Low‐velocity impact response and damage tolerance of hybrid biaxial/triaxial braided composite laminates

Abstract

The structural properties of braided composite laminates are significantly affected by the low‐velocity impact (LVI). In this paper, the impact resistance and damage tolerance of triaxial braid structure laminates at different positions were mainly studied. Three hybrid biaxial (B)/triaxial (T) braided composite structures of BBTT, BTTB, and TTBB were designed, and LVI test and post‐impact compression tests were carried out. The results show that the triaxial braided fabric with quasi‐isotropic on the impact side caused more significant matrix cracks along the axis yarn direction, and the matrix damage area and delamination area were larger. For triaxial braided ply with high curl levels, severe fiber fracture and relatively concentrated damage occurred first on the non‐impact side. Interestingly, triaxial braided fabrics exhibited better impact resistance in terms of mechanical response when distributed across the specimen surface. However, a global damage pattern appears at high energy levels, which seriously reduced the residual strength of the structure and showed the worst damage tolerance. The damage quantification analysis of cracks, dent depths, delamination and residual compressive strength caused by the LVI of hybrid shaft number braided laminates was carried out in this work, which provided a valuable reference for engineering failure analysis and rational structure optimization of composite laminates.

Exploration of impact response and damage mechanism of discontinuous CFRP laminates subjected to low velocity impact

“…The UC specimen had a higher impact load and displacement at the first peak compared to that of the discontinuous specimen. The displacements of the three types of specimen with an impact energy increasing to 9 J are the same before reaching the second peak; however, the displacement of the UC specimen drops sharply because of fiber breakage or the delamination of the specimen 9,30 . This implies that the discontinuous structure does not play a role in reducing the damage at the first peak, whereas it works at the second peak.…”

“…The displacements of the three types of specimen with an impact energy increasing to 9 J are the same before reaching the second peak; however, the displacement of the UC specimen drops sharply because of fiber breakage or the delamination of the specimen. 9,30 This implies that the discontinuous structure does not play a role in reducing the damage at the first peak, whereas it works at the second peak. This indicates that greater stress can be borne by the overlap structure at the same deformation, and more impact energy can be converted into the elastic potential energy, 31 which improves the impact resistance of the specimen.…”

The effect of alternating the sequence of variable‐energy repeated impact on the residual strength and damage evolution of composite laminates

“…1,2 The LVI of laminated composites has been extensively discussed in the literature. [3][4][5][6][7][8][9][10] For instance, Sun and Hallett 3 numerically and experimentally investigated the impact damage occurred in two different layups of CFRP laminates. Results revealed that the single-ply layup, [45/0/90/À 45] 4S , indicated a higher critical load and consequently a delayed delamination propagation compared with the blocked-ply laminate, [45 2 /0 2 /90 2 / À 45 2 ] 2S .…”

“…The LVI of laminated composites has been extensively discussed in the literature 3–10 . For instance, Sun and Hallett 3 numerically and experimentally investigated the impact damage occurred in two different layups of CFRP laminates.…”

An investigation into the impact resistance of bio‐inspired laminates with interlayer hybrid unidirectional/woven carbon fibers

“…However, the lower strength of laminated structures in the thickness direction makes them highly susceptible to impact load, resulting in complex failure of the internal structure caused by barely visible impact damage. Consequently, this leads to a reduction in the residual compressive strength 3,4 . Under low‐velocity impact loads, composite materials exhibit a combination of failure modes, including matrix cracking, delamination, fiber fracture, and indentation 5,6 .…”