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An extension of a constitutive law for 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is proposed with a focus on the calibration of a crystal plasticity law. TATB, a highly anisotropic energetic molecular crystal used in explosive formulations, can be subjected to high-pressure and high-temperature conditions, either under high strain-rate deformation or shock loading. The existing thermodynamically consistent model, fully informed by molecular dynamics (MD) simulations, includes nonlinear elasticity as well as a phase-field by reaction pathway formalism under large strain for the modeling of TATB behavior upon pressure as well as its well-known twinning–buckling deformation mechanism. However, it has been observed that TATB single crystal can accommodate large deformations through dislocation-mediated plasticity, a feature not included in the mesoscale model. In the present work, we take advantage of the microscopic flow surface, previously computed through MD calculations, to calibrate a crystal plasticity law, extending the capability of the continuum model currently limited to low velocity impacts and moderate strain rate. Indeed, the microscopic flow surface, defined as a 3D stress-at-first-defect-nucleation contains all information about TATB single crystal mechanical response under directional shear loading, including twinning, buckling, and plastic events. The calibration process uses differential evolution optimization to calibrate TATB basal and transverse slip systems critical stresses to reproduce the microscopic flow surface. Finally, the response of a TATB single crystal to directional loading is investigated in order to evaluate the new model. [ABSTRACT FROM AUTHOR]

In this paper, the transverse low-velocity impact behavior of uniaxial and biaxial braided composite tubes is investigated to improve the impact resistance of tubular composite structures and to reveal their energy absorption mechanism. Based on the nonlinear progressive damage model, the finite element method is used for experimental verification and numerical analysis. The composite tubes with different stacking sequences and stacking angles were simulated, and their impact responses were evaluated by the peak load Fmax, the maximum indentation depth αmax and the energy absorption EA. The results show that the numerical simulation results are in good agreement with the experimental data, and can accurately capture the failure behavior in the actual scene. The damage mode of the braided composite circular tube under low-velocity impact load is mainly manifested as matrix cracking and interlayer separation, and the expansion direction of the damaged area is basically consistent with the fiber orientation. The impact resistance depends more on the stacking sequence, while the stacking angle is the main factor affecting the energy absorption. Under reasonable design, the uniaxial/biaxial hybrid braided tube can obtain the best low-velocity impact characteristics. [ABSTRACT FROM AUTHOR]

Woodwork is involved in a variety of interactions with humans through physical contact, which may reveal valuable information if the tactile data can be unnoticeably extracted. In this work, an intelligent iontronic wood (iWood) device, along with its seamlessly integrated architecture into the woodwork, enabled by the iontronic sensing principle, is implemented. Notably, the tactile sensing structure is generated at the iontronic interface between ionic and conductive woods. In particular, the ionic wood is established by infusing an ionic liquid into the wood, followed by immobilizing it via chemical bonding, presenting both prominent ionic conductivity and excellent stability under pressure. By formatting the woods into identical strips, the high‐density tactile sensing array can be simply formed by a braiding process for a scalable interwoven structure. As a result, the iWood device has offered a high sensitivity over a broad detection of 0.5 MPa and an array of 40 × 90 units covering an area up to 3600 cm2. The iWood device is showcased as an interactive human interface, demonstrating its potential as a smart desktop capable of gesture and object recognition, a health‐tracking chair for real‐time ballistocardiograph monitoring, and an embedded intelligent floor for weight management and gait analysis. [ABSTRACT FROM AUTHOR]

In this paper, we will investigate the structural, electronic, mechanical, magnetic and optical properties of Heusler Mn2NiAl (MNA) compound using the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) of the full potential linearized augmented plane-wave method for exchange and use correlations, modified Becke–Johnson and GGA+U Hubbard parameter. The calculated band structure (BS) and density of states (DOS) of MNA showed a metallic (GGA), nearly half-metallic (mBJ) and half metallic (GGA+U) behavior. Moreover, the magnetic computed magnetic moments by GGA+U are higher compared to GGA and mBJ results. Bulk modulus, shear modulus, Voigt and Reuss polycrystalline elastic modulus, Debye temperature, sound velocities, the melting temperatures, B / G ratio, Young's modulus and Poisson's ratio were obtained. The elastic anisotropy of MNA alloy was analyzed using 2D and 3D figures of directional dependence of Poisson's ratio, shear modulus, linear compressibility and Young's modulus. Studies have shown that the Heusler material MNA has magnetic and anisotropic properties and is mechanically stable. [ABSTRACT FROM AUTHOR]

Braided composite structures, characterized by their inherent brittleness, necessitate precise damage prediction and prevention to ensure structural integrity/reliability. This study introduces an innovative method for enhancing damage resistance in tubular triaxial hybrid braided composites. These composites employ Epoxy resin as the matrix, with polyester serving as the bias yarn, and glass and basalt as the axial yarns, woven at varying braiding angles. Tensile tests reveal a compelling trend: a reduction in the braiding angle correlates with an increase in the failure load, indicative of quasi‐ductile behavior. A model is also derived for predicting tensile elastic modulus, which demonstrates a strong correlation with experimental results. Furthermore, finite element simulations are utilized to analyze damage within the triaxial hybrid braided composite specimens, providing empirical confirmation of progressive damage occurrence. This research offers a promising avenue for designing/manufacturing advanced composite materials with superior damage‐resistance holding immense potential across a spectrum of engineering applications. Highlights: The tubular triaxial hybrid braided composites were produced by Epoxy resin as the matrix, with polyester as the bias yarn, and glass and basalt as the axial yarns at different braiding angles.An innovative method was introduced for enhancing damage resistance in tubular triaxial hybrid braided composites.The effect of operating parameters (braiding angle, type of bias yarns, production method) was investigated.Was tried to predict tensile modulus values in tubular triaxial hybrid braided composites by finite element simulation and developed equations.Finite element simulation exhibited excellent performance in the prediction of tensile behavior of structures manufactured by the innovative method. [ABSTRACT FROM AUTHOR]

Native tissues feature unique hierarchical designs, in which fiber units are arranged from the bottom up in anisotropic patterns. The processing of biomaterials into fibers, followed by their textile‐like assembly into complex patterns, is therefore a promising avenue to engineer native‐like tissue replacements. Here it is shown for the first time the fabrication of meter‐long hydrogel fibers prepared from engineered elastin using a microinjection system and exploiting the catalyst‐free click chemistry. Given their similarity to native elastin, the fabricated elastin‐like fibers achieved excellent stretching (500%) and recoiling performance. Moreover, the fabrication scheme is compatible with the implementation of a salt‐leaching gas‐foaming approach, resulting in highly porous elastin‐like fibers (the first of their kind). From the translation perspective, the fibers can be autoclaved, which allows for sterilization and long‐term storage. Human umbilical vein endothelial cells cultured on autoclaved fibers produced a confluent endothelial layer lining the fiber surface, in which the cells became aligned in response to physiological fiber stretching. It is also shown that these functional fibers can be assembled by weaving, braiding and knitting, with various spatial patterns. Overall, the elastin‐like fibers can be used as building blocks for the reconstruction of functional tissues using the principles of textile technology. [ABSTRACT FROM AUTHOR]

