Probabilities of occurrence and detection of damage in airframe materials

• Published in: Fatigue & fracture of engineering materials & structures 1999-05, Vol.22 (5), p.427-436
• Main Authors: Harlow, D. G., Wei, R. P.
• Format: Article
• Language: English
• Subjects: ageing aircraft; airworthiness; Applied sciences; corrosion fatigue cracking; Exact sciences and technology; Fatigue; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; pitting corrosion; probability of detection; probability of occurrence
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1046/j.1460-2695.1999.00168.x

The reliability of airworthiness assessment and the effective management of ageing fleets of aircraft depend critically on the quality of tools for predicting damage nucleation and accumulation and its detection, i.e. on the interrelationship between the probabilities of occurrence and detection. To illustrate these interrelationships, a mechanistically based probability approach involving localized pitting corrosion and subsequent fatigue cracking is presented. A probability of detection based on a typical state‐of‐the‐art technique for non‐destructive evaluation is used for comparison and probabilistic assessment. The results suggest that the probability of detection is inadequate, and information on damage size should be included as part of an effective airworthiness assurance methodology. An appropriate target for detecting and sizing damage of ≈ 0.10 mm with a probability of detection and a confidence level of at least 90% is suggested, versus the current capability of 1.27 mm at only 50%