• Steel and Composite Structures
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• 제18권4호
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• pp.1023-1044
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• 2015

Concrete-filled tubes (CFT), formed by an outer steel tube filled with plain or reinforced concrete inside, have been increasingly used these recent decades as columns or beam-columns, especially for tall buildings in seismic areas due to their excellent structural response. This improved behavior is derived from the effect of confinement provided by the tube, since the compressive strength of concrete increases when being subjected to hydrostatic pressure. In circular CFTs under compression, the whole tube is uniformly tensioned due to the radial expansion of concrete. Contrarily, in rectangular and square-shaped CFTs, the lateral flanges become subjected to in-plane bending derived from this volumetric expansion, and this fact implies a reduction of the confinement effect of the core. This study presents a numerical analysis of different configurations of CFT stub columns with inner stiffening plates, limited to the study of the influence of these plates on the compressive behavior without eccentricity. The final purpose is to evaluate the efficiency in terms of strength and ductility of introducing stiffeners into circular and square CFT sections under large deformation axial loading.

• 대한기계학회논문집
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• 제18권6호
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• pp.1520-1534
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• 1994

A new analytical method for the prediction of the buckling behavior of laminated plates consisting of layers having different properties in tension and compression, so called bimodulus, is proposed in this paper. Buckling analysis of bimodular composite laminated paltes are performed with the results reduced from plate bending analysis. The governing equations of bimodular plates are based on the first shear deformation theory. As a case study, bending and buckling of simply supported, multilayered, symmetric, antisymmtric, and specially orthotropic laminates under uniformly distributed lateral load for bending analysis and in-plane load for buckling are considered. The results of the bending analysis are compared with the previous papers. Then, the fundamental critical buckling loads and buckling modes are calculated for the various bimodular composite rectangular thin plates.

• Steel and Composite Structures
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• 제22권6호
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• pp.1417-1443
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• 2016

Cellular and castellated steel beams are used to obtain higher stiffness and bending capacity using the same weight of steel. In addition, the beam openings may be used as a pass for different mechanical fixtures such as ducts and pipes. The aim of this study is to investigate the effect of different parameters on both elastic and inelastic critical buckling stresses of steel web plates with openings. These parameters are plate aspect ratio; opening shape (circular or rectangular); end distance to the first opening; opening spacing; opening size; plate slenderness ratio; steel grade; and initial web imperfection. The web/flange interaction has been simplified by web edge restraints representing simply supported boundary conditions. A numerical parametric study has been performed through linear and nonlinear finite element (FE) models, where the FE results have been verified against both experimental and numerical results in the literature. The web plates are subject to in-plane linearly varying compression with different loading patterns, ranging from uniform compression to pure bending. A buckling stress modification factor (${\beta}$-factor) has been introduced as a ratio of buckling stress of web plate with openings to buckling stress of the corresponding solid web plate. The variation of ${\beta}$-factor against the aforementioned parameters has been reported. Furthermore, the critical plate slenderness ratio separating elastic buckling and yielding has been identified and discussed for two steel grades of DIN-17100, namely: ST-37/2 and ST-52/3. The FE results revealed that the minimum ${\beta}$-factor is 0.9 for web plates under uniform compression and 0.7 for those under both compression and tension.

• Steel and Composite Structures
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• 제11권2호
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• pp.131-147
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• 2011

The aim of this work is to provide some insights into the elasto-plastic behaviour of plate girder web square and rectangular panels with centred and eccentric holes under both compression and in-plane bending moment. The numerical study was validated comparing the numerical results obtained for one simple steel plate configuration with the corresponding experimental results, obtained at the University of Padova, observing the influence of the initial out-of-plane imperfections on the force vs. displacement relationship and ultimate strength. Once validated the numerical approach, the effect of bending moment on the stability of the plate is studied and some differences with respect to the uniform compression load case are shown. The influence of dimension and position of the hole, the plate aspect ratio and the steel grade on elasto-plastic behaviour is observed. Some indications regarding the critical slenderness (at which transition from elastic to plastic collapse occurs) are given for square and rectangular plates with symmetric and eccentric holes having small, medium and large diameter.

• Structural Engineering and Mechanics
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• 제4권4호
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• pp.383-396
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• 1996

In this paper, the behavior of plates partially restrained against rotation under stress gradient is investigated. As a first stage, an energy formulation is presented to model this boundary condition and a general expression is derived for the prediction of the elastic buckling of the plate under this general loading condition. The accuracy of the derived expression is compared numerically using the Galerkin method with other available data for the two limiting conditions of rotationally free and clamped boundaries. Results show that the prediction is within a 5% difference. The influence of rotational restraint and stress gradient upon the buckling load and the associated buckling mode is investigated. Numerical results show sensitivity of the buckling mode to the degree of rotational restraint and the variation of the buckling load with the stress gradient.

