• Steel and Composite Structures
• /
• 제32권4호
• /
• pp.467-478
• /
• 2019

Running safety and ride comfort of high speed railway largely depend on the track geometry that is dependent on the bridge deformation. This study presents a theoretical study on mapping the bridge vertical deformations to the change of track geometry. Analytical formulae are derived through the theoretical analysis to quantify the track geometry change, and validated against the finite element analysis and experimental data. Based on the theoretical formulae, parametric studies are conducted to evaluate the effects of key parameters on the track geometry of a high speed railway. The results show that the derived formulae provide reasonable prediction of the track geometry change under various bridge vertical deformations. The rail deflection increases with the magnitude of bridge pier settlement and vertical girder fault. Increasing the stiffness of the fasteners or mortar layer tends to cause a steep rail deformation curve, which is undesired for the running safety and ride comfort of high-speed railway.

• International Journal of Railway
• /
• 제2권4호
• /
• pp.147-151
• /
• 2009

Railway vehicles equipped with semi-active suspension system can improve the ride quality of car bodies. Semi-active suspension system is usually applied onto high speed train, and therefore higher running safety requirement is proposed. The influence of semi-active suspension system on safety of vehicles running on straight line and curve line is studied, and the influences of sky hook damping coefficient and system time-delay on operation safety of cars fitted with semiactive suspension system is analyzed. The results show that the vehicles equipped with semi-active suspension system, not only the vibration of car body is decreased, it can also give little influence on running safety of cars, as a result, it will not endanger the running safety of cars.

• International Journal of Internet, Broadcasting and Communication
• /
• 제9권2호
• /
• pp.37-41
• /
• 2017

In the development of means of transportation, human beings who walk, ride or ride carriages are now enjoying the benefits of many means of transportation, including bicycles, airplanes, trains, buses, and cars. In the case of automobiles among various means of transportation, there is an advantage that an individual can conveniently move while possessing it. To solve air polution problems at the same time, eco-friendly automobiles such as low-noise, low-pollution, and high-efficiency automobiles have emerged. However, in the case of eco-friendly vehicleJ, engine noise at low speeds is a noise that is unlike existing vehicles and poses a threat to the safety of pedestrians. In this study, virtual engine system has been developed to prevent engine accidents caused by low- The pedestrians are aware of the fact that the vehicle is approaching.

• 한국자동차공학회논문집
• /
• 제5권5호
• /
• pp.20-26
• /
• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• Journal of Mechanical Science and Technology
• /
• 제17권7호
• /
• pp.958-965
• /
• 2003

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness (NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer In this study, we used the virtual proving ground (VPG) approach for obtaining the dynamic characteristics. The VPG approach uses a nonlinear dynamic finite element code (LS-DYNA3D) which expands the application boundary outside the classic linear static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental results, and the feasibility of the integrated CAE analysis methodology was verified.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1994년도 추계학술대회 논문집
• /
• pp.414-419
• /
• 1994

In recent years, there has been an increasing intest in control of active automotive suspension systems with a goal of improving the ride comfort and safety. Many approaches for these purposes have used linearized models of the suspension's dynamics, allowing the use of linear control theory. However, the linearized model does not well descriibe the actual system behavior which is inherently nonlinear. The object of this study is to develop a neuro controlled active suspension for the ride quality improvement. After obtaining active control law using optimal control theory, we use the artificial neural network to train the neuro controller to learn the relation of road input and control force. Form the numerical results, we found that back propagation learning does show good pattern matching and vertical acceleration of the driver's seat and sprung mass.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.1545-1561
• /
• 2008

Among all transportations, railway transports have been promisingly offering excellent energy conservation and travelling time. Inevitably, they become a main role in not only transport goods but also passengers. With leap in development of technology, trains have tremendously enhanced their services in terms of speed, accessibility and comfort. However, the safety and ride quality have become a main issue as the train speed increased. The higher speeds have led the structural dynamics and health must be monitored from time to time to ensure that they are in good condition to provide reliable ride. Among all monitoring systems, the structural health monitoring (SHM) systems are imperative important due to its capability of in-situ monitoring and inherently reduce the maintenance frequencies and the huge associated cost. In this paper, SHM systems and the related non-destructive test and evaluation methods were discussed. The types of damages related to train vehicles as well as the damage hot spots are also included in this paper.

