Search Results (540)

To address safety issues caused by the bottom impact of the power battery in new energy vehicles, a lightweight bottom panel design scheme based on long glass fiber-reinforced polypropylene (LGF/PP) honeycomb composite was proposed. By employing the sandwich structure with an LGF/PP surface material/polypropylene honeycomb core combined with high-shear-strength structural adhesive bonding technology, ball impact protection for the power battery bottom is greatly improved. A ball striking test was carried out in accordance with the requirements and test methods of bottom anti-collision for pure electric passenger vehicles (T/CSAE 244-2021), and the performance differences of traditional steel bottom guards were compared. The results show that the optimized honeycomb composite bottom guard plate (surface thickness 1.3 mm/honeycomb core 8 mm) is able to reduce the deformation of the aluminum plate to 10.4 mm, resulting in deformation that is only 68% of that observed with the steel bottom guard plate while achieving a 43% reduction in weight. The deformation of the aluminum plate was further reduced to 42.3% with the introduction of a structural adhesive with a 5 MPa shear strength. In addition, the honeycomb structure exhibits controllable plastic deformation after impact, while the steel bottom guard plate is severely distorted but not ruptured, highlighting the damage tolerance and energy absorption advantages of the composite material design. The honeycomb composite bottom guard plate outperforms the traditional scheme in terms of light weight, protection performance and cost. This work contributes to the field of power battery bottom protection. Full article

Ozonation is one of the most widely used methods for wastewater treatment. However, it suffers from several drawbacks, including a low reaction rate, long reaction time, and the formation of intermediate byproducts due to incomplete oxidation. Therefore, in this paper, the ozonation process was improved via the MgO nanocatalyst and honeycomb activated carbon (HAC) as a packing material in the bubble column reactor by using the following methods: (O₃/MgO, O₃/HAC, and O₃/MgO/HAC). The results showed that using ozone alone yielded a low chemical oxygen demand (COD) removal efficiency of 63.33% after 90 min, and the phenol concentration was 15 mg/L. However, when the catalyst was added, the efficiency increased to 73.33%, which is attributed to the enhanced generation of more hydroxyl radicals (OH•). The HAC packing material had a positive effect, as the removal efficiency rose to 76.66% due to its effective role in improving the mass transfer inside the reactor. The integrated (O₃/MgO/HAC) method proved to be the most effective at achieving a COD removal efficiency of about 83%; furthermore, the efficiency reached 91% when the initial phenol concentration decreased to 10 mg/L. Two doses of catalysts were used, 0.05 and 0.1 g/L, and it was found that the higher dose (0.1 g/L) had the highest efficiency. The effect of the initial phenol concentration and ozone gas flow rate were studied. The study concludes that the use of the MgO nanocatalyst and the honeycomb-structured activated carbon packing material plays an effective role in improving the ozonation process by increasing the reaction rate, reducing treatment time, and decreasing the demand for additional ozone gas supplies, thus achieving significant economic benefits. Full article

Future lunar missions, like the International Lunar Research Station (ILRS), demand single-launch multi-point operations, urgently requiring reusable energy-absorbing structures. Integrating shape memory alloy (SMA) into honeycombs offers a promising solution; however, deformation exceeding the SMA’s recoverable limit induces structural residual deformation, altering the configuration and degrading subsequent energy absorption. To address this, we propose a semi-analytical, data-calibrated hybrid model predicting SMA honeycomb residual deformation. A four-stage linear constitutive model is established capturing superelasticity and martensitic yielding. Cell walls are idealized as equivalent beams. Using layered fiber integration and numerical interpolation, a nonlinear moment–curvature relationship is constructed, enabling rapid structural residual deflection evaluation from material residual strains. Finite element results confirm that initial residual deformation stabilizes the honeycomb into a reusable configuration, governing subsequent plateau stresses. Calibrated by uniaxial test data, the proposed model accurately predicts residual deformation ratios and reusable plateau stresses with errors within 8%. By bridging material-level strain with structural-level deformation, this approach circumvents computationally expensive full-scale simulations and costly experimental trials, providing a highly efficient tool for designing reusable SMA absorbers. Full article

