Experimental study on the effect of dents induced by impact on the fatigue life of 2024-T3 aluminum alloy plate

Local dent is one of the typical damages of the aircraft's skin panels. However, to the best of our knowledge, very few studies focus on the fatigue lives of dented aluminum plates which commonly used as aircraft skin panels. In this study, drop-weight impact tests were conducted on 2024-T3 aluminum plates to obtain spherical, conical, and U-shape dents on specimens. Subsequently, fatigue tests were performed on the dented specimens to investigate the effect of the dents on specimen's fatigue lives. It is found that all these three types of dents can obviously reduce the fatigue lives of 2024-T3 aluminum plates. Moreover, the empirical models representing relationships between residual fatigue lives and dent depths were proposed. At last, fatigue tests were carried out on specimens with both pre-cracks and dents to explore the effect of the dent on crack growth. The experimental results showed that, for the dent with medium depth relative to ultimate depth, the conical dent can aggravate the crack “macro-growth” while the spherical and U-shape dent can retard it. The observed features can provide certain references for repairing aircraft skin panels with dents.