Composite StructuresThe quasi-static responses and variable mechanical properties of a novel 3D composite auxetic tubular structure connected by the thin-walled tubeLu Huan, Wang Xiaopeng, Chen Tianningdoi:10.1016/j.compstruct.2023.117573由薄壁管连接的新型三维复合辅助管状结构的准静态响应和可变力学性能In this paper, a novel 3D composite auxetic tubular structure (3D CATS) connected by a thin-walled (TW) circular tube was proposed, and two sets of parameters h1, h2, and β, n were introduced to construct structural families with various geometries and mechanical properties. The mechanical responses of the 3D CATS were preliminarily explored through the quasi-static experiment. The good agreement between the experimental results and the finite element (FE) simulation verified the accuracy of the FE model. Subsequently, the coupling mechanism between the tube and auxetic units was revealed by analyzing the deformation modes and force responses. The results indicated that the deformation of auxetic units caused more plastic hinges in the tube to enhance the contact force seriously. Then, the 3D CATS was proved to exhibit better specific energy absorption (SEA) compared with other auxetic structures. Furthermore, the influence of h1, h2, and β, n on the responses was also discussed. The results showed that h1, h2 can change the compression displacement points and forces, while β, n can adjust the stiffness and forces. The results can provide an important reference for the design and study of variable mechanical properties for innovative 3D auxetic structures with enhanced performance.本文提出了一种由薄壁（TW）圆管连接的新型三维复合辅助管状结构（3D CATS），并提出了两组参数 h1, h2 和 β、n 两组参数，构建了具有不同几何形状和力学性能的结构族。通过准静态实验初步探讨了三维 CATS 的力学响应。实验结果与有限元（FE）模拟之间的良好一致性验证了 FE 模型的准确性。随后，通过分析变形模式和力响应，揭示了管子和辅助单元之间的耦合机制。结果表明，辅助单元的变形在管子中造成了更多的塑性铰链，从而严重增强了接触力。与其他辅助结构相比，三维 CATS 被证明具有更好的比能量吸收（SEA）性能。此外，h 1, h2、β、n 对响应的影响。结果表明，h1, h2 可以改变压缩位移点和力，而 β、n 则可以调整刚度和力。这些结果可为设计和研究具有更高性能的创新三维辅助结构的可变力学性能提供重要参考。Composites Part A: Applied Science and ManufacturingON THE EQUIVALENT FLEXURAL AND SHEAR MODULI OF LAMINATED BEAMS: DEFINITION AND DETERMINATION BY BENDING TESTSMujika Faustino, Olave Mireia, Asunción Cantera M., Garitaonaindia Ugutz, Isasa Miren, Arrese Ainhoadoi:10.1016/j.compositesa.2023.107802层压梁的等效弯曲和剪切模量：定义和通过弯曲试验确定Equivalent flexural and shear moduli of laminated beams of rectangular cross-section made of orthotropic layers are defined by an analytical approach. Equivalent flexural and shear modulus are defined as those that would correspond to a homogenous beam. In order to check the suitability of the moduli defined, three-point bending tests varying the span are carried out in a sandwich material and in hybrid laminates. In the case of the sandwich material, it is shown that a three-point bending test could be considered a shear test from the stiffness point of view. In the case of hybrid materials, virtual tests are carried out by the Finite Element Method. The agreement between equivalent moduli obtained from the analytical approach and the bending tests has been checked, being quite good in all cases. Finally, the effect of dimension uncertainty in three-point bending tests is analyzed by a Monte Carlo simulation.通过分析方法定义了由正交各向同性层组成的矩形截面层压梁的等效弯曲模量和剪切模量。等效弯曲模量和剪切模量被定义为与同质梁相对应的模量。为了检查所定义的模量是否合适，对夹层材料和混合层板进行了跨度变化的三点弯曲试验。就夹层材料而言，试验表明，从刚度角度看，三点弯曲试验可视为剪切试验。对于混合材料，采用有限元法进行了虚拟试验。根据分析方法获得的等效模量与弯曲试验之间的一致性得到了检验，在所有情况下都相当不错。最后，通过蒙特卡罗模拟分析了三点弯曲试验中尺寸不确定性的影响。