Non-linear Dynamics Analysis of Absorption Process of Collision Kinetic Energy of Rail Vehicles using Finite Element Method

Development of passive safety elements presents very important activity directed in increase of safety in railway traffic. Basic role of passive safety elements is to absorb requested amount of collision kinetic energy through its own controlled deformation and to reduce the values of the force that is transferred to the rest parts of the vehicle structure. In this way it prevents deformation of the middle-passenger zone of the wagon and at the same time the number of human casualties and material damage is reduces to a minimum. Experimental investigations of the several types of absorbers showed that the absorber which works on the principle of shrinking the tube passing through special cone bush presents most acceptable solution from aspect of gradual increase of deformation resistance, possibility of fully control of deformation process and the amount of energy absorbed. Absorber developed in this paper consists of the seamless tube made by low carbon steel in quality P235T1 and the cone bush made by quench and tempered carbon steel in quality C45E. Quasi-static laboratory investigations of elements of absorber and dynamic investigations realized through collision of passenger coaches are the key part of experimental investigations and verification of prototype of absorber. Numerical model of the tube absorber was developed. Nonlinear numerical simulations of deformation process using finite elements method and strain rate dependent options were realized. Based on the results of experimental investigations the key parameters which verifies developed numerical model for use in further researches in field of quasi-static as well as dynamic environment (high deformation rate) were defined. During future investigations, developed numerical model can be used in process of dimensioning of elements of different absorption power, while for the final verification of prototype is necessary to perform dynamic test in accordance to valid standards – CRASH TEST

Analysis of impact the pressure on the rail vehicles and passenger during movement

The aim of this master's thesis is to provide a broader picture that refers to the impact of a sudden change in pressure during the movement of a rail vehicle on passengers, formwork and rail vehicle devices. The highest values of aerodynamic loads of the rail vehicle are achieved when entering and passing through the tunnel. When a train passes through a tunnel, pressure waves propagate along the tunnel at approximately the speed of sound. These pressure waves can penetrate inside the train if the vehicle is not adequately sealed and can cause discomfort to passengers on the train. To avoid negative effects, it is necessary to prevent a sudden change in pressure in the passenger compartment. Active protection means a closed circuit of the air conditioner where the ventilation is constantly on. On the other side, passive protection means closing the air conditioning system during the formation of shock waves, until a sudden change in pressure from the outside is overcome. With this closure, there is 100% air circulation inside the cabin, meaning there is no intake of fresh air. However, there is a problem with the accumulation of carbon dioxide in the cabin of the rail vehicle, over a long period of time overcoming the increase in pressure. The master's thesis deals with the occurrence and spread of pressure surges, the impact of pressure surges on the formwork of a rail vehicle and on a person. The results of the analysis show that the greatest influence on the pressure wave are cross-sections of the tunnel and the train, as well as the geometry of the tunnel portal and the vehicle speed itself. Based on the obtained results, it is possible to reduce the pressure by changing the geometry of the tunnel portal, as well as by increasing the cross-section of the tunnel, and by reducing the crosssection of the vehicle. Considering the respect of the dimensions of the vehicle, the first two options are resorted to. It is also possible to reduce the speed of the vehicle when entering the tunnel in order to reduce the pressure on the vehicle itself

Development and analysis of static strength of the pinafore flaps on the low-floor tram on avenio platform

The aim of the master thesis is weight optimization of the existing construction of the pinafore flaps and production cost reduction as much as possible. This was done by designing a new construction solution and applying of new material, and thus a new way of producing pinafore flaps that are implemented in the construction of low-floor trams of the "Avenio" platform. The "Avenio" platform is a tram model developed by Siemens mobility and it is in use all over the world, so depending on the needs of the customer can be offered different designs. The pinafore flaps are covering the running and the motor bogies, and it is a part of the vehicle body. The existing construction is based on aluminum, while for a new one is used GFRP. The 3D design of the new construction was performed by using CREO Parametric software package. The static strength analyses via the finite element method (FEA) of the existing and new construction were analyzed by using the ANSYS software package. Based on the previous it can be concluded that the new design with a lower mass can withstand normal exploitation load without permanent deformation

Experimental and numerical determination of tube collision energy absorbers characteristics

