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【新文速递】2024年2月25日复合材料SCI期刊最新文章

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今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 6 篇,Composites Science and Technology 2 篇

Composite Structures

Experimental study of bonded, bolted, and hybrid bonded-bolted single lap shear joints with woven CFRP adherends

Mahdi Damghani, Mohammad Saad Khan, Gary A. Atkinson

doi:10.1016/j.compstruct.2024.117989

带编织 CFRP 粘接剂的粘接、螺栓和混合粘接-螺栓单搭接剪力连接的实验研究

This paper presents an extensive experimental performance study of bonded joints (BJs), only bolted joints (OBJs) and hybrid bonded-bolted joints (HJs). For each joint type, three test configurations are considered: namely, short, medium and long overlap lengths. In each case, the adherends comprise quasi-isotropic twill woven CFRP. For each joint type/overlap length combination, three specimens are tested for statistical representation. HJs demonstrate 1.4, 1.5 and 1.5 times higher failure load and 1.5, 1.6 and 1.9 times higher stiffness than OBJs, for short, medium and long overlap, respectively. In all test cases, HJs outperform BJs except for short overlaps where BJs outperform both HJs and OBJs. OBJs perform poorly in terms of failure load and Hooke’s stiffness. Nevertheless, due to bearing deformation at bolt hole locations, OBJs experience higher failure displacements than BJs and HJs leading to a desirable energy absorption mechanism compared to HJs and BJs. This is thanks to the bearing failure mode of the joint despite much lower failure load in OBJs. It was found that increasing the overlap length generally benefits BJs. However, for medium length overlap specifically, HJs show better performance than BJs. Stress–strain behaviours show a linear behaviour for all test groups with significant joint rotation for OBJs compared to BJs and HJs. Failure mechanism studies presented in the paper show that BJs fail in cohesive failure mode for all test groups. OBJs fail in bearing mode, which is followed by net tension failure. OBJs experience matrix cracking and delamination at bolt hole locations. On the contrary, HJs experience considerably less bearing failure at bolt holes due to the load bearing contribution from the adhesive.

本文对粘接接头(BJ)、纯螺栓接头(OBJ)和粘接-螺栓混合接头(HJ)进行了广泛的性能实验研究。每种接头类型都考虑了三种测试配置:即短、中和长重叠长度。在每种情况下,粘合剂都由准各向同性的斜纹编织 CFRP 组成。对于每种连接类型/重叠长度组合,都测试了三个试样以进行统计。在短、中、长重叠情况下,HJ 的破坏载荷分别比 OBJ 高 1.4、1.5 和 1.5 倍,刚度分别比 OBJ 高 1.5、1.6 和 1.9 倍。在所有测试情况下,HJ 均优于 BJ,但在短重叠情况下,BJ 优于 HJ 和 OBJ。OBJ 在破坏载荷和胡克刚度方面表现较差。然而,由于螺栓孔位置的轴承变形,OBJ 比 BJ 和 HJ 具有更高的失效位移,因此与 HJ 和 BJ 相比,OBJ 具有更理想的能量吸收机制。这要归功于接头的轴承失效模式,尽管 OBJ 的失效载荷要低得多。研究发现,增加重叠长度通常对 BJ 有利。然而,具体到中等长度的重叠,HJ 的性能要优于 BJ。应力-应变行为在所有测试组中都表现为线性行为,与 BJ 和 HJ 相比,OBJ 的关节旋转明显。论文中的失效机理研究表明,在所有测试组中,BJ 均以内聚失效模式失效。OBJ 以轴承模式失效,随后是净拉力失效。OBJ 在螺栓孔位置出现基质开裂和分层。相反,由于粘合剂的承载作用,HJ 在螺栓孔处发生的承载失效要少得多。


Complex CFRP damage detection with dual multiscale 1DCNNs and self-selective fusion technique of guided waves

Yunlai Liao, Yuan Huang, Yihan Wang, Minhuang Wu, Fanghong Zhang, Xinlin Qing

doi:10.1016/j.compstruct.2024.117993

利用双多尺度 1DCNN 和导波自选择融合技术检测复杂 CFRP 损伤

This article presents an innovative damage detection method, named DMS1DCNNs, based on new dual multiscale one-dimensional convolutional neural networks (MS1DCNNs) and a novel self-selective fusion technique for damage localization and quantification in complex carbon fiber reinforced plastic (CFRP) structures. Firstly, a new multiscale piecewise aggregate approximation algorithm (MIPA) is proposed to compress the guided wave (GW) signals and extract damage features at various time scales. Considering that signals from low-information sensing paths may interfere with the diagnostic performance of the model, a new method for self-selective fusion of GW sensing paths is proposed. This method can automatically fuse paths with more damage information and remove paths with less damage information. Then, a new DMS1DCNNs model is presented, capable of obtaining multiscale damage features in GW signals from both data and network levels. The model takes GW data as input and employs regression methods for direct prediction of the damage location and size. Finally, the method is validated using the GW testbed, and the mean relative error of location on complex CFRP is 8.32 % and the mean absolute error of quantification is 1.20 mm, superior to other state-of-the-art methods.

本文基于新型双多尺度一维卷积神经网络(MS1DCNNs)和新型自选择融合技术,提出了一种创新的损伤检测方法(DMS1DCNNs),用于复杂碳纤维增强塑料(CFRP)结构的损伤定位和量化。首先,提出了一种新的多尺度片状集 合近似算法(MIPA),用于压缩导波(GW)信号并提取不同时间尺度的损伤特征。考虑到来自低信息传感路径的信号可能会干扰模型的诊断性能,提出了一种自选择融合导波传感路径的新方法。这种方法可以自动融合损伤信息较多的路径,并移除损伤信息较少的路径。然后,提出了一种新的 DMS1DCNNs 模型,该模型能够从数据和网络两个层面获取全球大气气象数据信号中的多尺度损伤特征。该模型以 GW 数据为输入,采用回归方法直接预测损伤位置和大小。最后,该方法通过 GW 试验台进行了验证,在复杂 CFRP 上的定位平均相对误差为 8.32 %,量化平均绝对误差为 1.20 mm,优于其他最先进的方法。


Prediction of transverse permeability in representative volume elements with closely arranged fibers through the application of delaunay-triangulation and electrical-circuit analogy

Hyeonseong Jo, Sangyoon Bae, Hyunsoo Hong, Wonvin Kim, Seong Su Kim

doi:10.1016/j.compstruct.2024.117984

通过应用德劳内三角测量法和电路类比法预测具有紧密排列纤维的代表性体积元素中的横向渗透率

The distribution of fibers in composite manufacturing significantly affects fiber bundle permeability, a crucial factor for resin impregnation and void formation, which determines final product quality. However, as the industry increasingly seeks composite materials characterized by high fiber volume fractions, the existing numerical analysis methodologies employed for predicting permeability require a considerable computational cost. In this study, the permeability prediction model was developed using a fluid domain simplification technique based on Delaunay triangulation. The inter-fiber flow was approximated using a lubrication model, and continuity was ensured using a circuit analogy. This model can explain stochastic permeability characteristics according to fiber distribution and accurately predicts the permeability regardless of the distance between fibers. Additionally, compared to existing computational fluid dynamics simulations, it achieved an incredible accuracy of 97.74% and reduced computational costs by an average of 1,700 times.

