【新文速递】2024年6月13日复合材料SCI期刊最新文章

今日更新：Composite Structures 5 篇，Composites Part A: Applied Science and Manufacturing 5 篇，Composites Part B: Engineering 1 篇，Composites Science and Technology 3 篇Composite StructuresGeometrically nonlinear transient analyses of rotating structures through high-fidelity modelsR. Azzara, M. Filippi, E. Carreradoi:10.1016/j.compstruct.2024.118265通过高保真模型对旋转结构进行几何非线性瞬态分析This work presents geometrically nonlinear transient analyses of various rotating blades. The structures are discretized through refined beams or multi-dimensional finite element models, which are generated using the Carrera Unified Formulation (CUF). The CUF offers a procedure to develop low- and high-fidelity one-dimensional, two-dimensional, and three-dimensional finite element models hierarchically and automatically. Various beam models were developed using different kinematics models based on Taylor or Lagrange expansion functions. Multi-dimensional models were obtained by merging beam and solid elements, exploiting the unique feature of Lagrange polynomials to have only pure displacements as unknowns. This property allows beam and solid elements to be coupled at the node level without requiring complicated mathematical formulations. By utilizing the Finite Element Method in conjunction with the CUF, the governing equations are written by including all rotation effects, namely the Coriolis term, spin-softening, and geometrical stiffening. In a total Lagrangian scenario, the Hilbert-Hughes-Taylor-α method and the iterative Newton-Raphson scheme are employed to solve the equations of motion. The proposed methodology has been applied to evaluate different blade configurations, comparing the solution obtained using linear, linearized, and nonlinear approaches. The results have been verified and validated by comparing them with existing solutions present in the literature.本研究对各种旋转叶片进行了几何非线性瞬态分析。通过使用 Carrera Unified Formulation（CUF）生成的细化梁或多维有限元模型对结构进行离散化。CUF 提供了一种程序，可分层自动开发低保真和高保真的一维、二维和三维有限元模型。使用基于泰勒或拉格朗日扩展函数的不同运动学模型开发了各种梁模型。利用拉格朗日多项式只有纯位移作为未知数的独特特征，通过合并梁和实体元素获得了多维模型。这一特性使梁和实体元素可以在节点级耦合，而无需复杂的数学公式。通过将有限元法与 CUF 结合使用，可以写出包括所有旋转效应（即科里奥利项、自旋软化和几何刚化）在内的控制方程。在总拉格朗日方案中，采用希尔伯特-休斯-泰勒-α 法和迭代牛顿-拉斐森方案来求解运动方程。所提出的方法已被用于评估不同的叶片配置，并对使用线性、线性化和非线性方法获得的解决方案进行了比较。通过与文献中的现有解决方案进行比较，对结果进行了验证和确认。A constitutive model for rate-dependency analysis of open hole woven composites under compression loadingJ.M. Rodríguez Sereno, J. Pernas-Sánchez, J.A. Artero-Guerrero, J. López Puentedoi:10.1016/j.compstruct.2024.118274用于分析压缩荷载下开孔编织复合材料速率依赖性的构成模型The mechanical performance of composite materials under impact phenomena is of interest for several industries. Although the effect of the strain rate on composites significantly affects the behaviour of these materials, most studies describe the mechanical behaviour of CFRP laminates neglecting the strain rate dependence. This work presents a new constitutive model to numerically implement the change of in-plane properties of an plain weave CFRP (AGP193) over a wide range of strain rates (up to 500 s−1). Open hole compression tests are used to validate the model under quasi-static and dynamic loading. The importance of implementing the influence of strain rate on mechanical properties is illustrated by the maximum strength plot and the stress–strain history, both of which would be underestimated without the inclusion of strain rate in the model. The strain rates at the edge of the hole greatly exceed the average values in the sample, leading to an underestimation of the apparent strength up to 100% if the strain rate effect is not taken into account.