Razvoj apsorbera energije sudara je jedna od neophodnih mera pasivne zaštite putničkih vagona. Uloga pasivne zaštite je da posledice sudara svede na najmanju moguću meru. Apsorber razvijan u ovom radu sastoji se od čeličnih bešavnih cevi u kvalitetu P235T1 i konusne čaure napravljene od čelika za poboljšanje u kvalitetu C45E. Tokom sudara provlačenjem cevi kroz konusnu čauru dolazi do redukcije - smanjenja prečnika cevi pri čemu se troši energija. U radu su analizirani rezultati dobijeni numeričkim simulacijama i dinamičkim ispitivanjima cevnih apsorbera kinetičke energije sudara putničkih vagona. Glavni cilj rada je uspostavljanje korelacije rezultata dobijenih numeričkim simulacijama i eksperimentalnim istraživanjima. Korišćenjem karakterističnih parametara dobijenih tokom kvazi-statičkih, dinamičkih ispitivanja i numeričkih simulacija, definisane su vrednosti ključnih parametara koje se mogu koristiti za buduća ispitivanja cevnih apsorbera ovog tipa pri brzinama većim od 20 km/h. Numeričke simulacije se mogu koristiti u fazi razvoja apsorpcionih elemenata dok je za konačnu ocenu prototipa neophodno uraditi dinamička ispitivanja.Development of collision energy absorbers is one of the necessary measures for passive safety of passenger coaches. The purpose of passive safety is to minimize the collision consequences for passengers. The collision absorber developed in this work consisted of a low carbon seamless steel tube and conical bush fabricated from quench and tempered carbon steel. During collision, the seamless tube is compressed into a bush with a reduced diameter. In this paper, the analysis of results is obtained by numerical simulations and dynamic investigation of tube absorbers of kinetic collision energy of passenger coaches. The research focuses on correlations between numerical and dynamic test results. Using the characteristic parameters obtained by the dynamic tests and numerical simulations, values for key numerical parameters have been defined, which can be used for further investigations of tube shrinking absorber. Numerical simulations should be used in the developing phase of a prototype, while for the final verification it is necessary to do dynamic (impact) test

Design of windows of rolling stock for the passenger transport

The aim of the master thesis is the research the design and selection of the optimal glass for driver's cabin windows and passenger compartments, as well as their installation in the rail vehicle. The new windows should be designed and implemented in the "Avenio" trams. Choosing a new glass requires it to withstand normal operating loads, including environmental conditions, following EN 15152 and EN 50125-1 standard. In addition to selecting glass, it is necessary to choose the appropriate adhesive for mounting the window in the vehicle structure. In accordance with the Din 6701 standard, an analysis of the type and characteristics of the adhesive was described. The subject is to research and analyze the window load, as well as the thermal and acoustic characteristics of windows. Furthermore, the installation of windows in the vehicle structure and the design of windows for EMU (electric multiple units) were described

Analysis of construction and the connection of the table between vis-à-vis seats

The purpose of this research is to analyze and define requirements for the design of tables located between facing seats in passenger railcars. Tables between vis-à-vis seats are identified as a safety concern during passenger rail accidents because of the risk of serious thoracic and abdominal injury when passengers impact a table during an accident. Also, tables positioned between facing rows of passenger seats can serve to compartmentalize occupants during a collision, which can limit secondary impact velocity and prevent tertiary impacts with other objects or passengers. This paper contains an analysis of existing tables between vis-à-vis seats, including table geometry, table design, materials, flammability, table edge impact response, table attachment methods, crashworthiness testing, and fulfilling these requirements should result in reduced injuries and fatalities due to table impacts during passenger rail collisions. The main goal of this paper was to determine all the parameters directed to the design of this type of table and the way of its installation chosen, with reference to the existing ways of potential improvement and consideration of the standards, regulations, and rules must be applied

Geometry reconstruction and strength analysis of the door support for the metro train platform “inspiro”

Metro train platform “Inspiro” presents a base Siemens platform for all future metro systems that the company is going to produce. Platform "Inspiro" should have as many universal mechanical parts and elements as possible. The task of this work was to make a geometry reconstruction of the current construction solution, to ensure cheaper manufacturing of this door support. Different 3D models of the door support, using PTC software package, were constructed that should be manufactured by machining, welding, casting, and forging. To find the optimal solution, it was approached to strength analysis as well as techno-economic analysis. The stress and deformation analysis, and the calculation of the safety factor were performed by ANSYS software package. These analyses show how the door support behaves under the influence of a force of the weight of the door. Also, the aim of these analyses was to find optimal solutions, economically profitable to be able to consider the production and use of the most appropriate construction of door support. In this case, the casting method was chosen as the most profitable way to produce door support for this metro train system “Inspiro”

