Applied Mechanics and Materials Vols. 809-810

Abstract: The aim of this paper is to analyze the reliability of freight wagon wheelset on the basis on real field data, observed and collected in actual operations of freight wagons. The failure modes and their associated occurrence absolute frequencies are identified and a Pareto analysis is carried out.The Weibull probability distribution is used to determine the reliability mathematical model for railway wheelset. The probability law is linearized, allowing the use of linear regression to estimate, on the basis of empirical data, the˰̸̵̱̓̀˰̵̵̱̱̀͂̽̈́͂˰ڂ˰̴̱̾˰̸̵̈́˰̵̳̱̼̓˰̵̵̱̱̀͂̽̈́͂˰ڇ of Weibull distribution. The estimated reliability model is close to an exponential one, assuming a failure rate almost constant.The estimated reliability probabilistic model i̓˰̴̵̴̱̼̹̱͆̈́˰̲͉˰̵̶̷̹̀͂̿͂̽̾˰̱˰ڗ² test to verify that the estimated theoretical reliability mathematical model fits the the empirical distribution.

Abstract: The study refers to optimizing energy consumption from electric trains, underground trains and electric locomotives. The actual requirements of the dynamic market economy are forcing the railway system to transform into a reliable alternative to the road and air traffic. From this perspective, the railways have to fulfill two key elements: Economical efficiency and reliability and to offer what the potential customer needs. One of the main elements is the respect of the timetables or (if possible) the decrease of the running times. The running time is the main referential, especially when it’s related to the power consumption. The optimization of the running times and the power consumption is the most important target for railway operators and depends on the correct choice of the drive regimes. Article deals with energy optimization from the perspective of traction. Analysis can be applied also to diesel railcars and diesel locomotives.

Abstract: Through the past years numerous theories regarding the contact between the wheel and the railway have been created with the purpose of resolving the interaction issues and improving the dynamical performances of the vehicle. In this context the paper comes with a three-dimensional approach of the contact between the wheel and the railway when there is a load transfer or a dual-contact. The analysis is done through the use of the CONTACT software which assimilates the contact the contact area through half-spaces and it divides it through the method the finite element [1]. In the contact area the linear elasticity theory is respected. CONTACT establishes the shape and size of the contact area between two elastically, deformable bodies found in tangential contact (normal loads). This thing is possible only if the form of the profiles found within the contact area is known. The analysis suggested through the paper validates the applicability of the CONTACT software for the profiles used by CFR and for the analysis of the dual-contact. Also, this approach allows the possibility for a tribological evaluation of the vehicle's behavior while traveling on a rail with excess as well with a rail with super-elevation deficiency.

Abstract: Gusts of wind with high speed can adversely affect the operation of the electric railway vehicles. These vehicles are able to move and to obtain a high performance, as long as the power supply is ensured. The variation of the vertical forces for maintaining contact between pantograph and catenary may cause interruption of the power supply of the electric railway traction vehicles. The placement of the capture equipment on the vehicle body determines appearance of aerodynamic forces acting on it. To see which are the vertical forces introduced by wind on active capture equipment, used at locomotives LE 060 EA of 5100 kW, we considered the EP3 type of pantograph as model. This was modelled at scale 1:1 taking into account the placement on the body of the locomotive. For the simulation of wind we considered three point values of its speed (10 m/s, 20 m/s, 30 m/s) and angle of eight values that are within the range of 0 deg – 180 deg. With the results of the simulation we have done a comparative analysis on the additional vertical forces introduced by wind for the cases analyzed.

Abstract: Power supply the energy needed for locomotives and electric trains is performed by means of pantographs on the bodywork. These high performance producing vehicles in so far as the contact between the collector (pantograph) and the catenary (contact line) is achieved and maintained regardless of speed. Thanks to the constructive type of the pantograph and the location of the contact force varies in relation to speed and can give rise to phenomena of oscillators that enhances the vertical movements of the wire feeder. As such the problem is essential for a good current collection is dynamic in nature. The most favorable way of current collection is achieved when between full and contact wire can maintain contact through a permanent and constant contact, a situation difficult to achieve in practice because of the first bump of the contact line. Juddering movements in vehicle while walking to a modification of the contact pressure which, however, it was found that is negligible in relation to the wave-like movements of the contact line. This article has looked at what is the dynamic contact force variation where the pantograph is located on the body of the locomotive EP3 LE 060 EA of 5100 kW. For this I started from the constructive characteristics of the components of the pantograph.

