• 동력기계공학회지
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• 제22권6호
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• pp.80-86
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• 2018

A damper is a hydraulic device designed to absorb or eliminate shock impulses which is acting on the sprung mass of car body. It converts the kinetic energy of the shock into another form of energy, typically heat. The main mechanism for providing damping is by shearing the hydraulic fluid as it flows through restrictions. Since the damping mechanism depends on the flow restrictions, these restrictions are very important in damper design. Damper engineers often try several combinations of valve shims, piston orifices and bleed orifices before finding the best combination for a particular setup on a car. Therefore, the ability to tune a damper properly without testing is of great interest in damper design. For this reason, many previous researches have been done on modeling and simulation of the damper. This paper explains a genetic algorithm method to find the optimal parameters for the design objective and the simulation results agree well with the targeted damping characteristics.

• 한국소음진동공학회논문집
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• 제20권8호
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• pp.734-741
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• 2010

In this paper, an intake RCV system for low noise turbo engine was developed through optimization process of a geometric path of compressor housing and an open rate of recirculation valve. At first, the critical customer requirement from voice of customer was defined and quality function deployment of an intake RCV system was executed. And then, the renovative concept design using pugh matrix method was selected as final concept for satisfaction of requirement. Simultaneously, system analysis was carried by function diagram and fishbone diagram. Next, control factors and levels for the optimal design were performed. And, the optimal design of an intake RCV system was studied using design of experiment. Conclusively, we achieved not only cancellation tip-out noise at the driving condition but also improvement of NVH commodity through optimization process of an intake RCV system, which is optimal configuration of compressor housing and recirculation valve.

• 산업경영시스템학회지
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• 제32권1호
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• pp.85-93
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• 2009

In this paper, the geometric design for the body of a 3"-PFA-lined plug valve is concerned, and body model which has less deformed PFA-resin after infection molding process is proposed. A CAE software is used to simulate the deformation due to heat in cooling. To reduce the deformation, some small shapes are added to PFA-resin surfaces related on wall of the valve housing. And thermal stress simulation with FEM methodology is followed after that. Also, the 3D-CAD package is used during the design processes. In this study, I tried to present the possibility to use the FEM analysis in the solid modeling process. So, the design engineer will be able to use analysis package effectively on his job within the limited range.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.507-514
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• 2001

Direct drive servovalve(DDV) is a kind of one-stage valve since the rotary motion of DC motor is directly transferred to the linear motion of valve spool through the link. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the classical controller is designed using the analytical Bode method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.629-636
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• 2003

The purpose of this study is localization of safety relief valves for Nuclear Service through technical development with overall design, fabrication, inspection, capacity certification test and functional qualification test of safety relief valves in accordance with ASME Section III and KEPIC Code. Safety relief valve is the important equipment used to protect the pressure vessel, the steam generator and the other pressure facility from overpressure by discharging the operating medium when the pressure of system is reaching the design pressure of the system. But we're depending on technology of the other country up to the present time. Because we don‘ have our own technologies, we have been spent the great time and money on installing and repairing safety relief valve at nuclear power plant. Therefore we have to achieve the development of safety relief valves for Nuclear Service with our own technologies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1590-1595
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• 2003

Direct drive servovalve(DDV) is a kind of one-stage valve since the rotary motion of DC motor is directly transferred to the linear motion of valve spool through the link. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the lead-lag controller is designed using the complex method that is one kind of constrained direct search method.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1719-1726
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• 2004

Direct drive servovalve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the DC motor. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the lead-lag controller is designed using the complex method that is one kind of constrained direct search method.

• 대한기계학회논문집A
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• 제26권4호
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• pp.754-763
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• 2002

Direct drive servovalve(DDV) is a kind of one-stage valve since the rotary motion of DC motor is directly transferred to the linear motion of valve spool through the link. Since the structure of DDV is simple, it is less expensive, more reliable and offers reduced internal leakage and reduced sensitivity to fluid contamination. However, the flow force effect on the spool motion is significant such that it induces large steady-state error in a step response. If the proportional control gain is increased to reduce the steady-state error, the system becomes unstable. In order to satisfy the system design requirements, the classical controller is designed using the analytical Bode method.

• 한국가스학회지
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• 제11권1호
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• pp.23-28
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• 2007

본 본문에서는 LPG 용기용 가스밸브의 O-링과 밸브패킹의 밀봉결함과 크랙에 관련된 실험적 연구를 수행하고자 한다. LP 가스의 누출을 방지하기 위해 사용하는 O-링은 LPG 밸브의 밀봉 안전성을 확보하는 핵심부품으로 대단히 중요하다. 밸브패킹은 LPG 연료의 공급과 충전을 하는데, 가스 공급구를 열고 닫는 중요한 역할을 담당한다. 이들 두개의 밀봉부품에 대한 성능은 밸브의 누설 안전성과 장수명에 밀접한 관련이 있다. 연구결과에 의하면, O-링의 대부분은 파티션 부근의 결합불량과 과도한 압축률로 인해 원주방향으로 크랙이 발생하는 것으로 분석되었다. 그 이외의 결함으로 거론된 경우는 LP가스의 과도한 가스압력으로 인한 압출현상의 발생은 압출크랙을 일으키는 원인으로 작용하고 있다. 따라서 본 논문에서는 가스밸브의 누설 안전성을 확보하고 수명을 연장하기 위해 O-링과 밸브패킹에 대한 엄격한 품질관리와 인증제도의 도입을 권장하고자 한다. 결국에는 LPG용기용 밸브의 품질과 안전성 확보를 위해 밀봉장치에 대한 품질안전 보증제도를 도입해야 밸브를 오랫동안 사용할 수 있을 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1441-1444
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• 1996

This paper presents the position control of a double-rod cylinder system activated by an electrotheological(ER) valve unit. Following the composition of a silicone oil-based ER fluid, theological properties of the ER fluid are experimentally tested as a function of imposed electric fields to determine appropriate design parameters of the ER valve. The ER valves are then designed and manufactured. Subsequently, the pressure drop of the ER valve is evaluated with respect to the intensity of the electric field. Four ER valves bridge-cylinder system is formulated, and the governing equations for the system are derived. A neural network control scheme is then synthesized to perform the position control of the cylinder system. Tracking control responses are experimentally evaluated and presented in order to demonstrate the effectiveness of the proposed control system.