Search Results (1,701)

This study investigates the Mode II fracture behavior of bamboo–coir–rubber (BCR) hybrid composite panels developed as sustainable alternatives for wood-based panels used in structural applications. The composites were fabricated using alternating bamboo and coir layers within a polypropylene (PP) thermoplastic matrix, with styrene–butadiene rubber (SBR) incorporated as an additive at 0–30 wt.% to enhance interlaminar toughness. Commercial structural plywood was tested as the benchmark. Mode II interlaminar fracture toughness (G_IIc) was evaluated using the ASTM D7905 End-Notched Flexure (ENF) test, supported by optical monitoring to study crack monitoring and Scanning Electron Microscopy (SEM) for microstructural interpretation. Results demonstrated a steady increase in G_IIc from 1.26 kJ/m² for unmodified laminates to a maximum of 1.98 kJ/m² at 30% SBR, representing a 60% improvement over the baseline and nearly double the toughness of plywood (0.7–0.9 kJ/m²). The optimum performance was obtained at 20–25 wt.% SBR, where the laminated retained approximately 85–90% of their initial flexural modulus while exhibiting enhanced energy absorption. Increasing the initial notch ratio (a₀/L) from 0.2 to 0.4 caused a reduction of 20% in G_IIc and a twofold rise in compliance, highlighting the geometric sensitivity of shear fracture to the remaining ligament. Analysis of Variance (ANOVA) confirmed that the increase in G_IIc for the 20–25% SBR laminates relative to plywood and the unmodified composite is significant at p < 0.05. SEM observations revealed rubber-particle cavitation, matrix shear yielding, and coir–fiber bridging as the dominant toughening mechanisms responsible for the transition from abrupt to stable delamination. The measured toughness levels (1.5–2.0 kJ/m²) position the BCR panels within the functional range required for reusable formwork, interior partitions, and transport flooring. The combination of renewable bamboo and coir with a thermoplastic PP matrix and rubber modification hence offers a formaldehyde-free alternative to conventional plywood for shear-dominated applications. Full article

Due to their sustainability, lightweight qualities, and simplicity of installation, wood slab systems have gained increasing attention in the building industry. Cross-laminated timber (CLT), an engineered wood product (EWP), improves structural strength and stability, offering a good alternative to conventional reinforced concrete (RC) slab systems. Conventional CLT, however, contains adhesives that pose environmental and end-of-life (EOL) disposal challenges. Adhesive-free CLT (AFCLT) panels have recently been introduced as a sustainable option, but their environmental performance has not yet been thoroughly investigated. In this study, the environmental impacts of five slab systems are evaluated and compared using the life cycle assessment (LCA) methodology. The investigated slab systems include a standard CLT slab (SCLT), three different AFCLT slabs (AFCLT1, AFCLT2, and AFCLT3), and an RC slab. The assessment considered abiotic depletion potential (ADP), global warming potential (GWP), ozone layer depletion potential (ODP), human toxicity potential (HTP), freshwater aquatic ecotoxicity potential (FAETP), marine aquatic ecotoxicity potential (MAETP), terrestrial ecotoxicity potential (TETP), photochemical oxidation potential (POCP), acidification potential (AP), and eutrophication potential (EP), covering the entire life cycle from production to disposal, excluding part of the use stage (B2-B7). The results highlight the advantages and drawbacks of each slab system, providing insights into selecting sustainable slab solutions. AFCLT2 exhibited the lowest environmental impacts across the assessed categories. On the contrary, the RC slab showed the highest environmental impact among the studied products. For example, the RC slab had the highest GWP of 67.422 kg CO₂ eq, which was 1784.3% higher than that of AFCLT2 (3.779 kg CO₂ eq). Additionally, the simulation displayed that the analysis results vary depending on the electricity source, which is influenced by geographical location. Using the Norwegian electricity mix resulted in the most sustainable outcomes compared with Sweden, Finland, and Saudi Arabia. This study contributes to the advancement of low-carbon construction techniques and the development of building materials with reduced environmental impacts in the construction sector. Full article