In this paper, 3D braided composites are considered for high-performance piezoelectric energy harvester designing, and a 3D braided composite piezoelectric energy harvester (3D BCPEH) is proposed. The advantage of 3D BCPEH is that the natural frequency of the device can be adjusted by adjusting the stiffness of the spring, making the natural frequency of the device close to the vibration frequency of the environment, thereby achieving the best harvesting effect of the energy harvester. During the vibration process, spring support can cushion the impact and stress on the piezoelectric energy harvester, thereby protecting the device from damage and helping to improve the stability and performance of the system. Finite element analysis is used to obtain the elastic modulus, shear modulus, and Poisson's ratio of 3D braided composites with varying braiding angles. Based on Hamilton's variational principle, the vibration control equation of the spring supported 3D BCPEH is derived. The effects of spring rate, braiding angle, external excitation acceleration, external load resistance, and structure size on the output response of 3D BCPEH are simulated and analyzed. The validity of the proposed 3D BCPEH with spring support is confirmed by the simulation results. [ABSTRACT FROM AUTHOR]

Resin matrix composites (RCs) have better thermal and chemical stability, so they are widely used in engineering fields. In this study, the aging process and mechanism of two different types of resin-based three-dimensional four-way braided composites (H15 and S15) under different hygrothermal aging conditions were studied. The effect of aging behavior on the mechanical properties of RCs was also studied. Three different aging conditions were studied: Case I, 40 °C Soak; Case II, 70 °C Soak; and Case III, 70 °C-85% relative humidity (RH). It was found that the hygroscopic behavior of RCs in the process of moisture-heat aging conforms to Fick's second law. Higher temperatures and humidity lead to higher water absorption. The equilibrium hygroscopic content of H15 was 1.46% (Case II), and that of S15 was 2.51% (Case II). FT-IR revealed the different hygroscopic mechanisms of H15 and S15 in terms of aging behavior. On the whole, the infiltration behavior of water molecules is mainly exhibited in the process of wet and thermal aging. At the same time, the effect of the aging process on resin matrices was observed using SEM. It was found that the aging process led to the formation of microchannels on the substrate surface of S15, and the formation of these channels was the main reason for the better moisture absorption and lower mechanical strength of S15. At the same time, this study further found that temperature and oxygen content are the core influences on post-aging strength. The LVI experiment also showed that the structural changes and deterioration effects occurring after aging reduced the strength of the studied material. [ABSTRACT FROM AUTHOR]

Highlights: A composite thermal interface material with three-dimensional hybrid carbon network-reinforced polydimethylsiloxane was proposed. The cooperative regulation of thermal conductivity and mechanical properties was achieved by controlling the assembly process of micro-nano scale unit carbon materials. The orthotropic continuous carbon structure endowed the composites with in-plane and out-of-plane thermal conductivities of up to 113.61 and 24.37 W m−1 K−1, respectively. The excellent compressibility and adhesion properties cooperatively improved the effective thermal conductivity by more than an order of magnitude. Vertically oriented carbon structures constructed from low-dimensional carbon materials are ideal frameworks for high-performance thermal interface materials (TIMs). However, improving the interfacial heat-transfer efficiency of vertically oriented carbon structures is a challenging task. Herein, an orthotropic three-dimensional (3D) hybrid carbon network (VSCG) is fabricated by depositing vertically aligned carbon nanotubes (VACNTs) on the surface of a horizontally oriented graphene film (HOGF). The interfacial interaction between the VACNTs and HOGF is then optimized through an annealing strategy. After regulating the orientation structure of the VACNTs and filling the VSCG with polydimethylsiloxane (PDMS), VSCG/PDMS composites with excellent 3D thermal conductive properties are obtained. The highest in-plane and through-plane thermal conductivities of the composites are 113.61 and 24.37 W m−1 K−1, respectively. The high contact area of HOGF and good compressibility of VACNTs imbue the VSCG/PDMS composite with low thermal resistance. In addition, the interfacial heat-transfer efficiency of VSCG/PDMS composite in the TIM performance was improved by 71.3% compared to that of a state-of-the-art thermal pad. This new structural design can potentially realize high-performance TIMs that meet the need for high thermal conductivity and low contact thermal resistance in interfacial heat-transfer processes. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of varying the part geometric complexity and 3D printing process setup on the resulting structural load bearing capacity of fiber composites. Three levels of geometric complexity are developed through 2.5D topology optimization, 3D topology optimization, and 3D topology optimization with directional material removal. The 3D topology optimization is performed with the SIMP method and accelerated by high-performance computing. The directional material removal is realized by incorporating the advection-diffusion partial differential equation-based filter to prevent interior void or undercut in certain directions. A set of 3D printing and mechanical performance tests are performed. It is interestingly found that, the printing direction affects significantly on the result performance and if subject to the uni direction, the load-bearing capacity increases from the 2.5D samples to the 3D samples with the increased complexity, but the load-bearing capacity further increases for the 3D simplified samples due to directional material removal. Hence, it is concluded that a restricted structural complexity is suitable for topology optimization of 3D-printed fiber composites, since large area cross-sections give more degrees of design freedom to the fiber path layout and also makes the inter-layer bond of the filaments firmer. [ABSTRACT FROM AUTHOR]

To comply with the trend in the development of engineering materials towards lightweight, high strength, eco-friendly, sustainable, and multi-functional, a three-dimensional braided integrated composite honeycomb is designed. The effects of geometrical parameters particularly joint wall lengths on the in-plane mechanical behavior of the honeycombs were investigated. The results show that the in-plane mechanical properties are related to the number of cell walls, and the angle between the cell wall and the loading direction. Increasing the number of cell rows to double and triple at similar areal density lead to an improvement of the maximum load up to 2.5, and 3.8 times, respectively. Similarly, the total absorbed strain energy increased up to 2.6 and 5.9 times, respectively. The displacement at the maximum load is increased by 1.6 and 2.7 times as a result of increasing the cell row number. The total absorbed strain energy increased to 1.7 and 1.3 times, respectively. The failure angle of the 3D braided composite honeycomb is about 4°–7°. This investigation presents the geometrical factors of a 3D braided composite honeycomb can be further designed and optimized, but it also provides a reference for the development and design of a new composite honeycomb. [ABSTRACT FROM AUTHOR]

This study aimed to develop a method for rapid and precise measurement of the elastic modulus at high temperatures. High‐temperature in‐situ microscopy was used in conjunction with a testing apparatus to measure the deformation of a specimen in three‐point bending test. The bending deflection was determined in situ by measuring the relative change between the test point on the specimen and a fixed reference point. The deflection was correlated with the elastic modulus to obtain the dependence of the elastic modulus on temperature. The ratio between high‐ and room‐temperature deflection of the bending beam was measured using the relative method and image analysis, with an identical scene and focal length for each photograph and a resolution of less than 1 µm. The deflection ratio was then converted into the ratio between high‐ and room‐temperature elastic modulus, enabling the high‐temperature modulus to be quickly derived. The experiments were performed on a sample made of silicon carbide fiber braided layered composite. The results showed that the elastic modulus changed little within 1100°C, remaining between 80 and 84 GPa. Contrarily, constant‐load tests indicated that the creep of this material was noticeable, making it difficult to obtain reliable elastic modulus. [ABSTRACT FROM AUTHOR]

