Fiber Composite Materials Research Articles

Application of Bamboo Composite for Unmanned Aerial Vehicle Rod Structure

Researchers are exploring the use of natural fibers, such as bamboo fibers, as a replacement for synthetic fibers in composite materials due to environmental concerns and rising costs. Bamboo fibers have several benefits, including low cost, biodegradability, light weight, and good mechanical qualities. This study focused on the mechanical and physical characteristics of bamboo fiber composites for drone structures. Tensile tests were conducted, revealing a relatively low tensile strength ranging from 22026.99 to 5474.92 N/𝑚𝑚3 compared to carbon fibre composites. The tensile strength was influenced by the composition and ratio of bamboo fibre and epoxy. The density of the bamboo fibre composite ranged from 0.9720 to 0.7790 g/c𝑚𝑚3, which is lower than carbon fibre composites. Increasing the bamboo fibre content resulted in a decrease in density.

Influence of surface roughness on the mode II fracture toughness and fatigue resistance of bonded composite-to-steel joints

Hybrid bi-material concepts in engineering structures where fibre-polymer composites are used together with steel structural members have potential to reduce material usage, extend fatigue life and improve structural reliability. The bond performance of the bi-material composite-to-steel interface is of crucial importance and highly relies on the surface preparation quality of the steel element. This paper investigates the influence of steel surface roughness on the mode II fracture toughness and fatigue crack growth behaviour of the bonded composite-to-steel joints. Glass fibre composite and mild structural steel material is considered directly bonded in a wet lay-up process. 4-point end notch flexure (4ENF) tests are conducted on specimens with the steel plates prepared with low, medium and high roughness, respectively. In addition, morphology of the fracture surfaces are characterised by a 3D profilemeter and the friction coefficient is measured by a tribometer for each roughness level. Results show that in quasi-static fracture, fibre bridging is dependent on the surface roughness. A roughness level with Sq ≥ 22 µm of the steel surface can promote significant fibre bridging thus improved fracture toughness due to enlarged effective bonding area. Under cyclic loading, no fiber bridging is observed across all roughness levels tested. However, the Paris curve parameter C is significantly affected by the roughness level, which decreases by approximately 100 times as the steel surface roughness increases from the low level of Sq = 5 µm to high level of Sq = 22 µm. The m parameter of the Paris curve remains fairly constant across all the roughness levels tested.

Thermal Insulation Properties and Simulation Analysis of Foam Concrete Regulated by Mechanical and Chemical Foaming.

To address, mitigate, or prevent thermal environmental issues arising from the heat dissipation of high-temperature surrounding rocks in deep hot tunnels, a research proposal is put forward based on previous studies and the team's initial experiments. The proposal involves using mechanical and chemical foaming to enhance the thermal insulation properties of foamed concrete, and this will be tested through engineering verification. Different proportions of cementitious materials, latex powder, polypropylene fiber, and self-made composite foam materials were designed using an orthogonal approach for testing the macroperformance and microstructure of foamed concrete. The pore structure of foamed concrete was quantitatively analyzed by Image-Pro Plus 6.0 software, and a fitting expression was established between thermal conductivity and the number of pores (1-2 mm). Characteristics of heat transfer inside the foam concrete were simulated and analyzed using COMSOL software, and the transmission path of heat streamline was found to be ″concave-convex form″, illustrating the blocking effect of foam concrete on heat. A thermal insulation engineering model was created using Fluent software to investigate the effects of thermal insulation layer thickness, water gushing heat release, seasonal factors, and other working conditions on the airflow temperature in the roadway before and after the application of foam concrete. The simulation results demonstrate that foam concrete can effectively reduce the airflow temperature in the roadway and weaken the surrounding rock heat dissipation. Additionally, it is found that the decreasing rate of heat dissipation of surrounding rock increases with the increase of insulation layer thickness, proving the engineering applicability of foam concrete for roadway insulation. The research results provide a theoretical basis and practical guidance for heat damage control of deep mining roadway.

Selecting sustainable fibers for composite materials

Jussi Roto, sourcing manager for materials and technology at Finnish composites manufacturer Exel Composites, explains the vital role that fiber selection plays in sustainable composites production.

