Fem determination of the plastic limit load for cylindrical shells

In this paper a new approach to the consistent identification of the deformation pattern vital for the precise determination of the plastic limit load of a cylindrical shell from MNA when using modified Southwell (MS) and Tangent Stiffness (TS) plots is presented. It is proposed that the formalised assessment of the plastic collapse load can be done by the application of the relation between the load factor increment Δr_R and the arc length s – for an identification of achievement of the complete plastic collapse mechanism from MNA, and then the MS or TS plot for the displacement pattern that corresponds to the identified plastic mechanism.