Ultimate Strength Of Steel Plates Research Articles

Compression capacity of corroded plates with three sides simply supported and one side free

Steel plates have been widely used in various structures, including building structures, bridges, ocean platforms, and industrial equipment. The ultimate strength of steel plates can be substantially affected by corrosion. The influence of corrosion on ultimate strength of steel plates with three sides simply supported and one side free is quantified. The stochastic numerical analysis is adopted and the reliability of established stochastic FE model is firstly verified by comparing with analytical results. The feasibility of derived results for steel plates with different width- thickness ratios (b/t) ratios is investigated. The analytical formulas for predicting the reduction factor Θ are proposed. The influence of aspect ratio, geometrical imperfection and corroded thickness on the changing rule of reduction factor along with mass loss ratio are systematically investigated. The conclusion can establish a foundation for the buckling behavior of corroded steel plates.

Artificial neural networks for predicting ultimate strength of steel plates with a single circular opening under axial compression

ABSTRACT In the current paper, using finite element models (FEM), an extensive numerical study is performed on the behaviour of the steel plates with a circular hole in their centre subjected to compressive axial loading. For this purpose, 270 perforated steel plates were modelled and analysed using ABAQUS software. The effects of four main variables including plate length, hole diameter, plate thickness, and yield stress were discussed. Then, using the database provided by FEM, the artificial neural network (ANN) method was used to develop a predictive model to estimate the ultimate strength of steel plates with a circular hole in the centre. Finally, an ANN-based formula was proposed to predict the ultimate strength of perforated steel plates and its accuracy was compared with the formulations presented in previous studies. Based on the results, the proposed formula provided high accuracy and can be used as a reliable formula in practice.

Residual Ultimate Strength of Steel Plates with Longitudinal Crack and Pitting Corrosion under Axial compression: Nonlinear Finite Element Method Investigations

The main aim of present study was to determine the ultimate strength of cracked and corroded plates under uniform in-plane compression. Corrosion is considered as pitting-type corrosion at one side of the plate with a central longitudinal crack. Nonlinear finite element analysis using commercial computer code, ANSYS, is used to determine the ultimate strength of deteriorated plates. Different geometrical parameters, including the aspect ratio (AR) and thickness of the plate, number of pits, pit depth-to-thickness ratio, and crack length, are considered. It is found that the AR of plates have great influence on the ultimate strength of cracked-pitted plates. Because of the position and orientation of the crack, the length of central longitudinal crack has no influence on ultimate strength reduction of cracked and cracked-pitted plates. The results show that regardless of the number of pits and crack length, in thin plates where buckling controls failure modes at ultimate strength, the number of pits has less influence on reduction of the ultimate strength than thick plates where yielding controls failure mode. Also it is concluded that in rectangular plates, arrangements of pits has more effect on reduction of the ultimate strength of cracked-pitted plates than the number of pits.

A Computational Investigation of the Group Effect of Pits on the Ultimate Strength of Steel Plates

In this work, we focus on assessing the group effect of localized corrosion on the ultimate strength of the marine structural plates and study the load-deformation behaviors of plates of various slenderness and uniaxial compression. Meanwhile, we investigate different corroded patterns from a single circular pit to 25 circular pits distributed over the plate and carry out hundreds of nonlinear finite element simulations by combining the number, depth, distribution of pits with imperfections and slenderness of plate. The distribution of multiple pits causes scattering of stress concentration on the plate, then the plastic section of plate changes with wider distribution of damage simultaneously. The ultimate strength arises when un-loading zone comprised of the yielding strips and holes extends across the plate. It can be concluded that the corroded condition defined as group effect of pits manipulates the deformation state and the loading capacity of plate at the ultimate strength mode that coincides with the proportion of effective loading area and section in the process of post-buckling. To validate the effect of pits group, we perform the numerical experiments of the post-buckling of steel plates containing pits in a row with different orientation.

Structural capacity of plates and stiffened panels of different materials with opening

This work experimentally investigates the influence of different opening sizes and shapes, different steel materials and structural configurations on the ultimate strength of steel plates. A series of experiments have been carried out for unstiffened plates and stiffened panels having an opening of different shape and size in addition to different constructional steels; high tensile and mild steel. The effect on the ultimate load carrying capacity of the opening sizes and shapes, different steels and structural configurations, post-collapse deformations and strain energy density are investigated and analysed. Several relationships of the ultimate stress ratio, ultimate load carrying capacity ratio for different steels as a function of the residual breadth ratio are presented and discussed. A relationship showing the effect of different structural configurations on the ultimate load carrying capacity ratio is presented. Several observations and concluding remarks are derived from the experimental results.

A review and study on ultimate strength of steel plates and stiffened panels in axial compression

This paper presents a review and study on ultimate strength analysis methods for steel plates and stiffened panels in axial compression. Buckling and collapsing mechanisms of steel plates and stiffened panels are described. Analysis approaches for ultimate strength and their employments in ship designs are reviewed and discussed. A study and further validation on the authors developed formula for ultimate strength of stiffened panels using a comprehensive non-linear finite element analysis, 110 models in total, and a wide range of model test results, 70 models in total, are carried out. Finally, applications of the developed formula to existing oil tankers and bulk carriers are presented.

