• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1200-1203
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• 2017

Propulsion system test complex (PSTC) is designed to verify propulsion system of KSLV-II. It is composed of hydraulic and pneumatic system, test stand system, control/measurement system, and flame deflector and safety system. In this study, kerosene filling system of hydraulic and pneumatic system is introduced. It performs store and chilling of kerosene, chilling and purging of filling line, and filling and retrieval of the kerosene. The kerosene supply requirements of 1, 2 and 3 stages of KSLV-II are considered in design process.

• Design & Manufacturing
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• v.12 no.3
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• pp.48-54
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• 2018

This paper presents a numerical study for the development of a low-noise low-vibration industrial wheel for non-pneumatic wheel to significantly reduce vibration and noise. For this, design, injection molding and performance testing were performed. Various geometric shapes and materials were taken into account. For numerical analysis, ANSYS, LS-Dyna, and ABAQUS were used to predict the behavior of the wheel under different loadings based on various design changes. Based on this, 4 prototypes were fabricated by changing the design of wheels and molds, and various vibration and noise tests were carried out. A vibration tester was developed and tested to perform the vibration noise test considering durability. A prototype and test of the final wheel was performed. In the case of the vibration test, the vibration levels were 81.16dB and 80.66dB, which were below the target 90dB. Noise levels were 53.20 dB and 52.55 dB below the target 65dB. In the case of the impact resistance test, it was confirmed that there was no change in appearance after impact. The product weight was measured to be 174g compared to the target of 190g.

• Journal of Applied Reliability
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• v.14 no.4
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• pp.230-235
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• 2014

The failure modes of pneumatic directional control valves include leakage, wear of the spool seal, and sticking of the spool. Among them, the main failure mode of the valve is leakage. The leakage is caused by the wear of the spool seal. However, due to the characteristics of the seal material, the leakage rate is fluctuated a lot rather than constantly increased over time. If life analysis is performed using the first time data of leakage failure, predicted life cycles can be different from the real life cycles. This paper predicts life cycles of the pilot pneumatic directional control valve based on the three point moving average which considers the average of the fluctuating leakage rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.836-839
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• 2003

A pneumatic servo valve which is widely applied in industrial field. And It is consist of force motor, spool ＆ sleeve and servo controller. In this study. we developed the force motor which is consume to low power for a pneumatic servo valve. We could reduce the number of turn of the solenoid by using ferromagnetic permanent magnet and took different direction of each other using one coil instead of two coil. we modeled a system consisting of various electro-mechanical subsystems. The appropriateness of the model was verified by simulation. The simulation model resolved the motion of spool, the winding current and the magnetic force. Also, we calculated the displacement and velocity of the spool, flux contour line, b vector. flux density. flux linkage, back EMF etc.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1387-1390
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• 2008

Pneumatic cylinder is widely used in the various industrial fields. Reliability Study of this field is very important part to the related companies. In this study, we want to predict the life of pneumatic cylinder using Cox (or proportional hazards) model. Used in biomedical applications, the Cox model can be used as an accelerated life testing model. We considered working pressure and temperature as stress factors. The statistical software is used to analyze and forecast the life data.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.190-195
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• 2004

An exhaust brake system is composed of a gate valve, a pneumatic cylinder and an on-off solenoid valve. An on-off solenoid valve which is a key component of the exhaust brake system ought to have characteristics such as high reliability and long life for reducing the foot brake and tires damage, and for driver's fatigue relief of middle/large size vehicles running a long distance. In this paper, an on-off solenoid valve which is used for vehicle brake system was studied. For the performance evaluation of the on-off solenoid, electromagnetic characteristics and dynamic characteristics are analyzed. On the basic study for the performance improvement of exhaust brake system, pneumatic circuit and pneumatic valve of on-off solenoid type were suggested and the performance of pneumatic valve through the test procedure was evaluated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.50-55
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• 2011

The fluid power products are widely used in current industrial area such as automation of products and equipment assembly, high-tech machine tool, aircraft, train, and etc. As the development of industry is in progress, the development of the fluid power products is demanding and it is required in every industrial area. This research proposed a pneumatic system to evaluate displacement accuracy of the pneumatic actuator without external load and to analyze capability of integration of the valve system. The pneumatic system consisted of a combination of pneumatic actuator, four two-port valves, two three-port valves, two pressure valve, a check valve, two proximity sensors, and a program logic controller (PLC). The position controller is based on the PLC connected with the proximity sensors. The maximum air pressure applied for tests was $49.05N/cm^2$ and the displacement accuracy of a stroke was measured using a dial gauge. The supply- and discharge-side of air pressure and the length of the stroke of the pneumatic cylinder were varied The test of the position control of the pneumatic cylinder was carried out 50 times at each supply- and discharge-side air pressure of 24.53/34.34, 29.43/39.24, 34.34/44.15, and $39.24/49.05N/cm^2$ and replicated three times. The accuracy of the displacement of the pneumatic cylinder stroke increased as the supply- and discharge-side of air pressure increased with the stroke length of 133mm. Also the displacement accuracy increased as the stroke length increased with the fixed supply- and discharge-side of air pressure of the pneumatic cylinder as 34.34 and $44.15N/cm^2$, respectively. The most accurate displacement of the pneumatic cylinder was obtained at the supplyand discharge-side of air pressure of 39.24 and $49.05N/cm^2$, respectively, and strokes of 170 and 190mm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.11
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• pp.951-966
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• 2017

In this work, numerical analyses are carried out and the behaviors are investigated for three types of double-acting oleo-pneumatic shock absorbers along with the mathematical models proposed in the part I of this work. After presenting each numerical algorithm corresponding to each model, the numerical algorithms are implemented as user-subroutines in MSC/ADAMS commercial multi-body dynamic software. By using the developed user-subroutines, numerical studies are carried out for compression/stretch test as well as drop test. From the comparative studies, we investigated the salient feature of each double-acting oleo-pneumatic shock absorber. Results identifies that it is possible to increase the absorbing efficiency in accordance with the requirements for aircraft landing conditions.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.335-341
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• 1998

In this study, the dynamic characteritics in various loading methods for wear tester were investigated experimentally. As for the dead-weight, the pneumatic, and the hydraulic method, the load control performance against external disturbances was estimated under the several loading conditions like the different sliding speed, the varied normal load, and the misaligument. The hydraulic loading method showed the most stable loading performance of all the loading methods in the experiment.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.137-143
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• 2012

In this study, it was conducted to design each components of vane damper for industrial flow control fan and the flow rates were analysed by experimental and numerical method. Through environmental test, it could be confirmed that the designed vane damper was appropriate. Also, almost identical results with test could be drawn from numerical method. Finally, flow rates of electric and pneumatic actuator were measured by test. As the results, difference of flow rate according to opening ratio was smaller in pneumatic actuator than that in electric actuator.