• 소성∙가공
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• 제6권2호
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• pp.118-135
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• 1997

In order to analyze the deformation and residual curvature of steel sheets in the strip processing lines, a program for calculating curvature and work hardening of sheet was developed. Strip deformation caused by repeated bending under tension in the process lines was analyzed on the basis of the incremental-plasticity theory with the mixed hardenting model for the purpose of predicting the strip shape and the yield stress change. The developed calculation program was applied to predict curl and gutter of sheets within a 10% difference. The yield stress increment was also predicted with the similar accuracy. Application of the model to tension legvelling process showed that gutter could be controlled by intermesh and elongation. The yield stress increment in the electro-galvanizing line calculated by the developed program was found to be dependent on the yield strength, the applied tension and the diameter of the smallest roll.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.469-472
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• 2000

a crack with electrically impermeable surfaces in an electrostrictive material subjected to uniform electric loading is analysed. A strip yield zone model is employed to investigate the effect of electric yielding on stress intensity factor. complete forms of electric fields and elastic fields for the crack are derived by using complex function theory. /the stress intensity factors are obtained based on the strip yield zone model.

• 한국정밀공학회지
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• 제18권2호
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• pp.186-191
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• 2001

A crack with electrically impermeable surfaces in an electrostrictive material subjected to uniform electric loading is analysed. The effect of electric yielding on stress intensity factor is investigated by using a small scale yielding model and a strip yield zone model. Complete forms of electric fields and elastic fields are derived by using complex function theory. The electrical yield zone shapes for two models are different each other. The two models, however, predict similar yield zone sizes under the small scale yielding conditions. It is found that the influence of electric yielding on the stress intensity factor is insensitive to the modeling of the electrical yield zone shape.

• 한국추진공학회지
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• 제16권5호
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• pp.67-73
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• 2012

고충전 탄성중합체 균열선단에서의 파괴기구를 분석하였으며, 스트립 항복 모델 및 내재결함 모델이 적용되었다. 두 가지 모델의 수정으로부터 고충전 탄성중합체에 대한 파손평가선도의 작성방법이 연구되었다. 고체로켓연료로 사용되는 고충전 탄성중합체의 인장시험 및 파괴인성시험을 수행하였으며, 시험결과로부터 파손평가선도를 작성하였다. 내재결함 모델로부터 작성한 파손평가선도는 스트립 항복 모델로부터 작성한 파손평가선도와의 비교를 위해 정규화되었다. 두 가지 모델로부터 작성한 파손평가 선도를 비교한 결과, 내재결함모델을 이용한 파손평가선도가 스트립항복모델을 이용한 파손평가선도보다 더 보수적으로 파손을 평가하는 것으로 나타났다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.532-538
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• 2012

고충전 탄성중합체 균열선단에서의 파괴기구를 분석하였으며, 스트립 항복 모델 및 내재결함 모델이 적용되었다. 두 가지 모델의 수정으로부터 고충전 탄성중합체에 대한 파손평가선도의 작성방법이 연구되었다. 고체로켓연료로 사용되는 고충전 탄성중합체의 인장시험 및 파괴인성시험을 수행하였으며, 시험결과로부터 파손평가선도를 작성하였다. 내재결함 모델로부터 작성한 파손평가선도는 스트립 항복 모델로부터 작성한 파손평가선도와의 비교를 위해 정규화되었다. 두 가지 모델로부터 작성한 파손평가선도를 비교한 결과, 내재결함모델을 이용한 파손평가선도가 스트립항복모델을 이용한 파손평가선도보다 더 보수적으로 파손을 평가하는 것으로 나타났다.

• 소성∙가공
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• 제25권1호
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• pp.61-66
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• 2016

In the current study, we present a new model for the prediction of the strip profile and the residual stresses. This new approach is an analytical model that predicts the residual stresses from the effect of post-deformation. Since the residual stress cannot exceed the yield strength of the material, post-yielding may possibly occur in the post-deformation zone prior to the strip reaching the steady-state zone. The prediction accuracy of the proposed model is examined through comparison with the predictions from 3-D finite element (FE) simulations.

