• 한국생산제조학회지
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• 제25권4호
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• pp.245-252
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• 2016

Girth gears are applied in the mining, cement, and mineral processing industries and used in various types of horizontal mills, rotary dryers and kilns, and other heavy-gear ring applications. The large ring gears are normally fitted outside mills or kilns to provide the primary rotational drive. Recently, an external pinwheel gear set (e-PGS) was introduced to overcome manufacturing problems associated with girth gears. e-PGS is also suitable for low-speed, heavy-duty mechanical transmission and dusty and poor-lubrication conditions. This paper first presents a new profile modification of root relief for the e-PGS cam pinion. We then investigate load-stress factors to estimate the surface fatigue life by varying the shape design parameters. The results show that the contact fatigue life of an e-PGS can be extended significantly by increasing the profile shift coefficient. However, support bearing life of the pinwheel depends more on the contact force distribution than the profile shift coefficient.

• 한국생산제조학회지
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• 제21권1호
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• pp.130-136
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• 2012

Dynamic as well as static and geometric design parameters such as inertia, tooth profile, backlash and clearance can be directly considered via multi-body dynamic analysis along with contact analysis. However, it is time consuming to use finite elements for the consideration of the tooth flexibility in the multi-body dynamic analysis of gears. A computationally efficient procedure, so called, Gear Stiffness Module, is suggested to resolve this calculation time issue. The characteristics of gear tooth compliance are discussed and rotational stiffness element concept for the Gear Stiffness Module is presented. Transmission error analyses for a spur gear system are carried out to validate the reliability and efficiency of the module. Compared with the finite element model, the Gear Stiffness Module yields considerably similar results and takes only 3% of calculation time.

• 한국자동차공학회논문집
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• 제24권1호
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• pp.10-15
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• 2016

This research was conducted structural analysis in order to analyze the impact of the gear in Urea pump when the water is frozen. Subject of study, gear was designed nine models, this gear is a spur gear, located in pump. Contact conditions and rotation conditions were set the gear's condition of restriction. Given 136 MPa pressure to external gear by water was set to the applied stress. The performing result of structural analysis, maximum stress and strain are appeared between two gears. At the same diameter, strain and stress are decreased gradually thicker. Because of the little part in crevice between gears, this parts of gears could be obtained conclusion to be generated maximum stress and strain.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1275-1284
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• 2018

The coaxial magnetic gear with the flux concentrating structure is known that it has the torque performance advantage over the coaxial magnetic gear having surface mounted permanent magnet, thanks to the flux focusing effect. But, if the solid cores are used in the modulating pieces and rotor cores to consider the mechanical reliability and cost reduction, the operating torque of the flux concentrating coaxial magnetic gear can be significantly diminished because the iron losses at the solid cores affect the actual transmitted torque. Furthermore, the modulating pieces and rotor cores have different characteristics of the iron losses from one another, because the space harmonic components of the magnetic flux density, which cause the iron losses, are different. Thus, in this paper, we focused on the analysis of the characteristics of the space harmonic components of the magnetic flux density and resultant eddy current losses in the surface mounted PM and flux concentrating coaxial magnetic gears, when these coaxial magnetic gears have the solid cores at the modulating pieces and rotor cores. The characteristics of pull-out torque (static torque), operating torque (dynamic torque), and efficiency are also researched, and compared by the 3D finite element analysis (FEA) and experiment.

• 수산해양교육연구
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• 제12권1호
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• pp.98-121
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• 2000

The Korean fishery encountered a difficulty situation, due to the new regime of the Exclusive Economic Zone (EEZ) and the decreasing fisheries resources in Korean waters. In addition, the coastal areas are deteriorated by industrial wastes, sewage, farming wastes and pollution from aquaculture. In this situation, it is necessary to study the TAC (total allowable catch) - based management system, the development of fishing gears and appropriate fishing methods for stock conservation, and the automation system of fishing gears for improving the efficiency of fisheries. The objective of this study is to look for an appropriate system in marine production and resource management under the new UNCLOS (United National Convention for the Law of the Sea) regime for subjects in fishing gears and methods, production system, and information, and fisheries resources management. The results of this study could be used as scientific information to maintain and develop the Korean fisheries and to establish fisheries policy for the management of fisheries resources in Korean waters.

