Theoretical and Experimental Study on the Ultimate Strength of Corrugated Bulkheads

1997 ◽  
Vol 41 (04) ◽  
pp. 301-317
Author(s):  
Jeom K. Paik ◽  
Anil K. Thayamballi ◽  
Min S. Chun
Keyword(s):  
Ultimate Strength ◽  
Lateral Pressure ◽  
Limit State ◽  
Plate Thickness ◽  
Experimental Information ◽  
Design Guidelines ◽  
Design Parameters ◽  
Collapse Mechanism ◽  
Ultimate Limit State ◽  
Analytical Formulation

The objectives of the present study are to obtain experimental data on collapse strength of steel corrugated bulkhead models and also to develop a simple analytical formulation for ultimate strength useful in the design of corrugated bulkheads under static lateral pressure. Collapse tests on nine mild steel corrugated bulkhead models having five bays of corrugations are carried out, varying the corrugation angle, the plate thickness and the type of loading (axial compression and/or lateral pressure). Using the test data, the characteristics of the collapse mechanism for corrugated bulkheads are investigated. For purposes of rapid first cut estimates of strength, a new and simple analytical formulation for predicting the ultimate strength of corrugated bulkheads under hydrostatic pressure is derived based on an assumed stress distribution over the corrugation cross section at the ultimate limit state. The modeling error associated with the new formulation is established by comparing its predictions with the experimental results. The development of ultimate strength based design guidelines and the effect of design parameters such as the corrugation angle on ultimate strength of a corrugated bulkhead are then discussed. All experimental information and strength data are tabulated, which is a benefit in itself.

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.

Ultimate Strength and Effective Width Formulations for Ship Plating Subject to Combined Axial Load, Edge Shear, and Lateral Pressure

2000 ◽  
Vol 44 (04) ◽  
pp. 247-258 ◽  
Author(s):  
Jeom Kee Paik ◽  
Anil K. Thayamballi ◽  
Bong Ju Kim
Keyword(s):  
Closed Form ◽  
Ultimate Strength ◽  
Axial Load ◽  
Lateral Pressure ◽  
Plate Theory ◽  
Limit State ◽  
Ultimate Limit State ◽  
Effective Width ◽  
Ultimate Shear Strength ◽  
Initial Imperfections

The aim of the present study is to develop closed-form formulations for the ultimate strength of simply supported steel plating subject to a combination of longitudinal axial load, edge shear, and lateral pressure. The post-weld initial imperfections (initial deflections and residual stresses) are included in the strength formulations as parameters of influence. By solving the equilibrium and compatibility governing differential equations of large-deflection plate theory, the membrane stress distribution inside the plating under axial and lateral pressure loads is formulated in closed form. The ultimate strength formulation for plating under axial load and lateral pressure is then derived under the assumption that the ultimate limit state is reached if the plate edges yield. An empirical formula for the plate ultimate shear strength is suggested based on numerical FE solutions. A relevant ultimate strength relationship between axial load and edge shear is then proposed by combining the two sets of the ultimate strength formulations. As another contribution, the effective width formulation for plating under combined axial compression and edge shear which allows for the shear lag effect caused by lateral pressure as well as the influence of post-weld initial imperfections is developed. The validity of the proposed ultimate strength formulations is shown by comparing with experimental results and nonlinear finite-element analyses. Modeling uncertainty of the developed plate ultimate strength formula against the experimental and numerical results is studied in terms of bias and coefficients of variation.

A Method for Structural Design of Pontoon Type VLFS Based on Collapse Behavior and Reliability Analysis

2004 ◽  
Author(s):  
Hiroo Okada ◽  
Koji Masaoka ◽  
Takashi Tsubogo ◽  
Shinji Katsura ◽  
Shin-Ichi Kawamata
Keyword(s):  
Reliability Analysis ◽  
Lateral Pressure ◽  
Limit State ◽  
Plate Thickness ◽  
Estimation Method ◽  
Bending Moment ◽  
Irregular Waves ◽  
Design Parameters ◽  
Load Effect ◽  
Collapse Behavior

