今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 3 篇
Vibration characteristics and response behaviors of three-dimensional-four-directional knitted composite sandwich cylindrical shells with pyramidal latticed cellular cores
Bocheng Dong, Kaiping Yu, Rui Zhao
doi:10.1016/j.compstruct.2024.118582
具有锥体网格芯的三维四向编织复合材料夹层圆柱壳的振动特性及响应行为
Responding to the stringent lightweight and mechanical performance requirements of aerospace vehicle devices, a novel sandwich cylindrical shell structure with three-dimensional-four-directional knitted composite skins and pyramidal latticed cellular cores is tailored as a well-optioned scheme for the critical components. A desired dynamic model of the goal structure under free and forced vibration occasions is proposed first as a prediction tool for coping with the existing lack, and the virtual spring technique is filled in the developed model to extend arbitrary boundary conditions. In the framework of the theoretical formulations constructed, explicit expressions for the effective mechanical properties of spatially knitted composite skins and cellular cores are derived. Afterwards, the first-order shear deformation shell theory and Jacobi-Ritz approach are utilized to deduce energy expressions, and the mode shapes, inherent frequencies, response amplitude, and decay signature are solved by adopting the eigenvalue and Newmark-Beta techniques. Compliant model parameters with low running costs and guaranteed calculation precision are given in convergence analyses, which pave the path for efficient data output and numerical calibration. After undertaking the model validation work, the impact laws of key variables on the dynamic indicators are released, with some contributions being made conducive to upgrading the vibration resistance capabilities.
针对航空航天飞行器对轻量化和力学性能的严格要求,设计了一种新型的夹层圆柱壳结构,该结构具有三维四向针织复合材料蒙皮和锥体网格蜂窝芯,是关键部件的优选方案。首先提出了目标结构在自由振动和强迫振动情况下的理想动力学模型,作为一种预测工具,弥补了现有的不足,并在所建立的模型中填充了虚拟弹簧技术,扩展了任意边界条件。在构建的理论公式框架内,导出了空间编织复合材料表皮和蜂窝芯的有效力学性能的显式表达式。然后,利用一阶剪切变形壳理论和Jacobi-Ritz方法推导能量表达式,采用特征值和Newmark-Beta技术求解模态振型、固有频率、响应幅值和衰减特征。在收敛分析中给出了运行成本低、计算精度有保证的模型参数,为有效的数据输出和数值标定铺平了道路。在承担了模型验证工作后,发布了关键变量对动力指标的影响规律,为提升抗振能力做出了一定贡献。
Study on stable configurations and snap through of the rectangular VS bi-stable laminates with curvilinear fiber alignment
C.C. Wu, Y.X. Hao, W. Zhang
doi:10.1016/j.compstruct.2024.118588
曲线纤维对中矩形VS双稳态层合板的稳定构型及通断研究
With advances in fiber placement technology, variable stiffness bistable laminates (VSBL) composited by curvilinear fiber format become a subject of intense interest for morphing structures due to their lower weight, adjustable stiffness and a richer range of stable configurations compared to straight fiber bistable laminate. Merely conducting research on square laminates is not enough allowing for practical application scenarios. This article investigates the influence of geometrical parameters of VSBL on the stable state configuration and static snap through actuated by MFC systematically. A quadratic variable curvature polynomial is used to fit the transverse displacement according to classical laminate theory. By means of von-Karman geometrical relationship and the Rayleigh-Ritz method, stable configurations of the VS bistable laminate are solved. By comparing with finite element results, the reliability and precision of the current results are verified. It shows that changing fiber orientation leads to significant effects on the steady state configuration and critical bifurcation points. Theoretical analysis of VS bistable laminates containing the smart piezoelectric material MFC is followed by analytical modeling. The voltage threshold required for actuating snap through of two stable states is acquired by smart material layer MFC. The specific reasons for the differences in the configurations of VS bistable laminates are illustrated by analyzing distribution of the stiffness of VSBL in the plane.
