“…Also, the distribution of the nanoparticles and interaction between the nanoparticles and filaments play a fundamental role in the determination of the impact strength characteristics of the samples C1, C2 and, mainly, C3. 31–35 Figure 5.SEM of the samples (a) standard; (b) C1; (c) C2; and (d) C3.…”
Section: Resultsmentioning
confidence: 99%
“…36–38 In the other spectra (C1, C2, and C3), the transmittance peak at 1100 cm −1 is derived from the strong and wide asymmetric and symmetrical vibration of Si–O–Si stretching (siloxane) bonds and also at 2850 and 2944 cm −1 show the stretch of C–H and CH 3 , and C–H and CH 2 , originated by the APTES silane agent and PEG dispersant. 31,33 Figure 6.FTIR of the samples (Standard, C1, C2, and C3).…”
Section: Resultsmentioning
confidence: 99%
“…Also, the distribution of the nanoparticles and interaction between the nanoparticles and filaments play a fundamental role in the determination of the impact strength characteristics of the samples C1, C2 and, mainly, C3. [31][32][33][34][35] Figure 6 shows the FTIR spectrum of the Kevlar Õ fabric samples impregnated with STF (C1, C2, and C3) and the Kevlar Õ sample non-impregnated (standard) Table 2 summarizes the main peaks obtained. The spectrum corresponding to the standard sample shows transmittance peaks at 1100 cm À1 (C-C and C-N stretch vibration), 1200 cm À1 (vibrations in the plane of C-H, N-H, and C-N), 1355 cm À1 (stretch vibrations in the plane of C-N and C-H), 1404 cm À1 (NH 2 stretch, 1550 cm À1 (bending and stretching of N-H and C-C of the aromatic ring), 1650 cm À1 (stretching vibrations of C¼O) and at 3360 cm À1 (N-H stretch) which are the vibration bands originated from the surface of the Kevlar Õ standard sample.…”
Use of colloidal silica suspensions impregnated in Kevlar® fabrics is new avant-garde of protection equipment for stab wounds and piercing objects. Kevlar® fabrics impregnated with non-Newtonian fluids have been used for protection against sharp blows, mainly due to their lightweight, good flexibility, and superior resistance properties. The aims of this investigation are to demonstrate that Kevlar® fabric impregnated with shear thickening fluids could be improved its performance through the use Aminopropyltrimethoxysilane, as well as by increasing the concentration of silica nanoparticles in its composition. Friction tests on yarns showed that Kevlar® yarns with shear thickening fluids (sample C3—25% Silica and 75%polyethylene glycol with 38% aminopropyltrimethoxysilane), presented higher strength values (10.5 N) when compared with other samples. Impact resistance tests showed that Kevlar® samples with highest concentration shear thickening fluids nanoparticles and oriented fabric layers (C3 OR) presented better performance regarding to penetration depth of stabs P1 (17 mm), S1 (18 mm) and as well as residual energy dissipation, when compared with the standard and other samples. Addition of shear thickening fluids cause reduction in the flexibility of the Kevlar® fabrics, producing sample with 42.74% less flexibility than the standard sample (C3). Adhesion tests for C3 samples exhibited more stable wettability and spreading rate, i.e., a greater adhesion of shear thickening fluids in Kevlar® fabrics than other samples due to its composition (higher concentration of nanoparticles and superior amount of silane agent). Finally, results showed that the shear thickening fluids composition as well as Kevlar® layers orientation should be used to improve the performance of Kevlar® fabrics under impact tests.
