• 한국지반공학회지:지반
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• 제13권5호
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• pp.133-144
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• 1997

기존에 발생된 토석류 퇴적물에 대한 점도실험으로북터 세립질의 성질이 빙함 소성(Bingham plastic) 모델로 표현될 수 있다는 사실이 판명되었다. 이러한 사실과 비뉴톤유체의 흐름을 해석 할 수 있도록 개발된 수치해석 프로그램 Polyflow를 이용하여 토석류의 이동을 해석하였다. 그 결과 실제와 유사한 이동결과가 얻어졌으므로 토석류의 이동은 이와 같은 기법으로 해석할 수 있다는 것을 알게 되었다.

• KSTLE International Journal
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• 제1권1호
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• pp.34-42
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• 2000

A method and results of classification of four different metallic wear debris were presented by using their color features. The color image of wear debris was used far the initial data, and the color properties of the debris were specified by HSI color model. Particles were characterized by a set of statistical features derived from the distribution of HSI color model components. The initial feature set was optimized by a principal component analysis, and multidimensional scaling procedure was used fer the definition of a classification plane. It was found that five features, which include mean values of H and S, median S, skewness of distribution of S and I, allow to distinguish copper based alloys, red and dark iron oxides and steel particles. In this work, a method of probabilistic decision-making of class label assignment was proposed, which was based on the analysis of debris-coordinates distribution in the classification plane. The obtained results demonstrated a good availability for the automated wear particle analysis.

• 한국지반공학회논문집
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• 제38권4호
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• pp.5-20
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• 2022

본 연구에서는 토석류의 유동과 밀도 변화를 분석하기 위해 운동량방정식으로 단순화된 2상 유한체적모델(Landflow 모델)을 구성하였으며, Hershel-Buckley 유동모델을 사용하여 토석류의 내부 및 기저 마찰과 복잡한 지형 및 연행침식을 분석하였다. 또한 토석류 해석 모델을 수치적으로 해결하기 위하여 Harten-Lax-van Leer-Contact(HLLC) 방법을 포함한 관련 유한체적모델을 도입하여 토석류의 경계면에 대한 해를 구하였다. 충격흡수능력, 수치적 등방성, 모델정확도, 질량보존을 검증하기 위해 제안된 모델을 기반으로 원형 댐파괴, 비뉴턴 유체의 댐파쇄 및 다중 토석류 사례분석을 수행하였다. 해석 결과로부터 본 해석모델의 토석류 해석에 대한 수치적 안정성과 정확도를 확인하였다. 또한, 다양한 유동학적 특성의 토석류 흐름을 체계적으로 시뮬레이션하고 토석류 유동특성이 거동에 미치는 영향을 분석하였다.

• 대한토목학회논문집
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• 제39권2호
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• pp.263-272
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• 2019

본 연구는 실제 고속도로 인접지역에서 발생한 토석류를 대상으로 고속도로에서의 토석류 거동을 FLO-2D 모형을 적용하여 재현함으로써, 고속도로에서의 토석류 영향 해석에 대한 FLO-2D 모형의 활용성을 검증하고자 하였다. 대상유역으로는 2005년 8월 집중호우로 토석류가 발생하여 24시간 동안 교통이 차단된 대전-진주간 고속도로의 덕유산 휴게소구간으로 선정하였다. 발생 토석류에 대한 현장조사 및 토성 시험분석 자료를 활용하여 GIS를 이용한 지형분석, HEC-HMS를 이용한 수문분석, 그리고 토석량을 산정하였다. 그리고 나서 FLO-2D 모형의 매개변수 민감도 분석을 통한 최적 매개변수 조합을 선정한 후, FLO-2D 모형을 적용한 토석류 거동해석을 수행하였다. 모형의 예측치와 실측자료와의 비교 분석을 통하여 고속도로에서 토석류 거동해석을 위한 FLO-2D 활용 가능성을 보여주었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.465-466
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• 2002

In any mechanical system consisting of gears, shafts and/or bearings, the majority of metallic particles deposited into and carried by the lubrication system originate from the deterioration of oil-wetted working surfaces, even in proper lubrication system, due to failure mechanism (s) such as wear, fatigue and fretting corrosion. Determination of the point at which transition from normal to abnormal or to actual damage occurs has become a focus of attention in research activities for years, because it has been recognized that reliable, economic operation can be achieved through appropriate preventative measures. Known collectively from 'all size wear debris analysis' as early failure detection, the methods of testing for damage differ considerably, range from a micron or a submicron size debris analysis to Magnetic Chip Detector (MCD) ferrous debris analysis. This paper will be focused on the utilization of the low-cost analysis techniques for evaluation of industrial machinery condition.

