【新文速递】2024年4月24日复合材料SCI期刊最新文章

   

今日更新：Composite Structures 3 篇，Composites Part A: Applied Science and Manufacturing 3 篇，Composites Part B: Engineering 10 篇

Composite Structures

Numerical investigation of bond-slip behaviour between CFRP strips and concrete in shear tests under static and blast loads

Azer Maazoun, Mohamed Ben Rhouma, Stijn Matthys, David Lecompte, Ahmed Siala

doi:10.1016/j.compstruct.2024.118148

静力和爆破荷载作用下CFRP条与混凝土粘结滑移特性的数值研究

The paper is structured into two main sections. In the first part, the focus is on the finite element (FE) analysis of bond slip in a single bond shear test between concrete and carbon fiber reinforced polymer (CFRP) strips under static loads. To model the test set-up, a plastic damage material model and an elastic material model are used for the concrete prism and the unidirectional CFRP strip respectively. Three approaches, including a perfect bond model, a cohesive bond model, and contact algorithms based on recent bond slip models, are employed to simulate the bond interface. The numerical model's validity is confirmed through comparison with experimental results from the literature. The paper predicts the debonding failure mode, the strain evolution along the bond length, and the delamination loads of the CFRP strip. The cohesive bond model exhibits good agreement between numerical and experimental data. In the second part of the paper, the developed FE model is tested under blast loading and compared to the experimental results of the blast tests conducted by the authors. The experimental and numerical findings highlight a significant dynamic enhancement effect on bond-slip properties due to the propagation of the blast wave within the concrete and the high loading rate.

本文主要分为两个部分。在第一部分中，重点对静荷载作用下混凝土与碳纤维增强聚合物(CFRP)条单键剪切试验中的粘结滑移进行了有限元分析。为了模拟试验装置，分别对混凝土棱柱和单向CFRP条采用塑性损伤材料模型和弹性损伤材料模型。采用完美键模型、内聚键模型和基于最新键滑移模型的接触算法三种方法对键界面进行了模拟。通过与文献实验结果的比较，验证了数值模型的有效性。本文预测了CFRP条的脱粘破坏模式、应变沿粘接长度的演化以及分层荷载。内聚键模型与实验数据吻合较好。在论文的第二部分，对所建立的有限元模型进行了爆炸载荷下的试验，并与作者进行的爆炸试验结果进行了对比。实验和数值结果表明，由于爆炸冲击波在混凝土内部的传播和高加载率，对粘结滑移性能有显著的动态增强作用。

Compressive properties and energy absorption of 4D printed auxetic mechanical metamaterials

Bingxun Li, Xiaozhou Xin, Cheng Lin, Liwu Liu, Yanju Liu, Jinsong Leng

doi:10.1016/j.compstruct.2024.118135

4D打印形变机械超材料的压缩性能和能量吸收

Auxetic mechanical metamaterials contract or expand laterally when subjected to compressive or tensile load in the axial direction and offer potential benefits in areas such as flexible electronics, aerospace, and soft actuators. Nevertheless, when metamaterials are fabricated using conventional methods, their configurations and properties are fixed, which prohibits adaptation to the specific geometric requirements of their application environment. This limits their further development. This paper proposes an auxetic mechanical metamaterial with a negative Poisson's ratio and energy absorption capability. Compression specimens are fabricated with LCD photo-curable printing technology. The deformation mechanism and in-plane compression characteristics are examined through experimental and numerical simulation methods. The influence of unit cell geometrical control parameters on Poisson's ratio and energy absorption are also explored. The results indicate the dominant deformation mechanism of metamaterial during in-plane compression is bending deformation. The negative Poisson's ratio behavior is more pronounced when compressing along the X direction than along the Y direction, and the specimens also exhibit energy absorption capacity. In addition, the metamaterials prepared by 4D printing technology can be transformed from one configuration to another under external stimuli stimulation and force, and exhibit different mechanical properties, realizing programmable and reconfigurable, further expanding their application range.

当受到轴向压缩或拉伸载荷时，辅助机械超材料会横向收缩或膨胀，在柔性电子、航空航天和软执行器等领域具有潜在的优势。然而，当使用传统方法制造超材料时，它们的结构和性质是固定的，这就禁止了对其应用环境的特定几何要求的适应。这限制了它们的进一步发展。提出了一种具有负泊松比和能量吸收能力的机械辅助超材料。采用LCD光固化印刷技术制备压缩试样。通过实验和数值模拟的方法研究了其变形机理和面内压缩特性。探讨了单元胞几何控制参数对泊松比和能量吸收的影响。结果表明，超材料在面内压缩过程中的主要变形机制是弯曲变形。沿 X 方向压缩时，负泊松比行为比沿Y方向压缩时更为明显，且试样也表现出能量吸收能力。此外，利用4D打印技术制备的超材料可以在外界刺 激和力的作用下从一种形态转变为另一种形态，并表现出不同的力学性能，实现了可编程和可重构，进一步扩大了其应用范围。

