• 한국항해항만학회지
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• 제31권3호
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• pp.235-245
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• 2007

선체의 갑판부와 선저부 그리고 해양구조물의 기본적인 구조는 보강판이다. 보강판넬은 한쪽방향으로 위치한 보강재 혹은 종/횡 방향으로 복잡하게 위치한 구조를 이루고 있으며, 후자의 모델을 그릴리지 구조라고 부른다 선체구조설계 단계에서 선박의 종강도 평가는 가장 중요한 항목이다. 일반적으로, 극심한 해상상태에 놓인 선박의 선저부에는 호깅조건에 의해 발생되는 횡모멘트에 기인하여 압축하중이 작용하게 되며, 이와 동시에 수압하중 작용으로 인한 국부휭모멘트가 작용된다. 본 논문에서는, 구조해석 결과의 검증을 위해서 여러 가지 해석프로그램 및 현재 사용되고 있는 선급룰과의 비교를 하여 횡하중의 영향에 따른 압축최종강도에 대해 분석하고, 여러 가지 설계변수를 변화하여, 각각의 영향을 검토하고, 최종적으로 조합하중 조건에서의 횡하중의 영향에 대해서 분석하였다. 본 연구에서 얻어진 결과들은 최종한계상태설계법에 기반을 두고, 조합하중이 작용하는 선체보강판의 구조강도 거동에 대해서 하중성분에 대한 관계를 고찰하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권5호
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• pp.583-595
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• 2018

Stiffened panels are widely used in naval architecture and ocean engineering, and knowledge about their dynamic behaviour represents important issue in the design procedure. Ordinary vibration analysis consists of natural frequencies and mode shapes determination and can be extended to forced response assessment, while the Structural Intensity (SI) analysis, assessing magnitude and direction of vibrational energy flow provides information on dominant transmission paths and energy distribution including sink positions. In this paper, vibrational energy flow in stiffened panels under harmonic loading is analyzed by the SI technique employing the finite element method. Structural intensity formulation for plate and beam element is outlined, and developed system combining in-house code and general finite element tool is described. As confirmed within numerical examples, the developed tool enables separation of SI components, enabling generation of novel SI patterns and providing deeper insight in the vibrational energy flow in stiffened panels, comparing to existing works.

• 한국해양공학회지
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• 제34권1호
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• pp.37-45
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• 2020

Unstiffened and stiffened cylindrically curved plates are often used in ship structures. For example, they can be found on a deck with a camber, a side shell at the fore and aft parts, and the circular bilge part of a ship structure. It is believed that such cylindrically curved plates can be fundamentally modelled using a portion of a circular cylinder. From estimations using cylindrically curved plate models, it is known that the curvature generally increases the buckling strength compared to a flat plate under axial compression. The existence of curvature is also expected to increase both the ultimate and buckling strengths. In the present study, a series of finite element analyses were conducted on stiffened curved plates with several varying parameters such as the curvature, panel slenderness ratio, and web height and type of stiffener applied. The results of numerical calculations on stiffened and unstiffened curved plates were examined to clarify the influences of such parameters on the characteristics of their buckling/plastic collapse behavior and strength under an axial compression.

• Journal of Advanced Marine Engineering and Technology
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• 제26권1호
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• pp.48-58
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• 2002

There is a purpose of this study for the proposal of the optimum technique utilized for the vibration design initial step. The stiffened plate structure for the ship hull is made for analysis model. To begin with, dynamic characteristics of stiffened plate structure is analysed using FEM. Main vibrational mode of the structure is decided in the analytical result of FEM. The simplified equation on the natural frequency of the main vibrational mode is induced. Next, sensitivity analysis is carried out using the simplified equation, and rate of change of dynamic characteristics is calculated. Then, amount of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of panel, cross section moment of stiffener and girder become a design variable. The validity of the optimization method using simplified equation is examined. It is shown that the result effective in the optimum modification for natural frequency of the stiffened plate structure.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.549-554
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• 2000

In this study, using linear and nonlinear deformation theories and by closed-form analysis and finite difference energy methods, respectively, various buckling load factors are obtained for stiffened laminated composite cylindrical panels with rectangular type longitudinal stiffeners and various longitudinal length to radius ratios, which are made from Carbon/Epoxy USN150 prepreg and are simply-supported on four edges under uniaxial compression, and then for them, buckling behavior design analyses are carried out by the nonlinear search optimizer, ADS

