Search Results (11)

Synthetic-materials-induced environmental burdens have shifted the focus of scientists towards sustainable packaging solutions. Three-dimensional (3D) woven fabrics offering superior mechanical durability are a promising solution to the problem. However, this area has remained unattended by researchers in the field of packaging technology. Hence this study focuses on development of warp, weft, and bidirectional interlock 3D woven fabrics for packaging applications. Aiming at mechanical durability, tensile and creep characterization have been carried out, depicting the strong influence of interlacement patterns on mechanical properties. Increasing the number of interlacements decreased tensile and creep strength, such as the lower weftwise tensile strength offered by weft interlock 3D, and vice versa for warp interlock. While elongations were found higher in interlocking directions, creep loadings carried out at 30% and 60% of breaking loads revealed unique after tensile creep behaviors. Weftwise tensile strength decreased after creep; warp interlock 3D entailed 42% decrease in tensile strength after creep. However, warpwise tensile strength was noticed to be higher for weft interlock 3D, owing to alignment of yarns during applied creep, while a decrease was noticed in elongation percentages. In a nutshell, the engineered 3D interlacements entailed successful tailoring of mechanical properties, paving a pathway towards high-strength sustainable packaging. Full article

The assessment of the dynamic mechanical performance of fiber-reinforced composites has gained importance in specific high-tech applications like aerospace and automobiles. However, three dimensional (3D) auxetic reinforcements offering viable performance have remained unexplored. Hence, this study investigates the energy absorption capabilities and high strain impact behaviors of 3D woven fabric-reinforced composites. Three different types of 3D woven reinforcements i.e., warp interlock (Wp), weft interlock (Wt), and bidirectional interlock (Bi) were developed from jute yarn, and their corresponding composites were fabricated using polycarbonate (PC) and polyvinyl butyral (PVB). Out-of-plane auxeticity was measured for reinforcements while composites were analyzed under dynamic tests. Wp exhibited the highest auxeticity with a value of −1.29, Bi showed the least auxeticity with a value of −0.31, while Wt entailed an intermediate value of −0.46 owing to variable interlacement patterns. The dynamic mechanical analysis (DMA) results revealed that composite samples developed with PC resin showed a higher storage modulus with the least tan delta values less than 0.2, while PVB-based samples exhibited higher loss modulus with tan delta values of 0.6. Split Hopkinson pressure bar (SHPB) results showed that, under 2 and 4 bar pressure tests, PVB-based composites exhibited the highest maximum load while PC-based composites exhibited the least. Warp interlock-based composites with higher auxeticity showed better energy absorption when compared with the bidirectional interlock reinforcement based (with lower auxeticity) composites that exhibited lower peak load and energy dissipation. Full article

In this study, five three-dimensional angle-interlock fabrics with different warp and weft densities were fabricated using 1000D Kevlar filaments. The Kevlar/EP composites were prepared by vacuum-assisted molding techniques. The low-velocity impact property of the composite was tested, focusing on the effects of the warp and weft densities, impact energy, impactor shape, and impactor diameter. The damage area, dent depth, and crack lengths in the warp and weft direction were used to evaluate the impact performance, and the specimens were compared with plain-weave composites with similar areal densities. The dominant failure mode of the conical impactor was fiber fracture, while the dominant failure mode of the hemispherical impactor was fiber–resin debonding. The cylindrical impactor showed only minor resin fragmentation. The residual flexural strength of the composite after impact was tested to provide insights into its mechanical properties. The study findings will provide a theoretical basis for the optimization of the design of impact-resistant structures using such materials and facilitate their engineering applications. Full article

Three-dimensional (3D) woven composites have attracted much attention in the lightweight research of protective armor due to their high specific strength and good impact resistance. However, there are still many gaps in terms of the performance and influencing factors of three-dimensional deep-angle-interlock (3DDAI) Kevlar/EP armor materials. Therefore, in order to prepare 3DDAI Kevlar/EP armor materials with excellent ballistic resistance and mechanical properties, this paper studies the bending performance of 3DDAI Kevlar/EP armor materials and the influence of the number of stacking layers, resin content, laying method, and weft density. Finally, we compare it with the traditional two-dimensional (2D) plain laminated Kevlar/EP armor material. The results showed that when the 3DDAI Kevlar/EP armor material was subjected to bending load, the upper and bottom layers of the material had a great influence on the initial stiffness and fracture strength of the material, respectively; when the material’s warp and weft density are quite different, the utilization rate of the yarn and the strength of the material are negatively affected; the fracture energy of the 3DDAI Kevlar/EP armor material prepared by the orthogonal laying method was about 20% higher than that of the 3DDAI Kevlar/EP armor material with the unidirectional layering method; and the bending performance of the 3DDAI Kevlar/EP armor material in the weft direction was better than that of the 2D plain laminated Kevlar/EP armor material, with the 3DDAI Kevlar/EP armor material having better delamination resistance. The research results will lay the foundation for structural optimization and engineering applications of such materials. Full article