Residual ultimate strength of steel plates with longitudinal cracks under axial compression—Nonlinear finite element method investigations

The main objective of the present paper is to numerically examine the residual ultimate strength characteristics of steel plates with longitudinal cracks under axial compressive actions. The present paper is a sequel to the author's previous paper [Paik, J.K., 2008. Residual ultimate strength of steel plates with longitudinal cracks under axial compression—Experiments. Ocean Engineering 35, 1775–1783]. In contrast to the previous paper, the present paper deals with nonlinear finite element method investigations. Because the test programme is usually limited to a few test models in number for many reasons, the application of nonlinear finite element methods is often more beneficial to handle a more variety of parameters of influence. In the present paper, the insights developed from a series of ANSYS nonlinear finite element method computations are documented, where the effects of the crack orientation, the crack location, the crack size, the plate thickness, and the plate aspect ratio on the residual ultimate strength of steel plates with longitudinal cracks under axial compression are discussed. The insights developed from the present work will be useful for cracking damage-tolerant design of steel-plated structures and also for health monitoring or condition assessment of aging steel-plated structures with cracking damages.

Residual ultimate strength of steel plates with longitudinal cracks under axial compression–experiments

The main objective of the present study is to examine the residual ultimate strength characteristics of steel plates with cracking damages under axial compressive actions through experimental investigations. The present study is a sequel of the author's previous paper (Paik, J.K., Satish Kumar, Y.V., Lee, J.M., 2005. Ultimate strength of cracked plate elements under axial compression or tension. Thin-Walled Structures, 43, 237–272). In contrast to the previous paper which dealt with transverse cracks located in the direction normal to the axial loading direction, the present paper is concerned with longitudinal cracks which are located in parallel to the axial loading direction. Similar to the previous paper, the orientation/location and size of cracks inside the plates are varied for the present experimental investigations. The details of experimental results are documented. The database and insights developed from the present work will be useful for cracking damage-tolerant design of steel-plated structures and also for condition assessment or health monitoring of aging steel-plated structures.

Ultimate strength of steel plates with a single circular hole under axial compressive loading along short edges

The aim of the present study is to investigate the ultimate strength characteristics of steel plates with a single circular hole under axial compressive loading along short edges, which is a primary action type arising from vertical or horizontal hull girder bending moments of ships and ship-shaped offshore structures. The plates are considered to be simply supported along all (four) edges and kept straight. The circular hole is located at the center of the plate. A series of ANSYS nonlinear finite element analyses (FEA) are undertaken with varying the hole size (diameter) as well as plate dimensions (plate aspect ratio and thickness). By regression analysis of the FEA results obtained, a closed-form empirical formula for the ultimate longitudinal compressive strength of perforated plates, which can be useful for first-cut strength estimations and reliability analyses, is derived. The accuracy of the ultimate strength formula developed is verified by a comparison with more refined nonlinear FEA results.

Effect of pitting corrosion on the ultimate strength of steel plates subjected to in-plane compression and bending

Corrosion pits with a circular cone shape are typically observed on coated hold frames of aged bulk carriers which carry exclusively coal and iron ore. In order to ensure the safety of these types of bulk carrier, it is necessary to understand the effect of pitting corrosion on the local strength of hold frames. In order to investigate this effect, a series of nonlinear finite-element (FE) analyses has been performed with pitted plates subjected to in-plane compressive loads and bending moments. It has been shown that the ultimate compression load or bending moment of pitted plates is smaller than that of uniformly corroded plates in terms of average thickness loss, and that predictions of the ultimate strength using the average thickness loss at the minimum cross section would be conservative. In order to establish a method of evaluating strength reduction due to pitting corrosion, it is important to identify the failure mode that would be most detrimentally affected by pitting corrosion. It was found that the reduction of the ultimate compressive load or bending moment due to pitting corrosion is smaller than that of the tensile strength in terms of equivalent thickness.

301 一軸圧縮を受ける鋼板の最終強度に及ぼす腐食ピットの影響(GS1(1) 変形,破壊挙動,疲労,クリープ,衝撃)

301 一軸圧縮を受ける鋼板の最終強度に及ぼす腐食ピットの影響(GS1(1) 変形,破壊挙動,疲労,クリープ,衝撃)

腐食ピットが発生している構造部材の等価板厚評価に関する研究

Pitting corrosion is a great concern when the integrity of ship's hull structures is considered. Corrosion pits with a conical shape are typically observed on coated hold frames in way of cargo holds of bulk carriers which exclusively carry coal and iron ore. In the present study, a series of non-linear FE-analyses has been conducted to investigate the effect of such pitting corrosion on local strength of hold frames using various structural models, that is, collapse models accompanying no buckling, lateral-torsional buckling models, local buckling models, shear buckling models and web crippling models. It has been revealed that the ultimate strength obtained in the present analyses for all the structural models except shear buckling models could be well predicted by the empirical formula, which was developed in the previous study to estimate the ultimate strength of steel plates under compression and shear. In the case of shear buckling models, it depends on the web thickness whether the empirical formula could be applied or not.