纤维在复合材料生产中的分布对纤维束的渗透性有很大影响,而纤维束的渗透性是树脂浸渍和空隙形成的关键因素,决定着最终产品的质量。然而,随着业界对高纤维体积分数复合材料的需求与日俱增,用于预测渗透性的现有数值分析方法需要相当高的计算成本。本研究采用基于 Delaunay 三角剖分的流体域简化技术开发了渗透性预测模型。纤维间的流动使用润滑模型进行近似,并使用电路类比确保连续性。该模型可根据纤维分布解释随机渗透特性,并准确预测渗透率,而不受纤维间距的影响。此外,与现有的计算流体动力学模拟相比,该模型的精确度达到了惊人的 97.74%,计算成本平均降低了 1,700 倍。


Characterization and prediction of tensile properties of carbon fiber-reinforced thermoplastics composed of hybrid short carbon fiber/PA6 fiber nonwoven mats

Qian Gao, Yi Wan, Haowen Wei, Jun Takahashi

doi:10.1016/j.compstruct.2024.117996

由混合短碳纤维/PA6 纤维无纺毡组成的碳纤维增强热塑性塑料的拉伸特性表征与预测

Hybrid carbon fiber/resin fiber nonwoven mats are considered as a highly promising application of recycled carbon fibers due to their low cost and simple synthesis process. However, the mechanical properties of hybrid nonwoven mats are subject to uncertainties due to nonuniformity of fiber orientations during production procedures, which restricts their use in structural components. This study investigates the characteristics of various types of hybrid nonwoven mats with different volume fractions and fiber orientation distributions. Notably, the investigation yields noteworthy tensile properties, exemplified by a tensile strength of 367.20 MPa and a stiffness of 32.85 GPa, when the volume fraction is 28.9%. Tensile properties of the hybrid nonwoven mats and their fluctuations are then analyzed through statistical analyses. A three-dimensional microstructure-based fiber network model is established using the Monte Carlo method to represent the statistical and stochastic properties of the material. Furthermore, a prediction method of tensile properties based on microstructural properties in the model is proposed, which shows good agreement with all experimental results for adjustments of the volume fraction of carbon fibers, distribution of fiber lengths, and anisotropy of the materials, significantly reducing the experimental burden for optimization research. The tensile characteristics of composites are reliably anticipated with a nominal error margin below 10%. Additionally, this prediction method enables the prediction of scatter and stable standard deviation, making it possible to apply hybrid nonwoven mats in recycling and industrial processes.

碳纤维/树脂纤维混合非织造毡因其低成本和简单的合成工艺而被认为是再生碳纤维的一种极具前景的应用。然而,由于生产过程中纤维取向的不均匀性,混合非织造毡的机械性能存在不确定性,限制了其在结构部件中的应用。本研究调查了具有不同体积分数和纤维取向分布的各类混合无纺布毡的特性。值得注意的是,这项研究获得了显著的拉伸特性,例如,当体积分数为 28.9% 时,拉伸强度为 367.20 兆帕,刚度为 32.85 千兆帕。然后通过统计分析分析了混合无纺毡的拉伸性能及其波动。使用蒙特卡罗方法建立了基于三维微结构的纤维网模型,以表示材料的统计和随机特性。此外,还提出了一种基于模型中微观结构特性的拉伸特性预测方法,该方法在调整碳纤维体积分数、纤维长度分布和材料各向异性时与所有实验结果显示出良好的一致性,大大减轻了优化研究的实验负担。复合材料的拉伸特性得到了可靠的预测,误差率低于 10%。此外,这种预测方法还能预测散度和稳定的标准偏差,从而使混合无纺毡在回收和工业流程中的应用成为可能。


Composites Part A: Applied Science and Manufacturing

Studies on 8.4 W/m·K thermally conductive silicone rubber with high compressibility, high electrical insulation, high thermal reliability, and low cost

Jianping Liu, Zhiming Fang, Chenlu Bao.

doi:10.1016/j.compositesa.2024.108100

研究具有高压缩性、高电绝缘性、高热稳定性和低成本的 8.4 W/m-K 导热硅橡胶

Thermally conductive silicone rubber (TCSR) has been widely used to enhance heat dissipation in electronics and energy storage devices. Currently, it is a challenge to produce TCSR which combines high thermal conductivity, high compressibility, high thermal reliability, high electrical insulation, and low cost. Here, we report a state-of-the-art TCSR which achieves such a combination. Owing to the optimized alumina gradation, the loading level of alumina in the TCSR reaches 96 wt%. The TCSR reaches a high and isotropic thermal conductivity of 8.4 W/m·K, a high compression ratio of 48 % (under a pressure of 6 psi or 42.4 kPa), and a high dielectric strength (>6 kV/mm). After heating at 180 °C for 100 h, little oil bleeding is observed. More importantly, these properties remain stable (variation < 10 %) after 2000 h of thermal aging at 135 °C, indicating high thermal reliability.

导热硅橡胶(TCSR)已被广泛用于提高电子设备和储能设备的散热性能。目前,生产兼具高导热性、高可压缩性、高热稳定性、高电绝缘性和低成本的导热硅橡胶是一项挑战。在此,我们报告了一种最先进的 TCSR,它实现了这样的组合。由于优化了氧化铝级配,TCSR 中的氧化铝含量达到 96 wt%。这种 TCSR 的各向同性热导率高达 8.4 W/m-K,压缩比高达 48%(压力为 6 psi 或 42.4 kPa),介电强度也很高(大于 6 kV/mm)。在 180 °C 下加热 100 小时后,几乎没有渗油现象。更重要的是,这些特性在 135 °C 下经过 2000 小时的热老化后仍然保持稳定(变化 < 10 %),表明热可靠性很高。


Composites Part B: Engineering

Electronic metal-support interaction-induced space charge polarization for boosting photoelectrochemical water splitting

Chengming Zhang, Jianli Chen, Meng Wang, Haibao Zhu, Jun Ma, Huanhuan Wu, Huihui Ding, Xiaolong Fang, Fazhi Xie, Zhi Tang, Xiaoli Zhao, Yi Ding, Hewen Liu, Xiufang Wang

doi:10.1016/j.compositesb.2024.111327

 

电子金属-支撑物相互作用诱导的空间电荷极化促进光电化学水分离

Overcoming the inherent transportation of charge constraint of the photoanode has been critical for seeking feasible photoelectrochemical (PEC) water splitting. Here, we propose to utilize electron metal-support interactions (EMSI) between Cu nanoparticles (NPs) and N-C support for modifying the electronic structure of CuNPs-N-C/SnS2 photoanode and analyze the impact of EMSI on the process of PEC water splitting. The combination of detailed theoretical simulation calculations and comprehensive characterizations indicates that the charge imbalance induced by EMSI within the CuNPs-N-C and SnS2 interfaces results in an enhanced interfacial polarized electric field and boosts the separation of photo-induced carriers at the CuNPs-N-C and SnS2 interfaces. The optimal CuNPs-N-C/SnS2 photoanode displays remarkable properties with a considerably upgraded photocurrent of 2.33 mA cm−2 at 1.23 VRHE, which is 6.30 beyond the value of SnS2 (0.37 mA cm−2). This work paves a way to developing high-performance photoanodes for efficient PEC water splitting.

克服光阳极固有的电荷传输限制对于寻求可行的光电化学(PEC)水分离至关重要。在此,我们提出利用铜纳米粒子(NPs)与 N-C 支持物之间的电子金属-支持物相互作用(EMSI)来改变 CuNPs-N-C/SnS2 光阳极的电子结构,并分析 EMSI 对 PEC 水分离过程的影响。详细的理论模拟计算和全面的表征相结合表明,EMSI 在 CuNPs-N-C 和 SnS2 界面上引起的电荷不平衡导致界面极化电场增强,并促进了光诱导载流子在 CuNPs-N-C 和 SnS2 界面上的分离。最佳的 CuNPs-N-C/SnS2 光阳极具有显著的特性,在 1.23 VRHE 下的光电流高达 2.33 mA cm-2,比 SnS2(0.37 mA cm-2)高出 6.30 倍。这项工作为开发用于高效 PEC 水分离的高性能光阳极铺平了道路。


Predicting failure in injection-moulded short-fibre subcomponents under varied environmental conditions through fracture mechanics

Yuki Fujita, Satoshi Noda, Junichi Takahashi, Emile S. Greenhalgh, Soraia Pimenta

doi:10.1016/j.compositesb.2024.111343

 

通过断裂力学预测不同环境条件下注塑短纤维子组件的失效情况

Injection-moulded short-fibre composites are lightweight materials suitable for high-volume applications; however, current simulation methods (based on failure initiation criteria) to design components using these materials cannot yet accurately predict failure. This work presents a methodology to predict failure of injection-moulded short-glass-fibre reinforced thermoplastic (IM-SFRP) composite subcomponents, based on experimentally measured properties. The material's fracture toughness was characterized by Compact Tension tests for different fibre orientations and environmental conditions. These fracture toughnesses were used as the input for cohesive zone modelling in Finite Element simulations of subcomponents representative of automotive applications, coupled with fibre orientation fields predicted by an injection-moulding process simulation. These coupled simulations presented excellent agreement with the experimental results for subcomponents both in terms of (i) the peak load (highlighting the importance of accounting for the finite fracture toughness of the material to accurately predict the ultimate failure of the subcomponents), and (ii) the pre- and post-peak sequence of failure events (verified using fractographic analyses). This work also verified the applicability of temperature-moisture equivalence, not only for material characterisation using coupons including the material's fracture toughness, but also for the mechanical response of subcomponents until final failure. The methodology demonstrated in this paper contributes to designing safer and more efficient damage-tolerant IM-SFRP components.

