【新文速递】2023年11月10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 2 篇，Composites Part B: Engineering 3 篇，Composites Science and Technology 1 篇

Composite Structures

Advances in composite phase change materials based on high performance three-dimensional (3D) skeletons: Properties, strategies and applications

Qian Runda, Liu Meng, Lu Xitao, Qing Chunyao, Zou Deqiu

doi:10.1016/j.compstruct.2023.117711

基于高性能三维（3D）骨架的复合相变材料的进展：性能、策略和应用

Phase change materials (PCM) have received widespread attention due to their outstanding advantages, such as high latent heat, little temperature fluctuation, and good chemical and physical stability. However, the low thermal conductivity and leakage of PCM significantly limit their applications. The efficient strategy of using high thermal conductivity materials to construct three-dimensional (3D) skeletons for encapsulating PCM is widely considered to simultaneously improve thermal conductivity and structure stability. Herein, this paper reviews the recent research progress on enhancing the thermal performance and structure stability of PCM through the construction of 3D skeletons using various methods, including low-dimensional material assembly, foam templates, and 3D printing strategies. The construction strategies of 3D skeleton from the micro (low-dimensional material assembly) to the macro (foam templates and 3D printing) are highlighted and compared. Furthermore, diverse applications are summarized and analyzed. Finally, challenges, opportunities and solutions are put forward.

相变材料（PCM）具有潜热高、温度波动小、化学和物理稳定性好等突出优点，因此受到广泛关注。然而，PCM 的低导热性和泄漏问题极大地限制了其应用。人们普遍认为，使用高导热材料构建三维（3D）骨架来封装 PCM，是同时提高导热性和结构稳定性的有效策略。本文综述了近年来通过采用各种方法（包括低维材料组装、泡沫模板和三维打印策略）构建三维骨架来提高 PCM 的导热性能和结构稳定性的研究进展。重点介绍并比较了从微观（低维材料组装）到宏观（泡沫模板和三维打印）的三维骨架构建策略。此外，还对各种应用进行了总结和分析。最后，提出了挑战、机遇和解决方案。

Analysis of the Transfer, Flexural Bond and Anchorage Lengths of Pretensioned FRP Reinforcement Based on Eurocode

Jokūbaitis Aidas, Valivonis Juozas

doi:10.1016/j.compstruct.2023.117712

基于欧洲规范的预拉伸玻璃钢加固的传递、挠曲粘结和锚固长度分析

Current design codes in North America have guidelines for assessing the anchorage zone of pretensioned fiber reinforced polymer (FRP) reinforcement. However, there is no comparison of the Eurocode approach with experimental data or suggestions for its application for prestressed FRP reinforcement. Therefore, the main objective of this article is to provide a comparison of available data in the literature on the transfer, flexural bond, and anchorage length of different types of FRP reinforcement with Eurocode and to provide insight on the adaptation of this code. The database of more than 300 and 100 specimens with the results of the transfer and flexural bond lengths is used, respectively. This database is used to derive and propose the parameters that describe the type and surface of pretensioned FRP reinforcement based on the Eurocode approach. Furthermore, the influence of shear reinforcement and the type of pretensioned reinforcement release (gradual and sudden) is taken into account. The Eurocode approach with the coefficients proposed for different FRP reinforcements on average gave the best prediction of the experimental transfer, flexural bond, and anchorage length results compared to the North American design codes for FRP reinforcement and the Eurocode for steel strands.

北美现行的设计规范有评估预应力纤维增强聚合物（FRP）加固锚固区的指导原则。然而，目前还没有将欧洲规范方法与实验数据进行比较，也没有将其应用于预应力玻璃钢加固的建议。因此，本文的主要目的是将文献中关于不同类型 FRP 加固的传递、挠曲粘结和锚固长度的现有数据与 Eurocode 进行比较，并对该规范的适应性提出见解。数据库中分别有 300 多个和 100 多个试样的传递长度和挠曲粘结长度结果。该数据库用于根据欧洲规范方法推导和提出描述预应力玻璃钢加固类型和表面的参数。此外，还考虑了剪力加固和预应力加固释放类型（渐进和突然）的影响。与北美玻璃钢加固设计规范和欧洲钢绞线规范相比，欧洲规范方法以及针对不同玻璃钢加固提出的系数平均对实验转移、挠曲粘结和锚固长度结果给出了最佳预测。

