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【新文速递】2024年8月24日复合材料SCI期刊最新文章

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今日更新:Composite Structures 8 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 3 篇

Composite Structures

Analysis of the fracture behavior and mechanism of PIP-C/SiC composites at high temperatures

Kunjie Wang, Chenghai Xu, Bo Gao, Leying Song, Songhe Meng

doi:10.1016/j.compstruct.2024.118491

PIP-C/SiC复合材料高温断裂行为及机理分析

The high-temperature fracture toughness of C/SiC composites is of great significance for the tolerance assessment and safety application of components in service. In this work, combining the high-temperature experimental technique and phase field method, the fracture toughness of PIP-C/SiC composites at 25–1600 ℃ in inert atmosphere was tested, and the microcrack propagation at different temperatures was simulated. The fracture model considers the effects of residual stress, temperature-dependent properties of constituents and interfacial graphitization on the crack propagation process. The results show that the fracture toughness and modes of C/SiC composites have significant temperature dependence and difference in in-plane and out-of-plane orientations. As the increase of temperature, the cracks exhibit three typical modes of deflection, penetration and long-debonding at the fiber–matrix interphase. It is worth noting that C/SiC composites show a unique fracture mode at 1600 ℃ with the work of fracture increasing significantly. Overall, the work provides a guidance for the damage tolerance assessment of C/SiC composites in engineering.

C/SiC复合材料的高温断裂韧性对服役部件的公差评定和安全应用具有重要意义。本文将高温实验技术与相场法相结合,测试了PIP-C/SiC复合材料在25 ~ 1600℃惰性气氛下的断裂韧性,并模拟了不同温度下的微裂纹扩展。该断裂模型考虑了残余应力、组分温度相关特性和界面石墨化对裂纹扩展过程的影响。结果表明:C/SiC复合材料的断裂韧性和断裂模式具有显著的温度依赖性,且面内取向和面外取向存在显著差异;随着温度的升高,裂纹在纤维-基体界面处呈现出挠曲、穿透和长脱粘三种典型模式。值得注意的是,C/SiC复合材料在1600℃时呈现出独特的断裂模式,断裂功显著增加。研究结果对工程中C/SiC复合材料的损伤容限评价具有一定的指导意义。


Development of a geometric modeling strategy for the generation of representative unit cells in 2D braids

José Rothkegel, Benjamin Renson, Michaël Bruyneel, Ludovic Noels

doi:10.1016/j.compstruct.2024.118503

二维编织中代表性单元细胞生成的几何建模策略的发展

This article presents, tests and validates a method for generating representative unit cells of braided composites based on a geometrical approach. The method focuses on the geometry of the tows and uses surface minimization to obtain the minimal equivalent area of a central surface that is used for the generation of volumes and orthotropic mechanical properties of the tows. The homogenization of the yarns is solved using analytical equations and the homogenization of the cell is solved using a representative volume element technique. The robustness of the method is evaluated using a benchmark comparison with experimental and numerical results to validate the generated ge.ometry. The method is also tested and shown to be robust in modeling the geometry for several values of geometrical parameters of the tows without user intervention, including for configurations yielding a high cover factor.

本文提出并试验验证了一种基于几何方法的编织复合材料代表性单元胞的生成方法。该方法侧重于拖曳的几何形状,并使用表面最小化来获得中心表面的最小等效面积,该中心表面用于生成拖曳的体积和正交异性力学特性。采用解析方程求解纱线的均匀化问题,采用代表性体积元技术求解单元的均匀化问题。通过与实验和数值结果的对比,验证了该方法的鲁棒性。该方法还经过了测试,结果表明,在没有用户干预的情况下,该方法在对拖曳几何参数的几个值进行几何建模方面具有鲁棒性,包括产生高覆盖系数的配置。


Design optimization of lightweight automotive seatback through additive manufacturing compression overmolding of metal polymer composites

Deepak Kumar Pokkalla, Nikhil Garg, Mithulan Paramanathan, Vipin Kumar, Mitchell L. Rencheck, Peeyush Nandwana, Vlastimil Kunc, Ahmed Arabi Hassen, Seokpum Kim

doi:10.1016/j.compstruct.2024.118504

 

金属聚合物复合材料增材制造压缩复模轻量化汽车座椅靠背设计优化

With the growing demand for enhanced automotive fuel efficiency and environmental sustainability, there is a need for lightweighting automotive components through innovative design and manufacturing processes. This study leverages a combination of numerical iterative design optimization and hybrid additive manufacturing – compression molding (AM-CM) technique for metal polymer composites to lightweight an automotive seatback. The AM-CM process enables robust mechanical interlocking between metals and composites, boasting high stiffness and strength with low overall density. Replacing metallic components with such metal polymer composites allows for comparable mechanical performance while significantly reducing the overall weight. First, the automotive seatback design space is reduced to critical load carrying regions using topology optimization and high stress concentration areas are identified using finite element analysis. Next, a lightweight metal polymer subcomponent is designed for a high stress concentration region. The full seatback frame with spatially heterogenous material-specific design is then iteratively optimized to enable enhanced stiffness with minimal weight. Overall, the automotive seatback frame designed with location-specific metal, polymer, and metal polymer composite materials weighs 20% less than the metal-only design while exhibiting similar stiffness.

随着对提高汽车燃油效率和环境可持续性的需求不断增长,需要通过创新的设计和制造工艺来实现轻量化汽车零部件。本研究利用数值迭代设计优化和混合增材制造-压缩成型(AM-CM)技术相结合的金属聚合物复合材料轻量化汽车座椅靠背。AM-CM工艺能够在金属和复合材料之间实现强大的机械联锁,具有高刚度和强度,整体密度低。用这种金属聚合物复合材料代替金属部件,在显著降低整体重量的同时,具有相当的机械性能。首先,利用拓扑优化将汽车座椅靠背设计空间缩小到临界承载区域,并利用有限元分析确定高应力集中区域。其次,为高应力集中区设计了轻质金属聚合物子部件。然后,采用空间异质材料特定设计的全椅背框架进行迭代优化,以最小的重量增强刚度。总体而言,采用特定位置的金属、聚合物和金属聚合物复合材料设计的汽车座椅靠背框架比纯金属设计轻20%,同时具有相似的刚度。


Characterization and analysis of conduction welded thermoplastic composite joints considering the influence of manufacturing

B.H.A.H. Tijs, A. Turon, C. Bisagni

doi:10.1016/j.compstruct.2024.118505

考虑制造影响的热塑性复合材料传导焊接接头的表征与分析

Thermoplastic composite welding is a key technology that can help to make the aviation industry more sustainable, while at the same time enable high-volume production and cost-efficient manufacturing. In this work, characterization, testing and analysis of thermoplastic composite conduction welded joints is performed while accounting for the influence of the manufacturing process. Test specimens are designed from welds of a half a meter long welding tool that is developed to weld the stiffened structures of the next-generation thermoplastic composite fuselage. In the design, special attention is paid to the weldability of the laminates, while ensuring fracture occurs only at the welded interface. Two specimen configurations are evaluated for the Double Cantilever Beam and End-Notched Flexure characterization tests. Moreover, Single Lap-Shear specimens are tested in tension and in three-point-bending. Finally, the characterized material properties are introduced in finite element analyses to demonstrate that the cohesive zone modeling approach can be used to conservatively predict the strength of these welded joints. New insights are obtained in the relation between the manufacturing process, the quality of the weld and the mechanical properties of the joints, which are significantly different compared to autoclave consolidated composites.