Aramid Fiber Composites for Sporting Equipment: Exploring Preparation Methods and Mechanical Properties

This study investigates the novel utilization of aramid fiber composite materials in sports equipment, elucidating their mechanical properties and development processes. Aramid fibers, despite their relatively brief 30-year existence in the materials realm, have emerged as pivotal elements in composite material research. Their exceptional traits, including high tensile strength, resistance to corrosion, impact resilience, pliancy, and effective thermal insulation, have rendered them pivotal in diverse applications, particularly in sports equipment. This research delves into the meticulous preparation methods of aramid fiber composites and comprehensively analyzes their mechanical attributes. Experimental findings ascertain a direct and proportional relationship between the tensile strength of these composites and the surface density of the fabric. Moreover, investigations into impact strength and wear rate, particularly at a 10% aramid fiber content, showcase optimal performance under varying temperature conditions. This study accentuates the immense potential of aramid composites in elevating the performance and durability of sports equipment, thereby paving the way for significant advancements in this domain.

Bulk Schottky Junctions-Based Flexible Triboelectric Nanogenerators to Power Backscatter Communications in Green 6G Networks.

This work introduces a novel method to construct Schottky junctions to boost the output performance of triboelectric nanogenerators (TENGs). Perovskite barium zirconium titanate (BZT) core/metal silver shell nanoparticles are synthesized to be embedded into electrospun polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) nanofibers before they are used as tribo-negative layers. The output power of TENGs with composite fiber mat exhibited >600% increase compared to that with neat polymer fiber mat. The best TENG achieved 1339V in open-circuit voltage, 40µA in short-circuit current and 47.9Wm-2 in power density. The Schottky junctions increased charge carrier density in tribo-layers, ensuring a high charge transfer rate while keeping the content of conductive fillers low, thus avoiding charge loss and improving performance. These TENGs are utilized to power radio frequency identification (RFID) tags for backscatter communication (BackCom) systems, enabling ultra-massive connectivity in the 6G wireless networks and reducing information communications technology systems' carbon footprint. Specifically, TENGs are used to provide an additional energy source to the passive tags. Results show that TENGs can boost power for BackCom and increase the communication range by 386%. This timely contribution offers a novel route for sustainable 6G applications by exploiting the expanded communication range of BackCom tags.

Tailoring fractal structure via 3D printing to achieve flexible stretchable electrodes based on Ecoflex/CNT/CF

Flexible electrodes are crucial for the widespread application of flexible electronics. Flexible stretchable electrodes are a research hotspot for finding a solution for the inability of flexible electrodes to withstand large deformations. In this study, the suitability of silicone rubber (Ecoflex), carbon nanotube (CNT), and carbon fiber (CF) composite materials for flexible devices and their ratios were evaluated for the first time. 3D-printed electrodes based on fractal structures with tensile insensitivity and high linearity were prepared to achieve integrated stretching of flexible devices. To demonstrate the benefits and impact of fractal structures on electrode performance, we fabricated flexible stretchable electrodes with four distinct designs: horseshoe, U-shaped, rectangular, and triangular. The tensile properties of these structures were theoretically calculated and validated through simulations and experiments; the horseshoe design proved to be the softest. Furthermore, we evaluated the performance of the prepared third-order flexible stretchable electrodes for gas-detection applications and achieved promising results, demonstrating the significant potential of these electrodes for wearable gas detection.

Beyond Symmetry: Exploring Asymmetric Electrospun Nanofiber Membranes for Liquid Separation

