scholarly journals Ultimate strength formulation of stiffened panels under in-plane compression or tension with cracking damage

2018 ◽  
Vol 15 (1) ◽  
pp. 1-16
Author(s):  
Mohammad Reza Zareei ◽  
Mehdi Iranmanesh
Keyword(s):  
Risk Assessment ◽  
Regression Analysis ◽  
Closed Form ◽  
Ultimate Strength ◽  
Nonlinear Fem ◽  
Stiffened Panels ◽  
Plane Compression ◽  
Steel Panels ◽  
Stiffened Steel

The aim of the present study is to develop closed-form formulations for predicting the ultimate compressive and tensional strength of stiffened steel panels with crack damages. First, a numerical database is generated. This database includes the ultimate strength levels of stiffened steel panels with cracks subjected to axial compressive or tensile loads. It was carried out with a series of nonlinear FEM analyses by varying the size of crack damage. In the following sections, regression analysis is used for deriving the empirical formulations. The results of the present paper can be used for the reliability and risk assessment of structures, including stiffened steel panels with cracks. 

Ultimate Strength of Dented Narrow Stiffened Panels Subjected to Compressive Loads

2012 ◽  
Author(s):  
Mingcai Xu ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Compressive Load ◽  
Tensile Tests ◽  
Nonlinear Fem ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Geometry Model ◽  
The Finite Element Analysis ◽  
Compressive Loads ◽  
Local Dent

This paper investigates the collapse behaviour of stiffened panels with a local dent under axial compressive load. The damage on plates is simulated by quasi-static nonlinear FEM, which accounts for the residual stresses caused by a dent and the springback of the stiffened panels. The material properties used in the finite element analysis have been evaluated by tensile tests. To prescribe appropriate boundary conditions, extended stiffened panels with three bays models are adopted in FE analyses. The resistance of the stiffened panels to denting is analyzed first. The effects of residual stress, geometry model and dent depth of stiffened panels on the ultimate strength and the springback of the stiffened panels are analyzed.

Ultimate Strength of Aluminum Plates and Stiffened Panels for Marine Applications

2004 ◽  
Vol 41 (03) ◽  
pp. 108-121
Author(s):  
Jeom Kee Paik ◽  
Alexandre Duran
Keyword(s):  
Aluminum Alloys ◽  
Ultimate Strength ◽  
Material Properties ◽  
Plastic Material ◽  
Steel Structures ◽  
Material Model ◽  
Stiffened Panels ◽  
Elastic Plastic ◽  
Steel Panels ◽  
Aluminum Plates

The use of high-strength aluminum alloys in marine construction has certainly obtained many benefits, particularly for building fast ferries and also for military purposes. It is commonly accepted that the collapse characteristics of aluminum structures are similar to those of steel structures until and after the ultimate strength is reached, regardless of the differences between them in terms of material properties. However, it is also recognized that the ultimate strength design formulas available for steel panels cannot be directly applied to aluminum panels even though the corresponding material properties are properly accounted for. This is partly due to the fact that the stress versus strain relationship of aluminum alloys is different from that of structural steel. That is, the elastic-plastic regime of material after the proportional limit and the strain hardening plays a significant role in the collapse behavior of aluminum structures, in contrast to steel structures where the elastic perfectly plastic material model is well adopted. Also, the softening in the heat-affected zone significantly affects the ultimate strength behavior of aluminum structures, whereas it can normally be neglected in steel structures. In this paper, the ultimate strength characteristics of aluminum plates and stiffened panels under axial compressive loads are investigated through ANSYS elastic-plastic large deflection finite element analyses with varying geometric panel properties. An "average" level of welding-induced softening and initial imperfections is assumed for the analyses. Closed-form ultimate compressive strength formulas for aluminum plates and stiffened panels are derived by regression analysis of the computed results.

scholarly journals An empirical study on open position risk assessment using VAR and regression analysis: A case study of Iranian banking industry

2012 ◽  
Vol 2 (6) ◽  
pp. 2135-2140 ◽  
Author(s):  
Mohammad Khodaei Valahzaghard ◽  
Mina Ghavidel ◽  
Mojtaba Heidar ◽  
Elmira Mahmoudzadeh
Keyword(s):  
Risk Assessment ◽  
Regression Analysis ◽  
Empirical Study ◽  
Banking Industry ◽  
Open Position

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

Buckling and Ultimate Strength Assessment of FPSO Structures

2005 ◽  
Author(s):  
Haihong Sun ◽  
Xiaozhi Wang
Keyword(s):  
Ultimate Strength ◽  
Oil And Gas ◽  
Element Analysis ◽  
Strength Criteria ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Oil And Gas Fields ◽  
Extensive Test ◽  
Offshore Oil And Gas ◽  
Classification Society

Floating production, storage and offloading systems (FPSOs) have been widely used for the development of offshore oil and gas fields because of their attractive features. They are mostly ship- shaped, either converted from existing tankers or purposely built, and the hull structural scantling design for tankers may be applicable to FPSOs. However, FPSOs have their unique characteristics. FPSOs are sited at specific locations with a dynamic loading that is quite different from those arising from unrestricted service conditions. The structures are to be assessed to satisfy the requirements of all in-service and pre-service loading conditions. The fundamental aspects in the structural assessment of FPSOs are the buckling and ultimate strength behaviors of the plate panels, stiffened panels and hull girders. The focus of this paper is to address the buckling and ultimate strength criteria for FPSO structures. Various aspects of the criteria have been widely investigated, and the results of the design formulae proposed in this paper have been compared to a very extensive test database and numerical results from nonlinear finite element analysis and other available methods. The procedures presented in this paper are based on the outcomes of a series of classification society projects in the development of buckling and ultimate strength criteria and referred to the corresponding classification society publications.

The Effective Use of Experimental and Numerical Data for Validating Simplified Expressions of Stiffened Steel Panel Ultimate Compressive Strength

2007 ◽  
Vol 44 (02) ◽  
pp. 93-105
Author(s):  
Jeom Kee Paik
Keyword(s):  
Experimental Data ◽  
Compressive Strength ◽  
Numerical Data ◽  
Numerical Results ◽  
Design Code ◽  
Stiffened Panels ◽  
Collapse Mode ◽  
Effective Use ◽  
Stiffened Steel ◽  
Sophisticated Analysis

To study the accuracy of simplified formulations for prediction of the ultimate strength of longitudinally stiffened panels under uniaxial compression, the preferred approach is to compare them with available experimental data or numerical results from more sophisticated analysis procedures. Such studies are necessary in the development of both design code calibrations and reliability analysis procedures. Existing experimental data and numerical results useful for this purpose are first collected. Salient features of existing design formulations for compressive strength are then reviewed. Selected formulations are compared with the experimental data/numerical results. It is illustrated that there can be a significant amount of scatter in strength estimates by any one formulation and among formulations. The reasons for such scatter are discussed, with the emphasis on the collapse mode(s) involved, the effective width of plating, initial imperfections, and rotational restraints due to stiffening. The experimental and numerical strength data collected are documented for convenience of future use by other investigators.

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.

Sign in / Sign up

Export Citation Format

Share Document