Sensitivity Study About Ultimate Strength and Postbuckling Behavior of Stiffened Box Deck Girder Under Compression

2020 ◽  
Author(s):  
Chunqi Zhou ◽  
Dan Song
Keyword(s):  
Ultimate Strength ◽  
Structural Strength ◽  
Local Buckling ◽  
Initial Imperfection ◽  
Sensitivity Study ◽  
Structure Design ◽  
Variable Load ◽  
Offshore Platforms ◽  
Postbuckling Behavior ◽  
Engineering Project

Abstract The proper determination of this paper is to study the ultimate strength and postbuckling behavior for complicated stiffened deck girders of offshore platforms. Normally, offshore platforms are designed with reinforcing stiffeners on box deck girder. The box deck of column stabilized platform will be simulated with FEM software ABAQUS. Linear eigenvalue analysis is firstly applied to introduce the initial imperfection into the structure. Then the non-linear postbuckling analysis for the box deck girder will illustrate ultimate strength and the failure mode under axial load after collapse. The ways how the stiffeners, eigenmode and imperfections influence the ultimate capacity will also be analyzed. Comparing variable elements affecting the structural strength, the work shows the offshore box deck girder section from the engineering project in this paper is quite robust to the axial compression. For this kind of robust design, such as the box deck girder, the eigenmode selection and amplitude of imperfection will exert slight effects on the ultimate strength, but the severe imperfections will accelerate the local buckling. Stiffeners design will exert dramatic influence on the ultimate strength and postbuckling behaviors. And the work to find the optimum balance among structural strength variable load and allowable imperfections seems to be very promising in engineering. The conclusions provide a more clear insight into the further optimization of the offshore square structure design.

scholarly journals Experimental and Numerical Investigations of Ultimate Strength of Imperfect Stiffened Plates of Different Slenderness

2020 ◽  
Vol 27 (4) ◽  
pp. 120-129
Author(s):  
Krzysztof Woloszyk ◽  
Yordan Garbatov ◽  
Jakub Kowalski ◽  
Leszek Samson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Compressive Force ◽  
Initial Imperfection ◽  
Element Model ◽  
Stiffened Plates ◽  
Structural Behaviour ◽  
Middle Cross Section ◽  
Geometrical Imperfections

AbstractThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive force, and the most important quantities related to the structural behaviour were captured and analysed. A finite element model, accounting for material and geometrical nonlinearities and initial geometrical imperfections, was developed using the commercial software ANSYS. The residual welding-induced stresses were measured in the middle cross-section for two specimens. The initial imperfection was identified by employing a close-range photogrammetry approach. It was concluded that the numerical analyses, based on the finite element model, predict the ultimate strength of stiffened plates accurately, although some deviations were also observed. The detailed analysis with the indication of possible uncertainty is presented, and several conclusions are derived.

Structure design for variable load

Networks ◽  
2009 ◽  
pp. 126-134
Author(s):  
Peter Whittle
Keyword(s):  
Structure Design ◽  
Variable Load

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

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.

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.

Buckling and Postbuckling of Sandwich Beams With Delaminated Faces Based on Higher Order Core Theory

1999 ◽  
Author(s):  
R. F. Li ◽  
Y. Frostig ◽  
G. A. Kardomateas
Keyword(s):  
Nonlinear Distortion ◽  
Variational Principles ◽  
Vertical Direction ◽  
Initial Imperfection ◽  
Order Theory ◽  
Sandwich Beams ◽  
Postbuckling Behavior ◽  
The Core ◽  
Core Theory ◽  
The Face

Abstract Delaminations within the face sheets are often observed when a sandwich structure is exposed to impact loads. The buckling and postbuckling behavior of sandwich beams with delaminated faces is investigated in this work. The governing nonlinear equations, boundary conditions, and continuity conditions are formulated through variational principles. The beam construction consists of upper and lower, metallic or composite laminated symmetric skins, and a soft core of a foam or low strength honeycomb type. A high order theory is used for the core that accounts for the nonlinear distortion of the plane of section of the core and the compressibility in the vertical direction. The delamination considered is an interface crack, in which the substrate includes the transversely flexible core. The case of a debond at one of the skin-core interfaces is also included. The effects of the delamination length and location on the overall and local behavior are examined with an arbitrary initial imperfection.