热塑性复合材料焊接是一项关键技术,可以帮助航空业更具可持续性,同时实现大批量生产和成本效益制造。本文对热塑性复合材料导电焊接接头进行了表征、测试和分析,同时考虑了制造工艺的影响。测试样品是由半米长的焊接工具设计的,该焊接工具是为焊接下一代热塑性复合材料机身的强化结构而开发的。在设计中,特别注意层压板的可焊性,同时确保仅在焊接界面处发生断裂。两种试样配置评估双悬臂梁和端缺口弯曲表征试验。此外,还对单弯剪试件进行了拉伸和三点弯曲试验。最后,在有限元分析中引入了表征的材料性能,证明了黏聚区建模方法可以保守地预测这些焊接接头的强度。在制造工艺、焊缝质量和接头力学性能之间的关系方面获得了新的见解,这与热压釜固结复合材料相比有明显的不同。


Development of a numerical and analytical methodology for analyzing hybrid laminates with multi-oriented piezoelectric and structural layers

Janice Longo, Matheus Rodrigues Silva, Humberto Brito-Santana, António J.M. Ferreira, Volnei Tita, Ricardo de Medeiros

doi:10.1016/j.compstruct.2024.118506

发展了一种多取向压电层和结构层混合层板的数值分析方法

Piezoelectric materials can generate an electrical response under mechanical stress, functioning as sensors. Conversely, applying an electrical field to these materials enables precise motion control, making them effective as actuators. This work focuses on evaluating the effective properties of hybrid multi-oriented composite laminates consisting of structural and piezoelectric layers driven by monoclinic constitutive equations. Square unit cell model was used to calculate all coefficients of the material tensor. The finite element (FE) homogenization method and periodic boundary conditions implemented by node-to-node constraint equations are used to study a representative volume element (RVE) modeled as three-layer unit cell in the mesoscale. The pre-processing, FE analysis, and post-processing are conducted in the FE package ABAQUSⓇ through Python scripts. The computational approach yields results that align closely with the analytical effective coefficients derived from the Asymptotic Homogenization Method (AHM), demonstrating the robustness and accuracy of our methodology.

压电材料可以在机械应力下产生电响应,起到传感器的作用。相反,在这些材料上施加电场可以实现精确的运动控制,使它们成为有效的致动器。本文研究了单斜本构方程驱动下由结构层和压电层组成的杂化多取向复合材料层合板的有效性能。采用平方单元胞模型计算材料张量的所有系数。采用有限元均匀化方法和节点对节点约束方程实现的周期边界条件,研究了一种具有代表性的中尺度三层单元格体单元。预处理、有限元分析和后处理在有限元包ABAQUSⓇ中通过Python脚本进行。计算方法产生的结果与从渐近均匀化方法(AHM)导出的解析有效系数密切一致,证明了我们的方法的鲁棒性和准确性。


Identification of mode I fracture toughness in GFRP/Al and GFRP/Cu joints for structural batteries

Maryam Niazi, Federico Danzi, Ricardo Carbas, Pedro P. Camanho

doi:10.1016/j.compstruct.2024.118509

结构电池用GFRP/Al和GFRP/Cu接头的I型断裂韧性鉴定

Fibre metal laminates (FMLs) have been proposed as components of structural batteries, yet their elastic mismatch can lead to interface cracks, compromising structural integrity and both mechanical and electrochemical efficiency. To this end, the bonding between the metal and the composite layer is of utmost importance. In this study, the effect of various metal surface treatments on the mode I interlaminar fracture toughness of two FML configurations suitable for structural batteries—Glass Fibre Reinforced Polymer (GFRP)/aluminum laminate and GFRP/copper laminate—was examined. The surface treatments included sulfo-ferric etching, NaOH/HNO3 etching, and Sol-Gel anodizing for aluminum 2024-T3, as well as FeCl3/HCl/Glycerol treatment and Sol-Gel anodizing for copper alloy. The results were compared with untreated conditions and with the baseline GFRP/GFRP configuration. GFRP/metal coupons were designed to achieve pure mode I interlaminar fracture toughness in double cantilever beam (DCB) tests, and the designs were verified using the Virtual Crack Closure Technique (VCCT). The surface characterization of the metals was performed using contact angle tests to estimate the surface free energy, while Coherence Scanning Interferometry (CSI) was used to measure the surface roughness and topography.

金属纤维层压板(FMLs)已被提出作为结构电池的组件,但其弹性失配会导致界面裂缝,从而影响结构完整性以及机械和电化学效率。为此,金属和复合层之间的结合是至关重要的。在本研究中,研究了不同金属表面处理对两种适用于结构电池的FML结构——玻璃纤维增强聚合物(GFRP)/铝层压板和GFRP/铜层压板的I型层间断裂韧性的影响。铝2024-T3的表面处理包括硫铁蚀刻、NaOH/HNO3蚀刻和溶胶-凝胶阳极氧化,铜合金的表面处理包括FeCl3/HCl/甘油处理和溶胶-凝胶阳极氧化。将结果与未经治疗的情况和基线GFRP/GFRP配置进行比较。在双悬臂梁(DCB)试验中,设计了GFRP/金属板,以实现纯I型层间断裂韧性,并使用虚拟裂纹闭合技术(VCCT)对设计进行了验证。金属的表面表征采用接触角测试来估计表面自由能,而相干扫描干涉测量(CSI)用于测量表面粗糙度和形貌。


A mesoscale mechanical model of needle-punched carbon/carbon composite with beam-brick combined element

Yehan Fan, Chuwei Zhou, Yingxuan Zhang, Zhongxiao Zhang, Xin Li, Xuanze Yan, Wangchao Feng

doi:10.1016/j.compstruct.2024.118510

含梁砖复合单元的针 刺碳/碳复合材料中尺度力学模型

Needle punching carbon/carbon composite (NP C/C) has merits of high specific stiffness and strength and especially of excellent high-temperature strength retention, meanwhile it possesses improved interlaminate strength with relatively low manufacturing cost. But the needle punching technology may damage its in-plane properties for introducing local defeats inevitably. A mechanical prediction of NP C/C reflecting its meso-scale architectural features is desired.In this study, a beam-brick combined finite element (BBE) model was developed for predicting the mechanical behaviors and damage processes of NP C/C. In this model, beam elements represent the fiber directional properties in unidirectional fiber cloth (UDC) ply and short cut fiber felt (SCF) ply, while brick elements simulate properties of other directions in them. The displacement compatibility between beam and brick elements was established via their shape functions. The damage laws were employed in these two elements. The proposed model was used to simulate tensile and compressive experiments of an NP C/C and good agreements with test data were found. This BBE model can characterize the meso-structure and main mechanical behaviors of NP C/C and its meso-structure modeling is simpler and the computation requirement is lower compared with the traditional meso-mechanic models which built all with brick elements.

