2D Plain Weave Research Articles

Exploring the effects of angle of incidence on stabbing resistance in advanced protective textiles: Novel experimental framework and analysis

Despite numerous research investigations to understand the influences of various structural parameters, to the authors' knowledge, no research has been the effect of different angles of incidence on stab response and performance of different types of protective textiles. Three distinct structures of 3D woven textiles and 2D plain weave fabric made with similar high-performance fiber and areal density were designed and manufactured to be tested. Two samples, one composed of a single and the other of 4-panel layers, from each fabric type structure, were prepared, and tested against stabbing at [0°], [22.5°], and [45°] angle of incidence. A new stabbing experimental setup that entertained testing of the specimens at various angles of incidence was engineered and utilized. The stabbing bench is also equipped with magnetic sensors and a UK Home Office Scientific Development Branch (HOSDB)/P1/B sharpness engineered knives to measure the impact velocity and exerted impact energy respectively. A silicon compound was utilized to imprint the Back Face Signature (BFS) on the backing material after every specimen test. Each silicon print was then scanned, digitized, and precisely measured to evaluate the stab response and performance of the specimen based on different performance variables, including Depth of Trauma (DOT), Depth of Penetration (DOP), and Length of Penetration (LOP). Besides, the post-impact surface failure modes of the fabrics were also measured using Image software and analyzed at the microscale level. The results show stab angle of incidence greatly influences the stab response and performance of protective textiles. The outcome of the study could provide not only valuable insights into understanding the stab response and capabilities of protective textiles under different angle of incidence, but also provide valuable information for protective textile manufacturer, armor developer and stab testing and standardizing organizations to consider the angle of incidence while developing, testing, optimizing, and using protective textiles in various applications.

Research on the upper limit of constant strain rates and dynamic fracture behavior for hybrid woven composite

Based on the analysis of stress wave propagation at both ends of the specimen, a formula for the upper limit of the constant strain rate is derived. The upper limit of constant strain rate is applicable to all the ratios of wave impedance, providing a broader applicability. The in-plane dynamic compressive behavior was obtained for 2D plain weave carbon/aramid hybrid composites at strain rates ranging from 195 to 790 s−1. The results validate the prediction of the upper limit of the constant strain rate. The strength exhibited sensitive to strain rate. A nonlinear constitutive model described the dynamic constitutive relationship effectively under different strain rates. The distribution of delamination failure significantly influenced the final failure shape of the specimens. Microscopic observations indicated that carbon fiber yarns and aramid fiber yarns exhibited different fracture modes.

Effect of Z-binding depths on the ballistic performance of 3D woven through-the-thickness angle-interlock fabrics in a multiply system

Lightweight armor with excellent protection against ballistic impacts are pursued by researchers worldwide. This paper systematically investigates the effect of the Z-binding depths on the ballistic performance and failure mechanisms of para-aramid 3D fabrics. Two types of 3D woven through-the-thickness angle-interlock fabrics were designed and fabricated in comparison to the 2D plain weave fabric. The ballistic tests and finite element simulation analyses were carried out based on a similar areal density of 5.2 kg/m2 by layering up the fabrics. According to the experimental results, the variability and cumulative probability of penetration of the 20-P are higher than that of the 3D fabric systems, resulting in a 2.5% higher ballistic limit V50 of 8-5 TA than 20-P. Fabric plies failed abruptly in the 2D system, while the 3D system showed a progressive failure mode. The Z-warps, configure through the thickness of the fabric, result in the projectile tumbling and deviating from its original direction. A larger binding depth can help to prolong the defending process, which will mobilize more yarns to resist the projectile impact. The back-face deformation is well constrained by the 3D fabrics. Due to the fact that the designed 3D woven fabrics are more moldable than the plain weave, it could be potential candidates for the engineering design of female bullet-proof vest interlining.

Experimental investigation on interlaminar and in-plane shear damage evolution of 2D C/SiC composites using acoustic emission and X-ray computed microtomography

Carbon fiber-reinforced silicon carbide composites (C/SiC) are widely used in lightweight aerospace structures for thermal protection due to its excellent mechanical properties. The low interfacial shear strength of the composites decreases its performance and limits its application. To investigate the shearing performance of C/SiC composite, interlaminar shear and in-plane shear tests were conducted. Real-time X-ray micro-computed tomography (XCT) non-destructive testing technology is an effective method for damage analysis of composite materials. The damage mechanisms of 2D plain weave C/SiC composites prepared by chemical vapor infiltration process under interlaminar shear loading are investigated using the combination of XCT and acoustic emission detection system. The in-situ XCT results reveal the damage visualization mechanisms of the composites and the damage evolution process including matrix damage, interfacial debonding and fiber fracture. The failure mechanisms and morphology of the shear effect for 2D plain weave C/SiC were analysed.