Asymmetric and symmetric magnetoelectric (ME)-laminated composites with magnetostrictive layer FeNi and piezoelectric layer PZT are prepared. The longitudinal resonance ME voltage coefficient in the symmetric composite is approximately 1.57 times that in the asymmetric composite with same constituents due to the flexural deformation and asymmetric stress distribution in the asymmetric structure. By bonding an additional high-permeability FeSiB, combining FeSiB with FeNi forms magnetization-graded ferromagnetic materials. A stronger maximum ME voltage coefficient, a dual-peak phenomenon, and a self-bias ME effect are observed. The maximum ME voltage coefficients for asymmetric and symmetric composites reach 3.10 V/Oe and 5.67 V/Oe by adjusting the thickness of the FeCuNbSiB layer. The maximum zero-bias ME voltage coefficients for asymmetrical and symmetrical composite materials reach 2.19 V/Oe at 25 µm thickness of FeSiB and 2.87 V/Oe at 75 µm thickness of FeSiB. Such high performances enable the ME composites to possess ideal sensing and make them promising for self-bias current sensor applications. Full article

Piezoelectric composites have found a wide range of applications in smart structures and devices and effective numerical methods should be developed to simulate not only the macroscopic coupled piezoelectric performances, but also the details of the local distributions of the stress and electric field. In this paper, we proposed a multi-scale asymptotic algorithm based on the Second-Order Two-Scale (SOTS) analysis method for the piezoelectric eigenvalue problem in perforated domain with periodic micro-configurations. The eigenfunctions and eigenvalues are expanded to the second-order terms and the homogenized eigensolutions; the expressions of the first- and second-order correctors are derived successively. The first- and second-order correctors of the eigenvalues are determined according to the integration forms of the correctors of the corresponding eigenfunctions. Explicit expressions of the homogenized material coefficients are derived for the laminated structures and the finite element procedures are proposed to compute the homogenized solutions and the correctors numerically. The error estimations for the approximations of eigenvalues are proved under some regularity assumptions and a typical numerical experiment is carried out for the two-dimensional perforated domain. The computed results show that the SOTS analysis method is efficient in identifying the piezoelectric eigenvalues accurately and reproducing the original eigenfunctions effectively. This approach also provides an efficient computational tool for piezoelectric eigenvalue analysis and can extend to other multi-physics problems with complex microstructures. Full article

As a green-material structure, cross-laminated timber (CLT) has attracted increasing attention and applications in construction. This study presents an analytical model for a CLT plate under the coupling effect of load and moisture content, where the moisture-induced deformation and moisture-dependent properties are both considered. In the analytical model, state-space equations for moisture variables and for stresses and displacements in the CLT plate are established based on moisture diffusion theory and three-dimensional elasticity theory, respectively. Using the transfer matrix method, the relationships of moisture variables, stresses, and displacements between any two layers of the CLT plates are formulated. The analytical solutions are then determined by the load and moisture conditions applied to the top and bottom surfaces. Comparative analysis indicates that the proposed solution surpasses finite element methods in both computational accuracy and efficiency. In addition, the stress and displacement patterns of CLT plates under pure load and pure moisture conditions, as well as their interrelations, are investigated through a decoupled analysis. An applicable modified superposition principle is then proposed. Finally, a detailed parametric study is conducted to examine the effects of moisture distribution and wood species. Full article

Recent comprehensive research (2023–2024) on basalt fiber-reinforced composites (BFRCs) has meticulously documented significant progress across diverse applications, including protective coatings, high-performance concrete, reinforcement bars, and advanced laminates. The central theme of these developments revolves around innovative composite design strategies that strategically incorporate basalt fibers to markedly enhance mechanical properties, durability, and protective capabilities against environmental challenges. Key advancements in synthesis methodologies highlight that the integration of BFs substantially improves abrasion and corrosion resistance, effectively inhibits crack propagation through superior fiber-matrix bonding, and confers exceptional thermal stability, with composites maintaining structural integrity at temperatures of 600–700 °C and demonstrating short-term resistance exceeding 900 °C. The underlying mechanisms for this enhanced performance are attributed to both chemical modifications—such as the application of silane-based coupling agents which improve interfacial adhesion—and physical–mechanical interlocking between the fibers and the matrix. These interactions facilitate efficient stress transfer, leading to a breakthrough in the overall multifunctional performance of the composites. Despite these promising results, the field continues to grapple with challenges, particularly concerning the long-term durability under sustained loads and harsh environments, and a notable lack of standardized global testing protocols hinders direct comparison and widespread certification. This review distinguishes itself by offering a critical synthesis of the latest findings, underscoring the immense application potential of BFRCs in critical sectors such as civil engineering for seismic retrofitting and structural strengthening, the automotive industry for lightweight yet robust components, and advanced passive fireproofing systems. Furthermore, it emphasizes the growing, innovative role of simulation techniques like finite element analysis (FEA) in predicting and optimizing the performance and design of these composites, thereby providing a robust scientific foundation for developing the next generation of high-performance, sustainable structural components. Full article

