Composites Part A: Applied Science and Manufacturing最新文献

As polypropylene (PP) is a competitive insulating material for next generation high-voltage cable, the corresponding PP based cable semi-conductive shielding layer material needs to be developed. This paper developed an excellent material prescription and proposed an analytical method of structure-performance relationship for the application and the evaluation of PP-based cable shielding layer. First, PP/POE/CB and PP/SEBS/CB composites with different carbon black (CB) loading were prepared and their electrical and mechanical properties were compared. Through thermal analysis technique, crystalline property and thermal stability of the composites were studied in detail. And the synchrotron radiation X-ray scattering techniques were employed to analyze the distribution of carbon black in the blend semi-quantitatively. The analysis result turns out the enrichment of carbon black in POE phase and its instability at high temperature limits its application under cable operation conditions. In contrast, PP/SEBS/CB30phr is recommended for lower thermal deformation, lower PTC effect and better mechanical parameters.

Despite the known influence of chemical composition on the mechanical properties of basalt fibers, a clear understanding of this relationship is lacking. Chemical composition analysis and mechanical property tests are performed on basalt fiber samples. Test data is collected from various countries and regions to expand the dataset. An improved Physics-Informed Neural Network (PINN) approach is specifically designed to address the complexities of this relationship. By incorporating physical models like the Makishima-Mackenzie model, Rocherulle model and a symbolic regression formula, the PINN leverages established physical principles to enhance its ability to understand the underlying mechanisms governing the influence of chemical composition on mechanical properties. This focus on physical mechanisms not only improves the interpretability of the model but also empowers it to make accurate predictions, as evidenced by the high squared correlation coefficients of 0.8767 and 0.8145 between predicted and experimental values of modulus and strength, respectively.

Thermal energy harvesting, storage, conversion and utilization technologies based on phase change materials (PCMs) have received widely attention. The intelligent integration of PCMs with functional carriers or nano-additives enables the application of energy such as thermal, light, electricity and magnetism in different fields. Herein, we discuss strategies for the preparation of multifunctional composite PCMs with enhanced properties, including PCMs selection, encapsulation carrier design, thermal performance optimization, and functional integration methods. The latest progress of advanced applications of multifunctional composite PCMs in the fields of thermal management, thermal protection, medical, energy saving, and thermal camouflage is reviewed. The multifunctional design characteristics of PCMs for different applications are emphasized, as well as the relationship between the structure and thermo-physical properties of multifunctional composite PCMs. Finally, the remaining challenges of multifunctional composite PCMs and the fields that need to be broken through for advanced applications are envisioned.

Achieving a balance between strength and toughness is a vital requirement for the development of high-performance fiber-reinforced composites. Inspired by nature, this study integrates biomimetic intermittent porous carbon nanotubes (PCNT) structure into the composite for synergistically enhancing its strength and toughness. It was found that the interfacial shear strength, interfacial fracture toughness, 45FBT tensile strength, and interlaminar fracture toughness of the intermittent porous structure-coated fiber/resin composites obtained significant increases of 63.4%, 107.7%, 31.2%, and 64.3% than the baseline composites, respectively. The strengthening effect was contributed by the synergistic enhancement of the interfacial bonding areas and mechanical interlocking morphologies, as well as the significant frictional stresses induced by the morphological mismatches between adjacent gaps. The toughening mechanism was associated with the micro-crack formation, the PCNT structure rupture, and the crack deflection during the crack propagation. This work provides a promising pathway to overcome the trade-off between strength and toughness.

The percolation inception of CNT-polymer nanocomposites is studied considering the magneto-electric field effects on CNT subbands. The analytical model predicts the electrical conductivity where CNTs are modeled as slender rods with their geometric orientations as randomly distributed or aligned to transfer electrons at tunneling distance range. The tunneling effect takes into account the electron transmission between every linked pair of CNTs when evaluating electrical resistance. The subsequent CNT displacement computation and the resistance change comprise the other phase of the modeling approach. Piezoresistivity results of the analyses agree well with the experimental data when considering tunneling behavior in the percolation transition zone. The magnetic field enhances the field affected subbands and increases the electrical conductivity by enhancing the mobility of the charges. The results reveal that the efficiency of CNT network in transmitting charges is increased with higher aspect ratio CNTs that scaled the sensitivity to lower values.

