The compound fault interaction analysis of the planet bearing system

This paper aims to understand the bearing distributed–localized compound fault interaction in planetary bearing system. To reveal the compound faults coupling mechanism, the planetary gear bearing distributed–localized fault mathematical models were proposed to obtain the dynamic response in the presence of various planet bearing distributed–localized compound fault combinations. The instantaneous angular speed (IAS) measured from the carrier arm has been pre-processed with the consideration of different distributed–localized fault interactions and treated as inputs for the coherence estimation analysis, which has been used as a tool for the individual fault contribution quantification. Six representative bearing compound fault cases have been selected and the results show that the existence of the bearing compound faults interaction phenomenon can weaken the localized fault characteristic frequencies for the bearing fault diagnosis. However, the localized fault still contributes more than the distributed fault on the same bearing component on the condition that the fault magnitude is the same.