The Experts below are selected from a list of 15975 Experts worldwide ranked by ideXlab platform
Chien Ming Wang - One of the best experts on this subject based on the ideXlab platform.
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Plastic-Buckling of Rectangular Plates under Combined Uniaxial and Shear Stresses
Journal of Engineering Mechanics, 2009Co-Authors: Chien Ming Wang, Tun Myint Aung, Sritawat Kitipornchai, Yang XiangAbstract:This paper is concerned with the plastic-Buckling of rectangular plates under uniaxial compressive and shear Stresses. In the prediction of the plastic-Buckling Stresses, we have adopted the incremental theory of plasticity for capturing the inelastic behavior, the Mindlin plate theory for the effect of transverse shear deformation, the Ramberg-Osgood Stress–strain relation for the plate material, and the Ritz method for the bifurcation Buckling analysis. The interaction curves of the plastic uniaxial Buckling Stress and the plastic shear Buckling Stress for thin and thick rectangular plates are presented for various aspect ratios. The effect of transverse shear deformation is examined by comparing the interaction curves obtained based on the Mindlin plate theory and the classical thin plate theory.
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Plastic Buckling of rectangular plates under combined uniaxial and shear Stresses
2006Co-Authors: Chien Ming Wang, Tun Myint AungAbstract:This paper deals with the plastic Buckling of rectangular plates under uniaxial compressive and shear Stresses. In the prediction of the plastic Buckling Stresses, we have adopted both the incremental theory (IT) and deformation theory (DT) of plasticity for capturing the inelastic behavior, the Mindlin plate theory (allowing for the effect of transverse shear deformation) for modelling the plate, the Ramberg-Osgood Stress strain relation for the plate material, and the Ritz method for the Buckling analysis. The interaction curves of the plastic uniaxial Buckling Stress and the plastic shear Buckling Stress for thin and thick rectangular plates are presented for various aspect ratios. The effect of transverse shear deformation is examined by comparing the interactions curves obtained based on the Mindlin plate theory and the classical thin plate theory. The normalized interaction curves based on DT are found to be bounded by Peters' interaction formula and the elastic interaction formula.
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PLASTIC Buckling OF SIMPLY SUPPORTED, POLYGONAL MINDLIN PLATES
Journal of Engineering Mechanics, 2004Co-Authors: Chien Ming WangAbstract:This paper is concerned with the plastic Buckling of Mindlin plates of polygonal plan shape and whose straight edges are simply supported. The plates are subjected to a uniform in-plane compressive Stress. Two well-known competing theories of plasticity are considered here: the incremental theory of plasticity (with the Prandtl-Reuss constitutive relations) and the deformation theory of plasticity (with the Hencky constitutive relation). Based on an analogy approach, the plastic Buckling Stresses of such Mindlin plates are expressed in terms of their corresponding elastic Buckling Stresses of Kirchhoff (classical thin) plates, albeit in a transcendental form. Using this Buckling Stress relationship and the readily available elastic Buckling solutions, one may deduce the plastic Buckling Stresses of the corresponding Mindlin plates. Tabulated herein are some Buckling Stress factors for various polygonal shaped plates with material properties defined by the Ramberg-Osgood relation.
Debraj Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Buckling analysis of cylindrical thin-shells using strain gradient elasticity theory
Meccanica, 2017Co-Authors: N. M. Anoop Krishnan, Debraj GhoshAbstract:The stability problem of cylindrical shells is addressed using higher-order continuum theories in a generalized framework. The length-scale effect which becomes prominent at microscale can be included in the continuum theory using gradient-based nonlocal theories such as the strain gradient elasticity theories. In this work, expressions for critical Buckling Stress under uniaxial compression are derived using an energy approach. The results are compared with the classical continuum theory, which can be obtained by setting the length-scale parameters to zero. A special case is obtained by setting two length scale parameters to zero. Thus, it is shown that both the couple Stress theory and classical continuum theory forms a special case of the strain gradient theory. The effect of various parameters such as the shell-radius, shell-length, and length-scale parameters on the Buckling Stress are investigated. The dimensions and constants corresponding to that of a carbon nanotube, where the length-scale effect becomes prominent, is considered for this investigation.
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A novel method for studying the Buckling of nanotubes considering geometrical imperfections
Applied Physics A, 2014Co-Authors: N. M. Anoop Krishnan, Debraj GhoshAbstract:Buckling of nanotubes has been studied using many methods such as molecular dynamics (MD), molecular mechanics, and continuum-based shell theories. In MD, motion of the individual atoms is tracked under applied temperature and pressure, ensuring a reliable estimate of the material response. The response thus simulated varies for individual nanotubes and is only as accurate as the force field used to model the atomic interactions. On the other hand, there exists a rich literature on the understanding of continuum mechanics-based shell theories. Based on the observations on the behavior of nanotubes, there have been a number of shell theory-based approaches to study the Buckling of nanotubes. Although some of these methods yield a reasonable estimate of the Buckling Stress, investigation and comparison of buckled mode shapes obtained from continuum analysis and MD are sparse. Previous studies show that the direct application of shell theories to study nanotube Buckling often leads to erroneous results. The present study reveals that a major source of this error can be attributed to the departure of the shape of the nanotube from a perfect cylindrical shell. Analogous to the shell Buckling in the macro-scale, in this work, the nanotube is modeled as a thin-shell with initial imperfection. Then, a nonlinear Buckling analysis is carried out using the Riks method. It is observed that this proposed approach yields significantly improved estimate of the Buckling Stress and mode shapes. It is also shown that the present method can account for the variation of Buckling Stress as a function of the temperature considered. Hence, this can prove to be a robust method for a continuum analysis of nanosystems taking in the effect of variation of temperature as well.
