A quantitative assessment of the impact of corrosion on fatigue life of aircraft components. (March 2022)

• Record Type: Journal Article
• Authors: Kamath, Gopalakrishna M.; Mangalgiri, Prakash D.; Shet, Avinash
• Is Part Of: Engineering failure analysis. Volume 133(2022)
• Publication Date: 2022-03
• Subjects: Aircraft corrosion -- Corrosion-fatigue -- Aircraft life extension -- Damage tolerance -- Aircraft structural integrity; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2021.105973
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: Two scenarios studied: fatigue with prior corrosion and fatigue in corrosive environment. Aircraft horizontal stabilizer analyzed cycle-by-cycle under spectrum loading. Regions with only 82% of design stress became critical if susceptible to corrosion. Exposure to corrosive environment for even 25% duration showed 40–55% reduction in life. Abstract: Management of corrosion, and repair and restoration of corrosion‐affected structures pose a daunting challenge to the aircraft industry. This paper presents analytical studies to examine and quantify the effects of corrosion of Al-alloys on the fatigue life of aircraft structures. Two scenarios are considered: (i) fatigue of a pre-corroded material and (ii) fatigue in a corrosive environment. The corrosion damage is idealized using standard crack models, and cycle-by-cycle fatigue crack growth analysis is carried out for an aircraft horizontal stabilizer under spectrum loading conditions. A few aircraft operational scenarios are considered, and fatigue life calculations presented. The zone which experiences 18% lower stress than the maximum stress zone is shown to turn fatigue critical if vulnerable to corrosion. The results point to the risk posed by corroded zones if missed while focusing attention on high stress zones. The computations indicate that an exposure of even 25% of operational life to corrosive environment can reduce life by 40–55%. The study quantifies the significance of corrosion while arriving at design safe life, remaining useful life and maintenance intervals.