Research on Stamping Crack Detection Method of Pulley Based on NOFRFs

Abstract Pulley is the key component in mechanical transmission systems, which may be prone to cracks during the stamping process. Detecting these defects is therefore critical. The nonlinear features of the system's fracture damage can be accurately reflected by nonlinear output frequency response functions (NOFRFs). In this study, the NOFRFs-based indices are employed for detecting stamping crack in components. The effects of two distinct excitation modes, harmonic excitation and pulse excitation, are compared. The sensitivity and stability of the NOFRF-based indices under harmonic excitation are higher. Under both excitation methods, the accuracy of the NOFRF-based damage detection indices exceeds 80%. Furthermore, this study finds that the single-frequency harmonic excitation, compared to swept-frequency harmonic excitation, can also achieve crack detection. Meanwhile, the accuracy of entropy index of the response signal is relatively low.