Ultimate Strength Formulations for Thin-Walled Structures with Localized/General Corrosion, Fatigue Cracking and Local Dent Damage
This paper is a summary of recent developments in the areas related to the ultimate strength limit state of aging steel plated structures, undertaken by the authors. As steel structures such as ships, offshore platforms and land-based structures age, they suffer structural degradation due to corrosion and fatigue cracking. They also suffer mechanical damage such as local dent and collision/grounding damage due to accidental loading or impact. To keep the structural integrity at a certain level, it is of vital importance to evaluate the residual load-carrying capacity and the potential risk of damaged structures as they age. The residual strength assessment is also essential to establish the cost-effective repair scheme of damaged structures. The present paper deals with the most profound topics on this issue; to develop the ultimate strength limit state design formulae for steel plate panels with structural damage. Localized/general corrosion, fatigue cracking and local dent typically found in aging marine structures are considered in this paper as types of damage. A series of buckling collapse tests and nonlinear finite element analyses were carried out in the present study on steel-plated structures with localized/general corrosion, fatigue cracking or local denting, with varying the type, size or location of damage as well as geometric and material properties of the test structures. By a regression analysis of both tested and computed results, ultimate strength design formulae are derived in closed-form. The insights and conclusions developed from the present study are summarized.