Estimation of Ultimate Limit Statefor Stiffened-Plates Structures: Applying for a Very Large Ore Carrier Structures Designed by IACS Common Structural Rules

2012 ◽  
Vol 249-250 ◽  
pp. 1012-1018
Author(s):  
Hung Chien Do ◽  
Wei Jiang ◽  
Jian Xin Jin
Keyword(s):  
International Association ◽  
Limit State ◽  
Offshore Structures ◽  
Biaxial Compression ◽  
Stiffened Plates ◽  
Ultimate Limit State ◽  
Ship Structures ◽  
Structural Rules ◽  
Common Structural Rules ◽  
Ultimate Limit

In advanced marine industry, the reduction in weight of hull structures for a very large object ship plays an important role as the economic efficiency is the most significant aspect. In this paper, we investigate the ultimate strength of structural ship stiffened-plates designed by International Association of Classification Societies (IACS) Common Structural Rules (CSR) methods of collapse state, by applying for ANSYS nonlinear finite element analysis (FEA). Specifically, the ultimate limit assessment methods for the outer bottom of ship structures, which have drawn a significant attention from industrial marine and offshore structures, are proposed to reduce the weight of ship structures. To solve this, we study the structures of a hypothetical Very Large Ore Carrier (VLOC) designed by pre-CSR and CSR methods. In particular, the stiffened-plates under the biaxial compression and lateral pressure loads with simply supported or/and clamped boundary condition(s), the results ultimate limit state assessment performance of Nonlinear FEA methods are shown and compared to various states.

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.

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.

Evaluation of Uncertainties in Loadings on Offshore Structures due to Extreme Environmental Conditions

1993 ◽  
Vol 115 (4) ◽  
pp. 237-245 ◽  
Author(s):  
R. G. Bea
Keyword(s):  
Environmental Conditions ◽  
Epistemic Uncertainty ◽  
Limit State ◽  
Offshore Structures ◽  
Ultimate Limit State ◽  
Mackenzie Delta ◽  
Loading Effects ◽  
Load Effects ◽  
Available Information ◽  
Ultimate Limit

This paper summarizes results from a Canadian Standards Association (CSA) sponsored study of the uncertainties associated with extreme (1000 to 10,000-yr return periods) environmental loadings acting on offshore structures (Bea, 1991). The evaluations of the loadings addressed loading effects that resulted from dynamic and nonlinear interactions of the structures. Loading uncertainties were organized and characterized in two categories: 1) inherent randomness (aleatory uncertainty), and 2) analytical variability (epistemic uncertainty). The study addressed the global ultimate limit state performance of three structures designed according to the provisions of the draft CSA guidelines (1989a, 1989b) for offshore structures: 1) a concrete Gravity Base Structure (GBS) located off the East coast of Canada (Hibernia), 2) a steel pile template located on the Scotian Shelf off Sable Island, and 3) a caisson retained island located in the Mackenzie Delta area of the Beaufort Sea (Amuligak). The results of this study indicate that, based on presently available information and data, it is often not possible to develop unambiguous characterizations of uncertainties. The different technical communities that background environmental conditions and forces (storms, earthquakes, ice) recognize and integrate these uncertainties into loading characterizations in different ways. In many cases, major sources of uncertainty are not included in probabilistic characterizations. Because of the needs for design code information sensitivity and consistency in demonstrating compliance with target reliability goals, there is a need for well-organized and definitive evaluations of uncertainties in extreme environmental loadings and load effects (Bitner-Gregersen et al., 1993).

scholarly journals Ultimate Limit State Analysis of Ship Structures

2019 ◽  
Author(s):  
S Sathish Kumar
Keyword(s):  
Ultimate Load ◽  
Progressive Collapse ◽  
Limit State ◽  
Structural Response ◽  
Load Factor ◽  
Ultimate Limit State ◽  
Ship Structures ◽  
Limit State Analysis ◽  
Ultimate Limit ◽  
State Analysis

Subjective and objective uncertainties are imposed on ship structures due to the random nature of the loading environment, inadequate knowledge of physical phenomena associated with loads or deviations in material properties which make reliable predictions of structural response a difficult task. Strength criteria for ships can be established by ultimate strength studies of progressive collapse analysis of finite element models under different boundary conditions with combined geometric and material nonlinearities. Load-Displacement and/or Moment-Curvature curves can be generated and the ultimate load causing failure identified as a multiple of the design load. Ultimate limit state analysis can be carried out for various combinations of parameters to identify the ultimate load factor in each case.

