【新文速递】2024年3月18日复合材料SCI期刊最新文章

   

今日更新：Composite Structures 7 篇，Composites Part A: Applied Science and Manufacturing 6 篇，Composites Science and Technology 6 篇

Composite Structures

A mesoscale computational approach to predict ABD matrix of thin woven composites

Hao Jin, Ning An, Qilong Jia, Xiaofei Ma, Jinxiong Zhou

doi:10.1016/j.compstruct.2024.118031

预测薄编织复合材料 ABD 基体的中尺度计算方法

The ABD matrix is a fundamental method to characterize the overall stiffness behavior of laminated composite structures. Although classical laminate theory has been widely used, it has limitations in predicting the ABD matrix for woven composites. To address this issue, this paper presents a mesoscale homogenization approach aimed at computing the ABD matrix for thin woven composites accurately. The mesoscale representative volume element (RVE) of the woven composite is generated using TexGen and imposed with periodic boundary conditions to enforce the Kirchhoff thin plate assumption. The ABD matrix is computed by conducting six separate finite element simulations, each representing one simple in-plane or out-of-plane deformation in a specified direction. Moreover, to facilitate the implementation of the method, an open-source plugin tool was developed within ABAQUS CAE, automating the ABD matrix calculation for various types of woven composites including 2D weave, 3D weave, and multiaxial. The accuracy of the proposed method was validated through benchmark calculations against existing literature results.

ABD 矩阵是表征层状复合材料结构整体刚度行为的基本方法。尽管经典层压理论已被广泛应用，但它在预测编织复合材料的 ABD 矩阵方面存在局限性。为解决这一问题，本文提出了一种中尺度均质化方法，旨在精确计算薄编织复合材料的 ABD 矩阵。使用 TexGen 生成编织复合材料的中尺度代表体积元素 (RVE)，并施加周期性边界条件以执行基尔霍夫薄板假设。ABD 矩阵是通过进行六次单独的有限元模拟计算得出的，每次模拟都代表一个指定方向上的简单 平面内或平面外变形。此外，为便于该方法的实施，在 ABAQUS CAE 中开发了一个开源插件工具，可自动计算各种编织复合材料的 ABD 矩阵，包括二维编织、三维编织和多轴编织。通过与现有文献结果进行基准计算，验证了所建议方法的准确性。

A multifunctional three-dimensional lattice material integrating auxeticity, negative compressibility and negative thermal expansion

Yu Yao, Ye Zhou, Ling Hao Chen, Yu Jie Gu, Min. Li, Xiao He Li, Xin Zhao, Na. Xu, Jian Hai Jin, Jun Ding

doi:10.1016/j.compstruct.2024.118032

集辅助性、负压缩性和负热膨胀性于一体的多功能三维晶格材料

This manuscript presents a pioneering three-dimensional lattice structure that can simultaneously exhibit negative Poisson's ratio (NPR), negative compressibility (NC), and negative thermal expansion (NTE). The coexistence of the three negative indexes, whether in natural materials or in artificial structures, is extremely rare. The lattice unit cell integrates an auxetic egg-rack structure with a non-auxetic cage-like structure. Analytical expressions for the elastic constants of the unit cell are derived by using Euler-Bernoulli beam theory and subsequently validated through finite element simulations. The analytical results show that the lattice exhibits not only NPR, but also NC in a direction or specific areas as well as NTE in a direction, certain areas, or even throughout the entire volume when appropriately tailored geometries and constituent materials are employed. Furthermore, parametric analysis revealed that these properties can be adjusted within a broader range, encompassing negative and positive values, enabling diverse combinations. Metamaterials that possess multiple and adjustable negative properties enable the development of multifunctional devices capable of adapting to mechanical loads, hydrostatic pressures, and temperature fluctuations.

本手稿介绍了一种可同时呈现负泊松比（NPR）、负可压缩性（NC）和负热膨胀性（NTE）的开创性三维晶格结构。无论是在天然材料中还是在人工结构中，这三种负指数的共存都是极为罕见的。晶格单元单元集成了辅助性蛋架结构和非辅助性笼状结构。利用欧拉-伯努利梁理论推导出了单元格弹性常数的分析表达式，随后通过有限元模拟进行了验证。分析结果表明，当采用适当的定制几何结构和组成材料时，晶格不仅表现出 NPR，而且在某个方向或特定区域表现出 NC，以及在某个方向、某些区域甚至整个体积表现出 NTE。此外，参数分析表明，这些特性可以在更大范围内进行调整，包括负值和正值，从而实现多样化组合。具有多种可调负性能的超材料能够开发出能够适应机械负载、静水压力和温度波动的多功能设备。

Study on the mechanical properties and ballistic resistance of interface-modified fabrics with environmentally friendly shear thickening liquid

Ke Yan, Hao Wu, Runhan Li, Haoshi Sun, Difeng Zhu, Yuchen Wei, Shaobo Qi, Mengqi Yuan

doi:10.1016/j.compstruct.2024.118036

 

使用环保型剪切增稠液对界面改性织物的机械性能和防弹性能进行研究

Based on the modification of industrial solid waste and surface grafting of functional groups to prepare new ballistic composites with green shear thickening functionality, ammonia-modified silica (NH4-SA) particles were successfully prepared from industrial solid waste through APTMS surface modification, and the modified NH4-SA was used as the shear thickening dispersed phase to regulate the green shear thickening solution, and in order to better achieve the grafting loading of the particles of the dispersed phase, the aramid fabric (AF) was metal ion modified. Ballistic resistance was tested by combining a solid waste-based modified shear thickening fluid (NH4-SA@STF) with a metal ion modified AF fabric. Characterization tests confirmed that NH4-SA@STF exhibited a significant shear thickening effect due to the addition of reactive functional groups on the surface of NH4-SA. Yarn pull-out tests showed that NH4-SA@STF/Fe-AF had a 4-fold increase in pull-out force and better friction properties compared to AF fabrics. Ballistic tests demonstrated that NH4-SA@STF increased the ballistic limiting velocity (Vbl) of AF fabrics from 52 m/s to 99 m/s. Both layer impregnation modification and individual impregnation treatment of each layer showed strong ballistic performance, indicating that NH4-SA@STF/Fe-AF composites exhibited superior ballistic performance compared to AF fabrics. The doping of NH4-SA enhanced the friction between the yarns and increased the load-bearing area of the fabric, resulting in improved ballistic performance of NH4-SA@STF/Fe-AF composites. The study successfully achieved the regulation of ballistic properties in NH4-SA@STF/Fe-AF composites, providing a promising approach for the development of new ballistic materials with green shear thickening functionality.

