چكيده به لاتين
Abstract:
In general engineering practice, one key factor in designing a motor built-in high-speed spindle is to assemble the motor rotor and shaft by means of hot-fit to form a new rotor-shaft assembly. When rotors operate in supercritical speeds, a phenomenon known as rotordynamic instability may occur. This can be brought about by internal friction occurring both in the material and in the structural elements, gyroscopic effects, and it is a cause of self-excited lateral vibrations.
Always the dynamical characteristics in interference fit such as damping, stiffness, has been the subject of researches. Another approach that is taken for this mention to be an equivalent localized Young’s modulus as the local stiffness to account for the additive interference fit rotor.
In this thesis, the dynamic analysis of a shrink-fit rotor in a rotor-shaft assembly of turbine rotor built in OTC Company by using 3D contact element is proposed. Contact pressure between the rotor and the shaft is firstly calculated through contact theory. The stress state is thus determined. The finite element modal analysis then follows with the stress state as a pre-stressed condition. The accuracy and the validity of the finite contact element results are verified by theoretical formulation. The results presented herein indicate that it is accurate and effective in analyzing the dynamic behavior of the rotary shaft system with a shrink-fit component by using contact element. In the following, Campbell diagram are conducted to evaluate the critical speed, although it has been non-linear analysis. Finally the results of the unbalanced response analysis are conducted for different interference fits. Campbell diagram and unbalance response analysis is a new work in this filed.
Keywords: Interference Fit; contact element; rotor- shaft assembly; rotor stability; high-speed spindle.