For efficient and stable large-scale water electrolysis, practical industrial electrodes should meet the following characteristics: high activity, structural stability, and fast bubble removal. Here we report a structured electrode (NiS–Co–NiP) prepared via 3D printing of nickel-based substrate and subsequent electrodeposition for the hydrogen evolution reaction (HER). With unique 3D nanosheets, the NiS–Co–NiP electrode exhibits large electrochemical surface area (ECSA), strong hydrophilicity, high mechanical strength and electrical conductivity, delivering outstanding HER activity. It requires low overpotentials of 134 mV and 169 mV to achieve the current densities of 100 mA cm−2 and 300 mA cm−2, respectively. Moreover, rational design of the NiS–Co–NiP electrode in pyramidal geometry facilitates directional bubble transport and electrolyte flow, resulting in superior stability of 350 h at a current density of 150 mA cm−2. This work demonstrates a new approach for manufacturing binder-free structured electrode of excellent HER performance at high current densities. [Display omitted] • Preparing a structured NiS–Co–NiP electrode by 3D printing and electrodeposition. • The superwetting NiS–Co–NiP electrode shows outstanding HER activity. • 3D pyramidal geometry enables directional bubble traffic and electrolyte flow. • 3D pyramidal geometry favors stable performance at large current hydrogen evolution. [ABSTRACT FROM AUTHOR]

Reducing the wear of carbon fibers on braiding carriers is the key to manufacturing high‐performance carbon fiber composite prefabricated parts. In this study, a new analytical model is developed to describe the local friction behavior of yarns on braiding carriers. The degree of yarn wear is characterized by calculating the gray value of carbon fiber hairiness and observing the micro‐surface morphology of carbon fibers. The wear characteristics of carbon fiber yarns under the multi‐factor coupling influences of yarn tension, unwinding speed, and guiding element characteristics were considered. The results show that increases in unwinding angle and unwinding speed both increase the wear of carbon fiber yarns. Eliminating the effect of unwinding angle can reduce the yarn hairiness by more than 60%, alleviate the yarn tension fluctuation by more than 70%, and improve the yarn tension stability by more than 75%. Meanwhile, the relationship between the wrapping angle between the yarn and the yarn bobbin, the unwinding angle, and the yarn tension was established according to the Capstan Equation. A method is proposed to improve the characteristics and spatial position of the guiding elements to obtain more intact yarn and low‐damage yarn surfaces. Highlights: A new analytical model for local friction of carbon fibers is developed.The friction‐wear‐fracture mechanism of carbon fiber yarns is constructed.Characterize the degree of yarn wear from a macro and micro perspective.Wear characteristics of carbon fiber yarns under multi‐factor coupling. [ABSTRACT FROM AUTHOR]

3D braided composites consolidated by heat-resistant resin are expected to become essential structural material of new generation aerospace vehicles. In this work, the thermo-mechanical behavior of 3D braided composites subjected to general off-axis tensile loadings at room and elevated temperatures is evaluated based on the meso-scale finite element (FE) model. A user-material subroutine UMAT is adopted to implement the thermal stress analysis, temperature-dependent failure initiation criteria and material properties degradation scheme of both fiber yarns and matrix. The meso-scale damage evolutions under thermal-mechanical coupling loads are simulated based on ABAQUS/Standard and the corresponding detailed failure mechanisms are revealed. The off-axial elastic moduli and strengths of 3D braided composites under elevated temperatures are also predicted. The numerical results indicate that high temperature affects the material properties mainly by weakening the matrix properties while off-axis loading affects the damage mechanisms by changing the load distribution of fiber yarn in each direction. The present work provides routine support for the numerical study of structural properties and damage behavior of other textile composites in service temperature environment. [ABSTRACT FROM AUTHOR]

This paper studies the mechanical properties of the 2-D tri-axial braided composite. A volume element is established, so that the classical laminate plate theory and the series-parallel model can be adopted to study a bi-directional stress--strain response. Failure criteria are given and the failure strength is determined. The finite element simulation is used to verify the reliability of the present theoretical model. [ABSTRACT FROM AUTHOR]

A three-dimensional helix geometry unit cell is established to simulate the complex spatial configuration of 3D braided composites. Initially, different types of yarn factors, such as yarn path, cross-sectional shape, properties, and braid direction, are explained. Then, the multiphase finite element method is used to develop a new theoretical calculation procedure based on the unit cell for predicting the impacts of environmental temperature on the thermophysical properties of 3D four-direction carbon/epoxy braided composites. The changing rule and distribution characteristics of the thermophysical properties for 3D four-direction carbon/epoxy braided composites are obtained at temperatures ranging from room temperature to 200 °C. The influences of environmental temperature on the coefficients of thermal expansion (CTE) and the coefficients of thermal conduction (CTC) are evaluated, by which some important conclusions are drawn. A comparison is conducted between theoretical and experimental results, revealing that variations in temperature exert a notable influence on the thermophysical characteristics of 3D four-directional carbon/epoxy braided composites. The theoretical calculation procedure is an effective tool for the mechanical property analysis of composite materials with complex geometries. [ABSTRACT FROM AUTHOR]

Cellular approaches facilitate the flexible design of materials with desirable properties that may be manufactured from single polymers, metals, and, recently, fiber-reinforced composites. This paper describes cellular materials with metal and carbon fiber-reinforced plastic (CFRP) struts. Composite lattice tubular structures were automatically braided, and the effects of axial CFRP yarns on the compressive behaviors of braided lattices were studied. Metal wire-reinforced plastic and metal rods served as axial yarns when preparing hybrid triaxially braided metal-CFRP lattices. The effects of the axial yarns in polyurethane (PU) foam-filled samples were also assessed. Ten braided structures were manufactured, and their compressive behavior and energy absorption were evaluated by axial compression tests. Finite element (FE) simulations were used to investigate deformation, buckling, and damage. Addition of axial CFRP yarns improved the compressive properties; the specific absorbed energy (SAE) increased by 16%. Hybridization further enhanced the SAE by 62%. [ABSTRACT FROM AUTHOR]

Wearable heaters are essential for people living in cold regions, but creating heaters that are low-cost, lightweight, and high air permeability poses challenges. In this study, we developed a wearable heater using carbon nanotube/water polyurethane (CNT/WPU) nanocomposite fibers that achieve high extension rate and conductivity. We produced low-cost and mass-produced fibers using the wet spinning. With heat treatment, we increased the elongation rate of the fibers to 1893.8% and decreased the resistivity to 0.07 Ω*m. then wove the fibers into a heating fabric using warp knitting, that resistance is 493 Ω. Achieved a uniform temperature of 58 °C at voltage of 36 V, with a thermal stability fluctuation of −5.0 °C to +6.3 °C when bent from 0° to 360°. Our results show that wearable heaters have excellent flexibility and stretchability, due to nanocomposite fibers and special braided structure, which offer a novel idea for wearable heaters. [ABSTRACT FROM AUTHOR]

