Bending Critical Speed Determination of a Shaft Carrying Multiple Rotors by Vibroacustical Signal Analysis

Autor: Liviu Bereteu, Ion Crastiu, Dorin Simoiu
Rok vydání: 2020
Předmět:
Zdroj: New Advances in Mechanisms, Mechanical Transmissions and Robotics ISBN: 9783030600754
DOI: 10.1007/978-3-030-60076-1_34
Popis: The main purpose of this paper is to estimate the first natural frequency of a mechanical system consisting of a shaft that carries multiple rotors by analyzing a vibroacoustic signal obtained from a mechanical impulse applied to the system. From the first frequency it is easy to determine the critical bending speed. Experimentally, the vibroacoustic signal is taken over by a condenser microphone that acts as an acoustic sensor. The Finite Element Method (FEM) is used to numerically determine the natural frequencies and natural modes of a multi-rotor shaft specimen. The mechanical impulse is applied in the boundary conditions used for numerical analysis. Two cases of border conditions are analyzed. In the first case the simple supported shaft (SS) is considered, and in the second case the shaft is considered with free ends. From an experimental point of view for the SS case, this is done by supporting the shaft on two sharp prismatic edges. If the ends are free, the shaft is suspended by two elastic threads by a support bracket. The vibroacoustic response is analyzed using the algorithm given by Fast Fourier Transform (FFT). An analytical method based on the Rayleigh-Ritz method is also used to compare the results.
Databáze: OpenAIRE