STABILITY OF CILINDRICAL SHELL, REINFORCED BY RIBS

V.V. Novozhilov suggested the approximate theory of cylindrical shells which are supported by often placed ribs. In this article the problem on stability of the shell under excessive external pressure is solved using the Novozhilov theory. It is also taken into account that parameters of curvature does not depend on tangential displacements. V.M. Darevskij showed that the theory is valid for medium length shells. The equation for bending round cylindrical shell which is supported by ribs is obtained. The article considers conditions of hinge edge. As a result of analysis we get a simple formula which is convenient for practical use to calculate upper critical pressure. The formula was got using two assumption: there is one half-wave along shell generatrix; the square of number of waves is much more than one. If we consider shell without ribs then the formula is consistent with well-known the A.S. Volmir formula for upper critical pressure which is given in the monograph on stability of deformable systems.