Dynamic modeling of gear compound faults and stiffness sensitivity analysis against arbitrary spatial configuration of defect

Gear systems play a crucial role in various machines to transmit power and motion. One common issue in the gear systems is the frequent gear collision, which results in increased wear and tear, and ultimately, damage to the gears. Consequently, the gear faults tend to develop in a compound manner rather than in isolation, i.e., a faulty gear often encompasses multiple defects, such as pitting, cracking, and so forth. Nevertheless, the existing literature has primarily centered on the gear model with a single fault, leaving a research gap in the modeling of compound faults. Further, to elucidate the root causes behind the degradation of gear systems, it is necessary to figure out the relationship between the intrinsic characteristics of gear systems and the progressive development of compound faults of gears. To address these issues, this paper proposes a compound fault gear modeling method with a generic framework to handle arbitrary spatial configuration of compound faults. The compound fault gear model is then verified by finite element model (FEM). Further, the relationship between the progressive development of gear compound faults and the evolution of time-varying meshing stiffness (TVMS) of gears is investigated, presenting a detailed comparison of the sensitivity of TVMS to different spatial configuration of gear faults. The results offer a promising avenue for modeling machinery degradation with compound faults, paving the way for a more comprehensive understanding of the intricate dynamics involved in the degeneration of gear systems.