scope:

Introduction

This document describes two different, but equally acceptable methods, for buckling and ultimate strength assessment of plated structures.

The first method, as given in Part 1, is a conventional buckling code for stiffened and unstiffened panels of steel. It is an update and development of the stiffened flat plate part of previous DNV Classification Note No. 30.1 "Buckling Strength Analysis". Recommendations are given for plates, stiffeners and girders.

The second method, as given in Part 2, is a computerised semi-analytical model called PULS (Panel Ultimate Limit State). It is based on a recognized non-linear plate theory, Rayleigh-Ritz discretizations of deflections and a numerical procedure for solving the equilibrium equations. The method is essentially geometrically non-linear with stress control in critical positions along plate edges and plate stiffener junction lines for handling material plasticity. The procedure provides estimates of the ultimate buckling capacity to be used in extreme load design (ULS philosophy). The buckling limit is also assessed as it may be of interest in problems related to functional requirements, i.e. for load conditions and structural parts in which elastic buckling and thereby large elastic displacements are not acceptable (SLS philosophy). The PULS code is supported by official stand alone DNV Software programs. It is also implemented as a postprocessor in other DNV programs.