今日更新：Composite Structures 8 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Part B: Engineering 11 篇，Composites Science and Technology 7 篇Composite StructuresDamage indicators in unidirectional natural fibre composites under fatigue loadingAli Moghimi-ardekani, Jianqun Hao, Stepan V. Lomov, Jan Ivens, Aart Willem van Vuuredoi:10.1016/j.compstruct.2024.118522单向天然纤维复合材料疲劳载荷下的损伤指标This paper investigates the occurrence of failure under fatigue loading of unidirectional flax fibre composites with different matrices. Various parameters, such as dissipated energy, residual strain, and stiffness, were measured to evaluate fatigue damage and the fatigue life of composites. The results indicate that absolute dissipated energy may not be the most suitable indicator for assessing damage in natural fibre composites when they are subjected to fatigue before reaching failure. The research proposes to rather consider the “loss factor”, defined as the ratio of dissipated energy to total energy stored in each cycle. This indicator appears to provide a more effective means of evaluating fatigue life of the studied composites, especially when compared to the dissipated energy observed during fatigue tests at low stress levels. Fatigue and acoustic emission results indicate that biocomposites with better fibre–matrix adhesion show a delayed damage initiation and propagation, as well as longer fatigue life.研究了不同基体的单向亚麻纤维复合材料在疲劳载荷作用下的失效情况。通过测量耗散能、残余应变和刚度等参数来评价复合材料的疲劳损伤和疲劳寿命。结果表明，当天然纤维复合材料在达到破坏前遭受疲劳时，绝对耗散能可能不是评估其损伤的最合适指标。研究建议考虑“损耗因子”，定义为耗散能量与每个循环中存储的总能量的比值。这一指标似乎为评估所研究复合材料的疲劳寿命提供了一种更有效的手段，特别是与在低应力水平下疲劳试验中观察到的耗散能量相比。疲劳和声发射实验结果表明，具有较好纤维基质粘附性的生物复合材料具有较长的疲劳寿命和较长的损伤萌生和扩展时间。A novel layup process for reducing surface thermal distortion of CFRP laminate reflectorKangcheng Yin, Qingchao Sun, Zhihao Fan, Xiaokai Mu, Fei Wangdoi:10.1016/j.compstruct.2024.118517一种减少CFRP板反射器表面热变形的新型铺层工艺This study proposes a novel anti-symmetric folding layup process to reduce the surface thermal distortion of carbon-fiber-reinforced polymer (CFRP) reflector. Firstly, theoretical equations regarding the influencing factors of surface thermal distortion in CFRP reflector are derived, and the concept and advantages of the anti-symmetric folding layup process are introduced. Secondly, free thermal expansion analysis considering the ply angle misalignment is conducted, showing that the novel process can reduce surface thermal distortion by 36.13 % compared to traditional process. Finally, experimental samples with different layup processes are designed and manufactured, and their surface thermal distortion is detected using shear speckle interferometry. The experimental results show that compared with the traditional symmetric layup process, the double anti-symmetric folding layup process can reduce the surface thermal distortion of CFRP reflector by 32.39 %, demonstrating significant advantages in thermal stability and strong potential for practical engineering applications.针对碳纤维增强聚合物(CFRP)反射器的表面热变形，提出了一种新的反对称折叠叠层工艺。首先，推导了CFRP反射器表面热变形影响因素的理论方程，介绍了反对称折叠叠加工艺的概念和优点;其次，进行了考虑铺层角偏差的自由热膨胀分析，结果表明，与传统工艺相比，新工艺可使表面热变形减少36.13 %。最后，设计并制作了不同铺层工艺的实验样品，并用剪切散斑干涉法检测了其表面热畸变。实验结果表明，与传统的对称铺层工艺相比，双反对称折叠铺层工艺可使CFRP反射器表面热变形降低32.39 %，在热稳定性方面具有显著优势，具有很强的工程实际应用潜力。Shear behavior of pre-damaged RC beams strengthened with UHPFRC-CFRP grid layerJiyang Shen, Hongzhe Dai, Guangchun Zhou, Jun Shidoi:10.1016/j.compstruct.2024.118520UHPFRC-CFRP网格层加固预损伤RC梁的抗剪性能Ultra-high performance fiber reinforced concrete (UHPFRC), incorporating recycled tyre fibers, and carbon fiber-reinforced polymer (CFRP) grid were utilized to strengthen the pre-damaged reinforced concrete beams caused by coupling action of sustained loads and marine environment. The failure modes, characteristic loads, deflection features, and strain behavior of the strengthened beams with various types of UHPFRC, thicknesses of UHPFRC layers, CFRP grid ratios, and CFRP grid layout angles were investigated. The results indicated that they exhibited the typical shear failure, and their characteristic loads increased by 102 %-205 % compared to the undamaged beam. By increasing the thickness of the UHPFRC layer and the CFRP grid ratio, and adopting 45° CFRP layout angle, the cracking stiffness, energy absorption capacity, and shear force sharing ability would be further improved, while adopting the UHPFRC incorporating recycled tyre fibers would decrease the ductility. Moreover, analytical models were developed to calculate the ultimate loads, manifesting reasonable accuracy.采用含再生轮胎纤维的超高性能纤维增强混凝土(UHPFRC)和碳纤维增强聚合物(CFRP)网格对持续荷载和海洋环境耦合作用下的预损伤钢筋混凝土梁进行加固。研究了不同类型UHPFRC加固梁的破坏模式、特征荷载、挠度特征和应变行为，以及UHPFRC层厚度、CFRP格栅比例和CFRP格栅布置角度。结果表明:两榀梁表现出典型的剪切破坏，其特征荷载比未破坏梁增加102 % ~ 205 %;增加UHPFRC层厚和CFRP网格比，采用45°CFRP布置角，可进一步提高其开裂刚度、吸能能力和剪力分担能力，而采用回收轮胎纤维的UHPFRC则会降低其延性。建立了计算极限荷载的解析模型，具有合理的精度。On the random vibration-based progressive fatigue damage detection and classification for thermoplastic coupons under population and operational uncertaintyNiki Tsivouraki, Spilios Fassois, Konstantinos Tserpesdoi:10.1016/j.compstruct.2024.118524人口和操作不确定性下基于随机振动的热塑性材料渐进疲劳损伤检测与分类The problem of vibration-based progressive fatigue damage detection and Fatigue State (FS) determination for thermoplastic coupons is experimentally addressed under significant population and experimental uncertainty. The study involves 13 coupons subjected to tension–tension fatigue testing with interruptions at 10,000-cycle intervals. Utilizing non-parametric random vibration analysis and a robust, uncertainty-tolerant methodology, the research employs Multiple Model Representations of uncertain dynamics through parametric ARMA(AutoRegressive-Moving Average)-type random vibration response modeling. Results, validated by ultrasonic C-Scan testing, reveal (a) the significance of uncertainties, (b) a resonant structural frequency indicating fatigue accumulation, (c) remarkable detection performance, achieving 100 % accuracy even at 10,000 cycles, and (d) FS determination with over 80 % accuracy across all coupons. This study offers promising avenues for automated fatigue damage detection and FS determination in thermoplastic structures, eliminating the need to interrupt their operational cycles.在显著种群和实验不确定性条件下，对热塑性材料基于振动的渐进疲劳损伤检测和疲劳状态确定问题进行了实验研究。该研究涉及13个试件，每隔10,000个周期进行一次拉伸-拉伸疲劳测试。该研究利用非参数随机振动分析和鲁棒、不确定性容忍方法，通过参数ARMA(自回归移动平均)型随机振动响应建模，采用多模型表示不确定动力学。通过超声c扫描测试验证的结果显示:(a)不确定性的重要性，(b)表明疲劳积累的共振结构频率，(c)卓越的检测性能，即使在10,000次循环中也能达到100% %的精度，(d)在所有优惠券中都能达到80% %的精度的FS测定。该研究为热塑性结构的自动疲劳损伤检测和FS测定提供了有希望的途径，消除了中断其操作周期的需要。