复合材料在冲击现象下的机械性能受到多个行业的关注。虽然应变率对复合材料的影响很大，但大多数研究在描述 CFRP 层压材料的机械性能时都忽略了应变率的相关性。本研究提出了一种新的构成模型，用于数值计算平织 CFRP（AGP193）在各种应变速率（最高 500 s-1）下的面内特性变化。开孔压缩试验用于验证准静态和动态加载下的模型。最大强度图和应力-应变历史记录说明了实施应变率对机械性能影响的重要性，如果不将应变率纳入模型，这两项指标都会被低估。孔边缘的应变率大大超过了样品的平均值，如果不考虑应变率的影响，表观强度会被低估达 100%。Mechanical analysis of a stitched sandwich structure and its SiO2f/SiO2 panels: Experimental and numerical investigation on compression and shear performancesDuoqi Shi, Bo Zhang, Shuangqi Lv, Changqi Liu, Zhen Cheng, Xiaoguang Yangdoi:10.1016/j.compstruct.2024.118277缝合夹层结构及其 SiO2f/SiO2 面板的力学分析：压缩和剪切性能的实验和数值研究The compression and shear performances of the stitched sandwich thermal protection structure (SSTPS) was systematically investigated through experimental and simulation methods in this study. Compression and shear testing methods were designed, and macroscopic performance data for SiO2f/SiO2 thin panels and SSTPS were successfully obtained, thereby validating the rationality of the experimental approach. By establishing mechanical experimental methods, the correlation between microscopic structural features and macroscopic mechanical performance was revealed, and mechanical modeling and analysis work was conducted. The experimental and numerical results indicate that compression and shear failure of thin panels mainly occur at the intersections of fiber bundles, exhibiting non-brittle failure. The delamination of sandwich materials or the buckling deformation of panels is identified as the primary cause of the nonlinear response in SSTPS. Elevated temperatures induce an increase in the modulus and strength of SSTPS and a decrease in toughness, correlated with the high-temperature densification of the matrix structure. Finite element simulations reveal the critical role of component and interface damage in macroscopic nonlinear mechanical responses. The research demonstrates that, the compressive and shear failure mechanisms of SiO2f/SiO2 thin panels and SSTPS were successfully elucidated through the implementation of an innovative experimental methodology.本研究通过实验和模拟方法系统地研究了缝合夹层热保护结构（SSTPS）的压缩和剪切性能。设计了压缩和剪切测试方法，并成功获得了 SiO2f/SiO2 薄板和 SSTPS 的宏观性能数据，从而验证了实验方法的合理性。通过建立力学实验方法，揭示了微观结构特征与宏观力学性能之间的相关性，并进行了力学建模和分析工作。实验和数值结果表明，薄板的压缩和剪切破坏主要发生在纤维束的交汇处，表现为非脆性破坏。夹层材料的分层或面板的屈曲变形被认为是 SSTPS 非线性响应的主要原因。温度升高会导致 SSTPS 的模量和强度增加，而韧性降低，这与基体结构的高温致密化有关。有限元模拟揭示了组件和界面损伤在宏观非线性机械响应中的关键作用。研究表明，通过实施创新的实验方法，成功地阐明了 SiO2f/SiO2 薄面板和 SSTPS 的压缩和剪切破坏机制。A peridynamic differential operator modeling approach for ceramic matrix composites microstructure with uniform or non-uniform discretizationQ.Z. Wang, Y.L. Hu, Yin Yu, Dan Wu, Z.Y. Yaodoi:10.1016/j.compstruct.2024.118282均匀或非均匀离散陶瓷基复合材料微观结构的周动态微分算子建模方法Based on the theory of peridynamic differential operator (PDDO), a novel three-dimensional (3D) peridynamic (PD) model for isotropic and orthotropic material is proposed to investigate the elastic mechanical behaviors and stress distribution of Ceramic Matrix Composites (CMC) microstructure. The non-local