• Steel and Composite Structures
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• 제44권4호
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• pp.489-502
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• 2022

The stiffeners, also known as ribs, are utilized to increase the resistance of T-stubs. The author's previous studies showed that stiffeners can increase plastic capacity by an average of 1.71 times. A combined experimental and numerical study was undertaken to examine the effects of the stiffener configuration on the behavior of T-stubs. A total of 20 stiffened T-stubs where the shape and angle of stiffeners were considered as the main parameters were tested under monotonic loading. Rectangular, triangular and AISC types of stiffener were tested under monotonic loading. The experimental results indicated that when the height of the stiffener is equal to or higher than the length of the stiffener, the shape of the stiffener does not have an influence on the behavior. A numerical study using the finite element tool ABAQUS was carried out in order to further investigate the effects of the stiffener shapes. In this case, the height is considered less than the length of the stiffener. Moreover, the shape of the stiffeners was investigated with the different thicknesses of the stiffener. The simulation findings revealed that when the height of the stiffener is less than the length of the stiffener, the shape of the stiffener significantly affects the plastic capacity. Based on the numerical and experimental results, it is recommended to use the triangular shape of the stiffener when height is equal to or higher than the length of the stiffener while it is recommended to utilize the rectangular shape of the stiffener when height is less than the length of the stiffener.

• Steel and Composite Structures
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• 제29권5호
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• pp.681-688
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• 2018

In this paper, buckling load of edge stiffened composite plates is assessed. The effect of stiffener edge size, circular hole, and the fiber orientation angle on buckling behavior of composite plates under uni-axial compressive load is investigated. This paper includes two parts as experimental and numerical studies. L-shape composite plates are manufactured in three different layups. Then the buckling loads are experimentally determined. Subsequently, by using the numerical simulation, the size variation effects of stiffener edge and circular cutout on the plate buckling loads are analyzed in five different layups. The results show that cutout size, stiffener edge height and fiber orientation angle have important effects on buckling load. In addition, there is an optimum height for stiffener edge during different conditions.

• International Journal of Korean Welding Society
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• 제1권1호
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• pp.51-57
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• 2001

Effect of the joint details on the stress distribution over a slot structure has been studied in order to improve its fatigue life using a finite element analysis. The joint details of interest are the radius and height of scallop at the stiffener as well as the mis-alignment between the stiffener and longitudinal member. For a slot structure currently used, the stiffener heel is subjected to the maximum stress for a given external load, where is a potential fatigue crack initiation site. The stresses at the stiffener heel and toe decrease both by increasing the scallop radius and more significantly by increasing the mis-alignment while no notable effect of the scallop height on it is appreciated. A proper combination of these factors makes it possible to reduce the stresses at the stiffener heel and In, theoretically, more than 50%. This is attributed to the modification of the stress distribution over the slot structure including the transition of the maximum stressed region from the stiffener heel to the slot surface of the transverse web. Such then results in a g[eat improvement of the fatigue life of the slot structure.

• 한국레이저가공학회지
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• 제1권1호
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• pp.11-17
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• 1998

The electron beam welding system has the advantages of the high power density, narrow welding section, and small thermal distortion of a workpiece. Recently, the electron beam welding system is widely used to the airplane engineering, nuclear power plant, and automobile industry. In the present paper, the structural analyses on the vacuum chamber of the electron beam welding system are performed by the F.E.M. analysis. The stiffening characteristics on the geometric shape, stiffener height and stiffener span are investigated. The deflection of the stiffened vacuum chamber under pressure is minimized by longitudinal and transverse stiffeners which are continuous in both direction.

• 해양환경안전학회지
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• 제14권1호
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• pp.89-93
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• 2008

보강판은 선박이나 해양구조물에서 폭넓게 사용되고 있는 기본적인 강도 부재이다. 이러한 보강판은 선박의 갑판부, 선측부, 선저부에 흔히 사용되고 있다. 보강판은 보강재가 어느 한 방향으로 또는 양방향으로 구성되어 있으며 후자에 대해서 보통 그릴리지라고 한다. 보강판의 좌굴 및 소성붕괴는 선각거더의 파손 원인이 되므로 좌굴 및 최종강도가 정확하게 규명할 필요가 있다. 본 연구에서는 범용유한요소해석코드인 ANSYS를 이용하여 좌굴 및 좌굴 후 거동에 대한 평가를 수행하고 보강재 치수변화, 수압의 영향을 고려하여 압축최종강도에 대해 해석 수행하였다.

