• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.181-182
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.59-60
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• 2011

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.7-16
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• 2020

This study presents an acoustic technique to estimate the hydraulic conductivity of soils. Acoustic attenuation and propagation velocity spectra were measured for dry and saturated sandy specimens to confirm that the relationship between Biot's characteristic frequency and its associated hydraulic conductivity exists only for saturated soils. From the experiments presented in this paper, both attenuation-based and propagation-velocity-based techniques resulted in almost identical characteristic frequencies for saturated soils. The propagation velocity based measurements, however, show a a a slightly clearer trend compared to the attenuation based measurements. The results also show that the acoustically estimated hydraulic conductivities of soils agree well with constant head laboratory test results, demonstrating that this acoustic technique can be a useful nondestructive tool to estimate the hydraulic conductivity of sandy or silty soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.185-192
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• 2000

Recently, the hydraulic fill method is commonly used in many reclamation projects due to lack of fill materials. The method of hydraulic fill in reclamation is executed by transporting the mixture of water-soil particles into a reclaimed land through dredging pipes, then the dredged soil particles settle down in the water or flow over an out flow weir with the water. In the present study, practice each three method in order to suggest method of determining the loss rate of the dredged fills. The first sieve and hydrometer analysis were performed with the soil samples obtained before and after dredging and then apply theory of particle breakage, the second compare with the volume of dredged soil between at the dredging area and the target pond and the last compare with weight of dredged soil between before and after dredging at the dredging area and in the target pond for estimating the amount of soil particles residual at the reclaimed area and the loss of soil particles passed through the weir. In addition to compare with the loss ratio between as using Marsal's modified theory of particle breakage and measured weight and volume in the field.

• Geomechanics and Engineering
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• v.16 no.2
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• pp.159-168
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• 2018

In this study, a real-time grouting management system based on the clogging theory was established to manage injection procedure in real time. This system is capable of estimating hydraulic permeability with the passage of time as the grout permeates through the ground, and therefore, capable of estimating real time injection distance and flow rate. By adopting the Controlled Injection Pressure (CoIP) model, it was feasible to predict the grout permeation status with the elapse of time by consecutively updating the hydraulic gradient and flow rate estimated from a clogging-induced alteration of pore volume. Moreover, a method to estimate the volume of the fractured gap according to the reduction in injection pressure was proposed. The validity of the proposed system was successfully established by comparing the estimated values with the measured field data.

• Structural Engineering and Mechanics
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• v.49 no.6
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• pp.793-810
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• 2014

This research work deals with the development of a new Triangular finite element for the linear analysis of plate bending with transverse shear effect. It is developed in perspective to building shell elements. The displacements field of the element has been developed by the use of the strain-based approach and it is based on the assumed independent functions for the various components of strain insofar as it is allowed by the compatibility equations. Its formulation uses also concepts related to the fourth fictitious node, the static condensation and analytic integration. It is based on the assumptions of tick plate.s theory (Reissner-Mindlin theory). The element possesses three essential external degrees of freedom at each of the four nodes and satisfies the exact representation of the rigid body modes of displacements. As a result of this approach, a new bending plate finite element (Pep43) which is competitive, robust and efficient.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.29-38
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• 1999

In this paper the forming simulation of circular bulge by using PAM-STAMP has been performed to estimate the sheet metal forning and the plastic deformation characteristic of circular bulge. The uniaxial tension tests adn bulge tests are carried out for studying the forming characteristics of materials, and also Moire experiment are carried out for measuring the radius of curvature of the bulge and the polar compressive thickness strain. In order to compare the simulation results with the experiment and Hills theory, the relationships between redius of curvature adn polar height of the bulge, between hydraulic pressure and polar height, and between polar compressive thickness strain and polar height, are used. According to this study, the results of simulation and Hills theory are good agreement to the experiment. So, the results of simulation by using PAM-STAMP and Hills theory will give engineers good information to assess the formagbility and plastic deformation characteristic of hydraulic circular bulge test.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.57-64
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• 1993

A modified kinematic wave model of the overland flow in vegetated filter strips was developed. The model can predict both flow depth and hydraulic radius of the flow. Existing models can predict only mean flow depth. By using the hydraulic radius, erosion, deposition and flow's transport capacity can be more rationally computed. Spacing hydraulic radius was used to compute flow's hydraulic radius. Numerical solution of the model was accomplished by using both a second-order nonlinear scheme and a linear solution scheme. The nonlinear portion of the model ensures convergence and the linear portion of the model provides rapid computations. This second-order nonlinear scheme minimizes numerical computation errors that may be caused by linearization of a nonlinear model. This model can also be applied to golf courses, parks, no-till fields to route runoff and production and attenuation of many nonpoint source pollutants.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.151-157
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• 2000

The MRAC theory has proved to be one of the most popular algorithms in the field of adaptive control, particularly for practical application to devices such as an hydraulic servosystem of which parameters are unknown or varying during operation. For small sampling period, the discrete time system becomes a nonminimal phase system. The $\delta$-MRAC was introduced to obtain the control performance of nonminimal phase system, because the z-MRAC can not control the plant for small sampling period. In this paper, $\delta$-MRAC is applied to the control of an hydraulic servosystem which is composed of servovalve, hydraulic cylinder and inertia load.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.280-289
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• 2008

This paper presents design of the quantitative feedback control system of the three axes hydraulic road simulator with respect to the dummy wheel for uncertain multiple input-output(MIMO) feedback systems. This simulator has the uncertain parameters such as fluid compressibility, fluid leakage, electrical servo components and nonlinear mechanical connections. This works have reproduced the random input signal to implement the real road vibration's data in the lab. The replaced $m^2$ MISO equivalent control systems satisfied the design specifications of the original $m^*m$ MIMO control system and developed the mathematical method using quantitative feedback theory based on schauder's fixed point theorem. This control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) having the minimum bandwidth for parameters of uncertain plant. The efficacy of the designed controller is verified through the dynamic simulation with combined hydraulic model and Adams simulator model. The Matlab simulation results to connect with Adams simulator model show that the proposed control technique works well under uncertain hydraulic plant system. The designed control system has satisfied robust performance with stability bounds, tracking bounds and disturbance. The Hydraulic road simulator consists of the specimen, hydraulic pump, servo valve, hydraulic actuator and its control equipments