This paper deals with a simplified method for the preliminary design of pontoon-type very large floating structures (VLFS), which are supposed floating airport, based on collapse behavior and reliability analysis in irregular waves. Firstly, a simplified estimation method is presented for the probabilistic load effect model of VLFS under irregular sea-state conditions. Next, limit state conditions are shortly presented for the buckling and ultimate collapse strength of stiffened plates under combined compression, shear and lateral pressure in the deck, bulkhead and bottom parts of VLFS, especially, by using a simplified estimation formula. Then, the validity is shown by non-linear finite element method. Finally, dominant limit state modes of 5,000m-class VLFS under combined loads with bending moment, shear force and lateral pressure are obtained by applying the above methods. Then, the features of the collapse behavior and reliability level are investigated by using above calculation results. Effects of design parameters such as yield stress, plate thickness, stiffener and bulkhead space are also investigated using sensitivity analysis.

Statistical evaluation of model factors in reliability calibration of high-displacement helical piles under axial loading

2020 ◽  
Vol 57 (2) ◽  
pp. 246-262 ◽  
Author(s):  
Chong Tang ◽  
Kok-Kwang Phoon
Keyword(s):  
Limit State ◽  
Axial Loading ◽  
Design Guidelines ◽  
Resistance Factor ◽  
Hyperbolic Model ◽  
Ultimate Limit State ◽  
Dense Sand ◽  
Capacity Model ◽  
Helical Piles ◽  
Two Parameters

An industry survey suggests an increasing application of high-displacement helical piles with greater shaft and helix diameters to support various structures. In this paper, a database of 84 static load tests is compiled and analyzed to evaluate the disturbance effect and characterize the model factors that can be used for reliability-based limit state design. The measured capacity is defined as the load at a pile head settlement equal to 5% of helix diameter. For similar helix configurations tested at the same site, the ratio of uplift to compression capacity indicates a low degree of disturbance for very stiff clay (0.8–1) and a medium degree of disturbance for dense sand (0.6–0.8). At the ultimate limit state, the model factor is defined as the ratio between measured and calculated capacity, where three design guidelines are considered. A hyperbolic model with two parameters is used to fit the load–displacement curves. At the serviceability limit state, the model factor can be defined with the hyperbolic parameters. Based on the database, probabilistic distributions of the capacity model factor and hyperbolic parameters are established. Finally, the capacity model statistics are applied to calculate the resistance factor in the load and resistance factor design.

Joint Description Methods of Wind and Waves for the Design of Offshore Wind Turbines

2009 ◽  
Vol 43 (3) ◽  
pp. 23-33 ◽  
Author(s):  
Kim E. Mittendorf
Keyword(s):  
Wind Energy ◽  
Wind Wave ◽  
Limit State ◽  
Wave Model ◽  
Design Guidelines ◽  
Offshore Wind ◽  
Ultimate Limit State ◽  
Wave Loads ◽  
Offshore Wind Energy ◽  
The North

AbstractWind and wave loads are equally important for the design of offshore wind energy structures. For the design against an ultimate limit state or fatigue, the engineer has to estimate the combination of loads that are likely to occur simultaneously during the design life of the wind turbine. This is quite a complex task, involving different wind/wave models, load-calculation methods and statistical analysis of simultaneous extreme wind and wave conditions. Moreover, reliable and realistic methods for the assessment of the service life of an offshore wind energy converter under combined wind and wave loads are necessary. However, the current design guidelines (Det Norske Veritas or German Lloyd) provide hardly any information on how to model the wind and wave correlation. In this article, several approaches for obtaining the required wind-wave correlation for the design have been investigated. Manual wave forecasting methods, spectral sea state descriptions and numerical wave model data have been compared to simultaneously measured wind and wave data from the FINO research platform in the German Bight of the North Sea. The used approaches are general and can be easily applied to different data sets from different regions.

scholarly journals On Characteristics of Ice Ridges and Icebergs for Design of Ship Hulls in Polar Regions Based on Environmental Design Contours