针冲碳/碳复合材料(NP C/C)具有较高的比刚度和强度,特别是具有优异的高温强度保持性,同时具有较好的层间强度和较低的制造成本。但针冲技术不可避免地会因引入局部缺陷而破坏其面内特性。需要一个反映其中尺度结构特征的NP C/C的力学预测。在本研究中,建立了用于预测NP - C/C的力学行为和损伤过程的梁-砖组合有限元模型。在该模型中,束单元表示单向纤维布(UDC)层和短切纤维毡(SCF)层中纤维的方向特性,砖单元模拟其中其他方向的特性。通过梁与砖的形状函数,建立了梁与砖的位移协调关系。损害法适用于这两个要素。将所提出的模型应用于NP - C/C的拉伸和压缩试验,与试验数据吻合较好。该模型能较好地表征NP - C/C的细观结构和主要力学行为,与传统的全砖细观力学模型相比,其细观结构建模更简单,计算量更低。


Physics-constrained deep learning approach for solving inverse problems in composite laminated plates

Yang Li, Detao Wan, Zhe Wang, Dean Hu

doi:10.1016/j.compstruct.2024.118514

求解复合材料层合板逆问题的物理约束深度学习方法

The applications of physics-informed neural networks (PINNs) in material parameters identification of composite laminates are currently research highlights. We present an efficient physics-constrained deep learning approach based on PINNs for solving material parameters of composite laminates. We explain the details of incorporating first-order shear deformation theory as physical information into designed loss functions. The performance of proposed approach is demonstrated through a numerical example of idealized composite laminated plates under uniform pressure conditions. The computational errors of material parameters are less than 0.1%. Moreover, the applicability of transfer learning (TL) has been illustrated for inversion of material parameters with few datasets. The ambition is to improve the identification efficiency of carbon and glass fiber reinforced plies material parameters across various loading conditions. Intensive studies are conducted to compare convergence time between with and without TL through a numerical example under thermal-force coupling conditions. The comparison shows PINNs with TL obtain average error of 0.144% and 0.077% in carbon and glass fiber reinforced plies, which is better than without TL of 0.472% and 0.284%, respectively. The proposed work emphasizes the effective application of PINNs-based approach that combines first-order deformation and data-driven solution features for inverse solving material parameters of composite laminates.

物理信息神经网络(pinn)在复合材料层合板材料参数识别中的应用是目前研究的热点。我们提出了一种有效的基于pinn的物理约束深度学习方法来求解复合材料层合板的材料参数。我们解释了将一阶剪切变形理论作为物理信息纳入设计损失函数的细节。通过均匀压力条件下理想复合材料层合板的数值算例验证了该方法的性能。材料参数的计算误差小于0.1%。此外,迁移学习(TL)在少量数据集的材料参数反演中的适用性也得到了证明。目标是提高碳和玻璃纤维增强层材料参数在不同载荷条件下的识别效率。通过一个热力耦合条件下的数值算例,对有TL和无TL的收敛时间进行了深入研究。对比结果表明,在碳纤维和玻璃纤维增强层中,加TL的pinn平均误差为0.144%和0.077%,优于不加TL的0.472%和0.284%。本文强调了基于pons的方法的有效应用,该方法结合了一阶变形和数据驱动的解特征来反求解复合材料层合板的材料参数。


Composites Part A: Applied Science and Manufacturing

Dependence of the mechanical properties of nylon-carbon fiber composite on the FDM printing parameters

A. Gómez-Ortega, S. Piedra, G.C. Mondragón-Rodríguez, N. Camacho

doi:10.1016/j.compositesa.2024.108419

 

尼龙-碳纤维复合材料力学性能对FDM打印参数的影响

Nylon-based polymer reinforced with short carbon fibers (PA-CFs), fabricated using the Fused Deposition Modeling (FDM) 3D printing process, has been proposed for various applications. However, the mechanical performance of these materials as a function of printing parameters, including wall thickness at infill contents < 100 %, has yet to be reported in the literature. This paper focuses on the effects of infill percentage, nozzle temperature, and wall thickness on the porosity content, microstructure, and mechanical properties of PA-CF specimens. Employing a Taguchi (L9 − 3^3) design of experiments, tensile and flexural testing were conducted to assess their mechanical response. The printing temperature induces microstructural changes, promoting interlayer debonding due to voids and pores at wall- and skin-core interfaces. Wall thickness significantly impacts tensile strength and can be maintained between 0.8 and 1.35 mm for maximum flexural strength, while maximal tensile strength can only be achieved with a wall thickness between 1.15 and 1.5 mm.

采用熔融沉积建模(FDM) 3D打印工艺制备的尼龙基短碳纤维增强聚合物(PA-CFs)已被提出用于各种应用。然而,这些材料的力学性能作为打印参数的函数,包括填充物含量 < 100 %时的壁厚,尚未在文献中报道。本文主要研究了填充率、喷嘴温度和壁厚对PA-CF试样孔隙率、微观结构和力学性能的影响。采用田口(L9−3^3)实验设计,进行拉伸和弯曲测试以评估其力学响应。打印温度引起微观结构的变化,促进了由于壁和皮核界面上的空隙和孔隙而产生的层间脱粘。壁厚对抗拉强度影响显著,最大抗弯强度可保持在0.8 ~ 1.35 mm之间,而最大抗拉强度只能在1.15 ~ 1.5 mm之间实现。


Characterization of thermomechanical properties and damage mechanisms using acoustic emission of Lygeum spartum PLA 3D-printed biocomposite with fused deposition modelling

Khalil Benabderazag, Zouheyr Belouadah, Moussa Guebailia, Lotfi Toubal

doi:10.1016/j.compositesa.2024.108426

利用声发射表征Lygeum spartum PLA 3d打印生物复合材料的热力学性能和损伤机制与熔融沉积建模

This study examines the morphological, physicochemical, mechanical, and thermal properties of 3D-printed biocomposite fabricated using fused deposition modeling (FDM) with short Lygeum spartum fibers and PLA. Scanning electron microscopy (SEM) was used to analyze fracture surfaces and fiber dispersion within the PLA matrix after mechanical testing. Chemical and thermal properties were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Mechanical performance was assessed through tensile and flexural testing, supplemented by digital image correlation (DIC) and acoustic emission techniques. The incorporation of 10% short natural fibers mitigated the brittle behavior of 3D-printed PLA, resulting in a more ductile biocomposite. These materials exhibited improved mechanical and thermal properties, including increased flexural modulus, higher elongation at break, and enhanced thermal stability compared to neat PLA. These findings underscore the potential of these biocomposites as biodegradable and eco-friendly materials for various applications.

