• 한국안전학회지
• /
• 제31권3호
• /
• pp.130-135
• /
• 2016

It is very hard to analyze the train derailment safety quantitatively at the curved section because of the diversified affect parameters including the complex interaction between wheel and rail, the train conditions such as the shape of wheel, suspension system, the track conditions such as the radius of curve, cant, transition curve, and the operation conditions, etc. Two major factors related to the running safety of railway vehicle are classified as the railway vehicle and the track condition. In this study, when the railway vehicle passing through curves of actual track condition of subway line NO.3 in seoul ($Yeonsinnae{\leftrightarrow}Gupabal$), the effect that has influence on running safety depending on rail inclination. The analysis result of 1/40 rail inclination condition is more favorable on running safety than other rail inclination conditions because derailment coefficient and wheel unloading ratio are the lowest.

• 한국산학기술학회논문지
• /
• 제15권6호
• /
• pp.3357-3362
• /
• 2014

본 연구에서는 자동차가 노면을 주행 시 발생되는 진동에너지를 수집하여 차량의 배터리를 자가 충전할 수 있는 현가장치에 적용 가능한 공진형 선형 발전시스템을 설계하였다. 논문에서 제안된 선형 발전기는 기존의 발전기들과는 달리, 비교적 작은 에너지 원천인 노면의 진동에 더욱 효과적으로 대응하기 위해 공진 현상을 최대한 활용하는 설계를 지향했으며, 한정된 공간인 차량 현가장치에서의 선형 발전기의 발전 효과 검증 및 향후 연구 진행의 가능성을 판단하기 위해 수치해석적 방법을 활용하여 시스템의 동적 해석을 위한 기본 입력 속도를 도출하고 시스템의 목표인 발전 기능에 대한 예측을 위해 전자기 유한요소해석을 수행하였다. 본 연구에서 정상적인 발전 기능의 가능성을 확인한 공진형 선형 발전 시스템이 최근 자동차 산업의 큰 주축을 이루고 있는 하이브리드형 자동차 및 전기 자동차에 적용된다면, 각종 전장장치 및 배터리의 구동 및 성능유지에 도움을 줄 수 있을 것이다.

• 대한기계학회논문집A
• /
• 제29권2호
• /
• pp.270-276
• /
• 2005

This paper develops the flexible computational model of a heavy truck by interfacing the frame modeled as a flexible body to the heavy truck's computational model composed of rigid bodies. The frame is modeled by the finite element method. Three torsional modes and three bending modes of the frame are considered for the interface of the heavy truck's computational model. The actual vehicle test is conducted off road with a velocity of 20km/h. The vertical accelerations at the cab and front axle are measured in the test. For the verification of the developed computational model, the measured vertical acceleration profiles are compared with the simulation results of the heavy truck's flexible computational model. E grade irregular road profile of ISO is used as an excitation input in the simulation. The verified flexible computational model is used to compare the vibration characteristics of a front suspension system having a multi-leaf spring and that having a tapered leaf spring. The comparison results show that the front suspension having a tapered leaf spring has a higher vertical acceleration at the front axle but a lower vertical acceleration at the cab than the suspension system having a multi-leaf spring.

• 한국자동차공학회논문집
• /
• 제8권6호
• /
• pp.111-121
• /
• 2000

Generally, the hydraulic pressures are used for transmitting the force. Therefore, a highly reliable and inexpensive control system has been required for a passenger car. The control-ability of active suspension system is strongly affected by the performance of pressure control valve in the view of dynamic response and energy consumption. In this study, we suggested main design parameters for the optimum design of proportional pressure control valve. The mathematical simulation model was derived from the quarter type model which consisted a valve and hydraulic damper for the purpose of analyzing the valve characteristics. Experiments were performed to confirm the performance of the valve and computations were carried out to ascertain the usefulness of the developed program. The results from computations fairly coincide with those from experiments. This has been achieved by developing the servomechanism valve which comprises the simple combination of a solenoid, a spool valve and a poppet valve. The results from experiments and computations show the development process of optimum proportional pressure control valve in the hydraulics system.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제12권2호
• /
• pp.79-90
• /
• 2012

The torsion beam type of rear suspension has been adopted by most manufactures of small to medium front wheel drive passenger cars. Previous studies analyzed only the load characteristics of CTBA(the coupled torsion beam axle)'s components. This paper analyzed the results of measurement after measuring loads and displacements, angles when a car equipped with the coupled torsion beam axle is driving in various roads. The most important durability factors for CTBA part are the force and direction of rear CTBA trailing arm. If there are design changes, it was difficult to make a sensor and install each time for measuring the trailing arm forces. After analyzing the loading histories between body and chassis, we developed the transformation matrix that can be converted to mutual force. This paper also deals with the analysis of the force behavior through the analysis of the influence and correlation between the body and chassis parts of cars.

