Probabilistic analyses and its application to life predictions of aircraft structures

by PDEng Frank Grooteman
12th May, 2021

Many aircraft are designed according to the deterministic damage tolerance philosophy to predict the crack growth life of the structure. Alternatively, a probabilistic damage tolerance analysis can be performed, called a structural risk analysis (SRA), taking into account all important scatter sources, such as, the initial flaw size, the inspection quality, the inspection scheme, the variability in loads and crack growth material properties, instead of using scatter and safety factors. For new military aircraft, SRA is mandatory. For current military aircraft, it already has become a valuable tool for fleet management, since it offers a risk (probability of failure) development over time, which cannot be obtained from the traditional deterministic damage tolerance analysis. By this, it better signals fleet management when to take corrective (maintenance) actions to prevent (critical) failures of the aircraft. This presentation will address the general concept of probabilistic analyses and its more specific implementation in the field of probabilistic fracture mechanics (SRA) using available fleet data. The approach will be supported by a number of examples.