• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.

• 한국해안해양공학회지
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• 제15권4호
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• pp.232-241
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• 2003

3차원 선형포텐셜 이론아래에서 해저면 바닥에 고정된 N개의 투과성 원기둥과 입사파의 상호작용 문제를 살펴보았다. 유체영역을 때의 외부영역과 N개의 내부영역으로 나누고, 각 유체영역에서의 회절포텐셜을 고유함수전개법에 의해 표현하였다(Williams and Li, 2000). 투과성 구조물은 파력과 처올림 파형을 크게 줄일 수 있다는 사실을 해석결과는 보여주고 있다. 개발된 해석모델을 검증하기 위하여 일렬로 배열한 투과성 원기둥들을 가지고 조파수조(30m $\times$ 7m $\times$ 1.5m)에서 체계적인 모형실험을 수행하였다. 해석결과와 모형실험결과는 정성적으로 잘 일치하고 있음을 확인하였다. 투과성 원기둥을 일렬로 배열하여 만든 방파제는 해수교환뿐 아니라 우수한 소파성능을 가지고 있어 미래의 해수교환방파제로써 무한한 잠재력이 있다고 판단된다.

• Structural Engineering and Mechanics
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• 제13권6호
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• pp.615-638
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• 2002

This paper presents a method of seismic analysis for a cylindrical liquid storage structure considering the effects of the interior fluid and exterior soil medium in the frequency domain. The horizontal and rocking motions of the structure are included in this study. The fluid motion is expressed in terms of analytical velocity potential functions, which can be obtained by solving the boundary value problem including the deformed configuration of the structure as well as the sloshing behavior of the fluid. The effect of the fluid is included in the equation of motion as the impulsive added mass and the frequency-dependent convective added mass along the nodes on the wetted boundary of the structure. The structure and the near-field soil medium are represented using the axisymmetric finite elements, while the far-field soil is modeled using dynamic infinite elements. The present method can be applied to the structure embedded in ground as well as on ground, since it models both the soil medium and the structure directly. For the purpose of verification, earthquake response analyses are performed on several cases of liquid tanks on a rigid ground and on a homogeneous elastic half-space. Comparison of the present results with those by other methods shows good agreement. Finally, an application example of a reinforced concrete tank on a horizontally layered soil with a rigid bedrock is presented to demonstrate the importance of the soil-structure interaction effects in the seismic analysis for large liquid storage tanks.

• 복식
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• 제66권1호
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• pp.28-41
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• 2016

This paper is aimed at intensively examining the scope of legal protection for fashion designs under the Design Protection Act of Korea. For this purpose, this looked into how the Act defines the concept of design, its requirements, and the prerequisites for acquiring design rights. The study also reviewed statutory interpretations over the judgment of the identity and similarity of designs. For more practical and substantial discussions, this research utilized cases and precedents, which had relevant legal principles. This study also figured out how both the requirements for a design definition - such as merchantability, configuration, visibility, and aesthetics - and the prerequisites for acquiring design rights - like industrial applicability, novelty, and creativity - are interpreted and utilized in actual circumstances. The authors expressed their opinions regarding the criteria of judging the identity and similarity of designs, based on a study of previous cases. Previous rulings show that aesthetics of the exterior design is used as the criteria for determining whether a design is same or similar. So, two designs, which have different specific details, are deemed same or similar, if both designs show similarity in the dominant elements. This is because both designs will produce similar aesthetic qualities. However, if the dominant elements of a design are part of the public domain, and the specific details characterize the design, the latter has to be evaluated in the process. This paper examined scope of legal protection for fashion designs using relevant precedents. The study may serve as academic materials that lead to the establishment of rightful ownership in creative activities.

• 한국군사과학기술학회지
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• 제26권1호
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• pp.1-9
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• 2023

The skin structure of sensor pod mounted on the exterior of aircraft can be exposed to the acoustic dynamic load and static load such as aerodynamic pressure and inertial load during flight. Fatigue life prediction of structural model under acoustic load should be performed and also differential stiffness of model modified by static load should be considered. The acoustic noise test spectrum of MIL-STD-810G was applied to the structural model and the stress response power spectral density (PSD) was calculated. The frequency response analysis was performed with or without prestress induced by inplane static load, and the response spectrum was compared. Time series data was generated using the calculated PSD, and the time and frequency domain fatigue life were predicted and compared. The variation of stress response spectrum due to static load and predicted fatigue life according to the different structural model considering mean stress were examined and decreasing fatigue life was observed in the model with prestress of compressive static load.