Residual stress and fatigue life in laser shock peened open hole samples

This study investigates the effects of various laser shock peening patterns on the residual stress distribution and fatigue performance of beta-solution-treated and over-aged (BSTOA) Ti–6Al–4V open hole fatigue samples. The residual stress produced by various laser shock peening patterns was measured using the contour method. Additional samples were laser peened with similar patterns and fatigue tested to establish a correlation between the residual stress distribution and fatigue performance. A description of each of the patterns is presented along with the corresponding residual stress measurements and fatigue testing results. The results clearly show that the laser shock peening pattern can have a large impact on the residual stress produced. A laser shock peening pattern with multiple concentric rings of spots around the circumference of the hole produced the most favorable residual stress distribution in the vicinity of the hole and also resulted in the best fatigue performance.

► Residual stress and fatigue life are measured in laser shock peened open hole samples.
► Residual stress depends strongly on the area where laser shock peening is applied.
► Depending on the processed area, laser shock peening either degrades or improves fatigue behavior.
► Laser shock peening open holes in a circular pattern provides a significant fatigue benefit.