随着纤维铺层技术的进步,曲线纤维复合的变刚度双稳态层压板(VSBL)由于其较直纤维双稳态层压板具有更轻的重量、可调的刚度和更丰富的稳定结构范围而成为变形结构研究的热点。仅仅对方形层压板进行研究是不够的,考虑到实际应用场景。本文系统地研究了由MFC驱动的VSBL的几何参数对其稳态结构和静态断裂的影响。根据经典层叠理论,采用二次变曲率多项式拟合横向位移。利用von-Karman几何关系和Rayleigh-Ritz方法,求解了VS双稳态层压板的稳定构型。通过与有限元计算结果的比较,验证了现有计算结果的可靠性和精度。结果表明,改变光纤取向对光纤的稳态结构和临界分岔点有显著影响。对含有智能压电材料MFC的VS双稳态层合板进行了理论分析,并进行了解析建模。通过智能材料层MFC获取两种稳定状态触发断通所需的电压阈值。通过分析VSBL在平面内的刚度分布,阐述了VS双稳层板构型差异的具体原因。
Modeling of multi-scale 3-D conductive network and electrical conductivity of carbon fiber braided composites
Yousong Xue, Zhiyong Li, Gen Li, Xin Xu, Jun Ding, Bohong Gu, Baozhong Sun
doi:10.1016/j.compositesa.2024.108479
碳纤维编织复合材料多尺度三维导电网络及导电性建模
The prediction of electrical conductivity and current conduction path of carbon fiber 3-D braided composites is challenging due to its complex microstructure. This paper presents a modeling approach for establishing the multi-scale 3-D conductive network to study the current conduction behavior of the braided composites. The real microstructures, including the random distribution and random contact of carbon fibers at the micro-scale, the spatial path of carbon fiber yarn, and the yarn contact at the meso-scale, have been considered in the model. The conductive network models are valid for the conductivity prediction of the yarn and the composites. The electric potential distribution and current conduction path inside the yarn and the composites have been obtained with the multi-scale 3-D conductive network. This work provides a modeling method with high computational efficiency and simple implementation to quickly predict and design the conductivity of 3-D braided composites.
碳纤维三维编织复合材料由于其复杂的微观结构,其电导率和电流传导路径的预测具有一定的挑战性。本文提出了一种建立多尺度三维导电网络的建模方法,用于研究编织复合材料的电流传导行为。模型考虑了碳纤维在微观尺度上的随机分布和随机接触、碳纤维纱线的空间路径以及纤维在中观尺度上的接触等真实微观结构。所建立的导电网络模型对纱线和复合材料的电导率预测是有效的。利用多尺度三维导电网络得到了纱线和复合材料内部的电势分布和电流传导路径。为三维编织复合材料电导率的快速预测和设计提供了一种计算效率高、实现简单的建模方法。
Performance-Tunable Thermal Barrier Coating for Carbon Fiber-Reinforced Plastic Composite Materials via Flame Spraying
Heejin Kim, Kandasamy Praveen, Min Wook Lee, Juhyeong Lee
doi:10.1016/j.compositesb.2024.111842
碳纤维增强塑料复合材料火焰喷涂性能可调热障涂层研究
Thermal barrier coatings (TBCs) are essential for improving the heat resistance of materials operating in high-temperature environments. This paper proposes a new method for manufacturing double-layered TBC with graded porosity for carbon fiber-reinforced plastic (CFRP) composites. The TBC was created by a flame spraying process, consisting of relatively dense and porous layers: (1) a dense layer was produced by spraying yttria-stabilized zirconia (YSZ) particles directly onto neat carbon fabric substrate and (2) a porous layer was prepared by co-spraying YSZ particles with sacrificial polyetheretherketone (PEEK) particles. The porosity of the porous layer was controlled by varying a PEEK injection distance (D) and a PEEK feed rate (R). The correlation between porosity and thermal conductivity of the TBC layer was investigated to assess its thermal barrier performance. The TBC was fabricated with the D of 5 cm and the R of 1.0 g/min, and double-layered/CFRP composites were manufactured using partially cured CFRP and vacuum forming. The 660-μm-thick TBC with 34% porosity and 0.27 W/m∙K thermal conductivity protected the CFRP substrate remarkably under the subjected torch at 500°C, as the TBC layer reduced the surface temperature of CFRP beyond (TCFRP) 230°C. Thermomechanical analysis, following thermal shock tests, revealed that the double-layered TBC/CFRP composite retained 87% and 75% of its pristine flexural strength and modulus, respectively, while the neat CFRP composite was completely burnt out. This study explored the application of flame spray technology to develop highly effective double-layered TBCs with tunable porosity to maximize their thermal barrier performances. All results from the current study provide new insights into the design and development of CFRP composites and, by extension, TBCs for fiber composites, which will benefit a wide range of lightweight high-temperature applications.
