Stability of ribbed cylindrical shell under local edge loads

We examine a hinged cylindrical shell (l, r, h are the length, radius, wall thickness) that is regularly stiffened by stringers (k is the number of stringers; F, I, I^t are the cross-section area and the moments of inertia in bending and torsion) and frames (K₁ is the number of frames; I₁, I₁^t are the moments of inertia in bending in the plane of the ring and in torsion). Compatibility of the deformation of the skin and the ribs is satisfied with respect to deflections and angles of rotation, the eccentricity of the placement of the ribs relative to the middle surface of the skin and the discreteness of arrangement of the stiffeners are not considered. To the edge of the shells there are applied cyclically K₂ local axial loads, which are represented in the form of uniformly distributed normal stresses P₂ on elementary regions (areas) of arc length b. The shell is additionally loaded by an axial force that is applied in the form of uniformly distributed over the end normal stresses P, and also by internal pressure of intensity q, applied to the side surface. The stability problem is solved in the linear formulation for the moment-free precritical state; the energy method in the Timoshenko form is used.S. P. Timoshenko Institute of Mechanics of the Ukraine Academy of Sciences, Kiev. Translated from Prikladnaya Mekhanika, Vol. 30, No. 1, pp. 45–50, 1994.