The influence of cyclic stress intensity threshold on fatigue life scatter
Source abstract
Abstract
Abstract Understanding factors that contribute to scatter in fatigue lives of metallic structures (particularly airframes) subjected to identical spectrum is critical to maintaining safety and optimising designs. This paper first briefly discusses the sources of scatter, and then concentrates on the effect of variations in the “cyclic stress intensity threshold” (ΔKthr) on fatigue crack growth. It shows that a version of the NASGRO equation can be used to account for the crack growth scatter seen in a number of classical fatigue experiments by accounting for variations in ΔKthr. This is an important outcome for safety and is particularly useful when considering lead cracks for which ΔKthr is small (approaching zero) as these cracks appear to commence growing soon after introduction into service.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Fatigue and fracture mechanics · Probabilistic and Robust Engineering Design · Structural Health Monitoring Techniques
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (57)
Show source-provided references
1. Design and airworthiness requirements for service aircraft volume 1 – aeroplanes. Defence Standard 00-970, issue 1; December 1983.
2. Interpreting fatigue test results using a probabilistic fracture approach10.1016/j.ijfatigue.2005.01.006 ↗
3. Alternative methods for derivation of safe life limits for a 7050-T7451 aluminium alloy structure10.1016/j.ijfatigue.2014.12.012 ↗
4. Review of fatigue monitoring of agile military aircraft10.1046/j.1460-2695.2000.00330.x ↗
5. Calculating crack growth from small discontinuities in 7050-T7451 under combat aircraft spectra10.1016/j.ijfatigue.2013.06.009 ↗
6. Wanhill RJH, Barter SA, Hattenberg T, Huls RA, Ubels RC, Bos MJ. Fractography-assisted observations on fatigue thresholds in an aerospace aluminium alloy. NLR-TP-2009-596; December 2010.
7. Wanhill RJH. Durability analysis using short and long fatigue crack growth data. In: Proc int conf aircraft damage assessment and repair, Melbourne, 26–28 Aug 1991; 1991. p. 100–4.
8. The lead crack fatigue lifing framework10.1016/j.ijfatigue.2010.09.009 ↗
9. Molent L, Barter SA, Wanhill RJH. The lead crack fatigue lifing framework. DSTO-RR-0353, 2010, Melbourne, Australia.10.1016/j.ijfatigue.2010.09.009 ↗
10. Molent · 2005
11. Molent · 2012
12. Characterisation of equivalent initial flaw sizes in 7050 aluminium alloy10.1111/j.1460-2695.2006.01050.x ↗
13. Molent · 2006
14. A review of equivalent pre-crack sizes in aluminium alloy 7050-T745110.1111/ffe.12214 ↗
15. The equivalence of EPS and EIFS based on the same crack growth life data10.1016/j.ijfatigue.2015.05.009 ↗
16. An experimental evaluation of fatigue crack growth10.1016/j.engfailanal.2004.04.002 ↗
17. A comparison of crack growth behaviour in several full-scale airframe fatigue tests10.1016/j.ijfatigue.2006.09.015 ↗
18. Fatigue crack growth and damage tolerance10.1111/ffe.12155 ↗
19. Fatigue crack growth in a diverse range of materials10.1016/j.ijfatigue.2012.01.004 ↗
20. Wanhill · 2009
21. A study of nucleation and fatigue behavior of an aerospace aluminum alloy 2024-T310.1016/j.ijfatigue.2004.06.010 ↗
22. Schijve J. Fatigue life until small cracks in aircraft structures: durability and damage tolerance, advanced structural integrity methods for airframe durability and damage tolerance. In: C.E. Harris, editor. Proceedings FAA/NASA international symposium, Hampton, 1994. NASA Conference Publication 3274. p. 665–81.
23. Rudd · 1977
24. Macheret Y, Teichman J. Improved estimation of aircraft probability of failure. IEEE AC paper #1129, Version 3, USA; 2007.10.1109/AERO.2008.4526614 ↗
25. What is fatigue damage? A view point from the observation of low cycle fatigue process10.1016/j.ijfatigue.2004.10.009 ↗
26. Estimating the statistical properties of crack growth for small cracks10.1016/0013-7944(83)90139-X ↗
27. Berens · 1991
28. Crack growth from naturally occurring material discontinuities in operational aircraft
29. Prediction of fatigue life in aluminium alloy (AA7050-T7451) structures in the presence of multiple artificial short cracks10.1016/j.tafmec.2015.06.001 ↗
30. Application of the Hartman–Schijve equation to represent Mode I and Mode II fatigue delamination growth in composites10.1016/j.compstruct.2011.11.030 ↗
31. Implications of the lead crack philosophy and the role of short cracks in combat aircraft10.1016/j.engfailanal.2012.10.023 ↗
32. Virkler DA, Hillberry BM, Goel PK. The statistical nature of fatigue crack propagation. Technical report AFFDL-TR-78-43, 1978. Ohio, USA: Air Force Wright Aeronautical Laboratory.
