Chapter 23 – Wings

Publisher Summary Wing sections consist of thin skins stiffened by combinations of stringers, spar webs, and caps and ribs. The resulting structure frequently comprises one, two, or more cells and is highly redundant. However, the large number of closely spaced stringers allows the assumption of a constant shear flow in the skin among the adjacent stringers, so that a wing section may be analyzed as though it were completely idealized, as long as the direct stress carrying capacity of the skin is allowed for by additions to the existing stringer/boom areas. Bending moments at any section of a wing are usually produced by shear loads at other sections of the wing. The chordwise pressure distribution on an aerodynamic surface may be represented by shear loads (lift and drag loads) acting through the aerodynamic center, together with a pitching moment. This system of shear loads may be transferred to the shear center of the section in the form of shear loads, together with a torque. This chapter investigates the analysis of multi-cellular wing sections subjected to bending, torsional, and shear loads, although, initially, it is instructive to examine the special case of an idealized three-boom shell.