Implementation of 3d dimensioning through design of seat holder on “avenio” tram

The development of information technologies with a focus on digitalization allows further development of processes in all fields of mechanical engineering. Computer-aided design modeling is the base for designing Railway vehicles with additional potential to become used in all segments of vehicle lifecycle as a digital twin. These facts provide a guideline for moving to a new way of preparing documentation in 3D form instead of traditional 2D drawings. Because of that, the main subject of master thesis was to investigate the possibilities of preparing and designing documentation in a 3D environment. This thesis was made in cooperation between the Faculty of Mechanical Engineering in Belgrade and the company SIEMENS MOBILITY. All necessary Materials were made in programs that are used in the company working environment. 3D models were made in the program PTC CREO, and the program for presentation of the model with annotations JT2GO. Documentation was made according to ISO standard 16792 based on ASME 14.41 and internal company rules. Model for which documentation was made is a holder for driver seat in tram ”Avenio”. Finally, research was conducted with several suppliers in Serbia to assess whether there is the possibility of cooperation under these terms, as they are interested in investing and improving in this field and what were their comments. Conclusions were made with results of research and another older research done by ASME institute

Experimental research of the tube absorbers of kinetic energy during collision

Razvoj elemenata za apsorbciju energije sudara je sastavni deo pasivne zaštite putničkih vagona. Pasivna zaštita ima zadatak da posledice sudara svede na minimum. Apsorber prikazan u radu napravljen je od standardne bešavne cevi u kvalitetu P235T1 i konusnog prstena kvaliteta C45E. Predstavljeno rešenje se zasniva na korišćenju specijalnih elemenata koji apsorbuju određenu količinu kinetičke energije sudara putem kontrolisane plastične deformacije, čime se značajno smanjuje deo energije koji se prenosi na noseću strukturu vozila. Pri sudaru dolazi do sabijanja-provlačenja cevi kroz konusni prsten. Težište rada je na eksperimentalnim istraživanjima radi određivanja stvarnih karakteristika apsorbera ovog tipa. Na osnovu analize dobijenih rezultata ispitivanja, predloženo je konačno konstruktivno rešenje apsorbera, kao elementa buduće konstrukcije čeonog dela postolja vagona.Development of collision energy absorbing elements is a constituent part of passive protection of passenger coaches. The target of passive protection is to minimize the collision consequences. The absorber, described in this paper, is constructed from a standard seamless tube of the quality P235T1 and conical ring of the quality C45E. The solution presented is based on the application of special elements that absorb a certain amount of collision kinetic energy by means of controlled plastic deformation, significantly decreasing the part of the energy which is transferred to the vehicle bearing structure. The tube is compressed - pushed through the conical ring in collision. The paper focuses on the quasi-static and dynamics experimental research. Based on the analysis of the results obtained in the research, a final design of the absorber is suggested as a part of the future front part of vehicle bearing structure

Experimental and numerical determination of tube collision energy absorbers characteristics

Razvoj apsorbera energije sudara je jedna od neophodnih mera pasivne zaštite putničkih vagona. Uloga pasivne zaštite je da posledice sudara svede na najmanju moguću meru. Apsorber razvijan u ovom radu sastoji se od čeličnih bešavnih cevi u kvalitetu P235T1 i konusne čaure napravljene od čelika za poboljšanje u kvalitetu C45E. Tokom sudara provlačenjem cevi kroz konusnu čauru dolazi do redukcije - smanjenja prečnika cevi pri čemu se troši energija. U radu su analizirani rezultati dobijeni numeričkim simulacijama i dinamičkim ispitivanjima cevnih apsorbera kinetičke energije sudara putničkih vagona. Glavni cilj rada je uspostavljanje korelacije rezultata dobijenih numeričkim simulacijama i eksperimentalnim istraživanjima. Korišćenjem karakterističnih parametara dobijenih tokom kvazi-statičkih, dinamičkih ispitivanja i numeričkih simulacija, definisane su vrednosti ključnih parametara koje se mogu koristiti za buduća ispitivanja cevnih apsorbera ovog tipa pri brzinama većim od 20 km/h. Numeričke simulacije se mogu koristiti u fazi razvoja apsorpcionih elemenata dok je za konačnu ocenu prototipa neophodno uraditi dinamička ispitivanja.Development of collision energy absorbers is one of the necessary measures for passive safety of passenger coaches. The purpose of passive safety is to minimize the collision consequences for passengers. The collision absorber developed in this work consisted of a low carbon seamless steel tube and conical bush fabricated from quench and tempered carbon steel. During collision, the seamless tube is compressed into a bush with a reduced diameter. In this paper, the analysis of results is obtained by numerical simulations and dynamic investigation of tube absorbers of kinetic collision energy of passenger coaches. The research focuses on correlations between numerical and dynamic test results. Using the characteristic parameters obtained by the dynamic tests and numerical simulations, values for key numerical parameters have been defined, which can be used for further investigations of tube shrinking absorber. Numerical simulations should be used in the developing phase of a prototype, while for the final verification it is necessary to do dynamic (impact) test