The Consideration of Welding Profiles in Fatigue Evaluation of Structure Design

2006 ◽  
Author(s):  
D. Zhang
Keyword(s):  
Fatigue Life ◽  
Engineering Design ◽  
Structural Design ◽  
Structure Design ◽  
Offshore Platforms ◽  
Efficient Design ◽  
Structural Fatigue ◽  
Different Shapes ◽  
Fatigue Evaluation ◽  
The Impact

Structural fatigue plays a very important role in plating structural design. There are a lot of efforts in finding effective ways to improve the fatigue life of the plating structure. One of the means is to use welding profile. Welding profile is widely used in fatigue sensitive areas to improve the fatigue life of offshore platforms. How to evaluate the impact of welding profile to fatigue life calculation has always been the topic of engineering design. This paper will study the impact of different shapes of welding profiles to the fatigue life of structure through a real project example, and discuss its application in platform design. Different welding profiles have large impact on fatigue life; and an achievable good welding profile can improve the fatigue life dramatically. With the help of welding profiles, offshore engineers can achieve a more efficient design of the structure.

EVALUATIONS OF REMAINING STRENGTH ESTIMATION METHOD BY USING PLATE GIRDER MODELS WITH CORROSION UNDER SLEEPERS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Naoyuki Asao ◽  
Katashi Fujii
Keyword(s):  
Ultimate Strength ◽  
Estimation Method ◽  
Local Buckling ◽  
Past Research ◽  
Local Corrosion ◽  
Substantial Impact ◽  
Local Loads ◽  
Plate Girders ◽  
The Relationship ◽  
Plate Girder

In steel railway bridges with open deck system, the local buckling of compressive flanges under sleepers on plate girders caused by the local corrosion of flanges leads to the collapse of bridges. The local corrosion is thought to have a substantial impact on the ultimate strength of main girders. However, past research on ultimate strength contains few inquiries into the relationship between the local corrosion of compressive flanges and the ultimate strength of main girders, and a method of evaluating the relationship has not yet been established. In this study, parameter analyses that focus on plate girders with local corrosion under sleepers have been conducted by using full-scale plate girder models subjected to bending and local loads simultaneously. Then based on these analytical values and other existing experimental values, the study verified the applicability of the separate evaluation equations that we previously proposed for remaining load bearing capacity under bending and local loads respectively, as well as the remaining strength calculation method based on the strength interaction curve of plate girders subjected to bending and local loads simultaneously to clarify that ultimate strength can be evaluated with a high degree of accuracy.

scholarly journals Cellular buckling from mode interaction in I-beams under uniform bending

2011 ◽  
Vol 468 (2137) ◽  
pp. 245-268 ◽  
Author(s):  
M. Ahmer Wadee ◽  
Leroy Gardner
Keyword(s):  
Variational Principles ◽  
Structural Strength ◽  
Local Buckling ◽  
Numerical Continuation ◽  
Mode Interaction ◽  
Lateral Torsional Buckling ◽  
Post Buckling ◽  
Strength And Stiffness ◽  
First Time ◽  
Differential And Integral Equations

Beams made from thin-walled elements, while very efficient in terms of the structural strength and stiffness to weight ratios, can be susceptible to highly complex instability phenomena. A nonlinear analytical formulation based on variational principles for the ubiquitous I-beam with thin flanges under uniform bending is presented. The resulting system of differential and integral equations are solved using numerical continuation techniques such that the response far into the post-buckling range can be portrayed. The interaction between global lateral-torsional buckling of the beam and local buckling of the flange plate is found to oblige the buckling deformation to localize initially at the beam midspan with subsequent cellular buckling (snaking) being predicted theoretically for the first time. Solutions from the model compare very favourably with a series of classic experiments and some newly conducted tests which also exhibit the predicted sequence of localized followed by cellular buckling.

Ultimate Strength Analysis of Ship Hull Girder Under Random Material and Geometric Properties

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Suhas Vhanmane ◽  
Baidurya Bhattacharya
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Initial Imperfection ◽  
Statistical Dependence ◽  
Strength Analysis ◽  
Bulk Carrier ◽  
Geometric Properties ◽  
Hull Girder ◽  
Initial Imperfections ◽  
Different Levels

The ultimate strength of a ship’s hull depends on its material and geometric properties, some or all of which may be random in nature. In addition, initial imperfections in the form of initial deflection and residual welding stresses in plating between stiffeners can significantly affect the hull ultimate strength. In this paper, the effect of randomness in yield strength and in the initial imperfections on ultimate hull girder strength is determined. Different levels of statistical dependence between yield strength and initial imperfection of stiffeners and plating between stiffeners have been considered. The methodology is applied on a bulk carrier and a VLCC tanker.

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