Probabilistic dynamics of mistuned bladed disc systems using Subset Simulation

The work describes an assessment of subset simulation (SubSim) techniques to increase the computational efficiency for the predictions of probabilistic dynamic behavior in mistuned bladed disc systems. Subset Simulation (SubSim) is an adaptive stochastic procedure to compute efficiently small failure probabilities, which are expressed as a product of large conditional failures probabilities by introducing intermediate failure events. The original version of SubSim is used in this work to simulate samples related to intermediate failure events. A 2-DOFs model with lumped parameters identified from a finite element model is used to represent a bladed disc. The statistics associated to the maximum forced frequency response amplitudes are evaluated from different levels of the blade mistuning using stiffness perturbation in the blades. The study shows the SubSim method capture efficiently the statistical properties of the mistuned blades with less than 1% of sample size that necessary for the traditional Monte Carlo method.