Among many dimensional and dimensionless amplitude parameters, Kurtosis (4-th normalized moment of probability density function) is generally regarded as a sensitive good parameter for machine diagnosis. In this paper, a simplified calculation method is introduced when impact vibration arise in the observed data. The case in which the rolling elements number is nine is examined. Compared with the past papers' results, this new method shows a good result which fit well. This calculation method is simple enough to execute even on a pocketsize calculator and is very practical at the factory of maintenance field. This can be installed in microcomputer chips and utilized as a tool for early stage detection of the failure.
Mathematics Subject Classification: 60G35
Keywords: impact vibration, probability density function, kurtosis, rolling element