The mechanism of the crack propagation in three dimensional (3D) glass-fiber warp interlock epoxy composites under fatigue loading was investigated via time-lapse micro-computed tomography (µCT) observations. Two different composite samples were manufactured by means of a resin transfer molding (RTM) process under two different constant injection pressure conditions to generate intrayarn and interyarn voids separately. Fatigue loads were applied by blocks of 10⁵ cycles and followed by µCT measurements. Regions of interest for micro tomography scans were selected based on hot spots detected by infrared thermography. After the analysis of the obtained data, it was observed that detectable cracks were generally initiated by debonding in the zone between two adjacent warp yarns and grew along their interface. Then, these cracks propagated along one of the warp yarns aligned in the loading direction while remaining in the middle of the specimen cross-section. The coalescence of the cracks and further propagation to the weakest zones were observed around and after the middle lifetime. Finally, we demonstrated the influence of the void defects at different material scales. I was found that interyarn voids have relatively little influence on the fatigue performance whereas they can, sometimes, attract and deviate cracks in the matrix zone between adjacent yarns. It was also shown that the intrayarn voids are crucial to degenerate the fatigue performance of the yarns at the micro-scale. Full article

In order to achieve an efficient ballistic protection at a low weight, it is necessary to deeply explore the energy absorption mechanisms of ballistic fabric structures. In this paper, finite element (FE) yarn-level models of the designed three-dimensional (3D) angle-interlock (AI) woven fabrics and the laminated two-dimensional (2D) plain fabrics are established. The ballistic impact responses of fabric panels with and without the interlocking Z-warp yarns during the projectile penetration are evaluated in terms of their energy absorption, deformation, and stress distribution. The Z-warps in the 3D fabrics bind different layers of wefts together and provide the panel with structural support along through-the-thickness direction. The results show that the specific energy absorption (SEA) of 3D fabrics is up to 88.1% higher than that of the 2D fabrics. The 3D fabrics has a wider range of in-plane stress dispersion, which demonstrates its structural advantages in dispersing impact stress and getting more secondary yarns involved in energy absorption. However, there is a serious local stress concentration in 2D plain woven fabrics near the impact location. The absence of Z-warps between the layers of 2D laminated fabrics leads to a premature layer by layer failure. The findings are indicative for the future design of ballistic amors. Full article

Materials used in the technical application including composite reinforcements and ballistic fabrics should show not only good mechanical performance but also better deformational behaviors. Meanwhile, three dimensional (3D) warp interlock fabrics have been widely employed in such applications to substitute the two dimensional (2D) fabrics because of their enhanced through-the-thickness performance and excellent formability. The deformational behaviors of such 3D warp interlock fabrics have been also influenced by various internal and external parameters. To understand and fill this gap, the current paper investigates the effects of the warp yarn interchange ratios inside the fabric structure on the formability behaviors of dry 3D warp interlock p-aramid fabrics. Four 3D warp interlock architecture types made with different binding and stuffer warp yarn interchange ratios were designed and manufactured. An adapted hydraulic-driven stamping bench along with hemispherical punch was utilized for better forming behavior analysis such as in-plane shear angle and its recovery, material drawing-in and its recovery, deformational depth recovery, and required stamping forces. Based on the investigation of various formability behaviors, the formability of (3D) warp interlock fabrics were greatly influenced by the binding and stuffer warp yarns interchange ratio inside the 3D warp interlock structure. For example, preform 3D-8W-0S exhibited a maximum deformational height recovery percentage of 5.1%, whereas 3D-4W-8S recorded only 0.72%. Preform 3D-8W-4S and 3D-8W-8S revealed 1.45% and 4.35% recovery percentages toward the deformational height at maximum position. Besides, sample 3D-4S-8W revealed the maximum drawing-in recovery percentage of 43.13% and 46.98% in the machine and cross direction, respectively, around the preform peripheral edges. On the contrary, samples with higher binding warp yarns as 3D-8W-0S show the maximum drawing-in recovery percentages values of 31.21% and 34.99% in the machine and cross directions respectively. Full article

