Numerical modeling of thermal loading of composite aerospace vehicle parts containing cracks

The effect of fiber plasticity on domain formation in soft biological composites—Part I: A bifurcation analysis

Machine learning-aided network for process-property prediction of injection-molded polyamide-6 composite parts

In metal additive manufacturing, the molten pool directly influences the performance of the fabricated components. Therefore, a comprehensive understanding of the molten pool behavior is essential for improving the quality of the parts and mitigating the formation of defects. Selective arc melting (SAM) is a promising additive manufacturing method for fabricating metal matrix composites. However, the melting and solidification process of the powder layer under the arc heat source remains unrevealed. This study aims to elucidate the formation mechanisms of surface morphology during SAM processing and the influence of carbide addition on the melting and solidification behavior of Inconel 718 powder. In this study, thin-walled parts of Inconel 718 and TiC/Inconel 718 composite were fabricated and their microstructures were studied. The melting and solidification behavior of Inconel 718 and TiC/Inconel 718 composite during single-track single-layer deposition was investigated using high-speed photography. Focusing on the differences in the sidewall surface morphology of the Inconel 718 and TiC/Inconel 718 composite parts, the edge feature formation of the deposition track of both materials was studied. Furthermore, the formation mechanism of the differences in forming height at different positions of the deposition track was explored. The results indicate that the melted material in the molten pool of Inconel 718 mainly comes from the mass transport of the beads generated around the molten pool, while the liquid material in the molten pool of TiC/Inconel 718 composite mainly comes from the in situ powder melted under the arc center. During the melting process of Inconel 718 powder, beads at the edge of the heating area come into contact with the boundary of the molten pool and solidify in situ, forming protrusion features. The randomness in the bead size leads to different volumes of molten material at different positions within the same time, thereby causing variations in building height.

ABSTRACT This study innovatively proposes and fabricates a modular three‐dimensional (3D) biodegradable root‐anchoring structure (BRAS) (dimensions: 10.5 cm × 12.0 cm × 1.0 cm, α = 60°). It is designed to address the issue that seagrass seedlings are easily displaced by seawater erosion. Fluid–structure interaction (FSI) simulations demonstrate that this design effectively disperses fluid forces. Meanwhile, the design generates stable low‐speed wake flows. Additionally, it maintains deformation below 1 cm. The structure is manufactured via selective laser sintering (SLS) technology. Biodegradable polylactic acid/polycaprolactone (PLA/PCL) composite materials are used for fabrication. The study evaluated mass loss, pH changes, microstructure variations, and flexural strength. At a PCL content of 10 wt.%, the composite parts achieve an ideal balance between mechanical properties and controlled degradability. It can match the early establishment cycle of seagrass and provides a comprehensive systematic solution for coastal ecological restoration. This research holds significant implications for seagrass bed restoration and ecological balance maintenance.

Abstract Multiphase flow through porous media is a common phenomenon during the processing of composite materials in which viscous liquid thermoset resin containing small bubbles due to entrapped air is injected into reinforcing porous fibrous media. The composite part is formed once the resin cures. Entrapped bubbles cause porosity, which is characteristic of materials fabricated by this technique and results in reduced mechanical properties. Hence, the reduction in porosity during the processing stage remains a critical issue. To investigate this, an experimental study was conducted to characterize the movement of bubbles within the pore network of the fabric’s weave architecture representing the porous media. Bubble dynamics, as the simulated resin impregnated the fibrous network, were observed in transparent molds for three fabric architectures, with bubble diameter and velocity being measured as they traversed through the fabric. A dimensionless number is introduced to correlate the fabric weave architecture to the bubble size, revealing that higher bubble mobility (indicating how fast the bubble moves compared to the pore averaged resin velocity) is observed in tighter weaves and with larger bubbles. To predict bubble mobility based on bubble size and fabric weave, two physics-based models are introduced. The predicted results are compared with the experimental data, facilitating void minimization by regulating bubble mobility.

PETG (Polyethylene Terephthalate Glycol)-Carbon Fiber composites fabricated using fused deposition modeling are emerging as promising alternatives for lightweight UAV structures; however, their performance is strongly influenced by internal infill architecture and structural design. From an initial set of 21 infill patterns, five mechanically efficient patterns (Tri-Hexagon, Triangle, Support Cubic, Rectilinear, and Quarter Cubic) were shortlisted and evaluated through tensile, wear, impact, and hardness tests. Rectilinear infill exhibited the highest tensile strength (35N/mm2) and superior wear resistance under loads up to 30N, while Quarter Cubic showed comparable tensile performance (34N/mm2). Support Cubic infill demonstrated the highest impact energy absorption (6.5J), outperforming other patterns by more than 60%, whereas Tri-Hexagon and Rectilinear infills yielded the highest hardness values (73 Shore D). Based on this quantitative assessment, the Support Cubic pattern was selected for fabricating a full-scale PETG-carbon fiber drone frame using generative design. Drop tests revealed that the optimized frame withstood impacts up to 12m (23.5J), exceeding the failure threshold of a conventional carbon frame. This study identifies the support cubic infill as the best-performing architecture for PETG-carbon fiber composites, exhibiting superior tensile strength, impact resistance, and stiffness compared to other evaluated patterns, making it particularly suitable for lightweight UAV frame applications. These results demonstrate that strategic infill pattern selection enables PETG-carbon fiber composites to achieve application-specific mechanical advantages, offering a cost-effective and impact-resistant alternative for UAV frame structures.