Strengthening mechanism of TPMS interpenetrating phase composites for bone tissue engineeringHaiqiong Xie, Yiru Wang, Fei Liu, Qian Tang, Junjie Chen, Tao Luo, Xin wang, Xuting Biandoi:10.1016/j.compstruct.2024.118526 TPMS互穿相复合材料骨组织工程强化机理研究Multicomponent functional scaffolds hold great promise as implanted materials with compatible mechanical properties and biological functionalities. Interpenetrating phase composites (IPCs) with biomimetic multiscale porosity were fabricated in this study by additive manufacturing and foaming processes using polymethyl methacrylate (PMMA) and polyurethane foam (PUF), respectively. PMMA creates the macroscopic pores with triply periodic minimal surface (TPMS) structures, while PUF forms microscale porosity interpenetrating within the scaffolds, which has been confirmed by SEM and CT tests. Mechanical testing and finite element analysis (FEA) demonstrated significant enhancements in peak strength, toughness, and energy absorption of the IPCs compared to the scaffold alone, with increases of 134%, 73%, and 236%, respectively. The FEA provided insights into the failure and strengthening mechanisms of the interpenetrating porous structure. The continuous PUF component integrated within the IPCs effectively facilitated stress transfer, impeded crack propagation, and significantly prolonged the stress plateau of the scaffolds. Meanwhile, the PMMA primarily served as the main mechanical load-bearing component, transferring stress to the PUF during the deformation stage, resulting in a highly uniform stress distribution within the scaffolds. This uniform stress distribution creates an environment conducive to effective stress stimulation of the internally growing tissue.多组分功能支架作为一种具有相容力学性能和生物功能的植入材料，具有广阔的应用前景。以聚甲基丙烯酸甲酯(PMMA)和聚氨酯泡沫(PUF)为原料，分别采用增材制造和发泡法制备了具有仿生多尺度孔隙的互穿相复合材料(IPCs)。PMMA形成具有三周期最小表面(TPMS)结构的宏观孔隙，而PUF在支架内部形成微观孔隙互穿，SEM和CT试验证实了这一点。力学测试和有限元分析(FEA)表明，与单独使用支架相比，IPCs在峰值强度、韧性和能量吸收方面有显著提高，分别提高了134%、73%和236%。有限元分析为互穿多孔结构的破坏和强化机制提供了新的思路。集成在IPCs内的连续PUF构件有效促进了应力传递，阻碍了裂纹扩展，显著延长了支架的应力平台。同时，PMMA主要作为主要的机械承重构件，在变形阶段将应力传递给PUF，使得支架内部应力分布高度均匀。这种均匀的应力分布创造了一个有利于内部生长组织的有效应力刺 激的环境。Probabilistic investigation of piezoelectric application for reliability enhancement of composite laminates under edge delaminationAli Delbariani-Nejad, Yi Xiongdoi:10.1016/j.compstruct.2024.118528边缘剥落下压电材料增强复合材料层合板可靠性的概率研究In this research a novel probabilistic numerical approach is developed to investigate the effectiveness of piezoelectric (PZT) to enhance the reliability of composite laminates under edge delamination onset (EDO). To achieve this, finite element (FE) modeling is employed as an implicit limit state function (LSF) based on a quadratic failure criterion and critical length concept. Then, an interactive interface that integrates FE analysis and reliability analysis is established to execute them simultaneously until the convergence condition of the reliability index is satisfied. To verify current FE analysis, the interlaminar stress peaks, and resulting edge delamination probability obtained in this study are compared with available data. Subsequently, the probability of EDO in angle-ply composite laminates under applied longitudinal strain and applied electric field on the PZT layer is assessed using both the first-order reliability method (FORM) and the second-order reliability method (SORM). The Monte Carlo simulation (MCS) is employed to verify the numerical results. Findings reveal that employment of PZT reduces EDO probability. Moreover, as the applied voltage increases, the critical strain required for definite EDO also enhances, and the positive influence of PZT on enhancing reliability becomes more pronounced, particularly with increased thickness under higher applied strain.本文提出了一种新的概率数值方法来研究压电材料(PZT)在边缘脱层(EDO)发生时提高复合材料层合板可靠性的有效性。为此，基于二次失效准则和临界长度概念，将有限元建模作为隐式极限状态函数(LSF)。然后，建立有限元分析与可靠性分析相结合的交互界面，使有限元分析与可靠性分析同时进行，直到可靠性指标满足收敛条件为止。为了验证当前的有限元分析，将本研究得到的层间应力峰值和由此产生的边缘分层概率与现有数据进行了比较。在此基础上，采用一阶可靠度法(FORM)和二阶可靠度法(SORM)对施加在PZT层上的纵向应变和外加电场作用下角层复合材料层板发生EDO的概率进行了评估。采用蒙特卡罗模拟(MCS)对数值结果进行了验证。研究结果表明，PZT的使用降低了EDO的概率。此外，随着外加电压的增加，确定EDO所需的临界应变也增加，PZT对提高可靠性的积极影响更加明显，特别是在高外加应变下厚度增加。Highly thermally conductive BNNS/PANF dielectric composite boards prepared by a facile compression moulding processShen Zhao, Zhixiong Wu, Yemao Han, Di Jiang, Yue Xiang, Zhen Geng, Laifeng Li, Chunjie Xie, Zhicong Miao, Rongjin Huangdoi:10.1016/j.compstruct.2024.118530采用简易压缩成型工艺制备高导热BNNS/PANF介电复合板The structural design of an efficient heat conduction channel is critical for heat dissipation in electronic packaging material. The build of oriented boron nitride nanosheet (BNNS) network inside polymers has attracted much attention due to its excellent thermal conductivity and dielectric properties. However, to fabricate a BNNS/polymer composite, complex method and low thermal conductive resin for binding BNNS network are commonly involved, which severely restrict its facile production and enhancement in thermal conductivity. Herein, by utilizing para-aramid nanofibers (PANF) as assistance to BNNS to form thermal conduction network, we obtained high performance composite boards with good formability and adjustable sizes via a simple compression moulding of the BNNS/PANF aerogels. The composite boards exhibit a remarkable in-plane thermal conductivity of 10.62 W/m K−1 at 50 wt% BNNS loading, outstanding practical thermal management capability, excellent thermal stability, low dielectric constant and loss, showing great potential for electronic packaging applications. This facile construction strategy provides a feasible way for the large-scale production and application of high-performance thermal management materials in the future.高效热传导通道的结构设计是电子封装材料散热的关键。聚合物内部定向氮化硼纳米片(BNNS)网络由于其优异的导热性能和介电性能而备受关注。然而，为了制备BNNS/聚合物复合材料，通常涉及复杂的方法和结合BNNS网络的低导热树脂，这严重限制了其易于制备和提高导热性。本文利用对芳纶纳米纤维(PANF)辅助BNNS形成热传导网络，通过对BNNS/PANF气凝胶进行简单的压缩成型，获得了成形性好、尺寸可调的高性能复合板。在50 wt% BNNS负载下，复合板的面内导热系数为10.62 W/m K−1，具有出色的实际热管理能力，优异的热稳定性，低介电常数和损耗，在电子封装应用中具有很大的潜力。这种简便的施工策略为未来高性能热管理材料的大规模生产和应用提供了可行的途径。