本研究考察了使用熔融沉积建模(FDM)和短Lygeum spartum纤维和PLA制造的3d打印生物复合材料的形态、物理化学、机械和热性能。采用扫描电子显微镜(SEM)对力学测试后的聚乳酸基体的断裂面和纤维分散进行了分析。利用傅里叶红外光谱(FTIR)、热重分析(TGA)和差示扫描量热法(DSC)对其化学和热性质进行了表征。机械性能通过拉伸和弯曲测试进行评估,辅以数字图像相关(DIC)和声发射技术。10%天然短纤维的掺入减轻了3d打印PLA的脆性行为,从而产生更具延展性的生物复合材料。与纯PLA相比,这些材料表现出更好的机械和热性能,包括增加的弯曲模量,更高的断裂伸长率和增强的热稳定性。这些发现强调了这些生物复合材料作为可生物降解和环保材料在各种应用中的潜力。


The electrically controlled dimming film of thiol-vinyl ether system with low-voltage and high contrast ratio for smart windows

Yue Feng, Jianjun Xu, Baohua Yuan, Longxiang He, Luoning Zhang, Yongchuan Hu, Liezheng Lyu, Cheng Zou, Qian Wang, Meina Yu, Yuanwei Chen, Yanzi Gao, Huai Yang

doi:10.1016/j.compositesa.2024.108427

 

智能窗用低电压、高对比度的电控巯基乙烯醚调光膜

As a type of smart window, polymer dispersed liquid crystal (PDLC) electrically controlled dimming film can respond to external electrical stimuli to regulate the optical flux of sunlight, reducing energy consumption. Herein, a PDLC film was prepared by systematically studying the functionalities and structural compatibility of vinyl ether and thiol compounds, and the optimal PDLC film possesses a superior contrast ratio (CR) of 196.9. When the film thickness is adjusted to 8 μm, the film saturation voltage is reduced to 6.7 V, still maintaining a high CR of 48.4. The well-designed PDLC films exhibited excellent modulation of light. The temperature difference between PDLC film and bare ITO glass can reach 4 °C under the simulated sunlight test, demonstrating the good thermal insulation performance. This smart films with low power consumption and high CR can meet the demand for active regulation of optical flux on smart windows.

聚合物分散液晶(PDLC)电控调光膜作为智能窗口的一种,可以响应外界的电刺 激来调节太阳光的光通量,降低能耗。本文通过系统地研究乙烯醚和巯基化合物的功能和结构相容性,制备了PDLC膜,最佳的PDLC膜具有优异的对比度(CR)为196.9。当薄膜厚度调整为8 μm时,薄膜饱和电压降至6.7 V,仍保持48.4的高CR。设计良好的PDLC薄膜具有优异的光调制性能。在模拟日光下,PDLC膜与裸ITO玻璃的温差可达4 ℃,显示出良好的隔热性能。该智能薄膜具有低功耗、高CR的特点,能够满足智能窗口光通量主动调节的需求。


Spatiotemporal prediction of surface roughness evolution of C/C composites based on recurrent neural network

Tong Shang, Jingran Ge, Jing Yang, Maoyuan Li, Jun Liang

doi:10.1016/j.compositesa.2024.108429

基于递归神经网络的C/C复合材料表面粗糙度时空预测

Carbon/carbon (C/C) composites are widely used in aerospace applications due to their excellent properties. Their surface roughness is an important factor affecting the material properties and ablation resistance, which is essential for the accurate prediction of the material. Images are often used to summarize and characterize microstructural features, which include information such as fiber microstructure and fiber orientations. An ablation shape evolution model based on optimization of attention mechanism, which combines multi-scale convolutional neural network (MSCNN) and long short-term memory (LSTM) methods for the C/C composites, is proposed. MSCNN encodes the microstructural information of the ablation image, which is fed into the LSTM model to extract the spatiotemporal features and long-term dependencies latent in the temporal law. The attention mechanism is used to assign different weights to the extracted features which makes the model focus more on the important time steps in the sequence. The results show that the proposed model achieves excellent effects in predicting the evolution of ablative morphology, with high agreement with the simulated values. The method saves time and cost, while providing an efficient and reliable method for the design and optimization of thermal protection materials.

碳/碳(C/C)复合材料由于其优异的性能在航空航天领域得到了广泛的应用。其表面粗糙度是影响材料性能和抗烧蚀性能的重要因素,对材料的准确预测至关重要。图像通常用于总结和表征微观结构特征,其中包括纤维微观结构和纤维取向等信息。结合多尺度卷积神经网络(MSCNN)和长短期记忆(LSTM)方法,提出了一种基于注意机制优化的C/C复合材料烧蚀形状演化模型。MSCNN对消融图像的微结构信息进行编码,并将其输入到LSTM模型中,提取时间规律中隐含的时空特征和长期依赖关系。利用注意机制对提取的特征赋予不同的权重,使模型更加关注序列中重要的时间步长。结果表明,该模型对烧蚀形貌的预测效果较好,与模拟值吻合度较高。该方法节省了时间和成本,同时为热防护材料的设计和优化提供了一种高效可靠的方法。


Preparation and sensing properties of multiscale conductive filler hybrid CNTs@Ag-MXene-TPU/TPU double-layer strain sensing materials

Yanzhi Cai, Dengpeng Chen, Laifei Cheng, Siyu Guo, Zhongyi Hu, Yuhan Wang, Haiming Yu, Yuan Zhou

doi:10.1016/j.compositesa.2024.108430

多尺度导电填料复合CNTs@Ag-MXene-TPU/TPU双层应变传感材料的制备及其传感性能

The performance of sensors is often limited by the structural characteristics of the single form of conductive filler, making it difficult for sensors to simultaneously consider the broad sensing range and high sensitivity. How to achieve high sensitivity and broad working range of sensors through innovative sensing materials and sensor structure design remains a challenge. Here, a flexible sensor with multidimensional sensing materials and a double-layer structure is constructed. It consists of a high-performance CNTs@Ag-MXene-TPU sensing layer and a TPU flexible layer with significant deformability. Thanks to the synergistic effect of the double-layer structure and multidimensional sensing materials, this sensor has a high sensitivity of up to maximum gauge factor of 12216.3 and a wide sensing range of 300 %. Its response time and recovery time can reach 200 and 250 ms, respectively, and it also exhibits excellent cycling stability.

传感器的性能往往受到单一形式导电填料的结构特性的限制,使得传感器难以同时考虑宽的传感范围和高的灵敏度。如何通过创新的传感材料和传感器结构设计来实现传感器的高灵敏度和宽工作范围仍然是一个挑战。本文构建了一种具有多维传感材料和双层结构的柔性传感器。它由高性能CNTs@Ag-MXene-TPU传感层和具有显著可变形性的TPU柔性层组成。由于双层结构和多维传感材料的协同作用,该传感器具有高灵敏度,最大测量因子可达12216.3,传感范围可达300 %。其响应时间和恢复时间可分别达到200和250 ms,并具有良好的循环稳定性。


Composites Part B: Engineering

Predicting damping in geometrically complex composite structures via increased interlaminar homogenisation

T. Mace, C.W. Schwingshackl

doi:10.1016/j.compositesb.2024.111769

通过增加层间均匀化预测几何复杂复合结构中的阻尼

The widespread adoption of composite materials across the engineering sector requires that the vibration behaviour of these materials is more readily taken into account for new component designs. Current prediction methods are often prohibitively complex or expensive for such applications, or are restricted to very simple geometries. A simplified approach, shown previously by the authors to generate accurate and inexpensive predictions, is extended to geometrically more complex test cases in this work. The novel technique is shown to hold up well compared to the more established ‘layered’ approach, outperforming such predictions in some cases and highlighting the general applicability of the approach for damping predictions in general composite components.