33. Berens AP, Gallagher JP, Hovey PW. Statistics of crack growth. In: Proc structural reliability and damage tolerance symposium of the 9th U.S. national congress of applied mechanics, Cornell University, Jun 21–25, 1982.
34. Mode I, II and mixed mode I/II delamination growth in composites10.1016/j.compstruct.2013.12.009 ↗
35. Jones R, Mujtaba A, Kinloch AJ, Brunner AJ, Stelzer S. Thoughts on accounting for the scatter seen in delamination growth. In: Proceedings 16th Australian aerospace congress, 23–24 February 2015, Melbourne, Australia; 2015.
36. Fatigue crack growth in nano-composites10.1016/j.compstruct.2012.09.050 ↗
37. A convenient way to represent fatigue crack growth in structural adhesives10.1111/ffe.12241 ↗
38. Statistical aspects of some fatigue crack growth data10.1016/j.engfracmech.2006.08.019 ↗
39. Schijve J, de Rijk P. The fatigue crack propagation in 2024-T3 Alclad sheet materials from seven different manufacturers. National Aerospace Laboratory Report NLR M2162. Amsterdam, The Netherlands; 1966.
40. Oldersma A, Wanhill RJH. Variability of fatigue crack growth properties for 2024-T3 aluminium alloy. NLR TP 96038. Amsterdam, The Netherlands; 1996.
41. Newman JC, Wu XR, Venneri SL, Li CG. Small-crack effects in high-strength aluminium alloys. NASA Reference Publication 1309; May 1994.
42. Small crack growth and fatigue life predictions for high strength aluminium alloys. Part II: crack closure and fatigue analyses10.1046/j.1460-2695.2000.00242.x ↗
43. Donald K. An evaluation of the crack-compliance method for determining the stress intensity resulting from residual stress. In: Lados D, editor. Proceedings integrative materials design: performance and sustainability: advances in Integrated Computational Materials Engineering (ICME) & residual stress considerations in design, The Minerals, Metals and Materials Society, TMS/ASM: Mechanical Behavior of Materials Committee, Worcester Polytechnic Institute; 2012.
44. Iyyer NS, Kwon YS, Phan N. P-3C crack growth life predictions under spectrum loading. In: Proc international committee on aeronautic fatigue, Lucerne, Switzerland, May 5–9, 2003; 2003.
45. Aircraft life management using crack initiation and crack growth models – P-3C Aircraft experience10.1016/j.ijfatigue.2007.03.017 ↗
46. Experimentally derived crack growth models for different stress concentration factors10.1016/j.ijfatigue.2008.02.008 ↗
47. A study into the interaction of intergranular cracking and cracking at a fastener hole10.1007/s11012-013-9849-x ↗
48. Lo M, Jones R, Peng D, Bowler A, Edwards D. Fatigue crack growth from environmentally induced damage in 7075 alloy. In: Proceedings 28th ICAF symposium – Helsinki, 3rd–5th, June 2015.
49. Propagation of short fatigue cracks10.1179/imr.1984.29.1.445 ↗
50. An analysis of the growth of short fatigue cracks10.1016/0013-7944(91)90151-P ↗
51. Prediction of the behaviour of small fatigue cracks10.1016/j.msea.2006.09.084 ↗
52. Stress ratio effects on small fatigue crack growth in Ti–6Al–4V10.1016/j.ijfatigue.2011.11.004 ↗
53. An analysis of crack tip shielding in aluminium alloy 2124: a comparison of large, small through-crack and surface fatigue cracks10.1111/j.1460-2695.1987.tb00485.x ↗
54. Kondo Y, Endo M, McEvily AJ. Short crack growth behavior and its relation to notch sensitivity and VHCF. In: Proceeding 17th European conference on fracture, 2nd–5th September, Brno, Czech Republic; 2008. p. 159–67.
55. Mixed-mode, high-cycle fatigue-crack growth thresholds in Ti–6Al–4V I. A comparison of large- and short-crack behaviour10.1016/S0013-7944(00)00046-1 ↗
56. Speaker · 1988
57. The comparison of complex load sequences tested at several stress levels by fractographic examination10.1016/j.engfailanal.2004.09.007 ↗