The fatigue of aircraft structures

Current procedures for fatigue design and for fatigue life estimation, substantiation and monitoring of aircraft structures are reviewed. Major gaps in the present state of knowledge are identified and further research directed towards filling these gaps is discussed.Brief reference is made to the major fields of basic or fundamental research connected with the fatigue of structures including, the application of fracture mechanics to the theory of crack propagation, elevated temperature behaviour of aircraft materials, atmospheric turbulence, reliability based design and aeroelastic behaviour.It is seen that with the present advances in aircraft design and utilisation the fatigue assessment of aircraft structures is an increasingly complex problem for which no general method of solution has yet been established. At present reliance is placed on extensive testing of design details and components, usually in conjunction with a full scale fatigue test, to validate the fatigue analysis and substantiate, or provide the essential data used for fatigue life monitoring. There is however a well developed trend for basic studies of the various aspects of fatigue behaviour, to find increasing application in the interpretation of experimental results for fatigue life assessment and improved methods of fatigue design.