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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• pp.253-256
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• 1996

Stiffened panels are very frequently used for body structures of automobiles, air-crafts, submarines, etc., to suppress the vibration level. Swaging technique is the modification of the configuration of panel itself, and this is prefered to rib-like stiffeners because it does not change the total weight of structure. In this paper, the transmissibility of vibratory power through swage is investigated, where the swage is modeled as an incomplete circular ring, utilizing the well-known transfer matrix method. The power transmission and reflection coefficients of swaged panel are estimated and compared with experimental results.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.3-8
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• 2003

In this study, using linear and nonlinear deformation theories and by closed-form analysis and finite difference energy methods, respectively, various buckling load factors are obtained for stiffened laminated composite panel with trapezoidal type stiffeners and various longitudinal length to radius ratios, which are made from Carbon/Epoxy USN 125 prepreg and are simply-supported on four edges under uniaxial compression, and then for them, optimal design analyses are carried out by the nonlinear search optimizer, ADS.

• 한국산학기술학회논문지
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• 제19권1호
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• pp.714-721
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• 2018

본 논문은 강교량 거더, 교각, 선박이나 대형 저장 시설 등 주요 구조 부재에 활용되는 곡판 및 강관을 효과적으로 보강하는 방안에 관한 것이다. 최근 연구에서 압축을 받는 평판이 종방향 보강재의 단면회전강성에 의해 국부좌굴강도가 향상되는 특징을 정량적으로 분석하였고, 폐단면리브 단면회전강성과의 상관관계를 규명한 바 있다. 본 논문에서는 곡판에 대해 이와 같은 효과를 정량적으로 검토하고자 한다. 일축압축이 재하된 경우에 폐단면리브로 보강된 두께방향으로 곡률을 가지는 곡판의 좌굴거동을 살펴보기 위해 범용 구조해석 프로그램인 ABAQUS를 이용하여 3차원 유한요소해석 모델을 생성하였다. 이를 통해 좌굴거동에 대한 수치해석을 수행하였으며, 영향인자에 대한 변수해석적 연구를 수행하여 좌굴응력과 좌굴모드의 변동특성을 정량적으로 평가하였다. 폐단면리브 단면회전강성의 구속효과로 인한 좌굴강도 증가효과와 판의 곡률에 따른 좌굴강도 계수를 고려하여 좌굴강도를 추정하는 방법론을 이론적으로 제안하였다. 제안된 공식은 유한요소해석 결과와 비교하여 서로 유의미성이 검토되었다. 또한 평판에서와 마찬가지로 일축압축 상태에서 폐단면리브의 단면강성에의해 부여되는 양측단 회전강성의 증가로 인해 곡판의 국부좌굴강도가 이에 비례하여 증가하였고, 양측단에서 회전이 고정된 곡판의 좌굴강도에 수렴하는 경향을 확인하였다.

• 한국기계가공학회지
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• 제4권2호
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• pp.43-49
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• 2005

The purpose of a fatigue crack arrest design is to prevent a fatigue fracture of machine and structure resulted from unstable crack growth. In all cases of load transfer to second elements such as stringers, doublers or flanges, crack arrest is possible; arrest occurring when the fatigue crack reaches the second element. In the present work, a numerical analysis was carried out to estimate the effect of shape parameters on fatigue crack growth and arrest behavior of integrally stiffened panels. Based on these results, a set of fatigue crack arrest design chart is presented as "non-dimensional arrest load - thickness ratio" relationship.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.39-59
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• 2014

Nowadays aluminum stiffened plates are one of the major constituents of the marine structures, especially high-speed vessels. On one hand, these structures are subject to various forms of loading in the harsh sea environment, like hydrostatic lateral pressures and in-plane compression. On the other hand, fusion welding is often used to assemble those panels. The common marine aluminum alloys in the both 5,000 and 6,000 series, however, lose a remarkable portion of their load carrying capacity due to welding. This paper presents the results of sophisticated finite-element investigations considering both geometrical and mechanical imperfections. The tested models were those proposed by the ultimate strength committee of $15^{th}$ ISSC. The presented data illuminates the effects of welding on the strength of aluminum plates under above-mentioned load conditions.