Magnetostrictive sensors based on the inverse magnetostrictive effect offer the advantages of wireless passive operation and structural simplicity; however, achieving both high sensitivity and superior linearity remains a persistent challenge. This study presents a magnetostrictive pressure sensor incorporating a tunable Poisson’s ratio (TPR) chiral auxetic honeycomb substructure, designed to linearize the stress response of the sensing material. A theoretical model linking substructure design parameters to sensor output linearity was derived and validated through finite element simulations. The fabricated substructure exhibited a stable negative Poisson’s ratio (−1.278 to −1.213) within its elastic regime and a highly linear axial-to-transverse strain relationship (x = 1.214y + 0.113). The sensor achieved a calibration linearity of R² = 0.99745, a continuous linear force response up to 118.7 N while the corresponding voltage variation reached 10.75 mV, and a maximum hysteresis error of 5.495% over eight loading cycles. Bearing press-fit force monitoring experiments confirmed practical viability under industrial conditions, with R² exceeding at least 0.995 for dry assembly between multiple bearing types and maintaining R² > 0.994 under lubricated conditions. The proposed TPR substructure approach establishes a reference framework for linearity enhancement in inverse magnetostrictive force sensors. Full article

In recent years, oil spill accidents and oily wastewater discharge have posed severe threats to aquatic ecosystems and human health. Developing green, low-cost, efficient, and recyclable oil–water separation materials is therefore important for environmental remediation. In this work, kaolin/cellulose composite aerogels were fabricated through a low-temperature NaOH/urea dissolution system using N,N′-Methylenebisacrylamide (MBA) as the cross-linking agent, followed by freeze-drying and hydrophobic modification with Methyltrimethoxysilane (MTMS). The structure, morphology, thermal stability, wettability, mechanical behavior, oil adsorption capacity, and reusability of the aerogels were systematically investigated. The composite aerogels exhibited a honeycomb-like interconnected porous structure with low density and high porosity. Kaolin acted as an inorganic reinforcing and roughness-regulating component, which promoted the formation and anchoring of an MTMS-derived siloxane/SiO₂-like hydrophobic layer on the aerogel surface. The modified aerogels showed superhydrophobicity with a water contact angle above 152° and excellent oleophilicity. The optimized SC3K0.5 aerogel delivered adsorption capacities of 13.5 g/g for pump oil and 12.5 g/g for diesel. After 10 adsorption–desorption cycles, the adsorption capacity remained above 90% of the initial value, indicating good recyclability and mechanical stability. This recyclable kaolin/cellulose aerogel provides a feasible strategy for practical oil–water separation and oily wastewater treatment. Full article

Additively manufactured cellular architectures frequently exhibit brittle failure under impact due to layer-induced stress concentrations. Through the programming of architectural and material design, specifically combining Fused Deposition Modeling (FDM) lattice topology with hyperelastic polyurea infiltration, this study achieves active control over the macroscopic transition from catastrophic structural fragmentation to stable progressive collapse. To evaluate this, auxetic and honeycomb specimens printed with ABS and glass-fiber-reinforced polyamide (PA-GF) were evaluated in unreinforced and polyurea-infiltrated states under quasi-static compression, three-point bending, and Charpy impact loading. Results show that the compressive response depends primarily on cellular topology; the pure auxetic (A-A) configuration provided the highest stiffness and energy absorption. Polyurea infiltration did not significantly alter elastic stiffness but increased post-yield stability, leading to a 96.6% elastic recovery in PA-GF A-A structures. In flexure, the base polymer governed stiffness, with ABS structures measuring 68% stiffer than PA-GF. Unreinforced ABS achieved 34% higher specific energy absorption (SEA) than PA-GF under compression, with the A-H topology maximizing SEA. Under dynamic impact, PA-GF absorbed an average of 70% more energy than ABS, and the H-A configuration recorded the highest impact resistance. The addition of polyurea shifted the failure mode from brittle fragmentation to stable elastomeric deformation, increasing absorbed impact energy by 52% for ABS and over 30% for PA-GF, preventing catastrophic structural failure. Integrating topological sequencing with elastomeric confinement provides a direct method to control energy dissipation and damage tolerance in 3D-printed cellular composites. Full article