基于工业固废改性和表面功能基团接枝制备具有绿色剪切增稠功能的新型弹道复合材料，以工业固废为原料，通过APTMS表面改性成功制备了氨改性白炭黑（NH4-SA）颗粒，并将改性后的NH4-SA作为剪切增稠分散相调控绿色剪切增稠液，为了更好地实现分散相颗粒的接枝负载，对芳纶织物（AF）进行了金属离子改性。通过将基于固体废弃物的改性剪切增稠液（NH4-SA@STF）与金属离子改性芳纶织物相结合，测试了其抗弹性能。表征测试证实，由于 NH4-SA 表面添加了活性官能团，NH4-SA@STF 具有显著的剪切增稠效果。纱线拉出测试表明，与 AF 织物相比，NH4-SA@STF/Fe-AF 的拉出力增加了 4 倍，摩擦性能也更好。弹道测试表明，NH4-SA@STF 将 AF 织物的弹道极限速度 (Vbl) 从 52 m/s 提高到 99 m/s。层浸渍改性和每层单独浸渍处理都显示出很强的弹道性能，表明 NH4-SA@STF/Fe-AF 复合材料的弹道性能优于 AF 织物。NH4-SA 的掺杂增强了纱线之间的摩擦力，增加了织物的承载面积，从而改善了 NH4-SA@STF/Fe-AF 复合材料的弹道性能。该研究成功实现了对 NH4-SA@STF/Fe-AF 复合材料弹道性能的调节，为开发具有绿色剪切增稠功能的新型弹道材料提供了一种可行的方法。

Semi-analytical approach for curved masonry pillars reinforced with FRCM

Gabriele Milani, Ernesto Grande, Tommaso Rotunno, Mario Fagone

doi:10.1016/j.compstruct.2024.118037

用 FRCM 加固弧形砌体支柱的半分析方法

The paper presents a semi-analytical approach for the study of the debonding phenomenon of Fiber Reinforced Cementitious Matrix (FRCM) systems externally applied to curved masonry pillars. One of the main features of the approach consists of considering the strengthening system composed by three separated components: external mortar layer, central fiber net and internal mortar layer. These components, assumed subjected to a longitudinal state of stress, interact one each other through tangential stresses developing at the level of zero-thickness interfaces. Regarding the latter, a tri-linear shear stress-slip relationship is assumed to account for a first elastic phase, a second phase exhibiting linear softening and a third phase with a possible non-null residual strength. Since in case of curved substrates, by equilibrium, normal stresses at the interfaces between fiber and matrix arise, modifying the peak tangential resistance and the ductility through, a classic Mohr-Coulomb criterion is introduced in the approach. Additionally, the central fiber net progressively transfers along the bond length the force applied at its loaded end by means of an elastic interface interposed between the internal mortar layer and the substrate, the latter assumed rigid and infinitely resistant. The longitudinal equilibrium equations written for the two mortar layers, suitably re-arranged considering the constitutive behavior of the layers, allow to deduce a field problem governed by six first order differential equations into six unknowns. The non-linearity is tackled by means of a recursive elastic numerical algorithm where the elastic modulus of the damaged materials is progressively dropped down, subdividing the bonded length into small portions where the material properties are assumed constant. For each element the solution of the field problem is known in closed form and the only variables to determine are the integration constants coming from the solution of the differential equation system. After a standard assemblage, all constants are derived imposing the boundary conditions at the extremes of the elements, which depend on the state of cracking of the matrix layer. The validation of the proposed approach is carried out with reference to recent experimental tests carried out by the Authors. The obtained results show the reliability of the approach to account for the influence of the curvature of the substrate on the debonding process of FRCM systems.

本文提出了一种半分析方法，用于研究外部应用于弯曲砌体支柱的纤维增强水泥基质（FRCM）系统的脱粘现象。该方法的主要特点之一是考虑到加固系统由三个分离的部分组成：外部砂浆层、中央纤维网和内部砂浆层。这些组成部分假定处于纵向应力状态，通过在零厚度界面上产生的切向应力相互影响。关于后者，假定存在三线剪应力-滑动关系，即第一弹性阶段、第二线性软化阶段和第三非零残余强度阶段。由于在弯曲基材的平衡状态下，纤维和基体之间的界面上会产生法向应力，从而改变切向阻力峰值和延展性，因此该方法中引入了经典的莫尔-库仑准则。此外，中央纤维网通过内部砂浆层和基体之间的弹性界面，沿粘结长度逐渐传递施加在其受力端上的力。考虑到两层砂浆的结构特性，对两层砂浆的纵向平衡方程进行了适当的重新排列，从而推导出一个由六个一阶微分方程控制的现场问题。非线性问题是通过递归弹性数值算法来解决的，在该算法中，受损材料的弹性模量逐渐降低，将粘结长度细分为小部分，并假定这些小部分的材料属性不变。对于每个元件，现场问题的解都是已知的封闭形式，唯一需要确定的变量是来自微分方程系统解的积分常数。在进行标准组合后，所有常数都将根据基体层的开裂状态，在各元素的极值处施加边界条件。作者参考了最近进行的实验测试，对提出的方法进行了验证。获得的结果表明，该方法可以可靠地解释基体曲率对 FRCM 系统脱粘过程的影响。

3D printed multifunctional hierarchical structured cellular silicones with ultraelasticity, extreme load-bearing capacity, shape morphing and sensing properties

Yu Su, Yaling Zhang, Enze Liao, Xiaoyan Liu, Changlin Li, Yu Liu, Chengzhen Geng, Ai Lu

doi:10.1016/j.compstruct.2024.118038

 