An efficient multi-objective optimization framework for thin-walled tubular deployable composite boom

Bai Jiang-Bo, You Fei-Yan, Wang Zhen-Zhou, Fantuzzi Nicholas, Liu Qing, Xi Hao-Tian, Bu Guang-Yu, Wang Yong-Bin, Wu Shi-Qing, Feng Rui, Liu Tian-Wei

doi:10.1016/j.compstruct.2023.117713

 

薄壁管式可展开复合吊杆的高效多目标优化框架

As a crucial structural component in space applications such as solar sails and solar arrays, the thin-walled tubular deployable composite booms (DCBs) demonstrate extensive utilization by employing stored elastic strain energy to achieve folding and deploying functions. This paper introduces a multi-objective optimization framework that integrates an analytical model with a genetic algorithm. By utilizing a multi-objective evolutionary algorithm based on de-composition (MOEA/D), the optimization objectives of minimizing folding moment and maximizing bending stiffness are pursued. Multiple constraints associated with failure avoidance, laminate stacking sequence design principles, and the folding moment range of actuator in the folding mechanism are considered in the optimization. The multi-objective optimization design of the tubular DCBs is performed to obtain the optimal combinations of cross-sectional radius, central angle, and ply scheme. Experimental validation confirms the efficacy of the optimization results. Additionally, an in-depth analysis on the influence of genetic algorithm types, hyperparameters, and different design variables on the optimization outcomes is thoroughly discussed. The findings of this study offer significantly insights for the practical engineering applications of tubular DCBs.

薄壁管状可展开复合材料吊杆（DCBs）是太阳帆和太阳能电池阵列等空间应用中的重要结构部件，通过利用存储的弹性应变能实现折叠和展开功能，显示了其广泛的利用价值。本文介绍了一种将分析模型与遗传算法相结合的多目标优化框架。通过利用基于去分解的多目标进化算法（MOEA/D），实现了折叠力矩最小化和弯曲刚度最大化的优化目标。在优化过程中，考虑了与避免故障、层压板堆叠顺序设计原则和折叠机构中执行器的折叠力矩范围相关的多个约束条件。对管状 DCB 进行多目标优化设计，以获得横截面半径、中心角和层叠方案的最佳组合。实验验证证实了优化结果的有效性。此外，还深入分析了遗传算法类型、超参数和不同设计变量对优化结果的影响。这项研究的结果为管状 DCB 的实际工程应用提供了重要启示。

Ultrasonic lamination defects detection of carbon fiber composite plates based on multilevel LSTM

Zhang Fengyi, Wang Lihua, Ye Wenjing, Li Yan, Yang Fan

doi:10.1016/j.compstruct.2023.117714

基于多层次 LSTM 的碳纤维复合板超声波层压缺陷检测

During the production of carbon fiber composites (CFC), various forming methods and complex processes can introduce different types of defects, with lamination defects being a major concern. In this paper, we propose a multilevel Long Short-Term Memory (LSTM) neural network combined with ultrasonic detection to identify the lamination defects in carbon fiber composites. Unlike conventional ultrasonic detection that requires multiple sets of probes, this method only employs a one-to-one transmission and reception mode. The COMSOL-Multiphysics finite element software is utilized to simulate the ultrasonic transmission and generate the necessary ultrasonic data. By incorporating multiple levels of learning, the accuracy and convergence of the traditional LSTM can be obviously enhanced. This approach uses ultrasound waveform data collected from a single set of probes to predict the locations and sizes of lamination defects. Based on fewer than 10000 datasets where each dataset represents a waveform, the numerical results demonstrate a prediction accuracy of over 90% for defect position and size. Moreover, the multilevel LSTM method exhibits convergence, and incorporating more data can further promote the prediction accuracy. This method offers a time-saving, labor-saving, and cost-effective solution for detecting and analyzing defects in CFC.

