Stressed‐Skin Structures: New Formulae for Calculating the Stability of a Monocoque in Compression

Abstract

ONE of the outstanding problems in design of stressed‐skin structures is that of ensuring adequate rigidity to guard against instability failure or buckling of the parts of the structure which have to carry compressive loads. Such structures consist usually of a scries of longitudinal members or stringers with intersecting transverses or frames. Apart from the waving of the skin itself in the panels thus formed, which must usually be tolerated and which remains modcrate in extent so long as the stiffening members themselves do not deflect, and docs not impair the ability of the structure as a whole to continue to take increasing load, there are two possible forms of buckling. The stringers alone may bow between adjacent frames, which remain fixed, or longer waves involving both stringers and frames may occur. The strength to resist the first type of failure can be estimated with reasonable accuracy by treating the stringers as struts of length equal to the frame spacing, and gives a design criterion for the stringers. It is fairly evident that for this rather elementary treatment of the stability problem to be adequate it is necessary that the frames themselves should have a certain minimum rigidity. It is in determining this minimum rigidity that the question arises of the possibility of the second type of buckling, which will be specially considered here. Whether this will, in any practical case, be sufficient to fix the size of frame required, cannot of course be stated in general terms, as this will depend on the local loads which the various frames may have to carry. Fig. 1 shows the type of deformation involved, for the special case of the side of a monocoque fuselage, which may be subjected to compression due to lateral bending under the action of rudder and inertia loads. The mode of waving is specified by the longitudinal wave‐length (two frame spaces in the illustration) and by the transverse wave length, which may be the full width of the panel or something less than this.

Citation

Lockwood Taylor, J. (1935), "Stressed‐Skin Structures: New Formulae for Calculating the Stability of a Monocoque in Compression", Aircraft Engineering and Aerospace Technology, Vol. 7 No. 12, pp. 314-315. https://doi.org/10.1108/eb029997