复合材料在工程领域的广泛应用,要求在设计新部件时更容易考虑到这些材料的振动特性。当前的预测方法对于此类应用来说通常过于复杂或昂贵,或者仅限于非常简单的几何形状。作者先前展示的一种简化的方法可以生成准确且廉价的预测,在这项工作中被扩展到几何上更复杂的测试用例。与更成熟的“分层”方法相比,新技术表现良好,在某些情况下优于此类预测,并突出了该方法在一般复合材料部件阻尼预测中的普遍适用性。


Impact characteristics of S2-glass fibre/FM94-epoxy composites under high and cryogenic temperatures: experimental and numerical investigation

Ahmad S.M. Al-Azzawi, C.A. Featherston, Colin Lupton, Chulin Jiang, Antigoni Barouni, Ugur Koklu, Khaled Giasin

doi:10.1016/j.compositesb.2024.111786

高温和低温下s2 -玻璃纤维/ fm94 -环氧复合材料的冲击特性:实验和数值研究

The aerospace industry uses glass fibre reinforced polymer (GFRP) composites to manufacture structural and non-structural parts of an aircraft as they possess superior strength to weight ratio and exceptional corrosion resistance. Commercial aircraft operate in a very wide temperature ranges from -54 to 55 °C. Potential GFRP laminates are susceptible to impact during aircraft operation, and the temperature at impact governs the nature of damage and failure mechanisms. As a result, the current study focuses on examining how aeronautical GFRP composites behave in various temperature environments that are encountered during high- and low-altitude operations. Using S2-glass fibre/FM94-epoxy unidirectional prepreg, GFRP plates were created. Drop weight impact tests were conducted at ambient (25 °C), high (50, 75, 100 °C), and low (-25, -55 °C) temperatures, as well as at various impact energies (75, 150, 225 J). The damages were assessed visually, along with their sizes. Each testing scenario's impact parameters, including the impact load, deflection, and energy absorption, were also examined. In Abaqus/Explicit, a coupled temperature-displacement numerical model was created to predict the onset of stress and damage. According to experimental findings, GFRP plates are stiffer and show less apparent damage at cryogenic temperatures (∼15-34% lower displacement) than they do at other temperatures. Furthermore, it was observed that the matrix softens at high temperatures, showing larger damaged area at entry but with less obvious damage and increasing energy absorption, while semi-perforation occurred under cryogenic temperatures at entry with smaller damaged area. A strong correlation is shown between the experimental and FE data, confirming the capability of FE models to predict impact damage and deflections at different temperatures in the future.

航空航天工业使用玻璃纤维增强聚合物(GFRP)复合材料制造飞机的结构和非结构部件,因为它们具有优越的强度重量比和卓越的耐腐蚀性。商用飞机的工作温度范围很宽,从-54°C到55°C。潜在的玻璃钢层压板在飞机运行过程中容易受到冲击,冲击时的温度决定了损伤和失效机制的性质。因此,目前的研究重点是研究航空GFRP复合材料在高空和低空作业中遇到的各种温度环境下的性能。采用s2 -玻璃纤维/ fm94 -环氧单向预浸料制备GFRP板材。在环境温度(25°C)、高温度(50、75、100°C)和低温度(-25、-55°C)以及不同的冲击能量(75、150、225 J)下进行了落锤冲击试验。每个测试场景的冲击参数,包括冲击载荷、挠度和能量吸收,也进行了检查。在Abaqus/Explicit中,建立了温度-位移耦合数值模型来预测应力和损伤的发生。根据实验结果,GFRP板在低温下比在其他温度下更硬,表现出更少的明显损伤(位移降低~ 15-34%)。此外,观察到高温下基体软化,在进入时损伤面积较大,但损伤不明显,能量吸收增加,而在低温下进入时发生半穿孔,损伤面积较小。实验数据与有限元数据之间存在很强的相关性,证实了有限元模型在未来不同温度下预测冲击损伤和挠度的能力。


Full-color, Highly Bright and Stretchable Electroluminescent Device with Janus Colors Based on Photoluminescent Electrode for Wireless Dynamical Display

Zupeng Liu, Hao Yang, Haiyuan Yuan, Yuliang Cheng, Bingang Xu, Ming Xue, Titao Jing

doi:10.1016/j.compositesb.2024.111787

基于光致发光电极的无线动态显示全彩色、高亮度、可拉伸双色电致发光器件

Stretchable displays are essential for the upcoming era of flexible electronics as they are the foundation of interactive human–machine interface. To date, alternating current electroluminescent (ACEL) devices are regarded as one of the most practicable routes for stretchable displays but their colors are very limited for the demand of full-color displays. Herein, we developed an ACEL device with Janus and full color through photoluminescent electrodes. In the front of the devices, multiple colors are achieved, Red, Blue, Green, and Yellow, covering a 66% National Television System Committee color gamut. In the back, mixed lights of White, Purple, and Cyan color are obtained, enabling devices with Janus colors. The brightness enhancement of highly desirable white light achieves 4.4-fold, which is also one of the best performances. Our strategy exploits the indispensable electrode for ACEL and avoids structural changes, endowing the devices with a much better stretchability and brightness as compared to traditional methods. Moreover, our strategy is a general method that is applicable to different stretchable ACEL devices. A wearable device of 8*8 pixels is assembled and can dynamically display information from smart phones through Bluetooth in real time, laying a considerable advancement towards stretchable displays with full color.

可拉伸显示器是即将到来的柔性电子时代必不可少的,因为它们是交互式人机界面的基础。迄今为止,交流电致发光(ACEL)器件被认为是可拉伸显示最可行的途径之一,但其颜色对于全彩显示的需求非常有限。在此,我们通过光致发光电极开发了具有双面和全彩的ACEL装置。在设备的前面,实现了多种颜色,红,蓝,绿,黄,覆盖66%的国家电视系统委员会色域。在背面,获得白色,紫色和青色的混合光,使设备具有双面神色。非常理想的白光亮度增强达到4.4倍,这也是最好的性能之一。我们的策略利用了ACEL不可缺少的电极,避免了结构变化,使器件具有比传统方法更好的拉伸性和亮度。此外,我们的策略是一种通用的方法,适用于不同的可拉伸ACEL设备。组装出8*8像素的可穿戴设备,通过蓝牙实时动态显示智能手机信息,向可拉伸全彩显示方向迈进了一大步。


Composites Science and Technology

Damage identification of plain-woven composites at T > Tg using AE: damage clustering and initiation detection

Hao Lu, Tao Zheng, Li Zhang, Kai Huang, Xiaodong Liu, Xiaojian Han, Yue Wang, Licheng Guo

doi:10.1016/j.compscitech.2024.110823

 

用声发射识别T > Tg平面编织复合材料的损伤:损伤聚类和起爆检测

In this work, the damage modes and their initiation detections of plain-woven composites under tensile and compressive loads at T > Tg are investigated by conducting a comprehensive analysis of AE signals, including the feature selection, algorithm comparison and clustering validity. According to a newly proposed Pearson correlation coefficient cumulative criterion, the PF and PA are the most representative features of AE signals. A systematic comparison of K-Means, GMM and Hierarchical model, reveals that the Hierarchical model is the most suitable clustering algorithm for plain-woven composites at T > Tg. The cluster validity indexes combined with microscopic observations identify matrix cracking, interface debonding and fiber breakage as the three dominant damage modes, with PF ranges of [0-200 kHz], [200-350 kHz] and [350-600 kHz], respectively, and independent of different loading conditions. Three damage initiation criteria, sentry function, b-value and cumulative AE counts, are compared and the sentry function is determined to be optimal. The damage initiations of matrix cracking, interface debonding and fiber breakage within plain-woven composites at T > Tg can be effectively detected by AE.

