26 research outputs found
Whether High Speed Railways shall be in Poland?
W 艣wiecie pojawi艂a si臋 tendencja do przywr贸cenia du偶ej roli transportu kolejowego g艂贸wnie w przewozach pasa偶erskich. Na taki stan sk艂ada si臋 kilka element贸w o charakterze ekonomicznym, spo艂ecznym i technicznym, kt贸re jednocze艣nie odpowiadaj膮 na pytanie: czy i dlaczego koleje du偶ych pr臋dko艣ci? Pierwszym elementem s膮 elementy funkcjonalne ekonomiczne. Na odleg艂o艣膰 do 1500 km przew贸z szybk膮 kolej膮; tak膮 o pr臋dko艣ci 350 km/h; jest konkurencyjny z innymi 艣rodkami komunikacji z samolotami w艂膮cznie. Nie wydaje si臋 koniecznym uzasadnia膰, 偶e koszty jednego pasa偶era na odleg艂o艣膰 1000 km s膮 ni偶sze ni偶 np. transportem lotniczym czy samochodowym. Przeprowadzone analizy w tym zakresie potwierdzaj膮 postawion膮 tez臋
Chosen problems of examination of car stability
This paper gives an overview on some chosen aspects of examination of car stability. It especially stresses the situation of an after repair car, with disturbances in its body geometry, mass, inertia and deviation. Such disturbances can occur especially after the side crash, which is one of the most common types of accidents
Selected aspects of analysis and modelling of a collision between two vehicles
W artykule przeprowadzono analiz臋 niekt贸rych aspekt贸w modelowania zderzenia samochod贸w z uwzgl臋dnieniem wybranych czynnik贸w wp艂ywaj膮cych na jego przebieg. Klasyczne podej艣cie do zderzenia cia艂 zaadaptowano do problemu kolizji samochod贸w, prowadz膮c og贸ln膮 analiz臋 z艂o偶ono艣ci tego zagadnienia. Pr贸cz uwzgl臋dnienia szorstko艣ci powierzchni zderzaj膮cych si臋 pojazd贸w rozwa偶ono tak偶e wyst臋powanie dodatkowych, zewn臋trznych si艂 impulsowych dzia艂aj膮cych na uk艂ad pojazd贸w b臋d膮cych w kontakcie. Ponadto, pr贸cz ruchu p艂askiego, uwzgl臋dniono tak偶e ruch z艂o偶ony (si艂a bezw艂adno艣ci, unoszenia i Coriolisa). Dokonano analizy dotycz膮cej mo偶liwo艣ci oraz konieczno艣ci uwzgl臋dnienia wybranych parametr贸w w modelowaniu zderze艅 samochod贸w.In the paper analysis of certain aspects of collision between motor vehicles modelling is presented including selected factors influencing its course. The classic approach towards the crash of mechanical bodies was adapted to the problem of the collision between vehicles, as the general analysis of complexity of this issue was conducted. Apart from taking the roughness of the surface of crashing vehicles into account, the occurrence of additional, external impulse forces acting on the set of vehicles being in contact was also assumed. Moreover, apart from the plane motion, also a resultant motion of each vehicle during the crash was included (forces of inertia and transportation as well as Coriolis force). Analysis was made concerning the possibility and necessity to take the selected parameters into account in modelling of collisions between vehicles
On a certain possibility of practical application of stochastic technical stability
Niniejszy artyku艂 prezentuje spojrzenie na definicj臋 stateczno艣ci technicznej stochastycznej (STS) oraz jej u偶ycie w symulacji zar贸wno modeli matematycznych wagon贸w kolejowych, jak i samochod贸w. Zaprezentowano u偶ycie STS w badaniu modelu matematycznego wagonu kolejowego w aspekcie jego stateczno艣ci poprzecznej. Przedstawiono r贸wnie偶 mo偶liwo艣ci wykorzystania stateczno艣ci technicznej stochastycznej w badaniu modelu matematycznego samochodu.This article gives an overview on the definition of stochastic technical stability (STS) and its use in simulation of railway car as well as motor car mathematical models. It presents how the STS was used to examine the mathematical model of railway car in aspects of its lateral stability. It also presents possibilities of using the STS to examine mathematical model of motor car
Selected examples of referring the examined stochastic technical stability to the ISO standards
In this paper, certain examples of comparison between the selected definition of the stochastic technical stability (for motor vehicle models) and the ISO definitions (developed for real vehicles) have been discussed. Being able to refer the examined stability of a mathematical model to the real object may result in verifying the properties of the latter on the basis of model tests, instead of the field trials. Such an attempt has been presented previously, but in a more general approach. The aim of this paper is to present a certain attempt to compare the results obtained for a simulated vehicle model in virtual environment with the specific definitions of stability dedicated to the real motor vehicles. The background of this considerations liesin the examination of the stochastic technical stability, which allows any mechanical system undergo external random disturbances, such as road irregularities