AbstractComposite membranes with asymmetric traits have gained attention in liquid separation, featuring gradient chemical and physical attributes that align or oppose mass transfer direction. Chemically asymmetric configurations harness internal driving forces to heighten separation efficiency, rendering them an appealing option for heightened separation efficiency and fouling prevention. Concurrently, the internal hierarchical structure differences within composite membranes—such as fiber‐based structural adjustments and the gradient density of functional layers—yield the dual benefits of effective liquid repelling and heightened transport efficiency. Unlike conventional phase‐change methods, electrospinning technology possesses advantages in constructing and governing composite fibrous membrane materials with asymmetric chemistry and hierarchical structures, driven by its adaptable stacking methodologies. Notably, the inherent pore structure of electrospun nanofibrous membranes emerges as a proven solution for minimizing transport resistance. In recent times, interest has surged in electrospun nanofibrous membranes endowed with internal asymmetric properties. However, the spotlight has predominantly graced Janus membranes, spotlighting opposite wettability on different sides, leaving other facets of asymmetric membrane enhancement somewhat underexplored. This comprehensive work unveils recent strides in design, fabrication, facilitated transport mechanisms, and real‐world liquid separation applications, all under the aegis of electrospun nanofiber membranes, each endowed with distinct asymmetric properties.

Stability of cylindrical anisotropic composite shells under torsion in a three-dimensional formulation

The article presents a calculation of the stability of non-thin cylindrical anisotropic layered shells under the action of end torsional moments in a spatial formulation. The anisotropy of the used material is characterized by one plane of elastic symmetry of characteristics. This is caused by the mismatch between the main elastic directions of the composite fibrous orthotropic material and the axes of the curvilinear cylindrical coordinate system.
 A three-dimensional inhomogeneous system of partial differential equations describing the subcritical stress-strain state within the linear theory of elasticity is derived using the Hu-Washizu variational principle. Reducing the dimension of the problem under consideration from three-dimensional to one-dimensional is carried out by taking into account the axial symmetry of the deformation of the cylindrical shell and using the method of straight lines along the generatrix.
 Based on the modified Hu-Washizu variational principle, a three-dimensional system of homogeneous partial differential stability equations is derived within the framework of the spatial theory of elasticity. The reduction of a three-dimensional system to a one-dimensional one is carried out along the generatrix and in the circular direction - by expanding the components of stresses and displacements into double trigonometric series when applying the procedure of the Bubnov-Galorkin method, as well as taking into account the periodicity of the resolving functions.
 An algorithm has been developed, implemented in the form of application software packages for PCs. In it, in a single computational process using the numerical method of discrete orthogonalization in the direction normal to the middle surface of the shell, the establishment of the parameters of the subcritical stress-strain state and the solution on this basis of stability problems for non-thin anisotropic cylindrical shells under the influence of torsion are combined.
 The problem of the influence on the stability of an anisotropic cylindrical non-thin shell of an increase in the number of cross-reinforced layers depending on the angle of rotation of the main directions of elasticity of the material and the direction of application of torque is considered. The obtained results of stability calculations according to the proposed approach were compared with critical torsion loads calculated using an orthotropic model for calculating anisotropic shells. It is shown that for single-layer cylindrical shells the difference between the compared results reaches 69%. An increase in the number of cross-reinforced layers leads to a decrease in this discrepancy, and with seven to eight layers, the difference between the critical loads obtained using the described approach and the orthotropic model is within 5%. This result is consistent with those obtained using classical or refined theories of calculations of both thin and non-thin anisotropic cylindrical shells.

Comparing non-biodegradable plastic with environmentally friendly natural fibre composite on car front bumpers design

Production of plastic is growing, and plastics are used in a variety of products. However, plastics are not biodegradable and do not decompose easily. To overcome the problems in decomposition of plastics, the use of a specific type of natural fibre composite (NFC) material for front-bumper in cars is considered in this investigation. NFCs have the advantages of being environmentally friendly, light weight and high strength. The use of jute fibre is adopted for the design of a car front bumper and compared with the plastic bumper through Finite Element Analysis. The aim is to identify their performances in terms of impact energy, strength and resilience. The results show that when both materials were simulated under the same impact force, jute fibre has a lower equivalent stress with 177.1 MPa compare with 293.18 MPa on plastic material. This finding indicates that jute fibre has greater yield limit and more resilient to fracture. The simulation result also shows that jute fibre has a higher equivalent stress of 65.55 MPa on the front bumper compare with a lower equivalent stress of 39.94 MPa on plastic. This suggests that plastic material will yield soon when an impact force is higher. The total deformation after the same impact force in jute fibre is 2.1 mm, which is significantly less than the deformation in plastic with 11.7 mm. Therefore, this research concludes that jute fibre can potentially replace plastic as a green composite material application to minimise environmental damages.Graphical abstract