本文通过对声发射信号的综合分析,包括特征选择、算法比较和聚类有效性,研究了T > Tg的拉伸和压缩载荷作用下平纹编织复合材料的损伤模式及其起裂检测。根据新提出的Pearson相关系数累积准则,波峰和波峰是声发射信号最具代表性的特征。通过对K-Means、GMM和Hierarchical模型的系统比较,发现在T > Tg时,Hierarchical模型是最适合的聚类算法。结合微观观察,聚类有效性指标确定基体开裂、界面脱粘和纤维断裂是三种主要的损伤模式,其PF范围分别为[0 ~ 200 kHz]、[200 ~ 350 kHz]和[350 ~ 600 kHz],且与不同加载条件无关。通过对哨兵函数、b值和累积声发射计数三种损伤起爆准则的比较,确定哨兵函数为最优。在T > Tg时,声发射可以有效地检测到复合材料内部基体开裂、界面剥离和纤维断裂的损伤起始。


Liquid metal Induced segregated-like Electromagnetic Shielding composites with Excellent Photothermal conversion and Strain Sensing Capacities

Lijuan Qiu, Wanlin Han, Qinglong Yu, Yijun Liu, Baoshu Chen, Longfei Yi

doi:10.1016/j.compscitech.2024.110825

 

具有优异光热转换和应变传感能力的液态金属诱导类偏析电磁屏蔽复合材料

The development of multifunctional electromagnetic interference (EMI) shielding materials has garnered significant attention, yet achieving flexible composites that integrate EMI shielding, thermal conductivity, and other functionalities under low filler loading remains a challenge. This study presents a novel flexible composite with segregated structure prepared via a simple co-mixing and hot-pressing method. By selectively distributing conductive Liquid metal (LM) and Multi-wall carbon nanotube (CNT) on the surface of Polyurethane (TPU) particles, a continuous and compact conductive network is successfully constructed, enabling the attainment of a high EMI shielding effectiveness of 80.2 dB and a thermal conductivity of 4.8 W m-1 K-1 even at low LM loadings. Furthermore, the composite exhibits low-voltage-driven Joule heating performance, excellent photothermal conversion efficiency, and promising potential for wearable sensor applications. The combination of these outstanding properties highlights the great potential of LM-based composites for next-generation wearable devices.

多功能电磁干扰(EMI)屏蔽材料的开发已经引起了极大的关注,然而,在低填料负载下实现集成EMI屏蔽、导热性和其他功能的柔性复合材料仍然是一个挑战。采用简单的共混热压法制备了一种具有分离结构的新型柔性复合材料。通过选择性地将导电液态金属(LM)和多壁碳纳米管(CNT)分布在聚氨酯(TPU)颗粒表面,成功构建了连续紧凑的导电网络,即使在低LM负载下,也能获得80.2 dB的高EMI屏蔽效能和4.8 W m-1 K-1的导热系数。此外,该复合材料具有低电压驱动的焦耳加热性能,出色的光热转换效率,在可穿戴传感器应用中具有广阔的潜力。这些卓越性能的结合凸显了lm基复合材料在下一代可穿戴设备中的巨大潜力。


Lightweight and compressible PANI/Ti3C2Tx/EVA composite foam for tunable microwave absorption

Zimo He, Yiyuan Shi, Huiya Wang, Yaofeng Zhu

doi:10.1016/j.compscitech.2024.110826

 

轻质可压缩PANI/Ti3C2Tx/EVA复合泡沫可调微波吸收

Dynamic deformation and absorbing regulation are still challenging for designing lightweight and high-efficiency microwave absorbing materials, which are of great indispensability to satisfy changeable and complex electromagnetic environments. Herein, a compressible composite foam with sea-island structure was prepared by loading porous polyaniline (PANI)/Ti3C2Tx composites on ethylene/vinyl acetate (EVA) skeleton via a thermally induced phase separation strategy. The composite foam exhibits a minimum reflection loss (RLmin) of –57.84 dB and an effective absorption bandwidth (EAB, RL ≤ −10 dB) of 1.86 GHz (8.2–10.05 GHz) at 3.4 mm. Notably, the microwave absorption (MA) performance can be precisely regulated by simply adjusting the compression ratio of composite foam. The RL peaks shift towards higher frequencies with increasing compression ratios, originating from changes in the internal conductive network. Even under 30 % compression strain, the composite foam still maintains RLmin of –21.53 dB and broadens EAB up to 2.71 GHz at 2.0 mm. This combination of compression capabilities and dynamically tunable MA performance may expand a novel approach to designing multifunctional polymer-based foam.

动态变形和吸波调节仍是设计轻质高效微波吸波材料的挑战,对于满足多变复杂的电磁环境不可或缺。本文通过热诱导相分离策略,在乙烯/醋酸乙烯(EVA)骨架上负载多孔聚苯胺(PANI)/Ti3C2Tx复合材料,制备了具有海岛结构的可压缩复合泡沫。复合泡沫的最小反射损耗(RLmin)为 -57.84 dB,在 3.4 mm 时的有效吸收带宽(EAB,RL ≤ -10 dB)为 1.86 GHz(8.2-10.05 GHz)。值得注意的是,只需调整复合泡沫的压缩比,就能精确调节微波吸收(MA)性能。随着压缩比的增加,RL 峰值会向更高的频率移动,这源于内部导电网络的变化。即使在 30% 的压缩应变下,复合泡沫仍能保持 -21.53 dB 的 RLmin,并在 2.0 mm 时将 EAB 扩大到 2.71 GHz。这种压缩能力与动态可调 MA 性能的结合,为设计基于聚合物的多功能泡沫提供了一种新方法。




