Stateczność sprężysto-plastycznej trójwarstwowej powłoki w kształcie wycinka stożka w ujęciu geometrycznie nieliniowym

In the paper the upper and lower critical loads are investigated, and also stability loss is analysed for an open sandwich conical shell loaded by longitudinal forces and uniformly distributed external pressure. It is assumed that the shell faces are elastic or plastic in the moment of buckling, and the core remains elastic. The problem is solved by the Ritz method. The equations are derived on the basis of deformation theory of plasticity using the concept of the growing load (Shanley). An iterative algorithm of calculation has been elaborated, which make it possible to analyse the shells in elastic, elastic-plastic or in totally plastic prebuckling state of stresses. The numerical examples show the influence of principal geometrical and physical shell's parameters on the stability loss at large deflections.