Integrated design of flame retardancy, smoke suppression and structure of carbon fiber reinforced vinyl ester resin composites through intercalation of nanofiber membranesMingming Yu, Yuji Chu, Wang Xie, Lin Fang, Liying Zhang, Musu Ren, Jinliang Sundoi:10.1016/j.compstruct.2024.118531通过嵌入纳米纤维膜对碳纤维增强乙烯酯树脂复合材料的阻燃、抑烟和结构进行一体化设计A novel flame-retardant method based on the intercalation of nanofiber flame-retardant membrane has been studied for composite laminates. Compared to traditional additive flame-retardant method, this method is more efficient, does not affect the composite forming process, and can improve the mechanical properties of composite. Nanofiber flame-retardant membranes (FPm) are prepared from polyether sulfone (PES) and pentaerythritol phosphate ester (PEPA) by electrospinning technique and inserted in the interlayer of carbon fiber reinforced vinyl ester resin (CF/VER) composites. The FPm can improve the flame-retardancy and smoke suppression of the CF/VER composites by promoting the charring of interlayer structure and form a barrier layer. The thickness of the FPm and the flame-retardant performance of the composites are positive correlation. At a FPm’s thickness of 50 μm, the limiting oxygen index (LOI) and UL-94 ratings of the CF/VER composites reached 33.5 % and V-1, respectively. The total heat release (THR) and total smoke release (TSP) are reduced by 26.4 % and 30.4 %, respectively. Due to the interlayer enhancement effect of FPm, the mechanical strength and interlaminar fracture toughness of CF/VER composites are also improved. Especially, when the thickness of FPm is 30 μm, the mode I interlaminar fracture toughness (GIC) of the CF/VER composite increased by 17.4 %. while the flexural strength, interlayer shear strength (ILSS), mode II interlaminar fracture toughness (GIIC) and storage modulus (E’) are all enhanced.研究了一种基于纳米纤维阻燃膜嵌入的复合材料层合板阻燃新方法。与传统的添加剂阻燃法相比，该方法效率更高，不影响复合材料成型过程，并能提高复合材料的力学性能。以聚醚砜(PES)和季戊四醇磷酸酯(PEPA)为原料，采用静电纺丝法制备了纳米纤维阻燃膜(FPm)，并将其插入碳纤维增强乙烯基酯树脂(CF/VER)复合材料的夹层中。FPm通过促进层间结构的炭化，形成阻隔层，提高CF/VER复合材料的阻燃性和抑烟性。FPm的厚度与复合材料的阻燃性能呈正相关。在FPm厚度为50 μm时，CF/VER复合材料的极限氧指数(LOI)和UL-94等级分别达到33.5 %和V-1。总放热量(THR)和总排烟量(TSP)分别降低26.4% %和30.4% %。由于FPm的层间增强作用，CF/VER复合材料的机械强度和层间断裂韧性也得到了提高。特别是当FPm厚度为30 μm时，CF/VER复合材料的I型层间断裂韧性(GIC)提高了17.4 %。抗折强度、层间抗剪强度(ILSS)、II型层间断裂韧性(GIIC)和存储模量(E′)均有提高。Composites Part A: Applied Science and ManufacturingDeep learning-based microstructure analysis of multi-component heterogeneous composites during preparationHaozhen Li, Chong Wei, Zixiong Cao, Yi Zhang, Xiaoqiang Lidoi:10.1016/j.compositesa.2024.108437基于深度学习的多组分非均相复合材料制备过程微观结构分析Monitoring microstructure evolution during the preparation has always been a difficult problem in the modification studies of SiC composite matrix. Here, we used X-ray tomography microscopy to observe the microstructure of SiCf/SiC-W-ZrB2 composites at different fabrication stage. Based on deep learning, the tracking of the densification process of matrix-modified SiCf/SiC composites was achieved and its suitability for microstructure reconstruction was also verified. The results showed that the average errors of reconstructed SiCf/SiC, pore and Metal (W/ZrB2) are respectively 7.53%, 8.31% and 0.96% by comparison with the segmentation results. Compared with the experimental results, the average error and the average relative error of reconstructed SiCf/SiC is less than 3% and 3.74%.制备过程中微观结构演变的监测一直是SiC复合材料基体改性研究中的一个难题。本文采用x射线层析显微镜观察了SiCf/SiC-W-ZrB2复合材料在不同制备阶段的微观结构。基于深度学习，实现了基体改性SiCf/SiC复合材料致密化过程的跟踪，并验证了其对微观结构重建的适用性。结果表明，与分割结果相比，重构SiCf/SiC、pore和Metal (W/ZrB2)的平均误差分别为7.53%、8.31%和0.96%。与实验结果相比，重构SiCf/SiC的平均误差和平均相对误差分别小于3%和3.74%。Composites Part B: EngineeringResearch on ultrasonic-stationary shoulder assisted friction stir lap welding of thermoplastic polymer and aluminum alloyKang Yang, Shuaiqiang Nian, Shude Ji, Wei Hu, Jinglin Liu, Lin Madoi:10.1016/j.compositesb.2024.111797热塑性聚合物与铝合金的超声-静肩辅助搅拌摩擦搭接焊研究Friction stir lap welding (FSLW) has advantages on obtaining dissimilar upper polymer and lower aluminum materials joint (polymer/Al joint), and how to heighten the bearing capacity of polymer/Al joint as much as possible is greatly meaningful for the manufacturing industries. In this study, choosing dissimilar polyamide 6 (PA 6) polymer and 6061-T6 aluminum alloy materials as research object, traditional FSLW, stationary shoulder assisted FSLW (SSFSLW) and ultrasonic-stationary shoulder assisted FSLW (U-SSFSLW) processes were compared to understand the mechanism of ultrasonic enhancement on the polymer/Al joint. Firstly, the surface morphologies were studied. Then the analyses of micro/macro-structures, mechanical properties and fracture features were carried out by optical microscopy, scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and tensile tests. Results showed that the lap shear failure load of polymer/Al joint by U-SSFSLW reached 1502 N from 814 N by traditional FSLW, because the addition of ultrasonic avoided the bulged-nodule structures on top surface and the cavity defect in stir zone (SZ), broke the Al anchor in upper plate, enlarge the width of SZ in lower plate, and made the deeper micro-pits and larger dents at the interface between SZ bottom and lower plate. The U-SSFSLW process provides an effective way to fabricate the high-strength hybrid joint of dissimilar upper polymer and lower Al materials.搅拌摩擦搭接(FSLW)在获得不同上部聚合物和下部铝材料的接头(聚合物/铝接头)方面具有优势，如何尽可能提高聚合物/铝接头的承载能力对制造业具有重要意义。本研究以不同的聚酰胺6 (pa6)聚合物和6061-T6铝合金材料为研究对象，比较了传统的FSLW、固定肩辅助FSLW (SSFSLW)和超声-固定肩辅助FSLW (U-SSFSLW)工艺，了解超声增强聚合物/Al接头的机理。首先，对表面形貌进行了研究。采用金相显微镜、扫描电镜、差示扫描量热、x射线衍射和拉伸试验等方法对试样的微观/宏观组织、力学性能和断口特征进行了分析。结果表明:U-SSFSLW对聚合物/Al接头的剪切破坏载荷由传统FSLW的814 N达到1502 N，这是由于超声波的加入避免了聚合物/Al接头上表面的凸起结核结构和搅拌区(SZ)的空腔缺陷，破坏了上板的Al锚，扩大了下板的SZ宽度，使SZ底板与下板交界面产生了更深的微坑和更大的凹痕。U-SSFSLW工艺为制备不同上聚合物与下铝材料的高强度杂化接头提供了一条有效途径。Analysis of factors influencing GFRP shredding energy consumption and the physical properties of the resulting recyclatesShuai Cheng, Nai Yeen Gavin Lai, Kok Hoong Wongdoi:10.1016/j.compositesb.2024.111805影响玻璃钢粉碎能耗及回收物物理性能的因素分析Glass fibre reinforced polymer (GFRP) remains the dominant composite produced globally due to its low cost, high specific mechanical properties and chemical resistance performances. These unique features, however, impose significant recycling challenges for their end-of-life parts. Although there are various recycling technologies available, all of them require the waste GFRP to be reduced in size in order to enhance the recycling process efficiency. In this work, a full factorial design analysis was conducted to identify factors that influenced specific shredding energy consumption, average physical size and resin content of shredded GFRP recyclates. Factors investigated were glass fibre fabric architecture in GFRP wastes (non-crimp and nonwoven), GFRP waste feed rate (10-60 kg/hr) and screen aperture of the shredding process (6-20 mm). It was observed that specific shredding energy was not significantly affected by the fabric architecture but could be reduced by opting for larger screen aperture and/or lower feed rate. However, improvement to shredding energy efficiency was achieved if 6mm diameter screen was selected together with 60 kg/hr feed rate. The 60 kg/hr feed rate was found to be ideal in reducing oversize recyclates content but did not affect the median particle size of the remaining recyclates, which was found to be influenced by screen aperture and fabric architecture. Resin-rich and fibre-rich fractions were identified from the recyclates. The resin content of the former was found to be sensitive to all the studied factors.