来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalSystem振动断裂复合材料化学拓扑优化通用航空航天汽车电子裂纹电场理论材料多尺度
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【新文速递】2024年8月28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 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresNumerical assessment of fiber distribution effects on strain-hardening cement composites using a rate-dependent Voronoi-Cell-Lattice-ModelJi Woon Park, Bonhwi Choo, Jeongun Lee, Yun Mook Limdoi:10.1016/j.compstruct.2024.118515基于速率相关Voronoi-Cell-Lattice-Model的纤维分布对应变硬化水泥复合材料影响的数值评估Strain-hardening cementitious composites, also known as high-performance fiber-reinforced cementitious composites, display exceptional strength and toughness not only under static conditions but also under high-speed dynamic loading. The mechanical properties of these composites are greatly influenced by the orientation and dispersion of embedded fibers. However, experimental analysis of complex fiber arrangements in real specimens has limitations, necessitating the development of computational models to understand the impact of fiber distribution. This study examines the effect of fiber distribution conditions on composite behavior using a Voronoi-Cell-Lattice-Model that incorporates reinforcing effects into discrete-type quasi-brittle matrix elements. Firstly, virtual fiber distribution models revealed that as the gauge length of specimens increased, weaknesses in fiber distribution were more likely to form, leading to decreased strength and strain capacity. Secondly, the model demonstrated that favorable fiber orientation relative to the loading direction and minimal sectional deviation in fiber dispersion significantly increased strain capacity and toughness. Finally, the study explored the wall-effect that may arise during specimen fabrication due to the boundary of the casting mold.应变硬化胶凝复合材料,也被称为高性能纤维增强胶凝复合材料,不仅在静态条件下,而且在高速动态载荷下都表现出优异的强度和韧性。包埋纤维的取向和分散对复合材料的力学性能有很大影响。然而,对真实样品中复杂纤维排列的实验分析存在局限性,需要开发计算模型来了解纤维分布的影响。本研究使用Voronoi-Cell-Lattice-Model来检验纤维分布条件对复合材料性能的影响,该模型将增强效应纳入离散型准脆性基体元素中。首先,虚拟纤维分布模型表明,随着试件规范长度的增加,纤维分布的弱点更容易形成,从而导致强度和应变能力下降。其次,该模型表明,相对于加载方向有利的纤维取向和纤维分散的最小截面偏差显著提高了应变能力和韧性。最后,研究探讨了由于铸型边界在试样制作过程中可能产生的壁效应。Transient thermal fracture analysis of a honeycomb layer with a central crackWenzhi Yang, Zengtao Chendoi:10.1016/j.compstruct.2024.118518含中心裂纹蜂窝层的瞬态热断裂分析Auxetic honeycomb materials with negative Poisson’s ratio received rapidly growing attention in recent years owing to their exceptional thermomechanical properties in constructing sandwich composites. The objective of this article is to investigate the transient thermal behavior and fracture risk of a honeycomb layer with a central crack subject to a sudden thermal shock by theoretical modeling. Two different material configurations along both orthogonal directions, as well as the conventional and auxetic hexagonal alumina honeycomb cells, are examined to illustrate their effects on the thermal stress intensity factors. To solve the thermoelastic governing equations subject to complex boundary conditions, the methodology of integral transform with singular integral equation is employed. The numerical results demonstrate that the auxetic honeycombs can reduce the thermal stress intensity factors significantly compared to their conventional counterparts. The ratio of stress intensity factors in auxetic to non-auxetic honeycombs under the same absolute value of the internal cell angle θ decreases monotonically with increasing |θ|. In addition, the effects of the relative density, crack length, and crack position are investigated. Our findings would provide a more comprehensive understanding of the honeycomb’s fracture behaviors and contribute to the material design of the sandwich composites with honeycomb cores.负泊松比辅助蜂窝材料由于其在构建夹层复合材料中具有优异的热力学性能,近年来受到越来越多的关注。本文的目的是通过理论建模研究中心裂纹蜂窝层在突然热冲击作用下的瞬态热行为和断裂风险。研究了正交方向上两种不同的材料结构,以及常规和非对称六方氧化铝蜂窝电池,以说明它们对热应力强度因子的影响。为求解复杂边界条件下的热弹性控制方程,采用奇异积分方程的积分变换方法。数值结果表明,与传统蜂窝相比,辅助蜂窝能显著降低热应力强度因子。在相同胞内角θ绝对值下,随|θ|的增大,消声与非消声蜂窝的应力强度因子之比单调减小。此外,还研究了相对密度、裂纹长度和裂纹位置的影响。本研究结果将为蜂窝的断裂行为提供更全面的认识,并有助于蜂窝芯夹层复合材料的材料设计。Multiscale fatigue life prediction model for CFRP laminates considering the mechanical degradation of its constituents and the local stress concentration of the matrixJeong Hwan Kim, Dongwon Ha, Hoil Choi, Gun Jin Yundoi:10.1016/j.compstruct.2024.118519考虑构件力学退化和基体局部应力集中的CFRP复合材料多尺度疲劳寿命预测模型In the present research, a novel approach for predicting the fatigue life of composites is proposed using a multiscale fatigue model. This model considers two critical physical phenomena that occur in CFRP laminates under tension-tension cyclic loading – the degradation of the physical properties of CFRP constituents and the localized stress concentrations within the matrix. To achieve this, Mori-Tanaka’s mean field theory, a well-known micromechanics model, is employed to consider the deterioration of material properties in various phases, which is dependent on the applied stress level. Localized stress concentration phenomena within the matrix of a composite material are common when CFRP laminate is subjected to cyclic loading. The localized stress concentration on a matrix with different numbers of fibers and orientations using representative volume elements (RVE) is investigated. Two other scales of failure criteria are defined to evaluate its constituent at the material level and ply level at the macroscale. A comparison with fatigue experiment data of AS4/3501-6 composite shows good reliability of the proposed multiscale fatigue model.本研究提出了一种利用多尺度疲劳模型预测复合材料疲劳寿命的新方法。该模型考虑了CFRP层压板在拉伸-拉伸循环载荷下发生的两个关键物理现象——CFRP成分物理性能的退化和基体内的局部应力集中。为了实现这一点,Mori-Tanaka的平均场理论,一个著名的微观力学模型,被用来考虑材料性能在不同阶段的恶化,这取决于施加的应力水平。复合材料复合材料在循环荷载作用下,基体内部存在局部应力集中现象。利用代表性体积元(RVE)研究了不同纤维数和取向的基体上的局部应力集中。定义了另外两个尺度的破坏准则,分别在材料水平和层数水平上对其成分进行评价。与AS4/3501-6复合材料的疲劳试验数据对比表明,所提出的多尺度疲劳模型具有良好的可靠性。Modified mode I fracture toughness calculation method for composite laminate with large scale fiber bridgingQingfeng Duan, Haixiao Hu, Dongfeng Cao, Wei Cai, Junkang Xia, Shuxin Lidoi:10.1016/j.compstruct.2024.118521大型纤维桥接复合材料层合板的修正I型断裂韧性计算方法Experimental investigation and theoretical analysis have been carried out in this study to assess the application limitation of the current ASTM D5528 method for Mode I fracture toughness calculation of composite laminate with fiber bridging. It is revealed that additional toughening effect introduced by the fiber bridging is not fully considered in the current method and consequently there are uncertainties associated with the fracture toughness calculated by the current ASTM method. Based on the same principle used in the development of the original ASTM method, a modified method is proposed to extend the applicability of the current method. The modified method is verified with mechanisms based cohesive zone modelling and numerical simulations of the Mode I delamination double cantilever beam tests. The significant improvement of the prediction results compared with experimental results by the modified method over the current method demonstrated its applicability for Mode I delamination fracture toughness calculation of composite laminates with large scale fiber bridging.