Yusoff N.H.N.,Marine Materials Research Group |
Isa M.C.,Marine Materials Research Group |
Muhammad M.M.,Marine Materials Research Group |
Nain H.,Marine Materials Research Group |
And 3 more authors.
Defence S and T Technical Bulletin | Year: 2012
This paper presents a failure analysis conducted for a shaft coupling used in a ship's propulsion system, which failed while running at low speed during a sea trials assessment. The fracture occurred at the connection between the cylindrical parts and flange. A detailed metallurgical investigation was carried out to determine the failure initiations and failure mode. The failure was dominated by fatigue due to the appearance of ratchet marks, which were as a result of multiple fatigue cracks propagation, linking each other. Based on the marks' direction, it was determined that the failure was influenced by low load and high stress concentrations of torsion. The initial failure point was found at the keyway throughout the beach marks present. Higher magnification of cracks region found that the crack growth was induced by pitting corrosion.