Analysis of the stochastic technical stability of engineering structures on an example of a moving car
The article presents analysis of the stochastic technical stability of mathematical models
(described by the second-order ordinary differential equations) of technical objects, on the
example of a moving motor vehicle with the disturbed location of the center of mass, as
a result of a non-uniform load. After conducting simulation of motion of a sport vehicle
mathematical model, using the MSC Adams/Car software, executing a maneuver of double
lane change without completely returning to the original road lane, interpretation of the
results in accordance with the given definition has been attempted. Specifically, the aspect
of determining the probability of the solution remaining in a certain area of feasible solutions
has been highlighted, as well as determination of the magnitude of this probability for stable
motion. In addition, attention has been paid to the selection of the upper limit of probability,
for which, under certain conditions, stable motion can be determined
Mathematical and simulation modelling of normal force for a rail
Description of dynamics occurring during the passage of a rail vehicle is a complex problem, and their mathematical relations are considered in several different aspects such as: interaction of normal force on a beam with fixed and variable cross-section, body, trolley and wheelset displacement and consideration of wheel-rail contact and other phenomena occurring in the contact surface, which include adhesion and creepage. The article presents the effects of work on the issues of normal force at the contact point of the wheel and rail. A mathematical model describing the dynamics of a rail vehicle was defined, determining the normal, transverse and longitudinal force appearing in the wheel-rail contact zone. Variations in the value of the normal force exerted by the wheelset on the rail are the quantity on which the parameters occurring in contact between the wheel and the rail depend. The obtained results from computer simulations show that the normal force is a variable parameter depending on the sign and magnitude of forces occurring between individual blocks of the rail vehicle during the movement. The results obtained will be used in further scientific work devoted to the contact problems
Chosen problems of road accidents analyses in Poland in the period between 1995 and 2004
W niniejszej pracy dokonano klasyfikacji zderze艅 samochod贸w ze wzgl臋du na statystycznie najcz臋艣ciej wyst臋puj膮ce wypadki oraz testy, jakim poddawane pojazdy s膮 nowo dopuszczane do sprzeda偶y. Niniejsza praca dotyczy rozwa偶a艅 na temat bezpiecze艅stwa ruchu drogowego w Polsce. Na jej 艂amach podj臋to pr贸b臋 analizy przebiegu i skutk贸w najpowszechniej wyst臋puj膮cych na drogach zderze艅. Wa偶nym jest problem stateczno艣ci jako elementu podlegaj膮cego zmianom w przypadku eksploatacji pojazd贸w powypadkowych. Problem ten jest przedmiotem oddzielnych bada艅. Kolejnym wa偶nym punktem jest przedstawienie danych statystycznych i pr贸b臋 analizy poziomu bezpiecze艅stwa na ich podstawie. Jako wa偶ny etap nale偶y postrzega膰 tu ch臋膰 por贸wnania niekt贸rych wska藕nik贸w w Polsce i we Francji, co pozwoli艂o na pr贸b臋 zweryfikowania niekt贸rych opinii o poziomie bezpiecze艅stwa ruchu na drogach w Polsce.This article offers classification of car collisions from the point of view of the most frequent accidents and crash tests. The most important problems are the consequences of incomplete control of a car which has been repaired after an accident. As a result, further use may lead to defective work of systems responsible for steering, driving comfort, and contact with the road surface as well as suspension. Firstly, the article focuses on the safety of road traffic in Poland and presents an attempt to analyze the course of most frequent collisions and their consequences. Stability is an important problem as it changes in a car driven after an accident, and should be analyzed in separate research. Secondly, it gives statistical data and attempts to analyze the level of road traffic safety. Some important indicators are shown here to compare the situation in France and Poland, which enabled verification of some opinions about the safety of road traffic in Poland