具有超弹性、极高承重能力、形状变形和传感特性的 3D 打印多功能分层结构蜂窝状有机硅

Multifunctional lightweight cellular silicone with adjustable properties has aroused great interests in many fields. However, it remains a challenge to facilely prepare multifunctional lightweight porous silicones with high load-bearing capacity. Herein, this work developed a 3D printing technique to prepare lightweight hierarchical structured cellular silicones with macroscale lattice structure and microscale intra-strand close-cell porosities, which was achieved by the expansion of thermally expandable microspheres (TEM) with plastic shells dispersed in formulated silicones. The obtained silicone foam with hierarchical porosity distributions shows excellent mechanical properties, including extreme load-bearing capacity (load is more than 165000 times its weight), high elasticity (negligible stress and strain loss under 80% compression), and high cycle durability (less than 4% strain loss under 1000 compression cycles). Besides, the incorporation of conductive fillers of MWCNTs endowed the foam with multifunctional piezoresistive and temperature-sensing properties. Furthermore, by printing multiple mixture inks of varying expansion ratios, shape morphing ability was endowed to the printed foam, to achieve complex curvature geometry facilely, demonstrating excellent versatility and potential applications in manufacturing flexible and conformal electronics of this method.

具有可调特性的多功能轻质蜂窝有机硅在许多领域都引起了极大的兴趣。然而，如何方便地制备具有高承载能力的多功能轻质多孔有机硅仍是一个挑战。在此，本研究开发了一种三维打印技术来制备具有宏观晶格结构和微观层内紧密孔隙的轻质分层结构蜂窝状有机硅，该技术是通过分散在配制有机硅中的带有塑料外壳的热膨胀微球（TEM）的膨胀来实现的。获得的具有分层孔隙分布的硅泡沫具有优异的机械性能，包括极高的承载能力（载荷是其重量的 165000 倍以上）、高弹性（80% 压缩下的应力和应变损失可忽略不计）和高循环耐久性（1000 次压缩循环下的应变损失小于 4%）。此外，MWCNTs 导电填料的加入还赋予了泡沫多功能压阻和温度感应特性。此外，通过印刷不同膨胀比的多种混合油墨，印刷泡沫还被赋予了形状变形能力，可轻松实现复杂曲率的几何形状，展示了该方法在制造柔性和保形电子器件方面的卓越多功能性和潜在应用。

Cross-scale modeling of microencapsulated self-healing composite with multiphase medium and their damage competition behavior

Haipeng Yin, Youtang Li, Hua Huang

doi:10.1016/j.compstruct.2024.118039

多相介质微胶囊自愈合复合材料及其损伤竞争行为的跨尺度建模

Constructing a high-fidelity cross-scale numerical model is the primary challenge in the multiscale analysis of multiphase medium composites.The Discrete Element Method is used in this study to build a three-medium multiscale numerical model. Further, the dynamic damage problem of microcapsules and the damage competition issues are investigated. The results indicate that (1) The damage evolution process, the location of maximum damage, and the final damage pattern of microcapsule embedded in the matrix and exposed to the ideal environment differed considerably. (2) The effect of microcapsule volume fraction on the mechanical strength of the matrix in self-healing composites is not linearly negatively correlated, but instead, there is a non-linear relationship, which is highly dependent on the strength ratio of the microcapsule to the matrix. (3) In self-healing composites, damage competition between the microcapsules and the matrix has a decisive influence on triggering the self-healing mechanism. (4) To obtain a better self-healing effect, the microcapsule volume fraction should not exceed 1.5 %, and the mechanical strength pre-maintenance should not be more than 95 % of the failure strength. The multiphase medium & multiscale analysis method proposed in this study also provides a new approach for visualizing the progressive dynamic damage problem in self-healing composites.

本研究采用离散元法建立了三介质多尺度数值模型。本研究采用离散元法建立了三介质多尺度数值模型，并进一步研究了微胶囊的动态损伤问题和损伤竞争问题。结果表明：(1) 微胶囊嵌入基体并暴露在理想环境中，其损伤演变过程、最大损伤位置和最终损伤模式存在很大差异。(2）在自愈合复合材料中，微胶囊体积分数对基体机械强度的影响并非线性负相关，而是存在非线性关系，这与微胶囊与基体的强度比有很大关系。(3）在自愈合复合材料中，微胶囊与基体之间的损伤竞争对触发自愈合机制具有决定性影响。(4) 为获得更好的自愈合效果，微胶囊的体积分数不应超过 1.5%，且维护前的机械强度不应超过失效强度的 95%。本研究提出的多相介质和多尺度分析方法也为自愈合复合材料的渐进动态损伤问题提供了一种新的可视化方法。

Fabrication and bending performance of ultra-low-density all-composite honeycomb sandwich shell based on stretching process

Ziqi Chu, Xiaojian Chen, Linzhi Wu, Guocai Yu, Qianqian Wu

doi:10.1016/j.compstruct.2024.118040

基于拉伸工艺的超低密度全复合材料蜂窝夹层外壳的制造和弯曲性能

A sandwich shell with an ultra-low-density honeycomb core was designed and manufactured from a carbon-fibre prepreg via a stretching process. Subsequently, the bending bearing limits of the sandwich shell corresponding to five possible failure modes (shear buckling, shear fracture, intracellular dimpling, face fracture, and core debonding) were obtained through theoretical predictions. Failure mechanism maps were generated to reflect the possibility of each failure mode intuitively. In addition, three-point bending tests were performed on specimens with different shell thicknesses to acquire as many of these typical failure modes as possible. Moreover, the competition mechanism between different failure modes was revealed. The research results provide theoretical guidance for parameter optimisation and applications in advanced engineering fields for ultra-low-density carbon-fibre honeycomb sandwich shells.