Previous research shows that thin-ply composite materials offer superior static and fatigue characteristics to standard laminates used in aviation. Therefore, they are expected to be capable of significantly contributing to a mass reduction needed to improve the energy-efficiency of future aircraft. However, so far, thin-ply composites have only been employed in special applications. Quantitative full-scale assessments of the benefits on the level of global aircraft structures are missing. This study employs a parametric, finite element-based tool chain with a fully-stressed design methodology to investigate potential benefits from the use of thin plies, which may result from increased strength, an extended design freedom and stability considerations, in a generic wing structure of a conceptual medium-range aircraft in order to reduce this research gap. The methodology is validated using an academic test case. Naturally, mass reductions from strength enhancements are limited by buckling constraints in thin-walled structures. However, for the wing examined in this study, an increase in strength of 10% still yields up to a 7.9% reduction in global wing mass, while an increase of 20% results in mass savings of up to 13.4%. The use of thin-ply composites may allow for reducing minimum wall thickness constraints. Associated mass savings of up to 3.1% found in this study on global wing level when alleviating the requirement from 2.4 $\mathrm{m}$$\mathrm{m}$ to 1.2 $\mathrm{m}$$\mathrm{m}$ are, however, restricted to rib mass and may better be achieved by different means such as topology optimisation. In contrast, mass penalties from the application of a simplified manufacturing constraint are reduced significantly from beyond 10% on global wing level for plies with a thickness of 0.175 $\mathrm{m}$$\mathrm{m}$ to approximately 1.5% with a ply thickness of 0.05 $\mathrm{m}$$\mathrm{m}$. Full article

This work presents the development and characterization of laminated composite panels produced from açaí residues and fibers, incorporated into a castor oil-based vegetable polyurethane matrix. The study aimed to evaluate the potential of these Amazonian agro-industrial residues as lignocellulosic reinforcement in sustainable materials. The manufacturing process was carried out by manual lamination and cold pressing, following the recommendations of ABNT NBR 14810-2:2018. The physical (moisture, density, and swelling) and mechanical (perpendicular tensile and static flexural) properties of the resulting panels were analyzed. The results revealed an average moisture content of 6.23% and a 24 h swelling of 2.76%, which are values within and well below the regulatory limits, respectively. The perpendicular tensile strength (0.49 N/mm²) exceeded the minimum required value, indicating good interfacial adhesion and internal cohesion. However, the flexural strength and modulus of elasticity (2.4 N/mm² and 1323 N/mm²) were below the standards due to the absence of oriented fibers and density heterogeneity. It is concluded that the composite has high potential for indoor applications with low structural stress, standing out for its lightness, dimensional stability and environmental viability in the use of açaí residues. Full article

The objective of this article is to evaluate the viability of implementing the Design for Manufacturing and Assembly (DfMA) methodology in the design and construction of complex wooden structures with non-standard geometry. The present study incorporates an analysis of scientific literature from 2011 to 2024, in addition to selected case studies of buildings constructed using glued laminated timber and engineered wood prefabrication technology. The selection of examples was based on a range of criteria, including geometric complexity, the level of integration of digital tools (BIM, CAM, parametric design), and the efficiency of assembly processes. The implementation of DfMA principles has been shown to result in a reduction in material waste by 15–25% and a reduction in assembly time by approximately 30% when compared to traditional construction methods. The findings of the present study demonstrate that the concurrent integration of design, production, and assembly in the timber construction process enhances energy efficiency, curtails embodied carbon emissions, and fosters the adoption of circular economy principles. The analysis also reveals key implementation barriers, such as insufficient digital skills, lack of standardization, and limited availability of prefabrication facilities. The article under scrutiny places significant emphasis on the pivotal role of DfMA in facilitating the digital transformation of timber architecture and propelling sustainable construction development in the context of the circular economy. The conclusions of the study indicate a necessity for further research to be conducted on quantitative life cycle assessment (LCA, LCC) and on the implementation of DfMA on both a national and international scale. Full article

