今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 4 篇
Adjustable mechanical performances of 4D-printed shape memory lattice structures
Yu Dong, Kaijuan Chen, Hu Liu, Jian Li, Zhihong Liang, Qianhua Kan
doi:10.1016/j.compstruct.2024.117971
4D 打印形状记忆晶格结构的可调机械性能
Lattice structures are widely used due to their inherent advantages. With the development of smart devices, there is a growing demand for programmable, adjustable, and reconfigurable performances. However, a significant limitation of traditional lattice structures is that their shape, function, and performance cannot be changed after fabrication. In order to address this issue, we conducted experimental and simulated investigations on the shape memory effect, adjustable mechanical performances, and their deformation mechanism using the shape memory programming method. Two bending-dominated lattice structures, namely four curved bars lattice structure (FCBL) and sinusoidal wave horseshoe lattice structure (SWHL), were taken as examples. Results show that the deformation modes of both structures are switched from a bending-dominated mode to a stretching-dominated one after programming while exhibiting distinct bending sections. FCBL displays a 'C' shape with one bending section, whereas SWHL exhibits an 'S' shape with two bending sections. These deformation modes significantly enhance the tensile moduli by 480.9% (FCBL) and 1546% (SWHL), and change their Poisson’s ratio from -0.29 to 0.25 (FCBL) and -0.31 to 0.43 (SWHL), respectively. The modulus and Poisson’s ratio of FCBL and SWHL are well reproduced by the finite element modeling, providing a reference for designing the tunable mechanical performances of lattice structures.
晶格结构因其固有的优势而得到广泛应用。随着智能设备的发展,人们对可编程、可调节和可重构性能的需求日益增长。然而,传统晶格结构的一个显著局限是其形状、功能和性能在制造后无法改变。为了解决这个问题,我们利用形状记忆编程方法对形状记忆效应、可调机械性能及其变形机制进行了实验和模拟研究。我们以两种以弯曲为主的晶格结构(即四弯杆晶格结构(FCBL)和正弦波马蹄形晶格结构(SWHL))为例进行了研究。结果表明,这两种结构的变形模式在编程后都从以弯曲为主的模式转换为以拉伸为主的模式,同时表现出明显的弯曲截面。FCBL 显示出具有一个弯曲截面的 "C "形,而 SWHL 则显示出具有两个弯曲截面的 "S "形。这些变形模式分别将拉伸模量大幅提高了 480.9%(FCBL)和 1546%(SWHL),并将泊松比从 -0.29 变为 0.25(FCBL)和 -0.31 变为 0.43(SWHL)。有限元建模很好地再现了 FCBL 和 SWHL 的模量和泊松比,为设计晶格结构的可调力学性能提供了参考。
Carbon fibre surface modification by plasma for enhanced polymeric composite performance: A review
Maximilian Pitto, Holger Fiedler, Nam Kyeun Kim, Casparus Johannes Reinhard Verbeek, Tom David Allen, Simon Bickerton
doi:10.1016/j.compositesa.2024.108087
利用等离子体对碳纤维表面进行改性,以提高聚合物复合材料的性能:综述
Energetic species in plasma have been used for four decades to functionalise or coat the hydrophobic and inert carbon fibre (CF) surface with the aim to enhance interface performance with polymeric matrices. To encourage a data-driven polymeric composite manufacturing process, this review communicates introductory plasma science, treatment methods, reaction mechanisms, fibre properties and composite performance. The digest on fibre properties after plasma modification informs the mechanical property enhancement of micro- and macro-scale fibre-reinforced polymeric composites. To reliably emulate CF plasma treatments for industrial polymeric composites manufacture, the bulk plasma must be characterised to produce the same reactive species in a non-identical plasma device. Integration of plasma diagnostics can spearhead interdisciplinary work to predict CF surface modification throughout the bundle and fabric, substituting the trial and error status quo. To justify the use of plasma, its environmental, social, and economic impact must be quantitatively compared to alternative fibre surface treatments.