设计并通过拉伸工艺用碳纤维预浸料制造了一种带有超低密度蜂窝芯的夹层外壳。随后，通过理论预测获得了夹层外壳的弯曲承载极限，对应于五种可能的失效模式（剪切屈曲、剪切断裂、胞内凹陷、面断裂和芯材脱开）。生成的失效机理图直观地反映了每种失效模式的可能性。此外，还对不同壳厚的试样进行了三点弯曲试验，以获得尽可能多的典型失效模式。此外，还揭示了不同失效模式之间的竞争机制。研究成果为超低密度碳纤维蜂窝夹层壳的参数优化和在先进工程领域的应用提供了理论指导。

Composites Part A: Applied Science and Manufacturing

Super thermal insulation SiC aerogel with high elasticity and good adsorption performance prepared by constructing coaxial precursor

Pan He, Yuelei Pan, Mingyuan Yan, Lunlun Gong, Long Shi, Xudong Cheng,  Heping Zhang, Junchao Zhao

doi:10.1016/j.compositesa.2024.108153

 

通过构建同轴前驱体制备具有高弹性和良好吸附性能的超级隔热碳化硅气凝胶

Silicon Carbide (SiC) aerogel is a material with 3D network structure, low density, and high-temperature resistance, showing a broad application potential in various areas. It is currently challenging for SiC aerogels to balance the mechanical and high-temperature insulation properties. Here, a novel strategy was implemented for the first time, by constructing coaxial precursors. This structure can achieve in-situ Si-C binding and maximization the reaction sites to achieve fibers growth uniformly. The sintering time is reduced by over 90%. The fatigue resistance and elastic properties of the SiC aerogel were significantly improved. In addition, the uniform nanowire fiber and pore structure enable an ultra-low thermal conductivity of 0.018 W/(m K) at room temperature, 0.082 W/(m K) even at 900 °C, and superior structural stability at 1400 °C. Our strategy provides a feasible approach for the structural design of thermally insulated SiC aerogels with high elastic resilience and good adsorbability.

碳化硅（SiC）气凝胶是一种具有三维网络结构、低密度和耐高温性能的材料，在各个领域都具有广泛的应用潜力。目前，如何平衡碳化硅气凝胶的机械性能和高温绝缘性能是一项挑战。在这里，我们首次采用了一种新颖的策略，即构建同轴前驱体。这种结构可实现原位碳化硅结合，并最大限度地增加反应位点，从而实现纤维的均匀生长。烧结时间缩短了 90% 以上。碳化硅气凝胶的抗疲劳性和弹性性能得到显著改善。此外，均匀的纳米线纤维和孔隙结构使其在室温下具有 0.018 W/(m K) 的超低导热率，即使在 900 °C 时也能达到 0.082 W/(m K)，并且在 1400 °C 时具有优异的结构稳定性。我们的策略为具有高弹性和良好吸附性的隔热碳化硅气凝胶的结构设计提供了一种可行的方法。

Influence of physical ageing and fibre proximity on the local mechanical response of the Elium® thermoplastic composite matrix

Sarah F. Gayot, Nathan Klavzer, Alain Guillet, Christian Bailly, Pierre Gérard, Thomas Pardoen, Bernard Nysten

doi:10.1016/j.compositesa.2024.108141

 

物理老化和纤维距离对 Elium® 热塑性复合材料基体局部机械响应的影响

The prediction of the micromechanical response of fibre-reinforced polymer composites with numerical models relies on the assumption that the matrix behaves like a bulk sample of the same polymer. Yet, the presence of fibres likely impacts the thermochemical history and mechanical behaviour of the matrix (e.g. formation of an interphase during processing). In this work, micromechanical analysis of a thermoplastic polymer matrix is performed on glass fibre-reinforced composite samples manufactured by vacuum infusion and in-situ polymerisation. The interphase thickness and mechanical behaviour are assessed by atomic force microscopy (AFM). The mechanical properties of the matrix beyond the interphase are measured by nanoindentation and AFM in intra- and inter-tow matrix pockets, for different levels of natural physical ageing. While the distance to the nearest fibre does not significantly impact the polymer properties at a given ageing time, fibre proximity affects the rate and extent of physical ageing experienced by the polymer.

用数值模型预测纤维增强聚合物复合材料的微观机械响应依赖于一个假设，即基体的行为与相同聚合物的块状样品类似。然而，纤维的存在很可能会影响基体的热化学历史和机械性能（例如在加工过程中形成相间物）。在这项工作中，对通过真空灌注和原位聚合制造的玻璃纤维增强复合材料样品进行了热塑性聚合物基体的微机械分析。原子力显微镜（AFM）对相间厚度和机械性能进行了评估。在不同的自然物理老化程度下，通过纳米压痕法和原子力显微镜测量了簇内和簇间基体袋中相间层以外基体的机械性能。虽然在给定的老化时间内，与最近纤维的距离不会对聚合物的性能产生重大影响，但纤维距离的远近会影响聚合物物理老化的速度和程度。

Effect of heat treatment and test temperature on transverse cracking in tensile loading

Vivek Richards Pakkam Gabriel, Valeri Ivanov Petkov, Patrik Fernberg, Janis Varna

doi:10.1016/j.compositesa.2024.108149

热处理和试验温度对拉伸加载中横向开裂的影响

Accumulation of transverse cracks in carbon fiber heat resistant polymer (with bismaleimide formulation) cross-ply laminates during tensile loading at elevated temperatures and after long heat treatment is analysed. Data shows that both the iso-thermal heat treatment and testing at elevated temperatures reduce the transverse cracking resistance. A two-parameter Weibull failure stress distribution model with scale parameter degrading with heat treatment and elevated temperature is used for crack initiation analysis. The degradation is described by polynomial expansion including interaction terms. Data shows that the scale parameter dependence on the heat treatment time and the test temperature is rather linear. The same expansion parameters have been successfully used for laminates with the same constituents but with a different layup and fiber content.

分析了碳纤维耐热聚合物（双马来酰亚胺配方）横向层压板在高温拉伸加载和长时间热处理后横向裂纹的累积情况。数据显示，等温热处理和高温测试都会降低横向抗裂性。在裂纹起始分析中使用了双参数 Weibull 失效应力分布模型，该模型的尺度参数随热处理和高温而退化。衰减是通过多项式展开（包括交互项）来描述的。数据显示，标度参数与热处理时间和试验温度的关系相当线性。相同的膨胀参数已成功应用于具有相同成分但不同铺层和纤维含量的层压板。

Influence of fibre steering on the bearing performance of bolted joints in 3D printed pseudo-woven CFRP composites

Aonan Li, Haoqi Zhang, Dongmin Yang

doi:10.1016/j.compositesa.2024.108150

纤维转向对 3D 打印伪编织 CFRP 复合材料螺栓连接轴承性能的影响

Aiming to improve the bearing performance of bolted joints in carbon fibre reinforced polymer (CFRP) composites, this study investigates the impact of steered fibre paths around the hole edge within pseudo-woven (interlaced) composites that are manufactured by 3D printing. The influence of fibre steering on the crack initiation and propagation was examined through double-lap bearing tests performed on four distinct cases. Parallel to the comprehensive experimental study, digital image correlation (DIC) and X-ray computed microtomography (micro-CT) scans were performed to aid in understanding and identifying the various damage mechanisms in each specimen type. Results revealed that different patterns provided varying bearing abilities, with an employed pattern improving the initial bearing strength, initial fracture energy and ultimate fracture energy of the 3D printed pseudo-woven composite by 23.5%, 363.7% and 29.6%, respectively. Consequently, fibre steering in composites is found to be a promising method to tailor the bearing behaviour of bolted joints as required.

