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EN
This article presents a mathematical model of a planar system for the multipoint, oblique, and eccentric impact of rough bodies. The created model served for numerical investigations of the system’s behaviour. To analyse the influence of various parameters, three simplified cases were defined. Each of these cases focused on different aspects of the simulation. The first case was used to determine how many contacting bodies undergo impact at a given time point. This result was then compared with the experimental observations, which gave good agreement. The second case investigated the influence of the body configuration and the coefficient of friction (COF) on the sliding process during impact. Depending on the parameter values, the sliding process was divided into three main areas: slip-reversal slip, stick-slip, and continuous slip with increasing sliding velocity. The third case focused on the energy dissipation expressed by the coefficient of restitution (COR) and the angle of incidence of the initiating impact; this case showed possible improvement areas of the used impact force model.
PL
W artykule przedstawiono model matematyczny płaskiego zderzenia wielopunktowego. Konfiguracja zderzających się ciał pozwalała na wystąpienie zarówno zderzenia mimośrodowego jak i ukośnego oraz uwzględniała tarcie. Opracowany model posłużył następnie badaniom symulacyjnym. W celu przeanalizowania wpływu różnych parametrów na zachowanie systemu zdefiniowano trzy uproszczone przypadki. W pierwszym badano, jaka ilość ciał bierze jednocześnie udział w zderzeniu. Przeprowadzone porównanie otrzymanych wyników z obserwacjami eksperymentu pokazało dobrą zgodność. W drugim przypadku badano wpływ konfiguracji zderzających się ciał oraz współczynnika tarcia na przebieg procesu poślizgu w trakcie zderzenia. W zależności od wartości parametrów możliwe są trzy główne scenariusze: poślizg–zmiana kierunku poślizgu, poślizg–zatrzymanie poślizgu, ciągły poślizg ze wzrastającą prędkością poślizgu. Trzeci przypadek skupiał się na dyssypacji energii wyrażonej poprzez współczynnik restytucji oraz kierunku uderzenia inicjującego; przypadek ten pokazał obszary, w których wykorzystany model siły zderzenia wymaga dopracowania.
EN
The paper deals with issues connected with the behaviour of a streamer cable towed by a survey seismic vessel when the cable undergoes a strike triggered by collision with an underwater moving object. The consequences of such collisions may be both threat to the life of marine animals or damage to underwater units and large economic losses suffered by vessel owners. The risk of such collisions has increased over the last years as a result of increased offshore seismic survey operations. Therefore, a towed streamer should be very robust. To assure its robustness, we should know the deformation mechanism of a single streamer cable. This in turn requires the development of an appropriate mathematical model of such a phenomenon. In particular, the paper presents the characteristics of seismic survey vessels and streamers; an analysis of collisions that have occurred in the past; a statement of the problem, and a computer-aided system supporting simulation of the cable behaviour. To obtain all the necessary design parameters regarding the deformation mechanism of a streamer cable, we set up a dedicated computer-aided system that supports their calculation.
EN
The numerical approach for determination of influence of deformation of the gas bubble (radius 0.74 mm) on added mass coefficient in (i) steady-state conditions and (ii) during approach to the horizontal wall, is proposed. It is shown that the bubble deformation can be tuned numerically (within the range 1.06 - 1.88) via proper variations of the Laplace pressure, without changing the bubble radius. Influence of the bubble deformation on its motion parameters is discussed and compared to theoretical predictions regarding the bubble drag coefficient and Reynolds number. Moreover, the approach allowing determination of the added mass of rising bubble, on the basis of variations in fluid kinetic energy, is described. It is shown that calculated added mass variations strongly depends on the interplay between (i) the bubble deformation ratio and (ii) its rising velocity. This effect is especially important for added mass of a gas bubble approaching a solid wall, because it can affect the kinetics of drainage of the separating liquid film formed under dynamic conditions, when Re >> 1.
EN
This study aims to identify and quantify the economic benefits of eliminating collisions between two transport systems: rail and inland waterway transport. The collision between transport systems is caused here by the obsolete structure of a railway drawbridge, which constitutes an element of the railway line used by freight and passenger transport and is located on the main inland waterway used by inland waterways freight transport. Railway transport results in limitations of inland waterway transport and, vice versa, inland waterways transport blocks railway transport during lifting of the bridge span. In the case of railway transport, the low capacity of the single-track railway bridge constitutes an additional limitation of the development of transportation. There are plans to eliminate the collision in the regional transport system by constructing a new railway bridge in place of the old drawbridge. The effects of the transportation infrastructure improvement were measured directly for both rail and inland water freight systems as well as the result of the interaction between passenger rail and car and bus transport. In order to compare the different types of impact, the effects of different actions were valued in monetary terms. The planned intervention, as investigated here, will lead to reductions in the cost of time of inland waterways freight transport and costs of time of rail passenger and freight transport and a decrease in the external costs of transport. This will make possible transportation services that are both cheaper and more reliable.