Test of quantity characteristic technical condition of railway turnouts
Ocena stanu technicznego rozjazdu kolejowego z uj臋cia bezpiecze艅stwa pasa偶er贸w podr贸偶uj膮cych poci膮giem odgrywa bardzo wo藕n膮 rol臋. Maj膮c na uwadze jak szybko ulegaj膮 zniszczeniu lub 艣cieralno艣ci materia艂y z kt贸rych wykonano zespo艂y wchodz膮ce w sk艂ad rozjazdu kolejnego, podj臋to pr贸b臋 okre艣lenia wykazu dopuszczanych odchy艂ek na segmentach rozjazdu kolejowego oraz wielko艣ci wyst臋puj膮ce w rozje藕dzie kolejowym a maj膮ce wp艂yw na dynamik臋 przejazdu pojazdu szynowego przez rozjazd. Obydwie grupy wielko艣ci charakteryzuj膮cych rozjazd mog膮 by膰 wykorzystane dla oceny stanu rozjazdu oraz zdefiniowania si艂 wyst臋puj膮cych przy przeje藕dzie przez rozjazd pojazdu szynowego. Przedstawiono r贸wnie偶 wyniki z analizy wykonanej dla rzeczywistych danych zawartych w formularzu technicznym rozjazdu kolejowego. Sformu艂owano r贸wnie偶 wnioski wysuni臋te z wykonanej analizy.The assessment of the technical condition of the railroad crossing from the approach to the safety of passengers traveling by train plays a very janitorial role. Bearing in mind how quickly destructive or abrasive materials of which the teams included in the next turnout were made, an attempt was made to determine the list of allowed deviations on railroad switch segments and values occurring at railway turnouts and affecting the dynamics of the rail vehicle passing through the crossroads. Both size groups that characterize the crossover can be used to assess the turnout status and define the forces occurring when crossing the crossover of a rail vehicle. The results of the analysis carried out for the actual data included in the technical train turnout form are also presented. Conclusions from the analysis were also formulated
Neural network in optimization of physical appearance in the training of railway vehicles by the rails
W artykule autorzy przedstawi膮 koncepcj臋 wykorzystania sieci neuronowej w analizie danych uzyskanych z proces贸w symulacyjnych przedstawiaj膮cych zjawiska fizyczne wyst臋puj膮ce w chwili przejazdu pojazdu szynowego przez tor. G艂贸wnymi parametrami na kt贸rych skupiono ca艂膮 uwag臋 s膮 wyst臋puj膮ce si艂y normalne, wzd艂u偶ne i poprzeczne w obszarze kontaktowym powstaj膮cym w skutek kontaktu ko艂a z szyn膮. Om贸wiono model matematyczny opisuj膮cy szereg zjawisk fizycznych zachodz膮cy pomi臋dzy poszczeg贸lnymi podzespo艂ami wchodz膮cymi w sk艂ad pojazdu szynowego. W dalszym ci膮gu artyku艂u po przedawnieniu w艂asnej koncepcji sieci neuronowej i wyja艣nieniu jej funkcjonowania om贸wiono algorytm, kt贸ry odpowiedzialny jest za eliminowanie warto艣ci si艂 odbiegaj膮cych znacz膮co od ustalonych warto艣ci. Wyniki z bada艅 symulacyjnych zaprezentowano w dw贸ch grupach, pierwsza odnosi si臋 do wykres贸w uzyskanych w trakcie przeprowadzenia bada艅 z wykorzystaniem oprogramowania Uniwersal Mechanism, w drugiej cz臋艣ci przedawniono wyniki z danych otrzymanych w pierwszym etapie test贸w przez sie膰 neuronow膮, Na zako艅czenie artyku艂u umieszczono wnioski wynikaj膮ce z zaprezentowanych w artykule bada艅.In the article, the authors present the concept of using neural network in analysis of data obtained from simulation processes presenting physical phenomena occurring at the moment of passing a rail vehicle through the track. The main parameters in which attention is drawn are the normal, longitudinal, transverse and vertical forces in the contact area resulting from the contact of the wheel with the rail. After a brief introduction, a mathematical model describing a number of physical phenomena occurring between the various components of the rail vehicle is discussed. In the article, after aging of the neural network's own concept and explanation of its functioning, an algorithm has been described, which is responsible for elimination of values of forces deviating significantly from optimal values. Results from simulation studies are presented in two groups. The first one refers to the graphs obtained during the study using the Uniwersal Mechanism software. In the second part the results of the data obtained in the first stage of the test were passed through the neural network. research article