Advanced Composites Research Articles

Toray Advanced Composites announces new strengthened polyamide thermoplastic material for high-performance applications

On March 5, 2024, Toray Advanced Composites introduced the new product Toray Cetex® TC915 PA+™ into its extensive portfolio. Toray Cetex® TC915 PA+™ reportedly is excellent for sporting goods, high-performance industrial applications, automotive structure, energy (oil/gas & hydrogen), Urban Air Mobility (UAM), and Unmanned Aerial Systems (UAS) applications.

Preparation and characterisation of graphitic biochar materials derived from rose oil industry waste via different pyrolysis durations and ball milling for advanced composites

The valorisation of waste from rose-based industrial products produces value-added substances and paves the way for advanced composites. The rose waste generated from the essential oil industry of the Taif rose (Rosa damascena trigintipetala Dieck) is significant, and its management or disposal is a source of concern. In this study, it was valorised to produce a value-added nanomaterial. The synthesis of biochar nanoparticles via high-energy ball milling has gained tremendous research interest in recent times because of its low cost and eco-friendliness. Ball milling is a solvent-free technology with strong potential for waste volatilisation and eco-sustainability through the production of engineered biochar nanoparticles. Different biochar samples were produced and characterised to harness the synergistic combination of biochar production and ball milling. They were prepared at a constant pyrolysis temperature of 300 °C by varying the pyrolysis times for 2 h, 5 h, and 10 h. The characterisation results showed that pyrolysis confirms a high content of carbon, minerals, graphitic structure, novel morphology and chemical characteristics attached to the biochar surface controlled by different pyrolysis durations. These properties were further enhanced by ball milling for 10 h. The results showed that ball milling enhanced the porosity, surface area, surface functional groups, visible light absorption, crystallinity, and carbon content, and these were accompanied by a reduction in the particle size and mineral impurities. The engineered biochar can be an important tool, with promising potential in novel composites for water purification and energy harvesting.

Zone of Preferential Heating for Minor Ions in the Solar Wind

The properties of minor ions in the solar wind are important indicators of the state of the solar corona and the heating processes it undergoes as it expands. Evidence of preferential heating of minor ions has been observed in the solar wind, and is believed to be active up to a certain radial boundary, beyond which thermalization due to Coulomb collisions predominates. Building on previous works that calculated the location of this boundary for alpha particles, this work calculates the outer radial boundary of the zone of preferential heating for selected heavy ions in the solar wind. This analysis uses ion data from the Solar Wind Ion Composition Spectrometer and proton data from the Solar Wind Electron, Proton, and Alpha Monitor aboard the Advance Composition Explorer spanning the years from 1998 through to 2011. Observations of proton and ion temperatures, velocities, and densities, and fixed parameters derived from temperature, density, and velocity scaling laws are used in a model function to predict the radial boundary and excess temperature at the boundary via reduction of the χ 2/degrees of freedom statistic. In this study, the values of the radial boundary of the preferential heating zone were quite high when compared to what was previously found for alpha particles, but a clear scaling relationship between excess temperature and ion properties was observed.

Towards Understanding of the Plastic Zone Thermal Residual Stresses in Functionally Graded Materials

Abstract: Functionally graded materials (FGM’s) are advanced composites consisting of two or more materials whose composition and structure changes gradually over the volume, leading to gradual change in its property. Typically one component is a ceramic, while the other is metal or metal alloy. In common embodiments, the composition can change gradually from all ceramic on one side to all metal on the other side, the ceramic contributing high resistance to temperature with the metal contributing high ductility. It’s a way to incorporate favorable properties of two materials into different locations of a single structure. In ideal cases the composition changes gradually but for manufacturing reasons, the changes occurs in homogeneous layers. The boundaries between the layers cause thermal residual stresses to arise, especially during material processing and in cases of cyclic loading. These thermal residual stresses are a result of differences in the thermal expansion coefficient of the varying compositions of materials. Thermal residual stresses may lead to cracking and ultimate failure of FGM’s. This study investigates the formation of thermal residual stresses for a Nickel-Alumina Ni-Al₂O₃ FGM. The Ni-Al₂O₃ system is chosen because it is one of the most common systems used in practice. This work explores the formation, impact and minimization of thermal residual stresses for a number of practical conditions that may arise during processing. All relevant properties are calculated using the rule of mixture equations.

