scholarly journals A parametric study on effects of pitting corrosion on stiffened panels’ ultimate strength

2020 ◽  
Vol 12 ◽  
pp. 699-710
Author(s):  
Liang Feng ◽  
Luocun Hu ◽  
Xuguang Chen ◽  
Hongda Shi
Keyword(s):  
Ultimate Strength ◽  
Pitting Corrosion ◽  
Parametric Study ◽  
Stiffened Panels

Ultimate Strength of Typical Stiffened Panels in Container Ships Under Localized Pitting Corrosion

2016 ◽  
Author(s):  
Jinju Cui ◽  
Deyu Wang ◽  
Ning Ma
Keyword(s):  
Life Cycle ◽  
Ultimate Strength ◽  
Pitting Corrosion ◽  
Load Capacity ◽  
Uniform Corrosion ◽  
Ship Structures ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Transverse Loads ◽  
Structural Capacity

In the life cycle of ships, corrosion exists and deteriorates ship structures, resulting in the degradation of ship structural capacity. Based on practical observations, non-uniform corrosion takes place instead of uniform corrosion which is adopted widely in design rules. So it is necessary to study the load capacity of ship structures under non-uniform corrosion. In this paper, the ultimate strength of typical bottom panels in container ships under localized pitting corrosion is studied by Nonlinear Finite Element Analysis (NFEA). The pitting corrosion is supposed to be of normally distributed circular shapes whose radius is in accordance with observational statistics. Different pitting corrosion densities with perforation in both the stiffener and panel plate are considered. Structural ultimate strengths under pitting corrosion are studied under longitudinal loads, transverse loads and combination of both, and the results are compared with that from equivalent uniform corrosion. Finally, the probabilistic characteristics of structural ultimate strength under pitting corrosion in life cycle are studied.

A parametric study on effects of pitting corrosion on steel plate's ultimate strength

2020 ◽  
Vol 95 ◽  
pp. 102026 ◽  
Author(s):  
Liang Feng ◽  
Jingke He ◽  
Luocun Hu ◽  
Hongda Shi ◽  
Changli Yu ◽  
...  
Keyword(s):  
Ultimate Strength ◽  
Pitting Corrosion ◽  
Parametric Study

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

Buckling and Ultimate Strength Assessment of FPSO Structures

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.

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

2007 ◽  
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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