在碳纤维复合材料（CFC）的生产过程中，各种成型方法和复杂的工艺会带来不同类型的缺陷，其中层压缺陷是一个主要问题。本文提出了一种结合超声波检测的多层次长短期记忆（LSTM）神经网络，用于识别碳纤维复合材料中的层压缺陷。与需要多组探头的传统超声波检测不同，该方法只采用一对一的发射和接收模式。利用 COMSOL-Multiphysics 有限元软件模拟超声波传输并生成必要的超声波数据。通过多层次的学习，传统 LSTM 的准确性和收敛性得到明显提高。这种方法使用从单组探头采集的超声波波形数据来预测层压缺陷的位置和大小。基于不到 10000 个数据集（每个数据集代表一个波形），数值结果表明缺陷位置和尺寸的预测准确率超过 90%。此外，多层次 LSTM 方法表现出收敛性，加入更多数据可进一步提高预测精度。该方法为检测和分析氟氯化碳缺陷提供了一种省时、省力且经济有效的解决方案。

Fused deposition modeling to predict inter-layer weld strength of polyvinylidene fluoride and its MWCNTs-reinforced composites

Zhang Huiying, Xiao Jie, Chen Ye, Wang Huaping

doi:10.1016/j.compstruct.2023.117715

通过熔融沉积建模预测聚偏氟乙烯及其 MWCNT 增强复合材料的层间焊接强度

Fused deposition modeling (FDM) printed parts have poor mechanical properties in comparison to injection molding parts, which is attributed to the insufficient welding of extrusion filaments at the inter-layer adhesion interface. This paper proposes a methodology for predicting and analyzing the weld strength of FDM printed parts using poly(vinylidene fluoride) (PVDF) as the raw material. A temperature field simulation and weld strength prediction are established and used to predict inter-layer weld strength. The relative error between predicted weld strength and the experimental value of FDM printed PVDF under different parameters is small, indicating that the method has good accuracy. Moreover, it can be extended to PVDF composites with different MWCNTs content, exhibiting good versatility. This method provides valuable theoretical guidance for the research of polymer composites in FDM process and offers opportunities for the application of FDM in specific fields.

与注塑成型部件相比，熔融沉积成型（FDM）印刷部件的机械性能较差，其原因在于挤出丝在层间粘合界面的焊接不充分。本文提出了一种预测和分析以聚偏氟乙烯（PVDF）为原料的 FDM 印刷部件焊接强度的方法。本文建立了温度场模拟和焊接强度预测模型，并将其用于预测层间焊接强度。在不同参数下，预测的 FDM 印刷 PVDF 焊接强度与实验值之间的相对误差很小，表明该方法具有良好的准确性。此外，该方法还可扩展至不同 MWCNTs 含量的 PVDF 复合材料，具有良好的通用性。该方法为 FDM 工艺中聚合物复合材料的研究提供了有价值的理论指导，为 FDM 在特定领域的应用提供了机会。

Crashworthiness study of tubular lattice structures based on triply periodic minimal surfaces under quasi-static axial crushing

Wan Mincen, Hu Dayong, Zhang Hongbo, Pi Benlou, Ye Xubin

doi:10.1016/j.compstruct.2023.117703

 

准静态轴向挤压下基于三重周期性极小曲面的管状晶格结构的耐撞性研究

This study explored the crashworthiness performance of four types of tubular lattice structures based on triply periodic minimal surfaces (named TPMS-T)—Diamond, Gyroid, IWP, and Primitive. Their axial crushing behaviors were examined by experiments and numerical simulation, and compared against typical tubes. TPMS-T outperformed traditional tubes in terms of crashworthiness. Subsequently, the effects of the relative density (ρ), density gradient and hybrid design on the crushing behaviors of TPMS-T were analyzed numerically. Results showed that ρ had a significant effect on crashworthiness performance and deformation modes, and density gradient and hybrid design could lead to lower initial peak crushing force (Fp), higher specific energy absorption (SEA), and larger crushing force efficiency (CFE). Finally, numerical investigations of the improved TPMS-T structures were shown to enhance crashworthiness performance through interaction with tube walls.

