• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1818-1822
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• 2008

Generally, not only in order to design three dimensional hydraulic structures such a spillway and to investigate the hydraulic phenomena concerning hydraulic facilities, but also to grasp shape and stability, we simulate actuality phenomenon through hydraulic model experiments. However, it requires too much times, expense and space to perform hydraulic model experiments, as well as it is very difficult to measure reduced scale of actual hydraulic structures. Besides, surface tension can exert fair effect in experiment result, and occasionally an experiment of various case is impossible actually. Therefore, there is necessity to draw proper early result through numerical analysis, and if decide the case of a hydraulic model experiment through the numerical analysis and compare the result, finally economical and reasonable design hydraulic structures are available. This study performs numerical analysis of overflow spillway and an experimental study of hydraulic model tests to design the optimal spillway and suggest a better design to improve hydraulic conditions. From the measurements, revised designs for an hydraulic structure are suggested and consequent improvement effects by the new design are also investigated.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.4
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• pp.21-27
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• 2007

A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. Therefore the prediction of impact energy in design process is very helpful to the most of breaker manufacturers. In this study, we carried on modeling and simulation of a hydraulic breaker to predict impact energy via commercial CAE software. The modeling and simulation of a hydraulic breaker was achieved with two parts. One is a hydraulic circuit analysis part via AMESim and the other is impact strain analysis part via ANSYS.

• International Journal of Safety
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• v.10 no.2
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• pp.1-5
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• 2011

The structural integrity assessment of APR1400 (Advanced Power Reactor 1400) reactor vessel internals has been being performed referring the US Nuclear Regulatory Commission regulatory guide 1.20 comprehensive vibration assessment program prior to commercial operation. The program is composed of a hydraulic and structural analysis, a vibration measurement, and an inspection. This paper describes the hydraulic and structural analysis on the reactor vessel internals due to hydraulic loads caused by the turbulence of reactor coolant. Three-dimensional models were built for the hydraulic and structural analysis and then hydraulic loads and structural responses were predicted for five analysis cases with CFX and ANSYS respectively. The structural responses show that the APR1400 reactor vessel internals have sufficient structural integrity in comparison with the acceptance criteria.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.45-52
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• 2013

PURPOSES : This study is to construct the regression models of drainage asphalt concrete specimens and to provide the appropriate coefficients of hydraulic conductivity prediction models. METHODS: In terms of easy calculation of the hydraulic conductivity from porosity of asphalt concrete pavement, the estimation model of hydraulic conductivity was proposed using regression analysis. 10 specimens of drainage asphalt concrete pavement were made for measurement of the hydraulic conductivity. Hydraulic conductivity model proposed in this study was calculated by empirical model based on porosity and the grain size. In this study, it shows the compared results from permeability measured test and empirical equation, and the suitability of proposed model, using regression analysis. RESULTS: As the result of the regression analysis, the hydraulic conductivity calculated from the proposal model was similar to that resulted from permeability measured test. Also result of RMSE (Root Mean Square Error) analysis, a proposed regression model is resulted in more accurate model. CONCLUSIONS: The proposed model can be used in case of estimating the hydraulic conductivity at drainage asphalt concrete pavements in fields.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.4
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• pp.1-11
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• 2013

Unsaturated hydraulic conductivity function is one of key parameters to solve the flow phenomena in problems of landslide. Prediction models for hydraulic conductivity function related to soil-water retention curve equations in many geotechnical applications have been still used instead of direct measurement of the hydraulic conductivity function since prediction models from soil-water retention curve equations are attractive for their fast and easy use and low cost. However, many researchers found that prediction models for the hydraulic conductivity function can not predict the hydraulic conductivity exactly in comparison with experimental outputs. This research introduced an inverse analysis to evaluate the hydraulic conductivity function corresponding to experimental output from the flow pump system. Optimisation process was carried out to obtain the hydraulic conductivity function. This research showed that the inverse analysis with flow pump system was suitable to assess the hydraulic conductivity in unsaturated soil, and the prediction models for the hydraulic conductivity were led to the significant discrepancy from actual experimental outputs.

• Journal of KSNVE
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• v.9 no.1
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• pp.42-48
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• 1999

In this paper, a computer simulation method for dynamic analysis of the hydraulic engine mount system is proposed. The hydraulic engine mount system controls the damping characteristics using the viscosity of fluid flow The complex stiffness of the main rubber of the hydraulic engine mount system is computed by finite element analysis for the viscoelastic materials and hydro-static elements. A numerical analysis method is presented to solve nonlinear equations of the hydraulic engine mount system. which is composed of an engine mass, fluid in inertia track and a vertical inertia force of reciprocating mass in the engine. Also. dynamic properties of the hydraulic engine mount system are analyzed in the frequency domain. Effects of the hydraulic engine mount system running over the rough road are investigated using a vehicle dynamic model. These results are compared with those of the rubber mount system.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1E
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• pp.42-48
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• 2002

In this paper, a computer simulation method is presented far the dynamic analysis of a hydraulic engine mount system. The hydraulic engine mount system controls the damping characteristics using the viscosity of fluid flow. The complex stiffnesses of the main rubber for the hydraulic engine mount system are computed using a finite element analysis. The equations of motion considering the parameters of the hydraulic engine mount system are derived. To investigate the effects of the hydraulic engine mount system, the computer simulation running over a typical rough road is carried out using a vehicle dynamic model. These results are compared with those of the conventional rubber mount system.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.189-196
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• 2000

In this study, the hydraulic breaker system was analyzed and the analysis tool using GUI was developed. The analysis on the system with the accumulator was included. from the parametric analysis, the effects of each factor were revealed. Through the simulation with varying parameters, the method to improve the performance of the hydraulic breaker system was presented. The analysis tool will help a man without special knowledge about programming analyzse the hydraulic breaker system. The result of this study will help improve the hydraulic breaker system in sight of "Blow energy" and "Blows per minute".ws per minute".uot;.

• Journal of Applied Reliability
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• v.9 no.3
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• pp.177-193
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• 2009

Hydraulic breakers, the attachment devices of the excavators, refer to a machine that converts back and forth motions of pistons into energies to break objects down finely. As the use of hydraulic breakers has been steadily increasing world-wide, consumers have become more interested in not just the quality of hydraulic breakers but their reliability. This study show functions and usages of several main parts on hydraulic breakers. In addition, based on the effect of action of hydraulic breakers, FMEA was performed to figure out the major causes and manifestations of malfunctioning. As above mentioned, we analyzed reliability of hydraulic breakers by models, and the data that had been used for the analyses were obtained from malfunctioning data in the field.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.929-935
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• 2018

This paper develops a flow control block for a hydraulic system of a tunnel boring machine. The flow control block is a necessary component to ensure stability in the operation of the hydraulic system. In order to know the pressure distribution of the flow control block, the flow analysis was performed using the ANSYS-CFX. It was confirmed that the pressure and flow rate were normally supplied to the hydraulic system even if one of the four ports of the flow control block was not operated. In order to evaluate the structural stability of the flow control block, structural analysis was performed using the ANSYS WORKBENCH. As a result, the safety factor of the flow control block is 1.54 and the structural stability is secured.