• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.33-43
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• 1996

In this paper, collapse test of thin-walled structures, which are widely used in the vehicle members is carried out to observe the dependence of cross-sectional forms and materials on the absorbed energy in the viewpoint of crashworthiness. Also, specimens consist of two kinds (Al, CFRP) with various thickness. Comparisons of circular specimens are made to find characteristics of the different specimens on the absorption ability according to specimen thickness and materials.

• Structural Engineering and Mechanics
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• v.48 no.1
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• pp.77-91
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• 2013

The paper presents the formulation of 3-nodal line semi-analytical Mindlin-Reissner finite strip in the buckling analysis of thin-walled members, which are subjected to arbitrary loads. The finite strip is simply supported in two opposite edges. The general loading and in-plane rotation techniques are used to develop this finite strip. The linear stiffness matrix and the geometric stiffness matrix of the finite strip are given in explicit forms. To validate the proposed model and study its performance, numerical examples of some thin-walled sections have been performed and the results obtained have been compared with finite element models and the published ones.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.86-91
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• 2008

The structural members must be designed to control characteristics of energy absorption for protecting passengers in a car accident. Study on collapse characteristics of structural member is currently conducted in parallel with other studies on effective energy absorption capacity of structural members with diverse cross-sectional shapes and various materials. This study concerns the crashworthiness of the widely used vehicle structural members, square thin-walled tubes, which are excellent in the point of the energy absorption capacity. The absorbed energy, mean collapse load and deformation mode were analyzed for side member which absorbs most of the collision energy. To predict and control the energy absorption, controller is designed in consideration of its influence on height, thickness and width ration in this study. The absorbed energy and mean collapse load of square tubes were increased by $15{\sim}20%$ in using the controller, and energy absorbing capability of the specimen was slightly changed by change of the high controller's height.

• Structural Engineering and Mechanics
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• v.2 no.3
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• pp.269-284
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• 1994

The analysis and tests of thin-walled channel frames including nonlinear flexible or semi-rigid connection behaviour is presented. The semi-rigid connection behaviour is modelled using a mathematical approximation of the connection flexibility-moment relationship. Local instability such as local buckling and torsional flexural buckling of the member are included in the analysis. The full response of the frame, up to the collapse load, can be predicted. Experimental investigation was carried out on a series of simple double storey symmetrical frames with the purpose of verifying the accuracy and validity of the analysis. Agreement between the theoretical and experimental results is acceptable. The investigation also shows that connection flexibility and local instability such as local buckling and torsional flexural buckling can affect the behaviour and strength of thin-walled frames significantly. The results can also provide further insight into the advanced study of practical structures where interaction between flexible connections and phenomenon associated with thin-walled members are present.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.65-72
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• 1994

Collapse characteristics of thin-walled hatted section tubes are investigated. The square section members with flanges are substituted by the equivalent rectangular tube. The stiffening effects of flanges are transformed to the restraining plate with the equivalency of buckling strength. The square tubes of single-hatted and double-hatted sections are investigated. The double-hatted section members show symmetric and antisymmetric crushing modes depending on the stiffness of flanges. The single-hatted section members show only symmetric modes. The bifurcation point of the compact crushing modes are investigated by experiments and shown almost same thickness-width ratio of the rectangular tubes. A large maximum crippling strength can be obtained by double-hatted section members with proper flange dimensions.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.2
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• pp.194-201
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• 2005

For engineers in the industry, this study considers a reliable and practical finite element modeling technique to estimate the behavior of closed thin-walled members with spot weldings. Dynamic and static experiments confirm that the technique - modeling the spot weldings with solid elements which have the adjusted rotational freedoms and fill the welding space - Yields satisfactory results. Numerical studies on the double hat-shaped members. adopting this modeling technique. show the effect of the spot welding Pitch and the spot welding location in the flange on the stiffness of the members Using the principal stiffness and newly proposed GSPI(global stiffness performance index), we also carefully examine how the spot welding curvature, and sectional shape, etc.. synthetically influence the stiffness of a real excavator pillar in the field.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.647-657
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• 2011

This paper describes the moment capacity of flexural members with local buckling based on a series of FE and experiment results. Thin-walled flexural members undergo local, lateral-torsional, or interactive buckling according to the section geometries and lateral boundary conditions. Flexural members with large width-to-thickness ratios in the flanges or the web may undergo local buckling before lateral-torsional buckling. Local buckling has a negative effect on the flexural strength based on the lateral-torsional buckling of flexural members. This phenomenon should be considered in the estimation of the flexural strength of thin-walled sections. Flexural members with various width-to-thickness ratios in their flanges and web were analyzed. Initial imperfections in the local buckling mode, and residual stresses, were included in the FE analyses. Simple bending moment formulae for flexural members were proposed based on the FE and test results to account for local and lateral-torsional buckling. The proposed bending moment formulae for the thin-walled flexural members in the Direct Strength Method use the empirical strength formula and the grosssection modulus. The ultimate flexural strengths predicted by the proposed moment formulae were compared with the AISC (2005), Eurocode3 (2003), and Korean Highway Bridge Design Specifications (2010). The comparison showed that the proposed bending moment formulae can reasonably predict the ultimate moment capacity of thin-walled flexural members.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.167-171
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• 2005

The thick open section composite beams are used extensively as load carrying members and stiffeners of structural elements. However, most of studies on thick composite beams are limited only to closed section beams. In this study, an open cross-section thick-walled composite beam model which includes coupled stiffness, transverse shear, and warping effects is suggested and the deflections associated with the thick-walled composite beams and thin-walled composite beams are obtained and compared with the finite element analysis results. The correlation between thin and thick walled composite beam was achieved for two different layup configurations which are the circumferentially asymmetric stiffness (CAS) and circumferentially uniform stiffness (CUS) beams.

• Structural Engineering and Mechanics
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• v.69 no.4
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• pp.417-426
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• 2019

Buckling is one of the major causes of failure in thin-walled plate members and the presence of cracks with different lengths and locations in such structures may adversely affect this phenomenon. This study focuses on the buckling stability assessment of centrally and non-centrally cracked plates with small-, intermediate-, and large-size cracks, and different aspect ratios as well as support conditions, subjected to uniaxial compression. To this end, numerical models of the cracked plates were created through singular finite element method using a computational code developed in MATLAB. Eigen-buckling analyses were also performed to study the stability behavior of the plates. The numerical results and findings of this research demonstrate the effectiveness of the crack length and location on the buckling capacity of thin plates; however, the degree of efficacy of these parameters in plates with various aspect ratios and support conditions is found to be significantly different. Overall, careful consideration of the aspect ratio, support conditions, and crack parameters in buckling analysis of plates is crucial for efficient stability design and successful application of such thin-walled members.

• Steel and Composite Structures
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• v.4 no.5
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• pp.367-384
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• 2004

A numerical model based on the finite element technique is adopted to investigate the behavior and strength of thin-walled I-section beam-columns. The model considers both the material and geometric nonlinearities. The model results were first verified against some of the currently available experimental results. A parametric study was then performed using the numerical model and interaction diagrams for the investigated beam-columns have been presented. The effects of the web depth-to-thickness ratio, flange outstand-to-thickness ratio and bending moment-to-normal force ratio on the ultimate strength of thin-walled I-section beam-columns were scrutinized. The interaction equations adopted for beam columns design by the NAS (North American Specifications for the design of cold formed steel structural members) have been critically reviewed. An equation for the buckling coefficient which considers the interaction between local buckling of the flange and the web of a thin-walled I-section beam-column has been proposed.