为了提高碳纤维增强聚合物（CFRP）复合材料螺栓连接的承载性能，本研究调查了通过三维打印技术制造的假编织（交错）复合材料孔边缘周围纤维路径转向的影响。通过在四种不同情况下进行的双圈轴承试验，研究了纤维转向对裂纹产生和扩展的影响。在进行综合实验研究的同时，还进行了数字图像相关性（DIC）和 X 射线微层析成像（micro-CT）扫描，以帮助理解和识别每种试样中的各种损坏机制。结果表明，不同的模式具有不同的承载能力，采用的模式可将三维打印伪编织复合材料的初始承载强度、初始断裂能和极限断裂能分别提高 23.5%、363.7% 和 29.6%。因此，复合材料中的纤维转向被认为是一种很有前途的方法，可根据需要调整螺栓连接的承载性能。

High-efficiency graphene/epoxy composite coatings with outstanding thermal conductive and anti-corrosion performance

Zhengqing Yang, Jian Che, Zhenzhong Zhang, Linbo Yu, Maosen Hu, Wen Sun, Wei Gao, Junzhe Fan, Lida Wang, Guichang Liu

doi:10.1016/j.compositesa.2024.108152

具有出色导热和防腐蚀性能的高效石墨烯/环氧复合涂层

Although graphene is an ideal thermal conductive and anti-corrosion filler, the thermal conductivity and corrosion resistance of graphene/polymer composite coatings are difficult to improve synergistically. Herein, graphene (rGO) and benzotriazole-loaded hollow mesoporous silica (BTA@HMS) were mixed into epoxy to simultaneously improve its thermal conductivity and anti-corrosion performance. The results show that the thermal conductivity of the prepared rGO-BTA@HMS/epoxy composite coating reaches 1.239 W/(m·K), which is improved by 596 % over pure epoxy. The corrosion protection property of the composite coating is four orders of magnitude higher than that of pure epoxy. Furthermore, BTA@HMS can significantly inhibit the accelerated corrosion of the copper metal coated by rGO/epoxy composite coatings through its self-healing function, and the charge transfer resistance for substrate corrosion is increased from 60 KΩ·cm2 to 3410 KΩ·cm2 due to the introduction of BTA@HMS. The prepared composite coatings have the potential for applications in thermal conductive and anti-corrosion coating fields.

虽然石墨烯是一种理想的导热和防腐填料，但石墨烯/聚合物复合涂层的导热性和防腐性难以协同改善。本文将石墨烯（rGO）和苯并三 唑负载中空介孔二氧化硅（BTA@HMS）混合到环氧树脂中，以同时提高其导热性和防腐性能。结果表明，制备的 rGO-BTA@HMS/epoxy 复合涂层的导热系数达到 1.239 W/(m-K)，比纯环氧树脂提高了 596%。复合涂层的防腐性能比纯环氧树脂高出四个数量级。此外，BTA@HMS 还能通过其自修复功能显著抑制 rGO/epoxy 复合涂层对金属铜的加速腐蚀，由于引入了 BTA@HMS，基底腐蚀的电荷转移阻力从 60 KΩ-cm2 增加到 3410 KΩ-cm2。制备的复合涂层有望应用于导热和防腐蚀涂层领域。

Symmetric sandwich microcellular (SSM) structure design for multifunctional carbon nanotubes/polymethylmethacrylate composites foam with broadband electromagnetic wave absorption

Danfeng Zhou, Zirui Yu, Huan Yuan, Yuxuan Zhu, Guoqiang Luo, Xueliang Jiang, Qiang Shen, Lianmeng Zhang

doi:10.1016/j.compositesa.2024.108154

具有宽带电磁波吸收功能的多功能碳纳米管/聚甲基丙烯酸甲酯复合泡沫的对称夹层微孔（SSM）结构设计

The ingenious acquisition of lightweight, thin thickness and wide absorption bandwidth electromagnetic wave absorbing (EMWA) materials remains a significant challenge, the architecture design of the absorber is critical. In this study, symmetric sandwich microcellular (SSM) structures made of polymethylmethacrylate (PMMA) and carbon nanotubes (CNTs)/PMMA are developed, and their EMWA behavior is detailed investigated. The optimal effective absorbing bandwidth reaches 3.00 GHz and optimal specific reflection loss value achieves −48.53 dB·g/cm3 over the X-band at 2.5 mm for resulting composite foam with 6 wt% of CNTs loading, showing a distinct improvement of EMWA performance comparing with normal single-layered sample. The dramatic improved performances mainly ascribe to the better impedance matching and multiple relaxation polarization behaviors derived from SSM structure. Such SSM structure effectively blocks heat conduction, resulting in a lower thermal conductivity (0.092 W/mK), which empowers the material to fulfill dual microwave-infrared stealth meanwhile, it is expected to be a EMWA absorber with the characteristics of “lightweight, multifunction and comprehensiveness”.