A non-linear material model for progressive damage analysis of woven composites using a conformal meshing framework

A progressive damage model is presented to investigate the damage and failure behaviors of woven composites. The conformal finite element mesh for the woven composites, used for this analysis, is generated using fabric micro-geometry from DFCA (Digital Element Approach (DEA) Fabric and Composite Analyzer, Kansas State University). The mesh generation strategy is discussed briefly – it does not make any idealized assumptions about yarn geometry and thus can be used for any woven composite micro-geometry. The woven composite domain consists of homogeneous and transversely isotropic yarns, and the surrounding homogeneous isotropic matrix. A recursive stiffness reduction method that allows for combined failure modes is employed to model progressive damage behavior. Two different fabric micro-geometries are studied: a 2D plain-weave laminate and a 3D orthogonal-weave unit cell. To support the validity of the proposed model, numerical results for the mechanical behavior of the two cases are discussed and compared with numerical predictions in literature and available experimental data.

Evaluating and Minimizing Induced Microbending Losses in Optical Fiber Sensors Embedded Into Glass-Fiber Composites

Conventional silica optical fibers can be embedded into composite structures or packaging to provide structural monitoring capabilities. In this paper, the microbending optical losses induced by the packaging of a sensing optical fiber into a sandwiched glass-fiber reinforced structure are investigated experimentally and by simulations. Results show that the positioning of the optical fiber within a plain-weave glass fiber-reinforced structure has a critical effect on microbending optical losses due to potentially induced microdeformations of the optical fiber's cylindrical shape. Similar analysis is also carried out with the use of a 1D glass-fiber layer packaging, demonstrating lower residual microbending losses after manufacturing. By the proper positioning of an optical fiber containing a series of wavelength-multiplexed fiber Bragg grating (FBG) sensors over a 2D plain-weave glass fabric, a 10-fold improvement in the induced optical losses is demonstrated, increasing the optical power that reaches the interrogating unit and allowing the monitoring of hundreds of meters over glass-fiber structures. Although all the analysis is focused and verified using a series of FBG sensors, the results and conclusions related to the induced microbending losses are also valid and useful for distributed optical fiber sensing approaches.

Microscopic geometrical structure analysis of 2D and 2.5D fabrics based on a simple predictive model

The braided structure has a great influence on the properties of composites, and it is of great significance to predict and design the microscopic geometrical structure of fabric. In this paper, a simple model for predicting the yarn morphologies in 2D plain weave fabric and 2.5D shallow-cross bending fabric is established. Compared with the test results, this predictive model has relatively high prediction accuracy and the influences of warp/weft density and yarn fineness on the maximum pore volume in the fabric are analyzed in detail. Based on this model, assume the yarn fineness and warp density is 3 K and 3/cm, respectively, when the weft density increases from 2/cm to 9/cm, and the volume fraction increases from 15% to 35%, the maximum pore volume in the 2D fabric decreases from 2.69 mm3 to 0.195 mm3, compared with that in the 2.5D fabric decreases from 2.67 mm3 to 0.125 mm3. At the same volume fraction, the lower the yarn fineness, the smaller the maximum pore volume in 2D and 2.5D fabrics. In addition, when the sum of the warp and weft yarn densities is a certain value, the maximum pore volumes in 2D and 2.5D fabrics decrease as the weft yarn densities increases. Conversely, as the warp density increases, the maximum pore volumes increase.