EN
Road accidents and collisions are very common in Poland and, although for the last several years their number has been constantly decreasing, it is still one of the highest in Europe. This article attempts to provide an answer to the question whether drivers’ overrating the changes in the Polish road transport infrastructure might contribute to the status quo – the factor that has so far been left uninvestigated. In [21] the authors demonstrate that drivers take notice of the changes and perceive them as changes for the better.
EN
This paper demonstrates kinematic analysis of multiple trailers on a tractor system for production logistics. The analysis concerned three different steering systems of the trailers: virtual clutch and drawbar system, conventional clutch and drawbar system, double Ackermann steering system. Designed kinematic models contain various variants of paths: turning at a constant value of the steering angle, changing the steering angle as a result of an approaching collision. Each of these variants also included driving in a straight line after a 90° turn. The validation of the developed kinematic model was done by using a real logistic train, which path was registered via aerial drone. For each of the developed kinematic models, a visualization of drive through the 90° turn was created.
EN
Vehicle speeds have increased due to improved road condition. However, this increased speed can result in high energy collisions. Recently, a vehicle occupant in South Korea was killed by a fragment ejected from a concrete median barrier that was struck by a vehicle. The current design impact level of a concrete median barrier (CMB) is SB5-B (270 kJ). However, the impact level of the mentioned accident was estimated as over SB7 (2300 kJ). In the present work, a series of numerical analyses was conducted to reduce the fragmentations of CMB due to impact. Field test were utilized to verify the newly developed model of CMB in impact events. The wire-mesh reinforcements and increment of the cross section were considered as design modifications. In particular, a special device to absorb a significant collision energy has been developed without a dramatic increase in construction cost. This device consists of an empty space around the dowel bars which fix the barrier to the foundation. The empty space allows the dowel bars to deform to absorb collision energy. The performance of the new concrete median barrier equipped with the shock absorbing devices was verified by using carefully designed field test data.
8
Content available The impact of bird strikes on air transport safety
EN
The author will discuss the bird strike phenomenon and its impact on the air transport of passengers. In addition to the above, examples of flying accidents mainly caused by bird strikes will be provided. Furthermore, the issue of responsibility for accidents caused by bird strikes will be discussed, alongside legal regulations pertaining to subjects connected with the topic.
PL
W artykule przeprowadzono analizę porównawczą podejścia symultanicznego i sekwencyjnego wykorzystywanego w modelowaniu zjawiska zderzenia w układach wielobryłowych. Zaproponowano układ, na podstawie którego przeprowadzona została analiza. Metodę symultaniczną oraz sekwencyjną wykorzystano do wyznaczenia prędkości ciał układu po zderzeniu. Rezultaty te odniesiono do wyników otrzymanych z symulacji zaimplementowanej na podstawie stworzonego modelu w dziedzinie czasu. Przedstawiono otrzymane wartości liczbowe dla przykładowego zestawu parametrów. Na podstawie rezultatów przeprowadzonych badań symulacyjnych wyciągnięto wnioski.
EN
In the article a comparative analysis of sequential and simultaneous approach in collision modeling has been conducted. The analysis has been based on a proposed system. A simultaneous and sequential approach has been used to calculate velocities of the bodies after collision. Those results has been compared with the results obtained from a simulation implemented basing on a model created in a time domain. The results obtained for an exemplary set of parameters have been given. Basing on the conducted simulations a summary has been made.
PL
artykule przedstawiono analizę poziomu bezpieczeństwa ruchu drogowego w Polsce. Zaproponowano także sposób jego poprawy. Mieszkańcy Polski są przyzwyczajeni do otrzymywania wielu informacji medialnych na temat wypadków i kolizji drogowych. Dane statystyczne, zbierane i analizowane między innymi w ramach Polskiego Obserwatorium Bezpieczeństwa Ruchu Drogowego, funkcjonującego w strukturze Instytutu Transportu Samochodowego, są źródłem informacji służących podejmowaniu decyzji w zakresie działań na rzecz poprawy bezpieczeństwa ruchu drogowego. Przedstawione informacje odnoszą się do sytuacji na drogach we wszystkich regionach kraju. W artykule zaprezentowano ponadto możliwość zastosowania nowoczesnej technologii RFID, jako narzędzia wspomagającego działania dla potrzeb podniesienia poziomu bezpieczeństwa na drogach.
