Tilting Train Research Articles

Out of plane crushing and local stiffness determination of proposed foam filled sandwich panel for Korean Tilting Train eXpress – Numerical study

Abstract Weight saving has been the major concern of rolling stock engineers. Implementing lightweight materials makes it possible not only to save energy but also to increase allowable speed and service loads. Recently, sandwich panels have been used for structural material of the rolling stock. Korean Tilting Train eXpress (TTX) has hybrid body shell which reduced its weight by 39% in comparison with stainless steel body shell. The body shell was made of honeycomb sandwich panels with carbon fiber reinforced skins. This paper studies how great improvement one can achieve in energy absorption and impact strength from foam filling of TTX honeycomb sandwich panel. Among several types of polymeric foams, owing to its low density, stiffness, low water absorption, low heat conduction coefficient and relatively good mechanical strength, polyurethane foams (PU) are used as filler phase. Then crushing strength and local stiffness of the foam filled panel are obtained by mean of FE method. Based on analyses carried out, foam filling of honeycomb core causes many changes in structural behavior of TTX panel such as; increase its mean crushing strength and energy absorption capacity by 232%, and enhance its local stiffness up to 45%. These interesting advantages of foam filling only add about 2% to the car body weight. At the other hand, thinner body shell could be manufactures which gives more spacious car body.

A Study on the Characteristics and the Effective Reduction Methods for the Ground Vibration Due to the Travelling Tilting Train

In this paper, a study on the characteristics and the reduction methods of ground vibration due to the tilting train travelling in the conventional line is carried out. The load transmitted into the ground is computed considering the interaction between the tilting car and the line. This load is then applied in the numerical model for the analysis of ground vibration due to the travelling tilting car. The far-fields of the numerical model are modeled using the dashpot, as one of the most widely used absorbing boundaries in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by the travelling tilting car and the analysis of the blocking effect of the ground vibration by wave barriers are performed. From the numerical analysis, it is shown that the blocking effect of the trench and the barrier filled with soft material is more effective than that of the barrier filled with hard material.

A Study on the Characteristics for the Ground Vibration Due to the Travelling Tilting Train

The development of the tilting train can contribute to solve the economic burden and enhance the transportation means of areas that did not share the benefits of the high speed railway. But the dynamic behavior caused by the interaction between the train and the track as well as the environmental vibrations along the railway should be evaluated to secure the safety of the train and riding comfort. In this paper a study on the characteristics for ground vibration due to the tilting train travelling in the conventional line are carried out. The transmitted load into the ground is computed through a study on the interrelation between the tilting car and the line. This load is applied into the numerical model which is one for the analysis of ground vibration due to the travelling tilting car. The far fields on the numerical model are formed by the absorbing boundary using dashpot, one of the most widely used absorbing boundary in finite element analysis. Using this numerical model, the analysis of the ground vibration characteristics caused by travelling tilting car is performed. From the analysis, it is shown that the transferred load due to the tilting train is larger than that of the conventional train.

팬터그래프-전차선로 접촉부 영상처리 기술 개발

The measurement of dynamic stagger in electric railways is one of the key test parameters to increase speed and maintain safety in electric railways. This paper is introduces a non-contact optical-based measuring instrument of a catenary system in electric railways. The instrument is implemented by utilizing a CCD (Charge Coupled Device) camera installed on the roof of a vehicle for vision acquisition and image processing techniques including the Canny edge detector and the Hough transform to detect contact wires and calculate dynamic stagger. To check the validity of our approach for the intended application, we measured stagger of a overhead wire of a Korea Tilting Train (TTX). The non-contact optical-based measurement system proposed in this paper performs real-time stagger measurement of an activated high-voltage contact wire. By results of this paper, the instrument should be applied to assess performance and reliability of newly developed electric railway vehicles.

고속카메라를 이용한 전차선 압상량 검측 시스템 개발

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

Integrating life cycle costs and environmental impacts of composite rail car-bodies for a Korean train

A coupled Life Cycle Costing and life cycle assessment has been performed for car-bodies of the Korean Tilting Train eXpress (TTX) project using European and Korean databases, with the objective of assessing environmental and cost performance to aid materials and process selection. More specifically, the potential of polymer composite car-body structures for the Korean Tilting Train eXpress (TTX) has been investigated. This assessment includes the cost of both carriage manufacturing and use phases, coupled with the life cycle environmental impacts of all stages from raw material production, through carriage manufacture and use, to end-of-life scenarios. Metallic carriages were compared with two composite options: hybrid steel-composite and full-composite carriages. The total planned production for this regional Korean train was 440 cars, with an annual production volume of 80 cars. The coupled analyses were used to generate plots of cost versus energy consumption and environmental impacts. The results show that the raw material and manufacturing phase costs are approximately half of the total life cycle costs, whilst their environmental impact is relatively insignificant (3–8%). The use phase of the car-body has the largest environmental impact for all scenarios, with near negligible contributions from the other phases. Since steel rail carriages weigh more (27–51%), the use phase cost is correspondingly higher, resulting in both the greatest environmental impact and the highest life cycle cost. Compared to the steel scenario, the hybrid composite variant has a lower life cycle cost (16%) and a lower environmental impact (26%). Though the full composite rail carriage may have the highest manufacturing cost, it results in the lowest total life cycle costs and lowest environmental impacts. This coupled cost and life cycle assessment showed that the full composite variant was the optimum solution. This case study showed that coupling of technical cost models with life cycle assessment offers an efficient route to accurately evaluate economic and environmental performance in a consistent way.