Transient heat conduction in multi-material topology optimization of thermoelastic structures involving dynamic constraints

Minh-Ngoc Nguyen, Dongkyu Lee

doi:10.1016/j.compstruct.2024.118144

涉及动力约束的热弹性结构多材料拓扑优化中的瞬态热传导

This work presents a modified solid isotropic material with penalization (SIMP) for conducting dynamic-constrained multi-material topology optimization (MMTO) of thermoelastic structures subjected to transient thermal conduction. The novelty of this study is the multi-material optimization of instantaneous temperature conduction under specific frequency constraints, which has never been studied before. The proposed method has been developed for general models of multi-material interpolations such as thermal stiffness, heat capacity, and thermal stress coefficient. The temperature environment is formulated by applying prescribed mechanical and thermal loads that are exposed over a period of time. In this work, we focus on the objective of minimizing compliance in a transient heat conduction structure while simultaneously imposing constraints on the dynamics. With high temperatures, the stiffness of the optimization results decreases while stability is still guaranteed. The sensitivity of the objective function is subsequently calculated using the discretize-then-differentiate approach for the dynamic problem as well as the adjoint variable method. This study examines the impact of thermal fields and different time increments in conjunction with dynamic criteria. The outcomes of heat conduction result in notable alterations under identical dynamic constraint levels.

本文提出了一种带有惩罚(SIMP)的改进固体各向同性材料，用于进行瞬态热传导热弹性结构的动态约束多材料拓扑优化(MMTO)。本研究的新颖之处在于特定频率约束下的多材料瞬时温度传导优化，这是以前从未研究过的。该方法适用于多材料插值的一般模型，如热刚度、热容和热应力系数。温度环境是通过施加在一段时间内暴露的规定的机械和热负荷来制定的。在这项工作中，我们专注于最小化瞬态热传导结构的顺应性，同时对动力学施加约束。在高温下，优化结果的刚度降低，但仍能保证稳定性。然后利用动态问题的先离散后微分法和伴随变量法计算目标函数的灵敏度。本研究结合动态标准考察了热场和不同时间增量的影响。在相同的动力约束水平下，热传导结果有显著的变化。

Composites Part A: Applied Science and Manufacturing

Novel application of dual-nozzle 3D printer for enhanced in-situ impregnation 3D printing of dry continuous fiber reinforced composites

Kui Wang, Yangyu Huang, Ping Cheng, Yi Xiong, Antoine Le Duigou, Yong Peng, Yanni Rao, Said Ahzi

doi:10.1016/j.compositesa.2024.108231

双喷嘴3D打印机在干法连续纤维增强复合材料原位增强浸渍3D打印中的新应用

This work reported a novel two-stage in-situ impregnation method for additively manufacturing dry fiber bundles reinforced polymer composites using a commercial dual-nozzle 3D printer. This process allowed simultaneous manufacturing of both continuous fiber prepreg filaments and continuous fiber reinforced polymer composites (CFRPCs). Initially, it was demonstrated that the two-stage in-situ impregnation method significantly enhanced the printing geometrical accuracy of specimens filled with rigid continuous carbon fiber. Subsequently, the tensile performance of CFRPCs, filled with twisted continuous ramie yarns and unwound continuous carbon fiber bundles, printed using single-stage and two-stage in-situ impregnations was compared. Significantly, the two-stage in-situ impregnation method facilitated a marked improvement in the tensile strength and modulus of CFRPCs. This improvement proved the enhanced impregnation effect of fibers, validating the effectiveness of the proposed two-stage in-situ impregnation approach for dry fiber bundles reinforced composites.

本工作报道了一种新的两阶段原位浸渍方法，用于使用商用双喷嘴3D打印机增材制造干纤维束增强聚合物复合材料。该工艺允许同时制造连续纤维预浸长丝和连续纤维增强聚合物复合材料(cfrpc)。结果表明，两阶段原位浸渍法显著提高了硬质连续碳纤维填充试件的打印几何精度。随后，比较了单段原位浸渍和两段原位浸渍法制备的连续苎麻纱线和未缠绕连续碳纤维束填充cfrpc的拉伸性能。两段原位浸渍法显著提高了cfrpc的抗拉强度和模量。这一改进证明了纤维的增强浸渍效果，验证了所提出的两阶段原位浸渍方法对干纤维束增强复合材料的有效性。

A coupled data-physics computational framework for temperature, residual stress, and distortion modeling in autoclave process of composite materials