如何巧妙地获得重量轻、厚度薄、吸收带宽宽的电磁波吸收（EMWA）材料仍是一项重大挑战，吸收体的结构设计至关重要。本研究开发了由聚甲基丙烯酸甲酯（PMMA）和碳纳米管（CNTs）/PMMA 制成的对称三明治微孔（SSM）结构，并详细研究了它们的电磁波吸收行为。与普通单层样品相比，添加 6 wt% 碳纳米管的复合泡沫的最佳有效吸收带宽达到 3.00 GHz，最佳比反射损耗值在 2.5 mm 的 X 波段达到 -48.53 dB-g/cm3，显示出 EMWA 性能的明显改善。性能的显著提高主要归功于 SSM 结构带来的更好的阻抗匹配和多重弛豫极化行为。这种 SSM 结构可有效阻隔热传导，从而降低导热系数（0.092 W/mK），使材料在实现微波-红外双重隐身的同时，有望成为一种具有 "轻质、多功能、综合性 "特点的 EMWA 吸收体。

Composites Science and Technology

Toughening epoxy by nano-structured block copolymer to mitigate matrix microcracking of carbon fibre composites at cryogenic temperatures

Jiawei Wang, Wenkai Chang, Mohammad S. Islam, Feng Huang, Shuying Wu, L.R. Francis Rose, Jin Zhang, Chun H. Wang

doi:10.1016/j.compscitech.2024.110548

 

用纳米结构嵌段共聚物增韧环氧树脂，以缓解碳纤维复合材料在低温下的基体微裂纹问题

The incorporation of rigid nanoparticles has proven to enhance microcracking resistance in carbon fibre reinforced polymer (CFRP) composites at cryogenic temperatures, enabling CFRP tanks to store cryogenic liquid like hydrogen without requiring liners. Herein, we investigate efficacy of low-modulus soft nanoparticles in addressing the microcracking challenges inherent in CFRP at cryogenic temperatures. By incorporating a tri-block copolymer (BCP) into an epoxy, nano-structured fillers with an average diameter of approximately 100 nm are formed. Experimental results reveal that, at a 2.5 wt% loading, the BCP significantly increase the fracture energy of the nanocomposite by 392% at −196 °C while maintaining stiffness and strength. More importantly, composite laminates made with the BCP-modified nanocomposite matrix can prevent microcracking carbon fibre composites, even they contain multiple plies with the same orientation, such as [04/904]s, which are known to be highly susceptible to matrix microcracking at cryogenic temperatures. An advanced high-fidelity micromechanical modelling revealed that the observed toughening effect of nanostructured block copolymer at cryogenic temperatures is attributed to the increased fracture resistance of the nanocomposite matrix. The findings of this research demonstrate that low loading of block copolymer can effectively mitigate the initiation and propagation of matrix microcracks at ultra-cold temperatures.

事实证明，加入硬质纳米粒子可增强碳纤维增强聚合物（CFRP）复合材料在低温条件下的抗微裂性能，从而使 CFRP 储罐无需内衬即可储存氢气等低温液体。在此，我们研究了低模量软纳米粒子在解决 CFRP 在低温条件下固有的微裂纹难题方面的功效。通过在环氧树脂中加入三嵌段共聚物（BCP），形成了平均直径约为 100 纳米的纳米结构填料。实验结果表明，当添加量为 2.5 wt% 时，BCP 能显著提高纳米复合材料在 -196 °C 下的断裂能 392%，同时保持刚度和强度。更重要的是，使用 BCP 改性纳米复合材料基体制成的复合材料层压板可以防止碳纤维复合材料发生微裂纹，即使它们包含具有相同取向的多层复合材料，如 [04/904]，众所周知，这种复合材料在低温下极易发生基体微裂纹。先进的高保真微机械模型显示，纳米结构嵌段共聚物在低温条件下的增韧效果是由于纳米复合材料基体的抗断裂性提高所致。研究结果表明，嵌段共聚物的低负载可有效缓解超低温下基体微裂纹的产生和扩展。

Study on biaxial tensile failure behavior of ultra-thin-ply carbon fiber reinforced composites

Yanpeng Liu, Zhongjie Ren, Yuze Han, Mingfa Ren

doi:10.1016/j.compscitech.2024.110544

 

超薄层碳纤维增强复合材料的双轴拉伸破坏行为研究

The superior mechanical properties of ultra-thin-ply carbon fiber reinforced composites under uniaxial stress have been widely recognized. However, composite structures are often subjected to multiaxial loading in practical applications. Therefore, this study focuses on investigating the mechanical properties of ultra-thin-ply carbon fiber reinforced composites under biaxial stress conditions. Firstly, the geometric structure of a cruciform biaxial test specimen for composites is designed, and its rationality is demonstrated. Subsequently, cruciform biaxial test specimens with ply thicknesses of 24 μm and 100 μm are prepared for quasi-isotropic laminated plates, and biaxial tensile experiments with stress ratios of 0:1, 1:1, and 2:1 are conducted. This study establishes the failure envelope of ultra-thin-ply composites under biaxial tensile conditions and compare it with the experimental results of standard-ply composites. Finally, the fracture surfaces of the specimens and acoustic emission signals are analyzed to reveal the failure mechanisms of the composites under biaxial stress conditions. The results indicate that ultra-thin-ply carbon fiber reinforced composites exhibit higher interaction degree under biaxial stress, and their ability to suppress delamination is stronger.

超薄层碳纤维增强复合材料在单轴应力下的优异机械性能已得到广泛认可。然而，在实际应用中，复合材料结构往往要承受多轴载荷。因此，本研究重点研究超薄层碳纤维增强复合材料在双轴应力条件下的力学性能。首先，设计了复合材料十字形双轴试样的几何结构，并论证了其合理性。随后，为准各向同性层压板制备了层厚分别为 24 μm 和 100 μm 的十字形双轴试样，并进行了应力比为 0:1、1:1 和 2:1 的双轴拉伸实验。本研究确定了双轴拉伸条件下超薄层复合材料的破坏包络线，并将其与标准层复合材料的实验结果进行了比较。最后，通过分析试样的断裂面和声发射信号，揭示了复合材料在双轴应力条件下的失效机理。结果表明，超薄层碳纤维增强复合材料在双轴应力下表现出更高的相互作用度，其抑制分层的能力也更强。

Synergistic promotion of inter-particle and intra-particle polarizations in BST@TiO2/PVDF nanocomposites towards elevated dielectric properties

Fan Zhang, Guangheng Wang, Na Lin, Juanjuan Zhou, Shaolong Zhong, Mengxue Yuan, Bo Li, Wenying Zhou

doi:10.1016/j.compscitech.2024.110547

 