“…Also, the distribution of the nanoparticles and interaction between the nanoparticles and filaments play a fundamental role in the determination of the impact strength characteristics of the samples C1, C2 and, mainly, C3. 31–35 Figure 5.SEM of the samples (a) standard; (b) C1; (c) C2; and (d) C3.…”
Section: Resultsmentioning
confidence: 99%
“…36–38 In the other spectra (C1, C2, and C3), the transmittance peak at 1100 cm −1 is derived from the strong and wide asymmetric and symmetrical vibration of Si–O–Si stretching (siloxane) bonds and also at 2850 and 2944 cm −1 show the stretch of C–H and CH 3 , and C–H and CH 2 , originated by the APTES silane agent and PEG dispersant. 31,33 Figure 6.FTIR of the samples (Standard, C1, C2, and C3).…”
Section: Resultsmentioning
confidence: 99%
“…Also, the distribution of the nanoparticles and interaction between the nanoparticles and filaments play a fundamental role in the determination of the impact strength characteristics of the samples C1, C2 and, mainly, C3. [31][32][33][34][35] Figure 6 shows the FTIR spectrum of the Kevlar Õ fabric samples impregnated with STF (C1, C2, and C3) and the Kevlar Õ sample non-impregnated (standard) Table 2 summarizes the main peaks obtained. The spectrum corresponding to the standard sample shows transmittance peaks at 1100 cm À1 (C-C and C-N stretch vibration), 1200 cm À1 (vibrations in the plane of C-H, N-H, and C-N), 1355 cm À1 (stretch vibrations in the plane of C-N and C-H), 1404 cm À1 (NH 2 stretch, 1550 cm À1 (bending and stretching of N-H and C-C of the aromatic ring), 1650 cm À1 (stretching vibrations of C¼O) and at 3360 cm À1 (N-H stretch) which are the vibration bands originated from the surface of the Kevlar Õ standard sample.…”
Use of colloidal silica suspensions impregnated in Kevlar® fabrics is new avant-garde of protection equipment for stab wounds and piercing objects. Kevlar® fabrics impregnated with non-Newtonian fluids have been used for protection against sharp blows, mainly due to their lightweight, good flexibility, and superior resistance properties. The aims of this investigation are to demonstrate that Kevlar® fabric impregnated with shear thickening fluids could be improved its performance through the use Aminopropyltrimethoxysilane, as well as by increasing the concentration of silica nanoparticles in its composition. Friction tests on yarns showed that Kevlar® yarns with shear thickening fluids (sample C3—25% Silica and 75%polyethylene glycol with 38% aminopropyltrimethoxysilane), presented higher strength values (10.5 N) when compared with other samples. Impact resistance tests showed that Kevlar® samples with highest concentration shear thickening fluids nanoparticles and oriented fabric layers (C3 OR) presented better performance regarding to penetration depth of stabs P1 (17 mm), S1 (18 mm) and as well as residual energy dissipation, when compared with the standard and other samples. Addition of shear thickening fluids cause reduction in the flexibility of the Kevlar® fabrics, producing sample with 42.74% less flexibility than the standard sample (C3). Adhesion tests for C3 samples exhibited more stable wettability and spreading rate, i.e., a greater adhesion of shear thickening fluids in Kevlar® fabrics than other samples due to its composition (higher concentration of nanoparticles and superior amount of silane agent). Finally, results showed that the shear thickening fluids composition as well as Kevlar® layers orientation should be used to improve the performance of Kevlar® fabrics under impact tests.
“…The majority of the empirical studies are ballistic impact tests (Arora et al, 2019;Ávila et al, 2018;Khodadadi et al, 2019;Lee et al, 2003) and stab resistance (Gürgen andKuşhan, 2017b, 2017c;Xu et al, 2017). Yarn pull-out studies are also available in the public literature which is considered a metric of energy absorption during ballistic impact (Bai et al, 2019;Feng et al, 2018). The most commonly used metric in ballistic impact studies is the residual velocity.…”
Section: Impregnation Of Stf Into Woven Fabrics and Behaviour Under Imentioning
Soft armour consisting of multi-layered high-performance fabrics are a popular choice for personal protection. Extensive work done in the last few decades suggests that shear thickening fluids improve the impact resistance of woven fabrics. Shear thickening fluid–impregnated fabrics have been proven as an ideal candidate for producing comfortable, high-performance soft body armour. However, the mechanism of defeating a projectile using a shear thickening fluid–impregnated multi-layered fabric is not fully understood and can be considered as a gap in the research done on the improvement of soft armour. Even though considerable progress has been achieved on dry fabrics, limited studies have been performed on shear thickening fluid–impregnated fabrics. The knowledge of simulation of multi-layered fabric armour is not well developed. The complexity in creating the geometry of the yarns, incorporating friction between yarns and initial pre-tension between yarns due to weaving patterns make the numerical modelling a complex process. In addition, the existing knowledge in this area is widely dispersed in the published literature and requires synthesis to enhance the development of shear thickening fluid–impregnated fabrics. Therefore, this article aims to provide a comprehensive review of the current methods of modelling shear thickening fluid–impregnated fabrics with a critical analysis of the techniques used. The review is preceded by an overview of shear thickening behaviour and related mechanisms, followed by a discussion of innovative approaches in numerical modelling of fabrics. A novel state-of-the-art means of modelling shear thickening fluid–impregnated fabrics is proposed in conclusion of the review of current methods. A short case study is also presented using the proposed approach of modelling.
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