2021 ◽  
Vol 11 (12) ◽  
pp. 5749
Author(s):  
Bernt J. Leira ◽  
Wei Chai ◽  
Gowtham Radhakrishnan
Keyword(s):  
Probabilistic Models ◽  
Limit State ◽  
Relevant Information ◽  
Interaction Process ◽  
Contour Method ◽  
Design Parameters ◽  
Ultimate Limit State ◽  
Polar Regions ◽  
Ship Hulls ◽  
Structural Resistance

Ice ridges and icebergs generally pose a major threat to both ships and offshore facilities that operate in Polar regions. In many cases these features will govern the structural design loads associated with the Ultimate Limit State (ULS) and the Accidental Limit State (ALS). In general, a large number of load cases must be considered in order to ascertain an adequate structural resistance. Alternatively, conservatively high values of the relevant design parameters can be applied, which implies cost penalties. Accordingly, it is natural to consider methods that can serve to reduce the number of relevant load cases. Based on relevant information about the statistical properties of the parameters that characterize ice ridges and icebergs, the most likely combinations of these parameters for design purposes are highly relevant. On this background, the so-called environmental contour method is applied. Probabilistic models of the key parameters that govern the ship and ice interaction process are introduced. Subsequently, the procedure referred to as inverse reliability methods (IFORM) is applied for identification of the environmental contour. Different forms (i.e., dimensions) of environmental contours are generated to reflect the characteristics of the interaction process. Furthermore, the effect of an increasing correlation between the basic parameters is studied. In addition, the increase of the design parameter values for increasing encounter frequencies is illustrated.

Ultimate Strength of Stiffened Panels With Cracking Damage Under Axial Compression or Tension

2006 ◽  
Vol 50 (03) ◽  
pp. 231-238
Author(s):  
Jeom Kee Paik ◽  
Y. V. Satish Kumar
Keyword(s):  
Ultimate Strength ◽  
Limit State ◽  
Reliability Assessment ◽  
Nonlinear Finite Element ◽  
Stiffened Panel ◽  
Ultimate Limit State ◽  
Finite Element Analyses ◽  
Stiffened Panels ◽  
Aging Steel ◽  
Ultimate Limit

The aim of the present paper is to investigate the ultimate strength characteristics of a longitudinally stiffened panel with cracking damage and under axial compressive or tensile loads. A series of nonlinear finite element analyses are undertaken with varying the size and location of cracking damage. A relevant theoretical model for predicting the ultimate strength of the stiffened panel with cracking damage is studied. The insights and results developed from the present study will be very useful for the ultimate limit state-based risk or reliability assessment of aging steel plated structures with cracking damage.

scholarly journals Ultimate Compressive Strength of Stiffened Panel: An Empirical Formulation for Flat-Bar Type

2020 ◽  
Vol 8 (8) ◽  
pp. 605 ◽  
Author(s):  
Do Kyun Kim ◽  
Su Young Yu ◽  
Hui Ling Lim ◽  
Nak-Kyun Cho
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Ultimate Strength ◽  
Limit State ◽  
Ultimate Compressive Strength ◽  
Stiffened Panel ◽  
Ultimate Limit State ◽  
Longitudinal Compression ◽  
Strength Performance ◽  
Ultimate Limit

This research aims to study the ultimate limit state (ULS) behaviour of stiffened panel under longitudinal compression by a non-linear finite element method (NLFEM). There are different types of stiffeners mainly being used in shipbuilding, i.e., T-bar, flat-bar, and angle-bar. However, this research focuses on the ultimate compressive strength behaviour of flat-bar stiffened panel. A total of 420 reliable scenarios of flat-bar stiffened panel were selected for numerical simulation by the ANSYS NLFEM. The ultimate strength behaviours obtained were used as data for the development of closed form shape empirical formulation. Recently, our group proposed an advanced empirical formulation for T-bar stiffened panel, and the applicability of the proposed formulation to flat-bar stiffened panel is confirmed by this study. The accuracy of the empirical formulation obtained for flat-bar stiffened panel was validated by finite element (FE) simulation results of statistical analysis (R2 = 0.9435). The outcome obtained will be useful for ship structural designers in predicting the ultimate strength performance of flat-bar type stiffened panel under longitudinal compression.

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