• 한국인터넷방송통신학회논문지
• /
• 제23권3호
• /
• pp.113-118
• /
• 2023

최근 건강을 위해 자전거 타는 사람들이 많아지고 자전거로 출퇴근하는 사람들이 늘어나면서 자전거 사용자가 많아졌다. 하지만, 사용자가 늘어나면서 사고가 많이 발생하고 있으며, 자전거 사고 대처가 불안정하다. 안전 장비를 제외하고는 다른 방법으로 사고를 대비하기엔 미비하다. 따라서 현대 성인들의 안전하고 편리하게 라이딩할 수 있는 방편이 필요하다. 본 연구에서는 다른 앱과는 달리 안전 기능을 추가하여 라이딩을 하면서 블랙박스 촬영을 할 수 있고, 사고다발구역임을 알려주는 기능이 구현된다. 또한, 안드로이드 내장 센서를 이용하여 사고를 감지하고 자동으로 비상 연락을 취할 수 있는 기능도 추가된다. 자전거 사용자들이 다양한 앱들을 추가로 이용할 필요 없이 하나의 앱에서 안전과 편리성을 확보할 수 있다. 게다가 라이딩 커뮤니티 게시판을 통해 라이딩에 대해 이야기를 나눌 수 있고, 자신의 이동경로를 공유할 수 있는 앱 시스템을 개발한다.

• 한국안전학회지
• /
• 제13권2호
• /
• pp.13-21
• /
• 1998

This is a study on the natural vibration characteristics of Vehicle frame. Nowadays, many trucks freight the over-load, do the car designers consider the over-load about 200% in the design. It's necessary to make the model of a vehicle and simulate it for the test of driving condition, durability and vibration behavior before the vehicle is manufactured. If it is possible to make a simulation using the static and dynamic analysis, this is very useful in accomplishing an optimal design of the vehicle. In this paper, we studied the vibration characteristics of a truck body frame. The automobile body frame model for experiment is made smaller than real size frame with the ratio of 1/10. The vibration characteristics of a frame is considered as one of main factors in analyzing and improving the problem for ride comfort, noise and vibration reduction. Therefore, we experimented two method to neglect the nonlinearity. First is bolting and second is welding at the joint section. We compared computer simulation results and experimental data.

• 한국의류산업학회지
• /
• 제18권4호
• /
• pp.498-508
• /
• 2016

The purpose of this study is to develop an aesthetic and functional bicycle wear for new senior women in their 50s and 60s. Based on the results of the survey, we developed bicycle wear that is friendly to bicycling posture and reflects the preference of new senior women. The results are as followed: First, emphasis is placed on the simple and functional design of the experimental wear consisting of jacket and pants. Jacket is different from the color scheme with the armhole princess line in order for the waistline to look slim. Pants are designed to hold the leg muscles tightly in order to help reduce the muscle fatigue on the bicycle ride. Second, cutting lines and coloring materials are used for the wearer to look slim and the safety of the wearer is planned to secure by inserting the reflective material along the cutting lines on the bicycle ride. Third, the pattern of the experimental wear is designed in consideration of the riding motion of the bicycle. Jacket is designed to have back length longer than front length as compared to the bicycle wears available on the market. Sewing lines in the armpit are designed to be eliminated in order to move the arms smoothly on the ride. Pants are designed to minimize the seam line in consideration of the movement of muscles and ligaments and the experimental wear is produced by combining the material with the functions of cool comfort and stretch.