The work is devoted to the development of a method for neural network approximation of helicopter turboshaft engine parameters, which is the basis for researching engine energy characteristics to improve efficiency, reliability, and flight safety. It is proposed to use a three-layer direct propagation neural network with linear neurons in the output layer for training in which the scale conjugate gradient algorithm is modified by introducing a moment coefficient into the analytical expression. This modification helps in calculating new model parameters to avoid falling into a local minimum. The dependence of the energy released during helicopter turboshaft engine compressor rotation on the gas-generator rotor r.p.m. was obtained. This enables the determination of the optimal gas-generator rotor r.p.m. region for a specific type of helicopter turboshaft engine. The optimal ratio of energy consumption and compressor operating efficiency is achieved, thereby ensuring helicopter turboshaft engines’ optimal performance and reliability. Experimental data support the high efficiency of using a three-layer feed-forward neural network with linear neurons in the output layer, trained using a modified scale conjugate gradient algorithm, for approximating parameters of helicopter turboshaft engines compared to the analogues. Specifically, this method better predicts the relations between the energy release during compressor rotation and gas-generator rotor r.p.m. The efficiency coefficient of the proposed method was 0.994, which exceeded that of the closest analogue (0.914) by 1.09 times.
This article presents a mathematical model of the risk of failures, depending on the operating parameters, of locomotive diesel engines. The purpose of this study is to determine the risk of failures of locomotive diesel engines in maintenance. The theory of probability and the theory of logic and reliability are used in this theoretical study. The innovations and main works are the first approaches to calculating the risk of failures of locomotive diesel engines by hourly fuel consumption, which, under operational conditions, allows for extending the life of locomotive diesel engines during maintenance. As a result, a maintenance process for 5D49 diesel engines is developed in a locomotive depot. When managing the maintenance processes of 5D49 diesel engines in the locomotive depot, it is determined that the optimal mileage is 45,000 km. The resource of 5D49 diesel engines in the locomotive depot increased by 2.4% in the management of the maintenance process compared to the existing maintenance system.
1 December 2022 in Advances in Science and Technology Research Journal
The paper presents a new design of the gondola car hatch cover to increase the carrying capacity. The results of calculations the CAD model of the gondola car hatch cover showed that the maximum equivalent stresses do not exceed 216.4 MPa, the maximum equivalent displacements are 3.323 mm, and...
This paper presents an evaluation and reduction of energy consumption during railway train movement on a straight track section with reduced freight wagon mass. A theoretical model was developed to simulate energy consumption based on input parameters, including train speed, track gradient, section length, travel time, and train mass. The results indicate that energy consumption increases by 18.9% as speed rises to 90 km/h and as gradients increase to 2.0‰, while energy consumption decreases by 14.5% on a descending gradient of 1.5‰, which corresponds to the expected dynamics of railway trains. These results are supported by experiments showing that the MAPE error does not exceed 1.9%, which can confirm the accuracy of the developed model. A comprehensive analysis of the potential reduction in energy consumption with reduced freight wagon mass was also conducted. Using a freight wagon design with a reduced mass of 2.3% allows for a reduction in energy consumption by 8–89 kW·h, depending on the length of the section and the speed of movement.
Increasing the load capacity of freight wagon bodies is a key issue aimed at improving the energy efficiency and competitiveness of rail transport. This study presents for the first time a design for a freight wagon body with increased load capacity and proposes new changes to the design of the freight wagon floor. To verify the proposed solution, CAD models of the freight wagon floor with thicknesses ranging from 3 to 6 mm were developed, and calculations were performed for von Mises stresses, resultant displacements, equivalent strains, and safety factors for each model. The factor of safety of the freight wagon floor structure has been increased by 5.2 times. The results indicated that the load capacity of the freight wagon with the modified floor increased by 1.6% to 2.7%, depending on the thickness, compared to the baseline floor construction with a thickness of 7 mm. In addition to effectively increasing the freight wagon’s load, the proposed modifications maintain structural integrity and address mass considerations. Furthermore, these changes allow for the use of standard carbon steel, which provides additional economic benefits. The study confirms that the use of thinner materials in the floor construction can significantly enhance the overall performance of the freight wagon and operational efficiency in rail transport.
For the first time, a theoretical dependence was obtained to determine the filler concentration of the composite tape. On the basis of this dependence, a composite tape with variable mechanical and tribological properties can be obtained. It is proposed that the composite tape is welded onto the cylindrical surface of the central bowl of the rail truck bolster. The bench tests made it possible to determine the degree of wear of the central bowl of the rail truck bolster by means of a welded composite tape. The wear value of the central bowl of the rail truck bolster with welded-on composite tapes is 0.15–0.18 mm per 10,000 km of a freight car’s mileage. The predicted service life of the central bowl of the rail truck bolster with a welded-on composite tape is 320–420 thousand km.