Print Email Facebook Twitter Experimental study of post-buckled single-stringer composite specimens under fatigue loads with different load levels and load ratios Title Experimental study of post-buckled single-stringer composite specimens under fatigue loads with different load levels and load ratios Author Paz Mendez, J. (TU Delft Aerospace Structures & Computational Mechanics) Raimondo, A. (TU Delft Aerospace Structures & Computational Mechanics) Bisagni, C. (TU Delft Aerospace Structures & Computational Mechanics) Date 2023 Abstract This study aims at better understanding the damage tolerance of stiffened composite panels subjected to fatigue loads in the post-buckling regime. Ten single-stringer hat-stiffened specimens with an initial delamination between the skin and the stringer foot were manufactured, and then tested under quasi-static and fatigue loads in post-buckling conditions, with different load levels and load ratios. The tests were monitored with digital image correlation and an ultrasonic system, providing data on the displacements, strains, and extension of the delamination length. The quasi-static results showed that the delamination onset, when the initial delamination begins propagating, occurred at loads over twice the buckling load, while collapse occurred for values almost 20% higher than the delamination onset. During fatigue testing at load levels below the delamination onset, the specimens were able to sustain 150000 cycles and then, when tested statically after fatigue, the average load at collapse was reduced by less than 10% with respect to the quasi-static benchmark. When the maximum load during fatigue was increased to 5% over the delamination onset load, the specimens still withstood between 8000 and 16500 cycles before collapse, depending on the load ratio. It was also seen that for tests at the same load level, the specimens with high load ratio had a slower damage propagation. Subject Composite structuresDelaminationExperimental testsFatigueLoad ratioPost-buckling To reference this document use: http://resolver.tudelft.nl/uuid:0a26b436-dd97-419d-9b8b-62e2c9ff3f3e DOI https://doi.org/10.1016/j.compositesb.2023.110606 ISSN 1359-8368 Source Composites Part B: Engineering, 255 Part of collection Institutional Repository Document type journal article Rights © 2023 J. Paz Mendez, A. Raimondo, C. Bisagni Files PDF 1_s2.0_S1359836823001099_main.pdf 22.98 MB Close viewer /islandora/object/uuid:0a26b436-dd97-419d-9b8b-62e2c9ff3f3e/datastream/OBJ/view