四十年来,等离子体中的高能物质一直被用来对疏水性和惰性碳纤维(CF)表面进行功能化或涂层处理,以提高其与聚合物基质的界面性能。为了鼓励以数据为导向的聚合物复合材料制造工艺,本综述介绍了等离子体科学、处理方法、反应机制、纤维特性和复合材料性能。等离子体改性后的纤维性能摘要为微观和宏观尺度纤维增强聚合物复合材料机械性能的提高提供了信息。要在工业聚合物复合材料制造中可靠地模拟 CF 等离子处理,必须对大块等离子体进行表征,以便在非相同的等离子体设备中产生相同的反应物种。整合等离子体诊断技术可以引领跨学科工作,预测整个纤维束和纤维织物的 CF 表面改性,从而取代反复试验的现状。为了证明使用等离子体的合理性,必须将其对环境、社会和经济的影响与其他纤维表面处理方法进行量化比较。
A lightweight, flexible, and polarization-insensitive microwave absorbing honeycomb core using conductive losses in printed periodic pattern
Sang Min, Won Jun Lee
doi:10.1016/j.compositesa.2024.108089
一种轻质、灵活、对偏振不敏感的微波吸收蜂窝芯,采用印刷周期图案中的导电损耗
This study proposes a method for providing electromagnetic function by arranging patterns three-dimensionally on honeycomb partition walls. A conductive paste is thinly printed to fabricate a resistance component. To increase the current path induced by the incident electromagnetic waves, a rectangular pattern with an aspect ratio is used to further generate electromagnetic losses. Rectangular patterns are arranged alternately to ensure the homogeneity of the entire honeycomb medium. The proposed honeycomb achieved excellent absorption performance in the C, X, and Ku bands, regardless of the polarization. Simulations were used to show that the microwave-absorption performance of a honeycomb with a three-dimensional pattern could be estimated analytically. The obtained results were compared with those of other studies. The proposed honeycomb was effective in reducing the broadband monostatic radar cross section when applied to the leading edge of a wing box.
本研究提出了一种通过在蜂窝隔墙上三维排列图案来提供电磁功能的方法。通过薄薄地印刷导电浆料来制造电阻元件。为了增加入射电磁波引起的电流路径,使用了具有高宽比的矩形图案,以进一步产生电磁损耗。矩形图案交替排列,以确保整个蜂窝介质的均匀性。所提出的蜂窝在 C、X 和 Ku 波段都实现了出色的吸收性能,与偏振无关。模拟结果表明,具有三维图案的蜂窝的微波吸收性能可以通过分析估算出来。所得结果与其他研究结果进行了比较。当应用于翼盒前缘时,所提出的蜂窝能有效减少宽带单静态雷达截面。
Calcium crosslinked macroporous bacterial cellulose scaffolds with enhanced in situ mineralization and osteoinductivity for cranial bone regeneration
Xiaowei Xun, Yaqiang Li, Ming Ni, Yong Xu, Jiaxin Li, Dongxue Zhang, Guochang Chen, Haiyong Ao, Honglin Luo, Yizao Wan, Tao Yu
doi:10.1016/j.compositesb.2024.111277
用于颅骨再生的钙交联大孔细菌纤维素支架具有更强的原位矿化和骨诱导能力
The inherent biological inertness and lack of three-dimensional (3D) macroporous structures greatly hinder the use of pristine bacterial cellulose (BC) as a tissue engineering scaffold for bone regeneration. To address this issue, we developed a simple and effective strategy to fabricate a BC-based scaffold with excellent bioactivity and macroporous structure by crosslinking short-cut BC nanofibers using Ca2+. The Ca2+ crosslinked macroporous BC scaffold (MPBC@Ca) presents better structural stability due to the enhanced cellulose hydration. Importantly, the Ca2+ on the surface of BC nanofibers can serve as an active nucleation site to accelerate the deposition of hydroxyapatite (HAp), which is beneficial for the construction of biomimetic bone tissue extracellular matrix (ECM) microenvironment. The HAp-deposited MPBC@Ca scaffolds (HAp-MPBC@Ca) with biomimetic ECM microenvironment have excellent cytocompatibility and enhanced osteogenic differentiation of stem cells in vitro. Furthermore, the results of in vivo tests revealed that the biomimetic ECM microenvironment HAp-MPBC@Ca scaffold has favorable osteoinductivity and accelerates cranial bone tissue regeneration. This study proposes a novel strategy to improve the bioactivity of BC and presents the great potential of biomimetic ECM microenvironment BC-based scaffold for repairing large cranial bone defects.
