Review of Methods and Approaches for the Structural Risk Assessment of Aircraft

摘要

This report looks at the published literature on methods and assumptions made in performing structural risk assessments on aircraft. Because the major contributor to the risk of structural failure is fatigue, most methods of risk assessment involve modeling the effect of fatigue growth by some probabilistic method. Many risk assessments use the equivalent initial flaw size approach to allow for the variability in fatigue crack growth. Common errors in the formulation are made in many risk assessments, which can be significant and are described in this report. It is found that the standard approach can produce an acceptable assessment of the probability of failure of an aircraft if care is taken in understanding what is being modelled and the assumptions on which the analysis is based. A number of case studies of risk assessments performed on different aircraft are summarised.