抄録
In recent years, many investigations have been carried out to evaluate fatigue life of the components of combustion chamber on marine diesel engines, such as piston crown, cylinder head etc.
It seems, however, fairly difficult to evaluate accurately the fatigue life of these components in service conditions, since the scattering of material strengths and loads is pretty large and the service condition usually contains various factors which can not be realized in laboratory experiments. Therefore, the fatigue life evaluation of these components should be executed based on the probability of failures in service, similar to the way applied on the fatigue life design for air-plane, caraxle, etc.
In this first report, as a fundamental study for fatigue life design of the components of combustion chamber, the failure data of piston crowns in service were analysed statistically. It was confirmed that the type of failure distribution in service conditions was the logarithmic normal distribution, and the data of mean life, standard deviation, fluctuation coefficient were obtained. Also, the stress distributions on some components were analysed by FEM calculation and stress measurements.