Brazing a SiO2f/SiO2 composite with metals is often faced with two problems: poor wettability with the brazing alloy and high residual stress in the joint. To overcome these problems, we report a combined method of selective etching and depositing reduced graphene oxide (rGO) on the surface of a SiO2f/SiO2 composite (3D-rGO-SiO2f/SiO2) to assist brazing with TC4. After the combined treatment, a "3D-rGO" buffer layer formed on the surface layer of the SiO2f/SiO2, and the contact angle was reduced from 130° to 38°, which meant the wettability of active brazing alloy on the surface of SiO2f/SiO2 was obviously improved. In addition, the "3D-rGO" buffer layer contributed to fully integrating the brazing alloy and SiO2f/SiO2; then, the infiltration of the brazing alloy into the surface layer of the SiO2f/SiO2 was enhanced and formed the reduced graphene oxide with a pinning structure in the three dimensional ("3D-pinning-rGO") structure. Moreover, the joining area of the brazing alloy and SiO2f/SiO2 was expanded and the mismatch degree between the SiO2f/SiO2 and TC4 was reduced, which was achieved by the "3D-pinning-rGO" structure. Furthermore, the concentration of the residual stress in the SiO2f/SiO2-TC4 joints transferred from the SiO2f/SiO2 to the braided quartz fibers, and the residual stress reduced from 142 MPa to 85 MPa. Furthermore, the 3D-pinning-rGO layer facilitated the transfer of heat between the substrates during the brazing process. Finally, the shear strength of the SiO2f/SiO2-TC4 joints increased from 12.5 MPa to 43.7 MPa by the selective etching and depositing rGO method. [ABSTRACT FROM AUTHOR]

The elasticity matrix and the coefficients of thermal expansion (CTEs) of 8-harness satin-woven (8HS) carbon-fiber-reinforced carbon matrix (C/C) composites at high temperatures were obtained by the asymptotic homogenization method (AHM) and finite element method (FEM). By analyzing the microstructure of the 8HS C/C composites, a representative volume element (RVE) model considering a braided structure was established. The effects of the temperature and component volume fraction on the elasticity matrix and CTEs of the composites were investigated. The sensitivity of model parameters, including the size of RVE model and mesh sensitivity, were studied. The optimal calculation model was employed. In addition, the effects of the 4HS methods and 8HS methods on the elastic constants of the composites were compared. The temperature and variation in the carbon fiber volume fraction were found to have a significant impact on the elasticity matrix and CTEs of composite materials. At the same volume fraction of carbon fibers, some elastic coefficients of the 4HS composite material were slightly lower than those of 8HS composite material. This research affords a computational strategy for the accurate prediction of the themo-mechanical properties of satin-woven C/C composites. [ABSTRACT FROM AUTHOR]

In order to realize the lightweight design of the transmission system, the braided composite material is applied to the two-stage gear transmission system. According to the structural characteristics of the two-stage gear reducer box, the whole box is designed to be assembled with the braided base and the box wall. Woven composite materials are applied to the web parts of mixed metal composite gears to realize the design goal of lightweight gears. Then, under the assumption of ignoring the influence of friction, bearings and other factors on the system, the dynamic model of the two-stage gear transmission system considering the box is established. By normalizing and dimensionless processing of the equations, the dimensionless differential equations of motion are obtained. The fourth-order Runge–Kutta method is used to analyze the relationship between the connection parameters and the dynamic characteristics of the system under the two working conditions of rigid and flexible connection between the composite base and the box wall.Through the analytical analysis of vibration displacement of two-stage gear reducer and box, the theoretical basis is found for the numerical analysis results. Finally, the dynamic characteristics of the transmission system are studied by vibration resonance analysis through high and low frequency interference. It is found that in a certain frequency range, with the decrease of the mass and moment of inertia of the transmission parts corresponding to the mixed metal composite gear, the amplitude-frequency characteristic Q of the lightweight gear and gearbox transmission system is slightly lower than that of the common gear and gearbox system, and the stability of the system is increased, and the dynamic characteristics of the system are improved. [ABSTRACT FROM AUTHOR]

In 3D braided composites, some fibers are oriented in thickness directions, increasing strength and reducing de-lamination ability. The equivalent elastic properties of the 3D braided plate are computed using a volume averaging approach. Here, the low-velocity impact of the 3D braided plate is investigated at various locations based on the 3D shear deformations theory incorporated with twelve-degree freedom per node using an eight nodded isoparametric finite element method. In this theory, transverse displacement is the function of the thickness coordinates, which is the unique advantage of this theory. The various parametric studies are performed by varying geometrical and material parameters. [ABSTRACT FROM AUTHOR]

Introduction: The prevalence of horizontal neck lines as a cosmetic concern is widely acknowledged, yet the available treatment options are limited, and no studies have investigated the use of polydioxanone‐barbed threads. These threads, characterized by a finely braided structure, function as a scaffold to attract regenerative factors and facilitate the migration and proliferation of cells. This study aims to evaluate the outcomes of concurrent application of braided polydioxanone‐barbed threads for addressing horizontal neck wrinkles. Methodology: A retrospective case series involving four female participants (aged 41, 43, 45, and 46) treated with polydioxanone‐barbed threads for horizontal neck wrinkles between January 2023 and July 2023 was conducted. Adult patients were assessed at an 8‐week follow‐up, revealing a significant reduction in wrinkle intensity based on the Horizontal Neck Wrinkle Severity Scale. Results: The analysis of horizontal neck lines demonstrated a notable decrease in wrinkle intensity according to the Horizontal Neck Wrinkle Severity Scale at the 8‐week mark, and this improvement maintained statistical significance. Both patient Global Aesthetic Improvement Scale (GAIS) scores (90%–100%) and physician GAIS scores (100%) were rated as excellent. Conclusion: The subdermal application of polydioxanone‐barbed threads for horizontal neck lines proves to be a secure and efficacious approach for treating horizontal neck wrinkles, with no observed Tyndall effect. This technique shows promise for rejuvenating the skin in the horizontal neckline region. [ABSTRACT FROM AUTHOR]

In this article, the piezoelectric patches are embedded into three‐dimensional (3‐D) braided composite material (BCM), and a 3‐D embedded braided composite piezoelectric vibration energy harvester (BCPEH) is designed. The 3‐D embedded BCPEH can be applied in more complex working environments to protecting the piezoelectric patches, and has a longer lifespan. The material parameters of the 3‐D BCM are obtained by analyzing the representative volume units (RVU). Using Hamilton's variational principle, the vibration control equation, and the output voltage and power expression are derived. The influence of excitation frequency, load resistance, and external excitation on the output voltage and power are simulated under different braided angles and embedded depths. [ABSTRACT FROM AUTHOR]

We study the simplest example of mirror symmetry for 3d = 4 SUSY gauge theories: the A-twist of a free hypermultiplet and the B-twist of SQED. We particularly focus on the category of line operators in each theory. Using the work of Costello–Gaiotto, we define these categories as appropriate categories of modules for the boundary vertex operator algebras present in each theory. For the A-twist of a free hyper, this will be a certain category of modules for the β γ VOA, properly containing the category previously studied by Allen-Wood. Applying the work of Creutzig–Kanade–McRae and Creutzig–McRae–Yang, we show that the category of line operators on the A side possesses the structure of a braided tensor category, extending the result of Allen-Wood. In addition, we prove that there is a braided tensor equivalence between the categories of line operators on the A side and B side, completing a nontrivial check of the 3d mirror symmetry conjecture. We derive explicit fusion rules as a consequence of this equivalence and obtain interesting relations with associated quantum group representations. [ABSTRACT FROM AUTHOR]

