• 한국기계가공학회지
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• 제10권2호
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• pp.67-72
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• 2011

Solvent-free paint is sprayed from higher-pressure conditions, because the viscosity is large. The hydraulic actuator which can be operated under higher-pressure condition is required to spray solvent-free paints in painting process for the environmental protection. The purpose of this paper is to develop the hydraulic actuator under higher-pressure conditions for solvent-free paint spraying system. The hydraulic actuator consists of inner spool, outer spool and ball. The analysis of a structural stability was conducted by using ANSYS V11 under the design condition of upward and downward movement of spool. As a result, the maximum von-Mises stress applied on spool under 4mm displacement showed a value of 106MPa which was greater than the allowable stress of the spool with a value of 250MPa and a value of safety factor 3. This result suggested that the spool system be unstable under the design condition so that it was necessary for the spool system to be reinforced to secure the structural stability.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.38-43
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• 2019

In this study, a hydraulic press structure has been investigated in order to enhance the precision machining and the productivity, which are generally damaged by the structural deformation from the pressure and the vibrations originated from the centrifugal forces from the rotating parts of the machine. Computer simulation based on the finite element method has been utilized for the analysis of static and dynamic characteristics to investigate each component's critical points, and to further improve the static and dynamic stabilities of a hydraulic press structure. The result shows that the deformations and the vibrations of the machine could be reduced 35% without increasing the weight of the machine.

• 한국기계가공학회지
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• 제20권4호
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• pp.24-30
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• 2021

In this paper, a structural stability analysis of the swash plate hydraulic piston pump installed on hydraulic supply systems in marine vessels is presented. In order to verify the integrity of the pump design, a standard structural analysis technique based on the finite element method has been applied for various operating and boundary conditions. For the maximum operational torque (223 N·m) at 5°, 10°, and 15° of the swash plate angle, the maximum deformation, equivalent stress and safety factor are evaluated. The analytical results show that under current operating conditions, the structural reliability of the design has been confirmed.

• 한국정밀공학회지
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• 제11권5호
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• pp.33-41
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• 1994

For the establishment of large force standard and the accurate measurement of large force, 2MN hydraulic force standard machine which consists of loading frame, deadweight machine, two ram/cylinder systems and hydraulic control system was designed and fabricated. Measurement results of shapes for tow ram/cylinders reveal that the ratio of effective area is 200.094. The relative deviation of force stability for the machine is about .+-. 0.01% at 2MN and is less than .+-. 0.005% below 2MN. This machine may be widely used to calibrate the force measuring devices in industry and to test the force sensors.

• Structural Engineering and Mechanics
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• 제54권1호
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• pp.121-133
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• 2015

The aluminum dome has been widely used in natatorium, oil storage tank, power plant, coal, as well as other industrial buildings and structures. However, few research has focused on the structural behavior and design method of this dome. At present, most designs of aluminum alloy domes have referred to theories and methods of steel spatial structures. However, aluminum domes and steel domes have many differences, such as elasticity moduli, roof structures, and joint rigidities, which make the design and analysis method of steel spatial structures not fully suitable for aluminum alloy dome structures. In this study, a stability analysis method, which can consider structural imperfection, member initial curvature, semi-rigid joint, and skin effect, was presented and used to study the stability behavior of aluminum dome structures. In addition, some meaningful conclusions were obtained, which could be used in future designs and analyses of aluminum domes.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.86-92
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• 2003

The hydraulic excavator has been a popular research object for automation because of its multi-workings and economic efficiency. When it works crane tasks, most of disasters happen. The stability of the excavator having crane function has a close relation with excavators posture, motion and load. In this paper, the stability of tipping-over has been analysed using zero Moment point(ZMP)

• 한국정밀공학회지
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• 제21권6호
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• pp.84-93
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• 2004

This study carries out the performance improvement and simplification of hydraulic modulator that plays an important role in vehicle stability control systems. The mathematical models for each component of a modulator, such as pump, wheel cylinder, check and solenoid valve, accumulator, damper are derived in detail. All the mathematical models are combined to form a modulator system and implemented through a computer program, which can be controlled by a user friendly GUI. To verity the simulation, comparison between simulation and experiments has been made. After the verification of the validity of the simulation, the effects of the design parameters of the modulator on the wheel cylinder pressure is investigated. The results show that the modulator without MPA has advantage in early time pressure rise rate, and it can be simplified.

• 한국지반공학회논문집
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• 제28권6호
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• pp.63-70
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• 2012

저강도 강우상태에서 투수계수가 일반적인 절토사면의 흡인력 분포와 안정성에 어떤 영향을 주는지를 평가하였다. 지하수면 위의 불포화 지층의 초기 흡인력을 15 kPa로 가정하였다. 강우 지속시간 증가에 따른 절토사면의 안정성을 평가하기 위해 유한요소법과 한계평형법을 사용하였다. 유한요소 침투해석 결과, 저강도 강우상태에서는 불포화 지층이 계속해서 불포화 상태로 유지되는 현상을 보였다. 또한, 침윤선(wetting front)이 불포화 지층에 남아있는 경우에는 사면의 안정성에 사실상 변화가 없었으나, 침윤선(wetting front)이 지하수면에 도달하는 경우에는 지하수면이 높아짐에 따라 사면안정성이 크게 저하되었다.

• 대한토목학회논문집
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• 제40권1호
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• pp.35-41
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• 2020

본 연구에서는 피복석으로 피복된 저 마루높이 구조물의 안정성을 검토하기 위해 2차원 수리실험을 수행하였다. 피복석 안정성은 구조물 상부, 전사면 및 후사면을 대상으로 파형경사와 여유고를 변화시키며 검토하였으며, 피복석의 주된 피해는 전사면 상부와 바다측 마루부에서 발생하였다. 수행된 2차원 실험결과를 이용하여 파복석의 안정계수 산정을 위한 경험식을 제안하였다.

• 대한토목학회논문집
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• 제40권1호
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• pp.43-49
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• 2020

본 연구에서는 Tripod로 피복된 저 마루높이 구조물의 안정성을 검토하기 위해 2차원 수리실험을 수행하였다. Tripod의 안정성은 구조물 상부, 전사면 및 후사면을 대상으로 파형경사와 여유고를 변화시키며 검토하였다. 수행된 2차원 실험결과를 이용하여 Tripod의 안정계수 산정을 위한 경험식을 제안하였다. 그러나 Tripod는 형상으로 인해 양압력이 Tetrapod와 피복석에 비해 크기 때문에 저 마루높이 구조물의 주 피복재로는 적절하지 않다고 생각된다.