玻璃纤维增强聚合物(GFRP)由于其低成本、高比机械性能和耐化学性能，仍然是全球生产的主导复合材料。然而，这些独特的功能对其报废部件的回收提出了重大挑战。虽然有各种回收技术，但它们都要求减少废弃GFRP的尺寸，以提高回收过程的效率。本研究采用全因子设计分析，确定影响GFRP碎料粉碎能耗、平均物理尺寸和树脂含量的因素。考察了玻璃钢废料中的玻璃纤维织物结构(无褶和无纺布)、玻璃钢废料进料速度(10-60 kg/hr)和粉碎过程的筛孔(6-20 mm)。观察到，比粉碎能不受织物结构的显著影响，但可以通过选择更大的筛网孔径和/或更低的进料速率来降低。然而，如果选择6mm直径的筛网和60公斤/小时的进给量，则可以提高粉碎效率。60 kg/hr的进料速度在减少超细回收物含量方面是理想的，但不影响剩余回收物的中位粒径，该中位粒径受筛孔和织物结构的影响。从回收物中分离出富树脂和富纤维组分。发现前者的树脂含量对所有研究因素都很敏感。A bidirectional-modification strategy for enhancing the reliability of thermoplastic-metal hybrid joint from atomic-scaleYifan Liu, Jianhui Su, Xinbo Wang, Yunhua Deng, Caiwang Tan, Bo Chen, Xiaoguo Song, Swee Leong Singdoi:10.1016/j.compositesb.2024.111795从原子尺度提高热塑性金属杂化接头可靠性的双向改性策略In this study, a strategy towards thermoplastic-metal hybrid joint via bidirectional modification for high reliability was designed. The chemical bond behavior and conditions at the interface were explored from atomic scale using density functional theory (DFT) calculation. Based on the bonding mechanism, the AZ31B alloy was oxidized and the carboxyl groups (COOH) were introduced in the resin chain to improve the strength of chemical bond. The mechanical property of the designed joint was significantly improved and the tensile-shear strength achieved 22.7 MPa after bidirectional modification, reaching 4.5 times that of untreated joints. It was mainly attributed to the generation of metal-carboxylate bridging complex—a typical strong coordination bond formed between two O atoms in COOH and two diagonal magnesium atoms in MgO. Experimental evidence also suggested the generation of new chemical bond at the CFRTP/AZ31B interface. Finally, the bidirectional modification was proved to be an efficient and reliable method with high industrial adaptability. The current work opened up a novel direction for reliability promotion of thermoplastic-metal hybrid structures.本文设计了一种基于双向改性的高可靠性热塑性金属混合接头设计策略。利用密度泛函理论(DFT)从原子尺度上探讨了界面上的化学键行为和条件。基于键合机理，对AZ31B合金进行氧化处理，在树脂链中引入羧基(COOH)以提高化学键合强度。设计接头的力学性能得到明显改善，双向改性后的抗拉抗剪强度达到22.7 MPa，是未处理接头的4.5倍。这主要是由于在COOH中的两个O原子和MgO中的两个对角镁原子之间形成了典型的强配位键，即金属-羧酸桥接络合物。实验证据也表明在CFRTP/AZ31B界面处产生了新的化学键。最后，证明了双向修正是一种高效可靠的方法，具有较高的工业适应性。本研究为提高热塑性金属混合结构的可靠性开辟了新的方向。Combined Loading of Unreinforced and Z-Pin Reinforced Composite Pi Joints: An Experimental and Numerical StudyJames G. Finlay, Anthony M. Waas, Jonathan Bartley-Cho, Nav Muralirajdoi:10.1016/j.compositesb.2024.111796未加筋与z销加筋复合Pi节点的联合载荷:试验与数值研究Blind predictions of experimental responses of non-reinforced and z-pin reinforced composite pi joints were established using a progressive damage and failure model. The finite element model used a novel mixed-mode cohesive formulation to model intra-laminar and inter-laminar damage. A deliberate meshing strategy was used for cohesive interlayers to capture the interaction between intra- and inter-laminar damage modes. A smeared cohesive zone modeling approach was implemented to efficiently include the effects of z-pinning for the z-pin reinforced specimens. Using material properties obtained through experimental correlation of simpler joint configurations, blind predictions for large element specimens subjected to combined loading (axial compression and push-off loading) were established. To assess the predictive capabilities of the model, experimental and numerical comparisons were made in terms of load-displacement response, critical loads, and failure progression. Comparisons between the experimental results and predictions for the unreinforced joints were found to be in good agreement across the range of compressive loads tested. For the z-pin reinforced joints, initial responses were accurately predicted; however, ultimate loads and the toughening effect of the z-pin reinforcement was overpredicted.采用渐进式损伤破坏模型，建立了非加筋和z销加筋复合材料pi节点试验响应的盲预测模型。有限元模型采用一种新颖的混合模内聚公式来模拟层内和层间损伤。为了捕捉层内和层间损伤模式之间的相互作用，对内聚层采用了刻意的网格划分策略。为了有效地考虑z-pin加固试件的z-pin效应，采用了涂抹黏聚区建模方法。利用简单节理构型实验关联得到的材料特性，建立了大单元试件在轴压和推离联合加载下的盲预测。为了评估模型的预测能力，在荷载-位移响应、临界荷载和破坏进展方面进行了实验和数值比较。在试验结果和预测之间的对比发现，在整个压缩载荷测试范围内，未加筋节点的结果是很好的一致。对于z销加固节点，初始响应预测准确;然而，极限载荷和z销增强的增韧效果被高估了。Pyrolysis process and products characteristics of glass fiber reinforced epoxy resin from waste wind turbine bladesBolin Zhang, Shengen Zhang, Zeyu Yang, Weisheng Liu, Boyu Wu, Mingtian Huang, Bo Liudoi:10.1016/j.compositesb.2024.111803 废风电叶片玻璃纤维增强环氧树脂热解工艺及产物特性研究The installed wind power capacity has reached up to 906 GW globally meaning the usage of wind turbine blades (WTBs) with around 9.06 Mt. The waste WTBs with a rapid growth was estimated to be 72.0 kt in 2022 based on the projected lifetime of 20 years. The recycling of fibers reinforced thermoset polymer from waste WTBs has become a knotty environmental issue. This work aimed at studying the pyrolysis behaviors of a glass fibers reinforced epoxy resin materials from a waste WTBs, and revealing the impacts of pyrolysis atmosphere and temperature on the pyrolysis products. It was found that the black glass fibers with deposited carbon and the clean glass fibers were obtained by pyrolysis in N2 and air, respectively. Both pyrolysis in N2 and air produced the pyrolysis oil and gas with similar compositions. The preferable strength of fibers and yield of oil could be obtained at applicable pyrolysis temperature of 450 °C. The oil yields were 13.17 wt.-% and 11.93 wt.-% by pyrolyzing at 450 °C in N2 and air, respectively. The analysis of pyrolysis pathway suggested that the oxygen promoted the decomposition of epoxy resin into small molecules of gases by pyrolysis in air. The utilization of recycled products gas was also discussed. The findings of this work could provide some suggestions to explore a route with low cost to recycling the waste WTBs by pyrolysis.全球风力发电装机容量已达到906吉瓦，这意味着风力涡轮机叶片(WTBs)的使用量约为906万吨。根据预计20年的使用寿命，2022年快速增长的废弃WTBs估计为72.0万吨。从废旧垃圾中回收纤维增强热固性聚合物已成为一个棘手的环境问题。研究了废废渣中玻璃纤维增强环氧树脂材料的热解行为，揭示了热解气氛和温度对热解产物的影响。结果表明，在N2和空气中分别热解得到沉积碳的黑色玻璃纤维和干净的玻璃纤维。N2热解和空气热解产生的热解油气成分相似。在450℃的热解温度下，纤维的强度和出油率较好。在450°C N2和空气中热解，产油率分别为13.17 wt.-%和11.93 wt.-%。热解途径分析表明，氧气促进环氧树脂在空气中热解成小分子气体。并对再生产物气的利用进行了讨论。本研究结果可为探索低成本热解回收废垃圾的途径提供参考。