• Composites Research
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• 제34권6호
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• pp.350-356
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• 2021

활주 선형의 선박은 직선으로 운항하거나 선회할 때, 그 속도에 따라 위치와 트림이 변화하며, 선체에 큰 저항이 발생한다. 본 논문에서는 탄소복합소재를 선체에 적용하여 선체무게와 내구성이 향상된 레저보트의 전산유체역학을 통해 선형에 대한 저항을 추정하였다. 18ft급 레저보트의 선수부와 선미부의 저항 성능을 확인하고 선형 전체의 유동장을 추정하였으며, 수치해석을 통해 각 트림의 저항을 비교하여 선형에 대한 안정성을 확인하였다. 또한, 선체에 걸리는 힘이 크지 않아 설계된 선형이 충분히 견딜 수 있을 것을 확인하였고, 파도의 파장과 배의 길이를 관성력에 대한 중력의 비로 계산하여 롤링이 얼마의 힘으로 발생하는지 확인하여 보트의 안정성을 분석하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.548-551
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• 1999

The cure characteristics of metal particle filled DGEBA/MDA/SN/ zeolite epoxy resin composite system for EMI shielding were investigated by dynamic DSC run method and FT-lR spectroscopy. As the heating rate increased, the peak temperature on dynamic DSC curve increased because of the rapid cure reaction. From the straight line of the Kissinger plot, the curing reaction activation energy and pre-exponential factor could be obtained. As the post-curing time at 15$0^{\circ}C$ increased, the glass increased the glass transition temperature or the thermal stability increased. When the post curing time is too long, the system filled with metallic Al particle can be thermally oxidized by the catalytic reaction of metal filler and the thermal stability of the composite for the EMI shielding application may be decreased.

• 한국터널지하공간학회 논문집
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• 제19권3호
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• pp.421-435
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• 2017

최근 국내 지상 구조물의 포화 및 파이프 라인 시설 과밀화 현상과 난개발로 인해 지상 구조물의 대안으로 지하 구조물에 대한 개발이 지속적으로 요구되고 있다. 도심지 인프라 구축을 위한 NATM 터널 공사에 발생하는 진동 및 소음 문제를 예방하기 위해 기계식 터널 공법인 쉴드 TBM 공법의 기계화 터널 시공이 증가하는 추세이다. 따라서 본 연구에서는 기계화 터널의 직선 시공과 급곡선 시공 시 쉴드 TBM의 구조적 안정성을 위한 쉴드 TBM 추력에 대한 중절잭, 쉴드 잭, 스킨 플레이트의 구조적 안정성 기술에 대해 연구하였다. 시공 사례 및 쉴드 TBM의 작동원리를 이론적 접근 방법으로 검토, 분석한 결과, 쉴드 TBM의 직선 및 급곡선 시공시 주요 인자에 의해 커터헤드의 회전력, 중절잭, 쉴드 잭에 대한 추력 및 커터헤드의 여굴량이 중요한 것으로 나타났다. 또한 굴진 내부 작업자의 안전 및 장비의 원활한 작동을 위해 스킨 플레이트 구조의 안정성 확보는 매우 중요 사안이므로 이번 연구를 통해 장비의 일반적인 구조 및 구성을 검토하여 직선 및 급곡선 시공 시 스킨 플레이트 구조에 미치는 주요 인자 및 구조 안정성을 실험적인 시뮬레이션 수치해석을 통해 검토하였다. 이에 직선 및 급곡선 시공 시 작용 되는 가상의 토질을 선정하여 중절잭의 하중을 비교 검토 하여 스킨 플레이트의 구조 안정성을 평가하고 형상을 최적화 하였다. 현재 국내 시공 중인 쉴드 TBM 타입의 구조 및 작동 방식이 매우 유사하므로, 추후 국산화 기술 개발 및 신규 장비 개발과 쉴드 TBM의 취약부 및 안정성을 검토하는데 기여 할 것으로 기대된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1161-1170
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• 2009

The Roads in Gangwon Province generally was made on purpose to use the military road. In case of these roads, tremendous dangerous cut slopes do exist and its road linear shape was badly designed. In order to make up for this situation, the government has continuously established the new road or performed the public works such as the straight line of the curved road. Soksil 2 cut slope was made through the road improvement work. This has small surface failures and collapses. In spite of dry season, this slope are leaking lots of groundwater at the unbelievable point. So as to get curious phenomenon right, we performed a detailed field investigation, the geomorphological analysis, the stability analysis considering field characteristic and ultimately proposed the countermeasure to make sure stability of Sokil 2 cut slope.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.1-11
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• 1998