Different failure modes occur in textile‐reinforced composite under applied loads. Fracture mechanism of braided composites are closely related to the geometry of braids. In the present study, fracture mechanism of glass/epoxy braided composite cylinders is investigated under tensile loads. For this purpose, glass/epoxy braided composites were fabricated using braids with braiding angles of 30°, 45°, and 57° to find the role of fiber path on the fracture mechanism. To determine the fiber path, helixes on the cylinders with aforementioned angles was considered and analyzed. New fixtures (jaws) were designed and manufactured for tensile testing of cylindrical composites. Tensile tests were carried out on the prepared samples to evaluate the failure modes of composites. The SEM micrographs of samples are provided after tensile test. Various failure modes were observed regarding the angle of the braid. Fiber breakage, matrix fracture, and debonding are the dominant modes that occur in braided composites proportional to the angle of braids. Fiber breakage is the dominant mode in the 30° angle braid reinforced composite, while the dominant failure mode in the 57° angle braid reinforced composite is matrix fracture. In composites with a braid angle of 45°, a combination of fracture modes occurred. In addition, energy absorption as well as specific energy absorption (SEA) of braided composite cylinders were also investigated and obtained from load–displacement curves. The results showed that the reinforced composite with a braid angle of 30° absorbs the lowest amount of energy (21.5 J) and also the lowest amount of specific energy (5375 J/kg). The maximum absorbed energy (67.7 J) and the maximum SEA (9675 J/kg) were observed in the reinforced composite with a braid angle of 45°. Highlights: Fiber breakage is the dominant mode at the 30° angle braid reinforced composite.The dominant failure mode at the 57° angle braid reinforced composite is matrix fracture.In composites with the braid angle of 45°, a combination of fracture modes occurred.The composite reinforced with a braid angle of 30° absorbs the lowest amount of energy (21.5 J) and also the lowest amount of specific energy (5375 J/kg).The maximum absorbed energy (67.7 J) and the maximum SEA (9675 J/kg) were observed in the reinforced composite with a braid angle of 45°. [ABSTRACT FROM AUTHOR]

The working condition of the rail transit components such as bogies is complicated, so the high comprehensive performance of composite parts is desperately required. However, existing pure three‐dimensional braided or laminated composites have been unable to satisfy the cooperative demand of in‐plane and interlaminar properties. In this paper, a novel design of three‐dimensional braided/unidirectional (3D/UD) hybrid composite is proposed to balance the in‐plane (tensile, compression, bending), interlaminar (interlaminar shear, low‐speed impact) properties of the composite. The effects of different 3D/UD mixing ratio and layup sequence on the mechanical properties and damage mechanism of hybrid composites were studied by the parametric analysis of the experimental test results, and the comprehensive mechanical properties of the hybrid structure were optimized by COPRAS evaluation method. The results show that the larger the proportion of unidirectional layer, the better the mechanical property in‐plane, but the worse interlayer property. In addition, the change of layup sequence induces a complex nonlinear relationship between 3D/UD mixing ratio and mechanical properties. Combined with microscopic failure characterization results, it is found that the sandwich structure and the addition of uniformly distributed interfacial layer can improve the mechanical properties of the hybrid composite. The optimization results show that the sandwich structure hybrid composite UD6/3D/UD6 with the best balance between in‐plane and interlaminar properties was selected by COPRAS. Compared with pure 3D composites, the comprehensive mechanical properties of UD6/3D/UD6 are increased by 53.9%, which provides a reference for the structural design of hybrid composites in the future. Highlights: A novel design of 3D/UD hybrid composite is proposed to balance the in‐plane and interlaminar properties.The influence regularity of 3D/UD mixing ratio and layup sequence on properties of hybrid composites were obtained.The mixing failure mechanism of interlayer and in‐plane was revealed.The optimal structure UD6/3D/UD6 under complex working conditions was obtained by COPRAS. [ABSTRACT FROM AUTHOR]

Composite pressure vessels (CPVs) are lightweight and high-strength containers that can be used for the storage of compressed gases, including hydrogen. While hydrogen is a promising alternative energy source, storage of hydrogen comes with its significant challenges which requires a need for the efficient production of CPVs. Most commonly, CPVs are manufactured using filament winding technology. Due to the rise in the need for pressure vessels, there is a need for alternative high-throughput manufacturing techniques. Braided, in comparison to filament winding, has a high throughput and is less research manufacturing technology for CPVs. In this study, the applicability of braiding for the manufacturing of CPV is researched. Two types of 2D braids, namely the conventional and unidirectional, braiding were studied for their application in such structures, 24K and UD tanks, respectively. Dry carbon fiber (T700S – 24K) and HDPE liner were used to manufacture two different types of composite pressure vessels (CPVs), by robot-assisted radial braiding technique. After the preform of the braiding process was finished, CPVs were cured with a vacuum infusion process (VIP) by using a mold system. Produced braided CPVs were subjected to a hydrostatic burst test in order to determine their ultimate burst pressure point. Finite element analysis (FEA) was used to optimize and correlate experimental burst pressure test results. Ansys ACP was utilized to design composite structures by dividing both tanks' domes into sub-sections. Results suggest that the experimental burst pressure test of 24K and UD tanks were identified as 200 bar and 150 bar, respectively. UD vessel ruptured close to the dome, whereas the 24K fracture point was located in the center of the dome. UD braided CPV was shown to have a smaller apparent burst deformation (rupture) scale than 24K CPV. In comparison to 24K, the UD braided CPV is 5.7% lighter and requires 20.9% less carbon fiber in production. FEA results were consistent with experimental results in terms of the burst pressure point. For both 24K and UD, the fiber failure starts at the point where the cylinder section and boss system are connected under pressure, and fiber failures continue to progress steadily as the pressure increases. [Display omitted] • The manufacturing process of braided preforms for the composite pressure vessels (CPVs) is successfully achieved. • Two kinds of braided CPVs were produced to evaluate the ultimate burst pressure. • Experimental burst points of 24K and UD tanks were identified as 200 bar and 150 bar, respectively. • Finite element analysis was in agreement with experimental results in terms of burst pressures. • 24K fracture location was situated near the center of the dome, whereas the UD ruptured close to the dome. [ABSTRACT FROM AUTHOR]

Let n, m ∈ ℕ, n ≥ 3 and n ≥ m ≥ 2. In this paper, we study some properties of the unrestricted virtual singular braid of braid monoid UVSBmn and group UVSGmn. These properties emerged by studying the analogous properties of the unrestricted virtual singular pseudosymmetric braid of braid monoid and group. These mathematical objects are submonoids and subgroups of the virtual singular braid group VSGn. For many of these quotients, we have obtained reduced presentations. [ABSTRACT FROM AUTHOR]

