Composite Parts Research Articles

Enhancing structural performance of recycled fiber-reinforced thermoplastic composite part through incorporating composite laminate precuts

Enhancing structural performance of recycled fiber-reinforced thermoplastic composite part through incorporating composite laminate precuts

Processability and properties of cubic‐BaTiO3/poly(vinylidene fluoride) composites for additive manufacturing: From powder compounding to 3D‐printed parts

AbstractPoly(vinylidene fluoride) (PVDF) is a piezoelectric and thermoplastic material with great potential for additive manufacturing (AM) applications. Using barium titanate (BaTiO3) as filler, PVDF‐based composite materials were developed, characterized, and processed by AM material extrusion (MEX). The morphological features and phase transformations occurring throughout the processing of BaTiO3‐filled PVDF, from the compounding to the printed part, were analyzed. The morphology of the powder feedstock after dispersion in a high‐energy ball mill changed from spheroidal to laminar and β‐phase formation was favored. Microhardness gradually increased with the BaTiO3 content, obtaining an enhancement of ~60% for a content of 25 vol%, and supported the good dispersion of the filler. A ~48% increase of the dielectric permittivity was also achieved. After extrusion, filaments with a filler content of 15 vol% showed a more stable diameter, as well as higher crystallinity and surface roughness, compared with those with lower BaTiO3 contents. Material extrusion of filament and direct printing of pellets based on MEX were successfully used to obtain AM parts. Composite parts showed enhanced surface roughness, hydrophilicity, and flexural modulus (up to ~33% for the 7 vol% composite compared with the PVDF), thus leading to superior mechanical characteristics and potential biomedical applications.Highlights Dry high‐energy ball milling was a suitable greener dispersion approach. MEX processes were successfully used to obtain 3D‐printed parts. The use of direct printing of pellets/powder improved the 3D printability. The surface roughness and hydrophilicity increased with the filler content. The permittivity and elastic modulus increased with the filler content.

Field sensing of temperature and degree of cure for composites manufacture using parameterized physical‐informed neural networks and sparse FBG sensors

AbstractMonitoring the curing process of polymer composite parts stands imperative for improving the quality and efficiency of manufacturing processes. This paper proposes a field sensing framework that fuses parameterized physics‐informed neural networks (PPINN) and sparse fiber Bragg grating sensors to provide real‐time estimates of temperatures and degree of cure field in composite parts. Moreover, a novel separation network is developed for constructing the PPINN predictor, which integrates the coupled partial differential equation of the thermochemical curing process, achieving data‐free training and real‐time performance. In the simulation experiment, temperature accuracy reached 99.7%, while in laboratory experiments, the accuracy reached 96.1%. Both simulation and experiment demonstrated the successful field sensing of the temperature and degree of cure field in a negligible time with noise resistance ability.Highlights Proposed framework integrates PPINN and sparse FBG sensors for field sensing. PPINN solves thermo‐chemical equations without simulation data required. Simulation accuracy reaches 99.7%, and experimental accuracy reaches 96.1%. The framework shows strong resistance to noise interference in experiments.

A Pressure-Bearing Microwave Transmission Line for Rapid Energy-Efficient Manufacturing Systems of High-End Composite Parts

Currently, a 2-port microwave transmission line with a glass window is usually used to transmit microwave energy to a pressure vessel while sealing the high-pressure gas. In this situation, the damage of the brittle glass window will inevitably result in disastrous accidents. In this paper, the idea of a “2+4”-port microwave transmission line is first proposed to solve this problem. A 4-port waveguide bridge structure is connected to the input port of a traditional 2-port structure, which can release the high-pressure gas safely when the glass window of the 2-port microwave transmitting structure fails. To test this idea, a “2+4”-port microwave transmission line at 2.45 GHz was designed and fabricated. The effectiveness of the whole system in microwave transmission was validated by both simulations and experiments. A high microwave transmittance of more than 97% in the simulation and 91% in the experiment was achieved. The long-time transmission of 15-kW microwave energy, 5 times higher than the previous work, was realized. Moreover, the effectiveness of the transmission line in releasing high-pressure gas (0.6 MPa) was validated by a series of fluid-structure interaction simulations. This research proposes a new transmission structure for transmitting microwave into a pressurized environment safely and efficiently, which can be promoted to a series of applications including vacuum electron devices, microwave ovens, and so on.

