“…This outcome suggests that the defect of symmetrical multiple delaminations may result in a decrease in the stiffness of composite [19,20]. Furthermore, the slope in stage I, II and III of Specimen B successively decreases with bending load increasing, which shows that the resistance to deformation when the structure is under stress becomes [21,22]. From a macro perspective, the catastrophic failure of specimen without defects is explosive but the instability failure of specimen containing symmetrical multiple delaminations is intermittent.…”
Section: Effects Of Delaminations On Damage Evolution Of Specimensmentioning
The study on natural aging of fiber reinforced composite, delamination damage behavior and damage pattern recognition plays a significant role in structural health monitoring of the material. In this study, acoustic emission is used to investigate damage evolution process and damage mechanisms in unidirectional glass and carbon-glass orthogonal woven fiber reinforced composites containing symmetric multiple delaminations under three point bending testing. Based on the principle of control variables, four kinds of specimens are manufactured to investigate the comparative study for the effects of delaminations, reinforced materials and fiber orientation on buckling failure behaviors and the effects of aging on mechanical properties. The results indicate that the degradation of strength and stiffness of composite can be influenced by the existence of delamination defects and natural aging condition. Both negative and positive effects can be generated by natural aging condition. Moreover, reinforced materials, porosity and fiber orientation are important factors influencing the reliability of composite. Clustering results of unidirectional fiber reinforced composites indicate interphase failure is the main damage component, moreover, the existence of symmetrical multiple delaminations will aggravate the damage of composite and make instability failure characterized by intermittency.
“…This outcome suggests that the defect of symmetrical multiple delaminations may result in a decrease in the stiffness of composite [19,20]. Furthermore, the slope in stage I, II and III of Specimen B successively decreases with bending load increasing, which shows that the resistance to deformation when the structure is under stress becomes [21,22]. From a macro perspective, the catastrophic failure of specimen without defects is explosive but the instability failure of specimen containing symmetrical multiple delaminations is intermittent.…”
Section: Effects Of Delaminations On Damage Evolution Of Specimensmentioning
The study on natural aging of fiber reinforced composite, delamination damage behavior and damage pattern recognition plays a significant role in structural health monitoring of the material. In this study, acoustic emission is used to investigate damage evolution process and damage mechanisms in unidirectional glass and carbon-glass orthogonal woven fiber reinforced composites containing symmetric multiple delaminations under three point bending testing. Based on the principle of control variables, four kinds of specimens are manufactured to investigate the comparative study for the effects of delaminations, reinforced materials and fiber orientation on buckling failure behaviors and the effects of aging on mechanical properties. The results indicate that the degradation of strength and stiffness of composite can be influenced by the existence of delamination defects and natural aging condition. Both negative and positive effects can be generated by natural aging condition. Moreover, reinforced materials, porosity and fiber orientation are important factors influencing the reliability of composite. Clustering results of unidirectional fiber reinforced composites indicate interphase failure is the main damage component, moreover, the existence of symmetrical multiple delaminations will aggravate the damage of composite and make instability failure characterized by intermittency.
“…Regardless of the random combination of needle punching rate and needle punching depth, all load–displacement curves exhibit three creeps, indicating the failure of the top TPU sheet, nonwoven interlayer, and bottom TPU sheet in order.Figure 13.(a) Schematic diagrams of laminated composites; (b) b 1 The nonwovenlayer, b 2 needle punching mechanism, and b 3 the lamination structure of the laminated composite and b 4 the needle punching machine; (c) Adhesion mechanism of LMPET fibers: c 1 melting-and-bonding diagram and c 2 thermal bonding point; (d) Image of entangled fibers of the core layer in the laminated composites (200-15) where Kevlar fibers are marked in yellow and LMPET fibers are marked in blue. 75 LMPET: low-melting-point polyester.…”
Section: Compositionmentioning
confidence: 99%
“…In addition to the fabric can be compounded with each other, the sheet and fabric can be thermally bonded to form composite materials. Lin et al 75 used Kevlar/LMPET 74 nonwoven interlayer and two TPU covers to form the laminated composites via thermal bonding which is shown in Figure 13. Results show that tensile strength and static puncture resistance mainly depend on the needle punching depth to a large extent, primarily on the tangled fiber points.…”
Section: Compositionmentioning
confidence: 99%
“…Figure 13. (a) Schematic diagrams of laminated composites; (b) b 1 The nonwovenlayer, b 2 needle punching mechanism, and b 3 the lamination structure of the laminated composite and b 4 the needle punching machine; (c) Adhesion mechanism of LMPET fibers: c 1 melting-and-bonding diagram and c 2 thermal bonding point; (d) Image of entangled fibers of the core layer in the laminated composites where Kevlar fibers are marked in yellow and LMPET fibers are marked in blue 75. LMPET: low-melting-point polyester.…”
In recent years, with the popularity of firearms and ammunition, body armor materials have undergone a great development. Body armor is commonly used to provide protection against ballistic threats, and its use has increased as people become increasingly aware of protecting their own lives. Compared with the traditional body armor materials, fabrics made of high-performance fibers are not only lightweight and convenient, but also process good protective performance. The purpose of this study is to obtain textiles with higher puncture resistance, by reviewing the progress of rapidly changing and advancing field of high-performance textiles with puncture resistance, which is introduced into four methods: shear thickening fluids (STFs), coating and impregnation, composition and structural optimization, respectively. The content of the manuscript provides a comprehensive perspective for new researchers in relevant fields for subsequent design of protective clothing.
“…On the other hand, the coating endows excellent mechanical strength and protective properties, and the chemically cross-linked organic component effectively hinders crack propagation . Furthermore, adjusting parameters such as nanofiller content, , particle size, , and ratios – in the coating solution and silk cocoon-like layer structure can substantially improve the puncture resistance of the composites. Moreover, with the advancement of industrialization and the development of the chemical field, the significance of protective materials possessing outstanding resistance to strong acids and bases cannot be overstated.…”
In extreme environments, the simultaneous requirements of puncture resistance, acid and alkali resistance, and chemical corrosion resistance are crucial for the design of safety protection materials. To address these requirements, this study employed a "scratch coating" technique, combining modified silica nanoparticles (nano F−SiO 2 ) and thermoplastic polyurethane elastomers (TPU) with aramid fabrics. This approach ensured that the composites were both soft and puncture resistant. Additionally, a simple and cost-effective spraying method was utilized to create a multifunctional coating comprising nanosilica, micron-polytetrafluoroethylene (PTFE), and fluorinated alkyl silane. Furthermore, the study investigated the effect of different lamination angles of the fabric on puncture resistance. The results demonstrated that the soft composite exhibited outstanding puncture resistance, resistance to strong acids and bases, and super-double sparsity. Notably, the maximum puncture resistance reached 515.50 N, which was 33.02 times higher than that of the pure fabric (15.61 N). Similarly, the maximum knife puncture resistance reached 247.42 N, representing a 10.77-fold increase compared to that of the pure aramid fabric (22.97 N). Notably, the obtained coating demonstrated outstanding superhydrophobicity with a water contact angle of 163.8°and a sliding angle of 3.2°. It exhibited remarkable durability when immersed in acidic or basic solutions for 120 h and exposed to outdoor conditions for more than 30 days. Importantly, the micronano coating displayed exceptional stability even when subjected to highly corrosive chemicals such as concentrated sulfuric acid (98%) and sodium hydroxide (40%) for up to 12 h. In summary, this study introduces a novel approach and method for designing flexible puncture-resistant composites with multifunctional properties. It offers valuable insights and contributes to advancements in the field of protective materials..
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