Recently, three-dimensional (3D) warp interlock fabric has been involved in composite reinforcement and soft ballistic material due to its great moldability, improved impact energy-absorbing capacity, and good intra-ply resistance to delamination behaviors. However, understanding the effects of different parameters of the fabric on its mechanical behavior is necessary before the final application. The fabric architecture and its internal yarn composition are among the common influencing parameters. The current research aims to explore the effects of the warp yarn interchange ratio in the 3D warp interlock para-aramid architecture on its mechanical behavior. Thus, four 3D warp interlock variants with different warp (binding and stuffer) yarn ratios but similar architecture and structural characteristics were engineered and manufactured. Tensile and flexural rigidity mechanical tests were carried out at macro- and meso-scale according to standard EN ISO 13 934-1 and nonwoven bending length (WSP 90.5(05)), respectively. Based on the results, the warp yarn interchange ratio in the structure revealed strong influences on the tensile properties of the fabric at both the yarn and final fabric stages. Moreover, the bending stiffness of the different structures showed significant variation in both the warp and weft directions. Thus, the interchange rations of stuffer and binding warp yarn inside the 3D warp interlock fabric were found to be very key in optimizing the mechanical performance of the fabric for final applications. Full article

This paper investigates the effects of warp yarns ratios on the ballistic performances of three-dimensional (3D) warp interlock p-aramid fabrics. Four 3D warp interlock variants with different binding and stuffer warp yarns ratios were designed and developed. Except for warp yarns ratios, similar fabric parameters and manufacturing conditions were considered. Two-dimensional (2D) woven fabric having similar material characteristics and recommended for female seamless soft body armor are also considered for comparisons. Five ballistic panels, one from 2D plain weave fabric and the rest four from the other 3D warp interlock variants were prepared in a non-angled layer alignment and non-stitched but bust-shaped molded form. The ballistic test is carried out according to NIJ (National Institute of Justice) standard-level IIIA. Back Face Signature (BFS) was then modeled and measured to compute both trauma and panels’ energy-absorbing capability. The result showed significant ballistic improvement in the 3D warp interlock variant with optimum warp yarns ratios over traditional 2D plain weave fabrics. 3D warp interlock fabric panel made with 66.6% binding and 33.3% stuffer warp yarn ratio revealed both lower BFS depth and higher energy absorbing capacity (%) than other panels made of 2D plain weave and 3D warp interlock fabric variants. Full article

Multiscale characterization of the textile preform made of natural fibers is an indispensable way to understand and assess the mechanical properties and behavior of composite. In this study, a multiscale experimental characterization is performed on three-dimensional (3D) warp interlock woven fabrics made of flax fiber on the fiber (micro), roving (meso), and fabric (macro) scales. The mechanical tensile properties of the flax fiber were determined by using the impregnated fiber bundle test. The effect of the twist was considered in the back-calculation of the fiber stiffness to reveal the calculation limits of the rule of mixture. Tensile tests on dry rovings were carried out while considering different twist levels to determine the optimal amount of twist required to weave the flax roving into a 3D warp interlock. Finally, at fabric-scale, six different 3D warp interlock architectures were woven to understand the role of the architecture of binding rovings on the mechanical properties of the dry 3D fabric. The results reveal the importance of considering the properties of the fiber and roving at these scales to determine the more adequate raw material for weaving. Further, the characterization of the 3D woven structures shows the preponderant role of the binding roving on their structural and mechanical properties. Full article

Composite industry has long been seeking practical solutions to boost laminate through-thickness strengths and interlaminar shear strengths (ILSS), so that composite primary structures, such as stiffeners, can bear higher complex loadings and be more delamination resistant. Three dimensional (3D) woven fabrics were normally employed to render higher transverse and shear strengths, but the difficulty and high expense in producing such fabrics make it a hard choice. Based on a novel idea that the warp yarns that interlock layers of the weft yarns might provide adequate fiber crimps that would allow the interlaminar shear or radial stresses to be transferred and borne by the fibers, rather than by the relatively weaker matrix resin, thus improving the transverse strengths, this work provided a two point five dimensional (2.5D) approach as a practical solution, and demonstrated the superior transverse performances of an economical 2.5D shallow-bend woven fabric (2.5DSBW) epoxy composites, over the conventional two dimensional (2D) laminates and the costly 3D counterpart composites. This approach also produced a potential candidate to fabricate high performance stiffeners, as shown by the test results of L-beams which are common structural components of any stiffeners. This study also discovered that an alternative structure, namely a 2.5D shallow-straight woven fabric (2.5DSSW), did not show any advantages over the two control structures, which were a 2D plain weave (2DPW) and a 3D orthogonal woven fabric (3DOW) made out of the same carbon fibers. Composites of these structures in this study were conveniently fabricated using a vacuum-assisted resin infusion process (VARI). The L-beams were tested using a custom-made test fixture. The strain distribution and failure mode analysis of these beams were conducted using Digital Image Correlation (DIC) and X-ray Computed Tomography Scanning (CT). The results demonstrated that the structures containing Z-yarns or having high yarn crimps or waviness, such as in cases of 3DOW and 2.5DSBW, respectively, were shown to withstand high loadings and to resist delamination, favorable for the applications of high-performance structural composites. Full article