유압 구동시스템용 체크 밸브의 유동특성 및 구조안정성에 관한 연구

우위팅(Yu-Ting Wu),진진(Zhen Qin),곽기명(Gimyeong Gwak),류성기(Sungki Lyu),조용민(Yongmin Cho),백승호(Seoungho Back),박상후(Sanghu Park) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.7

유압 구동시스템은 여러 산업기계에서 널리 사용되며 체크 밸브는 유압 동력전달시스템의 중요한 부품이다. 하지만 유로와 하우징의 부적절한 설계로 인하여 고압의 오일이 전달될 때 체크 밸브의 누유 및 손상과 같은 문제가 빈번하게 나타난다. 이러한 문제를 해결하기 위하여 본 연구에서는 유한체적법(FVM)과 유체 동역학 기반의 수치적 연구 수단을 활용하여 유압 기계에 사용하는 “L”자형 고압 체크밸브를 바탕으로 설계를 평가하였다. 또한 유한요소법(FEM)을 바탕으로 내부 고압을 고려하여 체크 밸브 하우징의 구조적 안정성에 대해 시뮬레이션을 진행하였다. 본 논문에서 사용한 연구방법은 다양한 유압시스템용 체크 밸브에 적용이 가능하며 유압 동력전달 과정의 안전성을 보장하기 위하여 중요한 설계 평가 사례를 보였다. Hydraulic drive systems are widely used in the equipment used in various industries, such as agriculture and construction. The internal check valve is an important part of the hydraulic power transmission system in a hydraulic machinery. Because of improper design of the flow circuit and housing, check valves are exposed to various problems, such as leakage and damage, frequently during high pressure transmission. To solve this problem, the L-shaped high-pressure check valve used in hydraulic machinery was designed and evaluated using the finite volume method and numerical research method based on fluid dynamics. Furthermore, considering the impact of high internal pressure on the check valve shell, the structural stability of the valve was simulated using the finite element method. The research method adopted in this study can be applied to check valves in various hydraulic systems. Additionally, an important design and evaluation example is provided to ensure the safety of the hydraulic power transmission process.

새로운 케이블 감쇠 시스템의 이론 모델에 관한 연구

우위팅(Yu-Ting Wu),진진(Zhen Qin),류성기(Sung-Ki Lyu) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

항공기용 견인봉의 구조적 안정성에 관한 수치 연구

우위팅(Yu-Ting Wu),진진(Zhen Qin),김남용(Namyong Kim),전남술(Namsool Jeon),박상후(Sanghu Park),류성기(Sungki Lyu) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.1

항공기 견인봉은 주로 지상에서 항공기의 견인 작업 및 유지보수 목적으로 사용된다. 작동 중에 과부하, 인적 요인으로 작업 과실 및 환경(지면) 요인의 영향으로 인하여 견인봉 굽힘 또는 파손과 같은 고장 문제가 자주 발생하여 항공기의 정상적인 비행 스케줄에도 영향을 미친다. 이러한 종류의 문제는 비행 중에 발생하지 않지만 높은 발생 빈도로 인하여 항공산업에서는 견인봉의 설계단계에서 구조적 안정성을 매우 중요시하고 있다. 본 연구에서는 소형 무장헬기용 견인봉을 기반으로 모델링 및 수치 연구를 수행하여 최적의 견인봉 구조설계 방법에 대하여 고찰하였다. 실제 작업 극한 조건을 고려하여 각각 특성이 있는 tubular 식 및 solid 식 견인봉에 대하여 구조 강도 평가, 좌굴 임계 하중 분석 및 전단핀 설계를 수행하였다. 본 논문에서 사용한 연구 방법은 다양한 작업 조건 및 견인봉 모델 개발에 적용이 가능하며 항공기의 견인 작업의 안전성을 보장하기 위하여 중요한 설계 이론을 적용하였다. Mainly an aircraft tow bar is used for the operation and maintenance of an aircraft on the ground. Failure problems such as tow bar bending and fracture frequently occur owing to the influences of overload conditions, man-made destruction, and environmental factors. These problems may even affect the normal flight mission of the aircraft during the operation. Although this type of problem does not occur during flight, owing to the high occurrence frequency of this problem, the structural stability of the tow bar in the design stage is of importance to the aerospace industry. In this study, a series of modeling and numerical analyses were carried out to investigate the optimal design method with a high structural stability based on a tow bar for small military helicopters. A structural strength evaluation, ultimate buckling load analysis, and design of the breakaway pin were performed for tubular and solid bar-type tow rods with specific characteristics by considering the actual extreme working conditions and different characteristics of the tubular and solid tow bars. The method used in this study is applicable under various working conditions and for tow bar model development. It provides an important design theory reference to ensure the safety of the towing operation of the aircraft.

노벨 정량 분말 공급 장치의 설계 및 연구

우위팅(Yu-Ting Wu),진진(Zhen Qin),이윤승(Yunseung Lee),류성기(Sungki Lyu),백승호(Seoungho Back),박상후(Sanghu Park) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.8

