The vibration signature of chordal cracks in a rotor system including uncertainties

Jean-Jacques Sinou (1) , Béatrice Faverjon (2)

1 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes
2 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]

The aim of this paper is to investigate the effects of the presence of a transverse crack in a rotating shaft under uncertain physical parameters in order to obtain some indications that might be useful in detecting the presence of a crack in rotating system. The random dynamic response of the cracked rotor is evaluated by expanding the changing stiffness of the crack (i.e. the breathing mechanism) as a random truncated Fourier series. To avoid the use of the Monte Carlo simulations (MCS), an alternative procedure that is based on a combination of the Harmonic Balance Method and the Stochastic Finite Element Method (SFEM) using the Polynomial Chaos Expansion (PCE) is proposed. So the response of the Fourier components of the cracked rotor is expanded in the polynomial chaoses. The random dynamic response obtained by applying this procedure is compared with that evaluated through numerical integration based on the Harmonic Balance Method and the Monte Carlo simulations.

Mots clés: crack; vibration; rotor; uncertainties

Domaines: Vibrations [physics.class-ph]; Vibrations [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des structures [physics.class-ph]; Mécanique des structures [physics.class-ph]; Systèmes dynamiques [math.DS]

Jean-Jacques Sinou, Béatrice Faverjon. The vibration signature of chordal cracks in a rotor system including uncertainties. Journal of Sound and Vibration, 2012, 331, pp.138-154. ⟨10.1016/j.jsv.2011.08.001⟩. ⟨hal-00630417⟩