Comments on the formation of adiabatic shear bands in MGB planet pinions of a helicopter

Bhaumik, SK (2003) Comments on the formation of adiabatic shear bands in MGB planet pinions of a helicopter. Project Report. National Aerospace Laboratories, Bangalore.

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Abstract

Presence of Adiabatic Shear Bands (ASBs) was reported by a laboratory in failed MGB pinions as well as in the pinions withdrawn from service of a particular type of helicopter. The reports submitted to a helicopter manufacturer in this effect were examined at NAL, Bangalore. Study revealed that the white layers reported in the failed pinions were not present in the material before failure. It appears most probable that they were created during high strain rate fracture following the primary fatigue failure. The white layer reported in the withdrawn pinions does not have any characteristics of ASBs. They appear to be surface phenomena and would have occurred during service. It is possible that high local pressure during service has led to formation of these hard spots on the pinion tooth surface.

Item Type: Proj.Doc/Technical Report (Project Report)
Uncontrolled Keywords: Planet pinion;MGB;helicopter;adiabatic shear bands
Subjects: AERONAUTICS > Aeronautics (General)
CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
Division/Department: Materials Science Division
Depositing User: Mrs Manoranjitha M D
Date Deposited: 08 Jul 2011 16:29
Last Modified: 08 Jul 2011 16:29
URI: http://nal-ir.nal.res.in/id/eprint/9319

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