scholarly journals Mechanical Collapse Testing on Aluminum Stiffened Plate Structures for Marine Applications

2008 ◽  
Vol 45 (04) ◽  
pp. 228-240
Author(s):  
Jeom Kee Paik ◽  
Celine Andrieu ◽  
H. Paul Cojeen
Keyword(s):  
High Speed ◽  
Design Method ◽  
Limit State ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Design Standards ◽  
Element Analysis ◽  
Plate Structures ◽  
Initial Imperfections ◽  
Marine Applications

The present paper is a summary of the R&D results obtained through SSC SR-1446 project sponsored by Ship Structure Committee together with Alcan Marine, France, and Lloyd's Register Educational Trust, UK. It is recognized that the use of ultimate limit state (ULS) design method in addition to more conventional structural design standards will help make possible to move high-speed vessels to open-ocean transiting of large high-speed vessels, which is what the US Navy is certainly trying to do. The aim of the project is to investigate the collapse characteristics of aluminum stiffened plate structures used for marine applications by mechanical testing, together with nonlinear finite element analysis (FEA). Fabrication-related initial imperfections significantly affect the ULS behavior, and thus it is of vital importance to identify the features of initial imperfections prior to ULS computations. In the present study, a statistical database of fabrication-related initial imperfections on welded aluminum stiffened plate structures is also developed. The database and insights developed will be useful for design and building of welded aluminum high-speed oceangoing vessel structures.

Evaluation of IACS Common Structural Rules in Terms of Ultimate Limit State Design and Assessment of Ship Structures

2007 ◽  
Author(s):  
Jeom Kee Paik ◽  
Bong Ju Kim ◽  
Jung Kwan Seo
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Hull Girder ◽  
Structural Rules ◽  
Out Of Plane ◽  
Common Structural Rules ◽  
Ultimate Limit

The aim of the present paper is to evaluate the ultimate limit state performance of an AFRAMAX-class hypothetical double hull oil tanker structure designed by IACS CSR (Common Structural Rules) method, compared with the same-class/type tanker structure designed by IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck and bottom parts under combined in-plane and out-of-plane actions, and hull girder against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, while ALPS/HULL program is employed for the progressive hull collapse analysis. ANSYS nonlinear FEA method, which uses more refined technology, is also used for the same purpose. The insights and developments obtained from the present study are addressed.

Considering Catenary Action in Designing End-Restrained Steel Beams in Fire

2005 ◽  
Vol 8 (3) ◽  
pp. 309-324 ◽  
Author(s):  
H. X. Yu ◽  
J. Y. Richard Liew
Keyword(s):  
Design Method ◽  
Load Capacity ◽  
Limit State ◽  
Beam Deflection ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Catenary Action ◽  
In Fire

When a building compartment is subjected to fire attack, there are complex interactions between the fire affected members with the surrounding members. The behaviour of the steel frame members in fire can be drastically different from that of its member in isolation. This paper studies the behaviour of steel beams with the increase of temperature from beam action phase to catenary action phase and until failure. The load bearing mechanism in the catenary action phase is discussed and the failure criterion is defined. A new ultimate limit state based on 15% maximum strain of steel material at elevated temperature is proposed to determine the ultimate load capacity of beams failed in the catenary action phase. Wide ranges of beam parameters including various beam sizes and span lengths with different degrees of end restraints are studied. Comparison of results with those obtained from nonlinear finite element analysis shows that the proposed design method could enhance the critical temperature of steel beams by over 200 °C if proper attention is given to the integrity of connections to resist the catenary force. In this respect, methods to estimate the catenary force and beam deflection are provided.

Ultimate Limit State Performance of 170k Bulk Carrier Structures: Pre-CSR versus CSR Designs

2009 ◽  
Vol 46 (03) ◽  
pp. 174-182
Author(s):  
Jeom kee Paik ◽  
Jin Young Kim ◽  
Min Soo Kim
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Bulk Carrier ◽  
Plate Structures ◽  
Structural Rules ◽  
Similar Class ◽  
Common Structural Rules ◽  
Ultimate Limit

The objective of the present paper is to evaluate the ultimate limit state (ULS) performance of 170k bulk carrier structures designed by the IACS common structural rules (CSR) method, compared with the similar-class/type bulk carrier structure designed by the IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck, side, and bottom parts, and hull girders against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, and ALPS/HULL program is employed for the progressive hull collapse analysis. The insights and developments obtained from the present study are documented.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

