Graded Modeling Method for Coated Blisks with Multi-Mistuning and Coating-Material Nonlinearity

Hard coatings have been used to reduce the vibration levels of blisks in several studies. In the design process, coating-geometric mistuning and blade-substrate multi-mistuning are inevitable; and even the coatings have material nonlinearity. However, this type of complicated blisk had never been studied previously. In this paper, a graded modeling method is presented to model the blisks with coating-geometric mistuning, blade-substrate multi-mistuning, and coating-material nonlinearity, where three reduction steps and a modified subspace iterative (MSI) method are developed to improve computational efficiency and accuracy. Several numerical analyses are performed to validate the developed models. The results indicate that for coated blisks with the aforementioned mistuning factors and material nonlinearity, the MSI-based reduced-order models (ROMs) have higher computational efficiency than the Craig-Bampton-based ROMs and full models, and they have higher computational accuracy than the frequency-based ROMs.

Automated summary

A graded modeling method is proposed in this paper to model complex blisks with coating-geometric mistuning, blade-substrate multi-mistuning, and coating-material nonlinearity. Numerical analyses demonstrate that the developed method has higher computational efficiency and accuracy compared to other reduced-order models.