Potential Effect of Defatted Mealworm Hydrolysate on Muscle Protein Synthesis in C2C12 Cells and Rats

(1) Background: the objective of this study was to examine the impact of defatted mealworm hydrolysate (DMH), formulated through protein hydrolysis, on muscle protein synthesis in C2C12 cells and rats; (2) Methods: C2C12 cells were treated with dexamethasone and DMH, and cell viability was quantified using the MTT assay. Twenty-four Sprague–Dawley rats were divided into three groups (control, DEX, and DEX + DMH) and treated for 8 weeks. The DEX and DEX + DMH groups were administered intraperitoneal injections of DEX at a concentration of 2.25 mg/kg over a 3-d period. The control and DEX groups were fed a control diet, whereas the DMH group had part of the protein composition of the control diet replaced with 3.5% of DMH. The impact of DMH on muscle protein synthesis was evaluated through the measurement of grip strength, gastrocnemius and tibialis anterior muscle weights, and the investigation of muscle protein synthesis and degradation factor mRNA expression utilising the real-time PCR method; (3) Results: in vitro experiments demonstrated that treatment with DMH at concentrations greater than 5 mg/mL markedly alleviated DEX-induced injury in C2C12 cells. In vivo experiments demonstrated that the mRNA expression levels of myogenin and myoblast determination proteins, which promote muscle protein synthesis, were significantly increased. Furthermore, rats fed DMH exhibited significantly enhanced grip strength and tibialis anterior weight; (4) Conclusions: these findings indicate that DMH may serve as a functional material capable of promoting muscle protein synthesis and that the utilization of proteolytic enzymes is advantageous for the effective utilization of mealworms.

Thermocycling test of a titanium-carbon fiber adhesive joint produced using laser texturing technology

In spacecraft load-bearing structures, adhesive bonding of titanium alloy and composite material parts is often used. To increase the strength of the adhesive bond of the titanium-carbon fiber reinforced plastic pair, preliminary treatment of the bonded surfaces is necessary. In this paper, it is proposed to use laser texturing to process the metal surface. The main objective of the study is to experimentally determine the strength characteristics of the adhesive bond of carbon fiber reinforced plastic and titanium alloy with different modes of laser processing of the metal surface and to determine the effect of thermal cycling on the samples of the adhesive bond. The surface of the OT-4 titanium alloy was laser processed in different modes, after which the samples were glued with VK-9 and LOCTITE® EA 9394 AERO glue. The glued samples were subjected to thermal cycling in a vacuum chamber in the temperature range from –150 to +150 °C. Shear testing of adhesive bond samples showed that laser texturing increases bond strength by an average of 60% for LOCTITE® EA 9394 AERO adhesive and by 142% for VK-9 adhesive. Samples with laser texturing have a cohesive nature of failure on carbon fiber. During thermal cycling, most samples show a slight decrease in adhesive bond strength by an average of 6...8%. The results show that the use of laser processing to prepare titanium alloy before bonding with composite material is a promising method for increasing the strength of adhesive bonds for spacecraft components.

PMA Polymeric materials and their applications

Materials obtained from nature are divided into two groups: natural and artificial. Materials fall into four main categories: metals, ceramics, polymers, and composites. Glass is a solid material that is transparent, usually rigid, fragile, and has an inorganic amorphous structure that allows the preservation of liquids. Ceramics, on the other hand, are solid materials containing metal and non-metal inorganic compounds with ionic or covalent bonds. Nontechnical ceramics fall into three general groups: cement and concrete, fired clay, minerals, and stone. Fibers and particles are utilized as strengthening constituents in different types of composite materials. Hybrids can be used as different types of composite materials and thermal insulation parts. Hybrid materials are divided into four groups: composites, foams, honeycombs, and natural materials. Composites and foams can be made from metallic, ceramic, or polymer-based matrices. Metals and their alloys are materials connected by metallic bonds. Metals are divided into two groups: ferrous and non-ferrous. A polymer is a substance comprised of enormous molecules. Polymers have larger molecular masses than small molecule compounds. Polymers are materials connected by covalent bonds and dominant van der Waals bonds. Polymeric materials are divided into two groups: elastomers and plastics. Plastics (polymers) are divided into two main parts: thermoplastics and thermosets. Thermoplastics can be reused when heated due to their weak bonds, meaning they are suitable for recycling. A thermoset is a thermosetting polymer and is a material attained by permanently hardening the resin. Industrial usage areas of polymers include textiles, electronic goods, the automotive industry, healthcare, building materials, and food. In this study, polymeric materials were defined, then classified and their usage areas were criticized.