Corrigendum to “A 3D interconnected CNT–RGO hybrid networks for Al matrix composites: Unveiling a new pathway to superior strength–ductility balance” [Composites Part B: Engineering 305 (2025) 112746

ACTS-3D: Advanced continuous tow shearing for manufacturing of defect-free 3D complex composite parts

An n-color composition is a colored composition in which a part of size m may come in m colors. This paper gives a new set of n-color-type compositions that admits exhaustive conjugation of its members. Previous attempts at conjugation of n-color compositions have yielded partial results at best. Instead of importing the coloring scheme previously used for partitions, we apply colors directly to the parts of compositions while treating any maximal string of ones as a single part under color assignment. This leads to the definition of n-color compositions of the second kind. As with ordinary compositions, a conjugate may be found using equivalent techniques: symbolic algebra, zig-zag graphs, and line graphs. We conclude with a derivation of the relevant enumeration formulas.

The prevalence of mechanical structures in industrial sectors has increased thanks to 3D printing technology. This technology requires fewer mechanical bonds to assemble structures, but challenges arise due to material differences and cost. One impactful approach to enhancing mechanical characteristics is to design sandwich structures. This study used ASA and ABS to produce a sandwich composite, exploiting each material's positive attributes. The mechanical properties of the composite sandwich plates were investigated to assess their use as structural parts. The outer parts of the sandwich structure are made of ASA material resistant to external factors and the inner part is made of ABS material with flexural strength. Layer thickness was utilised as a variable printing parameter. In the present study, tensile and flexural tests were conducted, with the objective of comparing the mechanical characteristics of components fabricated from pure ASA and ABS materials, and from sandwich composite parts. The findings of the study demonstrated that the maximum tensile strength of 33.18 MPa and the maximum flexural strength of 57.78 MPa were observed in the sandwich samples produced with an ASA/ABS/ASA layer thickness of 0.15 mm. The study is of significance to industries such as automotive and aviation, insofar as it explores the potential areas of use for functional sandwich structures produced from different materials and increases their use.

This paper focuses on the application of plastic-fiber composites in reducing the weight of small mechanical parts. With the development of industry, there is an increasing demand for lightweight mechanical parts. Plastic-fiber composites, due to their unique properties, have become a potential alternative to traditional metal materials. This research conducts a series of tests on plastic-fiber composites, replacing metal parts with composite parts and comparing their strength and weight reduction effects. The results show that plastic-fiber composites can achieve significant weight reduction while maintaining satisfactory strength, providing a new solution for the lightweight design of small mechanical parts.

ABSTRACT Additive manufacturing (AM) of composites is gaining popularity due to the ability to quickly 3D print tough and durable composite parts on demand. As carbon fiber (CF) is the most common reinforcement candidate for AM composite production parts, increasing the toughness and durability of 3D‐printed thermoset composites reinforced with continuous CF tow is of great importance. To this end, we adapted three tough low‐viscosity photocurable resin formulations consisting of a commercial urethane acrylate resin (a matrix system that bonds well with CF) and petrochemical ( N ‐vinylpyrrolidone, NVP) and bio‐derived (3,4‐dimethoxystyrene, VV) reactive diluents as matrices for AM of continuous CF composites in a custom 3D printing process. The resin formulations demonstrated high double bond conversion in the two‐step process consisting of photocuring and thermal postcuring. The mechanical properties of the AM composites showed distinction from the properties of urethane acrylate‐based composites reported in prior literature. In this study, these properties were compared as a function of reactive diluent in the formulations. The tensile properties of AM composites printed using the three resins were similar and fell within the expected range based on their fiber volume fraction. However, the flexural and fracture behavior of the resins was strongly dependent on the type of reactive diluent used. Aromatic VV increased flexural strength and modulus, whereas NVP, a cyclic lactam, resulted in enhanced ability of the composites to absorb and dissipate impact energy. Overall, the resins demonstrated their effectiveness as matrices in AM of continuous CF composites.

