shell options:

Points A, B.

All calculations by the finite element method (FEM) fix both ends.

Inner overpressure.

Outer pressure.

Hydrostatic pressure.

Thermal strains.

Specifies the offset of point B relative to point A (in the plane of the local X and Y axes).

Defining taper by the wall slope angle or the second diameter.