Near-perfect turning of robot-based 3D printing continuous carbon fiber reinforced nylon composites based on fiber-scale internal stress characterizationSun Henglun, Li Dongsheng, Qu You, Zhi Quan, Tian Xiaoyong, Li Dichen, Zhu Weijundoi:10.1016/j.compositesa.2023.107805基于纤维尺度内应力表征的机器人三维打印连续碳纤维增强尼龙复合材料的近乎完美车削Mechanical metamaterials based on continuous fiber reinforced composites exhibit excellent mechanical properties. Continuous fiber 3D printing is counted as an ideal manufacturing approach for mechanical metamaterials. Currently, most metamaterial lattice structures are printed at centimeter-scale. The key to printing high-precision composite lattice structures below centimeter-scale is to achieve near-perfect turning of composite filament with the smallest possible radius, and continuous fiber maintains superior printing precision. Therefore, a fiber near-perfect turning placement model was established and the near-perfect turning radius ra was assessed by measuring the fiber-scale internal stress required in the model. The precision evaluations show that the near-perfect turning radius calculated by the model is in good agreement with the experimental value, proving the model’s validity. In the case of the Robot-based printing platform and Nylon-carbon fiber composites, the near-perfect turning radius is 2.0mm. This study establishes a solid process foundation for metamaterial manufacturing below the centimeter scale.基于连续纤维增强复合材料的机械超材料具有优异的机械性能。连续纤维三维打印被认为是机械超材料的理想制造方法。目前，大多数超材料晶格结构都是以厘米为单位打印的。要打印出厘米级以下的高精度复合材料晶格结构，关键在于以尽可能小的半径实现复合材料丝的近乎完美的转弯，而连续纤维可保持卓越的打印精度。因此，我们建立了纤维近乎完美转弯放置模型，并计算了近乎完美转弯半径 ra 是通过测量模型所需的纤维尺度内应力来评估的。精度评估结果表明，模型计算出的近乎完美的转弯半径与实验值十分吻合，证明了模型的有效性。就基于机器人的打印平台和尼龙-碳纤维复合材料而言，近乎完美的转弯半径为 2.0 毫米。这项研究为厘米级以下超材料制造奠定了坚实的工艺基础。Exploring Electro-Thermal Conversion in Phase Change Materials: A ReviewJia Zhaoying, Hu Caishuo, Zhang Yuang, Zhang Shufen, Tang Bingtaodoi:10.1016/j.compositesa.2023.107809探索相变材料中的电热转换：综述Phase change materials (PCMs) are recognized as an effective means of thermal energy storage with extensive use across various scenarios. Despite their utility, the inherent low conductivity of these materials significantly hampers thermal energy conversion and storage without the aid of a temperature differential. Solutions to this challenge have involved compounding PCMs with different energy conversion media to facilitate interconversion between multiple energy sources and thermal energy. Owing to the active and stable characteristics of electrical energy, composites of electrical energy with PCMs effectively imbue the resulting materials with dynamic electrothermal conversion and thermal energy storage capacities. This review conducts an in-depth analysis of the mechanisms underlying material conductivity, thermal conductivity, and electrothermal conversion. It systematically summarizes methods of constructing different conductive matrices. We also discuss the applications of these materials in electronic devices, smart fabric and other fields before summarizing the current challenges and potential future directions in electrothermal conversion.相变材料（PCM）被公认为是一种有效的热能储存手段，在各种应用场景中都得到了广泛应用。尽管这些材料非常有用，但其固有的低传导性在没有温差的帮助下极大地阻碍了热能的转换和储存。应对这一挑战的解决方案包括将 PCM 与不同的能量转换介质复合，以促进多种能源与热能之间的相互转换。由于电能具有活跃和稳定的特性，电能与 PCM 的复合材料可有效提高材料的动态电热转换和热能存储能力。本综述深入分析了材料导电性、导热性和电热转换的内在机制。它系统地总结了构建不同导电基质的方法。我们还讨论了这些材料在电子设备、智能织物和其他领域的应用，然后总结了电热转换领域当前面临的挑战和未来可能的发展方向。Composites Part B: EngineeringStudy on the in situ strengthening and toughening mechanism of H13 tool steel/WC-12Co composite using laser-based directed energy depositionXie Jichang, Raoelison Rija Nirina, Kang Nan, Mazeran Pierre-Emmanuel, Rachik Mohameddoi:10.1016/j.compositesb.2023.111011利用激光定向能沉积技术研究 H13 工具钢/WC-12Co 复合材料的原位强化和增韧机理To overcome the unworkability of hot work molds in conventional manufacturing, laser additive manufacturing (AM) is widely adopted to print molds/dies with complex internal structures. However, in the AM process, some hot work steels easily crack (e.g., H11 and H13 tool steel) or exhibit dissatisfactory wear resistance (e.g., MS1 maraging steel). To tackle this issue, toughened functionally graded metal matrix/ceramic composite materials can be fabricated on existing molds by laser directed energy deposition (L-DED). Contrary to previous studies that clad Co on WC to avoid the