This study evaluates the effect of chemical treatments on the short-beam shear strength, vibrational, and acoustic performance of banana-fibre-reinforced carbon–Kevlar hybrid composites. Banana fibres were treated with 5% NaOH and 0.5% KMnO₄ to improve fibre surface characteristics and interfacial bonding within a sandwich laminate of carbon–Kevlar intraply skins and banana fibre core fabricated by hand lay-up and compression moulding. Short-beam shear strength (SBSS) increased from 14.27 MPa in untreated composites to 17.65 MPa and 19.52 MPa with KMnO₄ and NaOH treatments, respectively, due to enhanced fibrematrix adhesion and removal of surface impurities. Vibrational analysis showed untreated composites had low stiffness (7780.23 N/m) and damping ratio (0.00716), whereas NaOH treatment increased stiffness (9480.51 N/m) and natural frequency (28.68 Hz), improving rigidity and moderate damping. KMnO₄ treatment yielded the highest damping ratio (0.0557) with reduced stiffness, favouring vibration energy dissipation. Acoustic tests revealed KMnO₄-treated composites have superior sound transmission loss across low to middle frequencies, peaking at 15.6 dB at 63 Hz, indicating effective acoustic insulation linked to better mechanical damping. Scanning electron microscopy confirmed enhanced fibre impregnation and fewer defects after treatments. These findings highlight the significant role of chemical surface modification in optimising structural integrity, vibration control, and acoustic insulation in sustainable banana fibre/carbon–Kevlar hybrids. The improved multifunctional properties suggest promising applications in aerospace, automotive, and structural fields requiring lightweight, durable, and sound-mitigating materials. Full article

The growing adoption of laminated fiber-reinforced polymer (FRP) composites in aerospace, automotive, and civil engineering demands advanced design methodologies capable of navigating their complex anisotropic behavior. While traditional design approaches rely heavily on iterative simulations and classical optimization, recent advances in artificial intelligence (AI) offer a transformative alternative. This review systematically examines the expanding role of AI in composite design and optimization—highlighting a critical transition from physics-based modeling to data-driven, intelligent frameworks. This paper emphasizes emerging AI paradigms not yet widely covered in the composite literature, including Explainable AI (XAI) for interpretable decision-making and Large Language Models (LLMs) for automating design synthesis and knowledge retrieval. Key findings demonstrate AI’s capacity to efficiently optimize stacking sequences, ply orientations, and manufacturing parameters while satisfying multi-objective constraints such as weight, stiffness, and damage tolerance. Furthermore, we explore AI’s integration across the composite lifecycle—from surrogate-assisted finite element analysis and uncertainty-aware design allowables to in-service structural health monitoring. By bridging the gap between computational intelligence and industrial practicability, this review underscores AI’s potential not as a supplementary tool, but as a foundational technology poised to redefine next-generation composite engineering. Full article

As a new type of bridge deck skin material, tiled laminates (TLs) are often subjected to bending actions in actual working conditions. This study employs a 3D progressive damage model (3D PDM) based on the Hashin damage criterion to investigate the influence of overlap configuration and inclination angle on the bending performance of tiled laminates in both elastic and non-linear stages through three-point bending (3PB) numerical simulations. The results indicate that, in the elastic stage, overlapped TLs (TLOs) exhibit a more uniform stress distribution due to their more rational geometric structure, and their bending stiffness is significantly less sensitive to the inclination angle compared to the non-overlapped TLs (TLNs). In the non-linear stage, damage in both configurations begins at the reduced section, and the ultimate midspan bending moment decreases with increasing inclination angles. Notably, cracks in the TLO configuration extend internally, enabling the structure to maintain a partial bending resistance up to failure, whereas cracks in the TLN configuration propagate externally, resulting in a rapid complete loss of structural bending performance. Furthermore, regardless of the geometric configuration and inclination degree, the final failure of the TL under bending is dominated by tensile failure. This research provides comprehensive insights into the bending mechanical behaviour of tiled laminates, offering scientific foundations for their optimised engineering design. Full article