Yongjia Xu, Ze Zhao, Kalyan Shrestha, Waruna Seneviratne, Shakya Liyanage, Upul Palliyaguru, Anand Karuppiah, Jim Lua, Nam Phan, Jinhui Yan

doi:10.1016/j.compositesa.2024.108218

复合材料热压灭菌过程中温度、残余应力和变形建模的耦合数据物理计算框架

It is challenging to obtain the full-field temperature profile during autoclave processes to control the temperature uniformity and minimize the residual stress and distortion of cured composite structures. This paper proposes a coupled data-physics computational framework for full-field temperature reconstruction and the subsequent residual stress/distortion modeling by using limited monitoring temperature data. Firstly, a Long Short-Term Memory (LSTM) model is developed for full field temperature reconstruction. In this LSTM model, a cross-recombination method is proposed to maximize the value of monitored temperature data. The method effectively cuts through the bottleneck of neural network training with limited labeled data. The LSTM model’s prediction stability is enhanced based on the mean-teacher and ensemble learning strategy. To train and validate the proposed method, we perform experiments using an autoclave at the National Institute for Aviation Research (NIAR). The LSTM model’s accuracy is assessed by comparing its predicted results with the thermocouple (TC) data from measurements and high-fidelity simulation data from computational fluid dynamics (CFD). The study shows that the proposed LSTM model can effectively reconstruct the full-field temperature using limited monitoring data and significantly improve accuracy and efficiency compared with the CFD-based counterpart. Then, we create a coupled data-physics computational framework by embedding the data-driven LSTM model into a physics-based thermo-mechanical finite element model to predict residual stress and distortion. The simulation results show that the coupled data-physics framework provides an effective way for process-to-performance modeling and simulation of autoclave curing processes.

为了控制温度均匀性，减少固化复合材料结构的残余应力和变形，在热压灭菌过程中获得全场温度分布是一项挑战。本文提出了一种耦合数据-物理计算框架，用于利用有限的监测温度数据进行全场温度重建和随后的残余应力/变形建模。首先，建立了一种长短期记忆(LSTM)模型，用于全场温度重建。在该LSTM模型中，提出了一种交叉重组方法，使监测温度数据的价值最大化。该方法有效地突破了标记数据有限的神经网络训练瓶颈。采用均值教师和集成学习策略增强了LSTM模型的预测稳定性。为了训练和验证所提出的方法，我们使用国家航空研究所(NIAR)的高压灭菌器进行实验。通过将LSTM模型的预测结果与热电偶(TC)测量数据和计算流体动力学(CFD)的高保真模拟数据进行比较，评估了LSTM模型的准确性。研究表明，与cfd模型相比，所提出的LSTM模型可以利用有限的监测数据有效地重建全场温度，并显著提高了精度和效率。然后，我们通过将数据驱动的LSTM模型嵌入到基于物理的热-机械有限元模型中，创建了一个耦合的数据-物理计算框架，以预测残余应力和变形。仿真结果表明，耦合数据-物理框架为热压釜固化过程的过程-性能建模和仿真提供了有效途径。

Measurement of tensile and shear strength of interfacial bonding in fiber reinforced soft composites combining experiments and simulation

Yatao Xu, Jiaqi Zhu, Licheng Zhou, Bao Yang, Zejia Liu, Yiping Liu, Liqun Tang, Zhenyu Jiang

doi:10.1016/j.compositesa.2024.108221

纤维增强软质复合材料界面粘结抗拉与剪切强度的实验与模拟相结合

Interfacial bonding strength plays a key role in the mechanical performance of fiber reinforced polymers. However, measurement of interfacial bonding strength in fiber reinforced soft composites (FRSCs) becomes a challenging issue, because the large deformation capability of soft matrix invalidates most of current testing methods. This paper demonstrates an advanced method combining experiments and simulation, which provides a convenient and reliable means to measure both tensile strength and shear strength of interfacial bonding for FRSCs. The specimen is made by embedding a fiber bundle in a soft plate for transverse tensile test. Various stress states along the fiber–matrix interface can be realized by controlling the inclination angle of fiber bundle to the stretching direction. Tensile strength and shear strength of interfacial bonding in FRSCs can be estimated based on the analysis of critical stress states. The comparison with the widely adopted fiber pull-out test indicates that the nominal shear strength obtained in pull-out test is severely underestimated.

界面结合强度对纤维增强聚合物的力学性能起着关键作用。然而，纤维增强软复合材料(FRSCs)界面结合强度的测量成为一个具有挑战性的问题，因为软基体的大变形能力使大多数现有的测试方法失效。本文提出了一种实验与仿真相结合的先进方法，为frsc界面粘结抗拉强度和抗剪强度的测量提供了一种方便可靠的手段。试样是将纤维束埋入软板中进行横向拉伸试验制成的。通过控制纤维束向拉伸方向倾斜的角度，可以实现纤维-基体界面上的各种应力状态。基于临界应力状态的分析，可以估算出frsc界面粘结的抗拉强度和剪切强度。与广泛采用的纤维拉拔试验对比表明，拉拔试验得到的公称抗剪强度严重低估。

Composites Part B: Engineering

Fire-Retardant Anti-Microbial Robust Wood Nanocomposite Capable of Fire-Warning by Graded-Penetration Impregnation