• 한국기계가공학회지
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• 제19권12호
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• pp.1-7
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• 2020

An experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears was performed using a Zwick fatigue tester. The gear material was manufactured using vertical continuous casting, resulting in the radius of the graphite grains being smaller. The stress-number of cycles curve (S-N curve) for the bending fatigue strength of the ADI spur gears thus manufactured, without any specific surface treatments, was obtained using post-processing software. It was observed that when the reliability was 50%, the allowable root stress was 610 MPa. was calculated using an analytical method as well as the finite element method, and the difference between the values calculated using the two methods is only 7%. This study provides a reliable basis to rate the reliability design of small gearboxes in automation in the future.

• 생태와환경
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• 제43권1호
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• pp.103-116
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• 2010

본 연구는 현재 국내 호수에서 사용되는 어구들(Sampling gears) 중 어류를 이용한 호수생태계의 건강성 평가에 적용할 수 있는 어구를 선정하기 위하여 각 어구별 채집 효율성을 분석하였다. 이를 위하여 진양호를 대상으로 2008년 11월과 2009년 6월 2회에 걸쳐서 어류조사를 실시하였다. 조사에 사용된 어구는 외통발(FN), 자망(GN), 삼중자망(TN), 투망(CN), 통발(MT), 족대(KN) 등 6개의 어구를 사용하였다. 진양호에서 채집된 총 어류는 1차 조사에서 20종의 4,149개체로 나타났으며, 2차 조사에서 27종의 3,364개체로 나타나 동절기(11월)인 1차 조사에 비하여 하절기(6월)에서 더 많은 종이 출현한 것으로 나타나 1, 2차 조사 결과, 총 어류는 29종의 7,513개체가 채집되었다. 어구별로 채집된 어종을 분석한 결과, 투망(CN)이 28종 3,567개체가 채집되었으며, 정치망(FN)이 15종 3,108개체, 삼중자망(TN)이 14종 577개체, 자망(GN)이 7종 107개체, 통발(MT)이 6종 59개체, 족대(KN)가 5종 95개체가 채집되어 투망이 총 및 개체수에서 가장 많이 채집된 것으로 나타났다. 어류채집도구별 다변량분산분석(MANOVA) 결과, 각 어구마다 채집되는 종수에 차이가 있는 것으로 나타났으며, 이중 CN을 이용한 다른 채집도구들에 비해서 가장 효율적인 것으로 분석되었다. 반면, MT과 KN이 어류채집 시 가장 낮은 효율성을 보이는 것으로 나타났다. 또한 유사도 분석에서도 CN이 전체 채집된 어류 자료와 95% 정도의 유사도를 보였으며, MT, GN, TN, KN으로 채집된 어류는 유연관계가 적은 것으로 나타났다. 본 연구는 호수생태계에서 어류조사도구별 효율성에 대한 예비연구로서 검증을 위해 향후 여러 호수에 대한 더 많은 연구가 뒷받침되어야 할 것으로 사료된다.

• 한국전산구조공학회논문집
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• 제30권2호
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• pp.169-177
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• 2017

본 논문에서는 기어 전달오차의 EEMD 적용을 통한 기어 이빨의 박리결함과 균열결함의 분류법을 소개한다. 두 가지 결함을 적용한 기어의 유한요소모델을 바탕으로 전달오차를 획득하고 전달오차에서 나타나는 두 가지 결함의 특징과 정상상태의 전달오차와의 차이를 나타내는 RTE에서 나타나는 두 가지 결함의 특징을 확인했으며 유한요소해석 결과를 이용한 시뮬레이션 신호를 구성하여 신호처리를 통한 RTE 획득과정을 구성하였다. 시뮬레이션 신호로부터 얻은 RTE의 EEMD 적용을 통하여 박리과 균열의 신호가 각기 다른 IMF에서 비중이 크다는 것을 확인하였고, 이를 실험을 통해 검증하고자 하였다. 한 쌍의 기어와 서보모터, 파우더브레이크 그리고 기어의 회전량을 측정하기 위한 엔코더로 구성되어있는 테스트베드를 꾸려 전달오차를 획득하였다. 두 개의 기어를 이용하여 정상, 박리, 균열 세가지 상황에 대한 전달오차를 획득하여 시뮬레이션과 같은 과정을 거쳐 결함이 신호로 구분되는 것을 확인했다. 이를 정량화 하기위해 파고율을 각 IMF에 적용하였고 첫 번째 IMF와 세 번째 IMF의 파고율을 특징 신호로 선정하였다. 실험을 통해 확보된 데이터를 이용하여 Bayes decision 이론을 이용하여 분류 방법을 제시하였다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2006년도 수산관련학회 공동학술대회 발표요지집
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• pp.578-579
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• 2006

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.61-62
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• 2010