This paper presents the findings of an experimental study on the structural response of glass fiber-reinforced polymer (GFRP)-concrete composite beams. The connectors were fabricated from GFRP dowels, epoxy resin-saturated E-glass roving, and/or adhesive layers. The composite beams were subjected to a four-point bending test configuration and examined for their failure modes and load-deformation characteristics. The test results showed that the developed configurations of composite beams significantly outperformed the response of the standalone GFRP I-section profile and non-composite beams. The provision of a discrete interfacial connection successfully prevented the local and lateral torsional buckling of the profile, doubled the initial stiffness, increased the load-carrying capacity by around three times, and imparted a certain degree of ductility and reserve capacity to the otherwise brittle system. The failure occurred primarily due to the shearing of the web. Other modes of failure were observed in the form of the cracking/crushing of concrete, delamination of the laminate, and buckling/crushing of the web. The epoxy-bonded composite beams displayed the highest stiffness, while those with 45° inclined dowels exhibited the highest load-carrying capacity. The results were compared against those predicted by the available analytical expressions, and required modifications are suggested. Full article

The Yingxiongling structural zone in the Qaidam Basin is a critical yet challenging target for shale oil exploration due to strong reservoir heterogeneity and complex sedimentary cycles. This study employs an integrated methodology combining laboratory rock mechanical tests, field fracturing diagnostics, and tracer data to evaluate the fracturing performance of dominant lithofacies. Results indicate that: (1) Laminated dolomitic limestone exhibits higher mechanical strength and requires elevated fracturing pressure compared to laminated shale, but contains inferior hydrocarbon content. In contrast, laminated shale develops more uniform and complex fracture networks post-fracturing. (2) A lower microseismic b-value in laminated dolomitic limestone suggests shear-dominated failure along bedding planes, enhancing micro-fracture development. (3) Pressure decline analysis and microseismic monitoring confirm that laminated shale facilitates higher fracture network complexity. In conclusion, laminated shale is identified as the preferred lithofacies in the Yingxiongling area, as it possesses a superior potential for generating complex fracture networks that meet the technical requirements for effective volume stimulation. Full article

Lacustrine fine-grained sediments commonly exhibit well-developed laminations, with significant variations in structural characteristics such as thickness and continuity, which are closely related to depositional environments and genetic processes. This paper focuses on the characteristics and formation mechanisms of the upper Es4 to lower Es3 members of the Shahejie Formation in the Dongying Sag. Through polarized light microscopy, field-emission environmental scanning electron microscopy (FE-SEM), electron probe microanalysis (EPMA), and X-ray diffraction (XRD), we systematically analyzed the types, characteristics, and genetic mechanisms of laminations in fine-grained sedimentary rocks. Results indicate that the mineral composition of these rocks is dominated by carbonates and clay minerals, allowing classification into calcareous and argillaceous mudstones. The types of laminae include calcareous laminae, argillaceous laminae, and silty laminae, which are formed by chemical precipitation, suspension settling, and low-density turbidity currents, respectively. The primary lamination associations are argillaceous–calcareous interbeds and argillaceous–silty interbeds, exhibiting rhythmic cyclicity. In the upper Es4 member, variations in climate, sediment supply, and seasonal factors caused fine-grained sediments to transition from flocculent suspension settling to chemical precipitation, forming periodic intercalations of argillaceous and calcareous laminae. In the lower Es3 member, seasonal turbidity currents triggered the deposition of normally graded silty layers and fine-silty laminae, followed by a return to suspension deposition, resulting in argillaceous–silty interbeds. This study reveals diverse transport and depositional mechanisms of fine-grained sediments under varying hydrodynamic conditions. It provides a new case for understanding the genesis of fine-grained sedimentary rocks and offers geological insights for shale oil exploration and development in the Dongying Sag. Full article