Failure Analysis of Cooler Fan Drive Gear System of Helicopter

Manda, Premkumar; Singh, Satyapal; Singh, A.K.

doi:10.1016/j.matpr.2017.12.108

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…Yu and Xu [23] also observed a cross-section near the fracture of 42CrMo steel gears using a Scanning Electron Microscope (SEM), and found the microstructure of the core consisted of tempered sorbite and ferrite. Manda et al [32] further found that martensite grains of failed gears were larger than their counterpart of unfailed gears. Guagliano et al [33] utilized SEM to study the trend in micro-cracks leading to spalling of the tooth flank.…”

Section: Introductionmentioning

confidence: 95%

Contact Fatigue Failure Analysis of Helical Gears with Non-Entire Tooth Meshing Tests

Zhao

Ding

Fan

et al. 2018

Metals

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This study presents an experimental approach based on partial tooth meshing contact fatigue with constant amplitude and different lengths of load cycles. To achieve this, 20CrH helical gears were considered, limiting the region of interest to one-third of the tooth to accelerate crack initiation and propagation. Different factors, such as number of fatigue cycles, tooth flank morphology, residual stress, hardness, and microstructure evolution under fatigue, were considered. The ultimate goal was to relate these variations with the observed failure modes. The results showed that with increasing cycle number, the residual stress at the same position in the meshing zone of the tooth flank increased first and then decreased. The residual stress values at the lower position of the pitch circle were larger than that of the addendum and dedendum. After cyclic loading, the content of the twin martensite within the microstructure below the pitch circle decreased and the corresponding hardness value of the tooth flank was reduced. After long-term cyclic loading, the precipitated phases aggregated and grew and the discontinuous distribution hindered the grain boundary slip. The dislocation density increased, and the pile-up of dislocation resulted in stress concentration at the grain boundary and the phase boundary, which induced the initiation of fatigue crack of the tooth flank.

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Section: Introductionmentioning

confidence: 95%

Contact Fatigue Failure Analysis of Helical Gears with Non-Entire Tooth Meshing Tests

Zhao

Ding

Fan

et al. 2018

Metals

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“…The design of gears incorporates a high factor of safety to ensure long service life [1]. However, gears are still reported to fail in active service which can lead to operational downtime and economic losses [2][3][4][5][6][7][8][9][10][11][12][13]. The reasons for failure in gears before the end of the specified service life can broadly be categorised into three categories: Fault in design (like a low factor of safety, gear geometry errors and poor material selection), Fault in manufacturing (like metallurgical inclusions, improper heat treatment and machining marks) and Fault due to application (like installation errors and poor lubrication) [3].…”

Section: Introductionmentioning

confidence: 99%

Mathematical Complexities in Modelling Damage in Spur Gears

Oreavbiere,

Khan

2024

Machines

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Analytical modelling is an effective approach to obtaining a gear dynamic response or vibration pattern for health monitoring and useful life prediction. Many researchers have modelled this response with various fault conditions commonly observed in gears. The outcome of such models provides a good idea about the changes in the dynamic response available between different gear health states. Hence, a catalogue of the responses is currently available, which ought to aid predictions of the health of actual gears by their vibration patterns. However, these analytical models are limited in providing solutions to useful life prediction. This may be because a majority of these models used single fault conditions for modelling and are not valid to predict the remaining life of gears undergoing more than one fault condition. Existing reviews related to gear faults and dynamic modelling can provide an overview of fault modes, methods for modelling and health prediction. However, these reviews are unable to provide the critical similarities and differences in the single-fault dynamic models to ascertain the possibility of developing models under combined fault modes. In this paper, existing analytical models of spur gears are reviewed with their associated challenges to predict the gear health state. Recommendations for establishing more realistic models are made especially in the context of modelling combined faults and their possible impact on gear dynamic response and health prediction.

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