Abstract
Safe operation of a ship engine plant is maintained using a continuous monitoring system and periodic inspection and maintenance undertaken several times daily. When monitoring and maintenance work are executed to judge the state of equipment, an operator uses data from measurement instruments and detects the operating sound of an engine and the hammering sounds from contact using a testing hammer.
The hammering inspection using the testing hammer, which is a general check method in routine maintenance work, is used not only for marine engines but also for various machines on land. In those machines, to prevent accidents, checking before engine starting is performed routinely, but many accidents caused by loose bolts and similar malfunctions are reported.
For this study, an experiment was performed while the fastening power of bolts in the connecting rod was variously changed. Sounds generated when bolts are hit with the testing hammer were recorded at that time. An operator heard the hammering sound. The means by which the operator judged the fastening power by the hammering sound were investigated using a questionnaire. In addition, the hammering sound was made into data, and calculation of the fastening power was assessed using statistical analysis based on the above data. Consequently, a multiple regression formula with high accuracy was obtained for particular bolts used for this experiment. Results clarified that the fastening power can be estimated from the hammering sound.