ABSTRACT Laminated fiber‐reinforced composites are widely used in structural applications, yet their performance deteriorates under harsh environmental and dynamic loading conditions. This study examines the low‐velocity impact behavior of glass fiber/epoxy composites aged in acidic conditions, with and without halloysite nanotube (HNT) reinforcement. After 42 days of immersion in an acidic medium, water absorption reached 9% in unmodified GFRP, whereas it remained limited to 4% in HNT‐reinforced composites (Ms‐GFRP). ICP–OES analysis further showed that Ms‐GFRP released substantially fewer dissolved elements into the solution, confirming its enhanced chemical stability. Low‐velocity impact tests demonstrated that HNT addition significantly improved impact resistance under all aging durations. After 14 days of acidic exposure, Ms‐GFRP exhibited 34%–40% higher peak load capacity than GFRP at impact velocities of 2, 2.5, and 3 m/s, with similar trends observed after 28 and 42 days. Deflection values after 42 days increased by 24%–49% in Ms‐GFRP, compared to 34%–49% in GFRP, indicating reduced structural degradation. Likewise, the reduction in energy absorption remained slightly lower in Ms‐GFRP (up to 43%) than in GFRP (up to 45%). The results demonstrate that HNT reinforcement enhances both the mechanical integrity and environmental durability of glass/epoxy composites by mitigating moisture diffusion and acid‐induced degradation. These findings highlight Ms‐GFRP as a promising material for applications requiring improved resistance to corrosive environments and impact loading.

Mirrored in-situ consolidation of CF/PEEK composite parts using a pixelated mirror heating tool

Edge tools, such as drills, milling cutters, and turning tools, are increasingly used in the manufacture of parts made of 3D woven fiber-reinforced composite materials. The cutting process of non-rigid workpieces, such as turbine blades, is accompanied by noticeable elastic displacements which reduce the machining accuracy. To calculate cutting forces, chip formation should be simulated in the cutting zone, which significantly depends on the orientation of the workpiece fibers relative to the wedge of the cutting tool. Since workpiece deformations should be calculated selectively at separate points of the toolpath, the corresponding fragments of the workpiece with the specific fiber arrangement should be determined for cutting modelling. For this purpose, we need to develop a finite element model of the entire workpiece taking into account fibers and boundary layers and calculate the stress-strain state in the cutting zone during chip formation in the selected workpiece fragments. This research allowed solving these issues. We obtained mathematical relations for voxel modeling of the specified composite parts and calculation of their finite elements and developed computer programs to obtain the necessary geometric and physical models of chip formation mechanics. The calculations confirmed that the proposed numerical solutions are sufficient enough to be used by industrial production technologists to predict the accuracy of processing small-sized composite parts.

We conducted a study aimed at studying the impact of genetic variation in the DGAT1 gene (diacylglycerol O-acyltransferase 1) on the growth rates and meat characteristics of Kalmyk bulls. The study was conducted on Kalmyk bulls in the Republic of Kalmykia, at the Uralan Agrofirm LLC. The analysis of genotypes showed that the dominant genotype is KK (43.39%), while the AA genotype is significantly less common (17.32%). The frequency of the K allele exceeds the frequency of the A allele by 26%. The analysis of the influence of the DGAT1 gene revealed that bulls with the DGAT1AA genotype demonstrate improved slaughter qualities. They exceed individuals with the DGAT1KK genotype in terms of pre-slaughter weight by 3.1 kg (0.81%), in terms of fresh carcass weight by 2.4 kg (1.12%), in terms of carcass yield by 0.1%, and in terms of slaughter weight by 2.2 kg (0.96%). At the same time, the carcasses of bulls with DGAT1KA and DGAT1KK genotypes had a higher crude fat mass than those of animals with DGAT1AA genotype, with an excess of 0.1 kg (0.63%) and 0.2 kg (1.27%), respectively. When studying the composition of carcasses, it was found that the highest amount of muscle tissue was obtained from young animals with DGAT1AA genotype. Their advantage over peers with DGAT1KK and DGAT1KA genotype was 1.1-1.3 kg (1.26%-1.50%). High indicators of cut weight were revealed in steers with DGAT1AA genotype, in comparison with DGAT1КA and DGAT1KK analogues the difference was: In cervical, 0.2 kg (2.02%) and 0.3 kg (3.06%); in brachial, 0.2 kg (1.24%) and 0.4 kg (2.52%); in spinal, 0.2 kg (0.57%) and 0.3 kg (0.86%); In the lumbar, 0.1 kg (1.15%) and 0.2 kg (2.33%); in the hip, 0.1 kg (0.28%) and 0.2 kg (0.56%), respectively. In the study of morphological composition and natural anatomical parts, it was found that animals with DGAT1AA genotype produced more meaty carcasses than their counterparts with DGAT1КA and DGAT1KK genotypes.

