Method for correlation of failure data from durability tests and field of automotive engine parts with spontaneous failure mode

摘要

Determining of the level of fatigue present in components that were used in the field, is an important basis for the implementation of accelerated testing. This paper presents a method which enables fatigue determination of intact but pre-aged components that fail spontaneously. In the beginning components which have been field tested are exposed to additional laboratory testing. Then a fictitious lifetime is computed from the weighted sum of the field lifetime and the laboratory lifetime. These components are then compared against pure laboratory-aged, reference parts using the maximum-likelihood method as the comparison criterion. The weighting coefficient is then determined so that the distribution of the fictitious lifetime agrees well with that of the reference parts. Finally the ratio of the failures can be derived from the comparison of field-aged and laboratory tested parts.