Multiscale temperature-dependent ceramic matrix composite damage model with thermal residual stresses and manufacturing-induced damage

This work presents a multiscale thermomechanical simulation framework to capture the temperature-dependent damage behavior of woven ceramic matrix composites (CMCs). The framework consists of cooldown simulations, which capture a realistic material initial state, and subsequent mechanical loading simulations to capture temperature-dependent nonlinear stress–strain behavior. The cooldown simulations result in a realistic material initial state with thermal residual stresses and damage hotspots that occur due to constituent property mismatch and post-manufacturing cooldown. A fracture mechanics-informed thermomechanical progressive damage model is extended to capture the manufacturing-induced damage that occurs because of the high thermal residual stresses and to simulate the mechanical response of two-dimensional (2D) plain weave carbon (C) fiber, silicon carbide (SiC) matrix (C/SiC) CMCs at temperatures ranging from room temperature (RT) to 1200 °C. A combination of temperature-dependent material properties and damage model parameters are included in the model to simulate the effects of temperature on deformation and damage behavior. Model calibration was conducted using quasi-static tensile experimental data from the literature for RT, 700 °C, and 1200 °C and the nonlinear, temperature-dependent predictive capabilities of the reformulated model are demonstrated for 1000 °C. The model is also applied to simulate the temperature-dependent thermomechanical response of a 2D woven five harness satin (5HS) SiC/SiC CMC at RT and 1200 °C and shows excellent agreement with experiments.

Effect of Unit-Cell Size on the Barely Visible Impact Damage in Woven Composites

The effect of the weaving architecture and the z-binding yarns, for 2D and 3D woven composites on the low-velocity impact resistance of carbon fibre reinforced composites, is investigated and benchmarked against noncrimp fabric (NCF). Four architectures, namely: NCF, 2D plain weave (2D-PW), 3D orthogonal: plain (ORT-PW) and twill (ORT-TW), were subjected to 15 J impact using a 16 mm-diameter, 6.7 kg hemispherical impactor. Nondestructive techniques, including ultrasonic C-scanning, Digital Image Correlation (DIC) and X-ray computed tomography (CT) were used to map and quantify the size of the induced barely visible impact damage (BVID). The energy absorption of each architecture was correlated to the damage size: both in-plane and in-depth directions. The 3D architectures, regardless of their unit-cell size, demonstrated the highest impact resistance as opposed to 2D-PW and the NCF. X-ray CT segmentation showed the effect of the higher frequency of the z-binding yarns, in the ORT-PW case, in delamination and crack arresting even when compared to the other 3D architecture (ORT-TW). Among all the architectures, ORT-PW exhibited the highest damage resistance with the least damage size. This suggests that accurate design of the z-binding yarns’ path and more importantly its frequency in 3D woven architectures is essential for impact-resistant composite structures.

Enhancing the Ballistic Performances of 3D Warp Interlock Fabric Through Internal Structure as New Material for Seamless Female Soft Body Armor Development

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.

Understanding the ultra-high-temperature mechanical behaviors of advanced two-dimensional carbon-carbon composites

Advanced carbon-carbon composites (C/Cs) are tailored materials exhibiting properties designed to fit the end demands. However, as a kind of fiber reinforced materials, C/Cs have complex internal structures and various manufacturing defects which evolve with temperature. In addition, the micro-nano structures of the carbon fiber reinforcements and graphite matrix are susceptible to the thermal and graphitizing treatments. All these result in the complicated mechanical behaviors of C/Cs. Several experimental studies have been reported, but the mechanical parameters coupled together cannot be separated. Thus, the mechanical behaviors of C/Cs have yet been well understood. In the present work, theoretical models for the coefficient of thermal expansion, Young's modulus, and tensile strength of 2D C/Cs are established based on the mechanical mechanisms revealed in the ultra-high-temperature experiments. The mechanical behaviors of 2D plain-weave PAN based C/Cs at elevated temperatures are then studied. The factors contributing to the mechanical behaviors are separated and characterized quantitatively.

Fracture Strength Behaviors of Ultra-High-Temperature Materials

Abstract Ultra-high-temperature materials have been widely used as key components in high-end equipment. However, the existing studies are mainly conducted at room and moderate temperatures. Besides, they are mainly carried out by experiments. Theories on the temperature dependence of fracture strength are rarely reported. In this work, experimental methods for the ultra-high-temperature tensile properties of advanced materials and the elastic–plastic properties of coatings are developed, respectively, based on induction heating and radiation furnace heating technologies. A temperature-dependent fracture strength model for ceramics is proposed in the view of energy. The experimental methods and theoretical model are verified on the 2D plain-weave carbon fiber reinforced silicon carbide thermal structure composite, yttria-stabilized zirconia thermal barrier coating, and Si3N4 ceramics. The study shows that the mechanical properties of materials decrease significantly at ultra-high temperatures. The results are useful for the applications of ultra-high-temperature materials in thermal structure engineering.