To mitigate impact damage to airdropped supplies during landing, this study proposes a cushioning pad design method based on the C − σm (cushioning coefficient–maximum stress) curve, aiming to balance energy absorption efficiency with lightweight requirements. A medium-sized airdrop impact simulation model is established and validated via drop impact tests, and systematic dynamic impact analyses are performed on three representative cushioning materials: honeycomb paperboard, polyurethane foam, and aluminum foam. Their cushioning characteristic curves are compared, revealing that all three materials exhibit a concave C − σm profile (first decreasing, then increasing) with distinct optimal stress ranges for airdrop cushioning applications: aluminum foam for high stress (≥500 kPa), polyurethane foam for medium stress (350–450 kPa), and honeycomb paperboard for low stress (≤200 kPa). The energy absorption potential decreases with the optimal stress threshold, while cushion thickness positively correlates with the airdrop load range. In the low-stress stage, the maximum stress shows a strong functional dependence on energy density, rendering thickness effects negligible for energy absorption. Under the material fragility constraint, the C − σm curve-based graphical method can accurately determine the cushion pad’s optimal thickness and bearing area. In design Case 3, optimizing the bearing area reduced the required cushion thickness from 100.5 cm to 25.0 cm, substantially decreasing the cushion volume. The findings provide reliable material-level insights and theoretical support for impact protection design in airdrop cargo, with clear guidance on selecting cushioning materials based on their intrinsic mechanical response. Full article

Designing lightweight composite sandwich structures is challenging due to the conflicting objectives of minimizing structural weight and cost while satisfying strength and stiffness requirements. The optimization procedure becomes more complex when multiple discrete design variables and nonlinear material behavior are involved. This study presents a newly developed optimization methodology for a sandwich structure composed of Fiber Reinforced Polymer (FRP) laminated facesheets and an aluminum honeycomb core. To reduce the computational cost associated with repeated high-fidelity Finite Element (FE) analyses, a surrogate modeling strategy based on Artificial Neural Networks (ANNs) is employed to approximate the structural response. The applied dataset is generated using Monte Carlo simulation in which combinations of design variables are used as inputs, and the corresponding structural responses obtained from the analytical formulation are used as outputs for training the ANN surrogate model. The trained ANN model is integrated with a Multi-Objective Niching Memetic Particle Swarm Optimization (MO-NMPSO) algorithm to simultaneously minimize structural weight and material cost while satisfying constraints on facesheet strength, wrinkling, intra-cell buckling, deflection, core shear failure and structural thickness. The resulting Pareto-optimal solutions are validated through detailed FE simulations, demonstrating the reliability of the newly elaborated optimization framework. The results of the newly developed computationally efficient optimization procedure provide a diverse set of optimal design solutions for the investigated sandwich structure. Full article

Metamaterials with tailored structural architectures enable negative thermal expansion through geometric mechanisms that counteract constituent-level positive expansion. This study evaluates the thermomechanical performance and structural limits of polymer and hybrid NTE lattices. We systematically classify the dominant kinematic mechanisms, including bimetallic bending, rotational squares, and re-entrant honeycombs, and quantify the inherent trade-offs between effective thermal contraction, structural stiffness, and mass efficiency. The analysis demonstrates that reliance on idealized linear–elastic and rigid-lever models leads to significant predictive discrepancies when evaluating the physical response of polymeric and hybrid prototypes. We establish that these deviations are fundamentally governed by localized stress singularities at multi-material interfaces and the profound thermoviscoelastic softening of polymers as they approach the glass transition temperature ($T_g$). We conclude that accurate prediction of the cyclic lifespan and dimensional stability of these systems requires a transition to coupled multiphysics frameworks. Specifically, integrating temperature-dependent cohesive zone modeling and time–temperature superposition principles is essential for capturing interfacial delamination and thermal ratcheting in high-performance polymeric NTE metamaterials. Full article

