Membrane and bending stresses in hulls
Instability of shells

A hull has two main characteristics:

• a thin wall ;

• is curved in at least one direction.

Steel shells are used as load-bearing elements in a wide range of structures: storage tanks, ships, towers, silos, submarines, offshore structures, missiles, water towers, chimney pipes, spaceships, etc.

• Tensile, compressive and shear stresses, parallel to the shell wall and constant over its thickness, are called "membrane stresses" (figure 1 c) and their resultants over the thickness are called "membrane forces".

  At any point on the shell, three membrane forces can be defined (figure 1...