Compression after multiple low velocity impacts of NCF, 2D and 3D woven composites

This paper investigates the effect of the fabric architecture and the z-binding yarns on the compression after multiple impacts behavior of composites. Four fiber architectures are investigated: non-crimp fabric (NCF), 2D plain weave (2D-PW), 3D orthogonal plain (ORT-PW) and twill (ORT-TW) weave. The specimens were subjected to single and multiple low-velocity impacts at different locations with the same energy level (15 J). Non-destructive techniques including ultrasonic C-scanning, X-ray CT and Digital Image Correlation (DIC) are employed to quantitatively analyze and capture the Barely Visible Impact Damage (BVID) induced in the specimens. Although the absorbed energy was approximately the same, damage was the least in 3D woven architectures. In the case of compression after impact, 3D woven composites demonstrated a progressive damage behavior with the highest residual strength (~92%) while 2D plain weave and NCF specimens showed suddenly catastrophic damage and the residual strength of ~65% and ~55% respectively.

The Failure Mechanism of Composite Stiffener Components Reinforced with 3D Woven Fabrics.

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.

Engineering of 3D warp interlock p-aramid fabric structure and its energy absorption capabilities against ballistic impact for body armour applications

3D warp interlock fabric became a promising structure to develop women body armour due to its good mouldability. However, its performance toward ballistic impact for different threats should be investigated before applying. This paper aims to investigate the ballistic performances of 3D interlock p-aramid (Twaron®) fabric panels’ against NIJ (National Institute of Justice) standard–0101.06 Level-IIIA. The intended fabric was manufactured on a semi-automatic loom in GEMTEX Laboratory. 2D plain weave fabric with similar fibre type was also tested for comparison. Various target panels from each structure were arranged and moulded at pre-defined points using an adapted bust-shape forming bench to resemble frontal female body contour. Based on the result, the energy absorption capabilities of 3D interlock and 2D fabric panels with a higher number of layers did not reveal a significant difference. However, the 2D fabric panel absorbed more energy than 3D warp interlock fabrics for a reduced and similar number of layers due to its rigid and stiffness property. Besides, both fabric types had shown less energy transmission to the backing material at the non-moulded target areas as compared to the moulded target area. While shaping the intended panel, 3D interlock fabric revealed better mouldability and less recovery behaviour with less wrinkle formations.

Wet oxidation behavior of SiC/(SiC‐ SiBCN)x composites prepared by CVI combined with PIOP process

AbstractSelf‐healing capability in wet oxygen atmospheres is the key issue for long term service of SiC/SiC composites in aero‐engines. Polymer derived SiBCN ceramic (PDC SiBCN) was introduced into SiC fiber reinforced SiC as a self‐healing component to obtain SiC/(SiC‐SiBCN)x composites by a newly developed method, namely chemical vapor infiltration combined with polymer infiltration online pyrolysis (CVI + PIOP) process. The weight loss behavior and three‐point bending performance of the samples under different temperatures (1200, 1300 and 1400°C) and different wet oxygen partial pressures were tested up to 100 hours to demonstrate the oxidation behavior of the samples in wet oxygen environments. According to these tests, the antioxidant capacities of samples prepared from different preforms were compared. It has been found that the 2D plain weave samples with higher density have the best resistance to wet oxygen corrosion while the 2D plain weave samples have the worst resistance to wet oxidation and the antioxidant capacities of 2D satin weave samples is between them.

Ring compression properties of SiCf/SiC composites prepared by chemical vapor infiltration

