今日更新：Composite Structures 1 篇，Composites Part A: Applied Science and Manufacturing 2 篇，Composites Science and Technology 1 篇Composite StructuresPeriodic magnetically oriented gradient structures with flower-like surface for enhancing microwave absorption efficiencyLirui Wang, Miao Yu, Hao Zhang, Mi Zhudoi:10.1016/j.compstruct.2024.118121具有花状表面的周期性磁定向梯度结构提高微波吸收效率In order to overcome the inherent trade-off between magnetic absorber's effective absorption, filling concentration, and thickness while achieving real-time control over the effective absorption bandwidth (EAB) below −10 dB, periodic magnetically oriented gradient structures featuring flower-like surfaces that can be reconfigured using magnetic induction technology. The arch test results demonstrated that even with particle filling concentration of only 30 wt%, reflection loss (RL) of the magnetically oriented periodic gradient structures achieved −37.5 dB, and EAB could be extended to 6.5 GHz, outperforming samples 60 wt%-0 mT. Especially for samples 50 wt%-100 mT, which EAB with four distinct peaks in its EAB reaching 10.5 GHz. This was due to magnetically-oriented macro–micro structure that facilitated to reduce hyperosmotic threshold of conductive loss network of absorbing material. Meanwhile, the gradient structure with flower-like surface was conducive to absorption peaks, impedance matching patterns and electromagnetic wave scattering. The reconfigurable structure was also found to have remarkably stability, maintaining its nearly uniform electromagnetic loss capability even after 3 months. This study is scientifically important for establishing the regulatory mechanism of orientation distribution structure on EAB and absorption resonance peaks, as well as providing an experimental and theoretical foundation for exploring low detectable and electromagnetic protection devices.为了克服磁性吸收体的有效吸收、填充浓度和厚度之间的固有权衡，同时实现对有效吸收带宽(EAB)低于- 10 dB的实时控制，可以使用磁感应技术重新配置具有花状表面的周期性磁定向梯度结构。拱形测试结果表明，即使颗粒填充浓度仅为30 wt%，磁取向周期性梯度结构的反射损耗(RL)也达到- 37.5 dB, EAB可以扩展到6.5 GHz，优于60 wt%-0 mT的样品。特别是对于50 wt%-100 mT的样品，其EAB有四个明显的峰，达到10.5 GHz。这是由于磁性取向的宏观微观结构有利于降低吸收材料导电损失网络的高渗透阈值。同时，具有花状表面的梯度结构有利于吸收峰、阻抗匹配模式和电磁波散射。可重构结构还具有显著的稳定性，即使在3 个月后仍保持其几乎均匀的电磁损耗能力。本研究对于建立取向分布结构对EAB和吸收共振峰的调控机制，为探索低可探测和电磁保护装置提供实验和理论基础，具有重要的科学意义。Composites Part A: Applied Science and ManufacturingElectric-field-assisted fabrication of metal-class thermal-conductive and elastomer-class-flexible composites comprising plasma-surface-modified hexagonal boron nitride and polyrotaxaneRui Hasegawa, Kenichi Inoue, Hitoshi Muneoka, Tsuyohito Ito, Kazuhiro Kirihara, Yoshiki Shimizu, Yukiya Hakuta, Kohzo Ito, Kazuo Terashimadoi:10.1016/j.compositesa.2024.108197 电场辅助制备含等离子体表面改性六方氮化硼和聚轮烷的金属类导热和弹性体类柔性复合材料There is a growing demand for materials with high thermal conductivity, electrical insulation, flexibility, and toughness for application in flexible electronic devices. To develop materials with the aforementioned properties, composites comprising the flexible and tough polyrotaxane (PR) and highly thermally conductive hexagonal boron nitride particles (hBN) were fabricated in this study. An electric field was applied during the polymerization of the composites to improve their thermal conductivity in the out-of-plane direction of the composites without reducing their flexibility. Electric-field application during polymerization controlled the orientation of hBN in the as-synthesized composites, forming pillar-like structures comprising oriented hBN. The particle diameter and concentration of hBN were optimized to synthesize an electrically insulating composite with elastomer-class flexibility in the in-plane direction (a low Young’s modulus of 77 MPa) and metallic-alloy-class thermal conductivity in the out-of-plane direction (>10 W/mK) with a wide range of potential applications including thermal interface materials in electronic devices.