Process Optimization Using Cuckoo Search Algorithm for the Manufacturing of Resin Transfer Moulded Composite Parts

An in-house coded cuckoo search (CS) optimization algorithm integrated with a finite element simulation model was developed for resin transfer moulding (RTM) process optimization. At first, the mould filling and curing phases, the vital stages of the RTM process were modelled in the COMSOL multi-physics simulator for RTM6 resin – carbon fibre reinforced composite part. Then, the model was imported to the CS optimization algorithm scripted in MATLAB using the COMSOL live link for MATLAB. The CS algorithm was developed for the minimization of dry spot content by finding the optimal positions of gates and vents during the mould-filling stage and the minimization of the thermal gradient by finding the optimal mould temperature during the curing stage. From the optimization results, there was a decrease in dry spot content and thermal gradient with an increase in generations. With the generations, converged-stable-optimal solutions were obtained. A dry spot content of 3% for one gate and one vent and 0.56% for two gates and one vent was obtained for two-dimensional and three-dimensional composite plates, respectively. From the curing phase optimization results, a minimum thermal gradient of 0.86 K with 98.1% degree of cure was obtained for the optimal mould temperature of 433 K. The developed CS algorithm predicted the better-automated mould-fill and cure phase optimal solutions for the studied composite part.

Phase Field Modelling of Failure in Thermoset Composites Under Cure-Induced Residual Stress

This study examines the residual stress induced by manufacturing and its effect on failure in thermosetting unidirectional composites under quasi-static loading, using Finite Element-based computational models. During the curing process, the composite material develops residual stress fields due to various phenomena. These stress fields are predicted using a constitutive viscoelastic model and subsequently initialized within a damage-driven Phase Field model. Structural tensors are used to modify the stress-based failure criteria to account for inherent transverse isotropy. This influence is incorporated into the crack phase field evolution equation, enabling a modular framework that retains all residual stress information through a heat-transfer analogy. The proposed coupled computational model is validated through a representative numerical case study involving L-shaped composite parts. The findings reveal that cure-induced residual stresses, in conjunction with discontinuities, play a critical role in matrix cracking and significantly affect the structural load-carrying capacity. The proposed coupled numerical approach provides an initial estimation of the influence of manufacturing defects and streamlines the optimization of cure profiles to enhance manufacturing quality. Among the investigated curing strategies, the three-dwell cure cycle emerged as the most effective solution.

Improved photocatalytic degradation of methylene blue and rhodamine G dye under UV-radiation by rGO-MoO3

Abstract In this work, we report facile synthesis of rGO-MoO3 nanocomposites as photocatalysts via
one-step hydrothermal method. Initially, the synthesized materials were characterized by
different physicochemical methods to reveal the structural, morphological, optical, and other
properties. The transmission electron microscopy (TEM) and Raman spectroscopy results
validate the formation of rGO-MoO3 nanocomposites. The optical bandgap values of pristine
MoO3 (3.47 eV) and rGO-MoO3 (3.36 eV), reveal that they can serve as ultra-violet light
photocatalysts, for the decomposition of organic pollutants e.g. methylene blue (MB) and
rhodamine G (RhG) dye. The rGO-MoO3 nanocomposites significantly enhanced the
photodegradation efficiency as compared to MoO3, due to the interfacial interaction between
the composite parts and promote the transfer of charge carriers from MoO3 to rGO, causing a
reduced rate of electron-hole recombination. The highest degradation efficiency was observed
for rGO-MoO3 nanocomposite {for MB (~50%) and RhG (~96%)}, whereas for MoO3 {for
MB (~40%) and RhG (~43%)}. This report highlights a noteworthy impact of rGO with MoO3
nanocomposites as a photocatalyst.

Using Urban Residue in Polylactic Acid Composites Part I: Effect of Castor Oil on the Crystallization Kinetics

Using Urban Residue in Polylactic Acid Composites Part I: Effect of Castor Oil on the Crystallization Kinetics

Culinary Word Formation in Batak Toba Language: A Culinary Linguistic Analysis

This research aims to describe and formulate the formation of culinary words in the Batak Toba language (BTL). It is also hoped that the research can contribute to the revitalization of BTL lexicons, especially those related to culinary names. The approach in this research is a qualitative approach with ethnographic methods. The implementation of this research used the Spradley analysis model. The data were in the form of words and phrases taken from culinary names in BTL. The data were obtained through observation, documentation, and interview. The theory used as a reference in this research is by Gerhardt et al. (2013) who state that the linguistic word formation process is research based on food vocabulary and its meaning. From the research results, it was found that the internal word formation processes that commonly occur in the BTL include; (1) Composition, which consists of 6 (six) composition parts; (2) Reduplication, which consists of 5 (five) reduplication parts; and (3) Affixation, which consists of 4 (four) affixation parts. However, the amount of data on BTL culinary names in the formation of each reduplication is not much or in other words, it is not as productive as in the formation of words in composition.

