• 수산해양기술연구
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• 제28권1호
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• pp.79-92
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• 1992

This is analyzed using the finite element method which is appling excellent isoparametric curve element in the aspect of large usages of dynamic responses in which is regarding geometric and material nonlinear of a large scale shell structure of an airplane, a submarine, a ship, and an ocean structure. The solution of dynamic equations is got by direct integration method using time-stepping procedure and regarding Central Difference Method of the both solutions. But because formal matrix factorization is not necessary in each time step and it does not take less time to compute relatively, this method must be regarded very few time steps on the condition. Axisymmatric shell problems are inspected using 8 node Isoparametric element in this paper. Partial axisymmatric spherical shell is used as a model to analyze axisymmatric nonlinear dynamic behavior regarding. Total Lagrangian formulation in geometric nonlinear behavior and elastio-viscoplastic in material nonlinear behavior.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.196-201
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• 2001

Very Large Floating Structures have been planned for effective utilization of ocean space in recent years. The VLFS usually has a control tower to guide airplane securely. This paper present an effective method for calculating the wave induced hydroelastic responses of VLFS considering the effect of control tower-shapes. The source and dipole distribution method is used to calculate the hydrodynamic loads and equation of motion is derived by considering the static and dynamic coupling effects from different segments of the plate. The rigidity matrix for VLFS is formulated by finite element method using a plate theory. The calculated results for VLFS with a control tower are compared with those for VLFS without a control tower.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.7-14
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• 2001

For the development of the practical methods of structrual analysis of typical VLFS. Orthortropic plate theory and a grillage beam theory and modeling techniques are studied and relevant numerical analysis are carried out. For the design of pontoon type VLFS, an efficient and reliable structural analysis techniques must be established, and as corresponding methods, two approaches mentioned above were studied in view point of their applicability and efficience. For that purpose, structural idealization is performed to make overall structural analysis first, and the structural behaviors of the model in the airplane landing simulation are evaluated. Through this study it is found that the structural idealization using orthotropic plate and grillage modeling are porved to be adequate and the numerical analysis results for real VLFS yields acceptable deformations in the corresponding simulations.

• 한국항공운항학회지
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• 제13권1호
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• pp.9-19
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• 2005

Airplane fuel takes large portion of airline operation cost and recently it has been grown up to about 25% of operating cost. So airlines are making efforts to reduce fuel consumption continuously and also aircraft manufacturers are making efforts to develop less fuel-consuming engines but it takes great expenses and times to develop such engines. In this study, fuel requirements of FAR and JAR, especially contingency fuel requirements, are compared and the effectiveness of each method is analyzed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.510-515
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• 1998

Most of large structures such as ship, airplane, and so on have internal structure home noise sources. The operation of the machineries results in vibration and noise of the structure. Particularly, the vibration of the machineries is transmitted to the far place from the sources and emits noise into the water or outdoor as well as the inner space of the structure. In the case of warships this emission into the water induces noise to reduce the performance of its underwater acoustic equipment. Therefore the structure home noise levels of the installed machineries are strictly limited. This paper shows examples of structure home noise reduction from machineries including pumps.

• 대한인간공학회지
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• 제15권2호
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• pp.99-111
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• 1996

In today's highly automated aircraft, the role of the pilot has changed from an airplane controller to a system manager. As a system manager in a cockpit, today's pilot is in charge of a management-level activity called cockpit task management( CTM). According to earlier studies, pilot errors in performing CTM activities were significant factors in a large number of aircraft accidents and incidents. The primary objective of this research was to reduce CTM-related pilot errors. A prototype pilot- vehicle interface called the cockpit task management system (CTMS) was developed and its effectiveness in improving CTM performance was evaluated. After the CTMS was implemented, it was integrated into a PC-based flight simulator to perform an experiment to evaluate its effectiveness. Eight volunteer subjects were used to collect performance data. The results of the experiment indicated that a statistically significant improvement was observed when the subjects flew with the assistance of the CTMS.

• 연구논문집
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• 통권33호
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• pp.183-190
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• 2003

Today, We have used many electronic equipment such as computer, TV, cellular phone and so on. These equipment radiate a large amount of EMI(Electromagnetic interference) which is occurred trouble of airplane, medical equipment, communicate equipment, and especially, human health. So, Ni mesh fabrication for EMI shielding by continuous electroforming process was investigated. Continuous electroforming apparatus was made by means of rotating cathode drum. And We investigated the characteristics of two types of Ni electroforming solution. One was made by laboratory and the other was produced by M cooperation. The grain size increased with increasing current density and bath temperature, and decreasing rotating speed of cathode drum. EDX results indicate that the Ni mesh electroformed by the KIMM solution is composed of pure Ni. But the Ni mesh electroformed by the M cooperation solution has Ni and S element. The incorporation of S element in the Ni mesh has a profoundly effect on mechanical properties such as hardness, internal stress and so on.

• 한국해양공학회지
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• 제16권2호
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• pp.32-37
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• 2002

Very Large Floating Structures have been planned for effective utilization of ocean space in recent years. The nonerctangular VLFS usually has a control tower to guide airplane securely. This paper presents an effective method for calculating the wave induced hydroelastic responses of VLFS considering the effect of control tower-shapes. The source and dipole distribution method is used to calculate the plate. The rigidity matrix for VLFS is formulated by finite element method using a plate theory. The calculated results for nonerctangular VLFS with a control tower are compared with those for VLFS without a control tower.

• 한국항공우주학회지
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• 제47권4호
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• pp.266-273
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• 2019

다수의 소형 정찰용 무인항공기를 이용하여 탐색 및 정찰 임무를 수행하는데 있어서 무인항공기의 운용 대수, 비행고도 등 운용 조건에 따라 임무 수행의 효율성과 효과성은 크게 변경될 수 있다. 하지만 어떤 운용조건이 가장 합리적인지 판단하기는 쉽지 않다. 따라서 본 연구에서는 자율비행에 따라 충돌을 회피하면서 표적을 탐지 및 판별할 수 있는 무인항공기 비행 시뮬레이션을 개발하여 다수의 무인항공기 운용 시 보다 효과적이고 효율적인 운용조건을 도출할 수 있는 방안을 제시하였다.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.130-137
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• 2010

Due to test facility and specialty, it is physically difficult to conduct the modal tests of large-sized structures such as truck, bus and airplane. So, in case of a large-sized truck, the mode analysis on a full vehicle model comprised of reliable cabin, frame, and deck has been generally performed. However, the reliability of overall vibrational characteristics of the analytic model has not been fairly guaranteed by the testified models of each subsystem owing to the existence of cab suspension and the nonlinear mounting between a chassis frame and a special deck system. In this paper, a method to find out the modal characteristics of a large-sized military truck is presented. New modal test equipment is developed to set the boundary conditions of three military truck variants as close as a free-free condition. And the mode analysis method using coupled structure and dynamic models is established to consider the above-mentioned dynamic non-linearities of the vehicle itself. The usefulness of the suggested method is verified by comparing with the modal test results. Finally, the modal parameters of the final variant are extracted using the proved analytic method.