Natural Fiber Composite Filaments for Additive Manufacturing: A Comprehensive Review

This research explores the potential and significance of 3D printing natural fiber composite (NFC) materials. The primary objective is to investigate the mechanical, thermal, and environmental properties of NFC filaments, mainly focusing on biodegradable, renewable fibers such as jute, hemp, flax, and kenaf. In addition to studying the properties of NFCs, our research delves into the challenges associated with processing, including moisture absorption and fiber-matrix interfacial bonding. The novelty of this work lies in the convergence of traditional composite materials with the versatility of 3D printing technology. NFC filaments offer unique advantages in terms of sustainability, and we examine their potential contributions to the circular economy. By using eco-friendly NFC materials in 3D printing, we aim to present a viable, environmentally responsible alternative to conventional synthetic composites. The importance of 3D printing NFCs stems from the ways their use can align with sustainability goals. These materials provide the advantages of renewability, reduced carbon impact, and in some cases, biodegradability. Their applications extend to various industries, such as automotive, construction, and packaging, where eco-friendly materials are increasingly sought. Such applications showcase the ways in which NFC-based 3D printing can contribute to a more environmentally responsible and sustainable future. This research explores the mechanical, thermal, and environmental properties of NFC materials, highlighting their unique advantages for 3D printing and the potential to have eco-friendly applications in diverse industries.

A Decade Review of Research Trends Using Waste Materials in the Building and Construction Industry: A Pathway towards a Circular Economy

The construction industry is among the most prominent contributors to global resource consumption, waste production, and greenhouse gas emissions. A pivotal step toward mitigating these sectoral impacts lies in the adoption of a circular production and consumption system. The use of alternative waste materials can mitigate landfill accumulation and the associated detrimental environmental effects. To highlight unconventional materials, this study began with a bibliometric assessment via a bibliography analyzis software called “Bibliometrix” (version 4.1.3). The outputs from the analyzis can assist in identifying research trends, gaps in literature and benchmark research performance. The search engine used for sourcing publications was Scopus, using the main criteria as “Waste materials used in building and construction”. The time-period analysed was from 2013 to 2023. The results included publications obtained in journal articles, book chapters and conference proceedings. The assessment reviewed 6238 documents from 1482 sources. The results revealed an array of waste materials; however, rubber, textiles, and ceramics had a significant reduction in research attention. Rubber waste presents promising opportunities in civil concrete construction methods. The preparatory steps of textile fibres in composite materials are frequently disregarded, resulting in structural issues for the end-product. Obstacles persist in ceramic technology due to the absence of transparency, primarily because industry entities closely safeguard proprietary information. While sustainability research often emphasizes emissions, practical trials commonly revolve around integrating materials into current systems. A more comprehensive approach, contemplating the complete lifecycle of materials, could provide deeper insights into fostering sustainable construction practices. Researchers can use these findings when determining trends, research gaps, and future research directions.

Research of the thermal storage properties of thermally conductive carbon fiber-reinforced paraffin/olefin block copolymer composite phase change materials with thermotropic flexibility

This study focuses on the fabrication and evaluation of paraffin (PA)/olefin block copolymer (OBC)/carbon fiber (CF) composite phase change materials (CPCMs) prepared using the melt impregnation process. The resultant PA/OBC/CF CPCMs exhibit superior thermal stability below 200 °C and maintain excellent shape stability at 60 °C. These characteristics are attributed to the alternating soft and hard segments of OBC, wherein the hard segments prevent liquid leakage from PA. The distinct structure of OBC further lends flexibility and recyclability to the PA/OBC/CF CPCMs. The latent heat of these CPCMs ranges from 169.1 to 197.6 J/g. Notably, the CPCMs variant (PA/OBC/CF-1) with 2 wt% CF addition retains 95 % of its initial latent heat even after 100 thermal cycles, thereby demonstrating superior cycling stability. The thermal conductivity of CPCMs with 10 wt% CF is 1.3 times that of pure PA. This significant improvement in thermal conductivity is attributed to the heat conduction pathways provided by the fibrous CF. These results indicate that the fabricated CPCMs offer substantial promise for utilization in low-temperature waste heat recovery applications.