RELIABILITY OF CORRODED STIFFENED PLATE SUBJECTED TO UNIAXIAL COMPRESSIVE LOADING

2021 ◽  
Vol 162 (A4) ◽  
Author(s):  
K Woloszyk ◽  
Y Garbatov
Keyword(s):  
Mechanical Properties ◽  
Reliability Index ◽  
Structural Reliability ◽  
Limit State ◽  
Plate Thickness ◽  
Thickness Reduction ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Initial Imperfections ◽  
Subsequent Decrease

The work is focused on the reliability of corroded stiffened plates subjected to compressive uniaxial load based on the progressive collapse approach as stipulated by the Common Structural Rules for Bulk Carriers and Oil Tankers, employing the limit state design. Two different cases have been investigated. In the first model, the corrosion degradation led to uniform thickness loss, whereas the mechanical properties were unchanged, as given in the Rules. In the second model, the plate thickness degradation was followed by mechanical properties reduction. The uncertainties related to the mechanical properties, thicknesses, and initial imperfections of the corroded stiffened plate were taken into account. Several initial design solutions of stiffened plates, as well as different severity levels of corrosion degradation were investigated. The results show that structural reliability significantly decreases with corrosion development, especially when in addition to the initial imperfections and corrosion plate thickness reduction, corroded plate surface roughness and the changes in the mechanical properties were considered. The uncertainties, their origins and confidence levels are discussed. It was found that non-linear time-dependent corrosion degradation accounting not only for the thickness reduction due to corrosion wastage but also the subsequent decrease of mechanical properties lead to a significant reduction in the reliability index. Additionally, it was defined that the reliability estimate is very sensitive to the uncertainties related to the initial thickness and the spread of corrosion degradation as a function of the time. Incorporating the probability of corrosion detection into the original reliability model introduces additional information about the validity of structural degradation that may lead to a higher beta reliability index estimate compared to the original model.

Full-Scale Measurements of Welding-Induced Initial Deflections and Residual Stresses in Steel-Stiffened Plate Structures

2018 ◽  
Vol Vol 160 (A4) ◽  
Author(s):  
M S Yi ◽  
C M Hyun ◽  
J K Paik
Keyword(s):  
Residual Stresses ◽  
Ultimate Strength ◽  
Computational Models ◽  
Plate Thickness ◽  
Offshore Structures ◽  
Full Scale ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Initial Imperfections ◽  
Numerical Predictions

Plated structures such as ships and offshore structures are constructed using welding techniques that attach support members (or stiffeners) to the plating. During this process, initial imperfections develop in the form of initial deformations (deflections or distortions) and residual stresses. These initial imperfections significantly affect the buckling and ultimate strength of these structures. Therefore, to assess the strength of welded plate structures, it is very important to predict the magnitude and pattern of welding-induced initial imperfections and their effects on buckling and ultimate strength. To determine the reliability of the prediction methods, it is desirable to validate the theoretical or numerical predictions of welding-induced initial imperfections through comparison with full-scale actual measurements. However, full-scale measurement databases are lacking, as they are costly to obtain. This study contributes to the development of a full-scale measurement database of welding-induced initial imperfections in steel-stiffened plate structures. The target structures are parts of real (full-scale) deckhouses in very large crude oil carrier class floating, production, storage and offloading unit structures. For parametric study purposes, four test structures by varying plate thickness are measured while the stiffener types and weld bead length are fixed. Modern technologies for measuring initial deformations and residual stresses are applied. The details of the measurement methods are documented for the use of other researchers and practicing engineers who want to validate their computational models for predicting welding-induced initial imperfections.

Risk Analysis for the Construction Phases of Long-Span CFST Arch Bridge Based on Finite Element Analysis

2011 ◽  
Vol 225-226 ◽  
pp. 823-826
Author(s):  
Yu Feng Zhang ◽  
Guo Fu Sun
Keyword(s):  
Finite Element ◽  
Risk Analysis ◽  
Limit State ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Nonlinear Buckling ◽  
Finite Element Program ◽  
Arch Bridge ◽  
Cfst Arch Bridge ◽  
Element Program

As a part of virtual simulation of construction processes, this paper deals with the quantitative risk analysis for the construction phases of the CFST arch bridge. The main objectives of the study are to evaluate the risks by considering an ultimate limit state for the fracture of cable wires and to evaluate the risks for a limit state for the erection control during construction stages. Many researches have been evaluated the safety of constructed bridges, the uncertainties of construction phases have been ignored. This paper adopts the 3D finite element program ANSYS to establish the space model of CFST Arch Bridge, and to calculate the linear, the geometrical nonlinear and the double nonlinear buckling safety factors under the six different lode cases. Then the bridge’s risks are evaluated according to the results calculated which provide a reference for design of similar project.