Wenbo Che, Zehui Li, Siqi Huo, Toan Dinh, Min Hong, Cristian Maluk, Youming Yu, Yanjun Xie

doi:10.1016/j.compositesb.2024.111482

 

分级渗透浸渍阻燃抗微生物坚固木纳米复合材料火灾预警性能研究

Wood, renowned for its sustainability, specific strength, and thermal insulation, stands as a highly sought-after sustainable structural material. However, the inherent flammability, decay susceptibility, and inadequate mechanical strength hinder its practical applications in high-rise buildings. Here, we report a groundbreaking solution to fabricate multi-functional fire-retardant wood (M-FRW) through a coupled delignification/impregnation procedure followed by densification treatment. The GO/BA created a hybridized network on the M-FRW surface, while BA molecules penetrated the wood cell. As-created M-FRW exhibits a superior flame retardancy due to the physical barrier and catalytic charring effect of GO/BA, as reflected by an ultrahigh limiting oxygen index value of >75% and an 85% reduction in the peak of heat release rate compared to natural wood. Furthermore, the GO/BA layer of M-FRW has a sensitive fire alarm response and ultralong alarm time (∼11280 s). More impressively, M-FRW exhibits an exceptional ability to inhibit decay fungi, mold fungi, and common bacteria due to the superimposed anti-microbial effect of GO and BA. Additionally, M-FRW shows desirable mechanical and thermal insulation properties. This work provides a facile strategy to fabricate a multi-functional advanced wood nanocomposite, making them hold great potential for various engineering applications, such as intelligent buildings.

木材以其可持续性、特定强度和绝热性而闻名，是一种备受追捧的可持续结构材料。然而，其固有的可燃性、易腐烂性和机械强度不足阻碍了其在高层建筑中的实际应用。在这里，我们报告了一种突破性的解决方案，通过耦合脱木质素/浸渍过程，然后进行致密化处理，来制造多功能阻燃木材(M-FRW)。GO/BA在M-FRW表面形成杂交网络，BA分子穿透木材细胞。由于氧化石墨烯/BA的物理屏障和催化炭化作用，M-FRW表现出优异的阻燃性能，其极限氧指数值>75%，放热率峰值比天然木材降低85%。此外，M-FRW的氧化石墨烯/BA层具有敏感的火灾报警响应和超长的报警时间(~ 11280 s)。更令人印象深刻的是，由于氧化石墨烯和BA的叠加抗微生物作用，M-FRW表现出非凡的抑制腐烂真菌、霉菌真菌和普通细菌的能力。此外，M-FRW表现出理想的机械和隔热性能。这项工作为制造多功能高级木材纳米复合材料提供了一种简单的策略，使其在各种工程应用中具有巨大的潜力，例如智能建筑。

Composite material based on piezoelectric core-shell nanofibers for tactile recognition

Giacomo Selleri, Filippo Grolli, Maria Roberta Randi, Emanuele Maccaferri, Tommaso Maria Brugo, Giovanni Valdrè, Andrea Zucchelli, Davide Fabiani

doi:10.1016/j.compositesb.2024.111494

 

基于压电核壳纳米纤维的触觉识别复合材料

In recent years, self-sensing composite materials based on the direct piezoelectric effect have attracted widespread interest as they combine the composite material's mechanical performances with the piezoelectric phase's sensing capability. In this context, piezoelectric nanofibers exhibit minimal impact on the mechanical structure of the composite – differently from bulky films or ceramic disks - and represent a promising strategy for robotic applications or wearable devices. This work aims to develop a self-sensing laminate based on piezoelectric core-shell nanofibers (PEDOT:PSS-based core and P(VDF-TrFE)-based shell). Each layer of the laminate is made of a flexible epoxy material and embeds aligned nanofibers. By orthogonally overlapping two layers, the intersection points of the matrix-like arrangement of the nanofibers generate a network of piezoelectric pixels, which are responsible for sensing. Such a self-sensing composite material exhibited a noticeable capability to recognize the exact position of a mechanical stimulus on its surface.

近年来，基于直接压电效应的自传感复合材料由于将复合材料的力学性能与压电相的传感能力相结合而引起了广泛的关注。在这种情况下，压电纳米纤维对复合材料的机械结构的影响最小-不同于笨重的薄膜或陶瓷盘-并且代表了机器人应用或可穿戴设备的有前途的策略。本工作旨在开发一种基于压电核-壳纳米纤维(PEDOT:基于pss的芯和P(VDF-TrFE)的壳)的自传感层压板。层压板的每一层都由柔性环氧树脂材料制成，并嵌入对齐的纳米纤维。通过正交重叠两层，纳米纤维的矩阵状排列的交叉点产生一个压电像素网络，负责传感。这种自感知复合材料表现出识别机械刺 激在其表面上的确切位置的显著能力。

