Development of a new running gear for the Spectrum intermodal vehicle

The European Union (EU) Seventh Framework Programme (FP7) project Spectrum [12] set out to develop a freight vehicle which would facilitate the exploitation of the low density, high value (LDHV) goods market. Key to the performance criteria for the vehicle were: increased speed to enable mixed running with passenger services; improved ride quality to avoid damage to the LDHV goods; and reduced track damage for longevity and sustainability on increasingly stressed infrastructure. This paper presents aspects of the development of a novel running gear arrangement for the Spectrum vehicle, focussing on the dynamic performance of a Vampire vehicle model and the steps to realising stable running. Finally, the estimated performance of the Spectrum vehicle concept is compared against calculations for a conventional freight wagon with respect to curving, vertical track forces and potential savings in track access charges through implementation of Network Rail’s Variable Track Access Charge Calculator. It was found that the novel Spectrum concept could offer savings in Variable Usage Charges of between 8% and 16% compared to the conventional equivalent

Analysis of Lateral Displacements in Large Railway Viaducts Under Traffic Loads. Impact on Ride Safety and Passenger Comfort.

The increasing design speed of the new high speed lines and the stringent requirements on track alignment parameters are leading to a sustained increase of the number of railway viaducts. The relevant standards impose limiting values on lateral vibrations. Both the Spanish and European standards establish a minimum value for the first natural frequency of lateral vibration of a span, that should not be lower than fh0 = 1,2 Hz. This limit was originally proposed by ERRI committee D181, which assessed the lateral forces in railway bridges. This limit was proposed in order to avoid lateral resonance in railway vehicles going across the structure, taking into account that the frequencies of lateral vibration of railway vehicles are, in general, not greater than 1,0 Hz. In the case of large continuous viaducts with high piers, the lateral deformations occurring during a train pass-by can be significant and the natural frequencies of the first mode of vibration of the deck can be very low. In these cases it is not clear whether the required verifications must be applied to spans considered independently, to several successive spans or to the whole viaduct. There is currently no analysis methodology allowing to assess this situation and check the viaduct design against the requirements of ride safety and passenger comfort. This paper analyzes the lateral deformations of a large continuous viaduct and the infrastructure vehicle interaction effects due to the circulation of freight trains and several types of high speed train sat different speeds. The application of this methodology will allow an optimized design of viaducts with significant lateral deformations that cannot be justified only by using the simplified criteria of the current applicable standards. In such cases, the compliance with standards may lead to over dimensioning or in other cases to neglect the limits without the adequate verification of the proper infrastructure behavior once it has been commissioned. As it is the case for vertical deformations, for which the European standards require the assessment of dynamic effects, we stress the need for a dynamic analysis of the effects of lateral deformations in large railway viaducts

Energy regeneration from suspension dynamic modes and self-powered actuation

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper concerns energy harvesting from vehicle suspension systems. The generated power associated with bounce, pitch and roll modes of vehicle dynamics is determined through analysis. The potential values of power generation from these three modes are calculated. Next, experiments are carried out using a vehicle with a four jack shaker rig to validate the analytical values of potential power harvest. For the considered vehicle, maximum theoretical power values of 1.1kW, 0.88kW and 0.97kW are associated with the bounce, pitch and roll modes, respectively, at 20 Hz excitation frequency and peak to peak displacement amplitude of 5 mm at each wheel, as applied by the shaker. The corresponding experimentally power values are 0.98kW, 0.74kW and 0.78kW. An experimental rig is also developed to study the behavior of regenerative actuators in generating electrical power from kinetic energy. This rig represents a quarter-vehicle suspension model where the viscous damper in the shock absorber system is replaced by a regenerative system. The rig is able to demonstrate the actual electrical power that can be harvested using a regenerative system. The concept of self-powered actuation using the harvested energy from suspension is discussed with regard to applications of self-powered vibration control. The effect of suspension energy regeneration on ride comfort and road handling is presented in conjunction with energy harvesting associated with random road excitations.Peer reviewedFinal Accepted Versio

Bridge expansion joint in road transition curve: effects assessment on heavy vehicles

Properly-designed road surfaces provide a durable surface on which traffic can pass smoothly and safely. In fact, the main causes that determine the structural decay of the pavement and its parts are the traffic loads. These repeated actions can create undesirable unevennesses on the road surface, which induce vertical accelerations on vehicles, up to hindering contact between pavement and tire, with dangerous consequences on traffic safety. The dynamic actions transmitted by the vehicles depend on these irregularities: often, a bridge expansion joint (BEJ), introducing a necessary discontinuity between different materials, determines from the beginning a geometric irregularity in the running surface. Besides, some structural conditions could emphasize the problem (e.g., local cracking due to the settlement of the subgrade near the abutment or the discontinuity of stiffness due to the presence of different materials). When the BEJ is located in a transition curve, an inevitable vertical irregularity between road and joint can reach values of some centimeters, with serious consequences for the road safety. This paper deals with the analysis of a case study of a BEJ. Several test surveys were performed in order to fully characterize the effects on both vehicles and pavement. The three-dimensional representation of the pavement surface and the acceleration measurements on a heavy test vehicle were performed to analyze the joint behavior under traffic. Finally, a finite element model was implemented to evaluate the stress contribution on vehicle components induced by the vertical irregularities

