Foundation of damage tolerance principles in‐service for the RRJ‐95 aircraft structural components

Abstract

Fatigue cracks initiated from holes in several zones and structural components of the RRJ‐95 aircraft frames were investigated. Using the method of quantitative fractography, the crack growth duration in the wing panels during full‐scale bench tests and in the brackets of the in‐service airframe was estimated by measuring the spacing of meso‐beach‐marks (MBM) and fatigue striations. The applied program of bench test consisted of blocks of variable loads that were equivalent to the wing loading in flight and reproducing schematized flight‐cycle. It was shown that the duration of fatigue crack propagation in several structural components of the RRJ‐95 aircraft frames was approximately the same as for the crack nucleation duration. The total lifetime is sufficiently long for cracks in the structural components to be detected and reliably monitored with a large operating time interval between adjacent inspections.

The in‐service fatigue fracture mechanisms for the I‐stage low‐pressure compressor disk of the aircraft engine D30KU‐154

“…Considering all these factors of probability, a reasonable inspection and maintenance period can be established only for the cracks that have already nucleated and been detected. The difficulty in accurate prediction and the variability of reasons leading to operational fatigue fractures causes significant scientific interest in this problem 1–15 …”

“…The difficulty in accurate prediction and the variability of reasons leading to operational fatigue fractures causes significant scientific interest in this problem. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] It is well known that fatigue is the main reason of the operational fatigue fracture for aircraft elements. 1 Because of the complex multiaxial loadings of aircraft structures and wide amplitude and frequency spectrum of the loads, different aircraft structures can experience all known fatigue regimes from low cycle fatigue (LCF) to very high cycle fatigue (VHCF).…”

Virtual special issue: Variable amplitude loading—Fracture mechanics and cumulative damage modeling

“…Shanyavskiy et al 11 outlined some basic principles of the damage‐tolerance concept for structural components of commercial aircraft as well as examples of crack formation and propagation determined in full‐scale bench tests as well as those found on in‐service aircraft. The basic process of the detailed evaluation of the fatigue loading and crack growth and the derivation of inspection intervals was presented.…”