Determination of Critical Speed of Rail Vehicle as Mechanical System with Nonlinear Constraints

The article considers approaches to the determination of the critical speed of the rail vehicle which is the minimal speed along the straight flat part of the way with constant vibrations of curved movement of rail vehicle having an autovibrational character. As a result of the analyses of the existing approaches to the evaluation of motion stability of a rail vehicle as a mechanical system with nonlinear constraints, the authors introduce an original method to determine the critical speed based on the results of imitational modeling of a freight car. The article contains theoretical approaches to the development of the method introduced, analyzes processing and appearance of autovibrations of curved movement of a rail vehicle, and introduces the developed method of evaluation of critical speed for a rail vehicle with imitational modeling of the movement of a freight car as a mechanical system with nonlinear constraints. The method described in the article allows making a preliminary evaluation of the critical speed value within the stage of rail vehicle design as well as evaluating the influence of some constructive parameters of a technical realization of rolling stock units within different stages of designing and in the process of a rail vehicle life history which allows cutting the economic expenses within the stage of freight car designing and traffic safety increasing.