注塑短纤维复合材料是适合大批量应用的轻质材料;然而,目前使用这些材料设计组件的模拟方法(基于失效启动标准)还不能准确预测失效。本研究提出了一种基于实验测量属性预测注塑短玻纤增强热塑性塑料(IM-SFRP)复合材料子组件失效的方法。材料的断裂韧性是通过不同纤维取向和环境条件下的紧凑拉伸试验确定的。这些断裂韧性被用作汽车应用子部件有限元模拟中内聚区建模的输入,并与注塑成型工艺模拟预测的纤维取向场相结合。这些耦合模拟在以下两个方面与实验结果非常吻合:(i) 峰值载荷(突出了考虑材料有限断裂韧性对准确预测子部件最终失效的重要性);(ii) 失效事件的前后峰值序列(使用断裂分析进行验证)。这项工作还验证了温度-湿度等效的适用性,不仅适用于使用包括材料断裂韧性在内的试样进行材料表征,还适用于直到最终失效的子组件机械响应。本文展示的方法有助于设计更安全、更高效的 IM-SFRP 容损组件。


Quantitative ultrasonic imaging of weave structure in textile composites

Xiaoyu Yang, Mathias Kersemans, Zheng Fan

doi:10.1016/j.compositesb.2024.111310

纺织复合材料编织结构的定量超声波成像

Textile composites owe their desirable mechanical properties to the intricate fabric architecture. However, manufacturing deviations can influence these attributes, significantly affecting their mechanical performance. Thus, ensuring the quality and structural integrity of fabric architectures has become pivotal, leading to the advancement of ultrasonic non-destructive testing techniques. However, existing techniques, primarily tailored for unidirectional laminates, often struggle with weave pattern extraction, given the complex features of fabric laminates. To address this gap, a pulse-echo ultrasound coupled to a 2D analytic-signal analysis is proposed. The 2D analytic-signal methodology autonomously discerns the complex ultrasound features from fabric laminates, streamlining weave pattern analysis. The study showcases ply-by-ply reconstruction of local weave patterns of fabric laminates with nominal layups of [#(0/90)]8 and [#(+45/−45 )#(0/90)]5s, respectively. The efficacy of the methodology is ascertained through quantitative metrics, highlighting its innovative potential for through-depth extraction of local weave patterns in a swift and automated manner.

纺织复合材料之所以具有理想的机械性能,是因为其复杂的织物结构。然而,制造过程中的偏差会影响这些属性,从而严重影响其机械性能。因此,确保织物结构的质量和结构完整性变得至关重要,从而推动了超声波无损检测技术的发展。然而,鉴于织物层压板的复杂特性,主要针对单向层压板量身定制的现有技术在提取编织图案方面往往力不从心。为了弥补这一不足,我们提出了脉冲回波超声与二维分析信号分析相结合的方法。二维分析信号方法可自主识别织物层压板的复杂超声波特征,从而简化织纹分析。研究展示了逐层重建织物层压板的局部编织图案,其标称层叠分别为 [#(0/90)]8 和 [#(+45/-45 )#(0/90)]5s 。该方法的功效通过定量指标得以确定,突出了其在快速、自动地深入提取局部编织图案方面的创新潜力。


Controlled interlaminar crack initiation in thin notched laminated thermoplastic composites under impact loading: A first step towards unitary layer recovery

Awen Bruneau, Mathieu Imbert, Michael May

doi:10.1016/j.compositesb.2024.111322

冲击载荷下薄型缺口层压热塑性复合材料中受控制的层间裂纹起始:向单元层恢复迈出第一步

The recycling of composite materials is nowadays a major challenge as it is systematically associated with a downcycling due to the reduction of the fiber length. However, recent works demonstrated that the delamination-based recovery of the unitary layers of laminated structures with preserved mechanical properties is possible under dedicated loading conditions. The presented work aims at investigating this innovative process and in particular the interlaminar crack initiation from a straight notch milled in the material by using an impact loading; further crack extension to recover the complete lamina being the following step of the process. A Split Hopkinson Bar setup has been used in a Direct Impact configuration and a dedicated test setup has been implemented to impose translational and rotational kinematics to the impacted side of the tested specimens in order to enable crack initiation and propagation over a few millimeters. Imposing translational kinematics to the impacted side of the specimen has been shown to induce cracks in a reproducible manner. Numerical simulation results explain the more favorable conditions provided by the translational kinematic.

如今,复合材料的回收利用是一项重大挑战,因为纤维长度的减少会导致复合材料的回收利用率降低。然而,最近的研究表明,在特定的加载条件下,基于分层的层压结构单元层的恢复是可能的,并能保持其机械性能。本文介绍的工作旨在研究这一创新工艺,特别是通过使用冲击加载,从材料上铣出的直切口处引发层间裂纹;该工艺的下一步是进一步扩展裂纹,以恢复完整的层状结构。在直接冲击配置中使用了分体式霍普金森棒装置,并实施了专门的测试装置,对测试试样的冲击侧施加平移和旋转运动学,以实现裂纹在几毫米范围内的萌发和扩展。对试样受冲击的一侧施加平移运动学已被证明能以可重复的方式诱发裂纹。数值模拟结果解释了平移运动学提供的更有利条件。


Mechanically robust multifunctional starch films reinforced by surface-tailored nanofibrillated cellulose

Jiarong Tian, Yingqi Kong, Shaoping Qian, Zhaoyan Zhang, Yingbo Xia, Zhijie Li

doi:10.1016/j.compositesb.2024.111339

 

由表面定制的纳米纤维素增强的机械坚固的多功能淀粉薄膜

The objective of this study was to develop a transparent, mechanically robust, and fully biodegradable film made of sweet potato starch (SPS) reinforced with nanofibrillated cellulose (NFC) to serve as a potential alternative for packaging. Various surface modifications were applied to NFC using urea/NaOH (UA), oxalic acid (OA), citric acid (CA), and (3-mercaptopropyl) trimethoxysilane (MT). SPS/NFC blend was innovatively treated by ball-milling, incorporating different concentrations (2–10 wt%) of surface-modified NFC and calcium gluconate as a modifier. Interestingly, the solution-cast blend films possessed improved tensile strength, tensile modulus, crystallinity, barrier property and hydrophobicity after NFC additions. More importantly, ball-milling promoted the physical combination of starch and NFC and generated metal-organic supramolecular interaction between –OH and Ca2+. In particular, the SPS-OA/NFC6 composite film exhibited remarkable improvements in tensile strength and tensile modulus, increasing from 1.46 MPa and 6.04 MPa–13.7 MPa and 531.33 MPa, respectively, compared to the neat SPS film. The contact angle of the SPS/CA-NFC6 film was approximately 79% higher than that of the pure SPS film. Generally, the optimal NFC addition was 6 wt%. This study provides guidance for the production of a new type of starch-based material with high mechanical strength and transparency.

