Tao Liu

Carbon fiber/epoxy (CF/EP) composites are widely used in high‐performance structural applications, but insufficient interlaminar fracture toughness and limited multifunctional integration remain challenges for their broader application. In this work, boron nitride (BN) nanoparticles were incorporated into a polyacrylonitrile (PAN) solution to fabricate PAN/BN composite nanofibers, which were directly electrospun onto carbon‐fiber surfaces to construct a localized interfacial nanofiber layer. The resulting interphase combined a continuous PAN nanofiber framework with BN nanoparticles, providing additional fracture‐related energy dissipation and heterogeneous dielectric interfaces within the interlaminar region. With optimized BN loading, the modified composite exhibited enhanced Mode I interlaminar fracture toughness (G _IC ), electromagnetic shielding, and modified thermal response. The optimized 10PAN/5BN‐CF/EP composite achieved a G _IC of 706.8 ± 68.6 J m ⁻² , corresponding to a 38.1% increase compared with unmodified CF/EP. Its total electromagnetic shielding effectiveness reached 77.8 ± 5.1 dB, representing a 105.3% increase, while increased thermal diffusivity and a modified infrared thermal response were also observed. These results demonstrate that electrospun PAN/BN interfacial modification provides a localized strategy for simultaneously improving interlaminar fracture toughness and electromagnetic shielding while regulating the thermal response of CF/EP composites.

The escalating issue of electromagnetic pollution necessitates shielding materials that balance high performance with environmental sustainability. However, biomass‐derived electromagnetic interference (EMI) shielding materials are often constrained by the inherent structural fragility of agricultural waste precursors. To address this, we propose a “bio‐structure‐inherited” strategy using Macadamia Nut Shell (MNS). Through a controlled 150‐mesh grinding process, the natural thick‐walled and lumen‐rich stone cell clusters were intentionally preserved rather than completely pulverized. Upon carbonization at 800°C, these biological units evolved into robust turbostratic carbon skeletons featuring hierarchical micro‐cavities. When integrated into a polystyrene (PS) matrix via electrospinning, the resulting composite achieved an exceptional maximum EMI shielding effectiveness (SE) of 58.02 dB at a low loading of 5 wt%, significantly outperforming conventional polymer‐based biomass counterparts. Mechanistic analysis suggests that this unique architecture offers dual benefits: the thick carbonized walls facilitate efficient electron transport to enhance reflection, while the preserved lumens act as micro‐chambers to promote microwave absorption. These results indicate that retaining the natural structural integrity of recalcitrant waste provides a sustainable solution for advanced EMI shielding applications.

The warp tension applied during the preform fabrication is a critical process parameter that significantly governs the final mechanical performance of the resulting composites. In this work, an integrated experimental and finite‐element approach was employed to systematically investigate the effects of warp tension on the compressive behavior of 2.5 dimensional angle‐interlock woven composites (2.5DAWCs). The results reveal that variations in warp tension essentially alter the crimp level of the yarns and the filament‐breakage rate, thereby giving rise to distinct compressive response trends in the warp and weft directions. By incorporating tension‐induced yarn crimp and filament breakage defects into the finite‐element models, it is confirmed that the peak mechanical performance of the composites arises from a subtle balance between reduced yarn crimp and minimized filament breakage rate. Finally, based on response surface methodology, the quantitative contributions of weft density and warp tension to composite properties were established, allowing for the optimal design of processing tension parameters. The findings reported herein provide a reliable theoretical framework for the precise tailoring of high‐performance textile composites via synergistic process parameter regulation.

Three-dimensional braided composites (3DBCs) exhibit broad application prospects in the aerospace field due to their excellent mechanical properties. Considering that composites require cutting processing during real applications, this study employs a combination of experimental and finite element analysis methods to investigate the influence of edge cutting on the compressive and flexural properties of 3DBCs. In the finite element model, full-scale mesostructural models with intact and edge-cut structures were constructed based on identical unit cell size parameters. The findings reveal that the effect of edge cutting on composite mechanical properties depends on the braiding angle, primarily because the deformation resistance of braided yarns varies with different braiding angles. However, the influence mechanisms of edge cutting on braided composites with large braiding angles differ between compressive and flexural loading modes. The results of this study can provide a reference for the practical application of 3DBCs.

Phase change material microcapsules are converted into phase change materials to provide sealing protection and effectively address the leakage issue during the phase change process. However, phase change microcapsules can only passively absorb heat and store energy through temperature difference, which has a single function and cannot effectively use other energy sources. Phase change microcapsules with photothermal properties, which combine photothermal materials with phase change materials, have gradually entered people’s field of vision. They achieve direct conversion of solar energy into heat energy storage to reduce energy consumption. In this paper, the classification and basic principle of photothermal conversion materials are systematically reviewed, then the preparation methods of photothermal conversion phase change microcapsules (PCPCMs) are summarized and analyzed. Furthermore, the applications in the field of PCPCMs in the textile industry, building energy conservation, thermal management of electronic equipment, and clean energy are introduced in detail. Finally, the future research directions of PCPCMs are proposed.