Multifunctional Properties of Carbon Nanotube Yarn/Aerogel Laminate Composites

Cecil Evers, Matt Kurilich, Jin Gyu Park, Claire Jolowsky, Kaylee Thagard, Richard Liang

doi:10.1016/j.compositesb.2024.111495

碳纳米管纱/气凝胶层压复合材料的多功能性能

This work explores the multifunctional performance of scalable carbon nanotube (CNT) yarn laminate composites. Tensile, thermal, electrical, and electromagnetic interference (EMI) shielding properties are compared to state-of-the-art unidirectional IM7/5250-4 carbon fiber composite (CFRP). CNT laminates achieved a specific tensile modulus of 249.7 ± 22.3 GPa/(g/cm3), which is over double the specific modulus of the CFRP, while maintaining a specific tensile strength of 1.88 ± 0.17 GPa/(g/cm3) which is comparable to the CFRP. CNT yarn laminates demonstrated superior thermal transport properties, with in-plane thermal conductivity of 75.78 ± 14.3 W/mK, over 13 times higher than the CFRP. CNT yarn laminates were also superior in electrical conductivity, achieving a longitudinal conductivity of 5,359 ± 417 S/cm and transverse conductivity of 36.87 ± 2.55 S/cm. This translated to superior EMI shielding properties, achieving over 100 dB in the X-band, which is nearly double that of the CFRP. Incorporating CNT aerogel interwoven between CNT yarns reduced the large property variance observed in the measurements, demonstrating a multifunctional material with tensile, thermal, and electrical properties superior to the CFRP, while potentially mitigating the scalability challenges inherent to CNT nanomaterials.

本研究探讨了可伸缩碳纳米管(CNT)纱线层压复合材料的多功能性能。拉伸、热、电和电磁干扰(EMI)屏蔽性能与最先进的单向IM7/5250-4碳纤维复合材料(CFRP)相比。碳纳米管层压板的比拉伸模量为249.7±22.3 GPa/(g/cm3)，是CFRP比模量的两倍多，而比拉伸强度为1.88±0.17 GPa/(g/cm3)，与CFRP相当。CNT纱线层压板具有优越的热传递性能，其面内导热系数为75.78±14.3 W/mK，比CFRP高13倍以上。CNT纱线层压板的导电性也很好，其纵向导电性为5359±417 S/cm，横向导电性为36.87±2.55 S/cm。这转化为优越的EMI屏蔽性能，在x波段达到100 dB以上，几乎是CFRP的两倍。将碳纳米管气凝胶交织在碳纳米管纱线之间，减少了测量中观察到的巨大性能差异，展示了一种具有拉伸、热学和电学性能优于CFRP的多功能材料，同时潜在地减轻了碳纳米管纳米材料固有的可扩展性挑战。

Strain rate-dependent behavior of cold-sprayed additively manufactured Al-Al 2 O 3 composites: Micromechanical modeling and experimentation

Saman Sayahlatifi, Zahra Zaiemyekeh, Chenwei Shao, André McDonald, James D. Hogan

doi:10.1016/j.compositesb.2024.111479

 

冷喷涂增材制造al - al2o3复合材料应变速率相关行为:微观力学建模与实验

Metal matrix composites (MMCs) fabricated by cold spray additive manufacturing (CSAM) are increasingly gaining attention as structural materials due to their rapid production and scalability. Herein, the failure behavior of CSAM Al-Al 2 O 3 composites under quasi-static and dynamic compression was studied by an experimentally informed/validated 3D microstructure-based finite element (FE) model. The debonding mechanism was found to grow at a higher rate consequently dampening the particle cracking mechanism when the strain rate rises to dynamic regimes. The stress-bearing capacity of the particles plays a key role in enhancing the flow stress and elongation at failure of the CSAM composite under high strain rates due to the lower propensity of particle cracking. Eventually, the model was exercised to study the microscale failure progression in the material under elevated temperatures. For the first time in the literature, this study informs on the correlation between the microscale failure mechanisms and the mechanical performance of CSAM MMCs at the macro scale across strain rates and temperatures whose outcomes are applicable to the design of next-generation materials with a tailored performance.

冷喷涂增材制造技术(CSAM)制备的金属基复合材料(MMCs)由于其快速生产和可扩展性而越来越受到结构材料的关注。本文采用基于三维微观结构的有限元模型，研究了CSAM Al-Al - 2o3复合材料在准静态和动态压缩下的破坏行为。当应变率上升到动态状态时，发现脱粘机制以更高的速率生长，从而抑制颗粒开裂机制。在高应变速率下，颗粒的应力承载能力对提高CSAM复合材料的流变应力和断裂伸长率起关键作用，因为颗粒的开裂倾向较低。最后，运用该模型研究了高温下材料的微尺度破坏过程。本研究在文献中首次揭示了CSAM mmc微观破坏机制与宏观应变速率和温度下力学性能之间的相关性，其结果可用于设计具有定制性能的下一代材料。

A universal strategy towards the fabrication of ultra-high temperature ceramic matrix composites with outstanding mechanical properties and ablation resistance