Fragmentation effect of solvent in recovery of unsaturated polyester resin and its compositesWenli An, Yan Zhang, Junyan Li, Shun Zhang, Chengfeng Shen, Xuehui Liu, Zhishan Su, Shimei Xu, Yu-Zhong Wangdoi:10.1016/j.compositesb.2024.111804 溶剂在回收不饱和聚酯树脂及其复合材料中的破碎效应As the most productive thermosetting polymer, unsaturated polyester resin (UPR) and its composies were difficult to be chemcycled due to the mass transfer barrier in dense network structure. High temperature/pressure and mechanical crushing were usually applied to improve the mass transfer during chemcycling processes, but at the sacrifice of reaction selectivity and fiber integrity. Here, a unique fragmentation effect of aprotic solvents was observed in UPR, which is a non-reactive solvation that has the potential to replace mechanical fragmentation and improve the recyclability of UPR and its composite materials. The solvation was found to be based on the hydrogen bond between the solvent and ester group of UPR through Hansen solubility parameters and molecular dynamics simulation. It was the intermolecular force between the polyester clusters of UPR that was destroyed, leading to the fragmentation of UPR into micron-sized powder. The fragmentation effect is also applicable to other ester-containing polymers and provides a simple, facile, and energy-efficient method for the chemcycling of thermosetting resins, as well as direct exfoliation of reinforced fillers.不饱和聚酯树脂(UPR)及其复合材料作为产量最高的热固性聚合物，由于其密集的网状结构存在传质屏障，使得其化学循环变得困难。在化学循环过程中，通常采用高温/高压和机械破碎来改善传质，但以牺牲反应选择性和纤维完整性为代价。本研究发现，非质子溶剂在UPR中具有独特的破碎效应，这是一种非反应性溶剂化，有可能取代机械破碎，提高UPR及其复合材料的可回收性。通过Hansen溶解度参数和分子动力学模拟，发现UPR的溶剂和酯基之间的氢键是溶剂化的基础。UPR聚酯簇之间的分子间作用力被破坏，导致UPR碎裂成微米大小的粉末。破碎效应也适用于其他含酯聚合物，为热固性树脂的化学循环以及增强填料的直接剥落提供了一种简单、便捷、节能的方法。Induction heating of unidirectional C/PAEK – A thermographic study on eddy current formationY.M. Buser, E.T.M. Krämer, R. Akkerman, W.J.B. Grouvedoi:10.1016/j.compositesb.2024.111789单向C/PAEK的感应加热——涡流形成的热成像研究Induction welding is an attractive assembly method for carbon fibre reinforced thermoplastic composites. Parts are heated through the electromagnetic induction of eddy currents in the electrically conductive network of carbon fibres. Such networks rely (partly) on interlaminar contact incidence between the carbon fibres for unidirectional ply-based composites, rendering eddy current formation stochastic. The present study aims to visualise this stochastic behaviour in order to gain deeper insights into the formation of eddy currents. To this end, various laminates were induction heated using a stationary coil while monitoring the heating patterns using a thermal camera. Similar behaviour was then replicated on ply-scale specimens using a strong direct current. The recorded thermograms highlight that eddy currents are predominantly induced along the different fibre directions present in the lay-up. Moreover, it was demonstrated that ply interfaces have a substantial impact on the (re)distribution of current density within the plies.感应焊是一种极具吸引力的碳纤维增强热塑性复合材料组装方法。零件通过碳纤维导电网络中涡流的电磁感应加热。这种网络(部分地)依赖于单向复合材料碳纤维之间的层间接触，使得涡流的形成是随机的。目前的研究旨在可视化这种随机行为，以便更深入地了解涡流的形成。为此，使用固定线圈对各种层压板进行感应加热，同时使用热像仪监测加热模式。然后，在使用强直流电的大尺度标本上复 制了类似的行为。记录的热图突出表明，涡流主要是沿着铺层中存在的不同纤维方向产生的。此外，还证明了层界面对层内电流密度的(再)分布有实质性的影响。Elastomer-based Soft Syntactic Foam with Broadly Tunable Mechanical Properties and ShapabilityAkanksha Pragya, Natalie Young, Tushar K. Ghoshdoi:10.1016/j.compositesb.2024.111794 具有广泛可调力学性能和可塑性的弹性体软泡沫Fabrication of lightweight composites using thermally responsive expandable microspheres (EM) embedded in an elastomeric matrix to form syntactic foams offers significant opportunities to create functional and structural composites for diverse applications. The morphology of the EM-elastomer composite on the micro- and macro-scales is significantly influenced by the fabrication sequence and parameters (composition, expansion time/temperature, etc.). Herein, we report the morphological evolution of an EM-elastomer composite through the fabrication processes and elucidate the interaction of relevant fabrication parameters. Unlike the majority of published reports on hard EM composites, the in-situ expansion of the closed-cell foam structure within a soft matrix leads to larger void sizes, and the concomitant expansive force of the EM impacts the polymer chain mobility within the soft composite. At the same time, higher EM loading improves the mechanical properties; the evolved microstructure leads to a lightweight but stiff structure. For the first time the report details the thermal expansion of EM under applied pretension, leading to irreversible prestrain-dependent morphological changes toward anisotropic mechanical properties. Additionally, the composites are shaped under constrained expansion. The study provides a comprehensive guide and expands the pathways for the practical application of EM-embedded soft syntactic foams in aerospace, electronics, wearables, robotics, etc.利用热响应可膨胀微球(EM)嵌入弹性基体中形成复合泡沫，制造轻质复合材料，为各种应用提供了创造功能和结构复合材料的重要机会。em -弹性体复合材料在微观和宏观尺度上的形貌受到制备顺序和参数(成分、膨胀时间/温度等)的显著影响。在此，我们报告了em -弹性体复合材料在制造过程中的形态演变，并阐明了相关制造参数的相互作用。与大多数已发表的关于硬EM复合材料的报道不同，软基质内闭孔泡沫结构的原位膨胀导致更大的空隙尺寸，并且EM的伴随膨胀力影响了软复合材料内聚合物链的迁移率。同时，较高的电磁载荷提高了材料的力学性能;进化的微观结构导致了轻而硬的结构。该报告首次详细介绍了EM在施加预张力下的热膨胀，导致不可逆的依赖于预应变的各向异性力学性能的形态变化。此外，复合材料是在约束膨胀下成形的。该研究为em嵌入式软语法泡沫在航空航天、电子、可穿戴设备、机器人等领域的实际应用提供了全面的指导和拓展途径。Laser-assisted Thermoplastic Composite Automated Fiber Placement Robot for Bonding GF/PP Unidirectional Composites and Braided CompositesZheng Zhang, Sheng Wang, Yonglong Ma, Baisong Pan, Min Sun, Guang Zhang, Hao Chai, Jiquan Li, Shaofei Jiangdoi:10.1016/j.compositesb.2024.111798用于粘合GF/PP单向复合材料和编织复合材料的激光辅助热塑性复合材料自动纤维放置机器人Laser-assisted thermoplastic composite automated placement method has been applied to the molding of composites due to its advantages of fast molding speed and high heating efficiency. This study focuses on designing a robot for laser-assisted thermoplastic composite automated fiber placement, employing a modular approach to create a versatile fiber placement head. Control functions, such as electrical circuits, a computer interface, and tension control, were developed. Hybrid laminates, combining GF/PP unidirectional and braided composites, were manufactured by independently adjusting laser power (275 W ∼ 400 W) and compression force (150 N ∼ 400 N). Bonding properties were analyzed using wedge peel tests and microscopic detection, revealing superior toughness in laser-assisted laminates compared to autoclave counterparts. Altering laser power and compression force impacted polypropylene resin distribution, influencing hybrid interlayer peel strength. The inclusion of braided materials and elevated mold temperature proved effective in minimizing lamination warpage in GF/PP laminates.激光辅助热塑性复合材料自动贴片法因其成型速度快、加热效率高等优点，已广泛应用于复合材料的成型。本研究的重点是设计一个激光辅助热塑性复合材料自动纤维放置机器人，采用模块化方法创建一个多功能纤维放置头。控制功能，如电路、计算机接口和张力控制，被开发出来。混合层压板，结合了GF/PP单向和编织复合材料，通过独立调节激光功率(275 W ~ 400 W)和压缩力(150 N ~ 400 N)制造。使用楔形剥离测试和显微检测分析了粘合性能，与高压灭菌器相比，激光辅助层压板具有优越的韧性。改变激光功率和压缩力会影响聚丙烯树脂的分布，影响杂化层间剥离强度。事实证明，在GF/PP层压板中加入编织材料和提高模具温度可以有效地减少层合翘曲。