热障涂层对于提高材料在高温环境下的耐热性至关重要。提出了一种制备碳纤维增强塑料(CFRP)复合材料双层渐变孔隙度TBC的新方法。TBC采用火焰喷涂工艺制备,由致密层和多孔层组成:(1)将氧化钇稳定的氧化锆(YSZ)颗粒直接喷涂到整齐的碳织物基底上,形成致密层;(2)将YSZ颗粒与牺牲聚醚醚酮(PEEK)颗粒共喷涂,形成多孔层。通过改变PEEK注入距离(D)和PEEK进料速率(R)来控制多孔层的孔隙度。研究了TBC层孔隙度与导热系数之间的相关性,以评估其热障性能。采用D = 5 cm, R = 1.0 g/min制备TBC,采用CFRP部分固化和真空成型制备双层/CFRP复合材料。厚度为660 μm,孔隙率为34%,导热系数为0.27 W/m∙K的TBC层在500℃时对CFRP基板的保护作用显著,使CFRP在230℃以上的表面温度降低。热冲击试验后的热力学分析表明,双层TBC/CFRP复合材料分别保留了其原始抗弯强度和模量的87%和75%,而纯CFRP复合材料完全烧毁。本研究探索了应用火焰喷射技术开发具有可调孔隙度的高效双层tbc,以最大限度地提高其热障性能。目前研究的所有结果都为CFRP复合材料的设计和开发提供了新的见解,进而为纤维复合材料的tbc提供了新的见解,这将有利于广泛的轻质高温应用。
Hybrid-structured carbon fiber fabric/silk fiber non-woven fabric/carbonyl iron powder/epoxy composites with highly efficient electromagnetic interference shielding and mechanical properties
Lieran Huang, Yuxin He, Ziang Gao, Houyi Du, Ruilin Zhang, Li Zhang, Hu Liu, Chuntai Liu, Changyu Shen
doi:10.1016/j.compscitech.2024.110868
具有高效电磁干扰屏蔽和机械性能的混合结构碳纤维织物/丝纤维无纺布/羰基铁粉/环氧复合材料
In this study, carbonyl iron powder (CIP) was loaded onto the surfaces of carbon fiber fabric (CF) and silk non-woven fabric (SF) through a spraying process and surface micro-dissolve & adhesion (SMDA) process, respectively. Subsequently, CF/SF/CIP reinforced epoxy (CF/SF/CIP/EP) composites with different hybrid structures were fabricated using vacuum-assisted resin transfer molding (VARTM) technique. The effects of these hybrid structures on both the electromagnetic interference (EMI) shielding performance and mechanical properties of the composites were systematically assessed. The results reveal that with an increase in the layer fraction of CF, the mechanical properties of the modified hybrid fibers (HFs) composites demonstrate a positive hybrid effect. Particularly noteworthy is the observation that when the layer ratio of CF to SF is maintained at 1:1, the M-CSCS/EP composites featuring an interlayer hybrid structure exhibit the highest EMI shielding effectiveness of 34.9 dB within the X-band of 8.2-12.4 GHz. This enhancement is attributed to the improved interfacial polarization loss capability of incident electromagnetic waves, facilitated by the increased two-phase interface formed between CF and SF. Moreover, the composite exhibits excellent mechanical properties, including a tensile strength of 339.9 MPa, interlaminar shear strength of 32.1 MPa, and impact strength of 98.2 kJ/m2. Consequently, the HFs composites developed in this study offer a commendable balance between EMI shielding performance and mechanical properties, rendering them highly suitable for a wide array of applications in aerospace, rail transportation, and communication equipment.
