A Sensitivity-Based Method for Direct Stochastic Analysis of Nonlinear Forced Response for Bladed Discs With Friction Interfaces

An efficient method is developed to calculate stochastic and uncertainty characteristics of forced response for nonlinear vibrations of bladed discs with friction and gap contact interfaces. Uncertainty ranges, statistical characteristics and probability density functions for forced response levels are determined directly without any sampling procedure. The method uses approximations of the forced response level based on derived analytically and calculated extremely fast and accurately sensitivity coefficients of forced response with respect to friction contact interface parameters. The method effectiveness allows analysis of strongly nonlinear vibration of bladed discs using realistic large-scale FE element models. The method is implemented in a program code developed at Imperial College and numerical examples of application of the method for stochastic analysis of a realistic blisc with underplatform dampers are provided.