本研究旨在开发一种透明、机械坚固且可完全生物降解的薄膜,该薄膜由纳米纤维素(NFC)增强的甘薯淀粉(SPS)制成,可作为一种潜在的包装替代品。使用尿素/NaOH(UA)、草酸(OA)、柠檬酸(CA)和(3-巯基丙基)三甲氧基硅烷(MT)对 NFC 进行了各种表面改性。通过球磨创新性地处理了 SPS/NFC 混合物,加入了不同浓度(2-10 wt%)的表面改性 NFC 和葡萄糖酸钙作为改性剂。有趣的是,添加 NFC 后,溶液浇铸混合薄膜的拉伸强度、拉伸模量、结晶度、阻隔性和疏水性都得到了改善。更重要的是,球磨促进了淀粉和 NFC 的物理结合,并在 -OH 和 Ca2+ 之间产生了金属有机超分子相互作用。与纯 SPS 薄膜相比,SPS-OA/NFC6 复合薄膜的拉伸强度和拉伸模量有了显著提高,分别从 1.46 兆帕和 6.04 兆帕提高到 13.7 兆帕和 531.33 兆帕。SPS/CA-NFC6 薄膜的接触角比纯 SPS 薄膜高出约 79%。一般来说,最佳的 NFC 添加量为 6 wt%。这项研究为生产具有高机械强度和透明度的新型淀粉基材料提供了指导。


A novel 3D topological metamaterial for controllability of polarization-dependent multilayer elastic waves

Guifeng Wang, Tian Wang, Zhenyu Chen, Zhiwen Zhu, C.W. Lim

doi:10.1016/j.compositesb.2024.111341

 

用于控制偏振相关多层弹性波的新型三维拓扑超材料

The achievement of high-quality wave manipulation and energy concentration has always been considered as state-of-the-art technologies, especially for integrated photonics, acoustics, and mechanics. The exploration of the topological phase of matter provides abundant design tools for robust waveguiding that is immune to backscattering at small defects and sharp bends. Recent research has extended the elastic wave manipulation from 2D edge waveguiding to 3D planar waveguiding. However, most of them are limited to single-mode and single-frequency wave propagation along the designed plane. This paper introduces a novel 3D topological metamaterial structure whose geometrical parameters are specifically configured to obtain dual-mode topological states at distinct frequencies. Parametric studies are presented to demonstrate the controllability of bandgaps and to provide a design principle for preventing the effects of unwanted modes. Topological interface modes with either high group velocity or near-zero group velocity along the z direction are found. Full-scale finite element simulations are presented to uncover the elastic wave propagation behavior. The interesting layer-locked and layer-unlocked waveguiding based on excitation polarization and frequency for both straight path and zig-zag path are demonstrated. The outcomes of this work suggest abundant potential applications related to elastic wave control such as wave filters, energy harvesters, mechanical computers, and the like. This work may also help inspire future research on more complex and sophisticated multi-mode waveguiding in 3D spaces.

实现高质量的波操纵和能量集中一直被认为是最先进的技术,尤其是在集成光子学、声学和力学方面。对物质拓扑相的探索提供了丰富的设计工具,用于设计坚固耐用的波导,这种波导在小缺陷和急弯处不会产生反向散射。最近的研究已将弹性波操纵从二维边缘波导扩展到三维平面波导。然而,这些研究大多局限于单模和单频波沿设计平面的传播。本文介绍了一种新型三维拓扑超材料结构,其几何参数经过专门配置,可在不同频率下获得双模拓扑状态。本文介绍了参数研究,以证明带隙的可控性,并提供了防止不需要的模式影响的设计原则。研究发现拓扑界面模式沿 Z 方向具有高群速度或接近零的群速度。全尺寸有限元模拟揭示了弹性波的传播行为。基于激发极化和频率,演示了直行和之字形路径上有趣的层锁定和层解锁波导。这项工作的成果表明,与弹性波控制相关的应用潜力巨大,例如波滤波器、能量收集器、机械计算机等。这项工作还有助于启发未来在三维空间中开展更复杂、更精密的多模波导研究。


Composites Science and Technology

Coupling relationship between molecule structure at silica/silicone gel interfaces and ionic conductivity in polymer composites

Ying Lin, Liye Dong, Chuanle Heng, Kai Chen, Yuhao Liu

doi:10.1016/j.compscitech.2024.110507

 

二氧化硅/硅凝胶界面分子结构与聚合物复合材料离子传导性之间的耦合关系

Herein, the coupling relationship between molecule structure and ion conductivity in silica filled silicone gel are established. Based on the broadband dielectric spectrum, the concentration of ion charges and ions diffusion coefficients, two key roles for ion conductivity, are calculated. The concentration of ion charges is increased by about four orders of magnitude after the addition of silica. Because of the more short-length chains conformations and more amorphous regions at interfaces, the chains at interfaces are easier to rearrange with higher relaxation frequency, which enhances the ions diffusion process and contributes to negative decoupling exponents between the interface molecule relaxations and ion diffusion coefficients in silicone gel composites. With the increase of fumed silica loading, the ionic conductivity increases first and decreases owing to percolation phenomenon about silica dispersion. Meanwhile, decoupling exponents of the interface molecules are closer to 0. Our findings deepen the understanding how the interface structures act on ions conductivity in insulating polymer composites, which is critical to rationally design interface structures for manipulating the insulation performances.

本文建立了二氧化硅填充硅凝胶中分子结构与离子导电性之间的耦合关系。根据宽带介电频谱,计算了离子电荷浓度和离子扩散系数这两个对离子导电性起关键作用的参数。加入二氧化硅后,离子电荷浓度增加了约四个数量级。由于界面上有更多的短链构象和更多的无定形区域,界面上的链更容易以更高的弛豫频率重新排列,从而增强了离子的扩散过程,并导致硅凝胶复合材料中界面分子弛豫与离子扩散系数之间的负解耦指数。随着气相二氧化硅负载量的增加,离子电导率先增加后降低,这是由于二氧化硅分散的渗流现象造成的。我们的发现加深了人们对绝缘聚合物复合材料中界面结构如何影响离子导电性的理解,这对于合理设计界面结构以控制绝缘性能至关重要。


High-performance shape memory epoxy resin with high strength and toughness: Prepared by introducing hydrogen bonds through polycaprolactone and low melting point alloy

Zhiwei Tuo, Kunzhi Chen, Qiang Zhou, Yubo Wang, Qiushi Wang, Yuyu Zhang, Zhaohua Lin, Yunhong Liang

doi:10.1016/j.compscitech.2024.110510

 

具有高强度和韧性的高性能形状记忆环氧树脂:通过聚己内酯和低熔点合金引入氢键制备而成

Epoxy resin (EP) as common polymers have attracted much attention in the field of shape memory materials due to their excellent properties. However, epoxy-based shape memory polymers suffer from a trade-off between strength, toughness, variable stiffness capability and shape memory properties, and thus are subject to significant limitations in their applications. In this paper, we propose a method to prepare epoxy composites with high strength and toughness and high shape memory properties by introducing a lot of hydrogen bonds. Hydrogen bonding is generated through polycaprolactone (PCL) induced EP phase separation. A low melting point alloy (L) was also added to enhance the shape memory properties of the composites. The synthesis mechanism of EP and the formation mechanism of hydrogen bonding were revealed. The effects of the introduction of hydrogen bonding on the mechanical properties, stiffness and shape memory properties of the composites were investigated. New ideas and design directions are provided for the optimisation of modification of high-performance shape memory epoxy resins.

