A major challenge for the aircraft industry in the future will be the development of effective strategies for maintaining and extending the service life of aging aircraft fleet. In this context, residual-stress-based approaches for extending the fatigue life of aircraft components are believed to have great potential for providing cost-effective solutions. This paper reviews residual-stress-based life extension techniques and published work on the use of these techniques in aerospace applications. The techniques reviewed include cold expansion, shot peening, laser shock peening, deep rolling, and heating. Comparisons of the various techniques with regard to current applications and limitations are given.

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Laser Shock Peening allows the introduction of deep compressive residual stresses into metallic components. It is applicable to most metal alloys used for aerospace applications. The method is relatively expensive in application, and therefore development studies often rely heavily on Finite Element Modelling to simulate the entire process, with a high computational cost. A different approach has been used recently, the so-called eigenstrain approach. The present study looks at the feasibility of applying the eigenstrain method for prediction of the residual stress in a sample that contains curved surface features. The eigenstrain is determined from a simple geometry sample, and applied to the more complex geometry to predict the residual stress after Laser Shock Peening. In particular the prediction of residual stress at a curved edge, and for different values of material thickness, have been studied. The research has demonstrated that the eigenstrain approach gives promising results in predicting residual stresses when both the thickness and the geometry of the peened surface is altered.