Ground testing of Al-polyurethane shape memory polymer sail material under pulsed light exposure

This article presents a study on design and testing of space sails using Al-polyurethane Shape memory polymer. The properties of the polymer are simulated and tested in the design phase, and the results are compared with the fabricated sail, which is considered nominal. The efficiency of the polyurethane sail is found to be approximately 86.5%. The controllability of the sail is enhanced using a heating system that uses light rays to heat the polymer at specific control spots. The relative deflection at these spots causes a deviation in solar momentum, resulting in a controlled displacement of the sail. This control system is found to be 42% more efficient than conventional vane-type deflection systems. The paper also presents the fabrication of a ground testing apparatus designed to test the sail specimen in laboratory conditions. The apparatus is capable of producing a vacuum chamber pressure up to −400 mm/Hg and includes a magnetic levitation platform with strong permanent magnets to neglect local gravitational effects. The platform provides support for fixing the solar sail frame made from carbon fiber composite material. The testing apparatus consists of a 1000-W halogen light source with intensity ranges of approximately 200,000 lux. Sail material with a reflective surface is exposed to controlled luminance under vacuum conditions to measure the deflection of the sail. Deflection values are recorded by means of a resistance type strain gauge and strain indicator arrangement. Plotting deflections with time period gives the acceleration of the sail inside the test apparatus. A coolant chamber with a ceramic base is also provided to reduce temperature effects inside the vacuum chamber. In conclusion, this study presents a promising approach for the design and testing of solar sails using shape memory polymer and a ground testing apparatus. The results of this research can contribute to the development of more efficient and versatile solar sail technology for fuel-free aerospace propulsion.

Polyimide aerogel/aramid fiber composite with high mechanical strength and thermal insulation for thermal protective clothing

Polyimide (PI) aerogel, as a new organic aerogel material, has the excellent thermal properties of polyimide and the characteristic of high thermal insulation of aerogels, and has gained increasing attention. In this work, using PI aerogel as the matrix material and aramid fiber as the reinforcement material, controllable flexible PI aerogel/aramid fiber composite insulation materials were successfully prepared by freeze-drying and soft treatment. This study sought to determine how the mass percentage of PI aerogel affected the microstructure, mechanical characteristics, thermal insulation capabilities, and thermal comfort of clothes in PI aerogel/aramid fiber composites. To achieve this, the preparation process of PI aerogel was optimized, and the effects of different mass fractions of PI aerogel on the properties of the composite material were evaluated. The results demonstrated that increasing the mass fraction of PI aerogel led to improvements in the mechanical properties, flexibility, and heat insulation properties of the composite material. Furthermore, the PI aerogel/aramid fiber composite offered enhanced thermal comfort to the wearer in hot and humid environments, indicating that the composite material is particularly suited for thermal insulation applications.

Tribological, mechanical, and metallurgical performance of natural fiber-reinforced composites: A comprehensive review

Composite materials have an ever-increasing demand for their application in numerous applications such as aerospace, automobile, petroleum, etc. These materials vary according to their chemical composition, properties, manufacturing techniques, etc. Natural fiber-reinforced composites are the composites where natural fibers such as plant, animal, and mineral fibers are used as reinforcement material. Reinforcement of these fibers yields composite material with extensive properties such as high strength, durability, reliability, etc. These properties lead them to commercial applications in several areas. Therefore, this paper describes various characteristics of the matrix, reinforcement, and resin used for natural fiber composite materials. Also, multiple parameters that affect the growth of these composites are investigated. The tribological behavior of natural fiber composites is focused mainly on friction, wear, and lubrication. Furthermore, the material's mechanical performance and metallurgical behavior are also given significant importance. These materials’ application in various fields is explored separately, and multiple conclusions are drawn.

