• Tribology and Lubricants
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• 제33권4호
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• pp.134-140
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• 2017

With the increase in adoption of tilting pad journal bearings (TPJBs), various failure mechanisms related to TPJBs have been reported, of which pad wear is a frequently reported one. Pad wear causes change in geometry of the bearing, which can sometimes result in the failure of the entire system. The objective of this research is to investigate the influence of pad wear on the pad temperature, which is one of the widely used condition monitoring methods for TPJBs. For the theoretical investigation, thermohydrodynamic (THD) analysis was conducted by solving the generalized Reynolds equation and the 3D energy equation. The results of the analysis show that the temperature of the loaded pad increases while that of the unloaded pad decreases, when there is wear on the loaded pads. In addition, the minimum film thickness decreases with an increase in the wear depth. A validation test was conducted with a test rig, which mimics the axial turbine when a test rotor is supported by two TPJBs. The test bearing consists of five pads with a diameter of 60 mm, and a resistance temperature detector (RTD) is installed in the pad for temperature monitoring. The test was performed by replacing the two loaded pads with the worn pad. The test result for the TPJB with wear depth of $30{\mu}m$ show that the temperatures of the loaded pads are $8^{\circ}C$ higher and that of the unloaded pad is $2.5^{\circ}C$ lower than that of the normal TPJB. In addition, the predicted pad temperature shows good agreement with the measured pad temperatures.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.399-404
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• 1999

This study were performed to find the cooling effect and to provide design data during summer season for the Pad& Fan system of greenhouse . The temperature variation along the greenhouse width were analyzed. Also, the effect of the pad location and fan capacity on the cooling of the greenhouse were analyzed. While Pad &Fan systems were operating the temperatures in greenhouse were very different along the meausring locations. It is recommeded that PAD location and FAN capacity should be considered to design the Fan and Pad system in order to provide greenhouse the optimum temperature condition.

• 한국융합학회논문지
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• 제11권10호
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• pp.25-30
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• 2020

본 연구에서는 국가대표 컬링(curling) 선수들이 사용하는 컬링 패드(pad)의 성능을 평가 할 수 있는 시험 장비를 개발 하였다. 개발된 장비는 얼음을 생성 할 수 있는 수조, 수조에서 생성된 얼음 표면에 패드를 밀착시켜 스위핑(sweeping, 패드 왕복 운동)을 수행 할 수 있는 패드 구동 장치 및 얼음 속 온도를 측정 할 수 있는 측정 장치로 구성되었다. 수조와 구동 장치는 챔버(chamber) 형태의 구조물 내부에 설치하여, 챔버 내부 공기의 온도와 습도 조절이 가능하도록 제작 하였다. 개발된 시스템을 이용하여 8종의 컬링 패드에 대하여 스위핑 수행 시 얼음 속 온도 변화를 관찰한 결과, 컬링 패드에 따라 서로 다른 온도 변화가 관찰되었다. 실험을 통하여 관찰된 얼음 온도 상승이 빠른 패드와 선수들이 선호하는 패드가 일치하여, 연구에서 수행한 컬링 패드 스위핑에 의한 얼음 온도 변화를 측정하는 시험방법이 패드의 성능을 가늠하는 유효한 방법임을 확인 할 수 있었다.

• 한국정밀공학회지
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• 제25권8호
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• pp.37-44
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• 2008

Nowadays, the increasing global competition forces manufacturer to reduce the cost and time for implementation of manufacturing system. The AR(augmented reality) technology as a new human-machine interface introduces a noteworthy perspective for a new manufacturing system design. Using AR technology, a physically existing production environment can be superimposed with virtual planning objects. Therefore, the planning tasks can be validated without modeling the surrounding environment of the production domain during short process planning time. In this paper, we introduce the construction of AR browser and determine the optimal environment parameters for field application of AR system through lots of tests. And, many methods such as multi-marker coordinate system, division of virtual objects and so on, are proposed in order to solve the problems suggested from initial field test. Based on these tests and results, the test-bed of C/Pad assembly system is configured and robot program for C/Pad assembly is generated based on AR system.