expressions of strain and stress tensors are derived by employing PDDO and the classical constitutive equations. The bond forces in interface region crossing two different constituent materials are obtained by converting the partial differential terms into the non-local forms. The weak form of PD equations of motion is derived by using the principle of virtual work and PDDO. The validity of this approach is verified by predicting the elastic response and stress distributions of isotropic and orthotropic materials under uniaxial tension and pure shear deformation. Finally, simulations are conducted on a CMC microstructure with fiber and matrix under periodic boundary conditions. It is demonstrated that the current approach can effectively build 3D CMC microstructure with uniform or non-uniform discretization, and accurately predict the stress fields and effective elastic properties.基于周动态微分算子（PDDO）理论，提出了一种新颖的各向同性和正交材料的三维（3D）周动态（PD）模型，用于研究陶瓷基复合材料（CMC）微结构的弹性力学行为和应力分布。通过使用 PDDO 和经典构成方程，得出了应变和应力张量的非局部表达式。通过将偏微分项转换为非局部形式，可获得两种不同成分材料交接界面区域的结合力。利用虚功原理和 PDDO 推导出了弱形式的 PD 运动方程。通过预测各向同性和各向同性材料在单轴拉伸和纯剪切变形下的弹性响应和应力分布，验证了这种方法的有效性。最后，在周期性边界条件下对带有纤维和基体的 CMC 微结构进行了模拟。结果表明，目前的方法可以有效地建立均匀或非均匀离散的三维 CMC 微结构，并准确预测应力场和有效弹性特性。Closed-form methodology for the structural analysis of stiffened composite plates with cutouts and non-uniform lay-upA. Blázquez, D. Pastorino, B. López-Romano, F. Parísdoi:10.1016/j.compstruct.2024.118284带切口和非均匀铺设的加劲复合板结构分析的闭式方法Building upon the methodology developed in prior studies, which utilized the Lekhnitskii formalism to address composite plates featuring cutouts, varying thicknesses, and different stacking sequences, the present work introduces the incorporation of stiffeners. The structural configuration comprises plates and stringers, with each stringer positioned between two plate regions and subjected to both stretching and bending loads. It is important to note that no coupling between the bending and stretching responses is accounted for; therefore, lay-ups must be symmetric, and stringers must be embedded and bisymmetric. The stringers are modeled using the Euler–Bernoulli formulation with the free torsion hypothesis, while the plates are modelled using the Kirchhoff–Love formulation. Several benchmark problems are analyzed, and the results are compared with those obtained using finite element analysis (utilizing Abaqus software), demonstrating a satisfactory agreement while also showcasing competitive computational efficiency. Thus, the present methodology provides the industry with a novel tool that enables efficient parametric analysis and facilitates the most promising configurations during the initial phases of the design to be selected by engineers.之前的研究利用 Lekhnitskii 形式主 义解决了具有切口、不同厚度和不同堆叠顺序的复合板问题，在此基础上，本研究引入了加强筋。结构配置包括板和支撑杆，每根支撑杆位于两个板区域之间，同时承受拉伸和弯曲载荷。需要注意的是，弯曲和拉伸响应之间不存在耦合；因此，层叠必须对称，纵梁必须是嵌入式和双对称的。弦杆采用带有自由扭转假设的欧拉-伯努利公式建模，而板则采用基尔霍夫-洛夫公式建模。对几个基准问题进行了分析，并将结果与使用有限元分析（利用 Abaqus 软件）获得的结果进行了比较，结果表明两者的一致性令人满意，同时也展示了极具竞争力的计算效率。因此，本方法为业界提供了一种新型工具，可实现高效的参数分析，并有助于工程师在设计的初始阶段选择最有前途的配置。