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About this book

This book provides a concise discussion of fatigue crack growth (FCG) failure and lifing analysis methods for metallic aircraft structures and components. After a reasonably concise historical review, surveys are made of (i) the importance of fatigue for aircraft structural failures and the sources of fatigue nucleation and cracking, (ii) contemporary FCG lifing methods, and (iii) the Quantitative Fractography (QF) required for determining the actual FCG behaviour. These surveys are followed by the main part of the book, which is a discussion, using case histories, of the applicabilities of Linear Elastic Fracture Mechanics (LEFM) and non-LEFM methods for analysing service fatigue failures and full- and sub-scale test results. This discussion is derived primarily from the experiences of the Defence Science and Technology Group in Melbourne, Australia, and the Netherlands Aerospace Centre, Marknesse, the Netherlands.

Table of Contents

Frontmatter

Chapter 1. Historical Review

Abstract
Fatigue crack growth (FCG) analyses for metals and alloys properly began in the 1950s [1–6]. Test data [3–6] were obtained by optical measurements of the crack lengths visible on the specimen surfaces. In the same decade it was suspected [7] and demonstrated by optical fractography [8] that striations on fatigue fracture surfaces generally represented cycle-by-cycle progression of a crack.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 2. Basic Information for Aircraft FCG Failure and Lifing Analyses

Abstract
This Chapter presents some general and detailed information particularly relevant to FCG failure analyses. Three main topics are considered: (i) the importance of fatigue with respect to aircraft structural failures; (ii) fatigue nucleation and cracking; (iii) a summary of FCG lifing methods.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 3. Quantitative Fractography (QF) for FCG Analyses

Abstract
The study of fatigue fractures has a long history [116]. Macroscopic fatigue progression markings on fracture surfaces were mentioned as such by 1926 [117].
Russell Wanhill, Simon Barter, Loris Molent

Chapter 4. Aermacchi MB-326H Wing Spar (1990): Exponential FCG Analysis

Abstract
In November 1990 an RAAF Aermacchi MB-326H jet trainer, tail number A7-076, crashed into the sea off the east coast of Australia.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 5. P&W 125B Engine Bearing (1994): 2-Stage Exponential FCG Analysis

Abstract
In February 1994 the right wing engine of a Fokker 50 aircraft failed during take-off, which was aborted. This incident was caused by fatigue failure of the No. 3 bearing, which allowed the low pressure impeller to move forward, resulting in secondary damage and subsequent engine failure [134]: the engine was internally destroyed.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 6. EBA Example Lifing Assessment (2004): F/A-18 Horizontal Stabilator Spindles

Abstract
As discussed in Chap. 1, Sect. 1.2.4, the EBA is a framework for predicting the FCG lives of in-service aircraft structures subjected to relatively short and repeated blocks of VA loading sequences, i.e. load sequences representative for tactical aircraft.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 7. LCFLF Example Lifing Assessment (2004): F/A-18 Vertical Tail Attachment Stubs

Abstract
As mentioned in Chap. 6, in 1996 the DST began a unique full-scale fatigue test, FT46, of an F/A-18 aft fuselage and empennage assembly. This test article was especially acquired for testing. The test combined buffet-induced dynamic loading and manoeuvre loading at representative load frequencies, which was a formidable challenge for buffet loading [136].
Russell Wanhill, Simon Barter, Loris Molent

Chapter 8. Cubic Rule Life Prediction Examples

Abstract
As discussed in Chap. 1, Sect. 1.2.5.2, the cubic rule is a special category of the LCFLF.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 9. Fokker 100 Fuselage Test: Lap Joints Exponential FCG Analysis

Abstract
In the mid-1980s Fokker Aircraft began a full-scale fatigue test of the fuselage and wings of the F100 aircraft [140]. During the test, which ran to 126,250 simulated flights, fatigue cracking occurred along one of the pressure cabin longitudinal lap splices, see Fig. 9.1. The lap slice had been assembled by adhesive bonding and riveting, and cracking extended over several frame bays that had poor adhesive bonds.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 10. Sikorsky S-61N Rotor Blade (1974): Exponential FCGR Analysis

Abstract
In May 1974 a Sikorsky S-61N helicopter, operated by KLM Noordzee Helikopters, crashed into the North Sea owing to failure of a main rotor blade [73, 93]. Figure 10.1 shows the wreckage during recovery. The indicated blade 3 failed by fatigue and fast fracture just before the crash, whereas the other blades broke during the crash.
Russell Wanhill, Simon Barter, Loris Molent

Chapter 11. Westland Lynx Rotor Hub (1998): Progression Marking LEFM Analysis

Abstract
In November1998 a Westland Lynx helicopter, operated by the Royal Netherlands Navy (RNLN), lost a rotor blade and then the rotor head just before take-off from the RNLN base at Den Helder, the Netherlands. Figure 11.1a shows the helicopter at an earlier date with an indication of the failure location. The failure was caused by fatigue and fracture of the so-called yellow arm of the rotor hub. Figure 11.1b shows the outboard part of the fracture, which was across an elliptical plane section. The rotor hub, with GKN Westland (GKNW) designation M323, failed after 3591.9 service hours, well below the overall design safe retirement life of 5000 h minimum and 8600 h at the failure location [144].
Russell Wanhill, Simon Barter, Loris Molent

Chapter 12. Closing Remarks

Abstract
In keeping with the aims of SpringerBriefs, this book is a summary of some currently available methods for fatigue crack growth (FCG) analysis and lifing of metallic aircraft structures and components. These methods are drawn from the authors’ experiences going back, in one case, to the 1970s.
Russell Wanhill, Simon Barter, Loris Molent

Backmatter

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