Ultrasonic fatigue testing provides an accelerated method for evaluating very-high-cycle fatigue (VHCF); however, its high test frequency induces self-heating in carbon fiber-reinforced plastic (CFRP) composites. To investigate the effect of self-heating, we conducted hydraulic fatigue tests at multiple temperatures and ultrasonic fatigue tests on quasi-isotropic CFRP laminates. In the S-N diagram, the fitting curves of the hydraulic fatigue test at each temperature intersected at approximately 109 cycles, suggesting that self-heating below 80°C has only a minor influence on final failure in the VHCF regime. However, the quantitative evaluation of cracks per layer revealed different accumulation behaviors, indicating the influence of thermal residual stress and temperature-dependent properties of the epoxy. These results show that although ultrasonic testing is effective for evaluating the fatigue life in VHCF, interpreting the damage mechanisms requires careful consideration of the thermal effects caused by self-heating.

Diamond/Cu composites can be used to achieve the efficient heat dissipation of high-power devices. Particularly, the low coefficient of thermal expansion, smooth surface, and relatively low cost of fine-grained diamond/Cu composites make them promising candidates for further research. However, high interfacial thermal resistance is difficult to be mitigated for diamond/Cu composites with a high volume fraction of fine-grained diamond particles, which severely limits their thermal conductivity. In this study, a high-temperature high-pressure infiltration process was employed to construct a three-dimensional (3D) continuous diamond network within the diamond/Cu-B composite, where the fine-grained diamond particles were interconnected by direct bonding. Microstructural characterization provided direct evidence of diamond-diamond bonding that form a primary pathway for efficient phonon transport. This continuous network shifts the heat transfer mechanism from ‘metal-matrix-dominated’ to ‘diamond-network-dominated’, thereby overcoming the thermal resistance bottleneck imposed by the high content of fine-grained diamond particles (≥80%). The composite achieved a thermal conductivity of ~ 399 W/(m·K) while maintaining excellent surface flatness (Ra ≈ 1.3 μm). The strategy of constructing a continuous diamond network to optimize thermal transport pathways provides a new paradigm for developing next-generation composites with ultra-high thermal conductivity.

This study presents the synthesis and characterization of Sr2+/Cd2+ co-doped α- MnO2 nanoparticles prepared via a simple chemical co-precipitation method for advanced energy storage applications. XRD analysis confirmed the tetragonal α- MnO2 phase with a reduced crystallite size from 15.8 nm to 7.1 nm, indicating effective dopant incorporation. TEM and SAED revealed a transition from flake-like to rod-shaped morphology, promoting efficient ion transport. XPS spectra verified the coexistence of Mn3+ and Mn4+ oxidation states and the successful substitution of Sr2+ and Cd2+ ions, which introduced lattice strain and oxygen vacancies. VSM results showed weak antiferromagnetic and superparamagnetic behaviour, associated with surface spin interactions and structural distortions. These modifications enhanced electron mobility and ionic conductivity, resulting in a specific capacitance of 614.49 F g−1 at 5 mV s−1 in 3 M KOH, outperforming single-doped MnO2 systems. The synergistic role of Sr2+ and Cd2+ ions, where Sr2+ stabilizes the structure and widens diffusion channels, while Cd2+ creates defect sites that boost charge transfer contributes to superior pseudocapacitive behaviour. The findings establish the Sr2+/Cd2+ co-doped α- MnO2 nanocomposite as a stable, high-performance electrode material suitable for next-generation supercapacitors and hybrid energy storage devices.