EN
The article presents analysis of the road safety level in Poland. A way to improve it was also proposed. The inhabitants of Poland are used to receiving a lot of media information about road accidents and collisions. A statistical data, collected and analyzed, among the others, by the Polish Road Traffic Safety Observatory operating in the structure of the Motor Transport Institute, is a source of information for decision making in the field of actions to improve road safety. The essential information refers to the situation on the roads in all regions of the country. The article also presents the possibility of using modern RFID technology as a supportive tool for the needs of increasing the road safety level.
EN
Article presents the applications designed to perform automatic communication as a support for navigators steering their ships. Authors took into consideration the conversation between navigators in the collision situation that occurred at North Sea basin. The performed incorrect communication has been presented and alternative to it has been proposed. The results of simulation made with use of the prototype of automatic communication and negotiation system has been shown.
PL
W artykule zaprezentowano aplikację utworzoną z zamiarem realizacji automatycznej konwersacji dla wspomagania nawigatorów kierujących statkami. Autorzy uwzględnili rozmowę między nawigatorami w sytuacji kolizji, która zdarzyła się na Morzu Północnym. Zaprezentowano niepoprawną komunikację pomiędzy statkami a także propozycję alternatywnej. Przedstawiono też wynik zasymulowanej komunikacji wykonanej z użyciem prototypu systemu automatycznej komunikacji i negocjacji.
EN
Oil spills from maritime activities can lead to very extensive damage to the marine environment and disrupt maritime ecosystem services. Shipping is an important activity in the Northern Baltic Sea, and with the complex and dynamic ice conditions present in this sea area, navigational accidents occur rather frequently. Recent risk analysis results indicate those oil spills are particularly likely in the event of collisions. In Finnish sea areas, the current wintertime response preparedness is designed to a level of 5000 tonnes of oil, whereas a state-of-the-art risk analysis conservatively estimates that spills up to 15000 tonnes are possible. Hence, there is a need to more accurately estimate oil spill scenarios in the Northern Baltic Sea, to assist the relevant authorities in planning the response fleet organization and its operations. An issue that has not received prior consideration in maritime waterway oil spill analysis is the dynamics of the oil outflow, i.e. how the oil outflow extent depends on time. Hence, this paper focuses on time-dependent oil spill scenarios from collision accidents possibly occurring to tankers operating in the Northern Baltic Sea. To estimate these, a Bayesian Network model is developed, integrating information about designs of typical tankers operating in this area, information about possible damage scenarios in collision accidents, and a state-of-the-art time-domain oil outflow model. The resulting model efficiently provides information about the possible amounts of oil spilled in the sea in different periods of time, thus contributing to enhanced oil spill risk assessment and response preparedness planning.
EN
Various methods of trajectory determination are used for finding solutions to collision situations involving ships. This applies to avoiding collisions with other ships or stationary objects. In addition to the methods generally used, new or modified versions of methods derived from other modes of transport are proposed. One of the algorithms for route determination serving to avoid obstructions is the method of artificial potential fields, used for determining routes of mobile robots. The method is used in maritime transport, for instance for detecting anomalies in ship movement. The article presents the method of potential fields used for solving the problem of route selection avoiding navigational dangers and obstacles. This article presents an algorithm of route determination based on the said method, its implementation in the MATLAB program and examples of application for the ship’s safe trajectory determination in some navigational situations.
PL
W referacie przedstawiono i uzasadniono możliwości wprowadzenia systemów aktywnego bezpieczeństwa do sterowania maszyn roboczych wzorowanych na odpowiednikach z dziedziny motoryzacji. Ukazano założenia dla systemu oraz wyniki symulacji zachowania zespołu roboczego według scenariusza sytuacji niebezpiecznej.
EN
Active safety systems in automotive reduced number of collisions and property damage. Advanced Driver Assistance Systems has proved effectiveness. It is possible to use similar systems to increase safety on construction site. Author shows a possibility of virtual simulations of common behavior of machines, with such a systems during movement on construction site. Sample scenarios has been presented in the paper.
EN
Bubble-particle interactions play an important role in flotation. This study examines the behaviour of bubble clusters in a turbulent flotation cell. Particularly, the bubble-particle interaction characteristics in flotation are investigated. The bubble size in a flotation column was measured using an Olympus i-SPEED 3 high-speed camera. Relationships between the circulating volume, bubble size and bubble terminal velocity were discussed. Probabilities of collision, attachment, detachment and acquisition between bubbles and particles in different circulating volumes were calculated based on the flotation kinetic theory. Using the extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theory, the relationship between the potential energy and distance in bubble-particle interaction was analysed. The results demonstrated that as the circulating volume increased, the bubble size and velocity decreased. When the circulating volume increased from 0.253 to 0.495 m3/h, the bubble diameter decreased from 511 to 462 μm, and the corresponding bubble velocity decreased from 43.1 to 37.5 mm/s. When the circulating volume remained constant as the particle size increased, probabilities of collision, attachment, detachment and acquisition increased. When the particle size remained constant as the circulating volume increased, these probabilities also increased. At a constant circulating volume as the particle size increased, the absolute value of the total potential energy between the particle and bubble increased. When the distance between the bubble and particle was 30 nm, the energy barrier appeared.
