This paper reports the improved load-bearing structure of a hopper car for transporting pellets and hot sinter. In order to increase the strength of the load-bearing structure of a hopper car under the influence of high temperatures from the transported cargo, the use of cladding made of composite material has been proposed. This solution also contributes to a 5 % reduction in the wagon's tare compared to the prototype car. The dynamic load on the load-bearing structure of a hopper car was determined. This study was carried out for the case where an empty wagon was moving over an irregularity between the rail joints. The calculations showed that the studied dynamics indicators did not exceed the permissible values. At the same time, the ride of a hopper car is rated as "excellent". The main indicators of the strength of the carrying structure of a hopper car were determined taking into consideration the proposed improvement. That took into account the temperature effect exerted on the load-bearing structure of a hopper car by hot sinter. It was established that the maximum equivalent stresses occur in the zone of interaction of the girder beam with the pivot beam and are about 290 MPa. At the same time, stresses in the cladding of a hopper car are about 200 MPa, which is 12 % lower than those in a regular structure. Modal analysis was carried out to determine the frequencies and shapes of the natural oscillations of the bearing structure of a hopper car with a composite cladding. The calculation results demonstrated that the first natural frequency exceeds 8 Hz. Therefore, the safety of the wagon is provided. The coefficient of fatigue resistance of the load-bearing structure of a hopper car was calculated. It was established that its value is almost twice as high as the permissible one. That is, the resistance to fatigue of the supporting structure is provided. The research reported here could contribute to ensuring the strength of the load-bearing structures of hopper cars, reducing the cost of maintenance, and increasing the efficiency of their operation.

Purpose. The work is aimed to investigate the loading of load-bearing structure with composite material roof. This will allow reducing the dead weight of the hopper car and will contribute to the possibility of increasing its carrying capacity. Methodology. Investigations were performed using the example of hoper car for grain transporting, model 19-6869, manufactured by Karpaty Experimental Mechanical Plant. It is important to say that the use of composite material reduces the roof weight by up to 40% in comparison with the metal design. That is why mathematical modeling of dynamic loading of the hopper car with composite roof was carried out. Differential equations were solved by Runge-Kutta method in MathCad software package. Initial conditions were assumed to be zero. During the calculations, the spring suspension parameters of the 18-100 bogie models were taken into account. The obtained results of calculations were used when determining the main indicators of the roof strength. The spatial model of the hopper car roof was created in SolidWorks software complex. Calculation was performed by the finite element method, which is implemented in the SolidWorks Simulation (CosmosWorks) software complex. When constructing the finite element model of the hopper car, the isoparametric tetrahedra were used. The optimum number of the model elements was determined by the grapho-analytical method. Findings. The basic indices of load-bearing structure dynamics of hopper car with composite roof were obtained. Acceleration of the body in the mass center was 5,0 m/s2. Coefficient of vertical dynamics is equal to 0.67. It was found that the maximum equivalent stresses in the roof for all the considered loading schemes do not exceed the admissible values, that is, the roof strength is ensured. Originality. The mathematical modeling of dynamic loading of the load-bearing structure of the hopper car with composite roof was carried out. The acceleration values as the components of dynamic loading acting on it during operation as well as vertical dynamics coefficient were determined. The strength indicators of the composite roof under the main operational loading modes have been found out. Practical value. The conducted research will contribute to the creation of guidelines for the design of innovative structures of the rolling stock, as well as increase the efficiency of its operation.

Purpose. To substantiate the improvement of the load-bearing element of the wagon-platform for the possibility of transporting bulk cargoes. Methodology. In order to be able to transport bulk cargo on the wagon-platform, it is proposed to install a composite boiler module on it. In order to determine the dynamic load of the improved load-bearing structure of the wagon-platform, mathematical modeling was performed. The mathematical model formed by professor Bohomaz H.I. was used. However, within the framework of the research this model was refined to determine the load of the wagon-platform of the proposed design. The solution of the system of differential equations is carried out in the MathCad software package. To do this, the mathematical model was reduced to the normal Cauchy form, and then integrated by the Runge-Kutta method. The obtained acceleration is taken into account when calculating the strength of the advanced load-bearing structure of the wagon-platform. The calculation is performed in the SolidWorks Simulation software package, which implements the finite element method. Also, within the research the modal analysis of a load-bearing structure of the wagon-platform is carried out. Findings. Based on the calculations, it is established that the acceleration acting on the load-bearing structure of the wagon-platform car is 0.38 g, i.e. it is within acceptable limits. The results of the calculation of the strength of the improved design of the wagon-platform showed that the maximum equivalent stresses occur in the area of interaction of the spine beam frame with the pivot and is about 340 MPa, the maximum displacement made 8.6 mm. That is, the obtained stresses do not exceed the yield strength of the structural material. The results of the modal analysis showed that the values of the natural frequencies of oscillations are within acceptable limits, because the first natural frequency has a value greater than 8 Hz. Originality. The scientific substantiation of improvement of a load-bearing structure of a universal wagon-platform to transportations of bulk cargoes is carried out. Practical value. The conducted research will promote increase in efficiency of operation of railway transport and creation of developments concerning planning of innovative designs of a rolling stock.

Purpose. Creation and substantiation of the measures for adopting the supporting structure of the multipurpose semi-car to carry cargoes that need weather protection. Methodology. For the adaptation of supporting constructions of semi-cars to carriage of cargoes that need weather protection, it was proposed to apply a removable roof manufactured from composites. As the application of a removable roof enlarges the volume of the container of the semi-car, the authors defined the load on its construction with the help of mathematical modeling. The authors see semi-car as a system which includes three components – a supporting construction having a roof with two carts. The Runge-Kutta method was used to calculate the main dynamic parameters of the semi-car. These defined dynamic parameters were accounted during calculation of the strength of the dismountable roof. Graphic spatial modeling of a semi-car with a dismountable roof was performed in the SolidWorks software kit. The calculation of solidity is implemented by the method of ultimate elements using the SolidWorks Simulation program kit. The original frequencies and forms of vibrations of the supporting construction of the semi-car are performed in this research. Findings. The outcomes of a mathematical model of the dynamic loading of the supporting construction of the semi-car having a dismountable roof set that the obtained dynamic parameters are not higher than the allowable values. The acceleration of the semi-car supporting construction in the gravity center made approximately 4.5 m/s2. The vertical dynamic ratio amounts to 0.53. The car motion is evaluated as “excellent”. It was found that when the vertical load acts on the dismountable roof, the maximum tension emerging inside is 173.2 MPa. When concentrated load affects the dismountable roof, the biggest tensions are focused on the zones of its attachment to the upper strapping of the casing, and makes 205.7 MPa. It can be seen from the modal analysis that the first original frequency of the semi-car casing is equal to 9.6 Hz, which is more than the allowable value – 8 Hz. Originality. Models for determining the loading of the supporting construction of the semi-car having a dismountable roof from composites within the general modes of loading operation are given in this study. Practical value. The study results allow expanding the applicability of semi-cars by adapting them to the carriage of cargoes, which need protection from weather effects and can increase the performance of railroad carriage.

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