Properties Of Fibrous Materials Research Articles

Optimization of fiber reinforced lightweight rubber concrete mix design for 3D printing

A novel lightweight insulation concrete for 3D concrete printing is developed in this study, which incorporates crumb rubber (R) as a modifier to achieve low density, exceptional thermal insulation properties, and high ductility. The mechanical properties and fiber reinforcement mechanism of lightweight rubber aggregate concrete (CR) are investigated under varying R substitution rates, encompassing compressive strength, flexural strength, tensile strength, and tensile strain of CR. The thermal conductivity test offers insights into the thermal insulation mechanism of CR. The study investigates the compatibility between the material properties of fiber reinforced rubber concrete and the parameter matching of concrete printing equipment, as well as explores the relationship between interlayer bond strength and material composition. The optimal water-binder ratio for 3D printed fiber-reinforced lightweight rubber concrete compatible with printer equipment is determined through fluidity experiments and buildability tests. The findings indicate a statistically significant decrease in CR density by 16.5% when the replacement rate reaches 30%. Although the mechanical strength of CR decrease with the increasing substitution rate of R, the tensile strain showe an increasing trend. The addition of glass fiber reinforcement resulted in a notable enhancement of the mechanical properties and a significant increase in tensile strain for CR. In addition, CR thermal conductivity is reduced by 20.65%, with the excellent thermal insulation performance. This study is of great significance to promote the rational utilization of rubber resources, promote the development of circular economy, and build a conservation-oriented and environment-friendly society.

On the Micro-Stress Fields in Fibre-Hybrid Polymer Composite Laminae with Periodic Microstructure Under Transverse Tension and Transverse Shear Loading

AbstractThis paper investigates the effect of intra-laminar fibre hybridisation, i.e., primary and secondary fibres within a matrix, on the homogenised properties and micro-stress fields in uni-directional polymer composite laminae. The study is focused on S-glass/epoxy laminae which are hybridised with secondary fibres (e.g., polypropylene). Two-dimensional repeating unit cells (2D RUCs) with periodic microstructures are developed to conduct the micro-mechanical analyses under transverse tensile and transverse shear loading conditions. Uni-directional fibre-hybrid S-glass/epoxy laminae with different secondary fibres are studied by varying (a) the periodic microstructure and (b) the material properties of the constituent fibres to assess the effect of such geometric and material variations on the homogenised elastic lamina properties and intra-lamina micro-stress fields. The results show that intra-laminar fibre hybridisation significantly affects the elastic lamina properties and micro-stress fields. Notably, the presence of the secondary fibres significantly increases or reduces the stress fields in the matrix and at the fibre-matrix interfaces (i.e. normal and shears stress components)–depending on the microstructure and the stiffness of the secondary fibres–which could be explored to manipulate the damage modes and thus energy dissipation mechanisms.

Vibration analysis of bio-inspired sandwich composite beam under rotating environment based on the Internet of Things technology

Sandwich composite materials with corrugated cores are mostly used in industries like aircraft, marine construction, automobiles, and construction. Sandwich composite constructions are made for their lightweight, high strength, and high stiffness, and also the sandwich core composite structures are useful for dynamic studies. A novel design inspired by a woodpecker beak microstructure creates fillet edge and champer edge designs. This novel design motivates us to achieve the energy absorbing results starting with free vibration studies followed by rotating environment vibration studies. ASTM E1876 standards, a non-destructive approach, are used to determine the material properties of carbon fiber-polylactic acid (CF-PLA) and glass fiber reinforced polymer (GFRP), along with alternative dynamic method (ADM) for core property evaluation. The hand lay-up technique is used for fabrication and evaluated for free vibration testing with appropriate boundary conditions. Internet of Things technology has been used for analyzing vibrations of sandwich structures in rotating environment setup with 250, 500, 750, and 1000 rpm. It was observed that the fillet edge pattern has a more efficient natural frequency than the champer edge pattern. Furthermore, the parametric evaluations were performed in various ply configurations in numerical simulations for free vibration and the rotating Environment. Also, the effective results are seen in fillet core bioinspired sandwich structure that achieves efficient stiffness in both free vibration and rotational environments, despite various boundary conditions and parametric circumstances. Therefore, the fillet edge 3D printed core design with particular GFRP factsheet orientation brings out the novelty of this research.

