Study of Dynamic Indicators of Flat Wagon With Load Centre Shift

Abstract

Purpose. The article deals with the determining the influence of the longitudinal and lateral shift of gravity centre of the heavy load on the flat wagons, taking into account the travel speed based on the main dynamic indicatorsthe maximum coefficients of the dynamic supplement of spring-suspended and unsprung parts, the maximum ratio of frame force to static axle load, the wheel derailment safety factor. Methodology. The study was carried out using the method of mathematical and computer simulation of the dynamic loading of flat wagons based on the model of spatial oscillations of five coupled wagons and the software complex developed in the branch research laboratory of the rolling stock dynamics and strength (BRL RSDS). Theoretical studies were carried out during the movement of the model 13-401 flat wagon on typical 18-100 bogies with speeds in the range from 50 to 90 km/h in curves with radii of 350 and 600 m, with 130 and 120 mm canting, respectively. Findings. The paper presents the analysis of theoretical studies of the rolling stock dynamics on the example of flat wagons. The calculations were carried out using an application software package. In the course of performing theoretical studies and after simulation, taking into account the processes of oscillation of the flat wagon and load in the presence of longitudinal and lateral shift of its gravity centre, the dependences of the main dynamic indicators were obtained with regard to the magnitude of the travel speed. Originality. Using the mathematical model of the five coupled wagons, the effect of shift in two directions from the central symmetry axis of the heavy load centre was studied with regard to the travel speed along the curved track of small and medium radius in order to determine the dynamic loading of the flat wagon. Practical value. As a result of the above theoretical studies, the recommendations on the maximum possible values of the centre shift of heavy loads during their transportation on flat wagons are substantiated and proposed.

Research of Wheel-Rail Wear Due to Non-Symmetrical Loading of a Flat Car

“…In our research we studied the effect of the load mass center shift on the flat car frame in the longitudinal х А and transverse directions х А , as well as in both directions simultaneously. Preliminary theoretical studies have shown that in the presence of a transverse or simultaneous transverse and longitudinal displacement of the load mass center over 0.15 у А  m there is a sharp decrease in the derailment coefficient and a high probability of rolling stock derailment [21]. In order to determine the effect of only the load mass centre displacement on the factor of wheel and rail wear, the displacement in the transverse and simultaneous transverse and longitudinal directions is considered within the limits .…”

“…With these models, it is possible to obtain solutions for various types of wheel-rail contact, to take into account the rigidity of the structural elements and the various deviations from the initial configuration of the system, such as the misalignment of the wheel set axles in the bogie, the difference in the wheel radii of one wheel set, of different wheel sets in a bogie and different bogies, rail gradient and wheel profile of various types, change in the cross gap of the wheel set and rail track, the change of longitudinal and cross clearance between the axle-boxes and side frames, the displacement of the body mass center relative to the car symmetry, etc. [5,13,[17][18][19][20][21][22].…”

Dynamic indicators influencing design solution for modernization of the freight rolling stock

“…To reduce the forces transmitted to the wagon parts when moving along the curve, and the forces caused by changes in speed and body oscillations, it is necessary to reduce the center of mass of the wagon and reduce its displacement from the vertical symmetry axis. A decrease in the center of mass is also advisable for freight wagons with a relatively short bogie center distance [11][12][13][14]. In trains the longitudinal forces sometimes reach a value exceeding the strength of the frame of some wagon designs.…”

Effect of mass distribution on curving performance for a loaded wagon

“…For a further supplement to loading guidelines, the method of dynamics simulation has been used to search for the safe range of wagon's gravity center. Shatunov and Shvets [15] proposed that, as for a kind of 4-axle flat wagon, the maximum lateral offset could reach 150 mm and longitudinal offset could be expanded too. Bao et al [16] focused on a common open-top wagon in China and demonstrated that CR criteria were conservative.…”