本研究探讨了四种基于三重周期性极小表面（命名为 TPMS-T）的管状晶格结构--金刚石结构、陀螺结构、IWP 结构和原始结构--的防撞性能。实验和数值模拟检验了它们的轴向挤压行为，并与典型管材进行了比较。在耐撞性方面，TPMS-T 优于传统钢管。随后，数值分析了相对密度（ρ）、密度梯度和混合设计对 TPMS-T 挤压行为的影响。结果表明，ρ 对防撞性能和变形模式有显著影响，密度梯度和混合设计可使初始峰值破碎力（Fp）更低、比能量吸收（SEA）更高、破碎力效率（CFE）更大。最后，对改进后的 TPMS-T 结构进行的数值研究表明，该结构可通过与管壁的相互作用提高耐撞性能。

Towards Composite Suspension Control Arm: Conceptual Design, Structural Analysis, Laminate Optimization, Manufacturing, and Experimental Testing

Komurcu E., Kefal A., Abdollahzadeh M.A., Basoglu M.F., Kisa E., Yildiz M.

doi:10.1016/j.compstruct.2023.117704

迈向复合悬架控制臂：概念设计、结构分析、层压优化、制造和实验测试

The automotive industry needs composite materials to decrease the weight of new-generation vehicles whilst increasing their strength. In this study, one of the critical (load bearing) components of automobiles, i.e., the suspension control arm made of steel, is fully redesigned for its suitable manufacturing using composite materials. To this end, innovative mechanical simulation methods are developed and coupled to perform the design, analysis, and optimization of the automotive suspension control arm. The main design/optimization criteria are set to reduce no less than 75% weight of the metal control arm and increase its safety by at least 60% by using composite materials and a new geometry suitable for mass production. To predict the deformation-stress state of the control arm, a four-node quadrilateral shell element is implemented based on the kinematics of refined zigzag theory (RZT). Once verified numerically, the computer implementation of the RZT is combined with the optimization algorithm to achieve the optimum laminate stacking sequence of the control arm. Accordingly, prototypes of the composite control arms with optimum lamination plans are manufactured and then experimentally tested under the loading and constraint conditions defined at the conceptual design stage. The numerical and full-scale experimental results are compared, and the RZT models are comprehensively validated. Hence, the advantages of the overarching design-analysis-optimization strategy presented herein are revealed for redesigning and manufacturing automobile parts from composite materials.

汽车工业需要复合材料来减轻新一代汽车的重量，同时提高其强度。在本研究中，对汽车的关键（承重）部件之一，即钢制悬挂控制臂，进行了全面的重新设计，以适合使用复合材料制造。为此，开发了创新的机械模拟方法，并将其与汽车悬架控制臂的设计、分析和优化相结合。主要的设计/优化标准是通过使用复合材料和适合大规模生产的新几何形状，将金属控制臂的重量减轻不少于 75%，并将其安全性提高至少 60%。为了预测控制臂的变形应力状态，根据精炼之字形理论（RZT）的运动学原理，采用了四节点四边形壳元素。经过数值验证后，将 RZT 的计算机实现与优化算法相结合，以实现控制臂的最佳层叠顺序。因此，在概念设计阶段确定的加载和约束条件下，制造了具有最佳层叠计划的复合材料控制臂原型，然后进行了实验测试。对数值结果和全尺寸实验结果进行了比较，并对 RZT 模型进行了全面验证。因此，本文提出的总体设计-分析-优化策略的优势在用复合材料重新设计和制造汽车零件方面得到了体现。

Composites Part A: Applied Science and Manufacturing

Facile fabrication Ni@SiO2/C derived from polysilsesquioxane as strong and broadband microwave absorbers with infrared stealth, flame retardant, and water resistant functions

Du Hanying, Ren Jiaqi, Zhang Donglin, Li Xiang, Zhang Wenchao, Yang Rongjie

doi:10.1016/j.compositesa.2023.107884

 

