In this paper, the quantification of uncertainty effects on the variability of the non-linear response in rotor systems with multi-faults (such as unbalance, asymmetric shaft, bow, parallel and angular misalignments) is investigated. To take account of uncertainties in this kind of non linear problem, it is proposed to use the Harmonic Balance Method (HBM) with a Polynomial Chaos Expansion (PCE). The efficiency and robustness of the proposed methodology is demonstrated by comparison with Monte Carlo Simulations (MCS) for different kinds and levels of uncertainties.

In this paper, the quantification of uncertainty effects on response variability in rotor systems is investigated. To avoid the use of Monte Carlo simulation (MCS), one of the most straightforward but computationally expensive tools, an alternative procedure is proposed. Monte Carlo Simulation builds statistics from responses obtained from sampling uncertain inputs by using a large number of runs. However, the method proposed here is based on the stochastic finite element method (SFEM) using polynomial chaos expansion (PCE).The efficiency and robustness of the method proposed is demonstrated through different numerical simulations in order to analyze the random response against uncertain parameters and random excitation to assess its accuracy and calculation time.