Automating the hand layup process: On the removal of protective films with collaborative robots

This paper explores the issue of protective film removal in the hand layup process for composite parts production. The hand layup process, involving the assembly of prepreg plies onto a mold, is a skill-intensive task performed by multiple expert workers. A significant limitation of this method is its low repeatability, which impacts both the consistency and quality of the final product. The current research trend has the objective of developing autonomous or semi-autonomous layup cells to enhance process consistency, reduce production costs, and improve product quality.Despite all this interest in bringing automation in composite manufacturing, an area left relatively unexplored is the removal of protective films from prepregs. The plies used in the hand layup process, are generally covered by those films that are removed by the workers during the manual layup activity. The manual removal of protective films from prepregs is a tedious and valueless task, which represents a bottleneck in achieving full or semi-automation of the layup process. For this reason, an autonomous or semi-autonomous cell needs to perform it to be market-relevant.In this work, we propose a new effective method for initiating the peeling and integrate this method into a complete framework for the removal of protective films. This solution is designed to be easily integrated into a variety of existing cells. Finally, we validate our framework with an experimental proof of concept (PoC) which makes use of two collaborative robots for task execution.

Autumn diet of Little Owls (Athene noctua) in southern Tunisia

Abstract The Little Owl (Athene noctua) is a widespread nocturnal raptor whose diet has extensively been studied. In the Mediterranean, a tendency towards increased ingestion of insects has been highlighted, but this tendency still needs more empirical validation. Here, we provide data on the autumn diet of Little Owls in an arid area in southern Tunisia. We analyzed 621 pellets from 30 different territories and identified 4,267 prey items, with insects being by far the most ingested prey. However, based on biomass, the diet was more evenly distributed across the identified prey categories. Vertebrates accounted for 63% of the biomass ingested, while the remaining part of prey composition was almost equally shared between insects and arachnids. The importance of arachnids looks like a characteristic dietary trait of Little Owls in south Mediterranean deserts, where arachnids represent a main component of the community of potential prey. In summary, our findings highlight the great food opportunism of the Little Owl due to its capability of adapting its diet to the availability of potential prey.

Non-destructive examination of GFRP composite parts using active microwave thermography with water spraying

Abstract In this paper, in an attempt to non-destructively evaluate the Glass Fiber Reinforced Plastic (GFRP) composites, active thermography with microwave excitation is employed. Different types of defects including holes and cracks with different sizes were located in GFRP samples as well as specimens produced from PVC foams. Active Microwave Thermography (AMT) tests were performed from two different distances and with two different power levels. Moreover, the enhancement of detectability by the application of water spraying on the surface of the samples was investigated. The results indicated that active microwave thermography has better performance in the detection of holes compared with cracks. The application of water spraying significantly enhanced the detectability of surface cracks in the GFRP composites and PVC foam samples. Finite Element Analysis was employed to numerically simulate the microwave heating of the GFRP samples and evaluate the temperature variations. Statistical analyses were carried out to investigate the effect of test parameters on the detectability of defects. The statistical analysis results indicated that the heating time has a superior influence on the temperature contrast and detectability.

Life cycle assessment of coir fiber-reinforced composites for automotive applications

Past decades have seen an increasing prevalence of natural fiber-reinforced composites (NFRCs) due to growing conscientiousness around sustainability and a push towards vehicle lightweighting. The environmentally friendly and sustainable claims of NFRCs need to be validated due to their large variability and variety, particularly where material substitutions are concerned, such as in substituting glass fiber with natural fiber. The objective of this work is to determine the cumulative energy demand (CED) and greenhouse gas emissions (GHG) associated with an automotive part (of volume 0.001 m3) made from 40 wt% coir fiber-reinforced polypropylene (PP) and compared with a similar part made from 40 wt% glass fiber reinforced PP. SimaPro v. 9.0.0.49 was used for the analysis, whereas inventory data were collected from databases, such as Ecoinvent 3, Transportation Energy Databook, Greet model 2022, and published papers. The results showed that CED and GHG associated with the coir fiber-reinforced composite part were lower than the glass fiber-reinforced composite part for both cradle-to-gate (∼34-40%) and cradle-to-grave (excluding end-of-life) (∼24%) analysis.