Effect of fiber volume and material property and nucleus pulposus area on intervertebral disc mechanical behavior

The material properties and volume proportion of the fibers as well as the cross-sectional area proportion of nucleus pulposus vary greatly in different studies. The effect of these factors on the mechanical behavior of intervertebral discs (IVDs) are uncertain. The IVDs finite element models with different parameters were created to investigate the pressure, height, rotation, stress, and strain of the IVDs under loads: pure compression, rotation after compression or axial moment after compression. The results showed that the material properties of fibers had great impact on the mechanical behavior of IVDs, especially on the rotation angle. When the fiber volume ratio was small, its changes had a significant impact on the rotation angle of the IVDs. The area proportions of nucleus pulposus had relatively little effect on the mechanical behavior of IVDs. The IVDs rotation should be observed when validating the model. By adjusting the elastic modulus or volume ratio of fibers within a reasonable range, a model that could simulate the mechanical behavior of normal IVDs could be obtained. It was reasonable to make the area proportion of nucleus pulposus within 25%-50% for the IVDs finite element model. This study provides guidance and reference for finite element modeling of the IVDs and the investigation of the IVDs degeneration mechanism.

Recent advancements in polyoxometalate-functionalized fiber materials: A review

Abstract The development of advanced composite materials based on polyoxometalates (POMs) and fibers has attracted significant attention due to their combination of the unique chemical reactivity of POMs and the flexible wearable properties of fiber materials. The exceptional properties exhibited by those resultant composites have been widely employed in catalysis and optical sensors. In this article, we aim to provide an overview of progress on POMs functionalized fiber materials involving the preparation methods, namely, electrostatic spinning and layer-by-layer self-assembly methods, as well as the developments in the fields of catalysis, photochromism, and photoluminescence. Current applications are critically assessed and promising future target systems are discussed.

Vibration characteristics of pre-twisted rotating Ti-SiC composite airfoil blade

In this paper, a pre-twisted blade model is established based on the FSDT (first-order shear deformation theory), where the Ti-SiC fiber reinforced composite and NACA 4-digit airfoil are innovatively proposed. Rayleigh-Ritz method is utilized to deduce the pre-twisted blade natural frequencies and mode shapes where the exponential polynomials satisfying the cantilever boundary conditions are taken as admissible functions. Comparing with the existing literature, the precision of the model and the method is verified. The material properties of Ti-SiC fiber reinforced composites are calculated by the M-T (Mori-Tanaka) method and FE (Finite Element) method to guarantee the reliability of the calculation method. In addition, the parameters affecting blade vibration, such as rotating speed and aspect ratio, are studied in detail. The research findings indicate that the addition of SiC fibers enhances the properties of the composite blade, and then improves the frequency of the rotating blade. Additionally, the pre-twisted angle, rotating speed, aspect ratio and blade shape significantly affect the natural frequency of Ti-SiC composite airfoil blade. The well-established model accurately predicts the dynamic behaviors of the rotating blade, which has certain guiding value for the optimization of blade material and geometric size.

Understanding the material properties of alkali-treated lignocellulose fiber obtained from high-altitude Lokta bushes

Understanding the material properties of alkali-treated lignocellulose fiber obtained from high-altitude Lokta bushes

Failure mechanism of bonding between natural fiber and cement matrix at high temperature

