Ultimate strength assessment of plated steel structures with random pitting corrosion damage

<p>In Japan, many steel structures were constructed during the period of the high economic miracle, and they are now more than 50 years old and are aging. Corrosion has been confirmed at corners and the boundary of concrete-wrapped concrete in steel piers. It was found that corrosion damage at the corner of steel piers causes a decrease of seismic performance in our previous investigations that carried out seismic response analysis. Subsequently, in this study, the effect of corrosion damage at the near ground edge of steel bridge piers with a rectangular cross-section was investigated in detail on the buckling behaviour and seismic performance of structures. As a result, it is found that the buckling at the base causes a decrease in load bearing performance compared to the buckling in the entire panel. It is necessary to properly maintain to prevent buckling at the base caused by corrosion.</p>

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Buckling and Ultimate Strength Assessment of FPSO Structures

10.5957/smc-2005-d23 ◽

2005 ◽

Author(s):

Haihong Sun ◽

Xiaozhi Wang

Keyword(s):

Ultimate Strength ◽

Oil And Gas ◽

Element Analysis ◽

Strength Criteria ◽

Strength Assessment ◽

Stiffened Panels ◽

Oil And Gas Fields ◽

Extensive Test ◽

Offshore Oil And Gas ◽

Classification Society

Floating production, storage and offloading systems (FPSOs) have been widely used for the development of offshore oil and gas fields because of their attractive features. They are mostly ship- shaped, either converted from existing tankers or purposely built, and the hull structural scantling design for tankers may be applicable to FPSOs. However, FPSOs have their unique characteristics. FPSOs are sited at specific locations with a dynamic loading that is quite different from those arising from unrestricted service conditions. The structures are to be assessed to satisfy the requirements of all in-service and pre-service loading conditions. The fundamental aspects in the structural assessment of FPSOs are the buckling and ultimate strength behaviors of the plate panels, stiffened panels and hull girders. The focus of this paper is to address the buckling and ultimate strength criteria for FPSO structures. Various aspects of the criteria have been widely investigated, and the results of the design formulae proposed in this paper have been compared to a very extensive test database and numerical results from nonlinear finite element analysis and other available methods. The procedures presented in this paper are based on the outcomes of a series of classification society projects in the development of buckling and ultimate strength criteria and referred to the corresponding classification society publications.

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Visual Assessment of Corroded Condition of Plates With Pitting Corrosion Taking Into Account Residual Strength: In the Case of Webs of Hold Frames of Bulk Carriers

Volume 2: Structures, Safety and Reliability; Petroleum Technology Symposium ◽

10.1115/omae2007-29159 ◽

2007 ◽

Cited By ~ 1

Author(s):

Tatsuro Nakai ◽

Hisao Matsushita ◽

Norio Yamamoto

Keyword(s):

Ultimate Strength ◽

Pitting Corrosion ◽

Residual Strength ◽

Steel Plates ◽

Average Thickness ◽

Loading Conditions ◽

Equivalent Thickness ◽

Thickness Loss ◽

Minimum Cross Section ◽

Corrosion Pits

Corrosion pits with a conical shape are typically observed in hold frames in way of cargo holds of bulk carriers which carry coal and iron ore. The ratio of the diameter to the depth of the typical corrosion pits is in the range between 8–1 and 10–1 and its diameter might become up to 50mm. The evaluation of residual strength of members with large uneven pitting corrosion is difficult compared with that of members with general corrosion. Therefore, it is of crucial importance to develop a method for the evaluation of residual strength of pitted members. The purpose of the present study is to investigate the effect of pitting corrosion on the ultimate strength of steel plates under various loading conditions and explore a method for the evaluation of residual thickness of pitted plates. In the present study, a series of non-linear FE-analyses has been conducted with steel plates with a variety of random pit distributions under various loading conditions such as uni-axial compression, bi-axial compression, shear and combination of these. In these analyses, random pit distributions were calculated by the previously developed corrosion model. It has been shown that equivalent thickness loss, which is defined as thickness loss of uniformly corroded plates with the same ultimate strength as the randomly pitted plates, is smaller than or equal to 1.25 times the average thickness loss. It has been also revealed that the equivalent thickness loss for the ultimate strength under the above-mentioned loading conditions is smaller than average thickness loss at the minimum cross section, where the average thickness loss at the minimum cross section almost corresponds to the equivalent thickness loss for the tensile strength. Based on these findings, a method for the estimation of equivalent thickness loss of pitted plates has been discussed using the thickness diminution-DOP relationship, where DOP (Degree of Pitting Intensity) is defined as the ratio of the pitted surface area to the total surface area.

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Investigation of pitting corrosion damage of a hydraulic press trunk piston

Engineering Failure Analysis ◽

10.1016/s1350-6307(02)00041-9 ◽

2003 ◽

Vol 10 (2) ◽

pp. 251-254 ◽

Cited By ~ 1

Author(s):

Changli Wang ◽

Yuexian Cui ◽

Li Cui

Keyword(s):

Pitting Corrosion ◽

Corrosion Damage ◽

Hydraulic Press

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PHOTOGRAMMETRY MEASUREMENTS OF INITIAL IMPERFECTIONS FOR THE ULTIMATE STRENGTH ASSESSMENT OF PLATES

The International Journal of Maritime Engineering ◽

10.5750/ijme.v156ia4.937 ◽

2021 ◽

Vol 156 (A4) ◽

Author(s):

A Cubells ◽

Y Garbatov ◽

C Guedes Soares

Keyword(s):

Finite Element ◽

Ultimate Strength ◽

Compressive Load ◽

Initial Imperfection ◽

Maximum Load ◽

Surface Shape ◽

Element Analysis ◽

Strength Assessment ◽

Load Carrying ◽

Geometrical Imperfections

The objective of the present study is to develop a new approach to model the initial geometrical imperfections of ship plates by using Photogrammetry. Based on images, Photogrammetry is able to take measurements of the distortions of plates and to catch the dominant surface shape, including the deformations of the edges. Having this data, it is possible to generate faithful models of plate surface based on third order polynomial functions. Finally, the maximum load- carrying capacity of the plates is analysed by performing a nonlinear finite element analysis using a commercial finite element code. Three un-stiffened and four stiffened plates have been modelled and analysed. For each plate, two initial imperfection models have been generated one, based on photogrammetric measurements and the other, based on the trigonometric Fourier functions. Both models are subjected to the same uniaxial compressive load and boundary conditions in order to study the ultimate strength.

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