This study explores the mechanical behavior and quasi-static puncture failure of additively manufactured (AM) Acrylonitrile Butadiene Styrene (ABS) with varying lattice structures. Mechanical properties such as tensile strength, flexural strength, interlaminar shear strength (ILSS), and energy absorption were tested according to ASTM standards. Among the designs, the triangular lattice structure showed superior performance, with a 4.97% increase in tensile strength (26.21 MPa), a 26.91% rise in flexural strength (43.11 MPa), and a 14.57% improvement in ILSS (6.29 MPa) compared to the square lattice. Quasi-static puncture testing using a stainless-steel hemispherical indenter revealed that the triangular structure achieved the highest total energy absorption (25.08 J) and specific energy absorption (0.611 J/g). These results demonstrate that triangular ABS lattices offer improved mechanical strength and puncture resistance, making them suitable for applications in biomedical implants and advanced engineering systems.

The dispersion of carbon nanotubes (CNTs) within metal matrices presents significant challenges, including agglomeration and reduced mechanical qualities that remain unresolved, primarily due to their tendency to agglomerate caused by strong van der Waals forces. This study examines the function of nanoclay as a secondary reinforcement to mitigate these problems in aluminum (Al)-CNT composites produced using powder metallurgy. Nanoclay was chosen due to its high specific surface area and layered structure, which benefit the dispersion of CNTs. Al-CNT-nanoclay composites were fabricated using mechanical milling under controlled conditions, thereafter undergoing compaction and sintering. Various weight percentages of nanoclay (1%, 3%, and 5%) were incorporated into pure Al and Al-1 wt.% CNT composites, and the morphology of the powders, dispersion of nanoparticles, and hardness of the sintered composites were studied. The use of 1 wt.% nanoclay promoted a more homogeneous dispersion of CNTs, diminishing agglomeration. Microstructural analysis revealed that incorporating nanoclay led to a reduction in crystal size and standardization of grain structures, which resulted in an increase in hardness from 172 Vickers for pure milled aluminum to 202 Vickers for the composite with 1 wt.% CNT and 1 wt.% nanoclay. These findings suggest potential applications of Al-CNT-nanoclay composites in aerospace and automotive industries, where lightweight, high-strength materials are essential.

The development of flame-retardant resin with low viscosity and minimal curing shrinkage for the resin transfer molding (RTM) process in aviation is not yet fully mature. Thus, ammonium polyphosphate (APP) and benzoxazine (BOZ) resin were used for the synergistic modification of epoxy to enhance flame retardancy and minimize curing shrinkage in this work. The curing reaction characteristics, rheological properties, flame-retardant performance, and mechanical properties of the modified resin were investigated. The results show that neither APP nor BOZ can simultaneously improve the flame retardancy and mechanical properties of the resin, respectively. However, when 10 wt% APP and 5 wt% BOZ are employed together for synergistic modification, the modified resin (entitled 10A5B) demonstrates an optimally balanced low viscosity and minimal curing shrinkage. Thanks to the combination of the acid source formed by APP, the carbon source formed by the reaction of BOZ with EP, and the non-flammable gases, 10A5B achieves the highest limited oxygen index of 31.3% and the lowest peak heat release rate, total heat release, peak smoke release rate, and total smoke release among the modified resins. The synergistic effect of a stable, continuous, thick, and expanded char layer, along with the dilution of non-combustible gases, significantly contributes to the excellent flame retardancy of 10A5B. Moreover, its tensile strength and impact strength are enhanced by 8.2% and 3.8%, respectively, while the curing shrinkage is reduced by 13% compared to the resin modified with the same mass fraction of APP alone.

In this paper, the leading and lagging strain relationship under prestressed CFRP is analyzed. By modifying the formula of the calculation model of the debonding bearing capacity based on the adjustment coefficients related to temperature and humidity, the calculation method of the flexural bearing capacity of the prestressed CFRP reinforced concrete beam when the debonding failure occurs under the indoor environment and high temperature environment is obtained. The flexural properties of CFRP reinforced specimens are compared with those of other composite materials. The enhancement effects of different reinforcement schemes on flexural performance were discussed. The results show that the calculated value of flexural ultimate bearing capacity of prestressed CFRP reinforced concrete beams under secondary stress is slightly less than the experimental value, and the calculated value is safe. When the reinforced beam is in a hot and humid environment, the change of temperature and humidity will deteriorate the interface performance, which will affect the occurrence time of stripping failure. The higher the temperature and humidity, the greater the degree of interface damage under the same load, and the faster the stripping time of CFRP. The bolt mechanical anchoring reinforcement scheme proposed in this paper can well play the reinforcement effect of the CFRP plate. The flexural performance is sensitive to the variable parameters of the anchoring scheme. In the reinforcement scheme, better anchoring effect can be obtained by changing the anchoring position and number of bolts. The application of this method in practical reinforcement engineering is meaningful.

