Assessment of residual ultimate strength for wide dented stiffened panels subjected to compressive loads

2013 ◽  
Vol 49 ◽  
pp. 316-328 ◽  
Author(s):  
Ming Cai Xu ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Stiffened Panels ◽  
Compressive Loads

Ultimate Strength of Dented Narrow Stiffened Panels Subjected to Compressive Loads

2012 ◽  
Author(s):  
Mingcai Xu ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Compressive Load ◽  
Tensile Tests ◽  
Nonlinear Fem ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Geometry Model ◽  
The Finite Element Analysis ◽  
Compressive Loads ◽  
Local Dent

This paper investigates the collapse behaviour of stiffened panels with a local dent under axial compressive load. The damage on plates is simulated by quasi-static nonlinear FEM, which accounts for the residual stresses caused by a dent and the springback of the stiffened panels. The material properties used in the finite element analysis have been evaluated by tensile tests. To prescribe appropriate boundary conditions, extended stiffened panels with three bays models are adopted in FE analyses. The resistance of the stiffened panels to denting is analyzed first. The effects of residual stress, geometry model and dent depth of stiffened panels on the ultimate strength and the springback of the stiffened panels are analyzed.

Ultimate Strength of Stiffened Plates Subjected to Longitudinal Compression and Lateral Pressure

2014 ◽  
Author(s):  
Karan Doshi ◽  
Suhas Vhanmane
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Lateral Pressure ◽  
Stiffened Plates ◽  
Stiffened Panel ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Linear Finite Element ◽  
Non Linear ◽  
Compressive Loads

This paper presents a non-linear finite element analysis (FEA) and subsequent formula development for ultimate strength of stiffened panels of ship structures. A review of studies on ultimate strength of ship plating subjected to lateral pressure was carried out. The present work takes into account, the influence due to the lateral pressure on the ultimate strength of stiffened plates with initial imperfections subject to longitudinal compressive loads. ANSYS non-linear FE software was used for non linear finite element analyses of stiffened panels (864 cases) considering VLCC hull. Based on regression analysis, a set of semi-analytical formulae were proposed and described. It is observed that depending upon the failure mode, scantlings of the stiffened panel and magnitude of lateral pressure, ultimate strength of the stiffened panels in compression is affected.

Experimental and numerical investigation on ultimate strength of four-legged latticed columns

2021 ◽  
pp. 136943322110015
Author(s):  
Yinqi Li ◽  
Feng Liu ◽  
Wenming Cheng ◽  
Huasen Liu
Keyword(s):  
Ultimate Strength ◽  
Structural Engineering ◽  
Analytical Techniques ◽  
Experimental Tests ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Compressive Loads ◽  
Initial Geometric Imperfections ◽  
Combined Data ◽  
Loading Eccentricity

Latticed built-up columns are applied more extensively than solid columns in structural engineering because of their excellent load-carrying capacity and light weight. Studies on the bearing capacity of latticed columns, particularly multiple-legged latticed columns, need to be conducted in detail. In this investigation, seven four-legged latticed column specimens of different bar sections, bar distributions and loading eccentricities under compressive loads were subjected to experimental tests. The initial geometric imperfections of the legs and bars were measured and introduced into the FE numerical method. The experimental results were then compared with those of Geometrical and Material Non-Linear Analysis with Imperfection in ABAQUS software. The combined data indicate that the bar section, bar distribution and loading eccentricity significantly influenced the ultimate strength of four-legged latticed columns, producing maximum variations of 105.67%, 65.7% and 48.48%, respectively. This investigation demonstrates the influence of lacing bars and improves the results obtained from FE numerical analytical techniques.

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.