Abstract: This article presents the approach to the problem considered with optimizing the stress distribution and functioning of a crankshaft system of a piston engine. One of possible methods of investigating such a problem is simulation of work of the analyzed mechanical system. This approach allows observing the work of a modeled system and improving the designed system. In this work was applied the PLM Siemens NX software. This advanced CAD/CAE/CAM environment let to model any complex system of a technical mean. Using this environment it is possible to model and analyze new solution, which allow significantly optimizing the functioning conditions of a piston engine. One of such a solution is the MDI system presented in the work.

Abstract: The paper originally investigates the influence of the admitted ranges of slow-acting filling time of brake cylinder on longitudinal dynamics of freight trains, using experimental air pressure data obtained in tests on filling characteristics. Mechanical and pneumatic models are summarized and numerical simulations were performed for a train composed of six wagon train, in different filling characteristics configurations. The results reflect significant effects on in-train forces values, while evolution and disposition of compression and tensile forces between neighbored vehicles in the long of the train are also affected.

Abstract: With more than 4,000,000 units sold worldwide, Toyota Prius represent a successful story in the hybrid electric vehicles industry. The paper presents the economic and social context that led to the development of this new type of car and the evolution of Toyota Prius, which arrive now at the third generation. This spectacular achievement was the result of an impressive R&D effort that led to hundreds of new inventions and innovations. Some of them (engine cycle, battery, hybrid system etc.) are presented in this paper, with emphasis on truly revolutionary solutions for the automotive industry, which clearly distinguishes Toyota Prius from other hybrid vehicles. Besides the innovative character, these solutions offer better environmental and economic performance, but without compromising the well-known Toyota reliability. Toyota Hybrid System receives his confirmation by the prestigious organization TUV Germany, which ranks Toyota Prius first in reliability top in the recent years. We can thus say that besides the economic and ecological advantages Prius has made an important contribution to growth and strengthening Toyota brand, being a truly successful product.

Abstract: Thermal analysis of a DC motor cooling system and description of measurement system applied to an engine test stand are the main topics of the paper. The motor that is being tested comes from the electric vehicle of Silesian Greenpower project whose aim is to design and build energy efficient bolids in order to participate in international races in Great Britain. During the designing process of the car, minimizing energy losses and maximizing powertrain efficiency are the main aspects taken into consideration. One of the crucial issues to accomplish these goals is to maintain optimal performance of the motor by applying effective cooling. The engine test stand used in this research was designed especially for Silesian Greenpower vehicles. Thanks to its modular construction and versatility, it enables measuring many different parameters of the motor and powertrain. In this paper the thermal analysis is described as well as how the measuring system of the engine stand works. The thermal analysis described in the article occurred to be very helpful in improving the cooling system and motor performance in the same time. The advanced measuring and control system of the test stand enables conducting versatile analysis of the DC motor and the powertrain.

Abstract: In the case of electric railway vehicles of surface, the equipments which allow power supply are placed on their bodywork. The mode to dispose these equipments contributes to increase the resistance to motion of the vehicle due to the variation cross-section area. Gusts of wind that occurs during the movement of vehicles lead to increased aerodynamic forces. As a model analyzed, we considered the situation determined by the dispose of the equipments supply on the body of electric locomotive type LE 060 EA of 5100 kW, when such a vehicle is travelling with the first post station in the driving direction. The equipment’s components of supply were modeled geometric at scale 1: 1 in 3D. The obtained assembly was imported in an air flow simulation program to determine the aerodynamic resistances. To observe which is the influence of the gusts wind regarding the resistance to moving we considered five point values for wind speed: 5m / s, 10m / s, 15m / s, 20m / s and 25m / s. With results of the simulations we performed a comparative analysis.