本研究通过实验研究和理论分析来评估现行ASTM D5528方法在纤维桥接复合材料层合板I型断裂韧性计算中的应用局限性。结果表明,目前的方法没有充分考虑纤维桥接带来的额外增韧效应,因此现行ASTM方法计算的断裂韧性存在不确定性。在与原ASTM方法发展的原理相同的基础上,提出了一种改进的方法,以扩大现有方法的适用性。通过基于力学的内聚区建模和I型脱层双悬臂梁试验的数值模拟,验证了改进方法的有效性。修正后的方法预测结果与实验结果相比有明显改善,表明该方法适用于大规模纤维桥接复合材料层合板的I型分层断裂韧性计算。Composites Part A: Applied Science and ManufacturingEnhancing interfacial performance and fracture toughness of carbon fibre reinforced thermoplastic compositesYao Chen, Vishnu Prasad, Miray Yasar, Neal Murphy, Alojz Ivankovicdoi:10.1016/j.compositesa.2024.108434 提高碳纤维增强热塑性复合材料的界面性能和断裂韧性Enhancing the interlaminar fracture toughness of composites significantly improves their load bearing capacity and structural integrity over longer service life by improving their resistance to delamination. The effect of hybrid toughening of Elium-based thermoplastic composites involving polydopamine (PDA), multi-walled carbon nanotubes (MWCNTs) sizing, and polyphenylene sulfide (PPS) veil interlayers was investigated to observe the mechanical response using 3-point bending, interlaminar shear strength, and Mode I fracture toughness tests. The enhancement of fibre–matrix adhesion contributed to improvements in both flexural strength and interlaminar shear strength, while additional toughening mechanisms, such as PDA bridging, PPS pull-out and breakage, and fibre bridging, enhanced the Mode I interlaminar fracture toughness by 218%.提高复合材料的层间断裂韧性,通过提高复合材料的抗分层能力,显著提高复合材料的承载能力和结构完整性,延长复合材料的使用寿命。通过3点弯曲、层间剪切强度和I型断裂韧性测试,研究了聚多巴胺(PDA)、多壁碳纳米管(MWCNTs)和聚苯硫醚(PPS)复合材料杂化增韧的效果。纤维基质粘附性的增强有助于提高弯曲强度和层间剪切强度,而额外的增韧机制,如PDA桥接、PPS拔出和断裂以及纤维桥接,使I型层间断裂韧性提高了218%。Composites Part B: EngineeringStretch-Steering of Highly Aligned Discontinuous Fiber Tape with Automated Fiber PlacementAlexander Legenstein, Lukas Fussel, Dirk Heider, John W. Gillespie, Thomas A. Cenderdoi:10.1016/j.compositesb.2024.111801 高度对准不连续纤维带自动铺布的拉伸控制Highly aligned discontinuous fiber (ADF) composites have been developed with mechanical properties comparable to continuous fiber composites. These materials can be stretched in the fiber direction during processing enabling the production of complex geometries. This study utilizes 57% fiber volume fraction ADF tape comprised of a thermoplastic Polyetherimide (PEI) matrix with 3 mm long IM7 carbon fibers. The Laser-Assisted Automated Fiber Placement (LA-AFP) process is used to study the limits of stretch-steering of ADF tape at small radii. An experimental technique based on photogrammetry was developed to quantify the effect of stretch parameters on the tape strain fields and path placement accuracy. The measurements captured the local in-plane strain tensor (longitudinal, transverse, and shear) across the width and along the length of steered tapes. The results demonstrate that placement path accuracy can be achieved when the tool center point (center of rotation) of the AFP head is located at the nip-point versus the roller centerline, which is typically used for steering continuous fiber tapes at large steering radii. Accuracy of the in-situ tape stretching was demonstrated up to 60% applied stretch strain. The measurements also confirm that when stretch-steering ADF tape, the resulting strain across the tape width is on average the superposition of the in-situ applied tensile strain and in-plane bending computed from the tape width and steering radius. A statistical-based methodology is presented to select the average tensile stretch levels to minimize the probability of defects forming during steering on the inner radius of the tape. The experiments show that a 12.5 mm wide tape can be accurately placed on a 50 mm radius of curvature without defects. This represents a two order of magnitude improvement in steerability over continuous fiber tapes of the same tape width found in peer-reviewed literature.高度排列的不连续纤维(ADF)复合材料具有与连续纤维复合材料相当的力学性能。这些材料可以在加工过程中向纤维方向拉伸,从而生产出复杂的几何形状。本研究使用由热塑性聚醚酰亚胺(PEI)基体和3mm长的IM7碳纤维组成的纤维体积分数为57%的ADF胶带。采用激光辅助自动铺放光纤(LA-AFP)工艺研究了ADF胶带在小半径处的拉伸转向极限。提出了一种基于摄影测量的实验技术,以量化拉伸参数对胶带应变场和路径放置精度的影响。测量捕获了局部平面内应变张量(纵向、横向和剪切),沿着导向胶带的宽度和长度。结果表明,当AFP头的工具中心点(旋转中心)位于夹尖点而不是滚轮中心线时,可以实现放置路径精度,这通常用于在大转向半径下转向连续纤维带。原位胶带拉伸的精度可达60%的拉伸应变。测量结果还证实,当拉伸导向ADF胶带时,在胶带宽度上产生的应变是现场施加的拉伸应变与根据胶带宽度和导向半径计算的平面内弯曲的平均叠加。提出了一种基于统计的方法来选择平均拉伸水平,以尽量减少在胶带内半径上转向过程中形成缺陷的概率。实验表明,12.5 mm宽的胶带可以精确地放置在半径为50 mm的曲率上而没有缺陷。与同行评议文献中发现的相同磁带宽度的连续光纤磁带相比,这代表了两个数量级的可操作性改进。Composites Science and TechnologyUnlocking thermal management capacity: Optimized organic-inorganic hybrid shell phase change microcapsules with controllable structure and enhanced conductivityXueting Wang, Huaxin Chen, Dongliang Kuang, Xiao Huan, Zhengyuan Zeng, Cong Qi, Shanjian Han, Guanyu Lidoi:10.1016/j.compscitech.2024.110836 解锁热管理能力:优化结构可控、电导率增强的有机-无机杂化壳相变微胶囊Microencapsulated phase change material (MPCM) stands as a strong candidate for temperature control of thermal management systems in broad fields like building construction. A novel design strategy for hybridized shell-based MPCM (HMPCM) containing methyl methacrylate (MMA) and silica was developed by the interfacial hydrolysis-condensation method, with characteristics of controllable structure and enhancement in the interaction between the polymer and inorganic thermal conductivity additives. Two hybridized shell structures, including a homogeneous structure and another unique porous cavity structure shaped like a foam, can be obtained by adjusting for preparation conditions. The results reveal that the thermal conductivity is significantly enhanced by hybridized shells compared to pure MMA shells, with a dramatic increment of 92.16%. Therefore, a highly satisfactory microcapsule material characterized by superior thermal conductivity and energy storage efficiency exceeding 99.9% was fabricated. The results of thermal cycling reliability assessments underscore the favorable attributes of microcapsules, encompassing stable charging/discharging behavior, exceptional phase change reversibility, and prompt thermal responsiveness. Moreover, the feasibility of microcapsules in building thermal management applications has been verified. The temperature difference of 10.3 °C between the matrix with and without microcapsules demonstrates the capability of HMPCMs to effectively regulate the temperature of the surrounding environment. Consequently, these newly developed HMPCMs reinforced by hybridized shells are promising thermoregulation materials for thermal management systems that await further applications.微封装相变材料(MPCM)是建筑施工等广泛领域热管理系统温度控制的有力候选材料。采用界面水解-缩合的方法,提出了一种新型的含甲基丙烯酸甲酯(MMA)和二氧化硅的杂化壳基MPCM (HMPCM)的设计策略,该策略具有结构可控和增强聚合物与无机导热添加剂相互作用的特点。通过调整制备条件可得到两种杂化壳结构,包括均匀结构和另一种独特的泡沫状多孔腔结构。结果表明,与纯MMA壳层相比,杂化壳层的导热系数显著提高,增幅达92.16%。因此,制备了一种导热性能优异、储能效率超过99.9%的令人满意的微胶囊材料。热循环可靠性评估的结果强调了微胶囊的优点,包括稳定的充放电行为、异常的相变可逆性和快速的热响应性。此外,还验证了微胶囊在建筑热管理应用中的可行性。带微胶囊和不带微胶囊的基质温差为10.3℃,表明hmpcm能够有效调节周围环境温度。因此,这些新开发的杂化壳增强的hmpcm是热管理系统中有前途的热调节材料,有待进一步应用。来源:复合材料力学仿真Composites FEM

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