聚硅氧烷衍生的 Ni@SiO2/C 易于制造，可作为具有红外隐身、阻燃和防水功能的强力宽带微波吸收体

It remains a great challenge for magnetic/carbon-based microwave absorbers to achieve both strong and broadband absorption, especially at ultra-low filling ratio. Herein, nickel nanoparticles supported on porous silica/carbon composite (Ni@SiO2/C) derived from POSS was prepared by a facile method. The carbonized Ni@SiO2/C composite offers the following advantages: i) the three-dimensionally porous POSS-derived SiO2/C skeleton provides electron transport paths and enhances conductive dissipation; ii) the porous magnetic/carbon composite provides interfacial polarization to enhance dielectric loss and forms strong magnetic coupling network to enhance magnetic loss; iii) multiple reflections and scattering between the porous framework enhance electromagnetic waves attenuation. Notably, the optimized Ni15@SiO2/C750 achieves high reflection loss of −58.5 dB, and broad effect absorption bandwidth of 8 GHz with a thickness of 2 mm at an ultra-low filling ratio of 3 wt%. Besides, the Ni15@SiO2/C750 has multiple properties of infrared stealth, flame retardancy, and water resistance.

对于磁性/碳基微波吸收器来说，实现强吸收和宽带吸收仍然是一个巨大的挑战，尤其是在超低填充比的情况下。在此，我们采用一种简便的方法制备了支撑在由 POSS 衍生的多孔二氧化硅/碳复合材料（Ni@SiO2/C）上的镍纳米粒子。碳化镍@SiO2/C复合材料具有以下优点：i）三维多孔POSS衍生的SiO2/C骨架提供了电子传输路径，增强了导电耗散；ii）多孔磁/碳复合材料提供了界面极化，增强了介电损耗，并形成了强磁耦合网络，增强了磁损耗；iii）多孔框架之间的多重反射和散射增强了电磁波衰减。值得注意的是，优化后的 Ni15@SiO2/C750 在 3 wt%的超低填充率下实现了 -58.5 dB 的高反射损耗和 8 GHz 的宽效应吸收带宽，厚度为 2 mm。此外，Ni15@SiO2/C750 还具有红外隐身、阻燃和防水等多重特性。

How to regulate moisture-induced stresses in composites: The answer from nanostructure of S2 layer in Wood cell wall

Chen Mingyang, Zhang Chi, Ke Liao-Liang

doi:10.1016/j.compositesa.2023.107889

如何调节复合材料中由湿气引起的应力：木材细胞壁 S2 层纳米结构的答案

S2 layer of the Wood cell wall is fundamentally a biocomposite with strong hygroscopicity and undergoes significant changes in mechanical properties upon water adsorption. How the internal stress develops during the adsorption process is still unclear. By employing a multi-scale modeling scheme, we successfully resolve the stress distributions within the S2 layer at different moisture levels. We find that the shear stress developed on the fibril-matrix interface is much smaller than that of ordinary fiber-reinforced composites with the same geometrical dimensions due to the heterogeneous nature of the microfibrils. Besides, we demonstrate that the stress developed during dehydration is larger than that during hydration, which is attributed to the fact that the amorphous polymers comprising the matrix suffer from softening upon water adsorption. These unraveled mechanisms can deepen people’s understanding on the origin of the moisture-induced stress in the S2 layer.

木材细胞壁的 S2 层从根本上说是一种生物复合材料，具有很强的吸湿性，吸水后机械性能会发生显著变化。吸附过程中的内应力是如何形成的，目前还不清楚。通过采用多尺度建模方案，我们成功地解析了不同湿度条件下 S2 层内部的应力分布。我们发现，由于微纤维的异质性，在纤维-基体界面上产生的剪应力远小于具有相同几何尺寸的普通纤维增强复合材料。此外，我们还证明了脱水过程中产生的应力大于水合过程中产生的应力，这是因为构成基体的无定形聚合物在吸水后发生了软化。这些机制的揭示可以加深人们对 S2 层中水分诱导应力来源的理解。

Composites Part B: Engineering

Inner superhydrophobic materials based on waste fly ash: Microstructural morphology of microetching effects