The use of water detection (WD) indices to infer daily discharge (Qd) has a great potential to enrich needed hydrological data for understanding fluvial processes driving the morphological changes of braided rivers. However, no consensus has been reached on which one stands out for use in mid-sized braided rivers. In this study, we compared the physical characteristics of three most commonly used WD indices, the Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI), and Normalized Difference Moisture Index (NDMI), for two mid-sized braided reach segments in the Qinghai-Tibet Plateau, China, that have different morphological structures. Relying on the Google Earth Engine web interface, we calculated the total mean water width (WWt) based on the detected surface-water areas (As) and braiding index (BI), as well as the mean values (m) of these indices over about four decades at the braided corridor scale (cs) (mNDWIcs, mMNDWIcs, and mNDMIcs). We then examined different responses of these indices to water and non-water features and their best threshold values for characterizing channel structures. Our analyses demonstrated that (1) NDWI and MNDWI perform well for detecting braided channel structures with the threshold of zero; (2) WWt is generally better correlated to Qd in a linear style than WD indices do, particularly when calculated from MNDWI; and (3) among WD indices calculated at the braided corridor scale, mMNDWIcs shows a better relationship with Qd than mNDMIcs does. Finally, we provided mechanisms that may explain these differences in terms of photometric discrepancies in calculating WWt and WD indices and the impact of image resolution on their calculations. [ABSTRACT FROM AUTHOR]

Aiming at the issues of poor toughness, low folding endurance, and susceptibility to damage of silicon carbide (SiC) fiber tows during repeated folding process, two-dimensional (2D) SiC fiber braided fabrics with varying braiding angles were prepared in this study. The folding endurance and damage mechanisms of SiC fiber fabrics under different folding conditions were investigated through repeated folding tests, tensile tests, and optical microscope measurements. The results revealed that when the folding angle was (+180°, −180°), the SiC fiber braided fabric with a lower braiding angle (α = 37.8°) exhibited a folding endurance number of 1984 times, while the medium angle fabric (α = 41.2°) had a value of 761 times, and the high angle fabric (α = 43.1°) achieved 1733 times. During the folding process, both interlaced abrasion between fiber tows and external folding loads affected the mechanical properties of SiC fiber tows and their fabrics leading to material damage. Initially, the folding load played a major role in determining fold endurance when there were fewer number of folds; however, as the number of folds increased, the influence of interlaced abrasion became increasingly significant. Ultimately, these combined factors led to progressive damage evolution until failure occurred in the fabrics. Among all tested samples, the SiC fiber braided fabric with a higher braiding angle (α = 43.1°) demonstrated optimal fold endurance performance, and it had superior characteristics such as higher fold endurance numbers along with lower force loss rates for fiber tows after multiple folds and fabric force loss rates following repeated folds. [ABSTRACT FROM AUTHOR]

Pore defects are common defects in composites and can seriously affect the mechanical properties of composites. The present paper not only considers the pore defects, but also considers the influence of interface defects on the effective stiffness of 3D braided composites. A damage model is developed to predict the damage propagation of 3D braided composites considering pore defects. A multiscale simulation method using representative volume elements (RVE) combined with a micromechanical method and the finite element method is developed in this paper to meet the multiscale and periodic characteristics of 3D braided composites. The constituents at the microscale are composed of matrix, interface, fiber and pores, and the constituents at the mesoscale are composed of matrix, yarns and pores. The yarn at the microscale is homogenized by means of Mori–Tanaka model and extended double-inclusion model. The prediction and analysis methods of the existing models are compared with the experimental results to prove the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Several distinct Garside monoids having torus knot groups as groups of fractions are known. For n , m ≥ 2 two coprime integers, we introduce a new Garside monoid ℳ (n , m) having as Garside group the (n , m) -torus knot group, thereby generalizing to all torus knot groups a construction that we previously gave for the (n , n + 1) -torus knot group. As a byproduct, we obtain new Garside structures for the braid groups of a few exceptional complex reflection groups of rank two. Analogous Garside structures are also constructed for a few additional braid groups of exceptional complex reflection groups of rank two which are not isomorphic to torus knot groups, namely, for G 1 3 and for dihedral Artin groups of even type. [ABSTRACT FROM AUTHOR]

This paper focuses on investigating ablation characteristics of different nozzle materials in hybrid rocket motors by firing tests and numerical simulations. Hybrid rocket nozzles with different ablation materials are designed and manufactured. Four firing tests with working time of 40 s are conducted, and 90% hydrogen peroxide and polyethylene are adopted. The test results indicate that erosion rates of T705 graphite, whole felt C/C composite, axial rod braided C/C composite, and carbon/ceramic composite are 0.045 mm/s, 0.022 mm/s, 0.03 mm/s, and 0.01 mm/s. Circumferentially uneven ablation is found in the nozzle throat of T705 graphite and C/C composite, and this is mainly due to asymmetric oxidizer injection, asymmetric combustion, and uneven material properties. Transient numerical simulations of 40 s on nozzle thermochemical erosion are carried out, and the regression process of fuel wall and nozzle wall is solved by a dynamic grid technique. The error of average throat erosion rate between simulation results and test results is only 1.82%. The evolution process of nozzle profile and flow field structure are exhibited, and coupling effects between the erosion rate and nozzle profile are obtained. Simulation results show that as the working time increases, protrusions and pits appear on the nozzle inner wall and gradually extend. The temperature of nozzle wall and nozzle erosion rate on the windward side is higher, while they are lower on the leeward side. Nozzle throat erosion rate history is divided into four stages, and time nonlinear characteristics of the throat erosion rate are revealed. • 40 s firing tests of different nozzle materials are conducted. • Ablation properties of graphite, C/C composite and carbon ceramic are obtained. • Transient simulations of 40 s on nozzle thermochemical erosion are performed. • Simulation results agree with test data and evolution of nozzle profile is shown. • Time nonlinear characteristics of nozzle throat erosion rate are revealed. [ABSTRACT FROM AUTHOR]

Although there has been rapid advancement in piezoelectric sensors, challenges still remain in developing wearable piezoelectric sensors by a one-step, continuous and environmentally friendly method. In this work, a 1D flexible coaxial piezoelectric fiber was directly fabricated by melt extrusion molding, whose core and sheath layer are respectively slender steel wire (i.e., electrode) and PVDF (i.e., piezoelectric layer). Moreover, such 1D flexible coaxial piezoelectric fiber possesses short response time and high sensitivity, which can be used as a self-powered sensor for bending and vibration sensing. More interestingly, such 1D flexible coaxial piezoelectric fiber (1D-PFs) can be further endowed with 3D helical structure. Moreover, a wearable and washable motion monitoring system can be constructed via braiding such 3D helical piezoelectric fiber (3D-PF) into commercial textiles. This work paves a new way for developing 1D and 3D piezoelectric fibers through a one-step, continuous and environmentally friendly method, showing potential applications in the field of sensing and wearable electronics. [ABSTRACT FROM AUTHOR]

