• 제목/요약/키워드: rolling force model

검색결과 142건 처리시간 0.024초

폭방향 두께제어를 고려한 용탕직접 압연로울의 최적형상 설계기법 (Optimum Shape Design Techniques on Direct Roller of Molten Metal Considering Thickness Control of Width Direction)

  • 강충길;김영도;정영진
    • 한국정밀공학회지
    • /
    • 제14권12호
    • /
    • pp.73-85
    • /
    • 1997
  • The rolling force and roll deformation behavior in the twin roll type strip continuous casting process has been computed to estimate the thermal charcteristics of a caster roll. To calculation of rolling force, the relationship between flow stress and strain for a roll material and casting alloy are assumed as a function of strain-rate and temperature because mechanical properties of a casting materials depends on tempera- ture. The three dimensional thermal dlastic-plastic analysis of a cooling roll has also been carried out to obtain a roll stress and plastic strain distributions with the commercial finite element analysis package of ANSYS. Temperature fields data of caster roll which are provided by authors were used to estimated of roll deformation. Roll life considering thermal cycle is calculated by using thermal elastic-plastic analysis results. Roll life is proposed as a terms of a roll revolution in the caster roll with and without fine failure model on the roll surface. To obtain of plastic strain distributions of caster roll, thermomechan- ical properties of roll sleeve with a copper alloy is obtained by uniaxial tensile test for variation of temperature.

  • PDF

풍동실험에 의한 갠트리 크레인의 풍력계수 산출과 구조 해석 (Wind Force Coefficients Computation of Gantry Crane by Wind Tunnel Experiment and Structural Analysis of the Crane)

  • 이재환;김태완;장인권;한순흥
    • 대한조선학회논문집
    • /
    • 제48권2호
    • /
    • pp.165-170
    • /
    • 2011
  • In this paper, wind force coefficient by wind tunnel experiment is obtained to compute the accurate wind force of the gantry crane model to be used for mobile harbor ship. The first crane model was tested under 20, 30, 40, 52m/s, partially 58m/s and the wind force coefficient is about 2.0 which is very close to the suggested theoretical value. The other is the more reliable crane model and tested under 20, 30, 40m/s also giving the similar realistic wind force coefficient. Also structural analysis of crane model was performed giving the reliable stress level. Since the rolling effect is important for mobile harbor ship, the safety of the crane on the ship needs to be guaranteed. For this, using the computed reaction forces, a tie-down design is suggested which connects the crane and ship to resist the turnover motion of the crane.

Estimation of Vehicle Driving-Load with Application to Vehicle Intelligent Cruise Control

  • Kyongsu Yi;Lee, Sejin;Lee, Kyo-Il
    • Journal of Mechanical Science and Technology
    • /
    • 제15권6호
    • /
    • pp.720-726
    • /
    • 2001
  • This paper describes a vehicle driving-load estimation method for application to vehicle Intelligent Cruise Control (ICC). Vehicle driving-load consists of aerodynamic force, rolling resistance, and gravitational force due to road slope and is unknown disturbance in a vehicle dynamic model. The vehicle driving-load has been estimated from engine and wheel speed measurements using a vehicle dynamic model a least square method. The estimated driving-load has been used in the adaptation of throttle/brake control law. The performance of the control law has been investigated via both simulation and vehicle tests. The simulation and test results show that the proposed control law can provide satisfactory vehicle-to-vehicle distance control performance for various driving situations.

  • PDF

암반강도 및 압입깊이에 따른 디스크커터의 최적간격 산정을 위한 개별요소법 기반 수치해석 연구 (A numerical study on the optimum spacing of disc cutters considering rock strength and penetration depth using discrete element method)

  • 이상연;송기일;정주환
    • 한국터널지하공간학회 논문집
    • /
    • 제22권4호
    • /
    • pp.383-399
    • /
    • 2020
  • 디스크커터의 간격을 최적화하는 것은 TBM 커터헤드의 설계의 핵심요소로, TBM의 굴진성능을 좌우한다. 실대형 선형절삭시험은 디스크커터의 간격 산정을 위해 가장 신뢰성 및 정확도가 높은 시험으로 알려져 있으나 실대형 실험을 위해 경제적 및 시간적 비용이 소요되는 단점이 있다. 본 연구에서는 개별요소법 기반의 수치해석 연구를 통해 암반의 일축압축강도 및 압입깊이에 따른 비에너지-S/P비 간의 경향성을 분석하였고, 17인치 디스크커터의 최적 간격을 도출하였다. 수치해석모델의 적정성을 검토하기 위하여 디스크커터에 작용되는 회전력을 CSM 모델과 비교·검토하였다. 선형절삭시험에 대한 수치해석 결과, 디스크커터에 작용되는 회전력은 CSM 모델의 이론식으로부터 도출한 회전력과 유사한 것으로 분석되었다. 5가지(50 MPa, 70 MPa, 100 MPa, 150 MPa, 200 MPa)의 일축압축강도에 대한 수치해석 결과, 암반강도가 증가할수록 디스크커터의 최적간격의 범위는 감소하는 경향을 보였으며 80~100 mm범위에서 최소 비에너지를 보이는 것으로 확인되었다. 이는, 기존에 보고된 디스크커터의 최적 간격과 일치되는 경향으로써, 본 연구를 통해 산정된 디스크커터 간격을 밑받침한다.