The debonding behavior of natural fibers with cement matrix at elevated temperatures has been investigated by introducing a new test method for measuring the interfacial shear strength between the fibers and the cement matrix in the field of cementitious composites research. In addition, the effects of shrinkage, surface roughness, and tensile strength changes of natural fibers on the interface at high temperatures were analyzed by characterizing the failure process of chemical bonding with the matrix due to changes in the surface functional groups of natural fibers. The results show that the bonding properties between natural fibers and the cement matrix gradually decrease with increasing temperature, which is due to the contraction of the natural fibers in the radial direction at high temperatures leading to debonding with the cement matrix on the one hand, and the degradation of chemical bonding enhancement due to the reduction of polar groups on the surface of the fibers on the other hand, which contributes to the reduction of the interfacial strength between the fibers and the matrix. In the post-high-temperature phase, the temperature dependence of the inherent material properties of the natural fibers leads to a decrease in the mechanical properties as an additional factor affecting the interfacial behavior. This work evaluates the durability of natural fibers in cement matrices under high temperature conditions from the viewpoint of their inherent physical properties and surface chemical properties, providing unique research ideas and insights for related studies. Meanwhile, a new experimental method is introduced in the field of fiber-reinforced cementitious composites interface research, which can be widely attempted to be used in the study of selective combinations of different fiber-matrix interfaces, fiber size selection, and fiber modification to optimize the overall performance of the composites, which is of great significance to the research in this field.

Электрохимические сенсоры на основе сеток из однослойных углеродных нанотрубок для вольтамперометрического определения аскорбиновой кислоты

Modern highly sensitive and selective sensors are able to determine biologically active substances, which makes this direction one of the most popular areas of analytical chemistry. The study featured the electrochemical properties of new fiber materials based on single-wall carbon nanotubes with prospects of using them in the voltammetry of ascorbic acid. 
 The authors developed a new technology to synthesize films from disordered single-wall carbon nanotubes by chemical vapor deposition. Fibers were produced from a solvent by wet-pulling of single-wall carbon nanotubes networks. Thin films of randomly oriented single-wall carbon nanotube bundles were deposited downstream of a floating aerosol CVD reactor, which included a high temperature furnace with a quartz tube. The synthesis of the single-wall carbon nanotube samples was performed at 825°C. Ethanol served as carbon source while ferrocene was used as catalyst precursor. The single-wall carbon nanotubes were collected on a nitrocellulose filter in the form of films with transmittances of 10% in the middle of the visible wavelength (550 nm). The method was optimized to involve air annealing at 300–320°C and a treatment with strong inorganic acids, i.e., HCl, HNO3 + H2SO4. The voltammetric curves recording included background electrolyte, scan rate, and preconditioning. These parameters were selected experimentally to obtain the maximal sensor response to ascorbic acid content. The anodic peak of ascorbic acid in the phosphate buffer electrolyte (pH 6.86) was observed at a potential of +0.2 V. The current and peak area of ascorbic acid oxidation depended neither on the time nor on the conditioning potential of the sensor. The linear dependences of these parameters on the concentration of ascorbic acid stayed within 50–500 μmol/L (8.8–90 mg/L) at a scan rate of 0.1 mV/s. The single-wall carbon nanotube microsensor had a length of 0.5 cm and an average width of 400 μm. Its sensitivity was two times as high as that of a disk glassy carbon electrode with a diameter of 5 mm. 
 The experimental sensors proved effective in determining ascorbic acid in food products, pharmaceuticals, and biological fluids.

Experimental investigation on the flexural behavior of concrete reinforced by various types of steel fibers

The benefit of steel fiber on the mechanical behaviors of concrete has been well accepted. The flexural behavior of steel fiber reinforced concrete (SFRC) is complicated which depends on many factors, such as matrix properties, fiber material properties, fiber geometries, fiber volume contents, and interface properties. Thus, the investigations on the flexural behavior of SFRC are needed to be expanded. In this study, the effects of fiber type with varying shapes and aspect ratios on the flexural performance of SFRC were investigated. Five steel fibers were adopted in this study: milled fiber (M), corrugated fiber (C) and three hooked fibers with aspect radios of 45 (HA), 55 (HB), and 65 (HC). Two volume fractions (0.4% and 1.0%) of steel fiber and two compressive strengths (normal and high strengths) of matrix were considered. The load-deflection curves, energy absorption capacity and equivalent flexural strength were discussed. The results show that the flexural behavior of SFRC beams reinforced by 1.0% fibers is significantly higher than that of the beams reinforced by 0.4% fibers. Hooked fiber reinforced beams performed the best flexural load-deflection response compared to the beams reinforced by milled fiber and corrugated fiber reinforced, and exhibited an increasing trend of flexural performance as the fiber aspect ratio increased. The differences between specimens with different fibers for high strength matrix are more obvious compared to the normal strength matrix.

