Failure analysis of a gear wheel of a marine azimuth thruster

A failure analysis of two helical gear wheels of a ducted azimuth thruster is presented. research work consisted of a fracture examination of the material in order to determined damage root causes. The samples for the failure analysis were obtained from two bro teeth of two helical gear wheels. An analysis through the scanning electron micros (SEM) was carried out close to the crack initiation. It was found that the damage ir bevel gears were by the fatigue fracture mode. The SEM analysis showed that the gear t were under severe contact stress during the operation aggravated by an inapprop lubricating. A possible misalignment between the pinions and the gear wheels teeth c also contribute for the premature failure. (C) 2011 Elsevier Ltd. All rights reset