Numerical Investigation of Ultimate Strength of Stiffened Plates With Various Cross-Section Forms

2018 ◽  
Author(s):  
Huilong Ren ◽  
Yifu Liu ◽  
Chenfeng Li ◽  
Xin Zhang ◽  
Zhaonian Wu
Keyword(s):  
Aluminum Alloy ◽  
Ultimate Strength ◽  
Cross Section ◽  
High Performance ◽  
Lightweight Design ◽  
Offshore Structures ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Element Analysis ◽  
Hull Structure

There is an increasing interest in the lightweight design of ship and offshore structures, more specifically, choosing aluminum alloys or other lightweight high-performance materials to build structure components and ship equipments. Due to its better mechanical properties and easy assembly nature, extruded aluminum alloy stiffened plates are widely used in hull structures. When the load on the hull reaches a certain level during sailing, partial or overall instability of stiffened plate makes significant contribution in an event of collapse of the hull structure. It is very necessary to investigate the ultimate strength of aluminum alloy stiffened plate to ensure the ultimate bearing capacity of large aluminum alloy hull structure. Most of studies of the ultimate strength of stiffened plates deal with stiffened plates with T–shaped stiffeners. Stiffeners of other shapes have seldom been explored. In this research, the ultimate strength of six different cross–section aluminum alloy stiffened plates and one steel stiffened plate was studied based on the non–linear finite element analysis (FEA). Taking into account stiffness, weight and other issues, the new cross–section aluminum stiffener has finally been concluded for replacing the original steel stiffener in upper deck of a warship.

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.

VIBRATION AND DYNAMIC INSTABILITY OF STIFFENED PLATES SUBJECTED TO IN-PLANE HARMONIC EDGE LOADING

2002 ◽  
Vol 02 (02) ◽  
pp. 185-206 ◽  
Author(s):  
A. K. L. SRIVASTAVA ◽  
P. K. DATTA ◽  
A. H. SHEIKH
Keyword(s):  
Dynamic Instability ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Element Analysis ◽  
Aspect Ratios ◽  
Stiffness Properties ◽  
Edge Loading ◽  
Instability Regions ◽  
Varying Mass ◽  
Good Agreement

The vibration and dynamic instability behavior of a stiffened plate subjected to uniform in-plane edge loading is studied using finite element analysis. The method of Hill's infinite determinants is applied to analyze the dynamic instability regions. Rectangular stiffened plates possessing different boundary conditions, aspect ratios, varying mass and stiffness properties and varying number of stiffeners have been analyzed for dynamic instability. The results are obtained considering the bending displacements of the plate and the stiffener. Eccentricity of the stiffeners give rise to axial and bending displacement in the middle plane of the plate. The results show that the principal instability regions have a significant effect considering and neglecting in-plane displacements. Comparison with published results indicates good agreement.

Ultimate strength of steel beam-columns under axial compression

2017 ◽  
Vol 231 (4) ◽  
pp. 828-843
Author(s):  
Zhongwei Li ◽  
Mayuresh Patil ◽  
Xiaochuan Yu
Keyword(s):  
Ultimate Strength ◽  
Axial Compression ◽  
Beam Theory ◽  
Computer Code ◽  
Offshore Structures ◽  
Element Analysis ◽  
Beam Columns ◽  
Geometrically Exact Beam ◽  
Steel Panels ◽  
Geometrically Exact Beam Theory

This article presents a semi-analytical method to calculate the ultimate strength of inelastic beam-columns with I-shaped cross section using geometrically exact beam theory. A computer code based on this method has been applied to beam-columns under axial compression. The results agree with nonlinear finite element analysis. Compared with previous step-by-step integration approach, this new method is more efficient and can be extended to multi-span beam-columns and other load combinations including lateral pressure. The presented beam-column model is ideally suited for ultimate strength prediction of stiffened steel panels of ships and offshore structures.

scholarly journals A Comparative Study of Piers with DSCT and Steel Piles

2021 ◽  
Vol 21 (6) ◽  
pp. 377-383
Author(s):  
Hyemin Hong ◽  
Sungwon Kim ◽  
Taek Hee Han
Keyword(s):  
Cross Section ◽  
High Performance ◽  
Climate Changes ◽  
Structural Safety ◽  
Element Analysis ◽  
Design Wave Height ◽  
Steel Piles ◽  
New Type ◽  
Buckling Failure ◽  
Height Increase

