Keyword: «crack resistance»

The article describes the kinetics of the processes of damage accumulation of railway transport objects, as well as the dominating mechanisms for reaching their limit states. The evaluation is carried out for the characteristics of metal strength along with reliability and safety of structures with a decrease in temperature and their degradation during the operating life. For welded and cast parts, it is proposed to use steels with improved cold resisting properties. The necessity is shown for usage of constructive and technological methods to increase the service life of welded and cast parts. Сформированы актуальные задачи по реализации проекта освоения Севера и Арктики. Actual tasks have been formed for implementation of the project for the development of the North and the Arctic.

The article discusses the algorithm for confirming compliance with differentiated regulatory requirements for main pipelines welded pipes crack resistance. The results of laboratory tests for crack resistance CTOD of steel samples Type 3 and Type 4 according to GOST 25.506-85, obtained using the universal testing machine LFMZ-100, are presented. Also, refined formulas are given for calculating the values of the crack resistance parameter CTOD (GOST 25.506-85), obtained from the results of the numerical solution of the corresponding boundary value problems for two types of samples, performed by the finite element method using the ANSYS computer program.

The article presents the results of research on the use of fiber concrete as a material for the production of reinforced concrete sleepers. The advantages of dispersed reinforcement compared to traditional rod reinforcement are substantiated, and the regulatory requirements for concrete for underrail bases according to Russian standards are presented. The analysis of the composition of the fiber concrete mixture, the technology of molding, and the strength indicators is conducted. Recommendations are given for optimizing the dosage of steel fiber and the modes of heat and moisture treatment. It has been shown that the use of fiber concrete can increase the crack resistance, durability, and fatigue strength of sleepers, as well as reduce the labor intensity of production.