CREEP ASSESSMENT OF THERMOPLASTIC MATERIALS FOR NON-STRUCTURAL COMPONENTS IN MARINE ENGINESJacopo Bardiani, Serena Bertagna, Luca Braidotti, Alberto Marinò, Vittorio Bucci, Claudio Sbarufatti, Andrea Manesdoi:10.1016/j.compositesb.2024.111800船用发动机非结构部件用热塑性材料的蠕变评定The substitution of metals with fiber-reinforced polymers represents a well-established practice in the automotive and aerospace industries, driven by advantages such as cost reduction, weight savings, and environmental benefits. In the marine engineering sector, there is a growing interest in this metal replacement trend, particularly for non-structural components of marine engines that can be produced by adopting proper fiber-reinforced thermoplastic polymers. However, evaluating the suitability of such materials for marine applications necessitates a thorough understanding of their creep behavior, given the demanding operational environments and strict safety standards. The material selection process must intricately consider the material's susceptibility to creep through tailored material design methodologies. Moreover, redesign activities should aim to leverage the material's creep-resistant properties while ensuring adequate strength and simplifying installation procedures. Unfortunately, unlike the automotive industry, testing innovative plastic components in real environments on working engines is quite impossible. Neither engine manufacturers nor owners would allow jeopardizing their machinery by installing technologies not yet certified in a delicate environment such as a ship’s engine room. In this context, finite element simulations offer a valuable tool to assess the material's creep performance and validate the proposed design when experimental measurements cannot be performed, hence predicting the component behavior over its intended lifetime. This study aims to exploit finite element analysis to evaluate the creep behavior and suitability for marine engine applications of a fiber-reinforced thermoplastic material, focusing on a camshaft cover of a four-stroke marine engine currently manufactured from aluminum alloy. Through numerical simulations, a commercial 30% wt GFs/PA6,6 thermoplastic composite emerges as a promising candidate, demonstrating adequate creep resistance while significantly reducing weight, processing costs, and energy consumption. The results obtained from the present study lay the foundations for the adoption of such material-based technology also in the marine engine sector despite the difficulties coming from the peculiarities of this industry.在降低成本、减轻重量和环境效益等优势的推动下，用纤维增强聚合物代替金属在汽车和航空航天工业中是一种成熟的做法。在海洋工程领域，人们对这种金属替代趋势越来越感兴趣，特别是对于船舶发动机的非结构部件，这些部件可以通过采用适当的纤维增强热塑性聚合物来生产。然而，考虑到苛刻的操作环境和严格的安全标准，评估这些材料在海洋应用中的适用性需要彻底了解它们的蠕变行为。材料选择过程必须通过定制材料设计方法复杂地考虑材料对蠕变的敏感性。此外，重新设计活动应旨在利用材料的抗蠕变性能，同时确保足够的强度和简化安装程序。不幸的是，与汽车行业不同，在真实环境中对工作发动机进行创新塑料部件的测试是完全不可能的。无论是发动机制造商还是船东，都不会允许在像船舶机舱这样的脆弱环境中安装尚未通过认证的技术，从而危及他们的机器。在这种情况下，有限元模拟提供了一种有价值的工具来评估材料的蠕变性能，并在无法进行实验测量时验证所提出的设计，从而预测部件在其预期寿命内的行为。本研究旨在利用有限元分析来评估纤维增强热塑性材料的蠕变行为及其在船用发动机中的适用性，重点是目前由铝合金制造的四冲程船用发动机的凸轮轴盖。通过数值模拟，商用30%重量的GFs/ pa6,6热塑性复合材料成为一种很有前途的候选材料，在显著降低重量、加工成本和能耗的同时，具有足够的抗蠕变性能。从本研究中获得的结果为在船用发动机领域采用这种基于材料的技术奠定了基础，尽管该行业的特殊性带来了困难。Bamboo belts with variable fiber cell angles for winding applications: development of a novel manufacturing technique and assessment of performance feasibilityQin Su, Yuting Yang, Yuanhai Zhang, Wei Song, Yu Luan, Benhua Fei, Huanrong Liu, Hu Miao, Xinxin Ma, Changhua Fangdoi:10.1016/j.compositesb.2024.111806卷绕用可变纤维细胞角度竹带:一种新型制造技术的开发和性能可行性评估In response to the environmental impacts of synthetic fiber production and disposal, coupled with limitations in the existing continuous processing methods for plant fibers, this study proposed a novel manufacturing approach for preparing wide and continuous bamboo winding belts. The current application scenarios of bamboo belt winding products are limited because the reinforcement orientation cannot be optimized due to the inherent stiffness of bamboo belts, and the variety of bamboo belt types is limited. This study employed two representative types of bamboo belts: bamboo slivers and thin bamboo veneers, which had varying cross-sectional aspect ratios. Verification demonstrated that this method enabled the production of bamboo winding products with any reinforcement orientations ranging from 0 radians to radians. This addressed the challenge of optimizing reinforcement orientation in bamboo winding products and was anticipated to broaden the application of this method to other winding units with unidirectional reinforcement. Additionally, the performance feasibility of the two bamboo winding belts prepared using this method was evaluated in terms of microstructure, surface wettability, and mechanical properties. The bamboo slivers and thin bamboo veneers, with their rigid-flexible structure, hydrophilicity, and non-catastrophic fracture characteristics, enhanced their winding potential. These wide, continuous, and rigid-flexible features of the bamboo winding belts held promise for their expanded applications in bamboo winding products, thus promoting sustainable and environmentally friendly manufacturing practices.针对合成纤维生产和处理对环境的影响，以及现有植物纤维连续加工方法的局限性，本研究提出了一种制备宽连续竹缠绕带的新方法。由于竹带固有的刚度，无法优化加固方向，且竹带类型的种类有限，限制了竹带缠绕产品目前的应用场景。本研究采用了两种具有代表性的竹带:竹条和薄竹片，这两种竹带具有不同的横截面长宽比。验证表明，该方法能够生产出从0弧度到弧度范围内任何加固方向的竹缠绕产品。这解决了优化竹缠绕产品中钢筋取向的挑战，并有望将该方法应用于其他单向加固的缠绕装置。此外，还从微观结构、表面润湿性和力学性能等方面评价了用该方法制备的两种竹缠绕带的性能可行性。竹条和薄竹片具有刚柔结构、亲水性和非灾难性断裂等特点，增强了其缠绕势。竹缠绕带的这些宽、连续、刚柔的特点为其在竹缠绕产品中的扩展应用带来了希望，从而促进了可持续和环保的制造实践。Composites Science and TechnologyLayer-by-layer assembled aramid nanofiber/MXene aerogel: Exceptional resistance to extreme temperatures and robust anisotropy for advanced applicationsChanghua Yang, Pan He, Wenyan Wang, Rui Han, Hengtong Zhang, Min Nie, Yuan Liudoi:10.1016/j.compscitech.2024.110833 一层一层组装的芳纶纳米纤维/MXene气凝胶:对极端温度的优异耐受性和强大的各向异性，适用于高级应用Aerogels are characterized with unique morphology and physical properties, thus are serving as essential elements in advanced applications. Nowadays, the delicate intelligent devices are frequently exposed in harsh environments, leading to multiple issues during application of functional aerogels including the limited resistance to extreme temperatures, requiring encapsulation prior to usage, and accumulation of Joule heat. In this study, we fabricated a multilayered aramid nanofiber (ANF)/MXene aerogel with the layer-by-layer stacking ANF and ANF/MXene layers. Attributing to the multilayered and porous structure, the aerogel displayed proper EMI shielding performance which maintained stable in harsh environments of excessive high temperature (200 °C) and low temperature (−196 °C). More importantly, obvious anisotropy in electrical conductivity (∼8 orders of magnitude) and thermal insulation (ΔT = 32 °C) was obtained along the in-plane and out-of-plane directions. As two demonstrations of potential applications, the sensing performance and thermal insulating property of the ANF/MXene aerogel was displayed. Inspiringly, the aerogel sensor exhibited significant durability and notable sensitivity to different deformations. Also, the aerogel displayed rapid heat dissipation along the in-plane direction while efficient thermal insulation along the out-of-plane direction, thus, can be applied in thermal management to protect the electronic devices. Therefore, the as-prepared ANF/MXene aerogel can serve as EMI shielding parts, encapsulation-free flexible electronics as compression sensor and anisotropic thermal insulator, which has great potential in the application of intelligent devices.