A Review of Effective Plating for Use in the Analysis of Stiffened Plating in Bending and Compression

Abstract

The review is divided into three main parts. The first is very brief and covers shear lag effects associated with stiffener plate bending. Part 2 concerns the behavior of unstiffened long plate elements (a ≥ b) in compression, which is referred to as effective ‘width’ effects. The concepts considered are maximum plate strength and how this is affected by initial distortion, normal pressure, and boundary conditions; stress distribution in plate elements before failure; and the "reduced effective width" concept for defining plate element stiffness, as required for use in stiffened-plate collapse theories. Final appraisal leads to recommendations based upon the equation advanced ten years ago for mean expected stress-free plate strength: σm/σο = (2/β) — (1/β2). It is used by the British Navy and has been recommended in Europe for box-girder bridge design. Part 3 concerns welding stress effects, and a critical strain theory is advanced for describing welded plate behavior in compression. The review has of course assessed appropriate test data, including a reappraisal from three full-scale destroyer tests. Some emphasis has been placed upon the statistical characteristics of the data, in order that this may help establish structural strength distributions for probabilistic approaches to ductile structural reliability. The paper ends with a brief historical review drawn from aeronautical, civil engineering and naval architectural sources, and a listing of the more important effective width formulas.