The mechanical properties of three‐dimensional (3D) braided composites are related to damage evolution. However, the multi‐scale damage mechanism of 3D braided composite shafts remains unclear. The main purpose of this article is to propose a shell‐based multiscale finite element model for effectively predicting the compressive and torsional properties of 3D four‐directional (3D4d) braided composite shafts. Considering the relation between equivalent ply angles and yarn structures, the multiscale model was developed based on a universal tubular unit cell. The equivalent ply angle was derived through the yarns' local braiding and horizontal orientation angles, and the elastic properties of each equivalent ply were derived through the stiffness averaging method. Both derivations were achieved by creatively utilizing deformation gradient theory and Nanson's formula from continuum mechanics. LaRC04 failure criteria and energy‐based damage evolution law were implemented to characterize the equivalent UD‐ply's damage behaviors. The proposed model was validated experimentally, and good agreements were observed between the failure morphologies and load–displacement curves of FEA and experimental results. The results show that the fiber tension and compression damages are the major failure modes of 3D4d braided composite shafts under compressive and torque loads, respectively. Finally, a parametric study was carried out and compared with that from other literature to clarify the meaning of this article in relevant studies. It provides an efficient and useful tool for the design and manufacturing of 3D4d braided composite shafts with desirable mechanical properties. Highlights: A shell‐based hierarchical multiscale model is developed for 3D braided composite shafts.An analyzing method is developed to investigate the tubular yarn structures.A large‐scale torsional experimental scheme is developed. [ABSTRACT FROM AUTHOR]

A positive braid is called tiny when it is a product of generators and each generator being used at most once. We will present a commuting criterion for tiny braids and explore the structure of the centralizer of a tiny braid in the set of positive braid monoids. We will also discuss various combinatorial properties of the centralizer and a few invariants of an associated commuting graph. Finally, we will provide affirmative answers to a couple of open questions related to the commuting graph of tiny braids. [ABSTRACT FROM AUTHOR]

This review is a critical analysis of the current state-of-the-art in core spun yarn textile triboelectric nanogenerators (CSY-T-TENGs) for self-powered smart sensing applications. The rapid expansion of wireless communication, flexible conductive materials, and wearable electronics over the last ten years is now demanding autonomous energy, which has created a new research space in the field of wearable T-TENGs. Current research is exploring T-TENGs made from CSYs as stable and reliable energy harvesters and sensing devices for modern wearable IoT platforms. CSY-TENGs are emerging as an important technology due to its simple structure, low cost, and excellent performance in converting mechanical energy into electrical energy and due to its sensing ability. This paper provides a critical review on current progress, it analyzes the unique advantages of CSYs T-TENGs over conventional T-TENGs, it describes fabrication techniques and discusses the materials used along with their properties and electrical performance characteristics, and it highlights the recent advancements in their integration with self-excitation circuits, charge storage devices and IoT-enabled smart sensing applications, such as environmental and health monitoring. In the conclusion, it discusses the challenges and future directions of CSYs T-TENGs and it provides a future road map for optimization, upscaling, and commercialization of the technology. [ABSTRACT FROM AUTHOR]

Liquid crystal elastomer fibers (LCEFs) are promising materials for constructing artificial muscles. However, the practical applications in smart wearable textiles and soft robots are still hindered due to their weak tensile performance and complex actuation integration. In this work, an LCEFs braided actuator is fabricated in which several LCEFs are integrated with silver‐plated nylon strands using the textile braiding method. The silver‐plated nylon strands can generate joule heat for triggering LCEFs and meanwhile strengthen the braided actuators. Owing to the braided structure, this LCEFs braided actuator exhibits large reversible contraction (34%) and actuation force (18.7 cN) with electrical stimulation at 0.6 V cm−1. An artificial arm and a soft pump based on the LCEFs braided actuators is successfully developed. The LCEFs braided actuator can lift 205 times its weight as an artificial biceps. And the soft pump can achieve cyclic contraction and relaxation motions similar to the cardiac muscle under electrical stimulation and reach an output flow rate of 111 µL s−1. This braided integration concept would broaden the potential applications of LCEFs. [ABSTRACT FROM AUTHOR]

Material flow and associated fiber orientation are among the most important features in Large Area extrusion deposition Additive Manufacturing (LAAM) of short fiber‐filled composites. Endeavors have been done in 2D flow models, where significant knowledge is achieved in explaining the material anisotropy of the deposited composite parts. Nevertheless, 2D flow models are limited by a couple of assumptions that lose significant characters of the deposition flow. This study is one of the first few that employ a 3D flow model which focuses on the quasi‐steady state of the polymer composite melt flow within the nozzle and the subsequent 90‐degree turning deposition onto the material substrate. The material flow is assumed as a highly viscous Newtonian flow. The fiber orientation is evaluated using the advanced pARD‐RSC fiber orientation tensor evaluation model, via the one‐way weakly‐coupled flow/orientation analysis formulation. Computed results show the fiber orientation state on the entire cross‐section of a deposited bead, which yields a clear view of how the material anisotropy is affected by the locally varied fiber orientation. The 3D‐flow prediction proves that the transverse directional fiber alignments are in high degree of similarity as compared to the over‐predicted results from the simplified 2D planar flows. In addition, the 3D‐model results exhibit a more favorable agreement with the reported experimental data than that yielded by the conventional 2D models. [ABSTRACT FROM AUTHOR]

Numerous process architectures for fabric molding are investigated because fiber braided structure is closely related to the performance of fiber‐reinforced composites. However, existing methods for calculating process architectures have to deal with the coordinates of each fiber when modeling the three‐dimensional braiding method without individually controlled switches. The amount of data grows geometrically as the number of fibers and braiding steps increases. A methodology that enables simple and efficient computation of a model of the relationship between braiding parameters and fiber structure is urgently needed. This paper proposes a novel algorithm to trace the yarn carrier trajectories through machine simulation with Euler rotation‐matrix operations. To predict the real fabric architecture, a contraction factor is introduced to optimize the yarn trajectory while considering the volume of the yarn. The optimized fabric architecture is explored and the braiding process architecture with different braiding parameters is simulated according to the algorithm. Based on the exploration of the relationship between the braiding parameters and the process structure, a hexagonal‐annular braiding machine was established, which can fabricate fabrics with different cross‐sectional shapes. The simulation results were verified by the braiding experiments. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer is an effective solution for replacing metal materials and achieving lightweight, and both three‐dimensional (3‐D) braided composites and prepreg laminated composites have their strengths and weaknesses. Using only one forming process can be challenging to meet the performance requirements of structural components under complex operating conditions. To effectively reduce the production cost and cycle time of large structural components while ensuring the mechanical properties of the structure, this article proposes a novel three‐dimensional braided and prepreg‐layered (braid‐and‐lay) composite forming process that is studied in the context of metro bogies. First, the performance advantages of braid‐and‐lay composites were verified through experimental methods. Then, a multi‐scale analysis method, combining experimental and finite element analysis, accurately predicted the macroscopic elastic parameters of the three‐dimensional braided composite with an error of less than 10% compared to the experimental values. Finally, a structural optimization design of the braid‐and‐lay composite metro bogie was carried out based on the predicted elastic parameters. The results show that the mass of the structure was reduced by 15.33%, from 272.103 to 230.386 kg, while ensuring that the displacement and stress responses do not exceed the constraint range. Highlights: Proposed a braid‐and‐lay integrated composite forming process.A multi‐scale analysis method, combining experimental and finite element analysis, was used to predict the modulus.The effect of braiding parameters on modulus prediction was investigated.The influence of the forming process and structural parameters on the performance of the metro bogie was investigated.The lightweight design of the metro bogie is effectively realized. [ABSTRACT FROM AUTHOR]

