The modelling methods of blisks spraying hard coatings have been investigated in several works. However, the nonlinear strain dependence characteristics of coatings have been rarely incorporated in opened studies of the complicated coated blisks. In this paper, the Craig-Bampton (C-B) method is employed to establish the initial reduced order model (ROM), and then a second reduction method is proposed to develop the final linear ROM of linear coated blisks. By employing the model reduction transformation matrix from the linear ROM to reduce the perturbations matrices caused by the nonlinear strain dependence characteristics of the coatings, a nonlinear ROM is presented to simulate the coated blisks with nonlinear strain dependence characteristics. Furthermore, an iteration method based on this nonlinear ROM is presented to obtain the forced responses and the developed models are verified by full models. The effects of nonlinear strain dependence characteristics on forced responses of coated blisks are analyzed. The results suggest that with the increasing of the excitation force amplitude, the maximum forced responses computed from the nonlinear model are significantly decreased compared with those from the linear model.

strain dependence characteristics; reduced order model; coated blisks; forced responses