Because of climate changes, the demand for securing marine space is increasing owing to problems such as sea level rise, design wave height increase, and lack of land and space, and research on the development of a new high-performance pier has been conducted. In the existing pier supported by steel piles, buckling failure and corrosion problems may lead to a risk of structural safety, and maintenance is difficult owing to a narrow span. The new type of double-skinned composite tubular (DSCT) structure, which has been extensively studied recently, is filled with concrete between the inner and outer tubes, increasing the strength of concrete because of the three-axis confined effect. In addition, it is advantageous in terms of ductility. Furthermore, owing to the hollow cross-section, it is economical because it weighs less than the concrete-filled steel tubular (CFT) structure, effectively saving materials. In this study, the performance of a pier with 30 steel piles and that of a pier supported with 20 DSCT piles was compared under the same external force through finite element analysis. Consequently, it was confirmed that the pier with DSCT piles showed higher performance in displacement and stress than the existing pier with steel piles.

Finite Element Analysis of the Ultimate Strength of Aluminum-Stiffened Panels With Fixed and Floating Transverse Frames

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Chenfeng Li ◽  
Zhiyao Zhu ◽  
Huilong Ren ◽  
C. Guedes Soares
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Ultimate Strength ◽  
Simulation Method ◽  
Tensile Tests ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Aluminum Panels

The aim of this study was to analyze the ultimate strength of stiffened aluminum panels by the nonlinear finite element method. A new type of stiffened aluminum alloy panel has been designed, which has fixed longitudinal and alternating floating transverse frames. Based on material tensile tests, the material properties of the aluminum alloy were obtained. Then, the simulation method of welding residual stresses and the effect of heat-affected zone (HAZ) are investigated. The finite element analysis (FEA) software abaqus V6.11 is used to estimate the ultimate strength of these stiffened panels under axial compression. The results show that: (1) the mechanical imperfections have significant effect on the ultimate strength of stiffened panels; (2) residual stresses may have positive effect on the ultimate strength; and (3) the new stiffened panels also have good performance on ultimate bearing capacities.

Comparison Study of Various Buckling and Ultimate Strength Assessment Methodologies for Stiffened Panels in Offshore Structures

2010 ◽  
Author(s):  
Xiaozhi Wang ◽  
Haihong Sun ◽  
Xiaohong Wang ◽  
Zhinong Wang ◽  
Anil Thayamballi
Keyword(s):  
Ultimate Strength ◽  
Offshore Structures ◽  
Design Analysis ◽  
Plastic Behavior ◽  
Comparison Study ◽  
Element Analysis ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Linear Elastic ◽  
Local Strength

Strength of offshore structures including FPSOs consists broadly of three aspects which are global intact and damaged strength, and local strength. Any of these strength aspects can be assessed by either prescriptive rule or finite element analysis (FEA). While many considerations relate to behavior in the linear elastic regime, the buckling and ultimate strength of both structural components (plate and stiffened panels) and structural systems can involve material and geometric nonlinearity behavior beyond the elastic region. With the development of computers and robust methods for nonlinear FEA, there has been a tremendous increase in the number of studies of structures under plastic or elasto-plastic behavior. However, even with today’s computers and software, nonlinear FEA of offshore structures remains complex and is not routinely applied in design analysis. Considerable effort therefore continues to be devoted to the development of simplified methods for rapid structural assessment and design analysis, instead of lengthy and complex nonlinear FEA. In this paper, various bucking and ultimate strength methodologies for plate and stiffener panels are first introduced. Each method is then compared with collected test data for buckling and ultimate strength of plate panels and stiffeners. Finally, conclusions are summarized based on the comparison study.

scholarly journals Deformation of designed steel plates: An optimisation of the side hull structure using the finite element approach

2021 ◽  
Vol 11 (1) ◽  
pp. 1034-1047
Author(s):  
Aditya Rio Prabowo ◽  
Tuswan Tuswan ◽  
Dandun Mahesa Prabowoputra ◽  
Ridwan Ridwan
Keyword(s):  
Finite Element ◽  
Structural Parameters ◽  
Carbon Steels ◽  
Steel Plates ◽  
Stiffened Plates ◽  
Structural Behaviour ◽  
Element Analysis ◽  
Thin Walled Structures ◽  
Hull Structure ◽  
Thin Walled

