• Journal of the Korea Institute of Building Construction
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• v.5 no.4 s.18
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• pp.139-144
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• 2005

A ground anchor system is used as a load carrying element in soil work. The conventional systems with ground anthers bring about the anchorage loss of wedges when anchors are installed for the support of soil structures. Hence we developed the new type of anchor system using both the spacing apparatus and spring (length 60mm, diameter 6mm). In this system, we tan directly check the condition of wedges and PS strands and modify the problems with the slip and anchorage of wedges under construction. For demonstrating the superiority of this system, we carried out a series of the laboratory test. Consequently, we can obtain satisfactory result (18.99$\%$ reduction to the loss of conventional systems). Moreover, the replacement of wedges is easy and simple when retensioning of strands.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.410-415
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• 2002

A winding bend rig is designed to overcome the drawbacks of the conventional bend rig for measuring springback ratio of a strip or plate. Using the present bend rig, springback ratios are measured and they are compared with ones that obtained by using simple beam theory and tensile test. Theoretically, there should be no difference between the two values as far as the simple beam theory holds true for the bending test. But, within the scope of our tests, there is a difference of 5% between the two values since the specimen under bend test is subjected to a transverse shear force and friction force on the surface of the specimen.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.44-49
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• 1999

This paper is concerned with the theoretical and experimental study on the force conrtrol of a miniature robotic gripper. The gripper is an uniform flexible cantilever equipped with a distributed set of compact force sensor. As an actuator piezoelectric acturator, piezoelectric acturator is fixed with cupper plate at which the beam is clamped. The mathematical model of the assembled electro-mechaincal system is developed. The force sensor is described by a set of concentrated mass-spring system. The formulated equations of motion are applied to he study of a control problem where the gripper is commanded to grip an object The usefulness of the PID control technique is verified by experiment.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.147-154
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• 2003

Radial Dual Mass Flywheel(RDMF) is designed to reduce torsional vibration and noise occurring in automotive powertrain. In this paper, finite element method is used to evaluate stress level and critical area of the torsional spring box, a major part of RDNF system. In finite element analysis, both static and dynamic loadings are considered and it is found that the most critical spot is the welded zone of spring box. Also, fatigue test is performed and fractured surfaces are examined to find fatigue stress level by experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.836-839
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• 2006

This paper presented comparison of vibration characteristics of a 5-ton truck at the two kinds of rear axle suspension, a conventional leaf spring suspension and an air spring suspension. Vibration at the selected location in the freight compartment and the rear axle were measured while the vehicle was running on various kinds of road at the specified speed. At all kinds of the driving conditions used in the test the air spring suspension showed good performance of vibration attenuation, especailly at the frequency range of under 5 Hz.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.37-39
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• 2011

예선이 부선을 예인줄로 연결하여 운항할 시 예인줄에 걸리는 장력 및 형상을 예인줄을 다물체로 분할하여 모델링하였다. 이러한 예인줄 요소에 대한 횡동요를 제외한 5자유도 운동방정식을 구성하고, 각 요소들에 작용하는 힘을 정식화하여 연성 운동방정식을 도출하였다. 예인줄 요소들 간에는 예인줄의 재료 특성에 따른 강성을 가진 스프링과 감쇠장치로 연결하여 동력학적 조건을 부가하였고, 요소의 변형을 허용하는 형태로 운동학적 조건은 설정하지 않았다. 예인줄의 다물체 모델링의 검증을 위하여 단순 낙하, 직진, 사인파 형태로 지그재그로 움직이는 예선과 단순 항력체로 가정한 부선의 운동에 대한 시뮬레이션을 수행하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.214-218
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• 2016

Catenary maintains the tension of the catenary using automatic tensioning devices to meet performance require m ents exhibited by the house is generated in accordance with the new external temperature changes. Double spring type autom a tic tensioning device is permanent and does not require the usual maintenance, and a deterioration due to no recognizable ab normalities characteristic of the nature of the internal state has the disadvantage that can not be confirmed. The disassembled for automatic spring-tension capabilities ensure efficient operation and life expectancy of the adjustment device via a check by analyzing the changes in old age determine the remaining lifetime is expected to be available as a basis for maintenance in the future.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.63.1-63.1
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• 2012

한국천문연구원은 GMT (Giant Magellan Telescope)의 부경 중의 하나인 FSM (Fast Steering Mirror)의 시험모델을 개발 중이다. 구경 1.06m의 반사경을 가공하는 중인데, 뒷면 경량화 가공을 마쳤다. 다음 작업으로 비축 비구면의 앞면을 가공하기 위해 반사경의 지지셀을 제작 중이다. 또한 tip-tilt 제어를 위한 test-bed를 제작하여 스프링과 진공을 이용한 무게 상쇄실험을 마쳤다. 미러 셀을 제작하여 실제 상황과 비슷한 환경에서 시험하고자 한다. 또한 tip-tilt의 최종 성능시험을 위한 장치를 개발하고 있다. 이 발표에서는 FSM 시험모델의 개발 현황에 대해 논한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.418-421
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• 2001

Press brake is used as bending and forming sheet metal in vehicle and many kind of industry. This paper deals with development of NC press brake based on high precision positioning device and software, which can be operated on personal computer. In this system, positioning device is used for controlling bending angle and operated by the developed software, which is database from material property, width and thickness of material. This study will make distribution in development of computer aided press brake.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.620-623
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• 2000

The leaf spring is generally used effectively in load supporting because it has tension-diffused function in comparison with other springs. Nowadays the leaf spring is used widely in the suspensions of automobile and trains. The stiffness and the damping characteristics of the leaf spring being essential for the performance of vehicles, the exact evaluation is required. Various approximate formula are normally used for the leaf spring design. however, accuracy and trust are decreased because the contact and frictional characteristics between leaf plates are generally neglected. In this paper, nonlinear stiffness matrix of the leaf spring is solved by contact-element applying FEM for considering the contact and frictional characteristics between leaf plates. The results of proposed FE model are compared with test data.