I.B OWUNNA

The propeller shaft is a critical component in marine propulsion systems, transmitting power from the engine to the propellers. In twin-screw passenger ferries, failure of the propeller shaft can lead to severe operational disruptions, safety hazards, and costly repairs. This study presents a comprehensive failure analysis of a propeller shaft from a twin-screw passenger ferry to determine the root cause of failure and suggest mitigation strategies. The investigation includes visual inspection, non- destructive testing (NDT), metallurgical analysis, and finite element analysis (FEA) to evaluate material properties, fatigue characteristics, and stress distribution. The findings indicate that fatigue failure, corrosion-assisted cracking, misalignment, and improper lubrication are potential contributing factors. Based on the results, recommendations for improved maintenance, material selection, and design modifications are proposed to enhance the reliability and longevity of propeller shafts in marine vessels. This study provides valuable insights into preventing similar failures in future maritime applications.

In Nigeria today and in the world at large, PET bottle waste has grown to become hazardous as it constitutes part of the non-biodegradable waste. Hence, recycling becomes necessary to curb its menace. This project work is centered on designing and fabricating a PET bottle crushing machine from locally sourced materials for both home and industrial use in an attempt to proffer solution to the PET waste problem in Nigeria. Preliminary tests and mechanical factors were extensively evaluated on the conceptual designs to ensure that the design that most suits the purpose was selected and detail design was carried out. Experiment to determine the power required to overcome the shear resistance of the PET bottles was carried out and it was discovered that 10hp at 450N was the power required. Finite element analysis was also performed on the cutting blade to inspect
the materials response to stresses and the corresponding deformation. Furthermore, a design study was carried out in order to ascertain the minimum and maximum loads that can be handled. Tests carried out on the machine showed its efficiency to be 82.2% which is only 6% less than the efficiency of foreign counterparts