• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.823-829
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• 2002

The composite frame system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however has also a lot of problems in practical design and construction process due to the material dissimilarities. Considering these circumstances, this research is aimed at the development of the composite structural system which enables the steel beams to be connected to the R/C columns with higher structural safety and economy. Basically the proposed connection system is composed of four split tees, structural angles reinforced by stiffener, high strength steel rods, connecting plates and shear plates. The structural tests have been carried out to verify the moment transfer mechanism from beam flange to steel rods or connecting plates through the angle reinforced by siffener. The four prototype specimens have been tested until the flange of beam reached the plastic states. From the tests, no distinct material dissimilarities between concrete and steel have been detected and the stress transfer through wide flange beam - structural angle - high strength steel rod or connecting plate is very favorable.

• 기계와재료
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• v.23 no.3
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• pp.164-172
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• 2011

기계-유압식 무단변속기인 DMT는 농촌의 고령화의 추세에 맞물려 중 대형 트랙터의 핵심기술로 부각되고 있다. DMT는 기계동력과 유압동력인 두 개의 전달 구조를 조합하고 서로의 단점을 보완함으로써 기동력이 우수하고, 변속충격이 거의 없고, 전달효율이 향상되고 있다. 트랙터용 DMT는 유압동력을 전달하는 HST, 기계동력을 분배 뽀는 합성하는 유성기어 장치, 전진과 후진을 선택하는 전 후진 클러치, 출력축을 정지하는 브레이크 등으로 구성되어 있다. 본 연구에서는 DMT의 핵심기술인 HST와 유성기어장치에 대한 내부구조 및 동력전달을 해석하고 시제품의 실험결과를 제시하여 국내에서 진행되고 있는 DMT의 연구현황을 소개하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.145-151
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• 1998

This paper addresses the results of an experimental and analytical research of cylindrical coil spring subjected to dynamic behavior. Transfer functions are presented for both deflection and transmitted force as the output with force as the input. Steady state sinusoidal magnitude ratio and transmittance are plotted along with experimental data. It is shown that dynamic characteristic of cylindrical coil spring must be used to enhance the reability of vibration system dynamic behavior analysis in actuating over some frequency.

• Ceramist
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• v.7 no.3
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• pp.34-37
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• 2004

최근 미세가공 기술의 발달로 미세계에서의 전달현상에 대한 관심이 증대되고 있다. 미세계에서는 몇 가지 물리적 효과들이 중요하게 된다. 미세 흐름에서는 관성력과 점성력의 비인 Reynolds 수가 아주 작게 되고 계의 길이 차원이 작아짐에 따라 표면력(suface force)의 효과가 중요하게 되면서 보통은 무시되었던 몇몇 효과들이 중요하게 된다. 그 중의 하나가 혼합이다. (중략)

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.10-21
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• 2014

The joint of prefabricated steel grid composite deck is composed of concrete shear key and high-tension bolts. The flexural and shear strength of the joint were experimentally evaluated only by the bending and push-out test of the joint element. In this study the lateral load transfer behavior of the joint in deck structure system is experimentally evaluated. Several decks connected by the joint are prefabricated and loaded centrically and eccentrically. In the case of centrically loaded specimens, the analysis results show that for the same loading step the rotation angle of the joint with 4 high-tension bolts is larger than the case of the joint with 9 high-tension bolts. Consequently, flexural stiffness of deck and lateral load transfer decrease in the case of specimen with 4 high-tension bolts. But, in the case of eccentrically loaded specimens, it is found that there are no significant differences in the load transfer behavior. The further analysis results about the structural behavior of the joint show that lateral load transfer can be restricted by the load bearing capacity of the joint as well as punching shear strength of the slab. Furthermore, considering that high-tension bolts in the joint didn't reach to the yielding condition until the punching shear failure, increase in the number of high-tension bolts from 4 to 9 has a greater effect on the flexural stiffness of the joint and deck system than the strength of them.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.81-90
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• 2013

The purpose of this study is to evaluate the horizontal shear strength on the interface between PC and cast-in-place concrete for PC composite beams. Six specimens were tested to examine the structural performance of the horizontal interface with different surface condition and stirrup detailing. Except for SF-291B specimen failed in flexural compression, strengths and deformation capacities of five specimens were determined by horizontal shear failure. Horizontal shear strengths by composite horizontal shear or shear friction in current codes could be used to predict the horizontal shear capacity of the interface for specimens. Also detailing for stirrup by PCI design provision could be used to accomplish the composite action in the interface.

• Journal of Korean Association for Spatial Structures
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• v.9 no.2
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• pp.45-52
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• 2009

This paper experimentally evaluates the strength characteristics of precast column-R.C. foundation anchor joint subjected to the cyclic horizontal load. The study presents differences in accurate stress transfer path and destruction mechanism between the concrete structural body applying the precast column-R.C. foundation anchor joint and the concrete structural body applying the steel joint. the result from width load experiment on reinforcing steel under the cyclic horizontal load provides the necessary minimum insertion length to construct the precast column-R.C. foundation anchor joint. This study also presents the accurate stress transfer path and destruction mechanism on the anchor joint th meet the customer's requirements, comparing stress transfer path and destruction mechanism provided by the experiment and those provided by the product manual. Eventually, this study presents all the necessary fundamental data to provide the construction design with accurate number of reinforcing steel, diameter of the steel, fixation length of the steel, etc. to build the optimum precast concrete column.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.33-43
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• 2006

Driving tests using model plastic piles with different hammer cushion materials were performed in order to evaluate the efficiency of energy transfer ratio from the hammer, degree of vibration of the surrounding ground and noise due to impacting. A small pile driving analyzer (PDA) was composed using straingages and Hopkinson bar which is measuring force signal and pile-head velocity. The hammer cushion (cap block) materials used for the model driving tests were commercial Micarta, plywood, polyurethane, rubber (SBR) and silicone rubber. The highest energy transfer ratio was obtained from Micarta in the same soil and driving conditions. Micarta was followed by polyurethane, plywood, rubber and silicone in descending order. The more efficient energy transfdr ratio of the hammer cushion materials became, the bigger average noisy (sound) level was found. In addition, Micarta and polyurethane provided bigger bearing capacities than other materials compared in the same soil and driving conditions in which the static loading tests were performed at the end of driving.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.95-96
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• 2009

In this paper, the transfer lengths in pretensioned prestressed Ultra High Performance Concrete members are verified to collect the basis data of UHPC increased in practical uses recently. The cover sizes and pretension forces were the main parameters of UHPC.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.792-796
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• 2013

A practical process to optimize engine mounts on construction equipment is presented in this research. Transmitted force from the engine is estimated by using stiffness of the mount rubber which varies with frequency, amplitude and pre-load, and by the engine excitation force that comes from piston mass and gas pressure and so on. The transmitted force is measured through TPA(Transfer Path Analysis) and is then compared with the estimated force. The optimum mount position and stiffness are solved using MATLAB. The result shows the improvement on engine mount vibration.