A pressure- temperature microsensor based on synergistical sensing of dual resonators

Simultaneous measurements of pressure and temperature take wide attentions for several technical applications. This pressure–temperature microsensor fully utilizes the mechanical and thermal features of common semiconductor materials which can be achieved by micro-electro mechanical technologies, in contrast to typical simultaneous measurement systems that rely on optical properties of fiber materials. The idea is illustrated using two identical resonators that work synergistically to sense the pressure and temperature. The pressure and temperature sensing are determined by the reactions of pressure sensitive diaphragm to pressure and the differences in the coefficients of thermal expansion among the composed materials of the microsensor, respectively. The pressure and temperature sensitivity of the dual resonators in this work were calculated by numerical simulations and verified by experimental characterizations. Additional characterizations revealed that the measurement pressure and temperature errors of the developed microsensor were within −10 Pa to 40 Pa and −0.25℃ to 0.26℃ with corresponding accuracy of ± 0.01 %FS (Full scale) and ± 0.2 %FS, respectively.

Improving Recycled Paper Materials through the Incorporation of Hemp, Wood Virgin Cellulose Fibers, and Nanofibers

A significant increase in the consumption of recycled fiber products has been observed worldwide, and the industry is forced to solve the challenges of recycled fiber quality and add strength agents and/or virgin fibers to reach sufficient properties. In order to investigate whether the mechanical and air permeability properties of waste fiber (WF) material can be significantly improved by adding wood kraft fibers (KF), hemp soda fibers (HF), and ammonium persulfate oxidated cellulose nanofibrils (CNF), different fiber blends were prepared and tested. Results revealed the excellence of hemp fibers over wood fibers regarding the improvement of WF products. The results of WF after the addition of 10% mixed fibers (KF + HF) were higher than the results of a 50% KF addition. The impact of CNF depended on fiber composition and properties. A formula for modeling the CNF impact on different fiber compositions was proposed. Obtained fiber material samples showed suitability for home composting, thus contributing to the goals of the European Green Deal regarding reducing landfill waste and the development of cleaner products.

Unique Material Properties of Bombyx mori Silk Fiber Incorporated with 3-Azidotyrosine.

Silk fiber produced by the silkworm Bombyx mori is a nature-derived proteinous fiber with excellent mechanical strength and broad biocompatibility. To alter its material properties and make it more suitable for textile, biomedical, and electronics applications, chemical modifications and genetic engineering methods have been extensively studied. Here, we report that the translational incorporation of a synthetic amino acid, 3-azidotyrosine (3-AzTyr), into B. mori silk fiber can improve its material properties. Such an incorporation considerably increased the fiber's mechanical strength and remarkably changed its solubility, whereas its crystalline hierarchical structure was not perturbed, as shown by X-ray analyses. These changes were probably caused by the intra- and/or intermolecular crosslinkings involving the azido group of 3-AzTyr during the degumming process to remove a coating protein. These findings indicate that the incorporation of synthetic amino acids could be an efficient method to improve the properties of silk-based materials.

Global sensitivity analysis of complex moduli of carbon fiber reinforced polymer

AbstractGlobal sensitivity analysis of complex moduli of carbon fiber reinforced polymer (CFRP) is performed by using variance‐based sensitivity analysis. Twelve material properties of matrix and fiber are selected as input arguments, including fiber volume fraction, three matrix properties, and eight carbon fiber properties. Ten thousand samples are generated with Sobol sequence. Based on the correspondence principle, six complex moduli of unidirectional CFRP, and two complex moduli of quasi‐isotropic laminate, orthogonal laminate, and symmetric laminate with different fiber angles are predicted using the generalized method of cells and classical laminate theory. The sensitivity indexes of all input arguments are calculated. The results show that the loss factors of CFRP are mainly affected by the matrix loss factor and fiber axial loss factor, and slightly affected by the fiber transverse loss factor.Highlights Sensitivity analysis reveals key factors influencing CFRP complex moduli. Impact of fiber and matrix properties on CFRP damping revealed. Insights for high‐damping and high‐stiffness CFRP development. Enhanced understanding of energy absorption mechanisms. Uncovering the dominant role of matrix and fiber axial properties in damping.

