Strength and dynamic properties of the compound metal-matrix composite blade of the rotor in contact bearing supports

Based on analyzing structural strength and dynamic properties, using previously proposed methods for designing rotary machines, modeling various load types and contact behavior between rotor elements, as well as considering the impact of various types of bearing supports on the overall mechanical behavior, the work proposes a new rotor blade, composed of a steel root and an airfoil made of a metal-matrix composite, created to improve the rotor design and provide a counterweight to the challenges of turbomachine operation, in which the use of conventional extensive methods of structural strengthening cannot solve the functioning problems. The bimaterial blade variant considered in the work solves the practical engineering problem of easy replacement of quickly worn rotor blades of the mine main ventilation fan while maintaining their strength. The created blade design with a unique shape of the steel core suggested a cheap and easy-to-manufacture alternative to a solid aluminum blade, and the integrity of the connection of steel and composite parts was verified experimentally, as well as using computational methods with nonlinear contact formulations. This design underwent a multi-stage testing of strength and acceptability of the mechanical behavior of individual blades and the rotor containing them, which also showed good dynamic properties, refined by considering the influence of contact roller bearing supports. Based on the methods developed in the work, the dynamic behavior of a massive turbomachine rotor with a large-diameter disk and composite blades was simulated, which demonstrated the applicability of the proposed comprehensive approach including features of rotor loads and fixation, as well as the influence on this behavior of material characteristics, stiffness of contact roller bearing supports and disk and shaft compliance specified using proposed approaches.