Determination of the stress distribution in reinforced monocoque structures Part III A theory of swept wings where the ribs are in the line of flight

Abstract

This paper gives and applies a method of estimating the stresses caused by root constraint in a two-spar swept wing of reinforced monocoque construction where the ribs are parallel to the line of flight. The general scheme of the analysis develops the fundamental equations that govern the stresses, strains and displacements in the separate components~ Then, by comparison of displacements along their inter-sections, equations of compatibility are formed. The solution of these equations yields the stress distribution and the distorted shape. In deriving the fundamental equations for the skin-stringer combination, use is made of an oblique system of co-ordinates and stresses. A suggested numerical procedure is given for the evaluation of the stress distribution and distorted shape. It is found convenient to use matrices and the procedure has been so planned that the elements of a matrix are obtained by simple operations on the dements of preceding matrices. A wing loading condition is also derived which produces zero rib warping, i.e., there is no redistribution of stress at the root of the wing. Tests on a cellulose-nitrate model have provided good qualitative confirmation of the theory.