Pang Bo, Zheng Heping, Jin Zuquan, Hou Dongshuai, Zhang Yunsheng, Song Xiaoyun, Sun Yanan, Liu Zhiyong, She Wei, Yang Lin, Li Mengyuan

doi:10.1016/j.compositesb.2023.111089

基于废弃粉煤灰的内超疏水性材料：微蚀效应的微观结构形态

Superhydrophobic technology in construction can effectively improve the barrier ability of the substrate to harmful water-based erosion media, among which the coating scheme is the most practical choice at present, but it may easily fail due to mechanical damage. Therefore, the current research focus has shifted to the development of internal superhydrophobic materials (ISMs) that maintain stable hydrophobicity even under harsh conditions of use and do not rely on expensive fluor-based surface modifications. In this study, the topological structure of waste denitrification fly ash (FA) was constructed using an innovative method, by precisely controlling the etching medium concentration and the form of FA, a one-step process was developed to create ISM with excellent matrix strength and strong waterproof properties. In this study, the alkaline environment generated by FA hydration was used to induce the silica-hydrogen bond dehydrogenation of polymethylhydrosiloxane (PMHS) and the free ammonium ion deamination to toughen the film; PMHS and liquid phase are used to produce the oil-water phase, and the oil film adheres to the surface of the generated NASH and sodium silicate crystals; The porous inner surface of ISM is formed with hydrogen- and ammonia-induced rough structure; The synthesized ISM retains superhydrophobicity and less compressive strength reduction value, and its superhydrophobicity even at damaged or friction interfaces. The material preparation method provides a good foundation and innovative design concept for the seepage prevention and maintenance of concrete structures, the construction of aerated FA bricks, the preparation of foam insulation materials, and the batch utilization of waste FA.

建筑中的超疏水技术可以有效提高基材对有害水基侵蚀介质的阻隔能力，其中涂层方案是目前最实用的选择，但它很容易因机械损伤而失效。因此，目前的研究重点已转向开发即使在苛刻的使用条件下也能保持稳定疏水性的内部超疏水性材料（ISM），而不依赖于昂贵的氟基表面改性。本研究采用创新方法构建了废弃脱硝粉煤灰（FA）的拓扑结构，通过精确控制蚀刻介质的浓度和 FA 的形态，开发出一种一步法工艺，从而制造出具有优异基体强度和强大防水性能的 ISM。在这项研究中，利用 FA 水合产生的碱性环境诱导聚甲基氢硅氧烷（PMHS）的硅氢键脱氢和游离铵离子脱氨以增韧薄膜；利用 PMHS 和液相产生油水相，油膜附着在生成的 NASH 和硅酸钠晶体表面；ISM的多孔内表面形成氢气和氨气诱导的粗糙结构；合成的ISM保持超疏水性，抗压强度降低值较小，即使在损坏或摩擦界面也能保持超疏水性。该材料制备方法为混凝土结构的防渗和养护、加气 FA 砖的建造、泡沫保温材料的制备以及废弃 FA 的批量利用提供了良好的基础和创新的设计理念。

Evolution of stiffness in flax yarn within flax fiber reinforced composites during moisture absorption

Wang Jingjing, Li Yan, Li Qian, Long Yu, Yu Tao, Li Zhuo

doi:10.1016/j.compositesb.2023.111096

吸湿过程中亚麻纤维增强复合材料中亚麻纱线刚度的变化

This study aims to investigate the evolution of stiffness in flax yarn within flax fiber reinforced composites (FFRCs) during moisture absorption, focusing on the influence of moisture content on the microstructure of flax fibers. To characterize the hygroscopic mechanical behaviors of flax yarns in FFRCs, the hygroscopicity and tensile properties of dried and impregnated flax yarns were tested at various humidity levels. A multi-scale modeling approach was utilized to simulate the stiffness in flax yarn within FFRCs, encompassing the modeling of cell wall layers of the flax elementary fiber, flax elementary fiber and twisted flax yarn. Specifically, the variation trends of the microfiber angle (MFA) in the S2 layer and the stiffness degradation of the combined amorphous matrix (CAM) with respect to relative moisture content (RMC) were proposed and determined through simulation and inversion calculation. The study reveals that the MFA in the S2-layer is the most crucial parameter affecting the longitudinal elastic properties of flax yarn in FFRCs, while the stiffness degradation of the CAM significantly influences the transverse elastic properties. Finally, this study establishes a relationship between the overall stiffness of flax yarn in FFRCs and the RMC. This relationship provides a parameter foundation for accurately predicting the mechanical properties of FFRCs during moisture absorption.

