The Open Tube: A Study of Thin‐Walled Structures such as Interspar Wing Cut‐outs and Open‐section Stringers Available to Purchase

WE define as an open tube a thin‐walled structure, the cross‐section of which does not include any closed circuit. This property is common, for example, to the curved channel, the interspar wing cut‐out and the panel stiffened with Z‐sections, illustrated in FIG. 1 (a, b, c). But the interspar cut‐out with nose cell (FIG. 1d) is not an open tube in the present definition. All structures discussed in this paper are assumed to be cylindrical and to have a constant cross‐section. It is relatively simple to extend the results to conical taper and longitudinally varying thickness, but this would be beyond the scope and space of the present analysis (see, however, ref. 5).