Thin-shell structures are light weight constructions using shell elements. These elements are typically curved and are assembled to large structures. Typical applications are fuselages of aeroplanes, boat hulls and roof structures in some buildings.
A thin shell is defined as a shell with a thickness which is small compared to its other dimensions and in which deformations are not large compared to thickness. A primary difference between a shell structure and a plate structure is that, in the unstressed state, the shell structure has curvature as opposed to the plates structure which is flat. Membrane action in a shell is primarily caused by in-plane forces (plane stress), though there may be secondary forces resulting from flexural deformations. Where a flat plate acts similar to a beam with bending and shear stresses, shells are analogous to a cable which resists loads through tensile stresses. Though the ideal thin shell must be capable of developing both tension and compression.[1]
The most popular types of thin-shell structures are:
concrete shell structures, often cast as a monolithic dome or stressed ribbon bridge or saddle roof
Lattice shell structures, also called gridshell structures, often in the form of a geodesic dome or a hyperboloid structure
membrane structures, which include fabric structures and other tensile structures, cable domes, and pneumatic structures.