环氧树脂(EP)作为常见的聚合物,因其优异的性能在形状记忆材料领域备受关注。然而,环氧基形状记忆聚合物在强度、韧性、可变刚度能力和形状记忆性能之间存在权衡问题,因此在应用中受到很大限制。本文提出了一种通过引入大量氢键来制备具有高强度、高韧性和高形状记忆性能的环氧树脂复合材料的方法。氢键是通过聚己内酯(PCL)诱导 EP 相分离产生的。此外,还添加了低熔点合金(L),以增强复合材料的形状记忆性能。研究揭示了 EP 的合成机理和氢键的形成机理。研究了氢键的引入对复合材料机械性能、刚度和形状记忆性能的影响。为优化高性能形状记忆环氧树脂的改性提供了新的思路和设计方向。




来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemInspireDeform断裂复合材料化学电路汽车电子声学裂纹电场理论材料储能气象纺织螺栓
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【新文速递】2024年2月9日复合材料SCI期刊最新文章

今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 5 篇Composite StructuresStructural design and experimental study of CFRP bamboo rat tooth bionic drill bitFei Su, Ke Chen, Xing Liu, Ke Zhang, Xun Dingdoi:10.1016/j.compstruct.2024.117950CFRP 竹鼠齿仿生钻头的结构设计与实验研究The holes are very easy to appear delamination and burr during CFRP drilling. The tool geometry has a great impact on the hole making. In this paper, according to the principle of bionics and structural features, a novel bionic drill bit was designed. The mathematical model of the lower incisor teeth occlusal movement was established. The cutting mechanism of the bamboo rat lower incisor on PW-CFRP material was studied. It was found that the curvature of the contour curves of the front cutter faces were constantly changing, which was conducive to the removal of chips. The curvature change of the contour curve of the rear cutter surface is small and the curve is relatively smooth, which is conducive to reducing friction. The mathematical modeling analysis was carried out on the feeding process of bamboo rats, and the mathematical relationship between the bite radius R and the cutting angle θ was obtained. The optimal cutting angle θ=10° and the corresponding biting radius R=40mm were obtained by finite element simulation. The surface cutting quality of bamboo rat&#39;s lower incisors is better than that of ordinary cutting tools. The novel bionic tool can effectively reduce the burr and delamination of the exit layer.在 CFRP 钻孔过程中,孔很容易出现分层和毛刺。刀具的几何形状对钻孔有很大影响。本文根据仿生学原理和结构特点,设计了一种新型仿生钻头。建立了下门牙咬合运动的数学模型。研究了竹鼠下门齿在 PW-CFRP 材料上的切割机理。研究发现,前刀面轮廓曲线的曲率不断变化,有利于切屑的清除。后刀面轮廓曲线的曲率变化较小,曲线相对平滑,有利于减少摩擦。对竹鼠的进料过程进行了数学建模分析,得到了咬合半径 R 与切削角 θ 之间的数学关系。通过有限元模拟得到了最佳切削角θ=10°和相应的咬合半径R=40mm。竹鼠下门齿的表面切削质量优于普通刀具。新型仿生刀具能有效减少毛刺和出口层的分层。A theoretical study on the temperature-dependent yield strength of in-situ particle and whisker hybrid-reinforced metal matrix compositesRuozhen Zhang, Pan Dong, Xuyao Zhang, Ziyuan Zhao, Weiguo Li, Tianbao Cheng, Xianhe Zhangdoi:10.1016/j.compstruct.2024.117962原位颗粒和晶须混合增强金属基复合材料屈服强度随温度变化的理论研究The hybrid effect observed in hybrid-reinforced composites presents a promising opportunity to further enhance the mechanical properties of composites. In this study, a theoretical model is established to determine the yield strength of in-situ particle and whisker hybrid-reinforced metal matrix composites by considering the mechanisms of stress transfer strengthening and grain boundary strengthening. And the hybrid effect is well characterized. The model is then extended to incorporate temperature dependence, considering changes in key parameters as temperature varies. With only one readily available experimental reference point, yield strength at different temperatures can be conveniently predicted. Satisfactory agreements are achieved between model predictions and experimental data. Moreover, quantitative analyses are performed to examine the hybrid effect at various temperatures and reinforcement volume fractions. The results show that the hybrid effect increases significantly with the increasing reinforcement volume fraction, but as the temperature increases, the hybrid effect decreases in proportion to the matrix yield strength.在混合增强复合材料中观察到的混合效应为进一步提高复合材料的机械性能提供了一个大有可为的机会。本研究建立了一个理论模型,通过考虑应力传递强化和晶界强化机制来确定原位颗粒和晶须混合强化金属基复合材料的屈服强度。并很好地描述了混合效应。然后对模型进行了扩展,纳入了温度依赖性,考虑了温度变化时关键参数的变化。只需一个现成的实验参考点,就能方便地预测不同温度下的屈服强度。模型预测与实验数据之间达到了令人满意的一致。此外,还进行了定量分析,以研究不同温度和钢筋体积分数下的混合效应。结果表明,混合效应随着钢筋体积分数的增加而显著增加,但随着温度的升高,混合效应与基体屈服强度成比例地减小。Fatigue crack growth characterization of composite-to-steel bonded interface using ENF and 4ENF testsWeikang Feng, Marcio Moreira Arouche, Marko Pavlovicdoi:10.1016/j.compstruct.2024.117963利用 ENF 和 4ENF 试验鉴定复合材料与钢粘接界面的疲劳裂纹生长特征In this paper, mode II fatigue crack growth properties of the composite-to-steel interface are characterised through different test configurations, namely ENF and 4ENF tests. Different loading types including force control and displacement control methods are compared. An innovative shear strain based method is proposed for monitoring the mode II crack growth at the bi-material interface through Digital Image Correlation (DIC). A 3D finite element model with Virtual Crack Closure Technique (VCCT) is built and used for obtaining the strain energy release rate (SERR) to investigate the effect of geometrical nonlinearity, friction at the interface and steel yielding, as well as to verify the mode mixity. The results show that the standard 3-point bending ENF specimen can be unstable under force control and sweeps narrow SERR range by a single test under displacement control. The 4-point bending 4ENF test shows stable crack propagation and clear SERR developing trend. More pronounced geometrical nonlinearity and friction effect exist for 4ENF test which can be considered in interpreting the Paris curves by a nonlinear finite element model.本文通过不同的试验配置,即 ENF 和 4ENF 试验,对复合材料与钢材界面的模式 II 疲劳裂纹生长特性进行了表征。比较了不同的加载类型,包括力控制和位移控制方法。提出了一种基于剪切应变的创新方法,通过数字图像相关性(DIC)监测双材料界面的模式 II 裂纹生长。利用虚拟裂缝闭合技术(VCCT)建立了三维有限元模型,并利用该模型获得应变能释放率(SERR),以研究几何非线性、界面摩擦和钢屈服的影响,并验证模式混合性。结果表明,标准的三点弯曲 ENF 试样在力控制下可能不稳定,在位移控制下通过一次试验就能扫过较窄的 SERR 范围。4 点弯曲 4ENF 试验显示出稳定的裂纹扩展和明显的 SERR 发展趋势。4ENF 试验存在更明显的几何非线性和摩擦效应,可通过非线性有限元模型解释巴黎曲线。