Composites Part A: Applied Science and ManufacturingComputational study on the electrical conductivity of hybrid composites under mechanical deformationHyeontae An, Jinyoung Hwangdoi:10.1016/j.compositesa.2024.108317 机械变形条件下混合复合材料导电性的计算研究This study explores the hybrid composite’s electrical conductivity response under uniaxial tensile strain, wherein conductive nanowires and insulating particulate fillers are integrated within a flexible polymer matrix. We develop a Monte Carlo–based computational model and analyze the significant influence of particulate fillers on the strain response of the electrical conductivity. The particulate fillers induce both the exclusive volume and nanowire bending effects, significantly contributing to determining the hybrid composites’ electrical conductivity. The exclusive volume effect mitigates conductivity changes under external deformation, decreasing the conductivity change rate as the particulate filler content increases when the exclusive volume effect is dominant. Conversely, the nanowire bending effect boosts conductivity change under external deformation, so when it predominates over the exclusive volume effect, the conductivity change rate increases with higher particulate filler content. The insights from the study aid in designing and optimizing flexible electronic materials resilient to mechanical deformation.本研究探讨了导电纳米线和绝缘颗粒填料集成在柔性聚合物基体中的混合复合材料在单轴拉伸应变下的导电响应。我们建立了一个基于蒙特卡罗的计算模型，并分析了颗粒填料对导电率应变响应的重要影响。微粒填料会产生排他性体积效应和纳米线弯曲效应，这对混合复合材料的导电性有重要影响。排他性体积效应可减轻外部变形下的电导率变化，当排他性体积效应占主导地位时，随着颗粒填料含量的增加，电导率变化率会降低。相反，纳米线弯曲效应会促进外部形变下的电导率变化，因此当纳米线弯曲效应优于独占体积效应时，电导率变化率会随着微粒填料含量的增加而增加。这项研究的启示有助于设计和优化可承受机械变形的柔性电子材料。A comparative study of emerging material point method and FEM for forming simulation of textile reinforcementsAmir Nazemi, Abbas S. Milanidoi:10.1016/j.compositesa.2024.108284新兴材料点法和有限元法在纺织加固材料成型模拟中的比较研究For forming simulations of fabric composites, nonlinear Finite Element Method/FEM has been a long-standing tool to predict and mitigate defects such as wrinkling. However, small-time step requirements in explicit FEM codes, numerical instabilities, and large computational time are among challenges reported. This study presents an alternative fast forming simulation technique through an application of the so-called Material Point Method/MPM, which enables the use of much larger time steps along with fewer numerical instabilities. As a preliminary step towards assessment of this method, both standard 2D deformation modes and 3D hemispherical forming setups were employed, using a plain fabric weave at dry condition. The MPM results were compared to the conventional FEM simulations, as well as to the physical experiments. Notably, the MPM method showed a runtime 20 times faster than its FEM counterpart (under a comparable mesh size), yet with the same reliability in forming predictions as verified by experiments.对于织物复合材料的成型模拟，非线性有限元法/有限元一直是预测和减少起皱等缺陷的长期工具。然而，显式有限元代码中的小时间步长要求、数值不稳定性和计算时间过长等问题也是所面临的挑战之一。本研究通过应用所谓的 "材料点法/MPM"，提出了另一种快速成型模拟技术，它可以使用大得多的时间步长，同时减少数值不稳定性。作为对该方法进行评估的第一步，我们采用了标准二维变形模式和三维半球成型设置，并使用了干燥状态下的平纹织物编织。MPM 的结果与传统的有限元模拟以及物理实验进行了比较。值得注意的是，MPM 方法的运行时间比 FEM 方法快 20 倍（在网格大小相当的情况下），但成形预测的可靠性与实验验证的相同。