Indocyanine Green (ICG), a widely used near-infrared fluorescent dye, has found extensive applications in biomedical and clinical research, including imaging, hemodynamic monitoring, drug delivery, and cell labeling. Building on the superior fluorescent properties of ICG photosensitizers and the large specific surface area of HA/CMCSs, we developed a multifunctional nano-drug delivery system, HA/CMCS@1+ICG, for photothermal therapy (PTT) and drug delivery. Using a straightforward one-pot synthesis method, we achieved nanomaterials with a high drug loading capacity of 82.8%, sustained release behavior over 48 hours, and excellent photothermal conversion efficiency of 42.3%. In vitro studies demonstrated that HA/CMCS@1+ICG effectively inhibits the proliferation of non-small cell lung cancer (NSCLC) cells and induces apoptosis by modulating the expression of Survivin and Bcl-2. These results highlight the potential of HA/CMCS@1+ICG as a versatile platform for fluorescence imaging, targeted drug delivery, and PTT applications, offering a promising approach for the treatment of NSCLC.

We developed a method to evaluate the failure rate (FR) for the cylindrical part of a composite high-pressure hydrogen vessel with arbitrary dimensions, number of layers, and stacking sequences by giving the mean and standard deviation of the fiber strength development rate and the stiffness reduction rate under various damage types. The FR is the rate at which the residual strength of a vessel is below the maximum service pressure (125%NWP). Assuming a case in which the vessel is designed with the damage-tolerance design, the FR was calculated for the case of all-layer matrix cracking (assuming beginning-of-life) and fiber failure in two layers in addition to the matrix cracking (assuming the most severe damage that is tolerable during service). The observations demonstrate the importance of improving the probability of detection for non-destructive testing in ensuring the safety of damage-tolerance-designed vessels after fiber failure. The mean strength of the fibers mainly affected the mean residual strength of the composite high-pressure hydrogen vessels when the dimensions and stacking sequence remained unchanged.

The increasing need for lightweight, high strength and cost-effective materials for automotive and aerospace industries worked as the impetus for this investigation. E-glass fibers are layered with 3K-carbon fibers in proportions of 7:6 & 6:7 for fabricating hybrid fiber reinforced polymer (FRP) composites. First stage of the study involves the identification of the optimized fiber stacking pattern. Later, nanocomposites were made for further enhancement of tensile properties by infusing titanium dioxide (TiO2) nanoparticles to hybrid FRP composite ‘C2G3C3G3C2’ with optimized stacking pattern. The TiO2 nanoparticles are equally disseminated in the epoxy resin using ultrasonication with five different wt. % of 0, 1.25, 2.5, 3.75, and 5. The peak load, ultimate tensile strength (UTS), tensile modulus, and % elongation at break were examined as per ASTM D3039 tensile testing. The UTS of optimized hybrid FRP composite, carbon non-hybrid FRP composite, and nanocomposite (at 2.5 wt. % TiO2 nanoparticles) were 424.98 MPa, 429.0 MPa, and 478.51 MPa, respectively. Further, the cost of optimized hybrid FRP composite and nanocomposite (at 2.5 wt. % of TiO2 nanoparticles) is approximately 36.93% and 21.51% less than most expensive carbon non-hybrid FRP composite. The morphological analysis revealed that TiO2 added composites up to 2.5 wt. % exhibit fewer defects, indicating a better interaction between the matrix and the fibers.