Assessment of Natural Oscillation Frequencies of Rotor for Development of Hard-Bearing Balancing Machine

Abstract

An imbalance appears during the manufacture, operation, and maintenance of power equipment. The rotor imbalance arises due to the unbalanced masses of the rotor which leads to the emergence of variable loads on the supports and bending of the rotor. The dynamic balancing of the rotor on the balancing machine is the way to avoid the negative effects of centrifugal forces. The balancing machines in resonant and soft-bearing modes are usually used on modern production. However, the soft-bearing method of balancing has a number of shortcomings, which can be solved by using the hard-bearing method. In particular, by using the hard-bearing method, it is possible to balance products with large initial imbalances and to increase the accuracy of balancing. The Autodesk Inventor CAD software was used for modeling of the balancing machine and the rotor. The modal analysis was conducted by using the block method of Lanczos on the basis of the ANSYS. The main assumption during the modal analysis process was that the form of free fluctuations is calculated in relative units and does not allow one to determine absolute shifts. The application of soft-bearing balancing method needs to be added in other ways, taking into account high requirements of the power equipment. A model of a hard-bearing balancing machine was designed for balancing rotors and rotating elements of power equipment. The natural oscillation frequencies of the 3D models of the balancing machine bed and the rotor of the gas turbine engine 16M were calculated to determine the informative frequency range that the rotor should be hard-bearing balanced.