• 대한기계학회논문집A
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• 제31권11호
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• pp.1124-1130
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• 2007

This paper presents a new way for fabricating sandwich plates with tetrahedral truss cores. The tetrahedral truss cores are manufactured through metal expanding and bending process and then brazed with solid face sheets. The properties of sandwich plates with the tetrahedral truss cores composed of a wrought steel SS41 under compression and shear loading have been investigated. Good agreement is observed between the measured and predicted peak strengths. Comparisons with normalized compressive strength for other cellular metals have indicated that the tetrahedral truss structures outperform aluminum open cell forms and woven core sandwich plates.

• Steel and Composite Structures
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• 제29권3호
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• pp.379-389
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• 2018

In this research, the explicit closed-form local buckling solution of steel plates in contact with concrete, with both loaded and unloaded edges elastically restrained against rotation and subjected to eccentric compression is presented. The Rayleigh-Rize approach is applied to establish the eigenvalue problem for the local buckling performance. Buckling shape which combines trigonometric and biquadratic functions is introduced according to that used by Qin et al. (2017) on steel plate buckling under uniform compression. Explicit solutions for predicting the local buckling stress of steel plate are obtained in terms of the rotational stiffness. Based on different boundary conditions, simply yet explicit local buckling solutions are discussed in details. The proposed formulas are validated against previous research and finite element results. The influences of the loading stress gradient parameter, the aspect ratio, and the rotational stiffness on the local buckling stress resultants of steel plates with different boundary conditions were evaluated. This work can be considered as an alternative to apply a different buckling shape function to study the buckling problem of steel plate under eccentric compression comparing to the work by Qin et al. (2018), and the results are found to be in consistent with those in Qin et al. (2018).

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1996년도 The Korean Institute of Navigation 1996년도 한·중 국제학술 심포지움 및 추계학술발표회 논문집
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• pp.95-110
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• 1996

High Tensile Steel enables to reduce the plate thickness comparing to the case when Mild Steel is used. From the economical view point this is very preferable since the reduction in the hull weight. However to use the High Tensile Steel effectively the plate thickness may become thin so that the occurrence of buckling is inevitable and design allowing plate buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling, buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling the flexural rigidity of the cross section of a ship's hull also decreases. this may lead to excessive deflection of the hull girder under longitudinal bending. In these cases a precise estimation of plate's behavior after buckling is necessary and nonlinear analysis of isolated and stiffened plates is required for structural system analysis. In this connection this paper discusses nonlinear behaviour of thin plate under thrust. Based on the analytical method elastic large deflection analysis of isolated plate is perform and simple expression are derived to evaluate the inplane rigidity of plates subjected to uniaxial compression.

• Journal of Advanced Marine Engineering and Technology
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• 제23권4호
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• pp.565-573
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• 1999

Hihg Tensile Steel enables to reduce the plate thickness comparing to the case when Mild Steel is used. From the economical view points this is very preferable since the reduction in the hull weight. however to use the High Tensile Steel effectively the plate thickness may become thin so that the occurrence of buckling is inevitable and design allowing plate buckling may be necessary. If the inplane stiffness of the plating decreases due to buckling the flexural rigidity of the cross sect6ion of a ship's hull also decreases. This may lead to excessive deflection of the hull girder under longitudinal bending. In these cases a precise estimation of plate's behavior after buckling is necessary and nonliner analysis of isolated and stiffened plates is required for structural sys-tem analysis. In this connection this paper discusses nonlinear behaviour of thin plate under thrust. Based on the analytical method elastic large deflection analysis of isolated plate is perform and simple expression are derived to evaluated the inplane rigidity of plates subjected to uniaxial compression.

• 대한조선학회논문집
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• 제29권1호
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• pp.93-102
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• 1992

본 논문에서는 종굽힘하에서 이중선각구조선박의 최종굽힘강도와 피로강도에 대한 신뢰성평가를 다루었다. 최종굽힘강도는 beam-column approach의 개념을 이용하여 구하였고, 보강판의 응력-변형도 곡선들은 소성힌지의 개념을 이용하여 유도하였다. 피로강도는 피로손상에 대한 것만을 고려하였고, 이를 위해 Miner의 손상식을 이용하였다. 갑판에서 가능한 여러 연결부 형태에 대해 그 피뢰신뢰성을 추정하였고 또한 굽힘에 의한 파괴와 피로에 의한 파괴를 동시에 고혀하는 일종의 Series System에 대한 신뢰성을 평가를 하였다.