Issue 30

M. N. James, Frattura ed Integrità Strutturale, 30 (2014) 293-303; DOI: 10.3221/IGF-ESIS.30.36 302 uncracked. In summary, despite the existence of a metre long fatigue crack at the time of the inspection, the paintwork would have been uncracked and the problem would not have been detected except by detailed inspection of the joint itself. C ONCLUSIONS earning from failure remains highly relevant to achieving fracture-safe and fatigue-reliable design, particularly as the cost-driven requirements for life extension and lower design margins are, to some extent, mutually exclusive. Failure analysis therefore forms an important part of the repertoire of successful design and inspection, and should be included in the education and training of engineering students, as well as forming part of the requirement for continuing professional development of practising engineers. Further advances in achieving fatigue-reliable and fracture- safe design is, at least in part, contingent on closing the loop between failure analysis and engineering design. This is turn appears likely to require some changes to current undergraduate engineering curricula which focus more on materials as ideal homogeneous, isotropic continua, rather than the reality of polycrystalline media joined by ‘defective’ processes. In such ‘real’ media fatigue and fracture properties reflect the crystal- and micro-structure, and hence their heat treatment and manufacturing/fabrication processes, as well as their defect population, surface condition and environment. Nonetheless, the advances in engineering capability in reliable probabilistic fatigue and fracture design for complex structures, made over the last 40 years, is a tribute to the combined input from metallurgists and materials scientists, and mechanical and welding engineers. R EFERENCES [1] Hood, C., On some peculiar changes in the internal structure of iron, independent of, and subsequent to, the several processes of its manufacture, Minutes of the Proceedings (Institution of Civil Engineers), 2 Issue 1842 (January 1842) 180-181. [2] Rankine, W.J.M., On the causes of the unexpected breakage of the journals of railway axles; and on the means of preventing such accidents by observing the law of continuity in their construction, Minutes of the Proceedings (Institution of Civil Engineers), 2 Issue 1843 (January 1843) 105-107. [3] Wöhler, A., Bericht über die versuche, welche auf der Königl. Niederschlesisch-Märkischen eisenbahn mit apparaten zum messen der biegung und verdrehung von eisenbahnwägen-achsen während der fahrt, angestellt wurden, Zeitschrift für Bauwesen, 8 (1858) 641-652. [4] Wöhler, A., Ueber die festigkeits-versuche mit eisen und stahl, Zeitschrift für Bauwesen, 20 (1870) 73-106. [5] Tylecote, R.F., A History of Metallurgy, second ed., Institute of Materials, London, (1992). [6] Ewing, J.A., Humfrey, J.C.W., The fracture of metals under repeated alternations of stress, Philosophical Transactions of the Royal Society, 200 (1903) 241-266. [7] Pellini, W.S., Guidelines for fracture-safe and fatigue-reliable design of steel structures, British Welding Research Association, Cambridge (1983). [8] BS 7910:2013, Guide to methods for assessing flaws in metallic structures, third ed., British Standards Institution, London (2013). [9] Watanabe, A., Sasaki, Y., Yamasaki, M., Bending fatigue of wood: strain energy-based failure criterion and fatigue life prediction, Wood and Fiber Science, 46 (2) (2014) 1-12. [10] Withey, P.A., Fatigue failure of the De Havilland Comet 1, Engineering Failure Analysis, 2 (4) (1997) 47-154. [11] Wanhill, R.J.H., Milestone case histories in aircraft structural integrity, Comprehensive Structural Integrity, Editors-in- Chief: Milne, I., Ritchie, R.O., Karihaloo, B., Elsevier Science Ltd, (2003) 61-72. [12] Swift, T., Damage tolerance in pressurized fuselages, New Materials and Fatigue Resistant Aircraft Design, ed. D. L. Simpson, Engineering Materials Advisory Services, Warley, (1987) 1–77. [13] National Transportation Safety Board, Air Accident Report: Aloha Airlines, Flight 243, Boeing 737-200, N73711, Near Maui, Hawaii, April 28, 1988, NTSB/AAR-89/03 (1989). [14] Handbook for Damage Tolerant Design, US Air Force Structural Integrity Program, http://www.afgrow.net / (2014). [15] Brot, A., Developing strategies to combat threats against the structural integrity of aircraft, Proceedings of the 52 nd Israel Annual Conference on Aerospace Sciences, 1, 29 February - 1 March 2012, Tel-Aviv and Haifa, Israel. L