MOST CITED
Update: 2021-07-01
Task „Implementation of procedures ensuring the originality of scientific papers published in the quarterly „Eksploatacja i Niezawodność – Maintenance and Reliability” financed under contract 532/P-DUN/2018 from the funds of the Minister of Science and Higher Education for science dissemination activities.
Emilian Szczepański
Wear of brake system components in various operating conditions of vehicle in the transport company
Efektywne zarządzanie flotą pojazdów związane jest z dbałością o ich racjonalne użytkowanie i właściwą diagnostyką. Wczesne wykrywanie potencjalnych nieprawidłowości pozwala zapobiegać awariom i realizować procesy transportowe w sposób niezakłócony. Jednym z ważniejszych podzespołów, z punktu widzenia bezpieczeństwa użytkowania pojazdu, jest układ hamulcowy. Na podstawie badań laboratoryjnych można wyznaczyć charakterystyki trwałości poszczególnych jego elementów. Najbardziej pożądane są indywidualne wskazania, odwołujące się do warunków eksploatacji. W niniejszym artykule, na przykładzie badań grupy pojazdów marki Renault, wyposażonych w tarczowe mechanizmy hamulcowe, przeprowadzonych w okresie dwóch lat, dokonano pomiarów zużycia elementów układu (tarcze i klocki hamulcowe) w funkcji wybranych czynników, zależnych od czasu i środowiska, w którym realizowane były przewozy. Do analizy wyników wykorzystano nieparametryczne testy statystyczne. Celem weryfikacji hipotezy o nieistotności różnic zastosowano testy Manna-Whitney’a, oraz Kruskala-Wallisa. Ich wyniki porównano z wynikami analizy wariancji ANOVA. Sprawdzono istotność czynników wpływających na stopień zużycia hamulców. Wskazano również możliwe kierunki wykorzystania wyników pomiaru zużycia hamulców do racjonalizacji procesów transportowych. Zaprezentowana metoda może znaleźć zastosowanie także do oceny innych elementów (zespołów, podzespołów, układów) pojazdów samochodowych.
Przebieg zużycia elementów układu hamulcowego w zróżnicowanych warunkach eksploatacji samochodu w przedsiębiorstwie transportowym
Effective fleet management is related to the care for their rational use and proper diagnostics. Early detection of potential irregularities enables to prevent failures and carry out transport processes in an undisturbed way. One of the most important components, from the safety point of view, is the braking system. Laboratory tests can be used to determine the durability characteristics of individual components. Individual indications referring to operating conditions would be most desirable. The article, based on a two-year period of testing of a group of Renault vehicles fitted with disc brakes, presents measurement of wearing and tearing the system components (brake discs and brake friction insert) in a function of selected factors, depending on the time and environment in which the transport was carried out. Nonparametric statistical tests were used to analyze the results. Mann-Whitney and Kruskal-Wallis tests were used to verify the hypothesis on the insignificance of differences. Their results were compared with the results of ANOVA variance analysis. The significance of factors influencing the degree of brakes wear was checked. Possible directions of using the results of brake wear measurement for rationalization of transport processes were also indicated. Presented method may also be applied to the evaluation of other components (assemblies, subassemblies, systems) of motor vehicles.
Risk assessment for rail freight transport operations
The aim of this article is to assess the risk of performance of rail freight transport on the basis of an analysis of identified risk areas based on statistical data on the causes of accidents that occurred on the lines of railway transport in Poland. A critical review of selected scientific studies relating to the risk assessment process for identified areas of the railway system has been undertaken. Based on statistical data, the authors analysed the causes of accidents on railway lines in 2019 in Poland and determined the probability of occurrence of a given cause. In addition, the article calculates the probability of vehicle delays for different emergency situations occurring in the performance of rail freight transport operations. This enabled the authors of the article to carry out a risk assessment of freight train delays on railway lines.
Selection of a fleet of vehicles for tasks based on the statistical characteristics of their operational parameters
The article presents a method of selecting a fleet of vehicles with a homogeneous structure for tasks based on the statistical characteristics of their operational parameters. The selection of a vehicle fleet for tasks is one of the stages of vehicle fleet management in transport companies. The selection of a vehicle fleet for tasks has been defined as the allocation of a vehicle model to a given company, which is associated with the unification of the vehicle fleet to one specific type. The problem of selecting a fleet of vehicles has been presented in a multi-criteria approach. The operational parameters assessing the selection of vehicles for the tasks are mileage and the number of days to the first and subsequent failure, and vehicle maintenance costs. The developed method of selecting a fleet of vehicles for the tasks consists of two stages. In the first stage, the average operating parameter values are determined using statistical inference. In the second stage, using the MAJA method, a unified model of the fleet of vehicles operating in the enterprise is established.
Intelligent mobility: A model for assessing the safety of children traveling to school on a school bus with the use of intelligent bus stops
The aim of the article is to develop a model for assessing the safety of children’s travel. Safety is the most important indicator describing the mobility system of children, even more important than the costs of operating it. Due to the dynamic development of intelligent solutions, it is possible to undertake additional activities supporting the improvement of children’s safety when traveling to and from school. However, their implementation requires an adequate assessment of a children’s mobility system. Currently, there are no solutions that could comprehensively support the decision-making process in this sphere. The article presents the issues of children’s mobility, a literature review in this area, mathematical model for assessing school bus travel, and a computational example. The presented approach is an original solution allowing for evaluation of the existing systems and their development scenarios. In addition, it enables the comparison of children mobility systems of different complexity and scale.