PSI - Issue 30

N.A. Makhutov et al. / Procedia Structural Integrity 30 (2020) 87–92 N.A. Makhutov et al. / Structural Integrity Procedia 00 (2020) 000–000

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a

b

d

c

Fig. 4. The most dangerous, poorly detectable operational defects: (a) metal shelling on the running surface due to the presence of a metallurgical surface defect near the joint; (b) rail metal shelling in the bolted joint; (c) a typical fatigue crack in the rail head; (d) a large transverse fatigue crack originating from a flake in the head centre (defect 20); 1 is a fatigue fracture focus; 2 is the area of a gradual development of a fatigue crack itself; 3 is a break area; 4 are steps and scars on the fatigue crack surface; 5 are fatigue lines or rings of a gradual growth; 6 is the area of a brittle slipping; 7 is a flake (in the form of a granular surface tear); 8 are fatigue lines in the form of circumferences. In addition, the pressure in the wheel-rail contact is an important factor defining the damageability of rails. This pressure, in turn, depends on the track condition and axle load. Results of a comparative design analysis of the rail service life, performed using Brown – Miller multiaxial fatigue models in MSC.Fatigue software package, confirm that the service life of rails decreases with increasing axle loads by Brown et al. (1973). Thus, adding of 20 % of freight trains with axle loads of 25 tf to the current flow of freight trains with axle loads of 23.5 tf in a day pass of trains, one should expect a decrease in the contact fatigue life of rails by 3–4 %. 4. Conclusions In relation to the above mentioned, tasks included in the work scientific support program to implement the project “The creation of the Northern Latitudinal Railway” become relevant, in particular: • The analysis of the state of technical requirements, current standards for materials to build rolling stock and track superstructure for the operation in the climatic area of the Northern Latitudinal Railway and the Far North • The development of technical requirements to structural steels and other materials for railway technical equipment in relation to conditions of the Northern Latitudinal Railway