Impact response and energy absorption mechanisms of UHMWPE fabric and composites in ballistic applications: A comprehensive reviewAshish Joshi, Ashish Mishra, Vikas Kumar Saxenadoi:10.1016/j.compositesa.2024.108314弹道应用中超高分子量聚乙烯织物和复合材料的冲击响应和能量吸收机制：全面综述Recently, UHMWPE fabric and composites have gained attraction in ballistics due to their impressive strength-to-weight ratio and impact resistance. This article provides a critical analysis of internal and external factors influencing the impact response of UHMWPE fabric and composites. Damage mechanisms in UHMWPE yarns, fabrics, and composites are explored, which reveals the influence of internal factors like fibre properties, resin characteristics, interphase properties, and composite architecture on impact resistance. Further, the influence of external factors such as projectile type, environmental conditions, and impact velocity are discussed. The review also discussed methods employed by researchers to enhance the energy-absorbing capacity of UHMWPE fabric and its composites, focusing on improving interphase characteristics and friction between woven fabric yarns. Concluding with insights into future research, the review underscores the necessity of advancing studies to augment UHMWPE fibre’s energy absorption resistance, expanding its applications in aerospace, automotive components, protective gear, and ballistic protection.近来，超高分子量聚乙烯织物和复合材料因其出色的强度重量比和抗冲击性而在弹道学领域备受青睐。本文对影响超高分子量聚乙烯织物和复合材料冲击响应的内部和外部因素进行了深入分析。文章探讨了超高分子量聚乙烯纱线、织物和复合材料的损伤机制，揭示了纤维特性、树脂特性、相间特性和复合材料结构等内部因素对抗冲击性的影响。此外，还讨论了弹丸类型、环境条件和冲击速度等外部因素的影响。综述还讨论了研究人员为提高超高分子量聚乙烯织物及其复合材料的吸能能力而采用的方法，重点是改善相间特性和织物纱线之间的摩擦力。综述最后对未来研究提出了见解，强调有必要推进研究，以增强超高分子量聚乙烯纤维的能量吸收能力，扩大其在航空航天、汽车部件、防护装备和弹道防护领域的应用。Bi-continuous interpenetrated porous composite integrating the high strength and long plateau stress stage prepared by an in situ methodEndian Liu, Yu Bai, Jiawen Li, Hai Haodoi:10.1016/j.compositesa.2024.108315 用原位法制备高强度和长高原应力阶段一体化的双连续互穿多孔复合材料In this paper, bi-continuous interpenetrated porous composites (BIPCs) were prepared with the combination of melt foaming and infiltration casting process. All BIPCs exhibited superior mechanical performance than aluminum foam (AF) and the sum of their components. Among them, 4# BIPC (with 75 struts) showed the highest specific energy absorption which is 2.70 times that of AF, and 3# BIPC (with 48 struts) presented the best improvement in terms of structural strength, while 2# BIPC (with 27 struts) exhibited the largest enhancement of energy absorption. The results indicate that the in situ interface of AF and ordered lattice structure contributes to the enhanced strength of BIPCs, while pores in AF prolongs the stress plateau stage. This research provides a novelty method to solve the trade-off between different mechanical property indicators.本文结合熔体发泡和渗透铸造工艺制备了双连续互穿多孔复合材料（BIPC）。所有 BIPC 的机械性能均优于泡沫铝（AF）及其组分的总和。其中，4# BIPC（含 75 根支柱）的比能量吸收最高，是 AF 的 2.70 倍；3# BIPC（含 48 根支柱）的结构强度改善最好；2# BIPC（含 27 根支柱）的能量吸收增强最大。研究结果表明，AF 的原位界面和有序晶格结构有助于提高 BIPC 的强度，而 AF 中的孔隙则延长了应力高原阶段。这项研究为解决不同力学性能指标之间的权衡问题提供了一种新方法。An emerging shellwich lattice material: Unlocking design freedom and enhancing mechanical propertiesMing Lei, Pan Wang, Shengyu Duan, Weibin Wen, Jun Liangdoi:10.1016/j.compositesa.2024.108316 一种新兴的贝壳晶格材料：释放设计自由度，提高机械性能This study proposes a novel sandwich shell lattice material called “shellwich”, which offsets the shell lattice to both sides to form panels and achieves the matching of porous material core layer with shell lattice panels. The shellwich lattices (P-BCC) with Schwarz Primitive (P) shell lattice panels and a body-centered cubic (BCC) truss lattice core layer are designed and