decomposition of ceramic, in this work, we innovatively utilized a type of WC-12Co powder with a substructure to accelerate its decomposition and improve the toughness of composites. It was found that the unmelted tens-micrometer-magnitude WC-12Co powder and in situ synthesized nano WC coexist in the laser-deposited H13 steel/WC-12Co composites to act as the reinforcement phase. Particularly, all the brittle phases (WC and FexWxC) are wrapped by soft γ phases, alleviating the coefficient of thermal expansion (CET) mismatch between materials and the residual stress generated by laser AM. Consequently, defect-free deposits with varied WC contents are manufactured by L-DED and exhibit high hardness and superior wear resistance at both room and elevated temperatures due to the second phase and grain refinement strengthening mechanisms. These findings provide a disparate metal matrix composite design route for laser additive manufacturing to improve the toughness of metal matrix/ceramic composite materials and obtain exceptional performance.为了克服热作模具在传统制造中的不可操作性，激光增材制造（AM）被广泛用于打印具有复杂内部结构的模具。然而，在 AM 工艺中，一些热作钢容易开裂（如 H11 和 H13 工具钢）或表现出令人不满意的耐磨性（如 MS1 马氏体时效钢）。为解决这一问题，可通过激光定向能沉积（L-DED）技术在现有模具上制造增韧的功能分级金属基体/陶瓷复合材料。与以往在 WC 上包覆 Co 以避免陶瓷分解的研究不同，在这项工作中，我们创新性地使用了一种具有亚结构的 WC-12Co 粉末，以加速其分解并提高复合材料的韧性。研究发现，在激光沉积的 H13 钢/WC-12Co 复合材料中，未熔化的数十微米量级的 WC-12Co 粉末和原位合成的纳米 WC 共存，共同作为增强相。特别是，所有脆性相（WC 和 FexWxC）都被软性 γ 相包裹，从而缓解了材料之间的热膨胀系数（CET）不匹配和激光 AM 产生的残余应力。因此，通过 L-DED 制造出了不同 WC 含量的无缺陷沉积物，由于第二相和晶粒细化强化机制的作用，这些沉积物在室温和高温下都表现出了高硬度和优异的耐磨性。这些发现为激光增材制造提供了一种不同的金属基复合材料设计途径，可提高金属基/陶瓷复合材料的韧性并获得优异的性能。A lacrimal duct drug delivery system based on photo-induced hydrogel for dry eye and allergic conjunctivitis therapyLin Tong, Wang Wushuang, Chen Ting, Bao Bingkun, Liu Tuan, Zhao Han, Feng Changming, Lin Qiuning, Zhu Linyong, Gong Landoi:10.1016/j.compositesb.2023.111014基于光诱导水凝胶的泪道给药系统，用于干眼症和过敏性结膜炎治疗To design an ocular drug delivery system is challenging due to the limited space of the ocular surface and high sensitivity of the cornea. Here, we developed a lacrimal duct drug delivery system, which was non-invasive and could cause no foreign body sensation. Based on hydrogels, our drug-loaded lacrimal plugs had ideal and adjustable properties of mechanical characteristics, swelling ratio and degradation rates. They also showed better biocompatibility and the feasibility of loading various drugs to treat different ocular diseases, compared to the commonly-used plug products. Our drug-loaded lacrimal plugs exhibited sustained and stable drug releasing profiles both in vitro and in vivo for up to three months. To test the therapeutic effect, FK506 loaded plugs and cyclosporine A loaded plugs were used to treat the rat allergic conjunctivitis model and rabbit dry eye model, respectively, which both demonstrated satisfactory long-term efficacy. This study illustrated a lacrimal plug drug delivery system with the potential application in the long-term treatments of a variety of ocular surface diseases.由于眼表空间有限且角膜敏感度高，设计眼部给药系统具有挑战性。在此，我们开发了一种非侵入性、无异物感的泪道给药系统。在水凝胶的基础上，我们的载药泪道塞具有理想的、可调节的机械特性、膨胀率和降解率。与常用的泪道塞产品相比，这种泪道塞还具有更好的生物相容性，可以装载多种药物治疗不同的眼部疾病。我们的载药泪腺塞在体外和体内均表现出持续稳定的药物释放特性，最长可达三个月。为了测试其治疗效果，我们分别用载入 FK506 的泪道塞和载入环孢素 A 的泪道塞治疗大鼠过敏性结膜炎模型和兔子干眼症模型，结果均显示出令人满意的长期疗效。这项研究说明了泪道塞给药系统在长期治疗各种眼表疾病方面的潜在应用。