적응 슬라이딩 모드 제어 기법을 이용한 철도차량 대차단위 제동시스템 (A Decentralized Brake System for Railway Rolling Stocks Using the Adaptive Sliding Mode Control Scheme)

  • 박성환;이지민;김종식
    • 대한기계학회논문집A
    • /
    • 제33권10호
    • /
    • pp.1005-1013
    • /
    • 2009
  • In this paper, the performance improvement of a decentralized brake system for railway rolling stocks is investigated. In order to verify the effectiveness of the decentralized brake system, it is compared to the truck unit brake system which has only one control unit per a truck. The adaptive sliding mode control scheme is used to realize a robust anti-slip brake control system. Through computer simulations, it is verified that the decentralized brake system has better braking performance than the truck unit brake system.

파랑상태에 있는 실린더 구조물 주위의 PIV유동 해석 (PIV Analysis on the Flows around a Cylinder under Rolling Wave)

  • 조효제;도덕희;이언주
    • 한국가시화정보학회지
    • /
    • 제9권3호
    • /
    • pp.51-58
    • /
    • 2011
  • The purpose of the study is to provide a foundation in predicting a maximum wave force when the ocean structure is laid out under breaking wave. Experiments were conducted with a down-scaled cylindrical model installed in a wave generating water channel. Maximum wave slopes were changed in regular wave condition by the wave breaker in the water channel. Cylinder's diameters were changed to 0.1m and 0.05m, respectively. Using the PIV results qualitative analyses were performed based upon the previous knowledge.

도상이 장대 레일의 선형 온도 좌굴에 미치는 영향 (Effect of Track Resistance on Linear Thermal Buckling Characteristics of CWR)

  • 강영종;임남형;신정렬;양재성
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
    • /
    • pp.580-587
    • /
    • 1998
  • For many decades, the railway was constructed using tracks with jointed rails of relatively short lengths in accordance with rolling and handling technology. The joints cause many drawbacks in the track and lead to significant maintenance cost. So, railroad engineers became interested in eliminating joints to increase service loads and speeds by improving rolling, welding, and fastening technology, Continuous welded rail(CWR) track has many advantages over the conventional jointed-rail track. But in the case of the elimination of rail joints, it may cause the track to be suddenly buckled laterally by thermal and vehicle loads. Thermal loads are caused by an increase in the temperature of railway track. In this paper, CWR track model and CWRB program are developed for linear buckling analysis using finite element method(FEM). The finite element discretization is used with a total of 14 degrees of freedom for each rail element. The stiffness of the fastener, tie, and ballast bed are included by a set of spring elements. The investigation on the buckling modes and temperature of CWR track is presented in the paper.

  • PDF

장대화물열차의 분산제어 제동 시 연결기에 발생하는 충격력 해석 및 분석 (Analysis and Evaluation of the Distributed Control Braking System of Long Freight Car Brakes)

  • 조병진;이정준;심재석;구정서;문형석
    • 한국기계가공학회지
    • /
    • 제18권2호
    • /
    • pp.65-72
    • /
    • 2019
  • In long freight trains, there is a brake time delay in neighboring freight cars, which causes damage and fractures in the couplers, especially at their knuckle. A problem in the couplers of the cars can cause derailment and damages of human life and property. In this study, maximum forces on the couplers are studied when a long freight car brakes with the brake delay time and coupler gap. We make a dynamic model of 50 freight cars and couplers, applying contact between the couplers and a characteristic curve to express the force and displacement of the buffers using SIMPACK, which is a multi-body dynamics program. We use EN 14531-2, which is a standard of freight car brakes, to verify the dynamic model. Then, we compare the analyzed impact force with the coupler knuckle standard after applying the two carriages of a locomotive in the model based on the dispersed double head control system. The result shows that all coupler gap conditions satisfy the infinite lifetime of the material when the brake delay time is 0.1 second.

대형트럭용 루프 훼어링과 디프렉트의 공기저항력 저감 특성에 관한 연구 (An Effect of Roof-Fairing and Deflector System on the Reduction of Aerodynamic Drag of a Heavy-Duty Truck)

  • 김철호
    • 한국자동차공학회논문집
    • /
    • 제14권2호
    • /
    • pp.194-201
    • /
    • 2006
  • Roof-fairing and deflector system have been used on heavy-duty trucks to minimize aerodynamic drag force not only for driving stability of the truck but also for energy saving by reducing the required driving power of the vehicle. In this study, a numerical simulation was carried out to see aerodynamic effect of the drag reducing device on the model vehicle. Drag and lift force generated on the five different models of the drag reducing system were calculated and compared them each other to see which type of device is efficient on the reduction of driving power of the vehicles quantitatively. An experiment has been done to see airflow characteristics on the model vehicles. Airflow patterns around the model vehicles were visualized by smoke generation method to compare the complexity of airflow around drag reducing device. From the results, the deflector systems(Model 5,6) were revealed as a better device for reduction of aerodynamic drag than the roof-fairing systems(Model 2,3,4) on the heavy-duty truck and it can be expected that over 10% of brake power of an engine can be saved on a tractor-trailer by the aerodynamic drag reducing device at normal speed range($80km/h{\sim}$).

Investigation of the Dynamic Properties of Railway Tracks using a Model for Calculation of Generation of Wheel/Rail Noise

  • Koh, Hyo-In;Nordborg, Anders
    • International Journal of Railway
    • /
    • 제7권4호
    • /
    • pp.109-116
    • /
    • 2014
  • For optimization of a low-noise track system, rail vibration and noise radiation needs to be investigated. The main influencing parameters for the noise radiation and the quantitative results of every track system can be obtained using a calculation model of generation and radiation of railway noise. This kind of model includes contact modeling and the calculation model of the dynamic properties of the wheel and the rail. This study used a nonlinear wheel/rail interaction model in the time domain to investigate the excitation of the rolling noise. Wheel/rail response is determined by time integrating Green's function of the rail together with force impulses from the wheel/rail contact. This model and the results of the study can be used for supporting calculation with the conventional model by an addition of the contributions due to nonlinearities to the roughness spectrum.