Track train dynamics analysis and test program: Methodology development for the derailment safety analysis of six-axle locomotives

The operational safety of six axle locomotives is analyzed. A locomotive model with corresponding data on suspension characteristics, a method of track defect characterization, and a method of characterizing operational safety are used. A user oriented software package was developed as part of the methodology and was used to study the effect (on operational safety) of various locomotive parameters and operational conditions such as speed, tractive effort, and track curvature. The operational safety of three different locomotive designs was investigated

Racing car chassis

Cílem této bakalářské práce je analýza současných konceptů podvozků závodních okruhových aut. V první části práce je zpracován historický vývoj, charakteristika kol a pneumatik s reprezentací dobře známých produktů. V druhé části je popsán systém odpružení, pružné média a tlumící členy. Systémy odpružení je zde rozdělen na nezávisle a polozávislé zavěšení kol a odpružení pevných náprav. Následující oddíl této práce je zaměřený na standardní kontrolní systémy, jako jsou ABS, ESC a TSC. Závěr přináší rychlé shrnutí této problematiky.The aim of this bachelor thesis is to analyse contemporary concepts of circuit race car chassis. In the first part of the thesis, the historical evolution is described and then wheels and tires characteristic within some well-known brand products are represented. The second important part includes the suspension systems, springing medium and damping members. The suspension systems are further divided to independent and semi-independent solutions and rigid axle suspensions. The end of this thesis deals with the standard braking control systems, such as ABS, ESC and TCS. The conclusion brings the quick summary of this subject.

Vehicle Dynamics, Lateral Forces, Roll Angle, Tire Wear and Road Profile States Estimation - A Review

Estimation of vehicle dynamics, tire wear, and road profile are indispensable prefaces in the development of automobile manufacturing due to the growing demands for vehicle safety, stability, and intelligent control, economic and environmental protection. Thus, vehicle state estimation approaches have captured the great interest of researchers because of the intricacy of vehicle dynamics and stability control systems. Over the last few decades, great enhancement has been accomplished in the theory and experiments for the development of these estimation states. This article provides a comprehensive review of recent advances in vehicle dynamics, tire wear, and road profile estimations. Most relevant and significant models have been reviewed in relation to the vehicle dynamics, roll angle, tire wear, and road profile states. Finally, some suggestions have been pointed out for enhancing the performance of the vehicle dynamics models

Study of an attitude reference system utilizing an electrically suspended gyro final report, 1 aug. 1964 - 31 mar. 1965

Miniature electrically suspended gyroscope for spacecraft attitude reference syste

Combined bounce, pitch, and roll dynamics of vehicles negotiating single speed bump events

This paper investigates vehicle dynamic response for the increasingly common manoeuvre over single speed bumps, which is a non-trivial complex motion. One major aim of the study is to investigate the effect of the anti-roll bar upon vehicle body dynamics, while negotiating such traffic calming features. Numerical predictions are made with an intermediate vehicle model, whose results conform well to the actual vehicle tests. These results seem to suggest that events caused by truncated speed bumps can have implications for design of anti-roll bars from a ride comfort viewpoint, over and above the usual requirements dictated by safe vehicle handling

New insights from fractional order skyhook damping control for railway vehicles

Active suspensions for railway vehicles have been a topic of research for a number of decades and while their applications in service operation are limited it seems clear that they will in due course see widespread adoption. Railway suspension design is a problem of compromise on the non-trivial trade-off of ride quality vs track following (guidance), and the skyhook damping control approach has been paramount in illustrating the potential benefits. Since skyhook damping control, various advanced control studies appeared contributing to redefine the boundaries of the aforementioned trade-off. Yet there is no study on the impact of fractional order methods in the context of skyhook railway active suspensions, and in particular related to skyhook damping control. This is the area to which this paper strongly contributes. We present findings from a current project on fractional order controllers for railway vehicles active suspensions, in particular work on the effect of fractional order methods in basic skyhook damping control schemes, i.e. pure and intuitively-based skyhook. Firstly we present a brief review of conventional skyhook damping control and then proceed to a rigorous investigation of the impact of fractional order on the ride quality / track following trade-off. The relevant benefits from fractional order methods are appraised and new insights highlighted