Modelling method and mistuning amplification analysis of the forced response for coated blisks in the presence of coatings-material nonlinearity

Abstract

Abstract Hard coatings have been employed to achieve the goal of vibration reduction for blisks in recent years. Nevertheless, the modelling method for randomly mistuned blisks with coatings-material nonlinearity and the effects of this nonlinearity on the amplification factors have not been investigated in previous studies. In this work, a linear reduced order model (ROM) for randomly mistuned blisks with linear coatings is developed by using the Craig-Bampton (C–B) method and an interface reduction technology firstly. Furthermore, the transformation matrices employed in the linear ROM is also used to reduce the dimension of perturbation matrices caused by coatings-material nonlinearity, and then the nonlinear ROM is developed and solved by an improved Newton-Raphson iterative process. Statistical analysis is performed to validate the developed models by comparing with the full models and to investigate the effects of coatings-material nonlinearity on the amplification factors for randomly mistuned blisks. The results suggest that the developed ROMS are in good consistency with the full models, and the amplification factors for the nonlinear analysis are decreased significantly with the force amplitudes increasing.