fabricated. Compression experiments are carried out to explore the mechanical responses of the P-BCC experimentally and numerically. Compared with the P shell and BCC truss lattices, the P-BCC shellwich lattice demonstrates excellent mechanical properties, including widely tailorable elasticity and enhanced energy absorption. Furthermore, the effects of structural parameters on the elastic responses and energy absorption of the P-BCC are discussed. This study provides insights into the design of sandwich structures and lattice materials with high-performance and multifunctional properties, opening up new possibilities for lightweight structures, energy-absorbing systems and other engineering applications.本研究提出了一种名为 "shellwich "的新型夹层壳格材料，它将壳格向两侧偏移形成面板，实现了多孔材料芯层与壳格面板的匹配。我们设计并制造了具有施瓦茨基元（P）贝壳晶格面板和体心立方（BCC）桁架晶格核心层的贝壳晶格（P-BCC）。通过压缩实验，以实验和数值方法探讨了 P-BCC 的机械响应。与 P 壳和 BCC 桁架晶格相比，P-BCC 壳夹层晶格表现出优异的力学性能，包括可广泛调整的弹性和更强的能量吸收。此外，还讨论了结构参数对 P-BCC 弹性响应和能量吸收的影响。这项研究为设计具有高性能和多功能特性的夹层结构和晶格材料提供了启示，为轻质结构、吸能系统和其他工程应用开辟了新的可能性。Composites Part B: EngineeringBioactive hydrogels loaded with BMSC-EXOs and GDNF for synergistically spinal cord injury repairingHong Cheng, Hui Zhang, Yangnan Hu, Yusong Wang, Lei Tian, Yanru Qi, Lei Ren, Bin Zhang, Shasha Zheng, Xinyue Han, Xiaofeng Ma, Feika Bian, Huan Wang, Tingting Liu, Renjie Chaidoi:10.1016/j.compositesb.2024.111618负载 BMSC-EXOs 和 GDNF 的生物活性水凝胶可协同修复脊髓损伤Spinal cord injury (SCI) is a common lethal injury to the central nervous system (CNS), which severely affects the quality of life of SCI patients. Attempts to enhance the treatment of SCI typically tend to develop functional bioactive hydrogel scaffolds with drug encapsulation. In this work, we proposed novel RGD-functionalized bioactive hydrogel loaded with bone marrow stromal cells-derived exosomes (BMSC-EXOs) and glial cell line-derived neurotrophic factor (GDNF) to synergistically promote SCI repair. The functional hydrogel consisted of methacrylic anhydride-grafted sodium alginate and acrylated RGD, and then combined with BMSC-EXOs and GDNF by photocrosslinking to form a composite bioactive hydrogel. The hydrogel showed good drug-release properties and biocompatibility. When the bioactive hydrogel was implanted into the SCI area of the SD rats, it effectively modulated the adverse inflammatory response in the SCI area. Furthermore, the bioactive hydrogel promoted the regeneration of spinal cord neurons and axons, leading to the improvement in motor function recovery. These results indicate that the bioactive hydrogel loaded with BMSC-EXOs and GDNF has great potential as a therapeutic approach for the repair of spinal cord injuries.脊髓损伤（SCI）是中枢神经系统（CNS）常见的致命伤，严重影响脊髓损伤患者的生活质量。试图提高 SCI 治疗效果的方法通常倾向于开发具有药物封装功能的生物活性水凝胶支架。在这项工作中，我们提出了一种新型 RGD 功能化生物活性水凝胶，其中装载了骨髓基质细胞衍生的外泌体（BMSC-EXOs）和胶质细胞系衍生的神经营养因子（GDNF），可协同促进 SCI 修复。功能性水凝胶由甲基丙烯酸酐接枝海藻酸钠和丙烯酸化RGD组成，然后通过光交联与BMSC-EXOs和GDNF结合形成复合生物活性水凝胶。该水凝胶具有良好的药物释放性能和生物相容性。将该生物活性水凝胶植入 SD 大鼠的 SCI 区域后，可有效调节 SCI 区域的不良炎症反应。此外，生物活性水凝胶还促进了脊髓神经元和轴突的再生，从而改善了运动功能的恢复。这些结果表明，负载有 BMSC-EXOs 和 GDNF 的生物活性水凝胶作为脊髓损伤修复的一种治疗方法具有巨大的潜力。