• Journal of the Korea Computer Graphics Society
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• v.12 no.2
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• pp.39-44
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• 2006

컴퓨터 그래픽스 분야에서 변형체 애니메이션은 매우 중요한 기법으로 그 응용 범위가 매우 넓다. 본 논문에서는 큰 회전 변형에도 부피의 왜곡이 발생하지 않으며, 변형체의 어느 한 부위가 고정되어 있지 않고 자유롭게 움직일 수 있는 동적 탄성 변형을 실시간에 시뮬레이션 하는 기법을 제안한다. Choi와 Ko [3]가 제안한 모달 와핑 기법은 실시간에 부피의 왜곡이 없는 동적 탄성 변형을 생성할 수 있지만 탄성체의 어느 한 부위가 고정 되어 있어야 하며, Hauser 등 [9]이 제안한 임펄스 기반의 충돌 반응을 고려한 선형 모달 해석법은 안정적인 시뮬레이션 결과를 주지만 큰 변형에 있어서 부피 왜곡이 있다. 본 논문에서는 Choi와 Ko [3]가 제안한 모달 와핑 기법을 임펄스 기반의 충돌 반응을 포함하도록 확장하여 큰 회전 변형에도 부피의 왜곡을 방지하며 또한 자유롭게 움직이는 탄성체의 충돌 반응을 안정적으로 시뮬레이션 할 수 있게 한다.

• Journal of KSNVE
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• v.7 no.2
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• pp.331-345
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• 1997

A theoretical formulation for the analysis of free vibration of clamped-free cylindrical shells with plates attached at arbitrary axial position(s) was completed and it was programed to get the numerical results which yield natural frequencies and mode shape of the combined system of the plate and the shells. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis. The results shows good agreement with those of ANSYS and test results in frequencies and mode shapes. The method developed herein is likely to be used for the analysis of the free vibration of the clamped-free circular cylindrical shells with any kinds of lids such as hollow circular plates, conical shells, spherical shells, or semi-spherical shells.

• Journal of KSNVE
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• v.6 no.1
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• pp.97-106
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• 1996

This paper presents systematic study of the experimental application of a free-interfaced component mode synthesis method. In the free-interfaced component mode synthesis method, an error the to truncated higher modes and neglected ineria loadings on a component from the connected component is inherent. Also, it is difficult to directly use experimental modal data in a modal synthesis method which links experimental model to finite-element model because of many inconsistencies between experimentally obtained and analytically obtained modal vectors and missing degrees-of-freedom (DOFs) such as rotational DOFs. In order to solve these problems, three methods, the first one based on attaching auxiliary weights to the connection points, the second one utillizing the normalization of experimental modal vector, and the third one generating smoothed and expanded experimental mode shapes, are studied in this paper. Finally, the study is illustrated for a flat-plate structure by using simulated and measured experimental data.

• Journal of Navigation and Port Research
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• v.36 no.3
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• pp.163-168
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• 2012

Recently, people's desire for the waterfront space has been increasing, and more people want to spend their leisure time close to the water. This paper proposes a damage detection technique using the static strain for the floating structure. An existing damage index, in which the modal strain energy was utilized to identify possible location of damage, is expanded to apply the static strain. The new damage index is expressed in terms of the static strains of undamaged and damaged structures. After calculating damage index, the possible damage locations in the structure are determined by the pattern recognition technique. The accuracy and feasibility of the proposed method is demonstrated by using experimental strain data from a scale model of floating structure.