From Laser Shock Peening: Performance and Process Simulation
2.7 Effects on Mechanical Properties
Many materials display pronounced improvements in fatigue life with LSP. The beneficial effects of LSP may originate from surface compressive stresses in the large affected depth and improved surface quality, which delay the development of fatigue cracking. Investigations of several different aspects of the fatigue behaviours, such as fatigue life, fatigue strength and fretting fatigue, have been reported.
2.7.1 Fatigue Life and Strength
Investigations of aluminium alloys, steels and titanium alloys have shown that LSP can increase the fatigue strength of these materials. The initial research work focused on the effect of LSP on the fatigue crack growth of pre-existing cracks, using different laser spot shapes on the pre-cracks (Clauer et al., 1983). The two different laser spot configurations were applied around a hole in a 2024 T3 aluminium alloy specimen, shown in Fig. 2.15(a). The specimen had a cantered hole with small starter notches machined into its sides. The region around the hole was shocked simultaneously on both sides using split laser beams. One laser spot configuration used a solid spot to treat the entire region around the hole, while the other laser spot used only an annular-shaped area around the hole and notched region. The fatigue life increases for both laser spot configurations, shown in Fig. 2.15(b), and the laser-peened 2024 T3 specimens with the solid laser spot had a fatigue life about 40 times longer than the non-shocked ones, whereas those with the annular laser spot had a life about three times longer than...
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2.8 Applications of Laser Shock Peening Since the development of LSP, a strong interest in its commercialisation can be seen by the number of patents issued on this process. The first two key...
7.1 Introduction This chapter presents two-dimensional (2D) and three-dimensional (3D) dynamic finite element (FE) simulations for the residual stress distribution induced by single and multiple LSP...
6.1 Introduction For a thick alloy component, LSP can be performed individually or simultaneously on any part of a surface. However, for a thin section, a laser pulse must be split, impacting...
The effect of various surface treatments on the fretting fatigue and joint fatigue performance of a 7xxx series aluminum alloy was investigated with the objective to reduce the nucleation and growth...
1.1 Laser Shock Peening Laser shock peening (LSP) is an innovative surface treatment technique, which is successfully applied to improve fatigue performance of metallic components. After the...