气凝胶具有独特的形态和物理性质，因此在先进的应用中是必不可少的元素。如今，精密的智能设备经常暴露在恶劣的环境中，导致功能气凝胶在应用过程中存在多种问题，包括对极端温度的耐受性有限，使用前需要封装，焦耳热积累。在这项研究中，我们制备了一种多层芳纶纳米纤维(ANF)/MXene气凝胶，并将ANF和ANF/MXene层逐层堆叠。由于多层多孔结构，气凝胶具有良好的电磁干扰屏蔽性能，在超高温(200°C)和低温(- 196°C)的恶劣环境下均能保持稳定。更重要的是，电导率(~ 8个数量级)和绝热(ΔT = 32°C)沿面内和面外方向具有明显的各向异性。作为潜在应用的两个演示，展示了ANF/MXene气凝胶的传感性能和隔热性能。令人鼓舞的是，气凝胶传感器表现出显著的耐久性和对不同变形的显著敏感性。同时，气凝胶在面内方向上具有快速的散热性能，在面外方向上具有高效的隔热性能，可用于热管理，保护电子器件。因此，制备的ANF/MXene气凝胶可作为电磁干扰屏蔽件，无封装柔性电子器件作为压缩传感器和各向异性绝缘体，在智能设备的应用中具有很大的潜力。MXene grafted porous carbon cloth with alumina for high thermal conductivity and EMI shielding effectWondu Lee, Munho Kim, Jooheon Kimdoi:10.1016/j.compscitech.2024.110834 氧化铝接枝MXene多孔炭布具有高导热性和电磁干扰屏蔽效果Thermal interface material (TIM) has a great potential for efficient heat management and safety of electronic devices. However, achieving high performance polymer-based TIM is still challenging because of its intrinsic thermal conductivity and weak mechanical properties. In particular, electromagnetic interference shielding effect (EMI SE) of polymer-based composites has a great attraction according to electronic devices have become ubiquitous, playing integral roles in everyday life in our increasingly interconnected world. Herein, a porous carbon cloth (CC) for use as a continuous thermally and electrically conductive template is prepared via a freeze-casting method, after which mxene (MX) is chemically grafted onto the CC surface. Then, the as-prepared MX-CC is used along with alumina (AO) to fill a poly vinyl alcohol (PVA) matrix in order to fabricate a thermally conductive film with electromagnetic interference (EMI) shielding properties. The resultant composite demonstrates remarkable characteristics, including an excellent EMI shielding effect of 28 dB, substantial tensile strength of 19 MPa, and impressive out of plane thermal conductivity (3.98 W/mK). When applied to a light-emitting diode (LED), the PVA/MX-CC/AO composite effectively manages heat, thereby resulting in a 49 °C reduction in the operating temperature. Therefore, the composites developed herein hold great promise for improving thermal management in electronic devices.热界面材料在电子器件的高效热管理和安全性方面具有巨大的潜力。然而，由于其固有的导热性和较弱的机械性能，实现高性能聚合物基TIM仍然具有挑战性。特别是聚合物基复合材料的电磁干扰屏蔽效应(EMI SE)具有很大的吸引力，因为电子设备已经无处不在，在我们日益互联的世界中扮演着日常生活中不可或缺的角色。本发明通过冷冻浇铸法制备多孔碳布(CC)作为连续导热和导电模板，然后将mxene (MX)化学接枝到CC表面。然后，将制备好的MX-CC与氧化铝(AO)一起填充聚乙烯醇(PVA)基体，以制备具有电磁干扰(EMI)屏蔽性能的导热膜。合成的复合材料具有优异的性能，包括28 dB的电磁干扰屏蔽效果，19 MPa的抗拉强度，以及令人印象深刻的面外导热系数(3.98 W/mK)。当应用于发光二极管(LED)时，PVA/MX-CC/AO复合材料有效地管理热量，从而导致工作温度降低49°C。因此，在此开发的复合材料在改善电子器件的热管理方面具有很大的希望。Revealing the failure mechanism of 2D triaxially braided composites under off-axial tension through mesoscale simulationsYinglong Cai, Zhenqiang Zhao, Peng Liu, Jun Xing, Chao Zhangdoi:10.1016/j.compscitech.2024.110838 通过中尺度模拟揭示了二维三轴编织复合材料在离轴拉伸作用下的破坏机理The external load angle is known to have a significant influence on the mechanical behavior of two-dimensional triaxially braided composites (2DTBCs). However, the experimental data for 2DTBCs under off-axial loading provide limited information for understanding the failure mechanisms. In this study, a comprehensive mesoscale finite element (FE) model for simulating 2DTBC specimens was established to evaluate the mechanical responses and damage characteristics when off-axial tensile loads are applied. The FE model effectively captured the mechanical response at five distinct angles (0°, 30°, 45°, 60°, and 90°) and revealed the evolving patterns of failure behavior, damage morphology, and out-of-plane deformation mechanisms corresponding to the different loading angles. The findings indicate that, when the external load aligns with the axial fiber bundle direction, the primary failure mechanism involves the fracture of load-bearing fiber bundles. In contrast, deviations from the axial loading direction resulted in failure that was primarily due to the undulation of the bias fiber bundles, resulting in a loading angle–dependent warping at the edge of the specimen due to local shear stress concentration. The findings of this study provide valuable insights that can inform the design of structures with improved application.外载荷角对二维三轴编织复合材料(2dtbc)的力学性能影响很大。然而，离轴载荷作用下2dtbc的实验数据对理解其破坏机制提供的信息有限。在本研究中，建立了模拟2DTBC试件的综合中尺度有限元(FE)模型，以评估施加离轴拉伸载荷时的力学响应和损伤特征。该模型有效地捕捉了5个不同角度(0°、30°、45°、60°和90°)下的力学响应，揭示了不同加载角度下的破坏行为、损伤形态和面外变形机制的演化规律。结果表明，当外载荷方向与纤维束轴向一致时，主要破坏机制为承重纤维束断裂;相反，偏离轴向加载方向导致破坏，这主要是由于偏压纤维束的波动，导致试样边缘由于局部剪应力集中而产生加载角度相关的翘曲。本研究的发现提供了有价值的见解，可以告知结构的设计与改进的应用。Dodging reality, striking the virtual: An undulating strategy for effectively enhancing CF/PEEK interfacial adhesion!Yining Wang, Mingguang Zhang, Cijian Zhang, Qicong Yao, Wenhui Zhou, Yu Deng, Qian Liu, Shouhai Zhang, Zhihuan Weng, Cheng Liu, Xigao Jian, Yousi Chendoi:10.1016/j.compscitech.2024.110839 躲避现实，冲击虚拟:一种有效增强CF/PEEK界面附着力的波动策略!The design of carbon fiber (CF)-reinforced polyetheretherketone (PEEK) composite materials with suitable interfaces has consistently been challenging. In this study, we sulfonated poly (phthalazinone ether sulfone ketone) (PPESK) and PEEK to prepare water-soluble SPPESK and SPEEK. Subsequently, we prepared a water-soluble sizing agent (SPPESK/SPEEK) via a straightforward blending process. This sizing agent tended to accumulate randomly on the surfaces of CFs, forming a thin film with a heterogeneous structure in the nanoscale. At the molding temperature of the composite material, the two components on the fiber surface exhibited different rheological behaviors, with PEEK preferentially infiltrating the SPEEK region, forming strong molecular entanglements. Meanwhile, the SPPESK region provided a rigid supportive structure, offering the potential for the mechanical interlocking of PEEK in the interface layer. The performance of the prepared composite materials was significantly enhanced, with their interlaminar shear strength and flexural strength reaching 87.1 MPa and 975.8 MPa, respectively. With respect to those of commercial fiber-reinforced PEEK composites, an 89.8 % increase in interlaminar shear strength and a 79.39 % increase in flexural strength were observed. This interface reinforcement mechanism presents a universally applicable strategy for the future development of fiber-reinforced composite materials.