• 한국방재학회 논문집
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• 제8권4호
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• pp.111-118
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• 2008

수변완충지대는 토지로부터 나오는 오염물질의 하천으로 직접유입을 차단하고 저감하는 역할을 한다. 하지만 현재까지 수변완충지대 설정에 따른 유역에서의 저감효과를 분석하는 사례는 부족한 실정이다. 본 연구에서는 SWAT모형을 이용하여 Arcview GIS상에 병성천 유역 모형을 구축하고 SWAT모형에서의 filter strip기능을 이용하여 수변완충지대 설정에 따른 토사 유출량의 변화를 살펴보았다. 모의결과 저감효과가 큰 곳을 살펴보면 대체적으로 토사유출량 관측지점인 유역 출구지점과 가까운 소유역에서 저감효과가 큰 것으로 보였다. 또한 수변완충지대의 폭을 달리하여 시나리오 분석을 수행한 결과 5-10 m의 수변완충지대 폭이 그 저감효율이 가장 큰 것으로 보였다.

• 한국농공학회논문집
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• 제52권3호
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• pp.97-104
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• 2010

The purpose of this study is to evaluate sediment yield reduction under various field slope conditions with rice straw mat. The Vegetative Filter Strip Model-W (VFSMOD-W) and Soil and Water Assessment Tool (SWAT) were used for simulation of sediment yield reduction effect of rice straw mat. The Universe Soil Loss Equation Practice factor (USLE P factor), being able to reflect simulation of rice straw mat in the agricultural field, were estimated for each slope with VFSMOD-W and measured soil erosion values under 5, 10, and 20 % slopes. Then with the regression equation for slopes, USLE P factor was derived and used as input data for each Hydrological Response Unit (HRU) in the SWAT model. The SWAT Spatially Distributed-HRU (SD-HRU) pre-processor module was utilized, moreover, in order to consider spatial location and topographic features (measured topographic features by field survey) of all HRU within each subwatershed in the study watershed. Result of monthly sediment yield without rice straw mat (Jan. 2000 - Aug. 2007) was 814.72 ton/month, and with rice straw mat (Jan. 2000 - Aug. 2007) was 526.75 ton/month, which was reduced as 35.35 % compared without it. Also, during the rainy season (from Jun. to Sep. 2000 - 2007), when without vs. with rice straw mat, monthly sediment indicated 2,109.54 ton and 1,358.61 ton respectively. It showed about 35.60 % was reduced depending on rice straw mat. As shown in this study, if rice straw mat is used as a Best Management Practice (BMP) in the sloping fields, rainfall-driven sediment yield will be reduced effectively.

• 한국물환경학회지
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• 제30권2호
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• pp.159-165
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• 2014

Vegetative Filter Strip (VFS) is one of effective Best Management Practices (BMPs) to prevent sediment-laden water problem, is installed at the edge of source area such agricultural area so that sediment occurred in source area is trapped by VFS before it flow into stream or river. Appropriate scale of it needs to be simulated before it is installed, considering various field conditions. In this study, a model using VFSMOD-w model and Genetic Algorithm to determine effective VFS length was developed, it is available to calibrate input parameter related to source area sediment yield through thousands of VFSMOD-w simulations. Useful DBs, moreover, are stored in the model so that very specific input parameters can be used with reasonable values. Compared simulated values to observed data values for calibration, R2 and Nash-Stucliffe model efficiency coefficient were 0.74 and 0.65 in flow comparison, and 0.89 and 0.79 in sediment comparison. The model determined 1.0 m of Filter Length, 0.18 of Filter Slope, and 0.2 cm of Filter Media Spacing to reduce 80% of sediment by VFS. The model has not only Auto-Calibration module also DBs for specific input parameters, thus, the model is expected to be used for effective VFS scale.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.39-39
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• 2000

In this paper, a decoupler of tandem cold rolling mill is designed. Before designing the decoupler, this paper improved conventional linear model by considering friction and yield stress of rolling strip. In a stand, the decoupler let an output be controlled by an input. And even if states of other stands should be changed, current stand takes no interference from those changes. In addition, with the same method, a feedforward controller is designed for an input strip thickness error. Finally, performance of controllers above is shown with nonlinear simulation.