Purpose The purpose of this paper is to develop a versatile extrusion system for solid-based additive manufacturing (AM) that overcomes the limitations of using only filament or pellet extrusion. By combining both in one setup, the study targets enhanced material compatibility, flexible part production and improved printing performance. It addresses the growing need for adaptable AM systems capable of processing polymers in various forms and delivering better print quality, particularly in multi-material and flexible applications. Design/methodology/approach This study introduces a novel multi-material co-extruder system that integrates both pellet and filament extrusion mechanisms into a single setup. The system is designed to process a wide range of industrial polymers – especially those available only in pellet form – enabling flexible, high-quality and multi-material AM. Case studies were conducted to validate the system’s performance in producing flexible parts with improved surface finish and customized material distribution. Findings The developed co-extruder system demonstrated the ability to process both filament and pellet-based materials efficiently. The system enabled high-speed, cost-effective production of flexible and multi-material components with superior surface quality – recording a 19.76% reduction in average surface roughness compared to filament-only prints. In composite (PLA+TPU) parts, the co-extruder achieved intermediate mechanical properties with elongation of 303% and hardness of 71 Shore D (between PLA: 6% elongation, 84 Shore D and TPU: 452% elongation, 52 Shore D). These results confirm the system’s ability to tailor material behavior and minimize staircase effects commonly observed in layer-by-layer AM processes. Originality/value This research presents an original contribution by introducing a dual-mode extrusion system capable of handling both pellet and filament materials within a single AM setup. Unlike conventional systems, this approach facilitates customized material blending and part flexibility, making it suitable for a broader range of applications. The system offers a unique solution for industries requiring material adaptability, high-quality surface finishes and reduced post-processing. Its innovative design also paves the way for more sustainable and cost-effective AM solutions.

One of the main problems in designing composite structures is the creation of reliable fastening methods, since traditional drilled holes destroy load-bearing fibers, leading to significant stress concentration and reduced strength. The aim of this work is to develop and illustrate a bio-inspired method for fastening composite parts by creating a curved reinforcement structure that mimics the knot zone in wood. It is shown that an iterative algorithm for computer modeling of fiber trajectories «flowing» around the hole, allows the construction of a reinforcement structure in which the «fiber overload coefficient» is only 1.3 instead of a stress concentration coefficient of about five in a unidirectional carbon fiber plate with a circular hole. Experiments on wooden samples with removed knots and drilled holes, as well as on composite samples with curved reinforcement made using 3D printing, confirmed the effectiveness of the proposed approach. Preserving the reinforcement structure in the knot area means that the hole from the removed knot does not affect the strength at all, and failure occurs away from the hole. The results confirm the promise of using bio-like joints to significantly increase the load-bearing capacity and durability of composite fasteners, which is especially important for large aerospace structures.

Ethiopia’s diverse agroecological zones support a wide range of wild edible plants (WEPs) that grow naturally without cultivation. As part of the Eastern Afromontane and Horn of Africa biodiversity hotspots, the country hosts rich plant diversity with significant nutritional and ecological value. These important resources are poorly documented, and limited efforts exist to domesticate them or raise awareness about their mineral composition and edible plant parts among local communities. This review synthesises findings from ethnobotanical studies to examine WEP diversity, commonly consumed plant parts and their mineral composition, based on extensive literature from journal articles, manuals and reports. A total of 179 WEP species belonging to 49 families were identified. Moraceae was the most abundant family (16 species), followed by Fabaceae and Asteraceae (10 species each). Solanaceae, Rhamnaceae and Amaranthaceae contributed eight species each, while Anacardiaceae and Tiliaceae had seven species. These plants are consumed in multiple forms, including raw ripe fruits (48.6%), medicinal preparations (26.3%), fodder (17.3%), cooked leaves (3.4%), dried fruits, chewing gums, raw leaves and nectar. Growth habit analysis showed that trees accounted for the highest proportion (40.8%), followed by shrubs (27.4%) and herbs (23.5%). Mineral analysis of ten species revealed notable nutrient levels: Ziziphus spina-christi contained the highest calcium (1304.6 mg/kg), Cordia monoica had the highest phosphorus (76,461.7 mg/kg), and Urtica simensis had the highest iron (316 mg/g). Macronutrient assessments of five species showed that Dioscorea praehensilis had the highest carbohydrate content (83.8%), whereas Talinum madagascariense had the highest energy value. Solanum nigrum and Cleome gynandra exhibited superior protein and fibre levels. Despite their nutritional and economic importance, WEPs face increasing threats from agricultural expansion, deforestation, overgrazing, charcoal production and recurrent drought. Enhancing conservation efforts, raising community awareness and promoting sustainable use and domestication of priority species are crucial for improving food security, nutrition and biodiversity conservation in Ethiopia.