Mechanical connection of metal structures in wagon buildings
2021
Zaripov, R., Toraighyrov Univ., Pavlodar (Kazakhstan) | Gavrilovs, P., Riga Technical Univ. (Latvia)
The article reflects information from the field of designing freight railwagons. The issue of assembling elements of a freight wagon body made of aluminium alloy without welding is considered. The results of testing pins with a crimp head are presented. Crimp head pins are used as an alternative to welding. Such connections have the advantages of both rivet and bolt connections. They eliminate the shortcomings of the bolted connection, in particular, the weakening of the bolt tension as a result of unscrewing the nut during vibration. For the correct choice of the number of connections, it is necessary to determine the load-bearing capacity of a single connection under different loads (static, cyclic, shock), taking into account the actual operating conditions of the connected body components. The proposed samples simulate the working conditions of individual body elements. Based on the test results of model samples, it is possible to determine the load-bearing capacity of pins with a crimp head of the selected type and calculate the number of connections that can withstand standard loads without destruction during the specified service life of the wagon. The tests have shown that the strain relief and loosening of the pins with the crimp head occur at different impact energies, depending on the amount of preload and the size of the connection parts. In the tests of joints with samples of aluminium profile it was found that proper selection of the type of pins and crimping heads, as well as the number of joints of individual elements of the freight wagon body of aluminium alloy ensure long-term usage of the body without damaging the base metal and the joints. The tests have shown that unloading from interference and weakening of the PwCH connection occurs at different impact energies, depending on the amount of preload and the dimensions of the details of the PwCH connection: PwCH connections with a crimping head with an internal diameter of 16.6 mm – 1.25 kJ (total with an interference fit of 500 MPa); PwCH connection with a crimping head with an internal diameter of 17.0 mm – 0.15–0.25 kJ; PwCH connection with a crimping head with an inner diameter of 16.65 mm – 1.5–2.0 kJ.
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