本研究旨在探讨亚麻纤维增强复合材料（FFRC）中的亚麻纱在吸湿过程中刚度的变化，重点研究含水率对亚麻纤维微观结构的影响。为了描述亚麻纱在亚麻纤维增强复合材料中的吸湿机械性能，在不同湿度水平下测试了干燥和浸渍亚麻纱的吸湿性和拉伸性能。采用多尺度建模方法模拟了 FFRC 中亚麻纱的刚度，包括亚麻基本纤维、亚麻基本纤维和加捻亚麻纱的细胞壁层建模。具体而言，通过模拟和反演计算，提出并确定了 S2 层的微纤维角 (MFA) 以及组合无定形基质 (CAM) 的刚度随相对含水率 (RMC) 变化的趋势。研究表明，S2 层中的 MFA 是影响 FFRC 中亚麻纱纵向弹性性能的最关键参数，而 CAM 的刚度退化对横向弹性性能有显著影响。最后，本研究确定了 FFRC 中亚麻纱的整体刚度与 RMC 之间的关系。这种关系为准确预测 FFRC 在吸湿过程中的机械性能提供了参数基础。

A comparative study on the oxidation behavior and failure mechanisms of conventional NiCoCrAl alloy and in-situ composite AlCoCrFeNi2.1 eutectic high-entropy alloy at 1300 °C

Lu Jie, Zhang Han, Ren Guoliang, Chen Ying, Luo Lirong, Cai Huangyue, Shan Xiao, Zhang Xiancheng, Zhao Xiaofeng

doi:10.1016/j.compositesb.2023.111097

传统镍钴铬铝合金与原位复合 AlCoCrFeNi2.1 共晶高熵合金在 1300 °C 下的氧化行为和失效机理对比研究

We present a comparative study on oxidation behavior and failure mechanisms of conventional NiCoCrAl alloys doped with Y and Hf (CNA) and in-situ composite AlCoCrFeNi2.1 eutectic high-entropy alloy doped with Y and Hf (ISC-EHEA) at 1300 °C. We demonstrate that the ISC-EHEA has much stronger resistance to surface rumpling and oxide spallation than CNA. Hybrid molecular dynamics (MD) and Monte Carlo (MC) simulations show that the diffusion coefficients of the metal elements in the Al-depletion layer of the ISC-EHEA are 50 % lower than those in the CNA. The low diffusion coefficients lead to low growth stress in the thermally grown Al2O3 scale on the ISC-EHEA and improve the creep resistance of the metal in contact with the scale, thus preventing the occurrence of rumpling. The oxidation rate constant of the ISC-EHEA is ∼32 % lower in comparison to those of the CNA, which is attributed to the coarser columnar Al2O3 grains that effectively mitigate grain boundary diffusion. The rumpling-free metal/oxide interface, the low residual stress and the low oxide growth rate for the ISC-EHEA result in strong resistance to scale spallation. Owing to the strong scale/alloy bonding at the interface and the build-up of strain energy during prolonged oxidation, damage in the Al2O3 scale on the ISC-EHEA is initiated as surface cracks rather than interface decohesion. When re-oxidized at 1300 °C, the ingress of oxygen along the surface cracks results in fast growth of new oxides at the metal/oxide interface, which causes local stress concentration, interface crack propagation and scale spallation.