• Tribology and Lubricants
• /
• 제29권3호
• /
• pp.180-185
• /
• 2013

The purpose of this study was to analyze the tribological characteristics of the Electronic control suspension System in a car. In the first example, the cilp used to attach the front electronic control suspension(ECS) system's control actuator was fastened very tightly. Thus, the wire was cut because of continual rotation of the shock-up shover piston rod used to adjust the height of the car. This verified the disconnection phenomenon where wire damaged makes it impossible for the ECS system to send signal to the actuator. The second example, involved a minute hole that allowed gas to leak from the ECS system. As a result, the height of the car verified the down phenomenon. In the third example, the resistance of a wire measured at $0.21{\Omega}$, when the G sensor was disconnected from the system. This verified the system shutdown and lighting of the ECS warning lamp because of body interference caused by a slight pressure on the battery cover. Therefore, quality control is always necessary to ensure safety and durability of a car.

• 로봇학회논문지
• /
• 제11권2호
• /
• pp.83-91
• /
• 2016

Most of outdoor mobile robots have a suspension on each wheel in order to relieve the shock by ground obstacles and to improve the driving stability. Typically, in the actual operations, the suspensions have been used under a given set of conditions as all the damping and spring coefficients of the suspensions are fixed. However, it is necessary to readjust the coefficients of the suspensions according to surface conditions that may cause the unstable shaking of a robot body at high speed driving. Therefore, this paper is focused on the mobility analysis of an outdoor robot when the coefficients of suspensions (in particular, damping coefficients) are changed while driving on an uneven road surface. In this paper, a semi-active suspension with twelve damping coefficient levels was used and a small sized vehicle with the suspensions was employed to analyze the mobility dependent on a change of the damping coefficient. And the mobility was evaluated through driving experiments on a bumped slope.

• 한국소음진동공학회논문집
• /
• 제12권7호
• /
• pp.542-549
• /
• 2002

Computer simulation is essential to design the suspension elements of railway vehicle. By computer simulation, engineers can assess the feasibility of given design variables and chance them to get a bettor design. Even though commercial simulation codes are used, the computational time and cost remains non-trivial. Therefore, malty researchers have used a mesa model made by sampling data through simulation. In this paper, four mesa-models for each index group such as ride comfort, derailment Quotient, unloading radio and stability index, are constructed by use of neural network. After these meta models are constructed, multi-objective optimization are achieved by using the differential evolution. This paper shows that the optimization of design variables using the neural network model is very efficient to solve the complex optimization Problem.

• Advances in Computational Design
• /
• 제4권3호
• /
• pp.307-326
• /
• 2019

A low computational cost semi-analytical method is developed, based on eigenfunction expansion, to study the vibration of rectangular plates subjected to a series of moving sprung masses, representing a bridge deck under multiple vehicle or train moving loads. The dynamic effects of the suspension system are taken into account by using flexible connections between the moving masses and the base structure. The accuracy of the proposed method in predicting the dynamic response of a rectangular plate subjected to a series of moving sprung masses is demonstrated compared to the conventional rigid moving mass models. It is shown that the proposed method can considerably improve the computational efficiency of the conventional methods by eliminating a large number of time-varying components in the coupled Ordinary Differential Equations (ODEs) matrices. The dynamic behaviour of the system is then investigated by performing a comprehensive parametric study on the Dynamic Amplification Factor (DAF) of the moving loads using different design parameters. The results indicate that ignoring the flexibility of the suspension system in both moving force and moving mass models may lead to substantially underestimated DAF predictions and therefore unsafe design solutions. This highlights the significance of taking into account the stiffness of the suspension system for accurate estimation of the plate maximum dynamic response in practical applications.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 추계학술대회 논문집
• /
• pp.240-243
• /
• 2001

Recently, many automobile parts produced by semi-solid forming(SSF) process has been applied for improved weight reduction, better environmental protection and energy savings. SSF process was well developed for high volume production of light weight aluminum components. In this paper, knuckle has been manufactured with A357 by SSF and thor investigated for microstructures and mechanical properties followed by various heat-treatment conditions. It was found that the examined microstructure was equiaxed at the whole cross-section area and as a result, the mechanical properties were satisfied by 100MPa YS, 260MPa UTS and $14\%$ elongation.