Minimizing the Formation of Thermal Residual Stresses of the Elastic Zone in Functionally Graded Materials

Abstract: Functionally graded materials (FGM’s) are advanced composites consisting of two or more materials whose composition and structure changes gradually over the volume, leading to gradual change in its property. Typically one component is a ceramic, while the other is metal or metal alloy. In common embodiments, the composition can change gradually from all ceramic on one side to all metal on the other side, the ceramic contributing high resistance to temperature with the metal contributing high ductility. It’s a way to incorporate favorable properties of two materials into different locations of a single structure. In ideal cases the composition changes gradually but for manufacturing reasons, the changes occurs in homogeneous layers. The boundaries between the layers cause thermal residual stresses to arise, especially during material processing and in cases of cyclic loading. These thermal residual stresses are a result of differences in the thermal expansion coefficient of the varying compositions of materials. Thermal residual stresses may lead to cracking and ultimate failure of FGM’s. This study investigates the formation of thermal residual stresses for a Nickel-Alumina Ni-Al₂O₃ FGM. The Ni-Al₂O₃ system is chosen because it is one of the most common systems used in practice. This work explores the formation, impact and minimization of thermal residual stresses for a number of practical conditions that may arise during processing. All relevant properties are calculated using the rule of mixture equations. Abaqus, a non-linear FEA solver, is used for all the simulation work. In addition, the study highlights the need for examining elasto-plastic analysis to illuminate the process of crack development which is our future research goal.

Finite Element Modeling of the Plastic Zone Thermal Residual Stresses in Functionally Graded Materials

Abstract: Functionally graded materials (FGM’s) are advanced composites consisting of two or more materials whose composition and structure changes gradually over the volume, leading to gradual change in its property. Typically one component is a ceramic, while the other is metal or metal alloy. In common embodiments, the composition can change gradually from all ceramic on one side to all metal on the other side, the ceramic contributing high resistance to temperature with the metal contributing high ductility. It’s a way to incorporate favorable properties of two materials into different locations of a single structure. In ideal cases the composition changes gradually but for manufacturing reasons, the changes occurs in homogeneous layers. The boundaries between the layers cause thermal residual stresses to arise, especially during material processing and in cases of cyclic loading. These thermal residual stresses are a result of differences in the thermal expansion coefficient of the varying compositions of materials. Thermal residual stresses may lead to cracking and ultimate failure of FGM’s. This study investigates the formation of thermal residual stresses for a Nickel-Alumina Ni-Al₂O₃ FGM. The Ni-Al₂O₃ system is chosen because it is one of the most common systems used in practice. This work explores the formation, impact and minimization of thermal residual stresses for a number of practical conditions that may arise during processing. All relevant properties are calculated using the rule of mixture equations. Abaqus, a non-linear FEA solver, is used for all the simulation work. In addition, the study includes an elasto-plastic analysis to illuminate the process of crack development.

Dynamic Viscoelastic Properties of Kenaf Fiber Reinforced Shape Memory Polymer Composites

This paper comprehensively investigates the dynamic viscoelastic behavior of shape memory polymer composites (SMPCs) reinforced with different weight percentages of kenaf fiber (KF) ranging from 0%, 5%, 10%, 15%, 20%, 30% and 40%. The dynamic mechanical behavior of these composites was characterized using dynamic mechanical analysis (DMA) over a range of temperatures. The objective was to determine the optimal fiber content of KF as reinforcement in SMPCs, specifically on viscoelastic response, storage modulus, loss modulus, damping and glass transition behaviour. The results revealed a clear correlation between the KF contents and the dynamic mechanical properties of SMPCs. The storage modulus significantly improves at higher KF content, particularly at elevated temperatures. Additionally, a quantitative assessment of coefficient C demonstrates strong interfacial bonding between fibers and the matrix in samples 30KF and 40KF. These samples also exhibit higher loss modulus and lower tan delta values, providing evidence for the efficacy of KF in enhancing composite properties. Moreover, higher KF contents induce a shift in the glass transition temperature, signifying enhanced in fiber-matrix interaction and thermal stability. The Cole-cole further demonstrates that at higher KF content, the sample surpasses Neat SMPU, presenting compelling evidence of improved matrix-fiber bonding. Statistical analysis through one-way analysis of variance (ANOVA) substantiates the statistical significance of the dynamic mechanical properties across the different weight percentages of KF-SMPCs. Based on these findings, 30KF is the optimal fiber content, balancing mechanical enhancement and feasible fabrication. This decision is grounded in challenges encountered at 40KF, where ensuring composite homogeneity becomes complex. This study contributes to the growing body of knowledge on utilization of natural fibers in development of advanced polymer composites while maintaining eco-sustainability.