PL
Tematyka publikacji dotyczy analizy przebiegu zmienności opóźnienia pojazdu w czasie, w trakcie kolizji czołowej, w jego początkowej fazie. Zostanie dokonana aproksymacja liniowa współrzędnych funkcji przebiegu opóźnienia, jaka jest rejestrowana przez moduł ACU systemu SRS, w pierwszych chwilach kolizji pojazdu. W rozważaniach zostaną wzięte pod uwagę różne przebiegi kolizji czołowej.
EN
The subject of the publication relates to the analysis of the delay variation at the time the vehicle during a frontal collision in the initial phase. Will be made linear approximation function coordinates the course of delay, which is recorded by the module ACU of system SRS in vehicle collision. The discussion will take into account the different runs frontal collision
PL
W artykule omówiono wybrane zagadnienia prawa drogowego w krajach: Polska, Wielka Brytania, Niemcy, Węgry. Przedstawiono obowiązujące w każdym w tych państw definicje wypadku drogowego, a w Polsce również kolizji drogowej. Dokonano porównań: dopuszczalnego poziomu alkoholu we krwi kierowcy, dopuszczalnych prędkości na wybranych drogach. Porównano definicje wypadku drogowego i podziału wypadków drogowych ze względu na stopień ich ciężkości.
EN
The article discusses selected issues of traffic law in the following countries: Poland, United Kingdom, Germany and Hungary. It was presented the definition of a traffic accident in force in each of these countries, and also collision in Poland. Comparisons were made: the permissible level of alcohol in the driver's blood, the permissible speed on chosen roads. It compared definitions of a traffic accident and the division of traffic accidents due to the degree of their importance.
EN
The paper presents a concept of the new algorithm solving Last Moment Manoeuvre problem. Last Moment Manoeuvre means that action taken only by one vessel is not enough to avoid collision. This is why both vessels have to synchronize their manoeuvres to pass each other. The main focus of the proposed solution is concentrated on the procedure defining the best possible manoeuvre for each vessel when avoiding a collision is no longer possible. For simplification, the assumption that the parameters of the vessels involved in the Last Moment Manoeuvre meet Standards for Ships Manoeuvrability set out in the IMO resolution, will be adopted. The algorithm presented in the paper will be implemented and tested in the commercial system.
PL
W artykule przedstawiono nowy algorytm rozwiązania, tzw. manewru ostatniej chwili. Pod tym pojęciem autorzy rozumieją manewr, gdy działania podjęte przez tylko jeden statek nie zapewnią uniknięcia kolizji. Dlatego oba statki muszą zsynchronizować swoje manewry, by minąć się bezpiecznie. Istota zaproponowanego rozwiązania sprowadza się do procedury definiującej optymalny manewr dla każdego statku, zapewniając jednocze-śnie zapobieżenie kolizji. Dla uproszczenia przyjęto założenie, że jednostki spełniają standardy dla sterowności statków ustanowione w rezolucji IMO. Zaproponowany algorytm będzie implementowany i przetestowany w systemie oferowanym komercyjnie.
EN
Although in recent years the number of traffic accidents and collisions on Polish roads has been decreasing, it is important to identify their most significant causes. This study presents an analysis of 34 causes of road incidents reported by the police in the Wielkopolskie province in the years 2011-2013. A total of 34 causes of traffic incidents (accidents and collisions – X1, ..., X34, respectively) were grouped by means of hierarchic cluster analysis using the nearest neighbour method with Euclidean distances, in a four-dimensional space of parameters (the number of accidents - LW, the number of killed - LZ, the number of casualties, including slightly injured in collisions – LR, the number of collisions - LK). Calculations were conducted using the Statistica ver. 12 package. Analyses showed that the most common cause of traffic incidents included side collisions and rear collisions of vehicles, failure to yield to the right-of-way, failure to adjust the speed to the traffic conditions and failure to keep adequate distance between vehicles. Hitting a tree was only the 19th cause (out of 34 analysed ones); however, consequences of these incidents were tragic (8% of fatal accidents).
PL
W artykule dokonano ogólnej analizy miast pod kątem ruchu drogowego w Polsce. W oparciu o międzynarodowe oraz krajowe akty normatywne i prawne poddano analizie dane dotyczące wypadków i kolizji drogowych w Polsce z wyszczególnieniem pojazdów uprzywilejowanych.
EN
The article made a general analysis of cities in terms of traffic in Poland. Based on international and national normative acts and legal analyzed data on road accidents and collisions in Poland detailing emergency vehicles.
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