Abstract Thin-walled structures, which generally consist of unstiffened and stiffened plates, are widely used in engineering as one of the core features of any product or construction. Due to environmental conditions and working operation, the components of the structure unavoidably become subject to various types of loading. Deformation patterns and overall behaviour are expected to be varied, as different materials are considered in the structures. In this situation, assessments are required to quantify the responses and determine the relationships between the structural behaviour and structural parameters. In this work, we attempt to obtain the behaviour data of unstiffened and stiffened plates as components of thin-walled structures. The material class – i.e. low- and medium-carbon steels – and loading parameters (i.e. type and angle) are taken as the main inputs in the finite element analysis. A geometrical design is adopted based on the side hull structure of a medium-sized tanker, for which two plate types, unstiffened and stiffened, are used. The results indicate that increasing the loading angle reduces the force experienced by the plate, while the greater the loading direction angle is, the greater the total displacement value will be. In terms of the plate design, the stiffener is observed to reduce the force expansion during the loading of the stiffened plate.

Cross-section optimization of thin-walled open-section composite column for maximizing its ultimate strength

2021 ◽  
pp. 146442072110462
Author(s):  
Prashant K Choudhary ◽  
Prashanta K Mahato ◽  
Prasun Jana
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Cross Section ◽  
Cross Sections ◽  
Ultimate Load ◽  
Material Failure ◽  
Element Analysis ◽  
Composite Column ◽  
Thin Walled ◽  
The Cross

This paper focuses on the optimization of thin-walled open cross-section laminated composite column subjected to uniaxial compressive load. The cross-section of the column is parameterized in such a way that it can represent a variety of shapes including most of the regular cross-sections such as H, C, T, and I sections. The objective is to obtain the best possible shape of the cross-section, by keeping a constant total material volume, which can maximize the ultimate load carrying capacity of the column. The ultimate strength of the column is determined by considering both buckling instability and material failure. For material failure, Tsai-Wu composite failure criterion is considered. As analytical solutions for these parameterized column models are not tractable, the ultimate loads of the composite columns are computed through finite-element analysis in ANSYS. And, the optimization is carried out by coupling these finite-element results with a genetic algorithm based optimization scheme developed in MATLAB. The optimal result obtained through this study is compared with an equivalent base model of cruciform cross-section. Results are reported for various lengths and boundary conditions of the columns. The comparison shows that a substantial increase of the ultimate load, as high as 610%, can be achieved through this optimization study. Thus, the present paper highlights some important characteristics of open cross-sections that can be useful in the design of thin-walled laminated column structures.

Research on Approaches to Aluminum Alloy Automotive Wheels' Lightweight Design

2013 ◽  
Vol 774-776 ◽  
pp. 465-468 ◽  
Author(s):  
Baoan Yang ◽  
Ya Ping Ye
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Aluminum Alloy ◽  
3D Modeling ◽  
Theoretical Basis ◽  
Lightweight Design ◽  
Element Analysis ◽  
Structure Characteristics ◽  
Modeling Technology ◽  
Analysis Theory

Wheels should meet strength requirements and achieve lightweight design. The analysis of structure characteristics of the aluminum alloy automotive wheels that are widely used was done. Based on the wheel radial fatigue test, the wheel's load was determined. The analysis of the wheel was done applying 3D modeling technology and FEA (finite element analysis) theory, and the results can be used as the theoretical basis of aluminum alloy automotive wheels' lightweight design.

Ultimate Strength Characteristics of a Ship's Deck Stiffened Plate Structure in the Presence of Camber Parabolic Curvature

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Mohammad Reza Khedmati ◽  
Pedram Edalat
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Parametric Model ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
Finite Element Program ◽  
Main Target ◽  
Element Program ◽  
Plane Compression ◽  
And Behavior

The main target of this research is to identify the effects of camber parabolic curvature on the ultimate strength and behavior of stiffened plates under in-plane compression. A parametric model for the study of the problem is created. The model includes different parameters related to plate, stiffeners, and also parabolic camber curvature. Three distinct sensitivity cases are assumed. In each sensitivity case, many different models are analyzed and their ultimate strengths are obtained using an in-house finite element program. Ultimate strength and behavior of the models with different ratios of parabolic curvature are compared to each other and interpreted.

Sign in / Sign up

Export Citation Format

Share Document