The 4WS system is usually developed to improve the maneuverability at low speed and the straight line stability at high speed, but it is found to have the severe understeer characteristics at high speed. Therefore a 4WS vehicle requires to turn the steering wheel much more than a 2WS vehicle at high speeds even a driver goes through the same curved road. In this study, to enhance the cornering performance of the 4WS vehicle at high speed, a DYC 4WS system is proposed based on the nonlinear 4WS system and direct yaw moment control system. Especially the proposed DYC 4WS system is able to realize a zero side slip angle for vehicles and a cornering performance similar to the 2WS vehicle at high speed.

• 한국안전학회지
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• 제12권3호
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• pp.147-154
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• 1997

The main purpose of this study is to investigate the failure surface in a soil mass by a excavation of the model ground. The failure mechanism of an earth structure is usually determined from field failure observations or from laboratory model tests at failure. To study the failure surface for the excavated slope, laboratory model tests were performed by changing the angle of the excavated slope and the ground condition. Results of the laboratory model tests were compared with those obtained with theoretical solutions using limit equilibrium analysis method. The results of model tests show that, there is a failure to create a straight line in the low angle of excavated surface and a create a circle as the angle increases. As the angle of excavated surface is increasing, the angle of the failure surface increases too. In the angle of the failure surface, the submerged ground is less than the dry ground at $3.2^{\circ}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.415-417
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• 2005

This paper proposes tracking control method using pseudo-backstepping control for wheeled mobile robots with nonholonomic constraints. First, the pseudo commands for forward linear velocity and angular velocity are chosen based on the kinematics. Then, the actual torque control inputs are designed to make the actual forward linear velocity and angular velocity follow the pseudo commands. Both semi-global practical posture(position and heading direction angle) stabilization and trajectory tracking are achieved for reference trajectories such as straight line and sinusoidal curve. The stability and performance analysed and numerical simulations are performed to confirm the effectiveness of the proposed scheme.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.186-194
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• 2003

This paper proposes a combined controller frame of the adaptive robust control(ARC) and the sliding mode control(SMC) for the trajectory tracking control of the excavator to preserve the advantages of the both methods while overcoming their drawbacks, namely, asymptotic stability of adaptive system fir parametric uncertainties and guaranteed transient performance of sliding mode control for both parametric uncertainties and external disturbance. The suggested control technique is applied for the tracking of a straight-line motion of end-effector of manipulators, and through computer simulations, its trajectory tracking performances and the robustness to payload variation and uncertainties are illustrated.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.22-29
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• 2004

This paper studies the coordinated trajectory control of an excavator as a kind of robotic manipulators driven by hydraulic actuators. Hydraulic robot system has many non-linearity in dynamics and kinematics, and strong coupling among joints(or hydraulic cylinders). This paper proposes a combined controller frame of the adaptive robust control(ARC) and the sliding mode control(SMC) for the trajectory tracking control of the excavator to preserve the advantages of the both methods while overcoming their drawbacks, namely, asymptotic stability of adaptive system for parametric uncertainties and guaranteed transient performance of sliding mode control for both parametric uncertainties and external disturbance. The suggested control technique is applied for the tracking of a straight-line motion of end-effector of manipulators, and through computer simulations, its trajectory tracking performances and the robustness to payload variation and uncertainties are illustrated.

• 전기학회논문지
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• 제57권1호
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• pp.92-97
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• 2008

This is a research to apply 1310nm single-mode optical fiber to a temperature sensor. The existing study of optical fiber sensor is complicated because it was made with various equipment. To vary scattering, the variation of optical frequency is measured by using Bragg(lattice) or pulse generator and also bulk system is created by YAG laser but there were some difficulties creating experimental environment and it was a problem that the stability of measured data was low. The temperature sensor system using the suggested sBs(stimulated Brillouin scattering:sBs) from this research is much more simplified straight-line system. To improve the trust and accuracy of noises from optical frequency and unclear results, it was analysed by using Neuro-Fuzzy algorithm. we tried to get more correct data than existing system. sBs measure that optical frequency changed due to the variation of temperature. The analyzed change rate of outcome by Fuzzy theory is 1.1 MHz.