Vibration suppression of a meta-structure with hybridization of Kresling origami and waterbomb-based origamiHaizhou Shi, Kai Zhang, Xiangbing Liu, Hong Liu, Haijun Peng, Zichen Dengdoi:10.1016/j.compstruct.2024.117964克瑞斯林折纸与水弹折纸杂交的元结构振动抑制技术In recent years, the unfolding capability and vibration-isolation properties of spacecraft have received increasing attention. Several studies have achieved deployability through origami structures and low-frequency broadband vibration isolation using origami-inspired meta-structures(OIMs). However, traditional origami prototypes do not fully satisfy aerospace engineering requirements. In this study, a new origami-inspired meta-structure with low-frequency broadband vibration-isolation performance was proposed by combining the geometric characteristics of Kresling origami and waterbomb-based origami. The bandgap distribution and transmission rate of the OIMs were investigated through numerical simulations and a transient displacement study to evaluate the vibration-isolation performance of the OIMs. Modulation of the band structures by changing the geometric parameters was also examined. Experimental tests were conducted to demonstrate and validate the vibration-isolation properties of the proposed meta-structure. The transmission rate and bandgap results were in good agreement. Wider bandgaps are achieved through the gradient design, and the truss design makes OIMs more suitable for engineering applications. This study presents a new origami-inspired meta-structure that provides a strategy for application of origami in aerospace engineering.近年来,航天器的展开能力和隔振特性日益受到关注。一些研究通过折纸结构实现了可展开性,并利用折纸启发元结构(OIM)实现了低频宽带隔振。然而,传统的折纸原型并不能完全满足航空航天工程的要求。本研究结合克瑞斯林折纸和水弹折纸的几何特性,提出了一种具有低频宽带隔振性能的新型折纸启发元结构。通过数值模拟和瞬态位移研究,研究了 OIM 的带隙分布和传输速率,从而评估了 OIM 的隔振性能。此外,还研究了通过改变几何参数对带状结构进行调制的问题。为证明和验证拟议元结构的隔振性能,还进行了实验测试。传输率和带隙结果非常吻合。通过梯度设计实现了更宽的带隙,而桁架设计则使 OIM 更适合工程应用。本研究提出了一种新的受折纸启发的元结构,为折纸在航空航天工程中的应用提供了一种策略。Composites Part A: Applied Science and ManufacturingEnhancing Oxidation Resistance of Carbon Fibre Reinforced Phenolic Composites by ZrO2 Nanoparticles through Out-of-autoclave Vacuum InfusionZhao Sha, Wenmu Yang, Cheng Wang, Mohammad S. Islam, Guan Heng Yeoh, David L. Officer, Warren Canning, Jin Zhang, Chun H. Wangdoi:10.1016/j.compositesa.2024.108071通过釜外真空灌注 ZrO2 纳米粒子增强碳纤维增强酚醛复合材料的抗氧化性This study reports a vacuum-assisted resin infusion method for achieving low-porosity carbon fibre/phenolic resin composites utilizing a low-viscosity (∼281 cp) phenolic resin enhanced by ZrO2 nanoparticles. The experimental results reveal that this method can yield composites with a low porosity of 8.6±2.5 % and average pore size of 3.8±1.73 μm, while demonstrating mechanical properties that fulfill the requirements for high-temperature structural applications, such as the nozzle of rocket motor. Moreover, the resultant composites exhibit distinct advantages over composites produced using other out-of-autoclave and autoclave methods investigated in this study in terms of flexural strength and modulus after oxidation treatment. The vacuum infusion approach retains higher resin content in composites than the autoclave method, leading to increased residual modulus post-oxidation. Furthermore, incorporating ZrO2 nanoparticles in the phenolic matrix has shown a significant potential in achieving increased residual mass, flexural strength, and flexural modulus of composites, notably after exposure to short-duration oxidation.本研究报告了一种真空辅助树脂灌注方法,该方法利用纳米 ZrO2 增强的低粘度(∼281 cp)酚醛树脂实现低孔隙率碳纤维/酚醛树脂复合材料。实验结果表明,该方法可获得孔隙率为 8.6±2.5 %、平均孔径为 3.8±1.73 μm 的低孔隙率复合材料,同时其力学性能也能满足火箭发动机喷嘴等高温结构应用的要求。此外,就氧化处理后的弯曲强度和模量而言,与本研究中采用其他釜外法和釜内法生产的复合材料相比,所生产的复合材料具有明显优势。与高压釜法相比,真空灌注法在复合材料中保留了更高的树脂含量,从而提高了氧化后的残余模量。此外,在酚醛基质中加入 ZrO2 纳米粒子在增加复合材料的残余质量、抗弯强度和抗弯模量方面具有显著的潜力,尤其是在暴露于短时间氧化后。Bending behaviors and toughening mechanism of carbon fiber-aluminum honeycomb sandwich structures with stitched fiber beltsHaipeng Yu, Hongjie Chen, Bingyi Liang, Zhi Sun, Xu Guodoi:10.1016/j.compositesa.2024.108072带缝合纤维带的碳纤维-铝蜂窝夹层结构的弯曲行为和增韧机理Bending behaviors of carbon fiber-aluminum honeycomb sandwich structures, that are toughened by stitched fiber belts, are experimentally and numerically studied. It is found that the stitched fiber belts show potential to enhance the peak load of sandwich specimens by up to 44.3%, and to arrest interfacial crack growth. Firstly, FE models are proposed for the sandwich structures with stitched carbon fiber belts, and the FE models are verified by three-point bending tests. Secondly, the effects of stitched carbon fiber belts on bending behaviors of sandwich beam are studied. Combining the experimental and numerical results, the main toughening mechanism of stitched fiber belts is observed. The stitched fiber belts increase bonding area between face-sheets and honeycomb core, on one hand, and therefore enhance the interfacial strength. On the other hand, the angled fiber belts inside the core are found to enhance load bearing capacity and transverse shear stiffness.实验和数值研究了通过缝合纤维带增韧的碳纤维-铝蜂窝夹层结构的弯曲行为。研究发现,缝合纤维带有可能将夹层试样的峰值载荷提高 44.3%,并阻止界面裂纹生长。首先,针对带有缝合碳纤维带的夹层结构提出了有限元模型,并通过三点弯曲试验验证了有限元模型。其次,研究了缝合碳纤维带对夹层梁弯曲行为的影响。结合实验和数值结果,观察了缝合纤维带的主要增韧机理。一方面,缝合纤维带增加了面层与蜂窝芯之间的粘合面积,从而提高了界面强度。另一方面,芯材内部的斜纤维带可提高承载能力和横向剪切刚度。Composites Part B: EngineeringReformable and sustainable thermosetting carbon fiber composites from epoxy vitrimerPhilip R. Barnett, Justin A. Brackenridge, Abigail A. Advincula, Laine A. Taussig, Dhriti Nepaldoi:10.1016/j.compositesb.2024.111270环氧玻璃聚合物的可改造和可持续热固性碳纤维复合材料Vitrimers are an emerging class of thermosetting materials that undergo reversible dynamic covalent bonding to enable thermoplastic-like repair, joining, and recycling that is currently inaccessible to traditional thermosets. This work demonstrates the production of sustainable recycled carbon fiber/epoxy based vitrimer composites. A method of preparing B-staged vitrimer films enabled infusion of the vitrimer into a fibrous preform using scalable compression molding techniques to form fully cured, room temperature stored organosheets that were then consolidated into laminates. The influence of consolidation time on the thermo-mechanical properties of the resulting composites was evaluated using several techniques. Short beam strength testing was used to evaluate the interlaminar properties of the composites and assess the repairability of tested specimens. Additional processing time was shown to stiffen the materials at room temperature, due to thermo-oxidative crosslinking as opposed to further thermal cure. This led to an initial improvement in the short beam strength, but a reduction in energy absorption and ductility. The results of this work show that vitrimer composites may be effective in extending the life of in-service composite structures by mitigating or repairing damage.玻璃聚合物是一类新兴的热固性材料,可进行可逆的动态共价键合,从而实现类似热塑性塑料的修复、连接和回收,这是传统热固性材料目前无法实现的。这项研究展示了可持续再生碳纤维/环氧树脂基玻璃纤维复合材料的生产过程。采用一种制备 B 级玻璃聚合物薄膜的方法,利用可扩展的压缩成型技术将玻璃聚合物注入纤维预型件中,形成完全固化、室温储存的有机片材,然后将其加固成层压板。我们使用多种技术评估了固化时间对所得复合材料热机械性能的影响。短梁强度测试用于评估复合材料的层间性能,并评估测试试样的可修复性。结果表明,由于热氧化交联而非进一步的热固化,额外的加工时间可使材料在室温下更加坚硬。这使得短梁强度得到初步改善,但能量吸收和延展性有所降低。这项工作的结果表明,通过减轻或修复损坏,玻璃纤维复合材料可以有效延长在用复合材料结构的寿命。