Je.S. Oganjan, Dr. Sci. (Eng.), Chief Research Associate, vnikti15@yandex.ru G.M. Volohov, Dr. Sci. (Eng.), Department Head A.S. Gasjuk, Department Head D.M. Fazliahmetov, Lead Engineer E.V. Muravlev, Lead Engineer AO VNIKTI, Kolomna, Russia
As a result of the long work of the of the locomotive underframe structure (frame and body of the locomotive, their pivoted units, truck frames, wheelset axle, etc.) under the influence of sign-variable cyclic loads the following is occurred: accumulation of fatigue damages, degradation of strength properties of components metal. Also their fatigue resistance is decreased that can lead to exhaustion of the resource and construction destruction. Accidental character of operational loads under which influence an accumulation of fatigue damages in the components occurs, increase of structure loads as a result of the development of heavy-weight and high-speed movement, aging of the rolling stock with serving out the specified service life make timely the service life assessment, including residual life, basic (unexchangeable) parts of the operated locomotives. This assessment is necessary for confirmation of the possibility of their further safe operation. Application of the estimated and experimental methods of determination of the resource of locomotive load-bearing structures in the probable setting for an assessment and forecasting of its technical condition for the objective of ensuring safe operation with the required reliability during the given period is substantiated. Basic parts of the locomotives limiting the period of their service: locomotive frame (the main frame), bearing elements of the body, frames of the bogies. Considering the nature of loading in operation the resource of structure of the main frame (body) shall be determined based on the test results under the influence of longitudinal forces through automatic couplers including on mutual collision, and the calculations of bearing capacity of the structure on deformation criteria of low-cyclic fatigue. Frames of locomotive bogies mainly are working in the conditions of alternating multi-cycle loads. Their resource shall be evaluated based on the life cycle calculation on the indices of operational loading and resistance of the structural fatigue received based on the results of trial dynamic strength tests of the locomotive and bench trials on fatigue of the bogies frames with the expired service life. Recommendations on establishing the terms of safe operation depending on the locomotive type are given.
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