The utilization of polyethylene terephthalate (PET) waste from single-use packaging offers potential for sustainable manufacturing. This study evaluates recycled PET (rPET) from bottles as an FDM filament by varying infill architectures (honeycomb, gyroid, grid, and triangles) and layer thicknesses (0.20, 0.25, and 0.30 mm), with commercial PETG as a benchmark. Compared with previous rPET FDM studies, which were limited to reporting mechanical strength, the novelty of this study lies in the fact that it not only reports mechanical strength performance, but also compares printing time requirements and material efficiency. Efficiency calculations are obtained by comparing the weight of the filament to the weight of the printed specimen, which then correlates with optimizing processing time and costs. Overall, rPET produced densities of 1.11–1.22 g/cm³, tensile strengths of 12.5–22.5 MPa, flexural strengths of 12.5–30 MPa, impact strengths of 0.032–0.060 J/mm², and surface roughnesses of Ra 5.2–7.1 μm, while PETG showed higher mechanical performance (tensile 30–39.5 MPa, flexural 30–50 MPa, impact 0.037–0.065 J/mm²) and comparable density (1.15–1.27 g/cm³). Within rPET, gyroid provided the best optimal performance; the gyroid (0.20 mm) variation achieved the highest impact response (0.060 J/mm²) and the lowest Ra (5.2 μm) and the gyroid (0.25 mm) variation maximized flexural strength (30 MPa) and the gyroid (0.30 mm) variation maximized tensile strength (22.5 MPa). Material utilization efficiency was consistently higher for rPET (65–68%) than for PETG (46–56%). These results provide an integrated rPET-specific assessment and practical parameter recommendations for functional 3D printing, while also aligning with SDG 12 by pro-moting resource-efficient circular-economy practices through the utilization of waste materials in additive manufacturing. Full article

Negative Poisson’s ratio materials show great potential in aerospace, automotive engineering, and military protection owing to their unique deformation behavior and superior mechanical properties. Nevertheless, current negative Poisson’s ratio honeycomb structures suffer from an inherent conflict between stiffness and energy absorption, along with poorly understood mechanical regulation mechanisms in complex three-dimensional nested configurations. To address these issues, this paper proposes a novel Cross Re-entrant Hexagon Nested Star-shaped Cell (CRNSC). Through theoretical derivation, finite element simulation, and quasi-static compression experiments, the mechanical properties and energy absorption characteristics of the structure are systematically investigated. A geometric characterization system based on length, angle, and thickness parameters is established. The results show that the cell wall thickness significantly increases the relative density, while the angle θ between the inner inclined strut and the horizontal line induces polarity reversal of the Poisson’s ratio. The outer inclined strut angle α and the inner angle θ exhibit monotonic or nonlinear regulatory effects on the equivalent Poisson’s ratio and the effective Young’s modulus, respectively. The optimal load-bearing configuration (α = 65°, θ = 35°) achieves a peak stress of 1.01 MPa, and the optimal deformation configuration (α = 55°, θ = 25°) reaches an ultimate strain of 4%. Theoretical, simulated, and experimental results are in good agreement with errors below 7%, validating the model’s effectiveness. Full article

Dual-material additive manufacturing enables the design of cellular structures with a tailored mechanical response through controlled material distribution and interfacial architecture. In this research, honeycomb structures fabricated by Fused Filament Fabrication (FFF) using dual-material TPU/PLA configurations have been systematically investigated. Particular emphasis is placed on interlocking TPU/PLA joint designs, implemented through tau-shaped and teeth-based geometries, to evaluate their role in load transfer and structural performance. An experimental–analytical model has been developed to characterize the compressive force–displacement response of dual-material honeycombs, capturing the three characteristic deformation regimes—initial stiffness, progressive collapse, and densification—while linking the effective stiffness to the underlying beam-lattice mechanics. The relative contributions of axial and bending deformation mechanisms are quantified through a comparative beam element approach, introducing dimensionless coefficients that reflect the governing deformation mode. The results reveal that the mechanical response is bending-dominated for the examined configurations. The configuration with PLA at the nodes and TPU at the struts exhibits a higher load-carrying capacity and a more stable collapse regime due to a more balanced axial–bending interaction. In contrast, alternative material distributions lead to earlier instability and reduced structural efficiency. The proposed analytical model demonstrates excellent agreement with the experimental data across all configurations. The results demonstrate that properly designed dual-material interlocks can enhance load transfer, decrease stress concentrations, and refine the overall mechanical performance of lightweight cellular structures. Full article

