VNCCD: A gearbox fault diagnosis technique under nonstationary conditions via virtual decoupled transfer path

The interconnection between different components among a gearbox poses a challenge in decoupling vibration signals for fault diagnosis. This study presents a method called Virtual Non-Linear Chirp Component Decoupling (VNCCD) to address gearbox fault diagnosis. The method starts by identifying the decoupled frequency response function (DFRF) using a virtual decoupling method. The bearing force signals are then computed based on the DFRF, and the intrinsic signal components are extracted using a nonlinear chirp mode decomposition technique. The proposed approach enhances the quality of vibration signals in gear systems by eliminating the intercoupling effect of structural transfer paths. By employing the VNCCD method, the amplification of fault conditions can be effectively demonstrated compared to the nonlinear chirp component obtained from the original signal. Simulation and experimental results confirm the effectiveness of the VNCCD method in diagnosing gearbox systems that experience intricate structural transfer paths in nonstationary conditions.