Chi Zhang, Ping Hu, Liancai Xun, Yanchun Zhou, Jiecai Han, Xinghong Zhang

doi:10.1016/j.compositesb.2024.111485

制备具有优异力学性能和抗烧蚀性能的超高温陶瓷基复合材料的通用策略

Materials with both excellent mechanical properties and good ablation resistance are urgently needed for the applications of thermal protection system in extreme high temperature oxidizing environments. However, owing to the lack of efficient fabrication processes, the existing materials suffer from either insufficient mechanical properties or poor ablation resistance. Herein, we report a novel solid–liquid combination fabrication strategy that successfully achieves the efficient incorporation of ultra-high temperature ceramics into 3D continuous carbon fiber performs as well as rapid densification. The relative density of the green body approaches the cubic close packing of spherical particles. Using Cf/ZrB2−SiC as an example, the as-prepared composite exhibits outstanding mechanical properties with a flexural strength surpasses 600 MPa and an unprecedented work of fracture of 11851 ± 838 J/m2, which is two orders of magnitude higher than that of the currently reported bulk UHTC matrix composites. Moreover, the high ZrB2 content endows the composites with excellent ablation resistance and is thus capable of maintaining long-term non-ablative conditions at 2500 °C. The strategy possesses remarkable universality and high design flexibility, providing a time-saving and cost-effective universal strategy for the on-demand design and fabrication of high-performance ceramic, carbon, metal, and polymer matrix composites.

在极端高温氧化环境中，热防护系统的应用迫切需要具有优异力学性能和良好抗烧蚀性的材料。然而，由于缺乏有效的制造工艺，现有材料要么存在力学性能不足，要么存在抗烧蚀性差的问题。在此，我们报告了一种新的固液结合制造策略，该策略成功地将超高温陶瓷有效地结合到3D连续碳纤维中，并具有快速致密化的性能。绿体的相对密度接近球形粒子的立方紧密堆积。以Cf/ZrB2−SiC为例，制备的复合材料具有优异的力学性能，其抗折强度超过600 MPa，断裂功达到11851±838 J/m2，比目前报道的块体UHTC基复合材料提高了两个数量级。此外，高ZrB2含量使复合材料具有优异的抗烧蚀性，从而能够在2500℃下长期保持非烧蚀状态。该策略具有显著的通用性和高度的设计灵活性，为高性能陶瓷、碳、金属和聚合物基复合材料的按需设计和制造提供了一种节省时间和成本效益的通用策略。

Rational design of SiBCN ceramics with excellent attenuation to strong electromagnetic-wave-absorbing properties at low frequency

Quan Yang, Pingan Chen, Xiangcheng Li, Yingli Zhu

doi:10.1016/j.compositesb.2024.111486

合理设计具有优良低频衰减、强电磁波吸收性能的SiBCN陶瓷

To achieve strong electromagnetic wave absorbing properties, it is important to have good impedance matching, moderate electrical conductivity, and high polarization loss, particularly at low frequency. However, meeting these requirements for polymer-derived ceramics remains challenging. This paper proposes a simple approach to addressing this challenge by adjusting the crystallinity and defects of SiBCN ceramics. The addition of Sm as a catalyst and tailored heating temperatures were used to create SiBCN ceramics with adjustable crystallinities and defective nanograins. The controlled crystallinity provided good impedance matching, while the tailored defective nanograins offered high polarization loss. The combination of these factors results in high-performance electromagnetic wave absorption, with the SiBCN ceramics achieving a minimum reflection loss of -59.13 dB at 3.6 GHz and an effective attenuation bandwidth of 6.87 GHz with a thickness of 2.22 mm. This study provides an effective strategy for the design and fabrication of strong EMW absorbing materials.

为了获得强的电磁波吸收性能，重要的是具有良好的阻抗匹配，中等的导电性和高的极化损耗，特别是在低频时。然而，满足聚合物衍生陶瓷的这些要求仍然具有挑战性。本文提出了一种简单的方法，通过调整SiBCN陶瓷的结晶度和缺陷来解决这一挑战。通过添加Sm作为催化剂和定制的加热温度，制备了具有可调结晶度和缺陷纳米颗粒的SiBCN陶瓷。控制的结晶度提供了良好的阻抗匹配，而定制的缺陷纳米颗粒提供了高极化损耗。这些因素的结合使得SiBCN陶瓷具有高性能的电磁波吸收性能，在3.6 GHz时的反射损耗最小为-59.13 dB，有效衰减带宽为6.87 GHz，厚度为2.22 mm。本研究为强电磁吸波材料的设计和制造提供了有效的策略。

Enhanced Mechanical Performance of Bamboo Fiber/Polypropylene Composites via Micro-Nano Reinforcing Strategy

