• Geomechanics and Engineering
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• 제10권5호
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• pp.657-676
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• 2016

In this paper, the active lateral earth pressure is evaluated using the stress characteristics or slip line method. The lateral earth pressure is expressed as the lateral earth pressure coefficients due to the surcharge, the unit weight and cohesion of the backfill soil. Seismic horizontal and vertical pseudo-static coefficients are used to consider the seismic effects. The equilibrium equations along the characteristics lines are solved by the finite difference method. The slope of the ground surface, the wall angle and the adhesion and friction angle of the soil-wall interface are also considered in the analysis. A computer code is provided for the analysis. The code is capable of solving the characteristics network, determining active lateral earth pressure distribution and calculating active lateral earth pressure coefficients. Closed-form solutions are provided for the lateral earth pressure coefficients due to the surcharge and cohesion. The results of this study have a good agreement with other reported results. The effects of the geometry of the retaining wall, the soil and soil-wall interface parameters are evaluated. Non-dimensional graphs are presented for the active lateral earth pressure coefficients.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.457-464
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• 1999

The active earth pressure on the retaining wall is reduced by 3-Dimensional effects of the ground. Therefore, the test was focused on reducing the earth pressure on the retaining wall by inserting the vertical reinforcement in the backfill ground to develope the 3-Dimensional effects. Model tests in sand were peformed to measure the 3-Dimensional effects of the vertical reinforcement on the active earth pressure and its distribution and results were compared with the theories. The size of the vertical reinforcement, the geometry of the backfill space, and the wall friction of vertical reinforcement were varied. It was observed that the active earth pressure and its distribution on the underground structure were affected by the size of the vertical reforcements and wall friction.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.150-158
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• 2002

Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

• 한국지반공학회논문집
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• 제19권1호
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• pp.191-199
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• 2003

강성 옹벽에 작용하는 주동토압은 뒷채움재에서 발생하는 아칭효과로 인하여 삼각형이 아닌 비선형의 분포형태를 보인다. 따라서 뒷채움재에서 발생하는 아칭효과를 고려함으로써 평행이동하는 강성옹벽에 작용하는 주동토압의 비선형 분포를 산정할 수 있는 새로운 토압산정식이 제안되었다. 본 논문에서는 $\phi$와 \delta$, 그리고 옹벽의 높이가 새로운 제안식에서 계산되는 토압의 크기와 분포형태에 미치는 영향을 알아보기 위하여 매개변수 분석을 수행하였다. 그리고 제안된 토압산정식에 대한 정확도를 검증하기 위하여 새로운 제안식에서 얻어진 결과들이 기존의 시험결과 및 기존 제안식들의 결과들과 비교되었다. 예측치와 측정치의 비교를 통해서 새로운 토압산정식은 평행이동하는 강성 벽체에 작용하는 주동토압의 크기와 분포형태에 대하여 만족스런 결과를 주는 것으로 나타났다. 또한 새로운 토압산정식의 사용성을 높이기 위하여 수정 주동토압계수와 주동토압의 작용점 높이에 대한 간편한 설계도표가 제시되었다.

• 소음진동
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• 제7권3호
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• pp.427-437
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• 1997

Mean active intensity based active control for the cancellation of radiated noise out of the duct exit is studied. The active intensity control strategy is drerived based on the relation of the exterior sound field out of the duct termination and interior sound field of the duct. One of the characteristics of this control strategy is that the control performance can be maintained regardless of the sensor loction, compared with the conventional local pressure control methods at either interior downstream or exterior field positions. It is also suggested that the digital filtering for the active intensity control can be achieved by time-domain filtered-x LMP (Lest-Mean-Product) adaptive algorithm. Experiments for an open-ended duct are performed to compare the active intensity control performance with conventional pressure control one. Active control experiment of local sound pressure is conducted by widely used filtered-x LMS adaptive Algorithm and active intensity control implementaion uses the derived filter d-x LMP algorithm. It is shown that the exterior sound fileds was much better observable by sensing of the active intensity than by just sound pressure. It is also demonstrated that the global control performance of external field by acoustic intensity is superior to the conventional sound pressure control performance.