Local Buckling of Steel Plates in Double Skin Composite Panels under Biaxial Compression and Shear

[Abstract]: Steel plates in double skin composite (DSC) panels are restrained by a concrete core and welded stud shear connectors at discrete positions. Local buckling of steel plates in DSC panels may occur in a unilateral mode between stud shear connectors when subjected to combined states of stresses. This paper studies the local and postlocal buckling strength of steel plates in DSC panels under biaxial compression and in-plane shear by using the finite element method. Critical local buckling interaction relationships are presented for steel plates with various boundary conditions that include the shear stiffness effects of stud shear connectors. A geometric and material nonlinear analysis is employed to investigate the postlocal buckling interaction strength of steel plates in biaxial compression and shear. The initial imperfections of steel plates, material yielding, and the nonlinear shear–slip behavior of stud shear connectors are considered in the nonlinear analysis. Design models for critical buckling and ultimate strength interactions are proposed for determining the maximum stud spacing and ultimate strength of steel plates in DSC panels.

An experimental investigation on the dynamic ultimate compressive strength of ship plating

The aim of the present study is to obtain experimental data on the ultimate strength of steel plates under dynamically applied axial compressive loads. A series of dynamic collapse tests were carried out on steel plate models under axial compressive loads, varying the loading speed. Based on the test results, the effect of loading speed (or strain rate) on the ultimate strength of steel plates is investigated. Relevant useful formulations for assessing the dynamic ultimate compressive strength of steel plates are also derived as a function of the strain rate by curve fitting. The test data developed are documented.

Parametric Study on the Structural Behaviour of Steel Plates in Concrete-Filled Fabricated Thin-Walled Box Columns

A theoretical investigation of the post-local buckling behaviour and ultimate strength of steel plates in concrete-filled fabricated box columns is presented. The finite element method is used to predict the post-local buckling response of plates restrained by concrete. Geometric imperfections and residual stresses are considered in the analysis. The model developed is initially compared with a classical solution for clamped plates with initial imperfections. An extensive parametric study is then carried out to investigate the minimum local buckling coefficient and the effects of geometric imperfections and residual stresses on the post-local buckling strength of clamped steel plates. An effective width model is proposed for the design of clamped steel plates, and this can be used in the determination of the ultimate strength of short concrete-filled box columns. Independent test results of concrete-filled steel box columns are compared with the theoretical predictions by using the proposed design model. It is confirmed that the proposed design model predicts the behaviour of real concrete-filled steel box columns extremely well.

Experimental study on ultimate strength of stiffened plates subjected to longitudinal tension and transverse compression

The ultimate strength of steel plates with longitudinal stiffeners of open or closed cross-section subjected to both longitudinal tension and transverse compression is experimentally investigated in this study. Four stiffened plate specimens on the scale of one-third, corresponding to that of the steel deck plate in an actual Nielsen Lohse bridge, were tested by using an experimental apparatus newly developed for this study. The test results verify a practical design method, which the authors developed for predicting the ultimate strength of stiffened plates subjected to biaxial in-plane forces.

EVALUATION OF ULTIMATE STRENGTH OF STEEL PLATES WITH INITIAL IMPERFECTIONS UNDER IN-PLANE BENDING AND COMPRESSION

There are few studies on the ultimate strength of steel plates under in-plane combined loading, and their basic strength curves in the design specifications in many countries are still based on the elastic buckling theory using relevant safety factors. Evaluation in the ultimate strength is essential to promote the ultimate limit-state design method. This paper presents the ultimate strength of plate panel under in-plane stress gradient. Based on the analytical results, the ultimate strength formulas for uniform compress and pure bending are proposed, respectively and the interaction formula for the combined loading of compression and bending are then proposed.

A STUDY ON CHARACTERISTICS OF ULTIMATE STRENGTH OF STEEL PLATES WITH INITIAL IMPERFECTIONS UNDER IN-PLANE BENDING AND COMPRESSION

A STUDY ON CHARACTERISTICS OF ULTIMATE STRENGTH OF STEEL PLATES WITH INITIAL IMPERFECTIONS UNDER IN-PLANE BENDING AND COMPRESSION

Ultimate strength of eccentrically loaded steel plates and box sections

A finite element method is applied to compute the elastic-plastic post-buckling behavior of initially deflected and eccentrically loaded steel plates and box sections. Comparisons with available theoretical and experimental results reveal that the present finite element analysis gives extremely accurate results even with small numbers of elements. Based on an extensive numerical study, an empirical formula is proposed to predict the ultimate strength of steel plates as well as steel box sections with various supporting conditions.