• 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.

• Journal of KSNVE
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• v.9 no.3
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• pp.485-492
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• 1999

The effects of boundary conditions on vibration characteristics for the ring stiffered composite cylindrical shells are investigated by theoretical and experimental method. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect are adopted to derive the frequency equation. In experiment, the impact exciting method is used to obtain the vibraton results. Five different boundary conditions: clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study.

• 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.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.6
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• pp.391-399
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• 2020

In this study, the behaviors of a suction cap shaped as an arch were analyzed using finite element models. The fundamental structural behaviors of both flat- and arch-type caps were compared, and the advantages of the arch-shaped cap were explained. Moreover, the effects of geometric parameters and stiffener arrangements on the stress and deformation of the arch-shaped caps were investigated by comparisons of the changes in the behaviors of the caps. Additionally, the effects of boundary condition at the edge of the cap were analyzed to study the interactions between the cap and cofferdam walls; these results were used to derive the fundamental structural design of stiffened arch caps. Unlike flat caps, the results showed that ring stiffeners could improve the structural behaviors of arch caps remarkably, while the contributions of the radial stiffeners to the structural behaviors of the caps are dependent on constraints at the edges of the caps.