原始细菌纤维素(BC)固有的生物惰性和缺乏三维(3D)大孔结构极大地阻碍了其作为组织工程支架用于骨再生。为解决这一问题,我们开发了一种简单有效的策略,通过使用 Ca2+ 交联短切 BC 纳米纤维,制造出一种具有优异生物活性和大孔结构的 BC 基支架。由于纤维素水合作用增强,Ca2+交联的大孔BC支架(MPBC@Ca)具有更好的结构稳定性。重要的是,BC 纳米纤维表面的 Ca2+ 可作为活性成核位点,加速羟基磷灰石(HAp)的沉积,有利于构建仿生骨组织细胞外基质(ECM)微环境。具有仿生 ECM 微环境的 HAp 沉积 MPBC@Ca 支架(HAp-MPBC@Ca)具有良好的细胞相容性,并能增强体外干细胞的成骨分化。此外,体内试验结果表明,仿生 ECM 微环境 HAp-MPBC@Ca 支架具有良好的骨诱导性,可加速颅骨组织再生。该研究提出了一种提高 BC 生物活性的新策略,并展示了基于生物仿生 ECM 微环境 BC 支架修复大面积颅骨缺损的巨大潜力。
Mathematical study of the mechanical properties of NOL rings with different winding process parameters
Zesheng Huang, Wei Shen, Lifeng Chen, Lvtao Zhu
doi:10.1016/j.compscitech.2024.110502
不同缠绕工艺参数下 NOL 环机械性能的数学研究
This study investigates the impact of different winding tension parameters (40 N, 45 N, and 50 N) on the quality of fiber-wrapped products using the Navy Ordnance Laboratory (NOL) composite rings. Design Expert software was utilized to analyze the response surface of fiber winding process parameters, including winding tension, winding speed, and curing temperature, which significantly influence the mechanical properties of the fiber. Mathematical models were developed to understand the combined effects of these process parameters on the mechanical properties of NOL rings. Furthermore, a satisfaction function was employed to synthesize the two mechanical response variables into a comprehensive index for parameter optimization. Experimental validation was conducted to verify the reliability of the proposed design scheme.
本研究使用海军军械实验室(NOL)的复合环,研究了不同缠绕张力参数(40 N、45 N 和 50 N)对纤维缠绕产品质量的影响。利用 Design Expert 软件分析了纤维缠绕工艺参数的响应面,包括缠绕张力、缠绕速度和固化温度,这些参数对纤维的机械性能有显著影响。通过建立数学模型,了解了这些工艺参数对 NOL 环机械性能的综合影响。此外,还采用了满意度函数,将两个机械响应变量综合成一个综合指标,用于参数优化。通过实验验证了所提设计方案的可靠性。
Waste cotton stalks enhancing the impact and crystallization performances of polylactic acid/polypropylene composite with PP-g-mah compatibilizer
Jin Shang, Abdukaiyum Abdurexit, Ruxangul Jamal, Tursun Abdiryim, Xiong Liu, Fangfei Liu, Zhiwei Li, Yanqiang Zhou, Jin Wei, Xinsheng Tang
doi:10.1016/j.compscitech.2024.110485
废棉秆与 PP-g-mah 相容剂可提高聚乳酸/聚丙烯复合材料的抗冲击和结晶性能
Although polymers based on polylactic acid (PLA) are considered by researchers as prime candidates for replacing traditional plastics, they are confronted with challenges including high production costs, limited thermal stability, and inferior impact resistance. In this study, novel composites with exceptional impact resistance, robust thermal stability, and satisfactory crystalline properties were fabricated by using PLA and polypropylene (PP) as raw materials, PP-g-MAH was employed as a compatibilizer to enhance the compatibility between the individual components. by adjusting the quantity of discarded cotton stalk fibers (CSF). The optimal mass ratio of CSF was determined to be 20%, resulting in a composite that exhibited a moderate increase of 56.31% in impact strength and a remarkable improvement of 23.05% in Vicat softening temperature. While the crystallinity was enhanced and the crystallization temperature (Tc) value decreased, the storage modulus also increased. Furthermore, the observed increase in storage modulus within the temperature range of 80 °C–100 °C was attributed to the influence of polymer cold crystallization. The hydrophobicity of the composite was enhanced. Significantly, this strategy can be extended to the application of other plant fibers, improving the crystalline properties of semi-crystalline polymers such as PLA and exemplifying the true ‘valorization of waste' through the secondary utilization of discarded CSF.