A Comprehensive Comparison of Various Galactic Cosmic-Ray Models to the State-of-the-art Particle and Radiation Measurements

Galactic cosmic rays (GCRs) are the slowly varying background energetic particles that originate outside the solar system, are modulated by the heliospheric magnetic field, and pose ongoing radiation hazards to deep space exploration missions. To assess the potential radiation risk, various models have been developed to predict the GCR flux near Earth based on propagation theories and/or empirical functions. It is essential to benchmark these models by validating against the state-of-the-art measurements. In this work, a comprehensive model–observation comparison of the energy-dependent particle flux has been performed, by combining five typical GCR models and observational data from the Cosmic Ray Isotope Spectrometer on board the Advanced Composition Explorer spacecraft at relatively lower energies and data from the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics and Alpha Magnetic Spectrometer at higher energies. The analysis shows that, out of the five models investigated in this study, the optimal model, characterized by minimal relative difference or reduced chi-square divergence from measurements, depends on the particle type, energy range, and epoch of interest. Furthermore, a silicon slab is applied to compute the absorbed dose rate using conversion factors applied to GCR model outputs, and the results are compared to measurements from the Cosmic Ray Telescope for the Effects of Radiation. The comparisons in this paper have implications for the strengths and limitations of individual GCR models, advance our comprehension of the underlying GCR transport mechanisms, and also have strong application aspects for mitigating space radiation risks.

Advances and Challenges in Cerebral Organoids Research

Cerebral organoids are three‐dimensional (3D) aggregates with a more advanced composition, maturation, and architecture. It has emerged as a novel and sophisticated model system for studying neurodevelopment and neurological disorders, in comparison to conventional two‐dimensional (2D) cell cultures. However, due to the extraordinarily complex nature of brain development, current cerebral organoids are not as functional and mature as brains. The development of cerebral organoids requires a culture system with sufficient developmental patterning factors, essential cell components, and vasculature. In this review, the critical factors and events that contribute to the development of cerebral organoids are focused on. The advanced design, fabrication techniques, and technologies are also discussed to enhance the application potential of cerebral organoid technology.

Bioepoxy based advanced lightweight hybrid composites from hemp fibers: Towards greener production

Over the past few decades, the widespread use of composite materials has become prominent, particularly following the industrial revolution. In response to environmental concerns, natural fiber polymer composites have found extensive applications, notably in the automotive industry and various versatile applications. However, pure natural fiber polymer composites face challenges in matching the performance of synthetic fiber-reinforced polymer composites. To address this issue, natural fibers are hybridized with synthetic fibers to enhance the performance characteristics. In this study, hemp fibers were hybridized with Innegra fibers through a stacking sequence and subjected to weathering. Both the weathered and unweathered composites underwent mechanical, thermal, and viscoelastic analysis to assess their performance under harsh environmental conditions. The mechanical analysis revealed that the tensile strength of the composite with Innegra as the skin layer was 76.56 MPa, reducing to 67.73 MPa after the weathering process. The flexural strength showed values of 111.01 MPa and 101.61 MPa before and after the weathering process, respectively. Thermomechanical analysis indicated that pure hemp composites exhibited lower thermal expansion at 1.45%, with the composite featuring hemp fibers in the outer layer performing better at 2.34% compared to hybrid composites. Additionally, SEM images demonstrated good interfacial adhesion between fibers and the matrix. Overall, the results suggest that the developed composites have the potential for use in lightweight semi structural applications.