Linmin Xia, Jianyu Wu, Han Wang, Zhijian Huang, Rilong Yang, Xuexia Zhang, Fei Guo, Jiqing Li, Yan Yu

doi:10.1016/j.compositesb.2024.111488

利用微纳增强策略增强竹纤维/聚丙烯复合材料力学性能

Developing high-performance plant fiber-reinforced thermoplastic polymer composites using environmentally friendly and cost-effective methods remains a significant challenge. In this study, we present a novel micro-nano strategy for producing robust short bamboo fibers (BFs) reinforced polypropylene (PP) composites (SBFPCs) without the need for chemical modification. Our approach involves the utilization of purified short micron BFs, which is surface-coated with holocellulose nanofibers (HNFs) extracted from bamboo parenchyma cells (BP). Through conventional injection processing, the resulting SBFPCs demonstrate remarkable mechanical enhancements with just a 0.2 wt% addition of HNFs compared to control samples. Notably, the mechanical properties of our SBFPCs surpass those of most reported short plant fiber-reinforced thermoplastic composites. The superior mechanical performance of our SBFPCs can be attributed to several factors, including the use of purified micron BFs with optimal aspect ratios as the primary reinforcement phase, enhanced interfacial mechanical interlocking between BFs and the PP matrix facilitated by the addition of HNFs, and the potential dispersion of HNFs within the PP matrix at submicron or nanoscale as a secondary reinforcement phase. This study highlights the promising application of SBFPCs in engineering areas with stringent mechanical requirements.

利用环保和经济高效的方法开发高性能植物纤维增强热塑性聚合物复合材料仍然是一个重大挑战。在这项研究中，我们提出了一种新的微纳米策略来生产坚固的短竹纤维(BFs)增强聚丙烯(PP)复合材料(sbfpc)，而不需要化学改性。我们的方法是利用纯化的短微米生物纤维，其表面包裹有从竹薄壁细胞(BP)中提取的全息纤维素纳米纤维(HNFs)。通过常规的注射处理，与对照样品相比，只添加0.2 wt%的hnf，得到的sbfpc就表现出显著的机械增强。值得注意的是，我们的sbfpc的机械性能超过了大多数报道的短植物纤维增强热塑性复合材料。我们的sbfpc优异的机械性能可归因于几个因素，包括使用具有最佳长宽比的纯化微米级bf作为主要增强相，添加hnf促进bf与PP基体之间的界面机械联锁，以及hnf在PP基体中在亚微米或纳米尺度上的潜在分散作为次要增强相。该研究突出了sbfpc在机械要求严格的工程领域的应用前景。

Phosphononitrile based bismaleimide electronic packaging substrate with both fire safety and dielectric properties: assisting 5G communication

Yifan Zhou, Wenbin Ye, Wei Liu, Fukai Chu, Weizhao Hu, Lei Song, Yuan Hu

doi:10.1016/j.compositesb.2024.111489

 

具有防火和介电性能的膦腈基双马来酰亚胺电子封装基板:辅助5G通信

Due to the high polarizability of traditional flame retardants, it is difficult to meet the excellent dielectric properties and flame retardancy required for electronic packaging materials. Therefore, we have designed a novel linear polyphosphazene that can balance the dielectric properties and flame retardancy of bismaleimide (BMI) composites. Here, fluorinated aromatic ring structure with the large freedom volume is connected to the main chain of polydichlorophosphazene (PDCP) as a side group, resulting in multifunctional fluorinated linear polyphosphazene (PBTFP). Attributed to the excellent P/N/F combination flame retardant strategy, extremely low polarizability, and large molecular free volume, PBTFP simultaneously improves the dielectric properties and flame retardancy of the BMI composites, including UL-94 rating of V0, and a dielectric constant (Dk) as low as 2.69. In addition, as an elastomer, PBTFP exhibits positive effects on improving the hydrophobicity and toughness of BMI. Therefore, through a simple affinity substitution reaction, we prepared a multifunctional fluorinated linear polyphosphazene modified BMI based electronic packaging substrate material that can be applied to 5G high-frequency communication.

由于传统阻燃剂的高极化率，难以满足电子封装材料所要求的优异介电性能和阻燃性。因此，我们设计了一种新型的线性聚磷腈，可以平衡双马来酰亚胺(BMI)复合材料的介电性能和阻燃性。本文将自由体积大的氟化芳环结构作为侧基与聚二氯磷腈(PDCP)主链相连，得到多功能氟化线性聚磷腈(PBTFP)。由于优异的P/N/F复合阻燃策略、极低的极化率和大的分子自由体积，PBTFP同时提高了BMI复合材料的介电性能和阻燃性，其中UL-94等级为V0，介电常数(Dk)低至2.69。此外，作为弹性体，PBTFP对改善BMI的疏水性和韧性有积极的作用。因此，通过简单的亲和取代反应，我们制备了一种可应用于5G高频通信的多功能氟化线性聚磷腈改性BMI基电子封装衬底材料。

3D Printed Architectured Silicone Composites Containing a UV-Curable Rheological Modifier with Tailorable Structural Collapse

