Selection of an Acceptable Risk Criterion for Avoiding a Major Fatigue Failure on a Commercial Aircraft

摘要

This paper describes the calculation of crack-initiation and crack growth at afuselage lap-splice joint of a representative narrow-body jet airliner. Based onthese analyses, INSIM fatigue simulation software is used to calculate theexpected Cumulative Probability of Failure (CPOF) and the expected hazardratefor this representative aircraft. It is then shown that the maximumcalculated hazard-rate meets both the USAF and the very severe FAA criteria.The paper then shows that it is quite feasible to carry-out a full-scale fatigue testto three or more design lifetimes. Certain improvements to the INSIM softwarethat are planned for the next release are then described.