Evaluation of manufacturing methods for pultruded rod-based hierarchical composite structural members with minimal porosity

Bio-inspired, hierarchical structures following the example of natural composites such as bone, wood or bamboo promise a new approach to advanced composites. This work focuses on hierarchical composites based around pultruded carbon fibre-epoxy rods, rather than layered plies of material. A structural member, or strut, of circular cross-section, consisting of cured pultruded rods and epoxy resin, demonstrates this hierarchical concept. This paper focuses on manufacturing of struts by vacuum infusion and by pressurised resin transfer moulding, with the aim of minimising porosity while retaining the desired cross-section. Rod alignment and packing are also considered. Vacuum infusion is carried out with stiff and flexible tooling, and pressurised resin transfer moulding using rigid cylindrical copper tools with and without a flexible liner. Porosity is measured via X-ray computed tomography. The results indicate a way forward for manufacturing low porosity hierarchical composites based on pultruded rods, either via vacuum infusion with a flexible tool, requiring machining to reach a circular cross-section, or pressurised resin transfer moulding using a combination of rigid tool and flexible liner at 3 x 105 Pa or higher, where porosity is below the limit of detection in a Nikon XTH-320 CT scanner.

Multispacecraft Energetic Particle Enhancements Associated with a Single Corotating Interaction Region

The radial evolution of particles accelerated at corotating interaction regions (CIRs) is not fully understood, particularly the distance range over which this particle acceleration occurs and how the energy spectra are modulated by transport through the inner heliosphere. Here, we present observations of energetic proton enhancements associated with a CIR observed by Parker Solar Probe on 2021 April 25 during the inbound leg of its orbit near ∼46 R s (∼0.21 au). The CIR is identified at additional spacecraft (Solar Terrestrial Relations Observatory, STEREO-A; Solar Orbiter, SolO; and Advanced Composition Explorer, ACE) using a corotation time delay estimation, and energetic proton spectra from each spacecraft are compared. We find that (1) energetic protons are observed near 46 R s streaming sunward ahead of the CIR; (2) the CIR persists for at least one solar rotation and the corresponding energetic proton enhancements are observed at STEREO-A, SolO, and ACE; and (3) the proton energy spectrum is steeper near the Sun and hardens near 1 au. This observation presents the closest in situ energetic particle observation of a CIR to the Sun ever recorded. Results presented here suggest that particles can be accelerated by CIR structures within 1 au and these particles can penetrate very deep into the inner heliosphere.

Harmonic Excitation Response of Standard Ultrasonic Horn Designs for Machining Nomex Honeycomb Core Composite

Ultrasonic horn plays a vital role in achieving vibration amplitude at tool end (VATE) by enhancing output displacement of piezoelectric ultrasonic transducer suitable for efficient machining of advanced composites. Higher vibration amplitude enhances ultrasonic machining quality, surface integrity and dimensional accuracy of Nomex honeycomb composite (NHC) while reducing cutting forces. Furthermore, low stress concentrations allow ultrasonic tool to have more safety factor and longevity. Ultrasonic horn is designed to enhance displacement amplitude of piezoelectric ultrasonic transducer and get optimum VATE while keeping stresses in acceptable limits to avoid failure at very high operating frequency of ultrasonic machining system. In this research, variety of standard ultrasonic horns (SUH) were designed with same length and end diameters; and were tested under similar operating conditions, using finite element method. The ultrasonic actuation of the horn exploits the first axial mode of horn vibration. Harmonic response analysis was carried out to determine axial modal frequencies (AMF), VATE, stresses, and factor of safety for performance evaluation. VATE attained by step horn was found to be greatest among all other SUHs for frequency ratio greater than one, but may be prone to early failure due to high stress concentrations. VATE achieved by third order Bezier, Gaussian, exponential, catenoidal, conical and second order Bezier horns were found less than that of step horn by 11.7 %, 16.6 %, 16.7 %, 17 %, 16.73 % and 18 % respectively. However, 44.2 %, 43.43 %, 42.5 %, 43.5 %, 42.8 % and 37.67 % reduction of stresses was achieved by Gaussian, exponential, catenoidal, conical, second and third order Bezier horns respectively. Outcomes of present work would be beneficial for designers, researchers, scientists, and manufacturers of ultrasonic machine tool to select appropriate SUH designs according to requirements.