Composites Science and TechnologySynergistic Enhancing Effect for Electromagnetic Wave Absorption via Melamine Resin-Based Magnetic Core-Shell Microspheres/Multi-Walled Carbon NanotubesShenyang Cao, Yu’an Huang, Zhao Xu, Tienan Dong, Yihuang Su, Jiabao Lei, Siyi Zhang, Yibing Lin, Di Hao, Yichen Cao, Kaina Yang, Zusheng Hang, Runsheng Huangdoi:10.1016/j.compscitech.2024.110709 三聚氰胺树脂基磁核壳微球/多壁碳纳米管对电磁波吸收的协同增强效应Rational design of corrosion-resistant electromagnetic wave (EMW) absorbing materials with wide bandwidth, strong absorption, and low filling ratio remains a significant challenge. In this work, the melamine resin-based magnetic core-shell microspheres (MF@Fe3O4@SiO2) were synthesized via dispersion polymerization and in-situ growth method. Experimental and simulation results indicated that the content and magnetism of the magnetic shell coordinated with the MF-core could be tactfully regulated with a small amount of incorporated Ni content. Moreover, the dispersion and corrosion resistance of MF@Fe3O4 core-shell microspheres were obviously enhanced by coating SiO2. It is worth noting that after the composite of MF@Fe3O4@SiO2 with MWCNTs-20, the presence of numerous heterogeneous interfaces, the tactfully improved conductive loss, and the optimized impedance matching synergistically result in superior EMW absorption properties. When the filling amount was 30 wt.%, F9N1-S/MWCNTs-20 with a matching thickness of 1.76 mm, exhibited the maximum effective absorption bandwidth (EABmax) of 6.55 GHz, while maintaining a reflection loss (RL) of -62.94 dB at 1.53 mm. When the thickness of F9N1-S/MWCNTs-30 was increased to 3.24 mm, the RLmin at low frequencies was achieved at -67.14 dB. Besides, the simulation of radar cross section values ascertains the enormous potential of F9N1-S/MWCNTs to achieve stealth under radar detection. This study introduces a novel method for producing lightweight and efficient EMW absorbers with corrosion resistance.合理设计具有宽频带、强吸收和低填充比的抗腐蚀电磁波（EMW）吸收材料仍然是一项重大挑战。本研究通过分散聚合和原位生长法合成了三聚氰胺树脂基磁芯壳微球（MF@Fe3O4@SiO2）。实验和模拟结果表明，只要加入少量的镍，就能巧妙地调节与 MF 磁芯配合的磁壳的含量和磁性。此外，通过包覆二氧化硅，MF@Fe3O4 核壳微球的分散性和耐腐蚀性明显增强。值得注意的是，MF@Fe3O4@SiO2 与 MWCNTs-20 复合后，大量异质界面的存在、导电损耗的巧妙改善以及阻抗匹配的优化协同作用，使其具有优异的电磁波吸收特性。当填充量为 30 wt.% 时，匹配厚度为 1.76 mm 的 F9N1-S/MWCNTs-20 的最大有效吸收带宽（EABmax）为 6.55 GHz，同时在 1.53 mm 处的反射损耗（RL）保持在 -62.94 dB。当 F9N1-S/MWCNTs-30 的厚度增加到 3.24 mm 时，低频的 RLmin 达到了 -67.14 dB。此外，对雷达截面值的模拟确定了 F9N1-S/MWCNTs 在雷达探测下实现隐身的巨大潜力。本研究介绍了一种生产轻质、高效、耐腐蚀电磁波吸收器的新方法。An ultrasound-assisted resin transfer molding to improve the impregnation and dual-scale flow for carbon fiber reinforced resin compositesXinxin Xu, Kai Wei, Ming Mei, Maojun Li, Xujing Yangdoi:10.1016/j.compscitech.2024.110710 用超声波辅助树脂传递成型技术改善碳纤维增强树脂复合材料的浸渍和双尺度流动性The imbalance of the dual-scale flow, i.e., microscopic intra-bundles and macroscopic inter-bundles flow, always generates voids in resin transfer molding (RTM) of composites, substantially weakening the mechanical performance. An ultrasound-assisted strategy to improve the impregnation and to balance dual-scale flow is promising to suppress the voids, while, it has still not been explored. Here, an ultrasound-assisted RTM for carbon fiber reinforced resin composites, realized by a self-developed device, is originally proposed. The influences of ultrasound vibration on the carbon fibers, resins, wettability, and impregnation process are systematically explored. Furthermore, the dual-scale flow, affected by the ultrasound vibration, is optimized. It is identified that the ultrasound vibration