A facile and scalable approach to tear-and-use polyethylene (PE) tape with adjustable hydrophobicity for water transferringHuang Yanhao, Chen Libo, Zhang Ruiyan, Liu Lei, Liu Zhengying, Yang Wei, Wang Feng, Yang Mingbodoi:10.1016/j.compositesb.2023.111017可调节疏水性的聚乙烯（PE）撕裂使用胶带的简便和可扩展方法，用于输水Despite the refined microstructures for liquid manipulation materials is hard to be readily and massively fabricate, the damage and abrasion during storage and transportation is still a main factor limiting its service life. Herein, a facile, scalable, and eco-friendly approach to superhydrophobic polyethylene (PE) tape via constructing polypropylene (PP)-PE-PP sandwiched structures with multi-melt multi-injection molding was reported. The PE tape can be long-term protected by PP layer before use. By peeling the protective PP layers from the PE tape, the hydrophobicity can be instantly endowed to the peeled PE surface, which should give credit is the failure of the interphase layer between PE and PP, followed by in-situ formation of multi-tier microstructures of the peeled PE surface during the peeling process. The hydrophobic performance can be regulated up to 154.0 ± 8.99° by optimizing PE chain structure. Moreover, by simply tunning the peeling temperature from −198 °C to 110 °C, the PE tunable water contact angle (WCA) ranges from 133.6 ± 4.39° to utmost 156.3 ± 3.57°, owing to the transformation of hierarchical multi-tier surface topography around the transition temperature (E P). Ultimately, the as-prepared hydrophobic PE tapes were successfully utilized for loss-free manipulation and transferring of the water droplet, which provides a significant prospect of eco-friendly and continuous production for durable hydrophobic materials.尽管用于液体操作材料的精细微结构难以轻易大规模制造，但储运过程中的损坏和磨损仍是限制其使用寿命的主要因素。本文报告了一种简便、可扩展且环保的超疏水聚乙烯（PE）胶带制造方法，该方法通过多熔体多次注塑成型构建聚丙烯（PP）-PE-PP 夹层结构。聚乙烯胶带在使用前可长期受到聚丙烯层的保护。剥离聚乙烯胶带上的聚丙烯保护层后，剥离后的聚乙烯表面可立即具有疏水性，这应归功于聚乙烯与聚丙烯之间的相间层失效，以及剥离过程中剥离后的聚乙烯表面在原位形成的多层微结构。通过优化聚乙烯链结构，可将疏水性能调节至 154.0 ± 8.99°。此外，只需将去皮温度从 -198 °C 调至 110 °C，聚乙烯的可调水接触角（WCA）就可从 133.6 ± 4.39° 调至最大 156.3 ± 3.57°，这是因为在过渡温度（E P).最终，制备的疏水性聚乙烯胶带成功地用于无损操纵和转移水滴，这为生态友好型耐用疏水材料的连续生产提供了重要的前景。Composites Science and TechnologyMultiscale Fast Fourier Transform homogenization of additively manufactured fiber reinforced composites from component-wise description of morphologySosa-Rey Facundo, Vella Clement, Lingua Alessandra, Pierre Juliette, Piccirelli Nicola, Therriault Daniel, Lévesque Martindoi:10.1016/j.compscitech.2023.110261根据成分形态描述对增材制造的纤维增强复合材料进行多尺度快速傅立叶变换均质化处理The process-structure–property relationship in short-fiber reinforced composites made in Fused Filament Fabrication (FFF) remains inadequately understood, much trial-and-error and extensive testing is required to use these materials for load-bearing applications. As a consequence, the largely empirical design process has hindered the adoption of this technology, notably due to the lack of reliable structural analysis capability. In order to surpass the limitations of mechanical property prediction using simplified artificial microstructures, this work demonstrates the decisive advantage of using geometries obtained directly from imaging of printed specimen instead. The analysis of μ-CT images is performed via a purpose-built extraction tool called OpenFiberSeg, yielding profound insight into the process-structure relation. The use of real microstructures is shown to considerably improve the mechanical behavior prediction capability via dual-scale FFT-based homogenization, bringing relative error margins below 5%, for full anisotropic description. It also becomes possible to investigate the effect of processing parameters such as nozzle diameter and printing pattern on morphological properties and on mechanical behavior, revealing the magnitude of the spatial variation of local properties. The combination of experimental and simulation enables insight that is not accessible to either alone. Original imaging data and source code are made publicly available.人们对熔融长丝制造（FFF）工艺制造的短纤维增强复合材料的工艺-结构-性能之间的关系仍然缺乏足够的了解，要将这些材料用于承重应用，还需要进行大量的试错和测试。因此，由于缺乏可靠的结构分析能力，主要依靠经验的设计过程阻碍了这种技术的应用。为了超越使用简化人工微结构进行机械性能预测的局限性，这项工作展示了使用直接从打印试样成像中获得的几何形状的决定性优势。对 μ-CT 图像的分析是通过一种名为 OpenFiberSeg 的专用提取工具进行的，从而深入了解了工艺与结构之间的关系。通过基于双尺度 FFT 的均质化，使用真实的微观结构大大提高了力学行为预测能力，使全各向异性描述的相对误差率低于 5%。此外，还可以研究喷嘴直径和印刷模式等加工参数对形态特性和机械行为的影响，揭示局部特性的空间变化幅度。实验与模拟的结合使我们能够深入了解单靠其中任何一种方法都无法获得的信息。原始成像数据和源代码已公开发布。 来源：复合材料力学仿真Composites FEM