SiC fiber reinforced SiC matrix (SiCf/SiC) composites prepared by chemical vapor infiltration are one of promising materials for nuclear fuel cladding tube due to pronounced low radioactivity and excellent corrosion resistance. As a structure component, mechanical properties of the composites tubes are extremely important. In this study, three kinds of SiCf preform with 2D fiber wound structure, 2D plain weave structure and 2.5D shallow bend-joint structure were deposited with PyC interlayer of about 150–200 nm, and then densified with SiC matrix by chemical vapor infiltration at 1050 °C or 1100 °C. The influence of preform structure and deposition temperature of SiC matrix on microstructure and ring compression properties of SiCf/SiC composites tubes were evaluated, and the results showed that these factors have a significant influence on ring compression strength. The compressive strength of SiCf/SiC composites with 2D plain weave structure and 2.5D shallow bend-joint structure are 377.75 MPa and 482.96 MPa respectively, which are significantly higher than that of the composites with 2D fiber wound structure (92.84 MPa). SiCf/SiC composites deposited at 1100 °C looks like a more porous structure with SiC whiskers appeared when compared with the composites deposited at 1050 °C. Correspondingly, the ring compression strength of the composites deposited at 1100 °C (566.44 MPa) is higher than that of the composites deposited at 1050 °C (482.96 MPa), with a better fracture behavior. Finally, the fracture mechanism of SiCf/SiC composites with O-ring shape was discussed in detail.

Acoustic Emission from Microcrack Initiation in Polymer Matrix Composites in Short Beam Shear Test

Acoustic emission (AE) was applied for detection of microcrack initiation in carbon fiber reinforced polymer composites subjected to shear stresses. Experimental materials were prepared from polyester bonded unidirectional (1D) non-crimp fabric and 2D plain-weave carbon fiber fabrics, using the resin transfer moulding technology. Control of epoxy resin/carbon textile proportions enabled variation of fiber volume content from small (34/35% for 2D/1D), through medium (51%) to high (68%). Rectangular samples (45 times 4 times 2 mm) were cut from 1D plates along [0] and across [90] fibers. Similar size samples from 2D plates were cut along warp/weft axes as well as in two orthogonal bias directions. Selected side surfaces were polished for microscopic (SEM) observations. Short-beam-strength tests were performed in 3-point bending (l/h=4), with two AE sensors attached for damage monitoring, which allowed to interrupt loading sequence before final failure. The acoustic emission historic index was the most effective AE parameter in damage initiation control. Microcracks developing on polished composite side-surfaces were observed under the SEM and direct microscopic evidence confirmed fiber debonding to be the principal mechanism of crack initiation in these materials and testing conditions before any further damage.

Multi-scale Model of Residual Strength of 2D Plain Weave C/SiC Composites in Oxidation Atmosphere

Multi-scale models play an important role in capturing the nonlinear response of woven carbon fiber reinforced ceramic matrix composites. In plain weave carbon fiber/silicon carbon (C/SiC) composites, the carbon fibers and interphases will be oxidized at elevated temperature and the strength of the composite will be degraded when oxygen enters micro-cracks formed in the as-produced parts due to the mismatch in thermal properties between constituents. As a result of the oxidation on fiber surface, fiber shows a notch-like morphology. In this paper, the change rule of fiber notch depth is fitted by circular function. And a multi-scale model based upon the change rule of fiber notch depth is developed to simulate the residual strength and post-oxidation stress–strain curves of the composite. The multi-scale model is able to accurately predict the residual strength and post-oxidation stress–strain curves of the composite. Besides, the simulated residual strength and post-oxidation stress–strain curves of 2D plain weave C/SiC composites in oxidation atmosphere show good agreements with experimental results. Furthermore, the oxidation time and temperature of the composite are investigated to show their influences upon the residual strength and post-oxidation stress–strain curves of plain weave C/SiC composites.

Wave propagation in 3D viscoelastic auxetic and textile materials by homogenized continuum micropolar models

We analyze in this contribution the impact of wave damping on the dispersion features of 3D viscoelastic periodic structures, which are modeled as Kelvin–Voigt viscoelastic beam-lattices. The band diagram structure and damping ratio are computed for different repetitive structures, based on the micropolar viscoelastic response of the effective medium obtained by the homogenization of the initially discrete lattice architecture. The employed methodology is herewith exemplified for the cases of the 3D hexagon structure, which shows negative Poisson’s ratio for reentrant configurations, and the 2D plain weave textile structure. The dispersion relations and damping ratio are obtained by inserting an harmonic plane waves Ansatz into the dynamical equations of motion of the obtained effective viscoelastic anisotropic continuum. The 3D reentrant hexagon is an auxetic metamaterial showing excellent wave absorption capabilities, as reflected by the high incidence of partial band gaps. The textile plain weave structure shows a complete band gap for low frequencies. Comparing the frequency band structure of the effective continuum with that obtained by Floquet–Bloch analysis extended to a 3D context shows that the wave propagation characteristics can be directly obtained from the homogenized continuum at low frequencies.