Investigating the influence of bearings elastic properties on nonlinear dynamics of unbalanced induction motors shaft in presence of asymmetric magnetic pull

Authors

1 Department of Mechanical Engineering, Hakim Sabzevari University

2 Department of Mechanical Engineering, Engineering Faculty, Hakim Sabzevari University, Sabzevar, Iran

3 Department of Mechanical Engineering, Hakim Sabzevari University. Iran

Abstract

This paper aims to investigate the influence of bearing elastic properties on nonlinear dynamics of unbalanced rotors. Accounting for the influence of asymmetric magnetic pull, the governing equations of motion associated with the rotor are obtained using the nonlinear Euler-Bernoulli beam theory. Adopting the Galerkin projection method, the reduced equations of motion are extracted and then solved analytically through the method of multiple time scales for the cases of free vibrations and primary resonances. Aside from the numerical simulations, the present findings are compared and successfully validated by those published in the previous studies. Afterward, a detailed parametric study is conducted to assess the influences of asymmetric magnetic pull, nonlinear stiffnesses of the bearings and the eccentricity on nonlinear dynamics of the system. Results reveal that accounting for the influence of asymmetric magnetic pull decreases the natural frequencies of the system. In addition, it is observed that increasing the eccentricity increases the amplitudes of vibrations and also broadens the bistable resonance zone.

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References

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Journal of Solid and Fluid Mechanics
Volume 13, Issue 5
November and December 2023
Pages 137-153

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