Recent progress in carbide‐based composite materials fabricated by laser additive manufacturing processes

AbstractFabricating and introducing new materials with new features is one of the most important goals for many scientific groups. Today, additive manufacturing (AM) is known as one of the new production methods, which can create an excellent opportunity for achieving this goal. As one of the ongoing production processes, the laser AM (LAM) methods have the proper capacity for producing new advanced materials like carbide, nitride, and boride‐based materials. Hence, this work aims to review carbide‐based materials produced by LAM techniques with the composite viewpoint. These materials can act as a matrix, reinforcement, or tertiary component in advanced composites. With this viewpoint, these composite materials were introduced in eight separate sections, which are tungsten carbide, titanium carbide, silicon carbide, niobium carbide, chrome carbide, vanadium carbide, and boron carbide, as well as high entropy alloy composites.

Regulating synergistic micro-nano pore structure of CNT sponge to control EMI shielding performance

The aggregation in high-content carbon nanotube reinforced silica carbide composites (CNT/SiC) imposed constraints for further large-scale industrial applications. This study established a synergistic micro-nano pore structure by assembling CNT bundles to fabricate the CNT sponge preform, and then the SiC matrix was in-situ deposited by chemical vapor infiltration method, which facilitates composites with high density and exceptional properties. The pore size distribution and pore area can be regulated by simply adjusting the compression ratios (CRs) of the as-assembled CNT sponge. Samples with CR of 50 % exhibited noteworthy densification, significantly reduced porosity, and a remarkable 163.54 % extra increase in compression strength compared to uncompressed ones. Additionally, the CNT/SiC composites displayed excellent oxidation resistance and demonstrated improved electromagnetic interference (EMI) shielding performance, which exhibited a substantial increase with higher CRs. These findings underscore the significance of employing appropriate multi-level porosity in CNT preforms to fabricate advanced ceramic matrix composites with superior EMI shielding capabilities.

Impact loading of glued laminated timber beams without finger-joints

Progressive collapse can be triggered by impact loading from vehicles or other objects and propagated by impact loading from falling debris. Therefore, the correct modeling of impact loading is necessary to assess the resistance of a structure against progressive collapse. As the number of timber buildings increases, the importance of adequate considerations of impact loading is growing. Previous research on impact loading of wood or timber was carried out on small clearwood specimens or on single boards. However, modern timber buildings use advanced wood-based composites, such as glued laminated timber and laminated veneer lumber. The characteristics of these materials are widely different from clearwood and single boards. In this paper, energy-based equations are derived for the peak impact force and the dynamic strength increase factor. These are quantified by pendulum impact hammer tests on 95 full-size glued laminated timber beams. The results are applied in a calculation example to demonstrate their potential use in practice.

Structurally engineered 3D porous graphene based phase change composite with highly efficient multi-energy conversion and versatile applications

Micro-nano encapsulation strategy combining three-dimensional (3D) porous carriers and phase change materials (PCMs) has been widely investigated due to its structure stability, high efficiency, and designability. However, the current 3D scaffolds suffering from structure regularity are hard to meet the urgent requirements of high energy conversion efficiency and versatile applications. Herein, a 3D porous graphene scaffold (2LrGO@LIG), which is fabricated from polybenzoxazine/graphene oxide (GO) composite using laser irradiation that structurally engineers a gully-shaped surface and a 3D overlapped graphene networks, was employed for PCMs encapsulation. The addition of GO is proved to enhance the quality of produced laser induced graphene (LIG), which could also be reduced into laser-reduced graphene oxide (LrGO) and connect the adjacent LIGs as thermal bridges. As a consequence, the obtained phase change composite (2LrGO@LIG/MA) showed photo-thermal and electro-thermal conversion efficiency of 94.1 % and 99.1 %, respectively. In addition, benefiting from the surface hydrophobicity (135°), high energy storage density (167.7 J/g) and electrical conductivity (307.9 S/m), 2LrGO@LIG/MA also demonstrated great potential in smart building materials and wearable electronic devices. This study provides a facile method for designing advanced PCM composites with multi-energy conversion capacity and application versatility.

