• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.91-94
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• 2001

This paper presents the analytical investigation pertaining to the local buckling behavior of orthotropic channel section compression members stiffened with unsymmetric stiffeners at its free edges. In the analysis, tile edge stiffener is modeled as a beam element or a plate element. The result of both cases is presented in graphical form so that the effects of edge stiffeners on the local buckling strength of edge stiffened channel section member can be found.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.78-86
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• 2005

In this study, cantilever cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Three models by load conditions are considered. Model A, B and C are loaded by point load at the free edge, line load and external pressure respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced more than 50% for Model A, about $20{\sim}30%$ for Model B by appropriate edge-stiffeners.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.5-8
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• 2000

This paper presents the analytical investigation pertaining to the local buckling behavior of orthotropic open section thin-walled compression members with asymmetric edge stiffeners. In the analysis, 3 different cases of the second moment of inertia are considered to find the asymmetric edge stiffener effect on the local buckling strength. The analytical study results are presented in the graphical form so that the edge stiffener effects on the local buckling strength can be easily found.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.2
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• pp.47-54
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• 2012

In this study, composite laminate cantilever type cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Two models by load conditions are considered. Load type A and B are loaded by point load at the free edge and line load respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced minimum 30% by appropriate edge-stiffeners.

• Journal of the Korean Society of Safety
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• v.22 no.3 s.81
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• pp.45-50
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• 2007

In this study, reinforcing effects of umbrella-type shell roofs structures such as stadium, exhibition, auditorium and museum are analyzed. Umbrella-type shell roofs treated in this study are practical shapes of conical shells. The objective of this study is to analyze reinforcing effects of umbrella-type shell roofs with stiffeners. Various locations of stiffeners, that is, edge ring A, B, center ring, junction stringer and center stringer are presented and the effects of reinforcement is examined. Also, the reduction effects of roofs thickness by stiffeners are examined. It is shown that the thickness of roofs can be reduced about $20{\sim}30%$ by junction stringer and more than 60% by edge ring A.

• Advances in Computational Design
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• v.1 no.2
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• pp.207-220
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• 2016

The aim of this study is to investigate the effect of stiffened element and edge stiffener in the behaviour and flexural strength of built-up cold-formed steel beams. An experimental and analytical analysis of CFS channel sections in four different geometries is conducted, including simple channel sections, a stiffened channel section with or without edge stiffeners. Nonlinear finite element models are developed using finite element analysis software package ANSYS. The FEA results are verified with the experimental results. Further, the finite element model is used for parametric studies by varying the depth, thickness, and the effect of stiffened element, edge stiffener and their interaction with compression flanges on stiffened built-up cold-formed steel beams with upright edge stiffeners. In addition, the flexural strength predicted by the finite element analysis is compared with the design flexural strength calculated by using the North American Iron and Steel Institute Specifications for cold-formed steel structures (AISI: S100-2007) and suitable suggestion is made.

• Composites Research
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• v.14 no.4
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• pp.1-7
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• 2001

This paper presents the results of an analytical investigation pertaining to the elastic local buckling behavior of asymmetric edge stiffened orthotropic open section structural member under uniform compression. The asymmetric edge stiffener is considered as a beam element neglecting its torsional rigidity. We suggested the analytical model of asymmetric edge stiffeners which is composed of a strip of flange plate, equal width of edge stiffener, and a plate attached at the flange end, and computed the moment of inertia of the stiffener about an axis through the centroid of the ensuing cross-section. Using the derived equation, the local buckling coefficients of asymmetrically edge stiffened orhtotropic I-section columns are predicted and the results are presented in a graphical form.

• Structural Engineering and Mechanics
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• v.42 no.6
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• pp.883-897
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• 2012

Cold-formed channel sections are used in a variety of applications in which they are required to absorb deformation energy. This paper investigates the collapse behaviour and energy absorption capability of cold-formed steel channels with flange edge stiffeners under large deformation major-axis bending. The Yield Line Mechanism technique is applied using the energy method, and based upon measured spatial plastic collapse mechanisms from experiments. Analytical solutions for the collapse curve and in-plane rotation capacity are developed, and used to model the large deformation behaviour and energy absorption. The analytical results are shown to compare well with experimental values. Due to the complexities of the yield line model of the collapse mechanism, a simplified procedure to calculate the energy absorbed by channel sections under large bending deformation is developed and also shown to compare well with the experiments.

• Bulletin of the Society of Naval Architects of Korea
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• v.20 no.4
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• pp.9-16
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• 1983

When the perforated panels are under in-plane shear loads, shear buckling analysis is also necessary because of the presence of stress concentration around holes. To constrain it, we need some reinforcement. The methods of reinforcement are attaching doubler around hole and stiffeners in the arbitary directions. In this paper, two kinds of methods mentioned above are investigated, it is also clarified that which of the two is the more effective reinforcement. For the sake of convenience those arbitary directions were selected parallel ($90^{\circ}$) and oblique ($135^{\circ}$) to the edge. From the results of the above investigation, following conclusion was obtained. In case of parallel stiffeners, doubler reinforcement gives higher buckling strength than stiffener, however, in case of oblique stiffeners, doubler reinforcement gives higher buckling strength than doubler when the external load direction is known.

• Steel and Composite Structures
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• v.42 no.6
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• pp.791-804
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• 2022

As a type of semi-rigid connection, the top and seat angle connections are popular in current structures owing to their good cyclic performance and simple erection. However, their stiffness and load bearing capacity are relatively insufficient. This study proposes two strengthening methods to further increase the stiffness and strength of bolted-angle joints while maintaining satisfactory energy dissipation capacity (EDC) and ductility. Cyclic loading tests were conducted on six joint specimens with different strengthened angle components. Based on the test results, the influence of the following important factors on the cyclic behavior of steel joint specimens was investigated: the position of the rib stiffeners (edge rib stiffeners and middle rib stiffener), steel strength grade of rib stiffeners (Q345 and Q690), and additional stiffeners or not. In addition, the finite element models of these specimens were built and validated through a comparison of experimental and numerical results. The stiffness and bearing capacity of the bolted-angle joints could be improved significantly by utilizing the novel strengthened joints proposed in this study. Moreover, this can be achieved with almost no increase in the amount of steel required, and the EDC of this joint could also satisfy the requirements of seismic codes from various countries.