The formation of woven preforms is crucial for the quality and performance of textile composites produced through the Liquid Composite Molding (LCM) process. However, the structure of the preform inevitably undergoes deformations during the weaving and forming processes, such as compression, misalignment, even wrinkle defects. Advanced experimental methods and effective numerical approaches are keys for characterizing the deformation behavior and revealing the underlying mechanisms of the woven preforms in the forming process. Initially, this review presents classical woven composite preforms. Then, advanced experimental methods for the woven preforms are provided and discussed based on the applied load. Moreover, numerical analysis approaches for preforms are summarized at different scales. Based on the above summaries, future research trends for experimental methods and numerical analysis approaches of woven preforms are proposed. These trends include the integrated multi-means characterization of deformation, improved mechanical tests, and simulation models combining machine learning algorithms and finite element methods.

Conductive hydrogels are ideal candidates for wearable strain sensors due to their intrinsic stretchability and conductivity. However, it’s still a challenge to fabricate a conductive hydrogel with a combination performance of high mechanical strength, self-adhesion, sensitivity, self-recovery capability, fatigue-resistant ability and biocompatibility. Herein, a dual-network hydrogel (TG/P-LP) composed of 2,2,6,6-tetra-methylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs) supported graphene (GN), Laponite-oxidized polydopamine (LP) and polyacrylic acid-co-poly acrylamide (P) hydrogel matrix was synthesized via a facile in-situ radical polymerization process. The optimized biocompatible TG/P-LP hydrogel exhibits a high mechanical strength, self-adhesive performance, intrinsic self-recovery capability (95.7 % in 60 min) and anti-fatigue property. The hydrogel-based strain sensor exhibits a wide strain range (0 ∼ 600 %) and a high sensitivity (GF = 12). This work designs a novel hydrogel-based sensor with excellent mechanical properties, long-term fatigue resistance, high strain sensitivity and wearability, demonstrating enormous potential in the applications of human motion detection and human–machine interaction.

Understanding stiffness degradation and developing suitable damage detection method for composite helical springs (CHSs) are important for their application and further development. In this study, a coupled plasticity-damage model for capturing stiffness degradation of CHSs with multi-braided layers (MBLs-CHS) is developed. Experimental results show that there is minor damage that only happens in the resin component of MBLs-CHS during impact. The element removal fraction in the simulation result is used to evaluate the damage severity, which is suggested to increase with impact energy (E_i) and decrease sequentially for CHSs with single, double, and triple braided layers (i.e., SCHS, DCHS, and TCHS). Specifically, damage severity of TCHS decreases by 51.3 % under 60 J impaction compared to that of SCHS. Finally, the time domain analysis method is introduced to monitor damage in real time. The amplitude intensity profiles under various Ei of CHSs have been fitted to predict the global stiffness degradation of CHSs in real time.

In this benchmark, the tensile properties of three types of organic fibres – flax, hemp and aramid − were determined using single-fibre tensile tests performed by nine research groups. Flax and hemp were chosen due to their prevalence among European fibre plants. Aramid was selected for its synthetic nature and comparable dimensional properties. Due to the morphological complexity and variability of plant fibres, the scatter in the apparent tangent modulus and strength is more pronounced for flax and hemp compared to aramid. The primary source of scatter in the tensile properties results from human factors and experimental procedures, particularly regarding the fibre selection, the measurement of the fibre cross-sectional area and of the tensile strain. The post-processing procedure also turns out to be a key factor. Finally, recommendations and guidelines for best practices are proposed to reduce the main sources of dispersion associated with the reproducibility of single fibre tensile tests.

Atmospheric plasma activation and plasma coating with 3-aminopropyltriethoxysilane (APTES) were used to investigate the effect of a modified interface on the creep behaviour of flax fibre reinforced polyoxymethylene composite. The wetting parameters and the interfacial shear strength indicate that using air-based plasma activation is superior to plasma coating with APTES when improvement of interface and mechanical properties are concerned. Hygrothermal creep tests within the linear viscoelastic region reveal that the creep resistance of air plasma treated composites is significantly enhanced, evidenced by reduced instantaneous strain and slower viscoelastic flow when compared to the untreated composites. However, creep rupture (run to failure) tests demonstrate that the air plasma treatment extends the creep lifespan only under standard conditions (50 % RH and 23 °C). Under severe conditions (85 % RH and 23 °C), plasma-treated composites exhibit a somewhat shorter lifespan, possibly because some damage induced by the plasma treatment is exacerbated at high humidity.