Carbon fiber comparison to traditional materials for the automotive industry

As automotive technology continues to advance; the industry is confronted with the ongoing challenge of improving car performance while maintaining safety and structural integrity. This long-standing challenge in the field of automotive technology may soon find a solution through the emergence of carbon fiber composite materials, potentially ushering in a new era of material dominance. Carbon fiber composites possess exceptional strength and extreme stiffness compared to metals, yet they exhibit a much lower density 80% less than steel. This unique combination of properties makes carbon fiber a possible alternative for automobile materials. Moreover, carbon fiber is a more sustainable material compared to traditional metals, offering environmental benefits. It also enables more efficient manufacturing techniques, contributing to reduced energy consumption and waste production. The present study investigates the feasibility of utilizing carbon fiber as the primary material for future automobiles, exploring the intricate aspects of its manufacturing process and examining the wide range of applications associated with this new material. By investigating carbon fiber's potential, the automotive industry could unlock many new opportunities for improved vehicle performance, fuel efficiency, and sustainability.

Strength and damage analysis of composite tube with metal lining

Based on the analysis of the structure and force characteristics of the composite tube, the feasibility of the finite element model is verified by conducting a quasi-static hydrostatic test on the new composite body tube combining carbon fiber composite material and metal lining, and comparing the ABAQUS finite element simulation to simulate the gradual damage and failure of the composite cylinder under hydraulic load. Based on the verified finite element model, the influence of single-angle spiral padding and multi-angle gradient spiral alternating padding on the pressure-bearing performance of composite tube is deeply explored, and the numerical analysis results show that the multi-angle gradient spiral lay-up method can make the composite tube show better performance. Based on the premise of this ply method, the univariate method was used to study the influence of carbon fiber grade on the pressure bearing performance of composite tube.

Numerical simulation of the melting and solidification processes of stearic acid/carbon fiber composite phase change material for solar water heating applications

Phase Change Materials (PCMs) are one of the most promising materials for storing thermal energy and supplying stored energy for Domestic Hot Water (DHW) applications. This paper presents a detailed numerical analysis to describe transient heat transfer in a phase-change composite thermal energy-storage system. The composite was composed of 92.5 % stearic acid, 7.5 % carbon fiber, and a heat transfer fluid (ethylene cellulose). Numerics were implemented using ‘The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics’. The results were validated using experimental data and demonstrated acceptable agreement and an accurate representation of this specific transient heat transfer problem. The difference between the simulation and experimental results was so small that we considered the simulation results reliable. When the phase change heat storage process is about 800 s, the heat is transferred to the entire phase change heat storage tank, and when the phase change heat storage process is about 10800s, the temperature of all composite phase change materials reaches the phase change temperature. When the phase change heat storage process is about 8 h, the temperature of the composite phase change material in the whole phase change heat storage tank reaches 90 ℃. The temperature tends to be stable after the phase transition heat release process for about 500 s, and there is no large fluctuation in temperature with the passage of time. When the phase change heat release process reaches 7200 s, the cold-water inlet temperature is 15 ℃, 20 ℃ and 25 ℃, and the outlet temperature is 25.8 ℃, 30.8 ℃ and 35.7 ℃, respectively, indicating that the application of composite phase change materials in phase change heat storage water tank has a good effect.

Generative AI and image based numerical mechanics in wind blade adhesive composites

Numerical modelling of adhesive composites in wind energy is complicated in part due to material heterogeneity. Microstructural CT scan fibre composite patterns or representative elements, which play a major role in defining the mechanical behaviour of these adhesive structures, are both difficult to characterize as well as hard to numerically simulate. With advances in deep learning based generative AI, new ways of predicting the mechanical behaviour of heterogeneous materials is now possible. Here we put forward a data driven method to relate input composite adhesive microstructures with field data using deep learning and generative AI based methods. The prediction of mechanical stress or strain fields or other similar patterns and combining them as a function of boundary conditions, fibre composite microstructure and material models is achieved and the models are trained such that they closely approximate computationally expensive simulations based on numerical FE techniques and would have the ability to generalize. We also create a dataset of wind energy adhesives with their numerical mechanics based FE simulations subject to different boundary conditions and material models for further deep learning based composite studies.