Analysis of Circular and Non-Circular Rings with a Varying Distributed Load
Louis Gerhardus Dunn, Dunn, Louis Gerhardus (Creator)
A rather extensive treatment of the stresses in fuselage main bulkheads is given in NACA Technical Report No. 509. The Least work equations developed in the report are for the most general case. The examples given are for concentrated loads, which are in balance, and applied. at various points on a circular bulkhead.
Now the shear loads which are transmitted by the skin and stiffeners to a main ring exist in the form of a distributed load which varies around the bulkhead.
The purpose of· this paper is to present an analysis pf a main bulkhead in which the wing reactions a.re balanced by a varying distributed load around the bulkhead. The shear distribution although not exact because of the interaction of skin and stiffeners, seems however, closer to the actual existing conditions than would be a case in which the shear loads are treated as concentrated loads.
To somewhat simplify the energy equations the bending and torsional shears were treated separately, the work due to the shear and axial load deformations were also neglected. The error introduced is relatively small.
In the particular airplane to which this solution was applied 80% of the fuselage cross section area consisted of skin and the remaining 20% consisted of stiffeners. Hence the shear transferred by the skin is of major importance.
The case chosen as an illustrative example is an unsymmetrical condition since this is the most general case.
Thesis, Dissertation, English, 1936