尽管以聚乳酸(PLA)为基础的聚合物被研究人员视为替代传统塑料的主要候选材料,但它们也面临着生产成本高、热稳定性有限和抗冲击性差等挑战。本研究以聚乳酸(PLA)和聚丙烯(PP)为原料,采用 PP-g-MAH 作为相容剂,通过调整废弃棉秆纤维(CSF)的用量,制备出具有优异抗冲击性、强大热稳定性和令人满意的结晶特性的新型复合材料。最终确定 CSF 的最佳质量比为 20%,使复合材料的冲击强度提高了 56.31%,维卡软化温度显著提高了 23.05%。在提高结晶度和降低结晶温度 (Tc) 值的同时,还提高了储存模量。此外,在 80 °C-100 °C 的温度范围内观察到的储存模量增加是由于聚合物冷结晶的影响。复合材料的疏水性得到了增强。值得注意的是,这一策略可扩展到其他植物纤维的应用,改善半结晶聚合物(如聚乳酸)的结晶特性,并通过对废弃 CSF 的二次利用体现真正的 "废物利用"。
Flexible bandwidth-enhanced metamaterial absorbers with epoxy/graphene nanoplatelets-silver nanowire polymer composites as substrates
M. Anjali, Raghunath Sahoo, Lincy Stephen, C.V. Krishnamurthy, V. Subramanian
doi:10.1016/j.compscitech.2024.110492
以环氧树脂/石墨烯纳米片-银纳米线聚合物复合材料为基材的柔性带宽增强超材料吸收器
The realm of flexible devices has seen considerable advancement in recent technology due to their ability to bend and conform to particular shapes. Flexible metamaterial absorbers offer the advantage of combining the features of conventional metamaterials with the attributes of conformal systems, thereby opening new avenues in electromagnetic technology. This work involves the realization of flexible metamaterial absorbers with epoxy/graphene nanoplatelets-silver nanowire (GnP-AgNW) polymer composites as substrates; with a bandwidth enhancement achieved by incorporating losses in the substrate and combining resonances in the unit cell. A novel in-situ technique is employed to synthesize the nanohybrid GnP-AgNW (GA) with different weight percentages of AgNWs grown on GnP (GAx; x = 10, 15, 20 wt%). The dielectric measurements of the polymers showed that an increase in weight percentages of AgNWs in the composite enhanced the dielectric constant as well as losses of the polymer (εr՛: 7.7 to 8.8 and εr՛՛: 0.62 to 1.12). The numerical study on the designed flexible metamaterial absorbers with these substrates of thickness 1.4 mm showed a maximum absorptivity of 99% with a bandwidth (having absorption >90%) varying between 1.2 and 1.86 GHz. The experimental measurements on the fabricated metamaterial absorber were found to match the simulation results closely. The polymer composites demonstrated in this work are attractive candidates as substrates for metamaterial absorbers for conformal applications. This paper approaches the problem of bandwidth enhancement of metamaterial absorbers by material engineering along with the resonant structure optimization leading to a synergetic effect in the properties of absorber.
