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RISS 인기검색어
- 검색키워드
- 저자 : 우종식(Jong-Shik Woo) (검색결과 5 건)
- 무료
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- 유료
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A Numerical Calculation of the Hydrodynamic Pressure Problem
우종식(Jong-Shik Woo) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_2
전산 유체역학(CFD: Compulational fluid dynamics)은 최근에 수압 연륜 문제의 해를 구하는데 새로운 예측 도구로 선택되고 있다. 젖은 노면에서 타이어의 속도는 Hydroplaning 이라는 현상을 유도 시키는 가장 큰 요소로 인식되고 있따. 이 논문에선, CFD의 방법의 하나인 Finite Volume Method 를 이용하여 타이어 속도가 50과 70km/h 일 때 타이어 표면에 나타나는 수압을 계산하는 모델링을 제시한다. 3차원인 비정상적인 점성인 비압축성 난류 모델을 이용하여 수압의 예측과 타이어 Groove 가 갖는 배수성을 예측하는 모델을 선정하였다. 수압은 타이어와 노면 사이의 공간을 압축하여 발생하게 한다. 이 때 타이어 표면은 이동 경계 조건을 이용하여 아래쪽으로 움직이게 한다. 타이어 표면에 나타난 예측된 수압은 실험값에서 보여준 일반적인 분포도와 일치하여 본 모델링의 실용도를 보여준다.<br/> Computational Fluid Dynamics(CFD) has been recently chosen as a simulation tool for the hydrodynamic pressure problems. On the wet rood, the speed of a traveling tire is a critical factor to induce dynamic hydroplaning phenomenon. In this paper, a CFD code using a finite volume method is used to evaluate hydrodynamic pressure at the tire surface when tire speed is given at 50 and 70km/h. The three-dimensional unsteady viscous incompressible turbulent flow is modeled to predict hydrodynamic pressure and mass flow rates through the tire grooves. The pressure is created by squeezing the space between the tire and rood surface. The tire surface moves downward generated by the moving<br/> boundary condition. The predicted hydrodynamic pressure shows a reasonable variation of the pressure distribution on the tire surface.<br/>
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손정삼,이홍우,조진래,우종식,Son Jeong-Sam,Lee Hong-Woo,Cho Jin-Rae,Woo Jong-Shik 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10
The most important factor of the traffic accident on the wet road is a tire slip caused by hydroplaning. Meanwhile, hydroplaning characteristics are influenced very greatly by the vehicle velocity, so it is very important to reveal the relation between hydroplaning and the vehicle velocity. Since the experiment study is considerably limited, recently the numerical simulation using finite element method(FEM) and finite volume method(FVM) is widely adopted. In this paper, the effect of the vehicle velocity on the hydroplaning characteristics is investigated through the hydroplaning analysis using MSC/Dytran.
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타이어 롤링해석을 활용한 타이어마모량 예측에 관한 연구
최주형(Joo-Hyoung Choi),조진래(Jin-Rae Cho),김기전(Gi-Jeon Kim),우종식(Jong-Shik Woo) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
Tire wear of automobile is considered as an important factor to decrease the breaking and cornering performance. However, the tire rubber materials have been developed on an empirical basis up to the present time. Furthermore, one of the most expensive tests is the highway abrasion test. In this aspect, the numerical simulation approach is currently being widely employed. In this paper, we investigated the factors affecting the tire wear based on the mechanism of abrasive wear, and we found that the tire wear is closely related to frictional energy. Accordingly, the frictional energy is computed by utilizing the 3D dynamic rolling analysis of patterned tire. Finally, the amount of tire wear is predicted by correlating frictional energy with the wear equation.
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전도형(Do-Hyung Jeon),최주형(Joo-Hyung Choi),조진래(Jin-Rae Cho),김기전(Gi-Jeon Kim),우종식(Jong-Shik Woo) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
This study is concerned with the braking distance estimation using frictional energy rate. First, steady state rolling analysis is performed, and using this result, the braking distance is estimated. Dynamic rolling analysis during entire braking time period is impratical, so that this study divides the vehicle velocity by 10㎞/h to reduce the analysis time. The multiplication of the slip rate and the shear stress provides the frictional energy rate. Using frictional energy rate, total braking distance is estimated. In addition. ABS(Anti-lock Brake System) is considered, and two type of slip ratios are compared. One is 15% slip ratio for the ABS condition. and the other is 100% slip ratio which leads to the almost same braking distance as the elementary kinematic theory. A slip ratio is controlled by angular velocity in ABAQUS/Explicit. A 15% slip ratio gives the real vehicle's braking distance when the frictional energy occurred at disk pad is included. Disk pad's frictional energy rate is calculated by the theoretical approach,
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1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-substituted Benzenesulfonate 유도체의 합성
우종식,이천수,박현수 啓明大學校 産業技術硏究所 1989 産業技術硏究所 論文報告集 Vol.11 No.-
Pyrazolate[1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-toluenesulfonate] has been introduced recently as a moiety of a novel pre-emergency treatment herbicide for the control of annual and perennial paddy weeds with low phytotoxicity to riceplant. It is known that pyrazolate herbicide is effective at very low concentrations, and it also has some advantages on the ecological and toxicological side. From this point of view, this research has been attempted to develop new pyrazolate analogs which can displays slowly their effect of ten decomposing of their compounds. 1,3-Dimethyl-4- 2,4-dichlorobenzoyl)-pyrazol-5-yl p-substituted benzenesulfonates were prepared by the reaction of p-substituted benzenesulfonyl chlorides with 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-hydroxy pyrazole. The structures of these products were characterized by IR, ¹H-NMR and ?C-NMR spectra with 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-acetamidobenzensulfonate(Ⅳ) 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-carbethoxyamidobenzensulfonate(Ⅴ), 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-dimethylcarbamoylamidobenzenesulfonate(Ⅵ) and 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-pyrazol-5-yl p-diethylcarbamoylamidobenzenesulfonate(Ⅶ), respectively.
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