• Tribology and Lubricants
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• 제38권1호
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• pp.1-7
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• 2022

Chemical-mechanical polishing (CMP) process is a semiconductor process that planarizes a wafer surface using mechanical friction between a polishing pad and a substrate surface during a specific chemical reaction. During the CMP process, polishing pad conditioning is applied to prevent the rapid degradation of the polishing quality caused by polishing pad glazing through repeated material removal processes. However, during the conditioning process, uneven wear on the polishing pad is inevitable because the disk on which diamond particles are electrodeposited is used. Therefore, the abrasion of the polishing pad should be considered not only for the variables during the conditioning process but also when designing the CMP conditioning system. In this study, three design variables of the conditioning system were analyzed, and the effect on the pad wear profile during conditioning was investigated. The three design variables considered in this study were the length of the conditioner arm, diameter of the conditioner disk, and distance between centers. The Taguchi method was used for the experimental design. The effect of the three design variables on pad wear and uniformity was assessed, and new variables used in conditioning system design were proposed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.7-10
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• 2006

본 논문에는 준평형 모델을 사용하는 PAD(propellant actuated device) 시스템의 거동 및 추진제 형상설계에 관하여 기술하였다. 준평형 모델의 검증을 위해 PAD 시스템 시험이 수행되었다. 시험과 해석 결과를 비교하여 상호 경향이 유사함을 확인함으로써 준평형 모델적용치 타당성을 입증하였고, 사용된 시스템의 열손실 및 마찰계수를 얻을 수 있었다. 개발된 설계기법은 향후 PAD 시스템 설계시에 유용하게 사용될 것이다.

• 재활복지공학회논문지
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• 제8권3호
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• pp.161-168
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• 2014

본 연구에서는 Pneumatic air fitting system을 적용한 기립보조기 제품을 뇌병변 소아환자를 대상으로 기립보조기의 신체 고정용 폼패드(foam pad)와 에어패드(air pad) 사용 시, 뇌병변 장애아동들의 체간 및 하지근육의 수축 양상을 비교 분석하였다. 연구결과, 패드(foam pad vs. air pad) 유형에 따른 근육별 근력 활성도는 차이가 있었다. 이러한 차이는 큰 동작(식사동작)에서 크게 나타나고, 작은 동작(쓰기동작, 읽기동작)이 작게 나타났다. 이는 Pneumatic air fitting system을 적용한 기립보조기 제품 사용 시, 기존 폼패드에 비해 사용자에게 좀 더 편안함을 제공하는 것으로 나타났다.

• Journal of Welding and Joining
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• 제21권4호
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• pp.87-91
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• 2003

Effects of the circular and non-circular pad shapes on self-alignment in BGA soldering are predicted using Surface Evolver, and the calculated results are compared with experimental data. While the pad shape has minor effects on self-alignment in the vertical direction, self-alignment in the lateral direction depends on the pad direction and length ratio of the non-circular pad. Larger restoring force is obtained in the minor-axis direction than the major-axis direction, which suggests a possibility of reducing misalignment in the specific direction. The restoring force of the circular pad is between those of the non-circular pad in the major and minor-axis directions. The calculated results of Surface Evolver show reasonably good agreements with experimental data using the shear loading system.

• Tribology and Lubricants
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• 제14권4호
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• pp.29-36
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• 1998

The thermal characteristics of a disk such as temperature distribution, thermal behaviors and thermal stress during a braking operation has been analyzed for a high-speed brake using the finite element method. The maximum stress for a pad loaded against a disk was occurred at the trailing and leading edges of the disk pad at the underlayer-backplate interface. The FEM results indicate that the thermal characteristics of the spot type pad shows good performance compared with those of the flat type pad. Thus, the spot type pad in brake system may be recommended for the high-speed train system.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.245-255
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• 1997

The thermal characteristics of a disk such as temperature distribution, thermal behaviours and thermal stress during a braking operation has been analyzed for a high-speed train using the finite element method. The maximum stress for a pad loaded against a disk was occurred at the trailing and leading edges of the disk pad at the underlayer-backplate interface. The FEM results indictate that the thermal characterisics of the spot type pad shows good performance compared with those of the flat type pad. Thus, the spot type pad in brake system may be recommended for the high-speed train system.