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.

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

2020 ◽  
Author(s):  
Do Kyun Kim ◽  
Su Young Yu ◽  
Hui Ling Lim ◽  
Nak-Kyun Cho
Keyword(s):  
Compressive Strength ◽  
Ultimate Strength ◽  
Limit State ◽  
Ultimate Compressive Strength ◽  
Stiffened Panel ◽  
Ultimate Limit State ◽  
Longitudinal Compression ◽  
Strength Performance ◽  
Different Types ◽  
Ultimate Limit

This research aims to study the ultimate limit state (ULS) behaviour of stiffened panel under longitudinal compression by non-linear finite element method (NLFEM). There are different types of stiffeners 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 of reliable scenarios of flat-bar stiffened panel are selected for numerical simulation by ANSYS NLFEM. The ultimate strength behaviours obtained were used as data for the development of closed form shape empirical formulation. Recently, Kim et al. [1] proposed for advanced empirical formulation for T-bar stiffened panel and the applicability of the proposed formulation to flat-bar stiffened panel will be confirmed by this study. The accuracy of the empirical formulation obtained for flat-bar stiffened panel has been validated by 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.

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 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.

scholarly journals EXAMPLE OF GRAGUAL TRANSFORMATION OF STIFFNESS MATRIX AND MAIN SET OF EQUATIONS AT ADDITIONAL FINITE ELEMENT METHOD

2020 ◽  
Vol 16 (2) ◽  
pp. 14-25
Author(s):  
Anna Ermakova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stiffness Matrix ◽  
Limit State ◽  
Ultimate Limit State ◽  
Nonlinear Properties ◽  
Design Diagram ◽  
Ultimate Limit ◽  
Gradual Transformation ◽  
Element Method

The paper considers the example of gradual transformation of the stiffness matrix and the main set of equations at Additional Finite Element Method (AFEM). It is corresponded to the increase of load and the ideal failure model of structure. AFEM uses the additional design diagrams and additional finite elements (AFE) for this operation. This process is illustrated by the transformation of design diagram of bended concrete console from the beginning of its loading to the collapse. The structure reveals four physical nonlinear properties before the ultimate limit state. Every nonlinear property appears under the action of corresponded load. The stiffness matrix and the set of equations are changed under influence of the value of load and the presence of observed nonlinear properties at this moment.

scholarly journals Assessment of Buckling Behaviour on an FPSO Deck Panel

2020 ◽  
Vol 27 (3) ◽  
pp. 50-58 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Finite Element ◽  
Limit State ◽  
Practical Interest ◽  
Structural Response ◽  
Ultimate Limit State ◽  
Imperfection Sensitivity ◽  
Stiffened Panels ◽  
Structural Capacity ◽  
Response Subject ◽  
Ultimate Limit

AbstractStiffened plates are the main structural building block in ship and offshore hulls and their structural response subject to loads is a topic of significant practical interest in ship and offshore structural design. To investigate the structural capacity for design and evaluation purposes, it is becoming an efficient and reliable practice to carry out non-linear finite element (FE) analysis. The present study is to assess the buckling strength of a stiffened deck panel on an FPSO vessel using the nonlinear finite element code ADVANCE ABAQUS, where imperfection sensitivity work is also accounted for. The cases studied correspond to in-plane bi-axial compression in the two orthogonal directions. The findings are compared with the DNVGL PULS (Panel Ultimate Limit State) buckling code for the stiffened panels. It is found that the strength values from the ADVANCE ABAQUS and DNVGL PULS code are very close. The results and insights developed from the present work are discussed in detail.

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.

Compressive Strength of Stiffened Plates With Imperfections: Simple Design Equations

2008 ◽  
Vol 52 (03) ◽  
pp. 227-237
Author(s):  
Koji Masaoka ◽  
Alaa Mansour
Keyword(s):  
Finite Element ◽  
Compressive Strength ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Ultimate Compressive Strength ◽  
Initial Deflection ◽  
Stiffened Plates ◽  
Simple Design ◽  
Column Buckling ◽  
The Impact

The behavior and ultimate compressive strength of stiffened plates with imperfections have been investigated in this paper using a nonlinear finite element method. The imperfections considered consisted of initial deflection and residual stresses. Several types of initial deflections were investigated, including those that may initiate stiffener column buckling and stiffener tripping. Extensive parametric study was conducted in order to systematically determine the impact of these initial imperfections on the ultimate compressive strength of stiffened plates of various geometric properties and stiffener shapes. The objective of the study was to develop simple design equations for determining ultimate strength based on finite element parametric study. The developed algebraic equations reflect the impact of imperfections on ultimate strength. A Perry-Robertson type equation was developed to incorporate the influence of the imperfections. It was found that under certain conditions a hybrid type mode of failure was necessary to accurately represent the behavior of stiffened plates with imperfections, in addition to the usual plate and stiffener failure modes. It was also found that column buckling type initial deflection is the most important form of imperfection.

Effect of the Installation Process on the Pullout Capacity of Helical Anchors

2021 ◽  
Author(s):  
Abdul Kader El Haj ◽  
Abdul-Hamid Soubra
Keyword(s):  
Finite Element ◽  
Sandy Soil ◽  
Limit State ◽  
Soil Disturbance ◽  
Ultimate Limit State ◽  
Ultimate Capacity ◽  
Pullout Capacity ◽  
Fe Method ◽  
Ultimate Limit ◽  
Large Deformation Problems

Abstract In this paper, an advanced numerical method called Coupled Eulerian-Lagrangian (CEL) method is used for the prediction of the behavior of helical anchors in sandy soil under ultimate limit state ULS including the effect of anchor installation process. The CEL analysis allows one to overcome the drawback of the classical finite element FE method in the case of large deformation problems as it takes the advantages of both Lagrangian and Eulerian methodologies. Results have shown that the CEL analysis is relevant for the computation of the helical anchor pullout capacity. Indeed, the CEL analysis was able to rigorously determine the ultimate capacity of the anchor contrary to the classical FE method; the calculation via the CEL approach has been carried out for relatively large displacement values without encountering any problem of convergence. Furthermore, CEL analysis was able to simulate the installation process of the anchor and thus enables one to consider the effect of the soil disturbance induced by the installation process on the computed pullout capacity. The numerical simulations have shown that the pullout capacity of the helical anchor may be significantly decreased when considering the anchor installation effect.

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