Empirical Data-Based Failure Rate Assessment Methodology for Metal-Cutting Tools

The type of distribution law and its parameters reflect the physical essence of the technical object failure. Simultaneously, the failure rate is the leading component of this process as it solely defines the type of distribution law. The paper analyzes the nature of the failure rate function in the context of research and assurance of technical object reliability. It was shown that several approaches exist to determine the failure rate based on empirical data. Still, assessment of these approaches from the point of view of their adequacy is absent. No attention was paid to analyzing distribution laws from the point of view of failure rates compliance with empirical data. A criterion based on the maximum likelihood method was proposed for evaluating the empirical failure rate compared with the one obtained based on the theoretical distribution laws. It was shown that the most plausible estimate of empirical failure rate can be obtained using the average number of operational objects in a specific time interval, compared to its theoretical value obtained based on theoretical distribution law as a function of the middle of the same interval. It was shown that the proposed criterion can be used as an additional argument when choosing a theoretical distribution law based on empirical data when the goodness-of-fit criteria do not allow for drawing an unambiguous conclusion. In this case, the correspondence of the theoretical distribution law to the physical processes causing the failure of the technical object will be ensured.