A Study on the Simplified Calculation Method for the Residual Ultimate Strength of Damaged Hull Structures

2016 ◽  
Author(s):  
Kimihiro Toh ◽  
Shunsuke Maeda ◽  
Takao Yoshikawa
Keyword(s):  
Ultimate Strength ◽  
Calculation Method ◽  
Fe Analysis ◽  
Structural Members ◽  
Average Strain ◽  
Non Linear ◽  
Compressive Loads ◽  
Calculation Results ◽  
Simplified Calculation ◽  
Simplified Calculation Method

In order to obtain the non-linear average stress-average strain relationships (σ-ε curves) of damaged structural members under both tensile and compressive loads, the systematical calculations are performed using the non-linear FE analysis (FEA) code, LS-DYNA, and the idealized σ-ε curves of damaged structural members are estimated from FEA results. In addition, by introducing the idealized σ-ε curves of damaged structural members to the simplified calculation program, which is developed by authors and based on the Smith’s method, the residual ultimate strength of damaged hull structures is calculated. The residual ultimate strength of damaged hull structures is also calculated utilizing FEA, the calculation results by the simplified calculation program are compared with the results obtained from FE analyses so as to examine the accuracy of simplified calculation method.

Advanced Closed-Form Ultimate Strength Formulation for Ships

2001 ◽  
Vol 45 (02) ◽  
pp. 111-132 ◽  
Author(s):  
Jeom Kee Paik ◽  
Owen F. Hughes ◽  
Alaa E. Mansour
Keyword(s):  
Ultimate Strength ◽  
Structural Damage ◽  
Lateral Pressure ◽  
Local Buckling ◽  
Bending Moment ◽  
Stiffened Panels ◽  
Initial Imperfections ◽  
Ship Hulls ◽  
Collapse Column ◽  
Side Shell

The aim of this paper is to develop an advanced ultimate strength formulation for ship hulls under vertical bending moment. Since the overall failure of a ship hull is normally governed by buckling and plastic collapse of the deck, bottom, and sometimes the side shell stiffened panels, it is of crucial importance to accurately calculate the ultimate strength of stiffened panels in deck, bottom and side shell for more advanced ultimate strength analyses. In this regard, the developed formulation is designed to be more sophisticated than previous simplified theoretical methods for calculating the ultimate strength of stiffened panels under combined axial load, in-plane bending and lateral pressure. Fabrication-related initial imperfections (initial deflections and residual stresses) and potential structural damage related to corrosion, collision, or grounding are included in the panel ultimate strength calculations as parameters of influence. All possible collapse modes involved in collapse of stiffened panels, including overall buckling collapse, column or beam-column type collapse (plate or stiffener induced collapse), tripping of stiffeners and local buckling of stiffener web, are considered. As illustrative examples, the paper investigates and discusses the sensitivity of parameters such as lateral pressure, fabrication-related initial imperfections, corrosion, collision and grounding damage on the ultimate strength of a typical Cape size bulk carrier hull under vertical bending.

An Analysis of the Ultimate Strength of Deck Structures Under In-Plane Loads

1983 ◽  
Vol 20 (03) ◽  
pp. 230-251
Author(s):  
Ygal Shapir ◽  
Gregory J. White
Keyword(s):  
Residual Stresses ◽  
Ultimate Strength ◽  
Experimental Results ◽  
Correction Factors ◽  
Buckling Strength ◽  
Step Procedure ◽  
Simple Program ◽  
Mode Of Failure ◽  
Compressive Loads ◽  
Simple Flow

A step-by-step procedure for determining the mode of failure and the ultimate strength of ship deck structures under in-plane compressive loads is developed. A comparison of several analytical theories for the buckling strength of deck structures in the elastic and inelastic zones is presented and the reason for the approach taken at each step is explained. The final result is a simple flow chart for this procedure and an algorithm which is easily adapted to most computer systems. The procedure is compared with experimental results and a method for determining reasonable size factors of safety (or correction factors) to account for initial deflections, residual stresses, etc., is presented. An example coding in FORTRAN IV for use as a subroutine in larger programs, or as a simple program itself, is given. An example structure is solved to explain each of the steps of the procedure.

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