• Composites Research
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• 제29권5호
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• pp.231-235
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• 2016

본 연구에서는 동일한 구조의 모자형 보강재를 이용하여 일체형 동시접착 구조의 보강패널시편을 제작하였다. 일반적인 동시접착 보강패널 시편과 탄소에폭시 복합재를 이용하여 제작된 카울플레이트(Caul Plate)를 적용한 동시접착 보강패널 시편의 2가지 형태 시편을 제작하였으며 일반 동시접착 보강패널 시편에서는 패널 상에서 보강재가 적용되지 않은 부위가 적용된 부위보다 더 두꺼운 패널 두께를 가지고 그 연결부위에는 0.61 mm 높이 및 3.29 mm 길이의 플라이웨이브 현상이 나타났다. 카울플레이트가 적용된 보강패널 시편에서는 보다 균일한 압력 전달로 인하여 0.22 mm 높이와 1.37 mm 길이의 완화된 웨이브 현상을 보이면서 약 50% 이상 개선된 결과를 얻을 수 있었다.

• 한국강구조학회 논문집
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• 제20권1호
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• pp.9-20
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• 2008

강박스거더교 다이아프램부에 있어서 경제적이고 합리적인 설계가 요망되어 진다. 본 연구에서는 시공중인 4경간 강박스거더교에서 콘크리트 상판 타설 시와 차량재하 시에 응력을 측정한다. 측정 결과는 지점부 다이아프램부와 중앙부에서 응력분배를 연구하기 위하여 분석된다. 다이아프램부 수직보강재의 높이별 응력과 이와 같은 높이의 다이아프램부 응력을 정리하고, 이들 결과를 분석하여 적정 수직보강재 길이의 효율성을 판단한다. 또한 다이아프램부 3조의 수직보강재 각각의 응력을 분석하고, 콘크리트 경화 후 차량 재하 시와 시에 따른 응력비를 산출하여 다이아프램부 설계합리화 연구의 기본 자료로 수립하고자 한다.

• Smart Structures and Systems
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• 제26권6호
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• pp.703-720
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• 2020

This paper investigates the safety of the wind turbine blade against excessive deformation. For this purpose, the performance of the blade in the along-wind direction is improved by longitudinal stiffener made of shape memory alloy. The rationale behind the selection of this smart material is due to its ability to offer excellent thermo-mechanical behaviour at low strain. Here, Liang-Roger model is adopted for vibration control, and the super-elastic effects are utilised for blade stiffening. Turbulent wind fields are generated at the hub height using TurbSim and the corresponding loads are evaluated using blade element momentum theory. An efficient switching algorithm is developed along with performance curves that enable the designer to select an optimal mode of heating depending upon the operational scenario. Numerical results presented in this paper clearly demonstrate the performance envelope of the proposed stiffener and its influence on the reliability of the blade.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.227-234
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• 2001

The lifting and lowering supports method was recently developed in steel box girder bridge. It has many advantages by lifting and lowering of inner supports and filled concrete. This method reduces an amount of steel and height of girders. It is one of the methods used to effectively increase the use of structural material. However, if there is too much lifting of inner supports, it is possible to cause buckling of the compression flange or web panel. Therefore it needs a proper number of longitudinal and transvers stiffener.

• Steel and Composite Structures
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• 제21권1호
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• pp.137-156
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• 2016

Due to excellent advantages such as better illuminative effects, considerable material savings and ease and rapidness of construction, the bolted ball-cylinder joint which is a new type joint system has been proposed in space truss structures. In order to reveal more information and understanding on the behaviour of bolted ball-cylinder joints, full-scale experiments on eight bolted ball-cylinder joint specimens were conducted. Five joint specimens were subjected to axial compressive force, while another three joint specimens were subjected to axial tensile force. The parameters investigated herein were the outside diameter of hollow cylinders, the height of hollow cylinders, the thickness of hollow cylinders, ribbed stiffener and axial force. These joint specimens were collapsed by excessive deformation of hollow cylinders, punching damage of hollow cylinders, evulsion of bolts, and weld cracking. The strain distributions on the hollow cylinder opening were mainly controlled by bending moments. To improve the ultimate bearing capacity and axial stiffness of bolted ball-cylinder joints, two effective measures were developed: (1) the thickness of the hollow cylinder needed to be thicker; (2) the ribbed stiffener should be adopted. In addition, the axial stiffness of bolted ball-cylinder joints exhibited significant non-linear characteristics.