• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.51-56
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• 2002

In this paper, the stress and deformation characteristics of the high pressure hose that have the hose components such as rubber, braid and steel( sleeve and nipple) during the manufacturing process, and analyzed using the [mite element method The swaging process is modeled with a contact problem in identical conditions of real circumstances, and the properties of hose materials based on the experimental data are used in this analysis. Also, to understand the effect of the nipple protrusions on the deformation characteristics of a power steering hose among the steel materials shape of the existing model, and changed the steel materials shape partially, and compared with the existing model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.91-96
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• 2010

The hydraulic hose can be divided with the low pressure, the medium pressure, and the high pressure hose according to the applied pressure. The power steering system in a passenger car can be divided with the high pressure and the low pressure hose. This study deals with the life prediction for high pressure hose to be given impulse pressure which was generated in turning the car. To adjust with external and internal condition, impulse pressure and oil temperature need to be controlled with impulse test system. The result, which is only controlled with the pressure and oil temperature, adapted Calibrated Accelerated Life Test(CALT) method to predict the life of the high pressure hose and analyzed the swagging part by finite element method during the impulse test.

• Corrosion Science and Technology
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• v.3 no.5
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• pp.209-215
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• 2004

Flexible hydraulic hose assembly that consists of hose and joints is used widely on various construction heavy equipments, agricultural machines, motor vehicles, and industrial heavy machines that require flexibility on hydraulic pipelines. It is classified by the maximum usage pressure which is determined by the winding layers of coiling steel wire and the inner diameter of the hoses. In this paper, we designed and performed an accelerated life test for assessing the reliability of a flexible hydraulic hose assembly. In the proposed accelerated life test, typical impulse pressure testing method is applied with the half omega flexing operation to simulate the practical flexing motion of the hose assembly.

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.37-42
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• 2003

The mechanical components with high-pressure hoses are generally produced by the swaging process. The hoses are composed of the rubber materials and the reinforced braids to support tensile forces. In case they are subjected to high mechanical and thermal loads under severe operating conditions, the oil in hoses can leak at the parts of small clamping forces. In this paper, the deformation characteristics of a fiber-reinforced hose are analyzed with respect to the jaw strokes using the finite element method. The manufacturing process is modeled with a contact problem in consideration of a real situation, and the material properties based on the experimental results are used in the analysis. Examinations of the relationship between the swaging strokes and the deformation behaviors of the hose were made on the basis of the stress and strain values of the hose components. The relations between clamping forces and separating forces are also proposed, in order to estimate clamping forces corresponding to separating forces for the given model.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.786-791
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• 2003

We have studied on the main causes of pressure drop in the paint hose under the spraying with airless spray pump and suggest calculation method for selecting the optimum pressure drop during the spraying. Among many factors contributing the pressure drop during the airless spraying procedure of paint, some of the key factors and the correct method for checking pressure loss between airless pump and spray gun are addressed. We have developed pressure loss calculation method which depending on hose length and diameter, viscosity and flow rate in the painting hose during the spraying. also we have developed calculation equation for the expected spray tip flow rate which depending on pressure and specific gravity and tip size.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1156-1159
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• 2017

The various ground support equipments are necessary for KSLV-II ground operation at the assembly building located in Naro Space Center. Among the various ground support equipments, the launch vehicle connection unit and high pressure flexible hose are important elements, because they are used for connection between the ground compressed gas supply system and the launch vehicle. In this paper, the development progress of the launch vehicle connection unit and high pressure flexible hose are introduced.

• Fire Science and Engineering
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• v.27 no.3
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• pp.52-59
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• 2013

It was described the measured friction loss depending on pressure used and changes in water flow rates for a fire hose used at a fire scene on this study. As a result of actual measurement based on the result obtained by analyzing the use situation of a fire hose such as the kind, quantity, pressure used, etc. of a fire hose, the friction loss in a fire hose under the condition of using by a fire officer at a fire scene was measured as up to 56.8 %. This is much different from the equivalent length of a fire hose used to calculate the pump head in an indoor and outdoor fire-fighting facility. There is no related restrictive regulation on friction loss, there are even no data on friction loss measured by fire hose makers, and spreading a fire hose without considering friction loss at a fire scene can result in an increased length of hose used and a high-pressure water discharge from a fire engine, so this study aims to establish a standard for an equivalent length to friction loss in a fire hose and to propose a spreading method considering friction loss in a fire hose at a fire scene.

• Journal of Korea Foundry Society
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• v.20 no.3
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• pp.181-187
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• 2000

There are two types of vacuum die casting, one is known as the chill block method, and the other is the valve block method. Efficiency of the valve block method is better than the chill block method. However purchasing and maintaining cost of the former one is very high, the latter method is popular in many small and medium die casting shops. Simple evacuation system using chill vent was prepared to investigate the effect of the air pressure, hose length and chill vent type on the pressure change in die cavity in this study. The rate of evacuation was influenced by the evacuation method, chill vent condition and hose length. Evacuation time became longer and vacuum level lower when evacuating cavity via chill vent. It took a longer time to evacuate the cavity when a longer hose was used. Vacuum level in the cavity also decreased with increase in hose length.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.1
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• pp.10-16
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• 2004

The failures such as leakage and burst stemmed from the repetitive motions of bending and stretching of the assembly of hydraulic hose in construction machines, agriculture machines, vehicles, and industrial heavy machines can induce big troubles. Therefore, the hydraulic hose itself eventually requires an estimation of life to operate the hydraulic system safely. In this research, we have qualitatively selected the efficient test items by the analysis of the life and potential failures of hydraulic hose. We have used more than seven of hydraulic hoses simultaneously for the research. We have applied impulse pressure and half omega flexing motions to the accelerated life testing Test results have been expressed by employing weibull plot.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.93-100
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• 2006

The failure of hydraulic hose assemblies is caused by the impulse pressure and repetitive motions of bending and stretching (flexing) used at high pressure pipe in the form of bursting Since it takes long time to observe the bursting for life analysis, we can reduce test time by the method of applying the Knockdown stress which is equivalent to 70% of initial bursting pressure on rubber hose assemblies with maintaining the failure mode equally In this study, after scale parameter, shape parameter, and acceleration factor by preforming the impulse pressure test until the hose bursts, and finally analyzed the accelerated life.