Resistance Welding of Carbon Fiber Reinforced Vitrimer Composites

The welding behavior of prototype vitrimer composites with respect to adjustable parameters and protocols is investigated, and a method for resistance welding of vitrimer composites directly adapted from the welding of thermoplastic composites is described. Adherend laminates are positioned on either side of a matrix-saturated carbon fiber heating element, through which current is driven, and resistance heating welds the adherends and heating element together, forming a single lap joint. Weld strengths matched or exceeded the strength of composite parts produced using the manufacturer-recommended consolidation method (12.0 ± 2.6 MPa vs. 8.4 ± 0.6 MPa). Furthermore, repeating the welding process yielded greater shear strength, withstanding up to five weld–break–reweld cycles with an average increase of 4.6 ± 1.5 MPa or 65% compared to the first weld. The findings from resistance weld experiments highlight the suitability of vitrimer matrix composites for repair. Finally, a process for reversing a welded joint was shown, demonstrating the potential for vitrimers for temporary joining and rejoining.

Investigating physical and mechanical properties of alumina/acrylonitrile butadiene styrene composites manufactured by fused deposition modeling

AbstractIn recent years, 3D printing technologies or additive manufacturing have gained significant attention in research and other industries. Among the various 3D printing techniques, fused deposition modeling has been the most widely adopted. This study focused on developing composite filaments by incorporating acrylonitrile butadiene styrene (ABS) with different volume percentages of aluminum oxide (alumina). The mechanical and physical properties of parts printed with these composite filaments were thoroughly evaluated. Tensile testing revealed that increasing the alumina content led to a reduction in tensile strength. At 20 vol%, tensile strength dropped by 72%. A heat deflection temperature (HDT) test indicated an 11% reduction in HDT, likely due to the defective composite structure. Thermogravimetric analysis test demonstrated improved thermal stability as alumina content increased. Linear shrinkage was measured in three directions, revealing anisotropic shrinkage patterns. Hardness tests were conducted, and a decrease was observed when the polymer was filled with alumina. Finally, the warpage was reduced by 91% as alumina content increased to 20%.Highlights Alumina/ABS composite filaments were manufactured and 3D‐printed very well. The void content in composite samples increases with alumina powders. The mechanical properties of 3D‐printed composite parts were decreased The alumina powder improves the warpage issues in 3D‐printed parts.

Characterization and modelling of the microstructural and mechanical properties of additively manufactured continuous fiber polymer composites

The additive manufacturing of continuous fiber reinforced polymer composites is a technology showing great potential for the production of end-use functional and structural components. The reasons for its still limited use are primarily related to an insufficient knowledge of the mechanical behavior of these composites, especially when considering the features that distinguish the printed components from conventional composite parts. Among these peculiar features, their bead-based architecture has been experimentally and analytically investigated in this study. Following an analysis of the process-morphology correlation, carbon fiber (CF)/polyamide 12 (PA12) specimens were tested to characterize the in-plane quasi-static material properties. Then, a modelling framework has been proposed for assessing the composite elastic properties and average bead stresses. This framework holds the potential to scale up to a structural level, accommodating various fiber trajectories.

Harnessing Cattail Biomass for Sustainable Fibers and Engineered Bioproducts: A Review.

Cattail (Typha), a wetland plant, is emerging as a sustainable materials resource. While most of the Typha species are proven to be a fiber-yielding crop, Typha latifolia exhibits the broadest leaf size (5-30mm), yields highest amount of fiber (≈190.9g), and captures maximum CO2 (≈1270g). Alkaline retting is the most efficient degumming process for cattail fibers to achieve maximum fiber yield (30%-46%). Cattail leaves exhibit a distinctive bionic structural model consisting of epidermis and leaf blade at macro level and non-diaphragm aerenchyma, fiber cables, partitions, and diaphragms at micro level. Cattail fibers hold promise to be utilized as a high-performance composite part and as efficient energy storage devices in clean energy vehicles. The former is attributed to their lower density (≈1.26-1.39gm/cm3) and higher tensile modulus (≈66.1GPa after treatment), while the latter is attributed to their porous structure and chemical stability. Therefore, integrating the knowledge of plant biology and materials chemistry is crucial for enhancing fiber characteristics and producing engineered bioproducts. The environmental benefits of cattails, degumming methods, leaf and fiber structures, their properties and applications is reviewed. Finally, it discussed future research directions aimed at developing bioengineered, biodegradable products from it with minimal environmental impact.