This study investigates the tensile and compression properties of three‐dimensional five‐direction (3D5D) braided composite circular tubes with preembedded titanium alloy licker‐ins. The influence of the braided angle, braided thickness, and braided configuration on the bearing capacity is analyzed, and the microdamage morphology and failure mechanism of the tube structure are examined using scanning electron microscopy. Results show that the 3D5D braided tube has a larger tensile failure load than the 3D full five‐direction braided tube of the same outer diameter. In circular tubes of the same braided configuration and outer diameter, the compression failure load increases with the wall thickness, and the C‐ø30t3 circular tube achieves the maximum compression failure load. The damage morphology is characterized by the pulling‐off failure of the licker‐in joint. The T‐ø30t2.5 and T‐ø25t3 circular tubes achieve a large failure load, with an average tensile load of over 120 kN. The failure morphology is characterized by the cracking of the fiber at the end of the tube after the licker‐in joint has been pulled off. The average tensile failure load of the T‐ø30t3 circular tubes is over 105 kN, and the failure morphology reveals a broken licker‐in joint, indicating design deficiencies that require further optimization. The findings of this paper can provide an important scientific basis for the lightweight and high‐strength connection design for 3D braided composites in near‐space aerostats and their flight applications. [ABSTRACT FROM AUTHOR]

This study investigates the impact of incorporating a triaxial woven fabric (TWF) into a unidirectional ply structure on the bending performance of the structure. The failure processes of the different ply structures were recorded using video analysis and acoustic emission. The experimental results indicated that incorporating a layer of carbon fiber TWF between the second and third layers (GGTGG) or between the third and fourth layers (GGGTG) of the four‐layer unidirectional fabric significantly improved the flexural strengths by 79.5% and 213.7%, respectively, and the flexural toughness by 480.3% and 324.8%, respectively. In addition, the incorporation of TWF in the structure resulted in a shift in the overall failure mode from brittle to ductile. When the TWF was closer to the lower surface of the sample, the crack was more uniform and the distribution range was wider. In contrast when the TWF was in the middle, the range of cracks generated by the sample was narrower. However, some of these cracks affected the stability of the material structure. Furthermore, the damage process was confirmed using images of crack growth and acoustic emission during the destruction process. This study provides valuable insights into enhancing the bending performance of unidirectional fiber layup in the non‐load direction. [ABSTRACT FROM AUTHOR]

This study aims to enable intelligent structural health monitoring of internal damage in aerospace structural components, providing a crucial means of assuring safety and reliability in the aerospace field. To address the limitations and assumptions of traditional monitoring methods, carbon nanotube (CNT) yarn sensors are used as key elements. These sensors are woven with carbon fiber yarns using a three-dimensional six-way braiding process and cured with resin composites. To optimize the sensor configuration, an artificial fish swarm algorithm (AFSA) is introduced, simulating the foraging behavior of fish to determine the best position and number of CNT yarn sensors. Experimental simulations are conducted on 3D braided composites of varying sizes, including penetration hole damage, line damage, and folded wire-mounted damage, to analyze the changes in the resistance data of carbon nanosensors within the damaged material. The results demonstrate that the optimized configuration of CNT yarn sensors based on AFSA is suitable for damage monitoring in 3D woven composites. The experimental positioning errors range from 0.224 to 0.510 mm, with all error values being less than 1 mm, thus achieving minimum sensor coverage for a maximum area. This result not only effectively reduces the cost of the monitoring system, but also improves the accuracy and reliability of the monitoring process. [ABSTRACT FROM AUTHOR]

Although 3-D braided composites can be incorporated with rotating central body-beam systems, there are currently few dynamic models for the rotating systems made of braided composites. This paper proposes a dynamic model of a 3-D 4-directional braided composite beam with a central rigid body. Based on the Timoshenko beam hypothesis, the displacements of the composite beam are described by the arc-length coordinate, and the displacement field is represented by the slope angle, tensile strain, and shear angle. The assumed mode method is employed to discrete the displacement field, and the dynamic model of the system is derived from the Lagrange equation. The equivalent stiffness matrices of 3-D 4-directional braided composite beams with different braiding angles are obtained using the volume average method. The influences of different angular velocities, braiding angles, and beam section parameters on the system's dynamic characteristics are studied. The model proposed in this study can be utilized to estimate the dynamic responses of braided composite blades, and lays the theoretical foundation for analyzing dynamic characteristics of anisotropic beams in engineering. [ABSTRACT FROM AUTHOR]

Fractures are crucial as main natural gas transport channels in tight sandstone reservoirs. In order to reveal the correlation between the combination of fractures in Block Keshen 2 and sandstone, we have collected drilling core data, logging curve data, imaging logging data, and rock thin-section data from the Bashjiqike Formation in the Keshen 2 area, and by classifying and statistically analyzing the different influencing factors of fractures, we have established a correlation between the development of fractures and sandstone thickness, lithology, and sedimentary microfacies. The results reveal the following: (1) frequent vertical superposition and lateral migration occur in the sedimentary sand bodies of the Bashijiqike Formation. Three types of patterns of sand bodies have been identified according to the changes in microfacies. Type I refers to the patterns of sand bodies developed in main subaqueous distributary channels, type II refers to the patterns of sand bodies developed in secondary subaqueous distributary channels or mouth bars, and type III refers to the patterns of sand bodies developed in isolated subaqueous distributary channels; (2) three types of fracture patterns have been described in the various sand bodies of the Bashijiqike Formation in the Keshen area, including high–medium-angle branch-like fracture patterns, medium-angle reticular fracture patterns, and isolated fractures; (3) the coupling relationship among sedimentary microfacies, sand body patterns, and fracture patterns has been established. The high–medium-angle branch-like fracture patterns mainly develop in the main underwater distributary channel and the type I sand body patterns. The medium-angle reticular fracture patterns mainly develop in the secondary underwater distributary channel and mouth bars, as well as the type II sand body patterns. Isolated fractures can occur in all sedimentary microfacies but are sporadically distributed within the three types of sand body patterns. The research results present the regularity of fracture development in fractured reservoirs, which can be applied to oil and gas fields with the same background, providing certain geological evidence for exploration and development. [ABSTRACT FROM AUTHOR]

Three-dimensional（3D） braided composite tubes, including 3D multi-layer braided, 3D fivedirectional surface-core braided, and 3D seven-directional braided tubes, were fabricated by vacuum assisted resin transfer molding. The yarn traces of the 3D braided composite tubes were systematically analyzed. The quasi‑static axial compression tests were carried out to investigate the effects of different braiding processes on the compression bearing capacity, failure mode and energy absorption performance of three‑dimensional braided composite tubes. The results showed that the axial bearing capacity and failure mechanism of circular tubes with different braided structures were significantly different. 3D multi‑layer braided tubes maintained a high volume content of circumferential yarn, which can effectively bear the axial load, making its axial bearing capacity significantly higher than the other two types of braided circular tubes. However, due to the weak load transfer performance between fibers, brittle failure was easy to occur, resulting in the worst energy absorption effect. 3D five‑directional surface‑core braided and 3D seven‑directional braided tubes had closely interwoven yarn structures，and the radial braided yarn can effectively limit the shear crack growth, thus leading to gradual and stable flowering failure. Such failure had better energy absorption characteristics. The fiber of the 3D five‑directional surface‑core braided tube broke more fully, and the energy absorption effect was the most excellent. [ABSTRACT FROM AUTHOR]