Detection of blade substrate crack parameters of hard-coated blisk based on mistuning identification technology

The detection of blade substrate crack is crucial for the safe operation of hard-coated blisk. Due to the coating coverage, it tremendously increases the difficulty of crack size and location detection. This paper presents a novel method based on the mistuning identification technique to detect the blade substrate crack parameters (including crack size and location) for the hard-coated blisk. Different from previous studies, the stiffness mistuning caused by substrate crack is taken as the quantitative parameter to detect crack parameters in this method. A method to identify the stiffness mistuning of blade substrate crack using only modal data is presented based on the reduced- order model of blisk. The basic data sets of substrate crack stiffness mistuning need to be established by finite element simulation. The crack mistuning basic data sets and crack mistuning under the first and second bending modal families are matched to determine the crack parameters. A crack detection procedure is presented based on these theories. The effectiveness of the detection method is verified by numerical and real cases. The results show that the method can effectively detect the crack parameters of all blades at one time, which has high detection efficiency. It also appears that the detection accuracy of the crack location is higher than that of the crack size. Finally, the rule of the detection accuracy changing with the crack parameters is studied. The results show that the proposed method has a good and stable identification accuracy for cracks in a specific size and location range.

Automated summary

This study presents a novel method to detect the parameters of blade substrate cracks in hard-coated blisks, utilizing mistuning identification technique and finite element simulation to establish basic data sets. The method proves to effectively detect crack parameters for all blades with high efficiency, showing higher accuracy in crack location detection than crack size detection. The proposed method exhibits good and stable identification accuracy for cracks within a specific size and location range.