분말을 친환경적이고 정량적으로 공급하기 위하여 본 논문에서는 노벨 분말 공급 장치의 설계를 제안하고 그 메커니즘 설계 원리에 대해 분석한다. 장치내 분말의 유동 특성을 관찰하기 위하여 분유를 연구 대상으로 선정하였다. 분말 입자 사이의 공극률과 충돌효과를 고려하여 유동영역 내에서 고밀도의 입자 유동 모델을 구축하였으며 Fluent를 활용하여 순간적인 CFD 시뮬레이션을 수행하였다. 무거운 하중을 받는 장치의 구조적 안전성을 고려하여 일련의 유한요소법 기반 구조 강도의 시뮬레이션을 실시하고 메커니즘의 신뢰성을 검증하였다. 또한 3D 프린터를 활용하여 분말 공급 장치의 시제품을 제작하였으며 섭취량 실험을 수행하였다. 결론적으로 제안된 분말 공급 장치는 내부 유동 특성, 구조적 안전성, 실제 분말 공급의 정량 정밀성 등 측면에서 만족스럽다고 평가할 수 있다. 본 연구에서 사용된 설계 및 검증 방법과 다양한 메커니즘의 설계를 위한 유용한 이론을 제시하였다. To precisely feed powders or particles in an environmentally friendly manner, a novel apparatus for powder feeding is proposed. The kinematics and design principles of the mechanism were analyzed. To observe the flow characteristics of the powder in the apparatus, milk powder was selected as the study object. By considering the voidage and collision effect between particles, the dense discrete phase method–discrete element method collision model was established and investigated based on the commercial computational fluid dynamics software ANSYS Fluent. To observe the structural stability of the proposed apparatus under an extreme load condition, a series of finite-element-method-based structural simulations were implemented and the reliability of the design was verified. A prototype was made based on three-dimensional printing technology, and the feeding precision was compared with that of the traditional measuring spoon. The design was satisfactory in terms of flow characteristics, structural safety, and quantitative feeding. The design and investigation methods used in this study can provide an important theoretical reference for the design of a variety of apparatus.

17cc급 자동차용 압축기 내구성능 최적화에 관한 연구

양용군(Yong-Kun Yang),우위팅(Yu-Ting Wu),진진(Zhen Qin),류성기(Sung-Ki Lyu) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.3

The fuel economy is a key issue for the automotive industry due to environmental concerns. In particular, only 5-20% of the energy generated in a car using an internal combustion engine is used as power, and the remaining energy is dissipated due to friction with other parts. The main components in the reciprocating piston type compressors commonly used in general vehicles include shafts, swash plates, pistons, and cylinders, and severe friction loss occurs due to the contact of these components. Generally, the wear contact is the maximum between the shaft and cylinder and between the piston and swash plate. The friction of these parts may cause quality problems and deteriorate the durability. In this study, to reduce the frictional loss, a prototype with additional coating agents was produced. Moreover, an optimized design was generated, and performance, noise, and durability tests were conducted. A more durable product was successfully obtained.

3/8″유압 퀵 커플러의 피스톤형상을 고려한 최적설계에 관한 연구

김남용(Nam-Yong Kim),우위팅(Yu-Ting Wu),진진(Zhen Qin),조용민(Yong-Min Cho),류성기(Sung-Ki Lyu) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.2

A hydraulic quick coupler is a component used to easily connect or disconnect pipes or hoses that transfer high pressure fluid without leakage in various mechanical devices. In this study, to obtain an optimal design of a 3/8" hydraulic quick coupler, the effect of different shapes of the internal piston on the internal flow characteristics of the coupler was analyzed and evaluated through numerical analysis based on computational fluid dynamics. Subsequently, the optimal shape design of the internal piston was obtained by comparing the flow characteristics results such as velocity distribution, temperature distribution, and the pressure drop of the hydraulic quick coupler.

케이블 사장교용 내고온 · 내고압 유압 펌프의 설계에 관한 연구

진진(Zhen Qin),우위팅(Yu-Ting Wu),김동선(Dong-Seon Kim),김상배(Sang-Bae Kim),류성기(Sung-Ki Lyu) 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.11

Hydraulic pumps are widely used in fields such as machinery manufacturing, engineering and construction. Although the research on hydraulic engineering is mature, it is still necessary to examine various performance aspects in detail for specific applications. This paper will focus on the hydraulic pump used in special construction machinery that needs high temperature and high pressure resistance. It will analyze the theoretical design, structure and thermal characteristics of the pump system using the Fundamentals of Engineering (FE) method, and will measure the key tolerance parameters of the hydraulic pump to ensure the accuracy of the machining. Through this research, a good design method for the linear reciprocating type of hydraulic pump can be summarized.

새로운 케이블 감쇠 시스템의 메커니즘 설계에 관한 연구

진진(Zhen Qin),우위팅(Yu-Ting Wu),류성기(Sung-Ki Lyu) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

17cc급 자동차용 압축기 핵심부품의 구조 안정성에 관한 수치적 연구

양용군(Yong-Kun Yang),우위팅(Yu-Ting Wu),진진(Zhen Qin),류성기(Sung-Ki Lyu) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.5

Fuel economy has always been a major issue for the automotive industry due to environmental concerns. In particular, it is known that only 5-20% of the energy generated in a car that mainly uses an internal combustion engine is converted to increase fuel efficiency, many methods have been proposed. Among these methods, weight reduction is most commonly used because it is the simplest and cheapest. Weight is always the main reason for energy consumption, therefore, reducing weight is the best way to increase fuel efficiency while simultaneously saving on material costs. To reduce the weight of a compressor, material substitution is used. However, aluminum (a lighter metal substitute) is more fragile than steel, therefore, structural stability must be verified through testing. In this paper, we performed a 3D analysis to investigate whether aluminum can be used without compromising structural stability. Our investigation included static analysis and thermal analysis. As a result, we found that an aluminum swash plate can be safely applied on a shaft instead of steel; it reduces weight while maintaining stability that is equal to or better than steel.

평면식 유압 커플링 시스템의 유동 특성에 관한 수치적 연구

류성기(Sung-Ki Lyu),우위팅(Yu-Ting Wu),진진(Zhen Qin),조용민(Yong-Min Cho) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.6