Honeycomb composites show excellent properties with higher specific stiffness and strength compared with traditional composites. This work designed and manufactured a novel three‐dimensional honeycomb composite with an integrated honeycomb core structure through three‐dimensional woven fabricating technology. The influences of boundary effects, hole size and sample width of honeycomb core composites were respectively investigated through experimental and numerical methods. The results show that the rise of free wall number at the edges caused compressive properties to decrease in the weft direction but increase in warp and out of plane directions. The strength of multi free wall samples (2 main bodies) only reaching 93.6% of the few free wall samples (3 main bodies). The mechanisms of hole size affecting the compressive properties include many complicated factors such as structural scale‐law and curing defects. Finally, the decrease of compressive strength along the weft direction with the rise of width was also due to the earlier buckling failure of the honeycomb wall. The investigation of this work benefits to the design and application of the proposed honeycomb composites in many special fields.Highlights: A new three‐dimensional honeycomb core structure was designed and manufactured. The compressive behaviors of honeycomb composites were studied in detail. The number of free walls has great impacts on honeycomb composites. The mechanism of hole size effects on honeycomb composites is complicated. Fiber defects and buckling affect properties along weft direction apparently.

This work presents a new method to predict the transversal and shear properties of unidirectional composites (UD) through combining the experimental, numerical and machine learning methods. The experimental results proved the complexity and difficulty of explaining primary factors affecting the mechanical properties of UD. The representative unit cell model was then created to generate 500 virtual samples for machine learning. The results show that the back propagation neural network model (BP) is the most suitable for predicting the mechanical properties of UD, with an accuracy of 98% within a 2% error. The minimum mean square and absolute errors are 1.09E‐3 and 1.15E‐5, respectively. It is proved that the interface has significant influences on all mechanical properties of UD and shear modulus of composite in 12 directions (G_c¹²) of UD is affected by all input parameters through the optimized BP model. Due to the wide coverage of input data, the proposed BP model is universal and can be adopted to predict transversal and shear properties of UD made from different kinds of fibers.Highlights: Interface has influences on all parameters of unidirectional composites. Shear properties of unidirectional composites along 12 directions are intricated. Machine learning can predict mechanical properties of unidirectional composites. Specific samples are beneficial to improve the predicted accuracy.

Carbon fiber reinforced plastics applied in the marine industry are often exposed to conditions of seawater and alternating loads for extended periods, which can cause the complex degradation process of the composites. In this work, the coupling effects of micro-cracks and the seawater aging on the carbon fiber/epoxy resin-based plain woven composites were experimentally investigated. The micro-cracks were introduced into the composites through the three-point bending fatigue load. The results indicate that the residual stress generated by different expansions between carbon fiber and epoxy resin that reduces the interfacial properties of the composite is the primary reason for seawater aging. Besides, seawater aging causes the bending strength of the specimens with fatigue damage to decrease more seriously than that of the undamaged specimens. This is because micro-cracks increase the specific surface area of the composites in contact with seawater to provide channels for seawater diffusion. The coupling effects suggest the maintenance cycle of the composite parts should be gradually reduced if micro-cracks occur in some composites.

Three-dimensional (3D) braided composite exhibit the excellent integrity of a braided structure, which gives the composites the advantages of high-impact damage tolerance, excellent delamination resistance, and high fatigue resistance. They have been widely used in the fields of aerospace and transport. Composites are always subjected to high strain-rate loading in these application cases. Braided composites show significantly different damage evolution under varied high strain-rate loadings. A bridge which can connect the strain rate variation to the different damage evolution of composites is urgently needed for composite strength design. This research demonstrated how the strain rate variation induced the change of damage evolution and failure mode of 3D braided composite. A high-speed camera system was used to capture damage process information. A micro-scale rate-dependent finite-element model (FEM) was established to study the underlying mechanisms. The results show that the velocity gap between yarns and resin becomes more obvious at higher strain-rate loading. Damage morphology of composites under lower strain rate resulted from the higher transverse stress at the output-bar area. Higher strain-rate loading induces plastic deformation, which occurs earlier in composites. The deformation distributes more haphazardly under higher strain-rate loading. Optimizing suggestions are given to improve the impact resistance of 3D braided composites.

This paper primarily investigated the effect of fiber breakage defects on tensile properties of the unidirectional composite (UD) using the numerical simulation method. Different kinds of fiber breakage defects were firstly proved to exist in the UD according to the sub-micro computed tomography images at the microscale level. A strict random uniform distribution hypothesis was then proposed to introduce fiber breakage defects into the composite. Numerous microstructural models within random fiber breakage defects were created with the Monte Carlo method to analyze the fiber breakage defect effect on the UD. The results show that the tensile modulus of the UD was reduced by 17% when the fiber breakage defect volume fraction was only 1%, which indicates the effect of this kind of defect was very significant. The fiber volume fraction, defect volume fraction and property all have influences on the decrease of the UD caused by the fiber breakage defect. Finally, we derived a mathematical model to calculate the tensile modulus of the UD based on the numerical results. The proposed mathematical model has an application on the prediction of the axial modulus of the UD or the fiber tow containing large numbers of fiber breakage defects in the composites with complicated structure.