本研究将羰基铁粉(CIP)分别通过喷涂工艺和表面微溶解与粘附(SMDA)工艺加载到碳纤维织物(CF)和真丝无纺布(SF)表面。随后,采用真空辅助树脂传递模塑(VARTM)技术制备了不同混杂结构的CF/SF/CIP增强环氧树脂(CF/SF/CIP/EP)复合材料。系统评价了这些杂化结构对复合材料电磁干扰屏蔽性能和力学性能的影响。结果表明,随着CF层数的增加,改性混杂纤维(HFs)复合材料的力学性能表现出积极的混杂效应。特别值得注意的是,当CF与SF的层比保持在1:1时,具有层间杂化结构的M-CSCS/EP复合材料在8.2-12.4 GHz的x波段内具有最高的34.9 dB的EMI屏蔽效能。这种增强是由于CF和SF之间形成的两相界面增加,提高了入射电磁波的界面极化损耗能力。复合材料具有优异的力学性能,抗拉强度为339.9 MPa,层间剪切强度为32.1 MPa,冲击强度为98.2 kJ/m2。因此,本研究中开发的高频复合材料在EMI屏蔽性能和机械性能之间提供了值得称赞的平衡,使其非常适合在航空航天,铁路运输和通信设备中的广泛应用。
Cold Crystallization Behavior of Poly(Lactic Acid) Induced by Poly(Ethylene Glycol)-Grafted Graphene Oxide: Crystallization Kinetics and Polymorphism
Yang Su, Si-Ru Li, Si-Yuan Zhou, Hao-Ran Yang, Ling Xu, Gan-Ji Zhong, Jia-Zhuang Xu, Zhong-Ming Li, Xiao-Ming Tao, Yiu-Wing Mai
doi:10.1016/j.compscitech.2024.110871
聚乙二醇接枝氧化石墨烯诱导聚乳酸冷结晶行为:结晶动力学和多态性
Cold crystallization between the glass transition and melt temperature is of particular significance for crystalline regulation due to the slow crystallization rate of poly(lactic acid) (PLA). Incorporation of nucleation agents can promote PLA crystallization by reducing the nucleation activation energy and offering nucleation sites. Herein, we investigated the cold crystallization behavior of PLA induced by poly(ethylene glycol)-grafted graphene oxide (PEGgGO) which was synthesized and identified as a powerful nucleation agent for melt crystallization. The obtained results showed that PEGgGO not only accelerated the cold crystallization kinetics of PLA, but also promoted the polymorphic transition kinetics during the heating process. The half crystallization time of PLA induced by PEGgGO was shortened by 51% and the final crystallinity increased by 57% compared to that induced by GO alone at the same loading of 0.5 wt.%. In addition, relative to GO, PEGgGO enabled the α′-to-α phase transition kinetics of PLA by a reduced transition temperature range of 26% due to its excellent nucleation ability even at cold crystallization. The flexible PEG chains on GO facilitated crystalline regulation of PLA owing to the improved chain mobility. This work provides a broader framework for fashioning semicrystalline PLA products with enhanced crystallinity and refined crystal structure towards prospective applications.
