Here, a new class of 2.5D angle-interlock resin matrix woven composites with a shallow straight-link architecture has been experimentally investigated. To sum up, the comprehensive effects of hole and temperature may result in accelerating the disastrous failure of composites, but there is no reference about the influence of them on the mechanical properties and failure mechanism of 2.5D resin matrix woven composites with a center hole. However, the influence of hole on the mechanical behavior of 2.5D resin matrix woven composites is still unambiguous, especially at elevated temperatures, due to the complexity of 3D-net-shaped architecture. As for the 2D resin matrix woven composites, Vieille and Taleb investigated the thermo-mechanical behaviors of 2D thermosetting-based wove composites with a circle hole, and found that the highly ductile behavior at un-ambient temperature is very effective to accommodate the overstresses near the hole 20. Furthermore, large-area delamination along with necking phenomenon was found at elevated temperatures, attributed to the softening and failure of resin matrix 31. As for the resin matrix laminated with a hole characterization, the occurrence of splitting in composites is sensitive to the mechanical properties at room temperature 30. However, experimental results indicate that hole has a remarkable impact on the crack propagation of damaged zones and the mechanical properties of laminated/2D woven composites 25– 29. For the 3D woven composites, the thermo-mechanical responses at high temperatures were rarely studied.Īpart from the thermo-mechanical performance, the fact of joining composites to other structures makes it necessary to drill composite components, which inevitably damages both fibers and matrix in the hole-edge domain 23, 24. noted that the overstresses were in the hole edge of woven composites at the temperature higher than the T g, which can be effectively accommodated by the highly ductile of resin 20. found that the resin softening at 225 ☌ can effectively mitigate the stress concentration in 2D woven composites, thereby resulting in the failure of fiber yarns 8, 22. Experimental results shown that primary load-bearing fiber yarns were rotated and straightened out just ahead of failure. Failure mechanisms in off-axis 2D woven composites at room temperature and 205 ☌ were experimentally studied by Selezneva et al. But few works are focus on the thermo-mechanical behaviors of woven composites 17– 21. Many scholars have reported the mechanical behaviors of laminated composites at room and elevated temperatures 12– 16. However, some composite structures expose to long-term temperatures in 100–200 ☌ such as aero-engine casing, which requires that resin matrix composites have a temperature-resistant capacity 7– 11. As a new category of lightweight woven composites, layer-to-layer 2.5D angle-interlock woven composites have a potential application in the field of aerospace engineering such as fan blade and aero-engine case due to the advantages over the conventional laminated composites, including through-thickness reinforcement, high damage tolerance and advanced anti-fatigue characteristic 5, 6. The application of carbon fiber reinforced resin matrix woven composites has significantly accelerated in the past few years 1– 4. Due to the primary load-bearing warp yarns and hole-edge stress concentration, obvious pull-out warp yarns emerge near the hole edge. Even at 240 ☌, there is no necking phenomenon for all the failed samples, but more broom-like damage extent is observed in the cross-section. For the open-hole samples, it is interestingly found that the strength retention rates are higher than that of samples without the hole at 180 ☌, resulting from the stress concentration accommodation and fiber-dominated failure mode. The strength retention rates at 180 ☌ and 240 ☌ are totally equal. It is noted for samples without the center hole that with the increase of temperature, the tensile stress–strain curves exhibit a linear response until that a slight nonlinearity at the end stage. Thermal property of QY8911-IV resin is investigated by DMA analysis. Failure modes are examined by scanning electron microscope (SEM). 2.5DWC) with/without a center hole are first conducted at different temperatures (20 ☌, 180 ☌ and 240 ☌). Here, tensile experiments of shallow straight-link-shaped 2.5D woven composites (abbr. The temperature-dependent mechanical behaviors of open-hole composite plates are essential for composite design and structures.
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