• 한국철도학회논문집
• /
• 제8권4호
• /
• pp.348-353
• /
• 2005

In designing the structures of railway rolling stocks, deterministic methods associated with the concept of a safety factor have been traditionally used. The deterministic approaches based on the mean values of applied loads and material properties have been used as safety verification for the design of rolling-stock car body structures. The uncertainties in the applied loading for the high speed train and the strength of new materials in the rolling stocks require the application of probabilistic approaches to ensure fatigue safety in the desired system. Pressure loadings acting on the car body when the train passes through tunnels show reflected pressure waves for high-speed trains and they may cause a fatigue failure in vehicle bodies. Use of new material technology as body structures also introduces uncertainties in the material strength. A probabilistic approach is more adaptable in designing reliable structures when the pressure waves from the tunnels pounds and new material technology is adopted. In this paper, it is proposed that a fatigue design and assessment method based on a reliability which deals with the loading variations on a railway vehicle due to the pressure reflected in tunnels and the strength variations of material. Equation for the fatigue reliability index has been formulated to calculate the reliability assessment of a vehicle body under fluctuating pressure loadings in a tunnel. Considered in this formulation are the pressure distribution characteristics, the fatigue strength distribution characteristics, and the concept of stress-transfer functions due to the pressure loading.

• 한국정밀공학회지
• /
• 제33권4호
• /
• pp.317-324
• /
• 2016

Stress tests were conducted in the carbody of the railroad car to check the structural strength of the body of the railroad car. The objective of this study was to evaluate safety of the carbody of a railroad car under the maximal strength. The carbody of rolling stock is a principal structure that supports major equipment of the underframe and the freight. Therefore, the strength evaluation of this structure is important. This study was carried out to analyze the structure of carbody and evaluate safety under maximum vertical load, compressive load, and torsional load. Accordingly, stress tests were conducted on the carbody to measure the stress on each of their parts. Before the load test, a structural-analysis program was used for the stress distribution analysis of the body structure.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.2251_2252
• /
• 2009

In this paper, an attempt has been made by incorporating variable wheel arrangement for a car-like robot. In this scheme, the car-like robot controls its body height and the length of forward and backward wheels while driving in omni-direction. Experimental results show that the proposed car-like robot with wheel arrangement variable structure presents effectiveness of several situations.(a. left and right turn, b. longitudinal and latitudinal parking, c. control of body height and the length of forward and backward wheels, d. passing over obstacles, e. adaptive cruise control.)

• 한국인터넷방송통신학회논문지
• /
• 제15권3호
• /
• pp.201-209
• /
• 2015

차대차의 측면충돌에서 충돌부위에 따라 차체의 변형정도는 크게 달라진다. 충돌로 인하여 차체에 변형이 일어나는 경우에 속도에너지가 변형에너지로 전달되어 거동이 달라진다. 일반적으로 교통사고분석에서는 충돌 후 차량의 거동을 운동량 보존법칙으로 분석하며 차체의 변형에 따른 에너지 흡수량은 반발계수를 입력하여 그 오차를 보정할 수 있으나 측면충돌에 대한 연구결과는 그다지 많지 않으므로 전방충돌과 후방추돌에 대한 연구결과를 참고해서 반발계수를 적용하고 있는 실정이다. 본 연구에서는 차체의 구조와 각 부품의 재질을 적용한 유한요소 차량모델을 외연적 유한요소법으로 해석하였으며, 그 결과를 분석하여 측면충돌에서 차량의 접촉부위에 따른 반발계수와 충돌감지시간을 도출하였다. 최종적으로 산출된 반발계수와 충돌감지시간을 적용하여 운동량보존법칙에 의해 얻어진 해석결과를 실제 차량의 충돌결과와 비교하였다. 그 결과로 유한요소해석 모델을 이용하여 도출한 초기 입력값을 적용했을 때 기존의 분석기법보다 해석의 신뢰도가 높다는 결과를 얻게 되었다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
• /
• pp.105-105
• /
• 2000

In this paper, an integrated control of the semi-active suspension system using a reduced full-car model is investigated. By including the reduced full-car dynamics in the control law, the semi-act ive suspension system is able to control not only the vertical acceleration but also the roll and pitch mot ions of the car body, which is not Possible with a quarter-car model or a half-car model. The damping forces for the semi-active dampers are designed to track the damping forces of the skyhook controller designed from the reduced full car dynamics. Computer simulations and experimental results using a real car are also included.

