Bahrov O. Damage reduction of the cast side frames of freight car bogies by structural and technological improvements

Dissertation is devoted to reduction of damage to the cast side frames of freight car bogies. A comprehensive approach to the assessment of the forces acting on the side frame of a freight car bogie on the curved track, which allows to carry out additional strength checks in the area of pedestal opening inner corner, as well as the theoretical underpinning of the axle box body side contact surfaces effect on the overhang of the freight car side frame while passing straight and curved track sections is offered. The proposed improved design of the side frame and axle box body can reduce the negative impact of twisting and bending moments at the pedestal opening inner corner and solve the problem associated with the kinked side frames of freight cars in operation. Finite element models are improved to characterize the strength of the freight car frame side, that will increase the accuracy of the determination of the local stress-strain state in hazardous areas of molded part by clarifying of the schemes for application of loads to the details, as well as the construction of computational models for the nominal size of the drawings followed by a rational partition of the obtained models into finite elements, depending on the features of a design of cast parts units. Theoretically, it confirmed the feasibility of the proposed technical solutions regarding the design of the freight car side frame and axle box body, which can reduce the effect of twisting and bending moments at the inner corner of pedestal opening while moving freight car on curved sections of track. Completed experimental research on friction surface hardening of freight car cast parts point at the feasibility of the surface plasma hardening method to increase the strength of the friction surfaces of freight car bogie cast parts. It proved the feasibility of the proposed technical decisions made on the basis of technical and economic analysis.