设计具有合适界面的碳纤维(CF)增强聚醚醚酮(PEEK)复合材料一直是一个挑战。在本研究中，我们将聚酞嗪酮醚砜酮(PPESK)和PEEK磺化，制备了水溶性的SPPESK和SPEEK。随后，我们通过简单的混合工艺制备了一种水溶性施胶剂(SPPESK/SPEEK)。在纳米尺度上，该施胶剂倾向于随机积聚在碳纤维表面，形成具有非均相结构的薄膜。在复合材料成型温度下，纤维表面的两种组分表现出不同的流变行为，PEEK优先渗入SPEEK区域，形成强烈的分子缠结。同时，SPPESK区域提供了刚性支撑结构，为PEEK在界面层中的机械互锁提供了潜力。复合材料的层间抗剪强度和抗折强度分别达到87.1 MPa和975.8 MPa，复合材料的性能得到了显著提高。与商用纤维增强PEEK复合材料相比，层间剪切强度提高了89.8%，弯曲强度提高了79.39%。这种界面增强机制为纤维增强复合材料的未来发展提供了一种普遍适用的策略。Protective Coating Performance for Structural Integrity of Polymer Composites in Fire: Novel Bench Scale Instrument Design and Coupon Level TestXiang Ao, Junchen Xiao, Gloria Guerrero Muñoz, Carlos González, De-Yi Wangdoi:10.1016/j.compscitech.2024.110830 火灾中聚合物复合材料结构完整性防护涂层性能:新型台架仪器设计与试验The loss of structural integrity of fiber-reinforced polymer composites (FRPs) when set on fire poses a great threat for the safety of occupants and property, which can be alleviated by introducing fire protective methods. The fire-protective polymeric coating has shown great potential in reducing fire hazards of FRPs and preventing loss of post-fire mechanical properties, but it has seldom been proven to have a protective effect under simultaneous loading and fire damage on a coupon level using a lab scale instrument. In this work, a machine which can be mounted on the widely acknowledged cone calorimeter (CCT) was designed and fabricated with details provided. Two types of laminate were prepared to be subjected to a static axial or off-axial load while set ignited and burned. Results showed that the protective polymeric coating delayed coated coupons for mechanical failure time by more than 190% compared to coupons without any coating. With this instrument being universally adaptable to various types of CCT, it provided meaningful information to the materials design process of fire-safe FRPs.纤维增强聚合物复合材料(frp)在着火时结构完整性的丧失对人身和财产安全造成了极大的威胁，通过引入防火措施可以缓解这一威胁。防火聚合物涂层在减少frp的火灾危险和防止火灾后机械性能损失方面显示出巨大的潜力，但在实验室规模的仪器上，它很少被证明在同时加载和火灾破坏的水平上具有保护作用。在这项工作中，设计和制造了一个可以安装在广泛认可的锥量热计(CCT)上的机器，并提供了细节。制备了两种类型的层压板，使其在设定点燃和燃烧时承受静态轴向或离轴向载荷。结果表明，与未涂覆涂层相比，涂覆聚合物保护层可使涂覆后的试件机械失效时间延长190%以上。该仪器具有普遍适用性，为防火frp材料设计过程提供了有意义的信息。Self-healing and thermal transport behavior in catalytic vitrimer-graphene compositeMd. Sherajul Islam, Jonghoon Lee, Vikas Varshney, Dhriti Nepal, Ajit K. Roydoi:10.1016/j.compscitech.2024.110835 催化玻璃体-石墨烯复合材料的自愈和热输运行为Vitrimers are a distinct category of polymers that could conduct dynamic cross-linking in response to temperature stimuli. In this work, using a molecular dynamics simulation model, we explore self-healing and the thermal transport behavior of vitrimer-graphene composites to overcome its inherent slow self-healing process. The temperature-dependent reversible cross-link mechanisms, which possess the capacity to dynamically modify the mechanical properties of these substances, are studied by explicitly integrating the temperature-dependent reaction probabilities. This modeling approach efficiently predict the changes in the mechanical properties of vitrimers when undergoing temperature cycling both above and below the topological freezing point, as well as the damage healing and subsequent recuperation of mechanical behaviors. The heat transport behavior of the graphene-vitrimer composite is investigated using non-equilibrium molecular dynamics in conjunction with self-healing models. The thermal conductivity of vitrimer-graphene composites, calculated by including a bilayer graphene sheet with varied flake size and interlayer spacings, exhibits a considerable enhancement as compared to standalone vitrimers. Notably, the thermal conductivity is subject to change when the separation distance changes. These results shed light on the self-healing and heat transmission in vitrimer and open the door to possible applications in several fields, including electronics, energy efficiency, aerospace, and materials research.玻璃体是一类独特的聚合物，可以在温度刺 激下进行动态交联。在这项工作中，我们利用分子动力学模拟模型，探索了玻璃体-石墨烯复合材料的自修复和热传输行为，以克服其固有的缓慢自修复过程。通过显式积分温度相关反应概率，研究了具有动态改变这些物质力学性能能力的温度相关可逆交联机制。这种建模方法有效地预测了玻璃聚合体在拓扑冰点以上和以下温度循环时力学性能的变化，以及损伤愈合和随后的力学行为恢复。利用非平衡分子动力学和自愈模型研究了石墨烯-玻璃体复合材料的热传递行为。玻璃体-石墨烯复合材料的导热性，通过包含具有不同薄片大小和层间间距的双层石墨烯片来计算，与单独的玻璃体相比，表现出相当大的增强。值得注意的是，导热系数随分离距离的变化而变化。这些结果揭示了玻璃体的自我修复和热传输，并为电子、能源效率、航空航天和材料研究等多个领域的潜在应用打开了大门。A generalized equivalent circuit model for composite metamaterial absorbers: From isotropic to anisotropic substrateDi Li, Jing Zhou, Yingguang Li, Weiwei Xu, Shuting Liu, Xiaozhong Haodoi:10.1016/j.compscitech.2024.110832 复合材料吸波器的广义等效电路模型:从各向同性基底到各向异性基底Recently, metamaterial absorbers (MAs) with a multi-layered anisotropic substrate have received significant attention due to their huge potential for application in major engineering fields like aircraft stealthing, electromagnetic sensing, and materials processing, etc. However, the working mechanism of this type of structural materials has not been well-understood yet, as the classical equivalent circuit model was only proposed to describe the conventional overall isotropic metal-substrate MAs. In this paper, for the first time, a generalized equivalent circuit model that considering the anisotropy of the multi-layered substrate is constructed, based on new findings about the unique distribution of the induced current inside the MA with a carbon fiber reinforced polymer (CFRP) composite substrate – a typical multi-layered anisotropic laminate. The effectiveness of the generalized analytical model is validated by predicting the structure-performance relationship of the CFRP-substrate MA, which is in excellent agreement with numerical simulation results based on Maxwell’s equations. Experimental cases have also been conducted to demonstrate the strong power of this model in inverse design of several tunable MAs. Through the above research, the scope of the equivalent circuit modelling has been greatly broadened, which can help to design a series of MAs with more extreme performance in future.近年来，具有多层各向异性衬底的超材料吸波材料因其在飞机隐身、电磁传感、材料加工等重大工程领域的巨大应用潜力而备受关注。然而，这类结构材料的工作机制尚未得到很好的理解，因为经典的等效电路模型仅用于描述传统的整体各向同性金属-衬底MAs。本文基于对碳纤维增强聚合物(CFRP)复合材料衬底-一种典型的多层各向异性层合板-内部感应电流独特分布的新发现，首次建立了考虑多层衬底各向异性的广义等效电路模型。通过对cfrp -衬底复合材料结构性能关系的预测，验证了广义解析模型的有效性，该模型与基于麦克斯韦方程的数值模拟结果吻合良好。实验证明了该模型在若干可调谐MAs反设计中的强大功能。通过以上研究，大大拓宽了等效电路建模的范围，有助于未来设计一系列性能更极端的MAs。来源：复合材料力学仿真Composites FEM