scholarly journals Structural analisys of concrete pre-stressed reservoirs for sludge fermentation – water waste treatment plant bucharest – glina. numerical fem assessment of the structural response for static in-duty loads

2013 ◽  
Vol 9 (1) ◽  
pp. 42-58
Author(s):  
Tudor Bugnariu
Keyword(s):  
Waste Treatment ◽  
Numerical Models ◽  
Limit State ◽  
Treatment Plant ◽  
Structural Response ◽  
Soil Mass ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Waste Treatment Plant ◽  
Water Waste

Abstract The paper refers to a structural finite element analysis on the reservoirs for sludge fermentation subjected to static in-duty loads, at Glina Water Waste Treatment Plant. The purpose was to assess the stress and deformation states in subsequent erection and service conditions, to verify the design provisions and to emphasize the sensitivities, for a structure which was designed in the ‘80s based on analytical procedures. The results obtained on the numerical models highlight the importance of the soil-structure interaction, in peculiar the one influenced by the soil mass deformability, on the overall structural response. Based on the calculated stresses, all structural components were verified according to the actual design codes at the ultimate limit state and the service limit state (water tightness/crack emergence).

scholarly journals A RATIONALIZED SEISMIC DESIGN METHOD FOR BUILDINGS IN EARTHQUAKE-PRONE DEVELOPING COUNTRIES

2021 ◽  
Vol 11 (4) ◽  
pp. 266-279
Author(s):  
Tint Lwin ◽  
Takeshi Koike ◽  
Ji Dang
Keyword(s):  
Developing Countries ◽  
Seismic Design ◽  
Design Method ◽  
Limit State ◽  
Design Procedure ◽  
Ultimate Limit State ◽  
Design Guideline ◽  
Seismic Safety ◽  
Seismic Design Method ◽  
Ultimate Limit

In general, the US codes such as the UBC-97 and ASCE-7 are widely used in developing countries including Myanmar, Syria, Philippines and so on. When the current seismic design guideline based on the UBC-97 and ACI 318-99 in Myanmar is assessed, several problems can be found in the following items: firstly, the fundamental period is not checked in modeling; secondly, reduction factor R is introduced a priori for the base shear estimation. And finally, a limit state assessment is done only for Design Basic Earthquake (DBE) but not for other design earthquakes. As a result, adequate yield strength is not checked for Maximum Operational Earthquake (MOE). Then there is no way to assess the seismic safety of the ultimate limit state for Maximum Considered Earthquake (MCE). In order to solve these problems, a rationalized seismic design method for earthquake prone developing countries is proposed. A new seismic design method is developed for MOE and MCE with adequate yield acceleration and typical period of the building estimated by using pushover analysis. A simplified procedure to estimate the inelastic response for a given design spectrum is also proposed. Finally, this design procedure can provide a rational method to assess the seismic safety for the ultimate limit of the building.

scholarly journals Numerical Modelling of Glass Fiber Reinforced Polymer (GFRP) Cross Arm

2019 ◽  
Vol 8 (4) ◽  
pp. 6484-6489
Keyword(s):  
Failure Modes ◽  
Limit State ◽  
Geometrical Model ◽  
Fiber Direction ◽  
Ultimate Limit State ◽  
Element Analysis ◽  
Plane Shear ◽  
Glass Fiber Reinforced ◽  
Out Of Plane ◽  
The Matrix

Composites are not isotropic like their metal counterparts, e.g. steel and aluminum, as they are made of two distinctive phases known as the matrix and the reinforcing phases. In addition, weight, fiber direction, fiber composition and even the manufacturing process are all critical factors in determining the strength, stiffness and the behaviour of a composite member. All of that create more challenging designing and manufacturing approaches. This paper shows how to model a GFRP cross arm using SOLIDWORKS to create the 3D geometrical model because it has an intuitive and easy to use user interface, and ANSYS to create the numerical model and the analysis for its great and comprehensive capabilities in the finite element analysis. The cross arm was found to be safe against the failure modes of fiber, matrix, in-plane shear, out-of-plane shear and delamination under all load cases which satisfies the ultimate limit state requirements but the concern was on the serviceability limit state which had a deflection of 34 mm.

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