ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wag... more ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wagons for coal transportation. Respecting the existing design of the wagon, the special solution of the rubber elastic element which was subsequently installed in suspension system is designed. The element is very easy to install in existing wagons, between the laminated spring buckle and underframe. The methodology of identifying the causes of unwanted fractures is focused on theoretical and experimental analysis of behavior of suspension system with and without rubber elastic elements. Subsequent installation of rubber elastic elements at about 400 wagons in thermal power plant “Nikola Tesla”, Obrenovac, Serbia, has prevented the very frequent fractures of laminated springs and cracks on the underframes. This has enormously reduced costs of maintenance of wagons and increased the efficiency of railway transportation of coal from mining basin to the thermal power plant.
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Mar 14, 2023
The topic of this paper is the usage of the algorithm of marine predator (MPA) in the optimizatio... more The topic of this paper is the usage of the algorithm of marine predator (MPA) in the optimization of the suspension of rail vehicles with coil springs. The aim is to reduce the mass of set of coil springs as the main parts of rail vehicles suspension. The optimized set of coil springs must satisfy the appropriate conditions related to the suspension characteristics, with the aim of achieving the required operation quality and running security of the observed rail vehicle. Starting from the bi-linear characteristic of rail vehicles suspension and the analytical description of its parameters, an optimization problem is formulated. It is composed of six optimization parameters, an objective function and 16 constraints (eight for each coil spring in the set). The developed approach is applied in two specific examples of suspension optimization of four-axled freight wagons, the first with axle load of 200 kN and the second with axle load of 225 kN. The optimization problem is resolved using MPA. The acquired results showed that the given optimization approach with MPA provide a significant mass decrease compared to conventional design method of rail vehicles suspension with coil springs. The mass decrease of one set of coil springs in both examples is about 15.5%. Given that each considered four-axled freight wagon has 16 sets of coil springs, the decrease of the total coil springs mass per wagon in both examples is more than 60 kg. Since certified rail vehicles are commonly produced in large series, the proposed approach can be very significant for increasing profitability in the rail vehicles industry.
International Journal of Heavy Vehicle Systems, 2018
Experimental testing of the impact of railway wagons has shown that same test conditions with dif... more Experimental testing of the impact of railway wagons has shown that same test conditions with different types of cargo obtained different results. A theoretical model established in this paper enables determination of energy that is lost during the impact and coefficient of restitution. If inappropriate cargo is used, then it is possible to register forces that are more than 50% less than the actual values. It is necessary to determine limit values of coefficient of restitution for every type of wagon and cargo. The results of this paper may be important for improving the international regulations relating to the experimental testing of wagons.
ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wag... more ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wagons for coal transportation. Respecting the existing design of the wagon, the special solution of the rubber elastic element which was subsequently installed in suspension system is designed. The element is very easy to install in existing wagons, between the laminated spring buckle and underframe. The methodology of identifying the causes of unwanted fractures is focused on theoretical and experimental analysis of behavior of suspension system with and without rubber elastic elements. Subsequent installation of rubber elastic elements at about 400 wagons in thermal power plant “Nikola Tesla”, Obrenovac, Serbia, has prevented the very frequent fractures of laminated springs and cracks on the underframes. This has enormously reduced costs of maintenance of wagons and increased the efficiency of railway transportation of coal from mining basin to the thermal power plant.
During the exploitation of railway vehicles, failures of elements of the suspension are very ofte... more During the exploitation of railway vehicles, failures of elements of the suspension are very often. The fractures on the components of suspension are especially characteristics for freight wagons operating in extreme loading conditions. This causes a decreasing of the efficiency of rail transport and very often can cause a derailments with huge material damage and human victims. The task of this paper is to explore the possibilities for improvement of suspension behaviour through subsequent installation of rubber-metal elements of simple design. The methodology is based on the identification of causes of failures through numerical and experimental analysis of suspension behaviour. These research is basis for design of simple solutions of rubber-metal elements which can be subsequently installed in suspension of wagons. In this paper the proposed methodology is applied on the freight wagons for coal transportation whose suspension is based on laminated springs. Subsequent installatio...
The task of this paper is identification of stresses in a homogeneous isotropic disc weakened wit... more The task of this paper is identification of stresses in a homogeneous isotropic disc weakened with an eccentric circular hole which is loaded by pressure in the internal contour of the hole. By application of a complex variable method, the mathematical model that allows complete analytical solution of stresses of the disc is formed. The methodology can be applied for the solution of any disc weakened with an eccentric circular hole. The comparative analysis has shown a high accuracy of analytically obtained results with FEM results obtained by calculations in ANSYS 12 software package. The application of the results of this paper is of great importance for quality design and optimization of thin-walled structures of disc type weakened by a circular hole.
Railway transport has a very important role in economy of every country. The efficiency of railwa... more Railway transport has a very important role in economy of every country. The efficiency of railway transport depends both on the quality of transport organization and on the technical reliability of the railway rolling stock. During operation of the railway freight wagons in the last years, a large number of breaks of suspension system elements have been noticed. This feature is especially reported at four-axle double wagon for coal transport (designated Fbd) and three-axle wagon for transport of cars (designated DDam). Frequent breaks of suspension system elements reduce the efficiency of transport and in some cases cause derailment of wagons and lead to large economic losses. In this paper, the causes of breakage of suspension on both wagons (Fbd and DDam) have been analyzed, but also the possibilities of how to resolve these problems, i.e. how to reduce them to a minimum or avoid them completely.
ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wag... more ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wagons for coal transportation. Respecting the existing design of the wagon, the special solution of the rubber elastic element which was subsequently installed in suspension system is designed. The element is very easy to install in existing wagons, between the laminated spring buckle and underframe. The methodology of identifying the causes of unwanted fractures is focused on theoretical and experimental analysis of behavior of suspension system with and without rubber elastic elements. Subsequent installation of rubber elastic elements at about 400 wagons in thermal power plant “Nikola Tesla”, Obrenovac, Serbia, has prevented the very frequent fractures of laminated springs and cracks on the underframes. This has enormously reduced costs of maintenance of wagons and increased the efficiency of railway transportation of coal from mining basin to the thermal power plant.
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Mar 14, 2023
The topic of this paper is the usage of the algorithm of marine predator (MPA) in the optimizatio... more The topic of this paper is the usage of the algorithm of marine predator (MPA) in the optimization of the suspension of rail vehicles with coil springs. The aim is to reduce the mass of set of coil springs as the main parts of rail vehicles suspension. The optimized set of coil springs must satisfy the appropriate conditions related to the suspension characteristics, with the aim of achieving the required operation quality and running security of the observed rail vehicle. Starting from the bi-linear characteristic of rail vehicles suspension and the analytical description of its parameters, an optimization problem is formulated. It is composed of six optimization parameters, an objective function and 16 constraints (eight for each coil spring in the set). The developed approach is applied in two specific examples of suspension optimization of four-axled freight wagons, the first with axle load of 200 kN and the second with axle load of 225 kN. The optimization problem is resolved using MPA. The acquired results showed that the given optimization approach with MPA provide a significant mass decrease compared to conventional design method of rail vehicles suspension with coil springs. The mass decrease of one set of coil springs in both examples is about 15.5%. Given that each considered four-axled freight wagon has 16 sets of coil springs, the decrease of the total coil springs mass per wagon in both examples is more than 60 kg. Since certified rail vehicles are commonly produced in large series, the proposed approach can be very significant for increasing profitability in the rail vehicles industry.
International Journal of Heavy Vehicle Systems, 2018
Experimental testing of the impact of railway wagons has shown that same test conditions with dif... more Experimental testing of the impact of railway wagons has shown that same test conditions with different types of cargo obtained different results. A theoretical model established in this paper enables determination of energy that is lost during the impact and coefficient of restitution. If inappropriate cargo is used, then it is possible to register forces that are more than 50% less than the actual values. It is necessary to determine limit values of coefficient of restitution for every type of wagon and cargo. The results of this paper may be important for improving the international regulations relating to the experimental testing of wagons.
ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wag... more ABSTRACT This paper presents the failure analysis and improvement of suspension system of Fbd wagons for coal transportation. Respecting the existing design of the wagon, the special solution of the rubber elastic element which was subsequently installed in suspension system is designed. The element is very easy to install in existing wagons, between the laminated spring buckle and underframe. The methodology of identifying the causes of unwanted fractures is focused on theoretical and experimental analysis of behavior of suspension system with and without rubber elastic elements. Subsequent installation of rubber elastic elements at about 400 wagons in thermal power plant “Nikola Tesla”, Obrenovac, Serbia, has prevented the very frequent fractures of laminated springs and cracks on the underframes. This has enormously reduced costs of maintenance of wagons and increased the efficiency of railway transportation of coal from mining basin to the thermal power plant.
During the exploitation of railway vehicles, failures of elements of the suspension are very ofte... more During the exploitation of railway vehicles, failures of elements of the suspension are very often. The fractures on the components of suspension are especially characteristics for freight wagons operating in extreme loading conditions. This causes a decreasing of the efficiency of rail transport and very often can cause a derailments with huge material damage and human victims. The task of this paper is to explore the possibilities for improvement of suspension behaviour through subsequent installation of rubber-metal elements of simple design. The methodology is based on the identification of causes of failures through numerical and experimental analysis of suspension behaviour. These research is basis for design of simple solutions of rubber-metal elements which can be subsequently installed in suspension of wagons. In this paper the proposed methodology is applied on the freight wagons for coal transportation whose suspension is based on laminated springs. Subsequent installatio...
The task of this paper is identification of stresses in a homogeneous isotropic disc weakened wit... more The task of this paper is identification of stresses in a homogeneous isotropic disc weakened with an eccentric circular hole which is loaded by pressure in the internal contour of the hole. By application of a complex variable method, the mathematical model that allows complete analytical solution of stresses of the disc is formed. The methodology can be applied for the solution of any disc weakened with an eccentric circular hole. The comparative analysis has shown a high accuracy of analytically obtained results with FEM results obtained by calculations in ANSYS 12 software package. The application of the results of this paper is of great importance for quality design and optimization of thin-walled structures of disc type weakened by a circular hole.
Railway transport has a very important role in economy of every country. The efficiency of railwa... more Railway transport has a very important role in economy of every country. The efficiency of railway transport depends both on the quality of transport organization and on the technical reliability of the railway rolling stock. During operation of the railway freight wagons in the last years, a large number of breaks of suspension system elements have been noticed. This feature is especially reported at four-axle double wagon for coal transport (designated Fbd) and three-axle wagon for transport of cars (designated DDam). Frequent breaks of suspension system elements reduce the efficiency of transport and in some cases cause derailment of wagons and lead to large economic losses. In this paper, the causes of breakage of suspension on both wagons (Fbd and DDam) have been analyzed, but also the possibilities of how to resolve these problems, i.e. how to reduce them to a minimum or avoid them completely.
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