Abstract:A simple lab‐scale weaving method was used to produce multidirectional fiber preforms to improve the delamination resistance and damage tolerance of composites. Mechanical properties measured in this study included short‐beam shear strength and damage tolerance of 2‐D and 3‐D woven composites. The constituents of fiber and matrix in these composites are Kevlar‐29 (Du Pont) and Epon 828 (Shell Chemical Co.) epoxy. Attention was directed to the differentiation of deformation and failure mechanisms in these compo… Show more
“…To address the issue of impact performance in composite laminates, novel material systems and manufacturing processes have been proposed and studied over several decades—for example, matrix‐toughening routes via nano‐, micro‐ and/or macro‐scale mechanisms, fiber‐architectures via different textile preforms, and/or through‐thickness reinforcements such as z‐pinning and tufting, etc . While most of these novel materials and processes could offer opportunities to enhance impact performance, it is important to develop cost‐effective approaches—by exploring low cost raw materials and manufacturing processes—as the usage of advanced composites has recently seen a significant growth in several engineering applications.…”
Advanced composites are widely used in primary and secondary structural applications, for example, aerospace, automotive, marine, and renewable energy sectors. But it is well recognized that the impact resistance and damage tolerance of composite laminates are in general poor, which is a major challenge for optimizing structural designs. In this regard, an experimental study is conducted for enhancing the damage tolerance of 2D woven composite laminates by exploring yarn‐level fiber hybridization. Hybrid yarns are produced by combing high‐strength fibers, that is, S‐glass, and high‐toughness fibers, that is, polypropylene [PP], and using commingling and core‐wrapping processes. Using the hybrid yarns, 2D fabrics, that is, with 5H satin, 2/2 twill, and 2/2 basket architectures, are weaved, and subsequently hybrid S‐glass/PP/epoxy laminates are manufactured via vacuum assisted resin infusion. The low velocity impact response and energy absorption of the hybrid laminates are investigated by drop‐weight impact tests at different energy levels, that is, 15 J, 25 J, 35 J, and 50 J. The damage tolerance is studied by compression‐after‐impact (CAI) tests, measuring the residual compressive strength of the damaged laminates. Furthermore, the failure modes are investigated using scanning electron microscopy for identifying damage mechanisms in the hybrid laminates after the impact and CAI tests. The impact response and damage tolerance of the 5H satin, 2/2 twill, and 2/2 basket fabric laminates are compared with that of noncrimp‐fabric laminates produced with (ie, S‐glass/PP yarns) and without (ie, S‐glass yarns) yarn‐level hybridization. It is shown that yarn‐level hybridization and fiber architecture significantly affect the impact behavior and damage tolerance of the 2D woven S‐glass/PP/epoxy hybrid laminates investigated. The microscopy studies show that intra‐yarn, inter‐yarn, inter‐lamina failure mechanisms can in general be introduced by combining yarn‐level fiber hybridization and fiber architecture for modifying failure and energy dissipation mechanisms under low velocity impact and hence the damage tolerance of composite laminates.
“…To address the issue of impact performance in composite laminates, novel material systems and manufacturing processes have been proposed and studied over several decades—for example, matrix‐toughening routes via nano‐, micro‐ and/or macro‐scale mechanisms, fiber‐architectures via different textile preforms, and/or through‐thickness reinforcements such as z‐pinning and tufting, etc . While most of these novel materials and processes could offer opportunities to enhance impact performance, it is important to develop cost‐effective approaches—by exploring low cost raw materials and manufacturing processes—as the usage of advanced composites has recently seen a significant growth in several engineering applications.…”
Advanced composites are widely used in primary and secondary structural applications, for example, aerospace, automotive, marine, and renewable energy sectors. But it is well recognized that the impact resistance and damage tolerance of composite laminates are in general poor, which is a major challenge for optimizing structural designs. In this regard, an experimental study is conducted for enhancing the damage tolerance of 2D woven composite laminates by exploring yarn‐level fiber hybridization. Hybrid yarns are produced by combing high‐strength fibers, that is, S‐glass, and high‐toughness fibers, that is, polypropylene [PP], and using commingling and core‐wrapping processes. Using the hybrid yarns, 2D fabrics, that is, with 5H satin, 2/2 twill, and 2/2 basket architectures, are weaved, and subsequently hybrid S‐glass/PP/epoxy laminates are manufactured via vacuum assisted resin infusion. The low velocity impact response and energy absorption of the hybrid laminates are investigated by drop‐weight impact tests at different energy levels, that is, 15 J, 25 J, 35 J, and 50 J. The damage tolerance is studied by compression‐after‐impact (CAI) tests, measuring the residual compressive strength of the damaged laminates. Furthermore, the failure modes are investigated using scanning electron microscopy for identifying damage mechanisms in the hybrid laminates after the impact and CAI tests. The impact response and damage tolerance of the 5H satin, 2/2 twill, and 2/2 basket fabric laminates are compared with that of noncrimp‐fabric laminates produced with (ie, S‐glass/PP yarns) and without (ie, S‐glass yarns) yarn‐level hybridization. It is shown that yarn‐level hybridization and fiber architecture significantly affect the impact behavior and damage tolerance of the 2D woven S‐glass/PP/epoxy hybrid laminates investigated. The microscopy studies show that intra‐yarn, inter‐yarn, inter‐lamina failure mechanisms can in general be introduced by combining yarn‐level fiber hybridization and fiber architecture for modifying failure and energy dissipation mechanisms under low velocity impact and hence the damage tolerance of composite laminates.
“…It is assumed that the resin is an elastic-plastic solid obeying the J2-isotropic hardening plasticity theory with an associated flow rule and a von Mises yield criterion. 26 Figure 4.Finite element analyses model: (a) low velocity impact model; (b) compression model.…”
This paper reports impact and compression behaviours of three-dimensional angle interlock woven composites after the thermal ageing degradation in both experimental and finite element analyses. The composite coupons have been aged in atmospheric environment for 4, 8, 16 and 32 days at 180℃. Barely visible impact damage was induced by low velocity impact test and the residual strength was evaluated by following compression test. The results show a substantial decline in compression after impact properties after thermal ageing. After aging at 180℃ for 32 days, the compression after impact stress and modulus retention rates of three-dimensional woven composites are 59% and 82.2%, respectively. Such degradation is attributed to interface damage and matrix degradation. The fracture morphologies observed by microscopy revealed that the failure of the original specimen was dominated by matrix crack, while for long time aged specimens interface degradation became main damage mechanism. The numerical study was used to unveil the influence of matrix crack and interface degradation on failure developments of composites. The results indicate a variation from a brittle failure mode to a progressive failure model after long time ageing.
“…2D and 3D woven fabrics) are widely employed to explore different fibre interlacements for achieving desired architectures [6,7]. A significant amount of research conducted on textile composite laminates studying their in-plance mechanical properties, impact behaviour and damage tolerance has shown that superior impact damage tolerance and resistance compared to uni-directional pre-preg based laminates can be achieved [8][9][10][11][12]. Moreover, in recent years, several approaches to introduce through-thickness reinforcements are explored to further enhance damage tolerance in textile laminates, e.g.…”
Towards balancing in-plane mechanical properties and impact damage tolerance of composite laminates using quasi-UD woven fabrics with hybrid warp yarns. Composite Structures, 225, [111083].
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