我们对掺杂 Y 和 Hf 的传统镍钴铬铝合金（CNA）和掺杂 Y 和 Hf 的原位复合 AlCoCrFeNi2.1 共晶高熵合金（ISC-EHEA）在 1300 ℃ 下的氧化行为和失效机理进行了比较研究。我们证明，ISC-EHEA 比 CNA 具有更强的抗表面隆起和氧化物剥落能力。混合分子动力学（MD）和蒙特卡罗（MC）模拟显示，ISC-EHEA 的铝耗尽层中金属元素的扩散系数比 CNA 中的扩散系数低 50%。低扩散系数导致 ISC-EHEA 上热生长的 Al2O3 鳞片的生长应力较低，提高了与鳞片接触的金属的抗蠕变性，从而防止了皱褶的发生。与 CNA 相比，ISC-EHEA 的氧化速率常数降低了 ∼32 %，这归因于更粗的柱状 Al2O3 晶粒有效地减缓了晶界扩散。ISC-EHEA 的金属/氧化物界面无褶皱、残余应力低、氧化物生长率低，因此具有很强的抗鳞片剥落能力。由于界面上的鳞片/合金结合力很强，以及长时间氧化过程中应变能的积累，ISC-EHEA 上的 Al2O3 鳞片损坏是以表面裂纹而不是界面脱粘的形式出现的。当在 1300 °C 下再次氧化时，氧气沿表面裂纹进入，导致金属/氧化物界面上新氧化物快速生长，造成局部应力集中、界面裂纹扩展和鳞片剥落。

Composites Science and Technology

Mechanical, thermal insulation, and ablation behaviors of needle-punched fabric reinforced nanoporous phenolic composites: The role of anisotropic microstructure

Cai Hongxiang, Niu Bo, Qian Zhen, Li Tong, Wang Peng, Li Liang, Cao Yu, Zhang Yayun, Long Donghui

doi:10.1016/j.compscitech.2023.110325

 

针 刺织物增强纳米多孔酚醛复合材料的机械、隔热和烧蚀行为：各向异性微结构的作用

Needle-punched fabric reinforced nanoporous phenolic composite (NPC) is a kind of promising ablative thermal protection material for spaceflight. However, in practical applications, typically anisotropic microstructure of NPC may lead to different performances and damage mechanisms under various directional mechanical or thermal loads. Herein, NPC is prepared and cut into specimens along three typical plane directions including XY-plane (0°), Z-plane (90°), and transitional-plane (45°), and their mechanical, thermal insulation, and ablation behaviors are systematically investigated. Benefiting from the woven fabric in XY-plane, NPC in 0°-plane direction exhibits highest tensile strength (169.2 ± 12.6 MPa), and CT image-based simulation further verifies that woven fabrics are primary load-bearing structure. Meanwhile, NPC in 45°-plane direction shows highest compressive strength (443.1 ± 18.2 MPa) but low compressive stress at low strain, demonstrating a weak bonding between two layers of woven fabrics. Moreover, the heat transfer simulation indicates that horizontally stacked woven fabrics effectively protect the internal material from thermal erosion, thus NPC in 0°-plane direction exhibits optimal thermal insulation. The ablation testing and micro-CT observations further demonstrate that the angle between woven fabric and thermal load significantly influences the ablation mechanism. The present work will further promote the structural reliability and optimization of needle-punched composites.

针 刺织物增强纳米多孔酚醛复合材料（NPC）是一种很有前途的航天烧蚀热保护材料。然而，在实际应用中，NPC 典型的各向异性微观结构可能导致其在不同方向的机械或热负荷下具有不同的性能和损坏机制。本文制备了 NPC，并沿三个典型的平面方向（包括 XY 平面（0°）、Z 平面（90°）和过渡平面（45°））切割成试样，系统地研究了它们的机械、隔热和烧蚀行为。得益于 XY 平面上的编织物，0° 平面方向的 NPC 拉伸强度最高（169.2 ± 12.6 兆帕），基于 CT 图像的模拟进一步验证了编织物是主要的承重结构。同时，45° 平面方向的 NPC 显示出最高的抗压强度（443.1 ± 18.2 兆帕），但低应变时的抗压应力较低，这表明两层编织物之间的粘结力较弱。此外，热传导模拟表明，水平堆叠的编织物能有效保护内部材料免受热侵蚀，因此 0° 平面方向的 NPC 具有最佳的隔热性能。烧蚀测试和显微 CT 观察进一步证明，编织物与热负荷之间的角度对烧蚀机制有显著影响。本研究将进一步促进针 刺复合材料的结构可靠性和优化。