Digital twin and cross-scale mechanical interaction for fabric rubber composites considering model uncertainties

Digital twin ushers in growth as one cutting-edge technology that enables high-precision, informative and real-time interaction of advanced composites, influencing the paradigm of composite analysis and design in aerospace, automotive, intelligent electronics and other fields. The online and fine evolution of digital twins at scale face challenges due to creating scalable predictions, updates, and controls with coupled information in workflows. In this work, an interactive digital twin methodology for complex composite structures (CCSDT) based on machine learning is introduced. To demonstrate the framework's feasibility and applicability, a hybrid architecture comprising hierarchical deep neural networks (H-DNNs), statistical inference and cross-scale physical constraints is proposed considering the fabric rubber composites (FRC) in aerospace field. The framework predicts 3D displacement and stress fields directly from sensing features and can incorporate dynamic updating and evaluation of computational models into data assimilation. Real-time prediction and uncertainty quantification are verified through synthetic and experimental data, and the capability of CCSDT in perception and decision is demonstrated by a case of cruise state monitoring. The comparison between the measured strain field and the post-processing predicted strain field shows the extensibility of the direct prediction results. These results provide guidance for the development of composite digital twins, stimulating the potential for cost-effective and efficient digital twin services.

Predicting the crack repair rate of self-healing concrete using soft-computing tools

To tackle the challenges of cracking and insufficient durability in traditional concrete, researchers are exploring self-healing concrete (SHC) as a potential alternative material. Nevertheless, doing laboratory studies can incur significant expenses and consume considerable time. Therefore, utilizing machine learning (ML) algorithms can contribute to advancing improved predictions for self-healing concrete. This study aimed to create ML models, specifically adaptive boosting (AB), artificial neural network (ANN), and gradient boosting (GB), to forecast and evaluate the repair rate of the cracked region in SHC that incorporates fibers and bacteria in their compositions. To further evaluate the importance of inputs, RReliefF analysis was performed. The findings indicated that the AB algorithm outperformed GB and ANN algorithms by achieving a coefficient of determination (R2) value of 0.987, a mean absolute error (MAE) value of 0.001 mm, and a root mean square error (RMSE) value of 0.026 mm. The GB approach yielded an R2 value of 0.962, an MAE value of 0.035 mm, and an RMSE value of 0.044 mm. Similarly, the ANN approach yielded an R2 value of 0.943, an MAE value of 0.040 mm, and an RMSE value of 0.054 mm. These results demonstrate that all AB, GB, and ANN algorithms outperformed in terms of prediction accuracy and model fit. Hence, the application of these models can be employed to construct and verify advanced SHC compositions that rely on polymeric fibers and bacteria, aiming to achieve superior performance. However, comparing the outcomes of developed models revealed that the AB model accuracy is higher than the GB and ANN models for predicting the area repair rate of cracks.

Phase, Microstructure and Tensile Strength of Ultrasonically Stir Casted Al6061-TiC-Graphite Hybrid Metal Matrix Composites

This study investigates the microstructural and mechanical behavior of Al6061-TiC-Graphite hybrid metal matrix composites fabricated by the ultrasonically stir casting process. The effects of TiC and graphite on the phase, microstructure, hardness, and tensile strength of the composites are evaluated. Scanning electron microscopy, Energy dispersive spectroscopy, and X-ray diffraction analysis techniques were used to investigate the microstructure and phase composition of the composites. The results show that the addition of TiC and graphite improves the microstructure and mechanical properties of the composites. The maximum hardness and tensile strength were obtained for the composite with 2[Formula: see text]wt.% TiC and 1[Formula: see text]wt.% graphite. The study provides insight into the development of advanced metal matrix composites with improved mechanical properties for potential use in various industrial applications.