Advanced Ultimate Strength Formulations for Ship Plating Under Combined Biaxial Compression/Tension, Edge Shear, and Lateral Pressure Loads

2001 ◽  
Vol 38 (01) ◽  
pp. 9-25
Author(s):  
Jeom Kee Paik ◽  
Anil K. Thayamballi ◽  
Bong Ju Kim
Keyword(s):  
Ultimate Strength ◽  
Lateral Pressure ◽  
Limit State ◽  
Biaxial Compression ◽  
Ultimate Limit State ◽  
Initial Imperfections ◽  
Interaction Equation ◽  
Collapse Behavior ◽  
The Individual ◽  
Ultimate Limit

The aim of the present study is to develop more advanced design formulations for the ultimate strength of ship plating than available at present. Plate ultimate strength subject to any combination of the following four load components—longitudinal compression/tension, transverse compression/tension, edge shear, and lateral pressure loads—is addressed. The developed formulations are designed to be more sophisticated than existing theoretically based simplified methods. The influence of post-weld initial imperfections in the form of initial deflections and residual stresses is taken into account. It has been previously recognized that a single ultimate strength interaction equation cannot successfully represent the ultimate limit state of long and/or wide plating under all possible combinations of load components involved. This is due to the fact that the collapse behavior of the long and/or wide plating depends primarily on the predominant load components, implying that more than one strength interaction formulations may be needed to more properly predict the plate ultimate limit state. In this regard, the present study derives three sets of ultimate strength formulations for the long and/or wide plating under the corresponding primary load by treating lateral pressure as a secondary dead load. The ultimate strength interaction formula under all of the load components involved is then derived by a relevant combination of the individual strength formulas. The validity of the proposed ultimate strength equations is studied by comparison with nonlinear finite-element analyses and other numerically based solutions.

scholarly journals Ultimate Limit State Design Technology for Aluminum Multi-Hull Ship Structures

2005 ◽  
Author(s):  
Jeom Kee Paik ◽  
Owen F. Hughes ◽  
Paul E. Hess ◽  
Celine Renaud
Keyword(s):  
Ultimate Strength ◽  
Limit State ◽  
Extensive Study ◽  
Stiffened Panel ◽  
Ultimate Limit State ◽  
Ship Structures ◽  
Strength Assessment ◽  
Hull Girder ◽  
National University ◽  
Ultimate Limit

The present paper is a summary of recent research and developments related to some core ultimate limit state (ULS) technologies for design and strength assessment of aluminum multi-hull ship structures, jointly undertaken by Pusan National University, Virginia Tech, U.S. Naval Surface Warfare Center and Alcan Marine. An extensive study on the subject has been undertaken by the authors theoretically, numerically and experimentally. Methods to analyze hull girder loads / load effects, stiffened panel ultimate strength and hull girder ultimate strength of aluminum multi-hull ship structures are developed in the present study. Application examples of the methodologies for the ULS structural design and strength assessment of a hypothetical 120m long all aluminum catamaran fast ship structure are presented. Important insights and conclusions developed from the present study are summarized. Some of the comparisons have shown that 5383 called Sealium (a patented Alcan Marine alloy) is superior to the standard aluminum alloy 5083 in terms of material properties, ULS characteristics and welding performance. It is our hope that the methods developed from the present study will be useful for ULS design and strength assessment of aluminum multi-hull ship structures.

On the Behavior and Design of Stiffened Plates in Ultimate Limit State

1978 ◽  
Vol 22 (04) ◽  
pp. 238-244
Author(s):  
T. H. Soreide ◽  
T. Moan ◽  
N.T. Nordsve
Keyword(s):  
Finite Element ◽  
Limit State ◽  
Axial Loading ◽  
Stiffened Plates ◽  
Ultimate Limit State ◽  
Element Formulation ◽  
Finite Element Program ◽  
Global Buckling ◽  
Element Program ◽  
Ultimate Limit

The behavior and design of stiffened plates in the ultimate limit state are studied. A finite element formulation for panel behavior considering general loading conditions, material properties, geometry, boundary conditions, and initial deflections is presented. Some results obtained by a finite element program are displayed and discussed. The problems considered comprise perfect and initially deflected plate-strips subjected to lateral pressure, single-span and two-span beam-columns under axial loading, and failure of a stiffened plate designed for simultaneous local and global buckling. Finally, design criteria are briefly discussed and recommendations for future work are given.

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