协同促进 BST@TiO2/PVDF 纳米复合材料的粒子间和粒子内极化，提高介电性能

Polymeric dielectrics with large dielectric constants (ε) and breakdown strength (Eb) coupled with low loss are highly pursued in modern electrical power systems. To synergistically bolster the ε and Eb and restrain the dielectric loss in the barium strontium titanite (BST)/poly(vinylidene fluoride, PVDF), in this research, a crystalline titanium dioxide (TiO2) shell was introduced onto the BST to generate PVDF nanocomposites with high ε and Eb but low loss. The findings show that, in comparison to pure BST/PVDF, the BST@TiO2/PVDF nanocomposites present largely enhanced ε, higher Eb and suppressed dielectric loss. The elevated ε results from the synergistic promotion of inter-particle and intra-particle polarizations in the nanocomposites. The TiO2 shell as a buffer layer availably mitigates the interface mismatch in dielectric parameters between BST and PVDF, thereby heightening the Eb. Additionally, by precisely controlling the TiO2 shell thickness, the best dielectric performances of the nanocomposites can be realized at low filler loadings. The underlying multiple polarization mechanisms are theoretically revealed by analyzing the dielectric data using the Havriliak-Negami equation. The present work provides new insight and paradigm for the design of polymeric dielectrics possessing simultaneously high ε and Eb yet low loss for applications in electrical power systems.

具有大介电常数（ε）和击穿强度（Eb）以及低损耗的聚合物电介质在现代电力系统中备受追捧。为了协同增强钛酸锶钡（BST）/聚偏二氟乙烯（PVDF）的ε和Eb并抑制其介电损耗，本研究在 BST 上引入了结晶二氧化钛（TiO2）外壳，以生成具有高ε和 Eb 但低损耗的 PVDF 纳米复合材料。研究结果表明，与纯 BST/PVDF 相比，BST@TiO2/PVDF 纳米复合材料在很大程度上增强了 ε、提高了 Eb 并抑制了介电损耗。ε升高的原因是纳米复合材料协同促进了粒子间和粒子内的极化。作为缓冲层的 TiO2 外壳可有效缓解 BST 和 PVDF 之间介电参数的界面失配，从而提高 Eb。此外，通过精确控制 TiO2 外壳的厚度，纳米复合材料可以在较低的填料负载下实现最佳的介电性能。通过使用 Havriliak-Negami 方程分析介电数据，从理论上揭示了潜在的多重极化机制。本研究为设计同时具有高ε和低损耗的聚合物电介质在电力系统中的应用提供了新的见解和范例。

Flexible, lightweight, high strength and high efficiently hierarchical Gd2O3/PE composites based on the UHMWPE fibers with self-reinforcing strategy for thermal neutron shielding

Huichao Liu, Hao Zhang, Xiaokai Yu, Zhongguo Xu, Jinze Cui, Mingbin Lai, Jiali Yu, Feng Bao, Zheng Tang, Caizhen Zhu, Jian Xu

doi:10.1016/j.compscitech.2024.110549

 

基于超高分子量聚乙烯纤维的柔性、轻质、高强度和高效分层 Gd2O3/PE 复合材料与热中子屏蔽的自增强策略

To tackle the challenge for materials in the fields such as deep space exploration with flexibility, light weight, high strength, and highly efficient neutron shielding properties, a novel organic-inorganic composites has been developed in this study. Based on ultrahigh molecular weight polyethylene (UHMWPE) fibers self-reinforcing linear low-density polyethylene (LLDPE) matrix method and hierarchical scattering and absorption strategy, a flexibly and light-weight multilayer structure has been designed with alternating gadolinium oxide (Gd2O3)/LLDPE layers and UHMWPE fiber layers by stacking hot-pressing to augment the mechanical properties and neutron shielding efficiency of the composites. Moreover, PE, including UHMWPE fibers and LLDPE matrix, and Gd2O3 has been utilized as neutron shielding element to enhance its neutron scattering and absorption capability via an abundance of hydrogen atoms and Gd element. The neutron shielding performance of the multilayer Gd2O3/UHMWPE/LLDPE composite, with a low density of ca. 1 g/cm3, has been verified by neutron shielding test and a simulation method of equivalent Gd areal density (EGdAD). As a result, an ca. 90.0% neutron shielding efficiency can be achieved with only 2 mm thickness of the composites (with 20 wt.% Gd2O3), and an EGdAD value of 0.0489 g/cm3 is required to achieve 99% shielding efficiency. Moreover, the composites have a significant improvement in the tensile strength and modulus, with an average increase of 1000% (15.86 MPa–179.95 MPa) and 1238% (230.53 MPa–2787.55 MPa) compared to the Gd2O3/LLDPE composites, respectively. The comprehensive performance of our developed multilayer Gd2O3/UHMWPE/LLDPE composites is superior to previously reported results in the literatures. Therefore, it has great application prospect in the various fields like aerospace.

为应对深空探测等领域对具有柔性、轻质、高强度和高效中子屏蔽性能的材料的挑战，本研究开发了一种新型有机-无机复合材料。基于超高分子量聚乙烯（UHMWPE）纤维自增强线性低密度聚乙烯（LLDPE）基体的方法和分层散射吸收策略，通过堆叠热压设计了一种柔性轻质多层结构，其中氧化钆（Gd2O3）/LLDPE层和超高分子量聚乙烯纤维层交替出现，从而增强了复合材料的力学性能和中子屏蔽效率。此外，聚乙烯（包括超高分子量聚乙烯纤维和低密度聚乙烯基体）和 Gd2O3 被用作中子屏蔽元素，通过丰富的氢原子和 Gd 元素增强其中子散射和吸收能力。多层 Gd2O3/UHMWPE/LLDPE 复合材料的密度低至约 1 g/cm3，其中子屏蔽性能已通过中子屏蔽试验和等效钆当量密度（EGdAD）模拟方法得到验证。结果表明，只需 2 毫米厚的复合材料（含 20 wt.% Gd2O3）就能达到约 90.0% 的中子屏蔽效率，而要达到 99% 的屏蔽效率，则需要 0.0489 g/cm3 的 EGdAD 值。此外，复合材料的抗拉强度和模量也有显著提高，与 Gd2O3/LLDPE 复合材料相比，分别平均提高了 1000% (15.86 MPa-179.95 MPa) 和 1238% (230.53 MPa-2787.55 MPa)。我们开发的多层 Gd2O3/UHMWPE/LLDPE 复合材料的综合性能优于之前文献报道的结果。因此，它在航空航天等各个领域具有广阔的应用前景。