Metal-electronegativity-induced sulfur-vacancies and heterostructures of MnS1-x/ZnS-NC@C with dual-carbon decoration for high-performance sodium-ion storageHongyu Zhang, Zhenjiang Lu, Baolin Liu, Chun Yuan, Yali Caodoi:10.1016/j.compositesb.2024.111267 金属负电荷诱导的硫空位和具有双碳装饰的 MnS1-x/ZnS-NC@C 异质结构用于高性能钠离子存储Engineering unique architectural anode electrode materials with high storage capacity and stable structures to balance kinetics and capacity between anode and cathode possesses a huge challenge for sodium-ion hybrid capacitors (SIHCs). Herein, beginning with well-organized MnS nanoparticles, an elaborate design of introducing metal-organic frameworks and decorating with dual-carbon is presented to fabricate a desirable composite of bimetallic sulfide and carbon with carbon matrix/coating layers via electronegativity induction. The simultaneously formed rich sulfur-vacancies and heterostructures can significantly boost fast electron/ion diffusion kinetics and induce high reversible sodium-ion storage capacities. Moreover, dual-carbon decoration tactics allow the electrodes for superior electronic conductivity, guarantee a splendid structural stability and offer an avenue for electron transport, which enable MnS1-x/ZnS-NC@C (MSZNC) composites a steady capacity of 354 mAh g−1 for 1600 cycles at a high rate of 10 A g−1 in sodium-ion batteries (SIBs). Integrated with theoretical calculations, the systemic electrochemical kinetic analytical results reveal that the synergistic effect of heterostructures and sulfur-vacancies can furnish more reversible active sites and boost charge transfer, thereby accelerating reaction kinetics for an enhanced sodium-ion storage capability. As expected, the assembled SIHCs full cell based on MSZNC anode and AC cathode exhibits a high energy density of 116 W h kg−1 and a high power output of 95 W kg−1, a capacity retention of 87% at 2 A g−1 for 2000 cycles, certifying its practical applications potential on a wide scale for sodium-based energy storage devices.对于钠离子混合电容器(SIHC)来说,如何设计具有高存储容量和稳定结构的独特建筑阳极电极材料,以平衡阳极和阴极之间的动力学和容量,是一个巨大的挑战。本文从组织良好的 MnS 纳米颗粒入手,精心设计了引入金属有机框架和双碳装饰的方法,通过电负性诱导制造出理想的双金属硫化物和碳复合材料,并带有碳基质/涂层层。同时形成的丰富硫空位和异质结构可显著提高电子/离子的快速扩散动力学,并诱导出较高的可逆钠离子存储容量。此外,双碳装饰策略使电极具有卓越的电子传导性,保证了出色的结构稳定性,并为电子传输提供了途径,从而使 MnS1-x/ZnS-NC@C (MSZNC) 复合材料在钠离子电池(SIB)中以 10 A g-1 的高倍率循环 1600 次后,仍能保持 354 mAh g-1 的稳定容量。结合理论计算,系统电化学动力学分析结果表明,异质结构和硫空位的协同效应可以提供更多可逆活性位点并促进电荷转移,从而加速反应动力学以增强钠离子存储能力。正如预期的那样,基于 MSZNC 阳极和交流阴极组装的 SIHCs 全电池表现出 116 W h kg-1 的高能量密度和 95 W kg-1 的高功率输出,在 2 A g-1 循环 2000 次的情况下容量保持率为 87%,这证明了其在钠基储能设备方面的广泛实际应用潜力。Composites Science and TechnologyFabrication of knitted Polyethylene/SiO2 composite membrane modules for one-step microfiltration and particle removal in wastewater treatmentDan Guo, Jianguo Xu, Xiaodong Zhang, Ngie Hing Wong, Jaka Sunarso, Shaomin Liu, Nana Lidoi:10.1016/j.compscitech.2024.110479 编织聚乙烯/二氧化硅复合膜组件,用于废水处理中的一步式微滤和颗粒去除Sewage treatment efficiency is affected by the membrane module design. In this study, SiO2 was employed as additives in the formation of polyethylene/SiO2 hollow fibre composite membranes using the thermally induced phase separation (TIPS) method. This approach effectively addressed the limitations of pure polyethylene hollow fibres, such as poor network pore structure and low flux. The investigation revealed that the addition of SiO2 enhanced gas flux by 30%, increased porosity by 20%, and provided a commendable tensile strength of 2.1 MPa, suitable for weaving knitted composite membrane module. The voids of the membrane module facilitated particle filtration and microfiltration through micropores of the composite membrane, successfully integrated into a one-step wastewater treatment process. The knitted composite membrane module&#39;s particle filtration process effectively intercepted all particles A (30 μm), and the microfiltration process rejected particles B (1.3 &lt; size &lt;15 μm). During these processes, the rejection rate of talc powder in the membrane module was as high as 90%, and the gas flux was remained at 1200 L m−2∙min−1. The strategy of knitted composite membrane modules demonstrates versatility in applications and has the potential for expanding the design to various microporous hollow fibre materials for diverse separation purposes.污水处理效率受膜组件设计的影响。本研究采用热诱导相分离(TIPS)法,将二氧化硅作为添加剂用于聚乙烯/二氧化硅中空纤维复合膜的形成。这种方法有效地解决了纯聚乙烯中空纤维的局限性,如网络孔隙结构差和通量低。研究表明,加入二氧化硅后,气体通量提高了 30%,孔隙率增加了 20%,抗拉强度达到 2.1 兆帕,适合编织针织复合膜组件。膜组件的空隙有利于通过复合膜的微孔进行颗粒过滤和微过滤,成功地集成到一步式污水处理工艺中。针织复合膜组件的颗粒过滤过程有效地拦截了所有颗粒 A(30 μm),而微滤过程则剔除了颗粒 B(1.3 &lt; 粒径 &lt;15 μm)。在这些过程中,膜组件对滑石粉的截留率高达 90%,气体通量保持在 1200 L m-2∙min-1。编织复合膜组件的策略展示了应用的多样性,并有可能将设计扩展到各种微孔中空纤维材料,以实现不同的分离目的。Flexible phase change composites with multiple colors and reversible thermochromic for temperature indication and battery thermal managementYujiao Li, Zhuoni Jiang, Yongsheng Li, Fangfang He, Zhengguo Chen, Xiaoan Li, Peng Wang, Guansong He, Wenbin Yangdoi:10.1016/j.compscitech.2024.110481 具有多种颜色和可逆热致变色功能的柔性相变复合材料,用于温度指示和电池热管理In this paper, a series of silicone rubber (SR)/thermochromic microcapsules (TC@MF)/cuprous oxide (Cu2O) flexible phase change composites (STC) with multi-colors and reversible thermochromic were prepared. In this composite, SR was used as polymer matrix and TC@MF with phase change enthalpy of 193 J/g was used as functional filler. Moreover, different contents of Cu2O were introduced to change color of composites and improve thermal conductivity and photothermal conversion. The STC composites could undergo reversible color changes from blue-violet to red with a color change temperature of approximately 52 °C. And it exhibited excellent leakage resistance with the leakage rate of STC-2 as low as 0.41%. The thermal conductivity of the STC-3 composite reached 0.33 W m−1 K−1 at Cu2O content of 9 phr. The STC composites were applied to dissipate heat from the battery and the maximum surface temperature was only 49.0 °C at 9.8 A discharge rate which represented 24.03 % reduction in surface temperature compared to the bare battery. This work offers an effective route for preparation of battery thermal regulation materials based on thermochromic microcapsules, which has significant potential for application in the field of battery thermal management.本文制备了一系列具有多色和可逆热致变色功能的硅橡胶(SR)/热致变色微胶囊(TC@MF)/氧化亚铜(Cu2O)柔性相变复合材料(STC)。在该复合材料中,SR 用作聚合物基体,相变焓为 193 J/g 的 TC@MF 用作功能填料。此外,还引入了不同含量的 Cu2O,以改变复合材料的颜色,并提高热导率和光热转换率。STC 复合材料可以实现从蓝紫色到红色的可逆变色,变色温度约为 52 ℃。此外,STC-2 还具有出色的抗泄漏性能,泄漏率低至 0.41%。