Thermally responsive copper alginate/nano ZnO/quaternary ammonium chitosan triple antimicrobial fiber

Smart and controllable antibacterial fabrics have enormous potential in the textile, medical, and healthcare fields. In this study, nano zinc oxide (ZnO) was synthesized in situ in sodium alginate (Alg) solution, and the above-mentioned solution was combined with quaternary ammonium chitosan (QAC) to form a polyelectrolyte spinning solution. A composite antimicrobial fiber with thermally responsive properties was created by wet spinning through CuCl2 coagulation bath crosslinking and in-situ synthesis of CuS on the fiber surface. Benefitting from the mixed-solubility synergistic effect of Alg and QAC, the mechanical properties of composite fiber materials were greatly improved. The tensile strength of the fiber was 58 ± 1.5 MPa, while the fiber material maintained good biocompatibility, moisture absorption, air permeability, and antibacterial properties. Adding a CuS layer gave the composite fibers photothermal response-ability and further promoted the controllable antibacterial properties of the materials. The maximum rings of inhibition of the copper alginate/nano ZnO/quaternary ammonium chitosan/ copper sulphide (CAlg/ZnO/QAC/CuS) composite fiber against S. aureus, E. coli and P. aeruginosa were 2.9 mm, 2.5 mm and 2.2 mm respectively. This was attributed to the synergistic effect of the inorganic and organic antimicrobial agents of nano ZnO and QAC component as well as the thermal stimulation response of CuS. These characteristics of the smart responsive composite fibers indicate their potential applications in medical dressings, special textiles, and healthcare materials.

Multiscale theoretical model shows that aging-related mechanical degradation of cortical bone is driven by microstructural changes in addition to porosity

This study aims to gain mechanistic understanding of how aging-related changes in the microstructure of cortical bone drive mechanical consequences at the macroscale. To that end, cortical bone was modeled as a bundle of elastic–plastic, parallel fibers, which represented osteons and interstitial tissue, loaded in uniaxial tension. Distinct material properties were assigned to each fiber in either the osteon or interstitial fiber “families.” Models representative of mature (20–60 yrs.) bone, and elderly (60+) bone were created by modeling aging via the following changes to the input parameters: (i) increasing porosity from 5% to 15%, (ii) increasing the ratio of the number of osteon fibers relative to interstitial fibers from 40% to 50%, and (iii) changing the fiber material properties from representing mature bone samples to representing elderly bone samples (i.e., increased strength and decreased toughness of interstitial fibers together with decreased toughness of osteon fibers). To understand the respective contributions of these changes, additional models isolating one or two of each of these were also created. From the computed stress–strain curve for the fiber bundle, the yield point (ϵy, σy), ultimate point (ϵu, σu), and toughness (UT) for the bundle as a whole were measured. We found that changes to all three input parameters were required for the model to capture the aging-related decline in cortical bone mechanical properties consistent with those previously reported in the literature. In both mature and elderly bundles, rupture of the interstitial fibers drove the initial loss of strength following the ultimate point. Plasticity and more gradual rupture of the osteons drove the remainder of the response. Both the onset and completion of interstitial fiber rupture occurred at lower strains in the elderly vs. mature case. These findings point to the importance of studying microstructural changes beyond porosity, such as the area fraction of osteons and the material properties of osteon and interstitial tissue, in order to further understanding of aging-related changes in bone.