effectively reduces the viscosity of the resin and increases the roughness and surface activity of the fibers, hence significantly weakening the delayed impregnation in the intra-bundles, and speeding up the impregnation velocity in the inter-bundles. The reduction of the viscosity and the contact angle synergistically lowers the modified capillary number Ca*, hence balancing the dual-scale flow, while the excessively high impregnation velocity in the inter-bundles detrimentally enlarges Ca*, leading to the imbalance of the dual-scale flow. Accordingly, a critical ultrasound energy input (4 min of ultrasound vibration at the power range of 400–600 W) is figured out to achieve an optimal Ca*, providing a promising approach to suppress the flow-induced voids in composites manufacturing by RTM.双尺度流动（即微观束内流动和宏观束间流动）的不平衡总是会在树脂传递模塑（RTM）复合材料中产生空洞，从而大大削弱其机械性能。利用超声波辅助改善浸渍并平衡双尺度流动的策略有望抑制空洞的产生，但这一方法尚未得到探索。在此，我们提出了一种超声波辅助碳纤维增强树脂复合材料的 RTM 方法，该方法是通过自主研发的设备实现的。系统地探讨了超声振动对碳纤维、树脂、润湿性和浸渍过程的影响。此外，还优化了受超声振动影响的双尺度流动。结果表明，超声振动能有效降低树脂的粘度，提高纤维的粗糙度和表面活性，从而大大减弱纤维束内的延迟浸渍，加快纤维束间的浸渍速度。粘度和接触角的降低协同降低了改良毛细管数 Ca，从而平衡了双尺度流动，而束间过高的浸渍速度则不利地扩大了 Ca，导致双尺度流动失衡。因此，我们找出了一个临界超声能量输入（在 400-600 W 功率范围内超声振动 4 分钟），以达到最佳 Ca*，从而为抑制 RTM 复合材料生产中的流动诱发空洞提供了一种可行的方法。Nano-engineered hierarchical natural fibre composites with localised cellulose nanocrystals and tailored interphase for improved mechanical propertiesShahed Ekbatani, Yushen Wang, Shanshan Huo, Dimitrios Papageorgiou, Han Zhangdoi:10.1016/j.compscitech.2024.110719 具有局部纤维素纳米晶体和定制相间物的纳米工程分层天然纤维复合材料可改善机械性能Natural fibre composites have been utilised in many applications such as automotive and buildings, thanks to their high specific properties and environmentally friendly nature. However, the incompatibility between hydrophilic natural fibres and hydrophobic polymer resins remains a longstanding issue in natural fibre composites. Inspired by nature's hierarchical structures and tailored functionalities, a nano-engineered hierarchical natural fibre composite has been developed in this study, utilising cellulose nanocrystals (CNCs) as localised nano-reinforcements at flax surfaces in a flax/bio-epoxy system. A simple and versatile spray coating technique was used to deposit CNCs on unmodified flax fibres, without using any chemical solvents. With the increased surface roughness and hence improved epoxy wetting on nano-engineered flax surfaces (3 wt.% CNC loading), mechanical properties of the hierarchical composites have been significantly improved, with a 60% increase in interlaminar shear strength, indicating an enhanced interfacial load transfer between flax and epoxy, alongside improved flexural modulus (14%) and strength (23%). This green approach without using any chemicals provides a scalable and sustainable way to develop tailored interfaces for natural fibre composites with enhanced resin wetting and mechanical properties.天然纤维复合材料具有高特定性能和环保特性，已被广泛应用于汽车和建筑等领域。然而，亲水性天然纤维与疏水性聚合物树脂之间的不相容性仍然是天然纤维复合材料的一个长期问题。受大自然分层结构和定制功能的启发，本研究开发了一种纳米工程分层天然纤维复合材料，在亚麻/生物环氧体系中利用纤维素纳米晶体（CNC）作为亚麻表面的局部纳米增强体。在不使用任何化学溶剂的情况下，采用简单、通用的喷涂技术将 CNC 沉积在未改性的亚麻纤维上。随着表面粗糙度的增加，纳米工程亚麻表面的环氧润湿性也得到了改善（3 wt.% CNC 负载），分层复合材料的机械性能得到了显著提高，层间剪切强度提高了 60%，这表明亚麻和环氧之间的界面载荷传递得到了加强，同时弯曲模量（14%）和强度（23%）也得到了提高。这种不使用任何化学品的绿色方法为开发具有增强树脂润湿性和机械性能的天然纤维复合材料定制界面提供了一种可扩展和可持续的方法。来源：复合材料力学仿真Composites FEM