当 Cu2O 含量为 9 phr 时,STC-3 复合材料的热导率达到 0.33 W m-1 K-1。STC 复合材料用于电池散热,在放电率为 9.8 A 时,最大表面温度仅为 49.0 °C,与裸电池相比,表面温度降低了 24.03%。这项工作为制备基于热致变色微胶囊的电池热调节材料提供了一条有效途径,在电池热管理领域具有巨大的应用潜力。Advanced composite armor protection systems for military vehicles: Design methodology, ballistic testing, and comparisonEvangelos Tsirogiannis, Evangelos Daskalakis, Christos Vogiatzis, Foivos Psarommatis, Paulo Bartolodoi:10.1016/j.compscitech.2024.110486 军用车辆的先进复合装甲防护系统:设计方法、弹道测试和比较This study presents a new methodology for designing, manufacturing, and testing advanced armor protection systems and applied to the development of three different protection solutions suitable for real armored vehicles. The backplate laminates of the presented composite armor protection solutions were composed of three different materials: steel, aluminum AA6082, and aluminum alloy AA2024 reinforced by multi-walled carbon nanotubes (MWCNTs). The frontal laminates remained the same for the three cases. Keeping almost the same mass while changing the material of each backplate and adapting the thickness, the three different protection systems were ballistically tested and compared according to Level 4 (Level IV) of the standard AEP-STANAG 4569 (projectile 14.5 mm × 114 mm API B32) with real military tests. Furthermore, the performance of the total laminated structure and the performance of each backplate in the total laminated structure were compared in terms of deformation and ballistic fractures. High-quality images acquired by the high-speed camera were helpful in evaluating and comparing the backplates and the entire protection system. The results show that all three protection configurations present high performance mechanical properties and ballistic characteristics compared to commonly used armor systems. Even the under-developed AA2024-CNTs composite is a promising near-term backplate solution.本研究介绍了一种设计、制造和测试先进装甲防护系统的新方法,并将其应用于开发适合真实装甲车辆的三种不同防护解决方案。所介绍的复合装甲防护解决方案的背板层压板由三种不同的材料组成:钢、铝 AA6082 和由多壁碳纳米管(MWCNTs)增强的铝合金 AA2024。三种方案的正面层压板保持不变。在改变背板材料和厚度的同时,保持几乎相同的质量,对三种不同的防护系统进行了弹道测试,并根据 AEP-STANAG 4569 标准第 4 级(第 IV 级)(射弹 14.5 毫米 × 114 毫米 API B32)与实际军事测试进行了比较。此外,还从变形和弹道断裂的角度对整体层压结构的性能和整体层压结构中每块背板的性能进行了比较。高速摄像机获得的高质量图像有助于评估和比较背板和整个保护系统。结果表明,与常用的装甲系统相比,所有三种防护配置都具有高性能的机械性能和弹道特性。即使是尚未充分开发的 AA2024-CNTs 复合材料也是一种很有前景的近期背板解决方案。Experimental method for in-situ real-time measurement of mixed mode fibre/matrix interface debonding and comparison of fibre sizings in single short fibre compositesMehdi Nikforooz, Olivier Verschatse, Lode Daelemans, Karen De Clerck, Wim Van Paepegemdoi:10.1016/j.compscitech.2024.110488 原位实时测量混合模式纤维/基体界面脱胶的实验方法以及单根短纤维复合材料中纤维尺寸的比较In short fibre composites, off-axis fibres are potentially subject to mixed-mode loading, which results in interactive debonding growth in opening and sliding modes. This synergy might differ for strong and weak fibre/matrix bondings inducing discrete debonding patterns. This study employed an optical visualization technique to investigate, for the first time, the mixed-mode debonding growth for short fibres with different sizings and off-axis angles, through in-situ real-time measurements. For this purpose, embedded single short-fibre specimens were fabricated using E-glass fibres and an epoxy matrix, with a novel and more efficient manufacturing method than done so far in literature. E-glass fibres with two different sizings were utilized, including a polypropylene-compatible (weak) sizing and an epoxy-compatible (strong) sizing. While there was a relatively rapid debonding growth for the transverse fibres with the weak sizing, the strong sizing experienced a gradual debonding growth independent of the fibre angle. For the weak sizing, partial debonding cracks were initiated at different locations along the length of the fibres, where they coalesced into dominant debonding cracks. For the strong sizing, debonding was always initiated and localized at the fibre tip, and there was a clear synchronous propagation of debonding in the arc and length of the fibre.在短纤维复合材料中,偏离轴线的纤维可能会受到混合模式加载的影响,从而导致开放模式和滑动模式下的交互脱粘增长。这种协同作用可能会因纤维/基体粘合力的强弱而不同,从而诱发离散的脱粘模式。本研究采用光学可视化技术,通过原位实时测量,首次研究了不同尺寸和离轴角的短纤维的混合模式脱胶增长。为此,我们使用 E 玻璃纤维和环氧树脂基体制作了嵌入式单根短纤维试样,与迄今为止的文献相比,这种制作方法更新颖、更高效。使用了两种不同规格的 E 玻璃纤维,包括聚丙烯相容(弱)规格和环氧树脂相容(强)规格。采用弱施胶的横向纤维脱胶相对较快,而采用强施胶的横向纤维则逐渐脱胶,与纤维角度无关。对于弱施胶,部分脱胶裂纹开始出现在纤维长度的不同位置,并在这些位置凝聚成主要的脱胶裂纹。对于强施胶,脱胶总是在纤维顶端开始并局部出现,脱胶在纤维的弧度和长度上明显同步扩展。Honeycomb-like Polyimide/Fe3O4@PPy foam for electromagnetic wave shielding with excellent absorption characteristicsWei Chu, Jianwei Li, Jun Lin, Wen Li, Jiazhi Xin, Fei Liu, Xinhai He, Zhonglei Ma, Qiangli Zhaodoi:10.1016/j.compscitech.2024.110489 用于电磁波屏蔽的蜂窝状聚酰亚胺/Fe3O4@PPy 泡沫,具有优异的吸收特性Electromagnetic interference (EMI) shielding materials with low reflection and excellent microwave absorption characteristics are highly desirable for high-speed electronics devices to attenuate radiated emissions. Herein, we developed a highly absorption dominated composite EMI shielding foams with “honeycomb” structure through chemical foaming and subsequent in situ vapor deposition of polypyrrole (PPy) within polyimide (PI) foams. After the deposition of PPy, the obtained porous PI foams exhibit electrical conductivity of 2.7 × 103 S/m. In addition, the composite foams demonstrate the highest absorption coefficient of 0.8 and EMI shielding efficiency of 41.1 dB with a thickness of 8 mm. Moreover, the optimal reflection loss (RL) of the composite PI/Fe3O4-20@PPy foam (PF/Fe3O4-20@PPy) reach up to −31 dB at 6.0 mm and ≤ −10 dB in the whole X band with a thickness of ≥4 mm. Moreover, the 3D porous structure of PI foam and favorable electrical conductivity of in-situ formed PPy film can contribute to the high sensing performance of PI@PPy foam (PF@PPy). This study provides a novel strategy for the development of lightweight, EMI shielding and microwave absorption materials for advanced applications in flexible anti-radiation and stealth devices.具有低反射和优异微波吸收特性的电磁干扰(EMI)屏蔽材料是高速电子设备衰减辐射发射的理想材料。在此,我们通过化学发泡,并随后在聚酰亚胺(PI)泡沫中原位气相沉积聚吡咯(PPy),开发出一种具有 &quot;蜂窝 &quot;结构的高吸收主导型复合 EMI 屏蔽泡沫。沉积 PPy 后,得到的多孔 PI 泡沫的导电率达到 2.7 × 103 S/m。此外,复合泡沫的吸收系数最高,为 0.8,EMI 屏蔽效率为 41.1 dB(厚度为 8 毫米)。此外,PI/Fe3O4-20@PPy 复合泡沫(PF/Fe3O4-20@PPy)的最佳反射损耗(RL)在 6.0 mm 时高达 -31 dB,厚度≥4 mm 时整个 X 波段的最佳反射损耗(RL)≤ -10 dB。此外,PI 泡沫的三维多孔结构和原位形成的 PPy 薄膜良好的导电性也有助于 PI@PPy 泡沫(PF@PPy)实现高传感性能。这项研究为开发轻质、电磁干扰屏蔽和微波吸收材料提供了一种新的策略,可用于柔性抗辐射和隐形设备的高级应用。来源:复合材料力学仿真Composites FEM

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