Chengzhen Geng, Zhicheng Ding, Wen Qian, Yu Su, Fengmei Yu, Yaling Zhang, Yanqiu Chen, Yu Liu, Ai Lu

doi:10.1016/j.compositesb.2024.111490

3D打印结构有机硅复合材料含有一种可紫外光固化的流变改性剂，具有可定制的结构崩溃

3D printed silicones, combining the unique physiochemical performances of silicones with the attractive design freedom of additive manufacturing, have aroused intensive interest from academia and industry owing to their attractive applications. Direct writing (DW) was the most used method to enable the 3D printing of silicones, but it was limited by its conflicting rheological requirements. Herein, we present novel design of an ultraviolet (UV)-thermal dual-cure ink for UV assisted DW of silicone composites. A UV curable rheological modifier was key to the ink design, which would not only increase the ink viscosity and yield stress substantially at low contents, but also further enhance its shape-retaining capability during printing by UV-assisted curing. As a result, challenging structures with good mechanical performances and isotropy were printable. Interestingly, the degree of structural collapse for the product could be controlled by tailoring the printing parameters, which proved to be a new design dimension for property manipulation of 3D-printed cellular architectures. Rheology of the inks and boundary conditions for structural collapse were discussed in detail. This work will open new opportunities for the development of 3D-printed silicones with customized architectures and tailored performances.

3D打印有机硅，将有机硅独特的物理化学性能与增材制造具有吸引力的设计自由度相结合，因其具有吸引力的应用而引起了学术界和工业界的强烈兴趣。直接写入(DW)是实现有机硅3D打印最常用的方法，但它受到其相互冲突的流变要求的限制。在此，我们提出了一种新的紫外-热双固化油墨的设计，用于紫外辅助有机硅复合材料的DW。可紫外光固化的流变改性剂是油墨设计的关键，它不仅可以在低含量条件下大幅提高油墨的粘度和屈服应力，还可以进一步增强油墨在紫外光辅助固化过程中的保形能力。因此，具有良好力学性能和各向同性的挑战性结构是可打印的。有趣的是，产品的结构坍塌程度可以通过定制打印参数来控制，这被证明是3d打印细胞结构属性操作的新设计维度。详细讨论了油墨的流变性和结构坍塌的边界条件。这项工作将为具有定制架构和定制性能的3d打印有机硅的开发开辟新的机会。

Grain structure tailoring strategy for heterogeneous lamella SiCp/2024Al composites with exceptional strength-ductility synergy

Kan Liu, Qifeng Cui, Lu Shi, Jingyu Yang, Yunpeng Cai, Yishi Su, Qiubao Ouyang, Di Zhang

doi:10.1016/j.compositesb.2024.111491

具有优异强度-塑性协同作用的非均相片状SiCp/2024Al复合材料的晶粒结构定制策略

In this work, a novel grain structure tailoring strategy using one-stepped planetary ball milling, different from conventional powder metallurgy routes that pre-prepared components with different microstructures and then mixed them up, was implemented to fabricate micro- and nano-sized SiC particles (m- & n-SiCp)/2024Al composites with heterogeneous lamella structure. The controllable transformation from homogeneous to heterogeneous grain structures is achieved via nonuniformly distributed n-SiCps induced local grain refinement. Heterogeneous lamella composites exhibit a superior modulus-strength-ductility synergy of 95.3 GPa in Young’s modulus, 750.7 MPa in tensile strength and 4.9% in uniform elongation, particularly with no less than 145% and 175% improvements in ductility and toughness, compared with homogeneous composites. Compressive stress relaxation experiments were conducted to reveal the structural dependence of plastic deformation behaviors. Sustainedly rising hetero-deformation induced (HDI) stress produced by extra geometrically necessary dislocation (GND) accumulation at heterogeneous soft/hard domain interfaces and sequential activation of multiple dislocation mediated mechanisms based on load transfer in heterogeneous lamella composites contribute to the enhanced strain hardening capacity, which offers intrinsic toughening. Also, extrinsic toughening originates from enhanced microcrack multiplication and crack-tip blunting.

与传统粉末冶金工艺中预先制备不同微观结构组分并将其混合的方法不同，本文采用一步式行星球磨技术制备了具有非均质片层结构的微纳米SiC颗粒(m- & n-SiCp)/2024Al复合材料。通过非均匀分布的n-SiCps诱导的局部晶粒细化，实现了从均匀晶粒到非均匀晶粒的可控转变。非均相片层复合材料的杨氏模量为95.3 GPa，抗拉强度为750.7 MPa，均匀伸长率为4.9%，特别是与均相复合材料相比，延性和韧性分别提高了145%和175%。压应力松弛实验揭示了塑性变形行为的结构依赖性。非均质片层复合材料中，非均质软/硬界面上额外几何必要位错(GND)积累产生的异质变形诱导(HDI)应力持续上升，以及基于载荷传递的多种位错介导机制的顺序激活，有助于增强应变硬化能力，从而提供内在的增韧。此外，外部增韧源于微裂纹增殖增强和裂纹尖端钝化。