Kim J.r. Rasmussen - One of the best experts on this subject based on the ideXlab platform.
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design of slender angle section beam columns by the direct strength method
Journal of Structural Engineering-asce, 2006Co-Authors: Kim J.r. RasmussenAbstract:This paper is concerned with the application of the direct strength method to equal angle section beam-columns with locally unstable legs. In contrast to existing design methods, which independently determine the compression and bending capacities and use an interaction equation to combine these, the direct strength method determines the elastic local Buckling Stress for the actual Stress distribution resulting from the combined action of compression and bending, and incorporates the elastic Buckling Stress into a direct strength equation for beam-columns. In applying the method to equal leg angles, the torsional Buckling mode is ignored when determining the overall Buckling capacities, since it is accounted for through the local Buckling mode, and the shift of the effective centroid is incorporated as an additional loading eccentricity. The shift in the effective centroid resulting from local Buckling is determined from the actual Stress distribution, as obtained using Stowell's classical solution, in place of an effective cross section. The predicted strengths are conservative compared to tests on slender equal angle columns, and are shown to accurately predict the variation in load with applied loading eccentricity.
Osama Bedair - One of the best experts on this subject based on the ideXlab platform.
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novel design procedures for rectangular hollow steel sections subject to compression and major and minor axis bending
Practice Periodical on Structural Design and Construction, 2015Co-Authors: Osama BedairAbstract:AbstractThis paper presents novel and cost-effective design procedures for rectangular hollow steel sections (RHSS) subject to combined compression and major and minor axis bending. Although this loading pattern is very common in practice, very little research has addressed the local stability of RHSS for this loading condition. Furthermore, current North American and European design provisions ignore rotational and lateral restraints in evaluating local web Buckling Stress of RHSS. This paper provides an analytical closed-form expression to compute web Buckling Stress with rotational and lateral restraints under compression and biaxial bending. The accuracy of the expression is compared numerically and with existing expressions for the limiting simply supported condition. The maximum difference was found to be less than 2%. The behavior of standard RHSS is also reexamined. Guidelines are also provided for practicing engineers and steel fabricators to optimize the design of RHSS.
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Design expression for web shear Buckling of box sections by accounting for flange restraints
Journal of Constructional Steel Research, 2015Co-Authors: Osama BedairAbstract:Abstract This paper presents a new analytical expression for computing the web shear Buckling Stress with partial flange rotational restraints. The derived expression is suitable to be used in practice for hand calculation and avoids excessive efforts required to perform numerical analysis using finite element or finite strip methods. The material savings resulting from using the proposed design expression are also illustrated. Current design provisions ignore the flange rotational restraints effect in determining the web shear Buckling Stress for box sections. A comparison is made with AISI, CSA-S16, Eurocode 3 and AASHTO provisions for the limiting conditions. It is also shown that the shear Buckling Stress may vary by 40% with the current design expressions. Numerical validation of the proposed expression with semi-analytical finite strip method is also presented. The influence of the flange geometric properties on the web Buckling Stress is also highlighted.
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A Generalized Approach to the Local Stability of Stiffened Plates: Part I–Mathematical Formulation
1994Co-Authors: Osama Bedair, Archibald N. SherbourneAbstract:The paper describes a generalized approach for the determination of the Buckling Stress of stiffened plates under combination of uniform biaxial compression, in-plane bending and shear Stress. The plate is treated as partially restrained against rotation and in-plane translation. In the first stage, the plate is considered as infinitely long with idealized Buckling modes and the energy method is used to formulate the Buckling factor, K for this condition. The Buckling Stress is then computed using mathematical programming by finding the combination of parameters in the idealized Buckling mode that minimizes K. Modification factors are then suggested to compute the Buckling Stresses for plates of finite lengths.
Enrique Mirambell - One of the best experts on this subject based on the ideXlab platform.
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A new developed expression to determine more realistically the shear Buckling Stress in steel plate structures
Journal of Constructional Steel Research, 2008Co-Authors: I. Estrada, Esther Real, Enrique MirambellAbstract:Abstract This paper summarises and presents main results of an in-depth numerical analysis dealing with the shear Buckling resistance of stainless steel plate girders. The studies conducted have permitted the development of a simple design expression to determine the critical shear Buckling Stress in steel web panels. This expression takes into account the effects of the material nonlinearity together with the actual boundary conditions of the web panel given by the geometry of the plate girder by two defined parameters: η and k rss , which is the shear Buckling coefficient. Expressions given to obtain η will quantify mainly the effect of the material nonlinearity whereas the proposed analytical expression of k rss will reproduce principally the influence of the real boundary conditions in a web panel.
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Shear Buckling Stress in stainless steel plate girders
Fourth International Conference on Advances in Steel Structures, 2005Co-Authors: I. Estrada, Esther Real, Enrique MirambellAbstract:Publisher Summary The chapter discusses shear Buckling Stress in stainless steel plate girders. The main advantage of stainless steel is its natural corrosion resistance which makes it one of the most durables materials in construction, as well as a material with excellent aesthetics and ease of maintenance. The use of stainless steel in construction is becoming increasingly common but due to the lack of knowledge about the actual response of the material, its use as a structural resisting material remains limited. As a relatively new structural material, there are no fully developed design rules included in the standards and in the design manuals that could make a full competitive design of stainless steel structures possible. The chapter presents two series of numerical analyses conducted in panels under a shear to evaluate the influence of the material non-linearity and to investigate the effects of geometric parameters of a stainless steel plate girder on the boundary conditions of the web panel. Results obtained permit to determine shear Buckling Stress more realistically for a stainless steel webs.