• 한국지반공학회논문집
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• 제19권1호
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• pp.181-189
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• 2003

일반적으로 강성 옹벽에 작용하는 주동토압은 Rankine이나 Coulomb의 토압이론에 의하여 계산되며, 이들 이론에서는 옹벽에 작용하는 주동토압이 삼각형으로 분포한다고 가정한다. 그러나 많은 실험결과들은 벽면이 거친 강성 벽체에 작용하는 주동토압은 Rankine과 Coulomb 이론에서 사용된 가정과는 달리 비선형으로 분포한다는 것을 보이고 있다. 그리고 이러한 비선형의 토압분포는 옹벽의 뒷채움재에서 발생하는 아칭효과 때문으로 알려져 있다. 몇몇 연구자들은 강성벽체의 뒷채움재에 발생하는 아칭효과를 고려한 주동토압 산정식을 제안하였다. 그러나 이들 제안식들은 몇가지 점에서 문제점을 갖고 있다. 따라서 본 연구에서는 평행이동하는 강성벽체에 작용하는 주동토압의 크기와 비선형 분포를 정확히 예측할 수 있는 새로운 토압산정식을 제안하였으며, 이 제안식에서는 뒷채움재에서 발생하는 아칭효과의 영향이 고려되었다.

• 한국정밀공학회지
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• 제23권7호
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• pp.108-113
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• 2006

Recently, Automobile manufactures have developing automotive exhaust system under consideration for improvement in engine performance. It thus develop many exhaust components. For example active muffler, semi-active muffler, electronic muffler etc. In this components consider enhanced back pressure and reduction noise. Especially, In recent years it develop the study of semi-active muffler. Semi-active muffler is simple structure and excel performance. Recently many forms semi-active muffler was developed and adopted to the actual use in consideration of cost and technical side for noise and vibration. This study had main objects about the recently developed the semi-active muffler. It was to show its combustion performance as well as its enhanced back pressure characteristics in design. Therefore if the precise analysis of the combustion pressure according to the back pressure transmission was carried out, it was understood that this study would be utilized in the design of the exhaust system such as the semi-active muffler.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.443-450
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• 2002

It is known that the distribution of the active earth pressure against a translating rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the present paper, a new formulation for calculating the active earth pressure on a rigid retaining wall undergoing horizontal translation is proposed. It takes into account the arching effects that occur in the backfill. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the total active earth force on the translating wall.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2528-2530
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• 2005

In this paper, a study on the analysis and design of an electro-hydraulic pressure reducing valve for active suspension system of car is fulfilled. Also, the structurally improved direct-acting electro-hydraulic pressure reducing valve is proposed to satisfy the performance that active suspension system requires. To prove the possibility whether the proposed valve can be used for active suspension system or not, the mathematical modeling and analysis for this valve is fulfilled and the experiment of response to controlled pressure is achieved. Here we conformed the response speed to controlled pressure of the structurally improved valve changed for the better by modifying the shape of spool such as the structure which make use of the power of controlled pressure derived from the area difference between two section areas of valve spool.

• 한국자동차공학회논문집
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• 제2권3호
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• pp.75-84
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• 1994

In general direct-operated pressure reducing valves have been gardly applied to a dynamic control system such as active suspension control because of their poor control stability. But they are more robust than pilot-operated type and do not need pilot control flow. In this paper development of a new direct-operated proportional pressure reducing valve for low-band type active suspension control is reported. By means of a special damper directly linked to the valve spool, the control stability could be effectively improved without drawback in response time. The linearity error was less than $\pm$3.5%. Applied to an experimental active suspension system the new valve showed the $-90^{\circ}$ phase delay at 4Hz with 20% sinusoidal signal input and could control the suspension system with almost same performance as that with a pilot-operated type valve.