• 한국생산제조학회지
• /
• 제20권2호
• /
• pp.157-161
• /
• 2011

The study for traffic safety improvement is so necessary to minimize the wound of pedestrian at car impact as to prevent pedestrian from this accident. This study aims at analyzing the behavior affected by impact on which car body hits pedestrian. Load and damage of pedestrian are also investigated. This model is the small car body as frame structure. The pedestrian is modeled with dummy by CATIA as Korean standard body style. The ear impacts the side of pedestrian with the speed from 30 to 90km/h. Behavior and damage of pedestrian at impact are analyzed by ANSYS. In case of 30km/h, The maximum pressure of dummy becomes the maximum value of 100MPa after the elapsed time of 0.1second and then seems to remain at 105MPa constantly. In case of 60km/h, its pressure becomes the maximum value of 110MPa at the elapsed time of 0.05second and decreases at 90MPa until the elapsed time of 0.1second. This value fluctuates after the elapsed time of 0.1second. In case of 90km/h, its maximum pressure becomes the maximum value of 155MPa at the elapsed time of 0.07second and fluctuates after the elapsed time of 0.07second until O.3second. This value seems to remain at 100MPa constantly after 0.3second until 0.5second. But this pressure increases suddenly just after 0.5second. Maximum deformations of dummy increase linearly according to elapsed time at hitting velocities of 30, 60 and 90km/h.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
• /
• pp.181-186
• /
• 2002

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows: optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4kW Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. Laser welding has found a place on Hyundai's production plant in conjunction with the startup of mass production of new sports car, and this production system is the result of a collaboration of its engineers. Outer side sheets are joined to inner side sheets by 122 stitch welds totally. And the length is about 2.4meter.

• International journal of advanced smart convergence
• /
• 제11권1호
• /
• pp.94-100
• /
• 2022

It is common for commercial vehicles to make the top part according to the use after making the bear chassis, and to connect various devices with the bear chassis. Various brackets used in bear chassis for the development of all automobiles, including commercial vehicles, play a role of connecting the components required for driving and operating the car to the car body. In commercial vehicles, components necessary for operation are installed in the bear chassis; that is, the bear chassis of commercial vehicles is a space where the devices required for driving and operating the vehicle are installed. The devices required for the configuration of the vehicle are drive, brake, exhaust and steering, etc. These devices are basically connected to the body, the front axis, or the rear axis. The part interlinking the apparatuses required for the vehicle drive to the car body or axis is bracket. In this study, we analyzed the boundary conditions to evaluate the stability of the three brackets that connect the components of the car to the front axis of the new type of 30-seater bus in the development process. In order to analyze the boundary conditions, the boundary conditions according to the driving condition of the vehicle were classified. For stress analysis to evaluate the stability of brackets according to the driving state of the vehicle, it is reasonable to give the bracket a boundary condition of harsh conditions.

• 한국자동차공학회논문집
• /
• 제20권5호
• /
• pp.26-35
• /
• 2012

This paper investigates the influence on the aerodynamic performance of a passenger cruising very fast by some specific car body parts such as side mirrors, wheel arches and wheels designed hardly regarding aerodynamics. The magnitude of the contribution of each part is analyzed via on the CFD simulations. YF SONATA, a sedan of Hyundai Motors Company, plays a major role as the baseline car in this research, representing all passenger car. The CFD analysis condition consists of 6 different cases depending on whether each part exists or not. According to the CFD results, there were confirmed that additionally to the body parts' own drag, the car body went through somewhat the consequential increment of the drag by them. Among the 3 parts, wheel is the magnate that not only has the maximal drag but drives the drag of the passenger car to increase most steeply and the next is the side mirror.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.291-291
• /
• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.