在柔性电子器件中，对具有高导热性、电绝缘性、灵活性和韧性的材料的需求日益增长。为了开发具有上述性能的材料，本研究制备了由柔性和坚韧的聚轮烷(PR)和高导热六方氮化硼颗粒(hBN)组成的复合材料。在复合材料的聚合过程中施加电场以提高复合材料在面外方向的导热性，同时又不降低复合材料的柔韧性。聚合过程中的电场作用控制了hBN在合成的复合材料中的取向，形成了由取向hBN组成的柱状结构。优化了hBN的粒径和浓度，合成了一种面内弹性级(低杨氏模量77 MPa)和面外导热系数(>10 W/mK)的金属合金级电绝缘复合材料，具有广泛的应用前景，包括电子器件中的热界面材料。Towards automated characterisation of fatigue damage in composites using thermoelastic stress analysisW.J.R. Christian, P. Lambert, I.E. Tabrizi, C.A. Middleton, C. Przybyla, E.A. Pattersondoi:10.1016/j.compositesa.2024.108205利用热弹性应力分析实现复合材料疲劳损伤的自动化表征Composite materials demonstrate complicated fatigue behaviour due to their microstructure and the varied types of defects that can occur during loading. This necessitates experimentation to determine their performance under loading. In this study an algorithm is introduced for identifying and categorising different defects forming during fatigue tests. Thermoelastic stress analysis was used to obtain high spatial and temporal resolution stress information from the surface of notched composite specimens. Specimens with three different geometries were loaded in tension–tension fatigue to failure. An algorithm was used to identify when and where matrix cracking and delaminations formed within the specimens as well as quantify how this changed over time. By improving how damage events are identified and characterised, the algorithm reduces the amount of time needed to process experimental fatigue data and helps to provide greater understanding of fatigue processes in new materials from early small-scale cracking all the way to final failure.复合材料由于其微观结构和在加载过程中可能出现的各种类型的缺陷而表现出复杂的疲劳行为。这就需要通过实验来确定它们在载荷下的性能。本文提出了一种识别和分类疲劳试验中不同缺陷的算法。采用热弹性应力分析方法获取了缺口复合材料表面的高时空分辨率应力信息。三种不同几何形状的试件在拉伸-拉伸疲劳状态下加载至破坏。使用一种算法来确定样品中何时何地形成基质开裂和分层，并量化其随时间的变化情况。通过改进损伤事件的识别和表征方式，该算法减少了处理实验疲劳数据所需的时间，并有助于更好地理解新材料的疲劳过程，从早期的小规模开裂一直到最终失效。Composites Science and TechnologyMultiscale simulation study on radiation aging of EPDM and preparation of radiation-resistant materialsXueting Wang, Chaokun Huang, Xin Wang, Yanlong Luo, Xiujuan Wangdoi:10.1016/j.compscitech.2024.110595 EPDM辐射老化的多尺度模拟研究及耐辐射材料的制备With the wide application of ethylene propylene diene monomer (EPDM) in the field of nuclear engineering, exploring the irradiation aging mechanism of EPDM is of great significance to improve the radiation resistance of EPDM composites. In this paper, the radiation aging mechanism of EPDM was investigated by a combination of experiments and multiscale simulations, and EPDM composites with excellent radiation resistance were prepared. The radiation aging mechanism of EPDM involves the crosslinking and degradation of molecular chains. The aging of EPDM starts from the breakage of α-H in the 5-ethylidene-2-norbornene monomer. In addition, the screening strategy of radiation-resistant additives was proposed. Antioxidants N, N'-diphenyl-p-phenylene-diamine (H), N, N'-ditolyl-p-phenylenediamine (DTPD), and N, N'-di-2-naphthyl-p-phenylenediamine (DNP) were taken as the main research objects, and quantitative analysis was carried out from the aspects of chemical protection and physical protection. The screening results showed that DNP has excellent radiation resistance and migration resistance. The prepared EPDM-DNP composites showed outstanding radiation resistance with 94% tensile strength retention after 300 kGy irradiation. This work contributes to understand the mechanisms of radiation-induced material damage and guides the design of radiation-resistant materials.随着EPDM在核工程领域的广泛应用，探索EPDM辐照老化机理对提高EPDM复合材料的耐辐射性能具有重要意义。本文采用实验与多尺度模拟相结合的方法，研究了EPDM的辐射老化机理，制备了具有优异耐辐射性能的EPDM复合材料。EPDM的辐射老化机制涉及分子链的交联和降解。EPDM的老化始于5-乙基-2-降冰片烯单体中α-H的断裂。此外，提出了抗辐射添加剂的筛选策略。以抗氧化剂N, N′-二苯基-对苯二胺(H)、N, N′-二酰基-对苯二胺(DTPD)和N, N′-二-2-萘基-对苯二胺(DNP)为主要研究对象，从化学保护和物理保护两方面进行了定量分析。筛选结果表明，DNP具有优良的耐辐射性和抗迁移性。制备的EPDM-DNP复合材料在300 kGy辐照条件下具有优异的抗辐射性能，抗拉强度保持率达94%。这项工作有助于理解辐射材料损伤的机理，并指导抗辐射材料的设计。来源：复合材料力学仿真Composites FEM