A lightweight and high-efficiency microwave-absorbing material was developed via an in situ solvothermal pyrolysis strategy by anchoring sphere-like Fe₃O₄ nanostructures onto bamboo-derived porous carbon (BPC). The resulting composites preserve the intrinsic anisotropic honeycomb architecture of bamboo while introducing uniformly distributed magnetic nanoparticles, enabling synergistic dielectric–magnetic loss. Electromagnetic parameters, alongside impedance matching, were successfully modulated through the optimization of precursor concentrations. Of the evaluated materials, BPC-0.9 stood out for its intense attenuation, recording an RL_min of −45.17 dB at a 1.8 mm thickness. Furthermore, a significant effective absorption bandwidth of 6.65 GHz was attained by the BPC-0.6 sample at only 2.2 mm. Several factors contribute to the boosted efficiency, starting with conductive and interfacial polarization losses paired with multiple scattering events. Furthermore, magnetic loss components, encompassing eddy current effects as well as natural and exchange resonances, play a pivotal role in optimizing the material’s response. Furthermore, radar cross-section (RCS) modeling reveals a substantial reduction of 19.9 dB·m², verifying the material’s viability for real-world stealth technologies. Our findings offer a straightforward methodology for fabricating magnetic carbon structures from biomass with adjustable dielectric responses, underscoring their potential in high-performance energy conversion and low-density microwave absorption. Full article

Symmetric corrugated hierarchical honeycombs (SCHHs) are critical lightweight load-bearing structures, featuring distinctive topological architectures and excellent mechanical performance. However, they are prone to local buckling under out-of-plane compression and shear loading, which degrades their overall load-bearing capacity. To address this limitation, this work proposes an innovative dual-optimization strategy integrating cylindrical support structure introduction and nano-silica (SiO₂) matrix modification to synergistically enhance the compressive and tribological properties of SCHHs. 3D-printed SCHHs and their reinforced variant (SCHH-AC) with embedded cylindrical supports were fabricated, and the effects of nano-SiO₂ modification (0–9 wt.%) on the compressive performance and tribological behavior of the photopolymer resin matrix were systematically investigated. Experimental results demonstrate that the SCHH-AC-7% SiO₂ configuration achieves optimal compressive performance. A critical SiO₂ concentration threshold was identified: agglomeration at 9 wt.% induces severe mechanical degradation. Tribological tests confirm that SiO₂ incorporation effectively reduces the resin matrix’s friction coefficient and wear rate, with the 7 wt.% concentration yielding the lowest wear rate. Additionally, geometric parametric analysis reveals that increasing the corrugation period number and amplitude further enhances SCHH’s compressive strength and energy absorption. This study establishes a theoretical and experimental foundation for the structural design and material modification of lightweight honeycombs, advancing their practical application in high-performance engineering fields demanding lightweight load-bearing and wear resistance. Full article

Bone tissue engineering requires biomimetic materials; however, pure polylactic acid (PLA) exhibits limited osteoinductivity and produces acidic byproducts upon degradation. To address these limitations, this study fabricated PLA scaffolds using fused-deposition modeling (FDM) with four distinct lattice structures (rectangular, triangular, gyroid, and 3D honeycomb) and incorporated hydroxyapatite (HA) at 0, 10, 20, and 30 wt% via injection molding. Mechanical properties were evaluated via compression, three-point bending, and tensile testing. The results revealed that increasing HA content significantly reduced structural strength and increased brittleness across all test modes. Specifically, specimens with 30 wt% HA exhibited a 70.8% reduction in bending strength relative to pure PLA (from 58.60 MPa to 17.07 MPa), while tensile strength decreased by 46.1% at just 10 wt% HA (from 37.54 MPa to 20.23 MPa). Although the triangular lattice achieved the highest absolute compressive load, the rectangular lattice provided a superior load-to-weight ratio and greater plastic deformation capacity before fracture. Consequently, these findings indicate that the rectangular pattern at 70% infill density combined with HA addition limited to ≤10 wt% represents the most mechanically balanced design for bone defect repair applications. Based on the mechanical characterization performed in this study, and drawing on published evidence regarding the biological properties of PLA/HA composites, these scaffolds represent a mechanically promising candidate for further evaluation in bone tissue regeneration. Biological validation through in vitro and in vivo studies is required before clinical relevance can be established. Full article