Flexible and transparent polylactic acid/hydrophobically modified nanobagasse cellulose/tannic acid/MXene films with highly efficient ultraviolet shielding

Dacheng Li, Liangdong Ye, Hongbo Liu, Qiaoyan Wei, Xianhui Zhang, Zijian Zheng, Ziwei Li, Shaorong Lu

doi:10.1016/j.compscitech.2024.110550

 

具有高效紫外线屏蔽功能的柔韧透明聚乳酸/疏水改性纳米甘蔗渣纤维素/单宁酸/MXene 薄膜

Ultraviolet (UV) radiation is potentially harmful to human health, while traditional petroleum-based conventional UV shielding materials can damage the environment, which necessitates the development of environmentally friendly transparent UV shielding materials. Ti3C2 (MXene) nanosheets were dispersed in a polylactic acid (PLA) matrix via the synergistic effect of hydrophobically modified nanobagasse cellulose (HC-NBC) and tannic acid (TA) to prepare solution-cast transparent UV shielding PLA/HC-NBC/TA/MXene (PLA/NTM) composite films with tunable bandgaps. The bandgap and UV shielding performance of the PLA/NTM composite films were regulated by varying the MXene addition amount. The bandgap of the PLA/NTM composite film with an MXene content of 1 wt.% decreased to 2.37 eV, and the UVC, UVB, and UVA shielding ratios were 97.3, 96.9, and 90.8%, respectively. The visible light transmissibility of the PLA/NTM composite film was 41.8%, and its tensile strength increased by 58.4%. Furthermore, molecular dynamics simulations of the PLA/NTM composite system demonstrated that the hydrogen bonds between TA and HC–NBC synergistically promoted MXene dispersion in the PLA matrix, improving the UV shielding and mechanical properties of the PLA/NTM composite films. The findings of this study provide a new technical reference for the preparation of high-performance transparent UV shielding films.

紫外线（UV）辐射对人体健康有潜在危害，而传统的石油基常规紫外线屏蔽材料会破坏环境，因此有必要开发环境友好型透明紫外线屏蔽材料。通过疏水改性纳米甘蔗渣纤维素（HC-NBC）和单宁酸（TA）的协同作用，Ti3C2（MXene）纳米片被分散在聚乳酸（PLA）基体中，制备出具有可调带隙的溶液浇铸透明紫外线屏蔽聚乳酸/HC-NBC/TA/MXene（PLA/NTM）复合薄膜。通过改变 MXene 的添加量来调节聚乳酸/NTM 复合薄膜的带隙和紫外线屏蔽性能。MXene 含量为 1 wt.% 的聚乳酸/NTM 复合薄膜的带隙降至 2.37 eV，紫外线、紫外线吸收率和紫外线屏蔽率分别为 97.3%、96.9% 和 90.8%。聚乳酸/NTM 复合薄膜的可见光透过率为 41.8%，拉伸强度提高了 58.4%。此外，聚乳酸/NTM 复合体系的分子动力学模拟表明，TA 和 HC-NBC 之间的氢键协同促进了 MXene 在聚乳酸基体中的分散，从而提高了聚乳酸/NTM 复合薄膜的紫外线屏蔽性能和机械性能。该研究结果为制备高性能透明紫外线屏蔽膜提供了新的技术参考。

Microstructure dependent transverse strength criterion for UD-CFRP composites via computational micromechanics and machine learning

Yushu Li, Huasong Qin, Liyong Jia, Tong-Earn Tay, Vincent Beng Chye Tan, Yilun Liu

doi:10.1016/j.compscitech.2024.110551

 

通过计算微观力学和机器学习获得 UD-CFRP 复合材料横向强度的微观结构相关性准则

The transverse strength of unidirectional carbon fiber reinforced polymer (UD-CFRP) composites is a high dimensional and nonlinear function of microstructure due to the wide scatter in mechanical properties and complex failure mechanisms, which is a challenging task to develop a general microstructure dependent strength criterion (MDSC) in theory or computation. Volume fraction and distribution of fibers are among the crucial influencing factors. A computational micromechanics and machine learning (ML) combined method is employed to uncover the transverse mechanical response of UD-CFRP composites. High-throughput finite element analyses (FEA) are performed to obtain the transverse behaviors of composites with varying fiber distribution and volume fraction under different loading states. They showed that fiber distribution has different effects on strengths in different failure modes, while the failure modes are closely related to loading states and fiber volume fractions. An ML model is then trained to characterize the relations between composite microstructure and composite strength. Then, the transverse strengths of 1000 new microstructures are predicted, which shows good agreement with FEA results, so that the MDSC of UD-CFRP is constructed by fully accounting for the influence of fiber distribution. Reliability of the method is verified by considering composites with various fiber volume fractions.

单向碳纤维增强聚合物（UD-CFRP）复合材料的横向强度是微观结构的高维非线性函数，这是因为其机械性能和复杂的失效机理非常分散，要在理论上或计算上建立一个通用的微观结构相关强度准则（MDSC）是一项具有挑战性的任务。纤维的体积分数和分布是关键的影响因素。本研究采用计算微观力学和机器学习（ML）相结合的方法来揭示 UD-CFRP 复合材料的横向力学响应。高通量有限元分析（FEA）获得了不同纤维分布和体积分数的复合材料在不同加载状态下的横向行为。结果表明，纤维分布对不同失效模式下的强度有不同影响，而失效模式与加载状态和纤维体积分数密切相关。然后训练了一个 ML 模型来描述复合材料微观结构与复合材料强度之间的关系。然后，预测了 1000 种新微结构的横向强度，结果与有限元分析结果吻合，从而通过充分考虑纤维分布的影响构建了 UD-CFRP 的 MDSC。通过考虑不同纤维体积分数的复合材料，验证了该方法的可靠性。