PSI - Issue 59

O. Fomin et al. / Procedia Structural Integrity 59 (2024) 523–530 529 Oleksij Fomin, Oleksandr Kozinka, Vadym Ishchenkoc, Oleksij Burlutskyy / Structural Integrity Procedia 00 (2023) 000 – 000 7 replaced, and the associated repairs tend to be relatively expensive. Researchers from Australia's Melbourne Royal University of Technology, led by Professor Adrian Mauritz, have proposed a new method for repairing damaged composites. According to the university's announcement, the new development is a polymer spray that can be applied to the site of damage to the composite and thus repair it. Australian researchers have successfully developed a novel polymer commissioned by the Australian Ministry of Defense and the US Navy. This advanced polymer comes pre-loaded with fibers. Maurits, the project lead, highlights that this polymer, available in a convenient spray form, can be applied directly to the damaged site of a composite part without the need for intricate pre-treatment. Remarkably, it undergoes rapid hardening within a mere ten minutes post-application. Also, this spray can be used to repair damage to warships. If a warship or aircraft has a damaged composite, they must be decommissioned and require lengthy, expensive repairs. The new technology allows it to be performed immediately and directly at sea. The invented polymer is sprayed onto the surface of cracked or damaged fibrous composite parts. According to the scientists, it takes about 10 minutes to restore them. Earlier, the British company ELG Carbon Fiber announced the development of a method of annealing composite materials to remove polymer from them and further use of thermally purified carbon fiber in the production of composite parts for wagons. You can also use polymer composite repair with Belzona materials (Fig. 8).

Fig. 8. Repair composite material Belzona.

Belzona composite material is a two-consisting of: - the base of the glue is epoxy resins, which ensure its homogeneity and plasticity; - filler - metal component; - additional substances.

This technology is used in a large number of industries. In particular, for restoration of bearing seats, threading by cold welding, repair of cracks in cast iron, repair of cracks in housings (gearbox, engine blocks), repair of rubber technical products. Repair with polymer materials is a modern way to return the unit to working condition, significantly saving on the purchase of a new one. 4. Conclusions The main causes of body malfunctions are violations of the rules for loading and unloading cargo, violations of the rules for maneuvering operations, and violations of the technological process of repair and control. Malfunctions and damage to the wagon bodies and wagon frames are diverse and depend on the operating conditions of the wagon and its design features. Defects of bodies: skew of the body more than 75 mm, the gap between the pivot beam and the side frame of the bogie in loaded tanks is less than 30 mm, the expansion of the wagon body more than 75 mm on one side, etc. Defects of the body frame: longitudinal cracks in the beams of the frame longer than 300 mm, cracks in the upper heel plate (flange) of the heel longer than 30 mm, etc. Thanks to the development of new wagons made of composite materials, it is possible to achieve improvements in technical and economic characteristics and new design solutions aimed at increasing operational reliability. The improvement of the body structure reduces the frequency of receiving open wagons for current repairs, ensuring the