• 지질공학
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• 제25권4호
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• pp.439-447
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• 2015

In this study, specific sections vulnerable to debris flow damage were selected, and a complete enumeration survey was performed for the sections with debris flow hazards. Based on this, the characteristics of the sections with debris flow hazards and the current status of actions against debris flow were examined, and an efficient installation plan for a debris flow damage prevention method that is required in the future was suggested. The results indicated that in the Route 56 section where the residential density is relatively higher between the two model survey sections, facilities for debris flow damage reduction were insufficient compared to those in the Route 6 section which is a mountain area. It is thought that several sites require urgent preparation of a facility for debris flow damage reduction. In addition, a numerical analysis showed that for debris barriers installed as a debris flow damage prevention method, distributed installation of a number of small-scale barriers facilities within a valley part was more effective than single installation of a large-scale debris barrier at the lower part of a valley.

• KSTLE International Journal
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• 제3권1호
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• pp.54-59
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• 2002

It can be effective on failure diagnosis of oil-lubricated tribological system to analyze operating conditions with morphological characteristics of wear debris in a lubricated machine. And it can be recognized that results are processed threshold images of wear debris. But it is needed to analyse and identify a morphology of wear debris in order to predict and estimate a operating condition of the lubricated machine. If the morphological characteristics of wear debris are identified by the computer image analysis and the neural network, it is possible to recognize the friction condition. In this study, wear debris in the lubricating oil are extracted from membrane filter (0.45 ${\mu}m$) and the quantitative value fur shape parameters of wear debris was calculated through the computer image processing. Four shape parameters were investigated and friction condition was recognized very well by the neural network.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.646-649
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• 2002

It can be effect on diagnosis of hydraulic machining system to analyze working conditions with shape characteristics of wear debris in a lubricated machine. But, in order to predict and estimate working conditions, it is need to analyze the shape characteristics of wear debris and to identify. Therefor, if shape characteristics of wear debris is identified by computer image analysis and the neural network, it is possible to find the cause and effect of moving condition. In this study, wear debris in the lubricant oil are extracted by membrane filter, and the quantitative value of shape characteristics of wear debris we calculated by the digital image processing. This morphological informations are studied and identified by the artificial neural network. The purpose of this study is In apply morphological characteristics of wear debris to prediction and estimation of working condition in hydraulic driving systems.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.53-58
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• 2003

Wear debris can be collected from the lubricants of operating machinery and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated machinery. But in order to predict and estimate working conditions, it is need to analyze the shape characteristics of wear debris and to identify. Therefore, if the shape characteristics of wear debris is identified by computer image analysis and the neural network, The four parameter (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction. It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debris had a different pattern characteristic and recognized the friction condition and materials very well by neural network. We resented how the neural network recognize wear debris on driving condition.

• 지질공학
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• 제27권1호
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• pp.59-66
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• 2017

최근들어 발생하는 강우는 지금까지의 강우특성과 비교하여 여름철에 단기간 집중적으로 내리는 형태로 바뀌고 있다. 2011년 강원도 춘천지역에서는 이러한 집중강우로 인해 많은 산사태가 발생하였으며, 이로 인해 재산피해와 인명피해를 야기시켰다. 본 연구의 목적은 강우에 의한 산사태 물질의 이동에 대한 특성을 분석하기 위해서 현장 자료와 수치해석 자료를 활용하여 시간에 따른 특성의 변화 및 강우량에 따른 특성의 변화를 분석하는 것이다. 본 연구에서는 항복응력 값의 변화를 통해서 강우량을 재현하였으며, 이를 통해서 어떠한 거동 특성을 보이는지 해석하였다. 그 결과 많은 강우에 의해 항복응력 값이 낮아지는 경우가 빠른 속도의 이동형태를 보이고 동시에 넓은 지역에 걸쳐 확산되는 특성을 확인하였으며, 이러한 결과는 현장에서 확인된 토석류의 흔적과 매우 유사하다는 것을 확인하였다. 본 연구를 통해서 산사태 발생 당시의 토석류 최대 속도 및 최대 두께 등을 파악하는 것이 가능하다.