由于聚乳酸(PLA)的结晶速度慢,玻璃化转变和熔体温度之间的冷结晶对结晶调节具有特殊的意义。成核剂的加入通过降低成核活化能和提供成核位点来促进聚乳酸的结晶。本文研究了聚乙二醇接枝氧化石墨烯(PEGgGO)诱导聚乳酸的冷结晶行为。聚乙二醇接枝氧化石墨烯(PEGgGO)是一种强大的熔融结晶成核剂。结果表明,PEGgGO不仅加速了聚乳酸的冷结晶动力学,而且在加热过程中促进了聚乳酸的多晶转变动力学。在相同负载0.5% wt.%的情况下,PEGgGO诱导聚乳酸的半结晶时间比单独使用GO诱导聚乳酸的半结晶时间缩短51%,最终结晶度提高57%。此外,由于PEGgGO具有优异的成核能力,即使在冷结晶时,PEGgGO也能使PLA的α′-α相变动力学降低26%。氧化石墨烯上的柔性聚乙二醇链由于提高了链的迁移率而促进了聚乳酸的结晶调节。这项工作为塑造具有增强结晶度和精细晶体结构的半结晶PLA产品提供了更广泛的框架,以实现潜在的应用。
Interface reinforced by polymer binder for expandable carbon fiber structural lithium-ion battery composites
Jianxun Li, Xu Liu, Zihan Hu, Yuehua Liu, Hongfei Li, Limin Zhou
doi:10.1016/j.compscitech.2024.110873
聚合物粘结剂增强可膨胀碳纤维结构锂离子电池复合材料界面
Carbon fiber (CF) composite structural battery (SB) is a novel energy storage device that integrates electrochemical energy storage with mechanical load-bearing capability. Carbon fiber's inherent conjugated carbon network possesses excellent electronic conductivity, thus serving as a current collector for electrode active materials. The bonding between active materials and carbon fibers relies on their manufacturing processes, requiring optimization of their electrochemical performance and addressing the challenges of large-scale production. In this work, a LiFePO4/PEO-LiTFSI/CF composite cathode was fabricated using the direct coating method. Polyethylene oxide (PEO) acted as a binder to form a stable LiFePO4 (LFP) coating on the carbon fiber woven fabric, while multi-walled carbon nanotube (MWCNT) were employed to construct a conductive network. This significantly enhanced both the charge-discharge performance and interface stability of the composite cathode. This composite cathode achieved a first-cycle discharge-specific capacity of 133.21 mAh·g-1 at 0.1 C rate and retained 93.7% of its capacity after 200 cycles at 1 C rate. Based on this composite cathode, multiple active material coatings were integrated onto a carbon fiber woven fabric to manufacture an expandable multi-cell structural battery. Its advantage lies in the ability of multiple battery cells to disperse stress under load, thus achieving a higher capacity retention rate under bending loads. The structural battery possesses a high degree of customizability, allowing for adjustment of the area, position, and quantity of active material coatings to meet the demands of practical conditions.
碳纤维复合结构电池(SB)是一种集电化学储能与机械承载能力于一体的新型储能装置。碳纤维固有的共轭碳网络具有优异的电子导电性,可作为电极活性材料的集电流体。活性材料与碳纤维之间的粘合依赖于其制造工艺,需要优化其电化学性能并解决大规模生产的挑战。本文采用直接包覆法制备了LiFePO4/PEO-LiTFSI/CF复合阴极。聚乙烯氧化物(PEO)作为粘结剂在碳纤维织物上形成稳定的LiFePO4 (LFP)涂层,而多壁碳纳米管(MWCNT)则用于构建导电网络。这大大提高了复合阴极的充放电性能和界面稳定性。该复合阴极在0.1 C倍率下的第一次放电比容量为133.21 mAh·g-1,在1 C倍率下循环200次后仍保持93.7%的容量。基于这种复合阴极,将多种活性材料涂层集成到碳纤维编织织物上,制造出可膨胀的多电池结构电池。它的优点在于多个电池单元在负载下能够分散应力,从而在弯曲载荷下实现更高的容量保持率。结构电池具有高度的可定制性,允许调整活性物质涂层的面积、位置和数量,以满足实际条件的需求。