Investigating the material properties of hemp fiber and puffed rice for use in heritage conservation

A nation’s customs and traditions are unique, including the appearance of its buildings. Restoring older buildings retains cultural connections and enhances sensitivity to the past. Conservation process materials must be distinguishable from originals for easy removal or change while matching features, a challenging task. The goal is to adopt materials similar in texture, scale, color, and form to the original. The increasing need for a sustainable environment attracts the scientific community towards alternative natural materials instead of traditional ones, adopting ecological principles. Eco-friendly materials from agricultural waste are less polluting. Bio-based materials, like hemp and rice, offer good thermal properties and replace traditional materials. Some are commercialized, while others are in the early production stages. Application conditions and potential adoption in heritage building conservation still need to be studied. Gaps in existing knowledge are addressed by assessing biomaterials’ physical properties in various conservation scenarios. Comparative analysis between new and conventional materials identifies vital advantages. The analysis also determines characteristics like thermal resistance, fire resistance, color, texture, environmental and health impact, and the production process. Findings indicate outstanding performance and can be developed in various colors and textures, essential for preserving the original structural appearance.

Data driven statistical method for the multiscale characterization and modelling of fiber reinforced composites

Multiscale analysis of composite laminates allows for predicting the mechanical response of these materials avoiding cumbersome experimental campaigns. The matrix and fibre material properties and the size of the Representative Volume Element (RVE) are the main parameters affecting the accuracy of multiscale models. This paper proposes a statistical inverse method to calibrate micromechanical material parameters from macroscale experiments and 3D reconstruction. First, glass fiber reinforced epoxy laminates have been analysed with Computer Tomography (CT), then, the material 3D microstructure has been reconstructed and fibre, matrix, and voids were segmented. Tensile tests have been performed on the composite specimen, measuring the surface strains with a Digital Image Correlation (DIC) system. The reconstructed volume, converted to a voxel mesh, has been used to compute the homogenized response of composite by Fast Fourier Transform (FFT) analysis. By comparing the marginal distribution of homogenized material stiffness extracted from DIC data of tensile tests, with the conditioned distribution computed by varying the FFT model parameter, a Stochastic Volume Element (SVE) is finally calibrated. A probabilistic multiscale model based on the SVE that propagates the uncertainty from the microscale to the structure level is presented.

Recent Advances in Ballistic Resistance of Lightweight Metal Sandwich Cores

Sandwich construction has proven to be an excellent low-density multifunctional design for a wide range of applications in ballistic protection, energy absorption, and thermal insulation. Based on the bulletproof effect of each layer of the sandwich structure, this paper expounds and summarizes the material properties that can be used as each layer. The mechanical and ballistic properties of ultra-high strength aramid (Kevlar) and ultra-high molecular weight polyethylene (UHMEPE) composites and the ballistic properties of mixed fibers of these two materials versus the mechanical properties of single fiber materials, the mechanical properties, chemical stability and other properties of aluminum and magnesium alloys, the effects of heat treatment and coating treatment on the ballistic properties of aluminum alloys, and finally the energy absorption properties of several common core materials structures are compared.

Stability analysis of hybrid laminated cylindrical shells reinforced with shape memory fibers

Laminated composite structures are widely used in various industries. Body and cape of high-speed flight vehicles are exposed to aerodynamic heating so that causes thermal buckling and dynamic instability. Shape memory alloys (SMAs) have extraordinary mechanical and physical properties which made them suitable for application in laminated structures. In this paper, stability analysis of hybrid laminated cylindrical shells reinforced with SMA fibers is investigated. Utilizing the principle of virtual displacement, governing equations and associated boundary conditions are determined based on the first-order shear deformation theory of shells considering Von- Kármán form of geometrical non-linearity and Love's first approximation. Material properties of SMA fibers and composite vary due to temperature. Variation of thermo-mechanical properties for SMA fibers due to uniform change of temperature are determined through the one-dimensional form of Brinson's constitutive law. Also, different types of loading conditions consist of axial load, pure lateral pressure and hydrostatic pressure are considered. Eventually, the effect of material properties, boundary supports and temperature on the critical buckling axial load, pure lateral pressure and hydrostatic pressure of the laminated cylindrical shells are studied. Investigations indicate that volume fraction and pre-strain of SMA fibers have significant effect on the stability of the laminated cylindrical shells.