Development of a tilting system for electric multiple unit to speed up on conventional lines

An advanced tilting system for KTT (Korean Tilting Train) was developed and a performance test of the system has been completed. KTT has been constructed to speed up and promise a significant enhancement in service quality on a conventional line. KTT is an electric multiple unit composed of 6 cars running at the design speed of 200 km/h. The tilting system is the core technology of KTT and combined with the conventional bogie system. It has a self-steering mechanism and a swing link. The self-steering mechanism of Z-bar type is free to rotate on the curve and stable to run on a straight line. The swing link mechanism of the bolster enables the carbody to tilt up to 8°. A tilting control system detects a curve with sensors and commands the electro-mechanical actuators to move the bolster through the computer network system. GPS collaborates with the tilting system to perceive the curve previously and enables gradual tilting so as not to violate passenger comfort. The performance of the tilting system has been verified by a trial test running of KTT on a commercial conventional line. The tilting system is ready for commercial use.

Structural Safety Evaluation of the Hybrid Composite Bodyshell for Korean Tilting Train by a Whole Body Test

This paper explains the structural safety evaluation of a hybrid composite train carbody. The composite carbody with length of 23m was manufactured as a sandwich structure composed of a 40mm-thick aluminum honeycomb core and 5mm-thick woven fabric CF1263 carbon/epoxy face. In order to evaluate the structural safety of it, the dynamic force of ±0.2g was applied to the full weight carbody by two 50-ton capacity hydraulic actuators. The excitation frequency was determined by the first bending natural frequency evaluation test under full weight condition. The test was conducted for 2x106cycles. During the test, the nondestructive tests using X-ray for the composite body structure and liquid penetrant test for the welding region of the steel underframe were performed.

Low frequency motions and motion sickness on a tilting train

Tilting trains have been developed to reduce rail transport times by allowing greater train speeds without increased discomfort from increased lateral acceleration. It is reported that passengers on tilting trains experience motion sickness, but there have been few published studies of motions of tilting trains and the associated sickness. This paper presents the motion and motion sickness on an experimental tilting train during two trials: the first involved 200 subjects on five return journeys, the second involved 445 subjects and 14 return journeys. For each journey, lateral and vertical translational accelerations and roll velocities were measured in the passenger car-body. Simultaneously, subjects assessed their motion sickness at periodic intervals using an illness rating scale. The characteristics of the translational acceleration and roll velocity were investigated for each journey and the covariant relationships between the low frequency motions were explored. Illness ratings were found to be correlated with the vertical acceleration and roll velocity. A single motion variable is considered insufficient to predict motion sickness on tilting trains.

Structural Assessment for Bogie Frame of 180km/h Korean Tilting Train

This paper has performed the fatigue strength evaluation for the bogie frame of Korean tilting train. In order to verify the structural safety of the bogie frame, we firstly investigated the loading condition imposed on the bogie frame. The bogie frame of the tilting train is exposed to the more severe loadings compared with the conventional one because of the tilting of the carbody and the high-speed curve negotiation. We have conducted some multi-body dynamic analyses to extract the load condition by tilting on curve. The finite element analysis is used to obtain the stress distribution. Through this study, we could make sure the safety of the tilting bogie frame.

지상환경하에서 복합재료의 물성저하를 고려한 한국형 틸팅열차 하이브리드 차체 구조물의 정적안정성 평가

In order to evaluate the static stability of hybrid carbody structures of Korean Tilting Train eXpress(TTX) caused by degradation of composites under ground environments, T300/AD6005 graphite/epoxy composite specimens were exposed to accelerated environmental conditions including ultraviolet radiation, temperature and moisture for 2000 hours. It was found that the stiffness and strength of composites after aging were lower than those of unexposed specimens, and decreased as the aging time increases. The values of the degraded properties were used in the static analysis to check the static stability of hybrid carbody structures caused by environmental degradation of composites. The results shown that the structural stability of hybrid carbody structures was affected by the degradation of composites after exposure to accelerated aging environments.<br/>

Evaluation of the structural integrity of hybrid railway carriage structures including the ageing effects of composite materials

In order to examine the structural integrity of hybrid railway carriage structures of Korean Tilting Train eXpress due to the degraded properties of composite materials under ground environments, T300/AD6005 graphite/epoxy composite specimens were exposed to accelerated ageing conditions including ultraviolet radiation, temperature and moisture for 2000 h. It was found that the mechanical properties of composite specimens after exposure to accelerated ageing environments were lower than those of unexposed specimens, and decreased as the ageing time increases. The values of the degraded properties were used in the structural analysis to check the design requirements of hybrid railway carriage structures caused by environmental degradation of composite materials. The results show that the structural integrity of hybrid railway carriage structures is affected by the degradation of composite materials during its mission life under ground environments.

3202 車体傾斜付き車両の乗り心地向上 : その2 空気圧シリンダの構造と特性(OS.6 運動・振動とその制御)

3202 車体傾斜付き車両の乗り心地向上 : その2 空気圧シリンダの構造と特性(OS.6 運動・振動とその制御)