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Investigation of tribologic processes in bearing nodes with the use of the FAM-C and FDM-A methods – the model with elevated passive resistance

Gębura A.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

2014

nr 35

115—125

The paper discloses selected results of application of the FAM-C (a.c. generator) and FDM-A (d.c. generator) methods for comprehensive troubleshooting of bearing nodes in single-spool turbojet engines. A.c. generators provide information about slow-changing processes and, consequently, that information makes it possible to monitor radial and axial clearance of bearings as well as misalignment of shafts. On the other hand, the information transmitted by d.c. generators refers to fast-changing processes and is suitable to monitor dynamic properties of antifriction bearings: variations in the Q factor of bearings, slip factor of mating antifriction surfaces, rates of bearing cage rotation against its journal, etc. Nearly ten years of observations and data collection from a numerous set of engines during their operation have made it possible to classify processes associated with wear of bearings and categorize them into four phenomenological models. This paper is devoted to the model of elevated passive resistance.

Evaluation of Steering Disks in Mi-17 and Mi-24 Helicopters by Means of the Fam-C Method

Kurdelski M., Gębura A.

Prace Naukowe Instytutu Technicznego Wojsk Lotniczych

2013

nr 33

127--158

The paper deals with selected issues related to operation of steering disks designed for helicopters that are currently in operation of the Air Force of the Republic of Poland. The attempt is made to present a prediction of hazards to the transmission gear of that helicopter where the forecast is based on a theoretical analysis of mechanical phenomena as well as the statistical and diagnostic analyses. The major attention is paid to the opportunity to diagnose hazardous locations of the helicopter steering disk with use of a non-destructive FAM-C method originally developed by ITWL. The method is based on tracking of frequency modulation parameters generated by the on-board AC generator. The examination does not require the installation of any additional sensor since the transmission is subjected to neither additional load nor distortions of the rotation speed occur. The authors of this study disclosed the initial results from diagnostic measurements as well as snapshots taken during the disassembling of steering disks from Mi-24 and Mi-17 helicopters that were operated under heavy duty conditions of military missions in Iraq and Afghanistan. They also suggested an easy and cheap method for field checking of the steering disk bearing by photogrammetric measurements. It is also demonstrated that the method of diagnostic investigations can be also spread onto other helicopter makes and types.