柔性器件能够弯曲并符合特定形状,因此在最近的技术领域取得了长足的进步。柔性超材料吸波材料具有将传统超材料的特性与保形系统的属性相结合的优势,从而为电磁技术开辟了新的道路。这项研究以环氧树脂/石墨烯纳米片-银纳米线(GnP-AgNW)聚合物复合材料为基材,实现了柔性超材料吸波材料;通过在基材中加入损耗和在单元格中结合共振实现了带宽增强。我们采用了一种新颖的原位技术来合成纳米杂化 GnP-AgNW(GA),在 GnP 上生长不同重量百分比的 AgNW(GAx;x = 10、15、20 wt%)。聚合物的介电测量结果表明,复合材料中 AgNWs 重量百分比的增加提高了聚合物的介电常数和损耗(εr՛:7.7 至 8.8;εr՛՛:0.62 至 1.12)。对使用这些厚度为 1.4 毫米的基底设计的柔性超材料吸波材料进行的数值研究表明,其最大吸收率为 99%,带宽(吸收率大于 90%)在 1.2 至 1.86 千兆赫之间。对制作的超材料吸收器的实验测量结果与模拟结果非常吻合。这项工作中展示的聚合物复合材料是具有吸引力的超材料吸收器基材,可用于保形应用。本文通过材料工程和谐振结构优化来解决超材料吸收器的带宽增强问题,从而在吸收器的性能方面产生协同效应。
Trans-scale analysis of 3D braided composites with voids based on micro-CT imaging and unsupervised machine learning
Xinyi Song, Jin Zhou, Di Zhang, Shenghao Zhang, Pei Li, Longteng Bai, Xiaohui Yang, Feiping Du, Xuefeng Chen, Zhongwei Guan, Wesley J. Cantwell
doi:10.1016/j.compscitech.2024.110494
基于显微 CT 成像和无监督机器学习的空隙三维编织复合材料跨尺度分析
Voids are unavoidable during the manufacturing of 3D braided composites. This study proposes an unsupervised machine learning method combined with micro-computed tomography (micro-CT) scanning and a progressive damage analysis to analyze defects in these composites at a trans-scale level. The method enables the creation of real multiscale models and the determination of the porosity in both the intra-yarn (1.52 %) and inter-yarn (5.04 %) planes. Here, the unsupervised machine learning method is introduced in a trans-scale damage analysis to reduce calculation dimensions and to visualize the clustering data. A user-defined material subroutine (UMAT) is also developed to implement the trans-scale damage model. The experimental validation of the simulation results demonstrates the effective trans-scale damage analysis, showing the predominant pull-shear damage in the yarns, which is primarily located at the interfaces both between the yarns and between the yarns and the matrix. Finally, based on the scanned geometric data the degradation in modulus and strength of 3D braided composites with porosity is studied.
在三维编织复合材料的制造过程中,空洞是不可避免的。本研究提出了一种无监督机器学习方法,结合微型计算机断层扫描(micro-CT)和渐进式损伤分析,在跨尺度水平上分析这些复合材料中的缺陷。该方法可创建真实的多尺度模型,并确定纱内(1.52%)和纱间(5.04%)平面的孔隙率。在此,我们在跨尺度损伤分析中引入了无监督机器学习方法,以减少计算维数并实现聚类数据的可视化。此外,还开发了用户自定义材料子程序(UMAT)来实现跨尺度损伤模型。模拟结果的实验验证证明了跨尺度损伤分析的有效性,显示了纱线中主要的拉剪损伤,这种损伤主要位于纱线之间以及纱线与基体之间的界面。最后,根据扫描的几何数据,研究了带有孔隙率的三维编织复合材料的模量和强度退化情况。