今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇
Investigating the mode one interlaminar performance of semi-woven 3D printed hybrid composites
Cheng Huang, Michael Norton, Mathew W. Joosten
doi:10.1016/j.compstruct.2024.118802
研究半编织3D打印杂化复合材料的模一层间性能
Interlaminar performance governs a composites’ ability to resist delamination and cracking between layers. It’s hypothesized that the interlaminar fracture toughness of hybrid composites exhibit a linear relationship with the fibre composition content. To validate the hypothesis, the interlaminar performance of 3D printed intraply hybrid semi-woven composites was investigated using double cantilever beam (DCB) samples in the present study. The hybrid composites were fabricated from two types of tow-preg filaments that consist of either carbon or glass fibres impregnated with polyamide, referred to as low elongation (LE) and high elongation (HE) materials respectively. The experimental results of propagation interlaminar fracture toughness of semi-woven hybrid composites aligns well with the linear rule of mixtures (ROM) predictions. Scanning electron microscopy (SEM) provided microstructural insights into fracture mechanisms, exhibiting different fracture surface features that varied with the ratio of low elongation (LE) material. These findings show that the linear ROM can predict the interlaminar performance of semi-woven intraply hybrid composites based on the material properties of the constituent material properties, offering a straightforward method for optimising fracture toughness by adjusting the ratio of fibres within the composite structure.
层间性能决定了复合材料抵抗层间分层和开裂的能力。假设混杂复合材料的层间断裂韧性与纤维组分含量呈线性关系。为了验证这一假设,本研究采用双悬臂梁(DCB)样品对3D打印层间混杂半编织复合材料的层间性能进行了研究。杂化复合材料由两种类型的低延伸(LE)和高延伸(HE)材料制成,分别由碳或玻璃纤维浸渍聚酰胺组成。半编织混杂复合材料层间断裂韧度的实验结果与线性混合规律(ROM)的预测结果吻合较好。扫描电子显微镜(SEM)提供了断裂机制的微观结构洞察,显示出不同的断口表面特征随低延伸率(LE)材料比例的变化而变化。这些发现表明,线性ROM可以根据组成材料的材料性能预测半编织层间混杂复合材料的层间性能,为通过调整复合材料结构中纤维的比例来优化断裂韧性提供了一种直接的方法。
Enhancing honeycomb surface quality by harnessing vortex effect in electrochemical grinding
Zhenghui Ge, Maolong Chen, Rui Wang, Bing Zhang, Yongwei Zhu
doi:10.1016/j.compositesa.2024.108641
利用电化学磨削中的涡流效应提高蜂窝表面质量
Superalloy honeycomb structures have been widely used in aerospace components due to its excellent mechanical and physical performances. Electrochemical grinding offers great potential in reducing honeycomb core defects. However, the porous characteristics pose new machining challenges like excessive corrosion. Herein, the vortex effect generated by the honeycomb pores was investigated to restrain excessive corrosion, thereby effectively improving the honeycomb surface quality. Simulation results indicate that the flow field on honeycomb surfaces significantly differ from solid surfaces, with the electrolyte injection angle playing a crucial role in influencing the vortex effect. The electrolyte injection angle of 50° has been optimized to enhance the vortex effect, which promote the residue accumulation and reduce excessive corrosion. Experimental results demonstrate that the maximum excessive corrosion depth can be significantly reduced from around 70 μm to less than 20 μm. This research provides valuable insights into leveraging the vortex effect for advanced honeycomb components.
高温合金蜂窝结构由于其优异的力学性能和物理性能,在航空航天部件中得到了广泛的应用。电化学磨削在减少蜂窝芯缺陷方面具有很大的潜力。然而,多孔特性带来了新的加工挑战,如过度腐蚀。本文研究了蜂窝孔产生的涡流效应来抑制过度腐蚀,从而有效改善蜂窝表面质量。仿真结果表明,蜂窝表面的流场与固体表面的流场存在显著差异,其中电解质注入角度对旋涡效应的影响至关重要。优化了50°的电解液注入角,增强了涡流效应,促进了残渣的积累,减少了过度腐蚀。实验结果表明,最大过腐蚀深度可以从70 μm左右显著降低到20 μm以下。这项研究为利用先进蜂窝部件的涡流效应提供了有价值的见解。
Investigation of hole quality Enhancement in new glass/flax laminates via hybrid drilling techniques
Hao Ye, Jiong Zhang, Yunshu Shang, Guiyin Xu, Jiaming Zhan, Steven Marguet, Habiba Bougherara, Redouane Zitoune, Hao Wang
doi:10.1016/j.compositesa.2024.108651
复合钻孔技术提高新型玻璃/亚麻层压板孔质量的研究
Flax/epoxy composites are commonly used natural fibre-reinforced materials with potential applications in aviation, automotive, and marine industries. To enhance the mechanical and hygrothermal properties of flax/epoxy laminates, glass/epoxy layers are incorporated, creating a novel glass/flax composite. However, drilling this composite encounters some problems, particularly due to poor hole quality and insufficient understanding of the associated damage mechanisms. Hence, this study systematically addresses these problems via various drilling conditions, including dry drilling, drilling with backup support, cryogenic drilling, and hybrid drilling methods. The drilling force and machining quality such as delamination, surface roughness and topography of the hole were studied. Moreover, multi-scale damage characterization was performed using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM). Delamination was classified into two types according to its shape and distribution. Analysis of the defects reconstructed by the micro-CT method revealed that the hybrid drilling reduces the delamination volumes of the entry and the exit by 64.8% and 78.9%, respectively, compared to those in dry drilling.
亚麻/环氧复合材料是一种常用的天然纤维增强材料,在航空、汽车和海洋工业中具有潜在的应用前景。为了增强亚麻/环氧层压板的机械和湿热性能,加入了玻璃/环氧层,创造了一种新型的玻璃/亚麻复合材料。然而,钻井这种复合材料会遇到一些问题,特别是由于井眼质量差和对相关损伤机制的了解不足。因此,本研究通过各种钻井条件系统地解决了这些问题,包括干钻、后备支撑钻井、低温钻井和混合钻井方法。研究了钻孔力和加工质量,如孔的分层、表面粗糙度和形貌。此外,使用微计算机断层扫描(micro-CT)和扫描电子显微镜(SEM)进行了多尺度损伤表征。分层根据其形态和分布可分为两种类型。通过显微ct重建缺陷分析发现,与干钻相比,混合钻可使入口和出口的分层体积分别减少64.8%和78.9%。
Robust flexural performance of modified bamboo through strategic delignification and carboxymethyl cellulose modification
Yuchen Ben, Hongyun Luo, Wen Liu, Ziyu Ba, Jie Cui, Zhaoliang Guo, Renshan Sun
doi:10.1016/j.compositesa.2024.108655
通过战略性脱木质素和羧甲基纤维素改性改性竹子的强健弯曲性能
Developing sustainable structural materials from biological sources is highly essential. In this study, a simple three-step method, involving “alkali treatment − carboxymethyl cellulose (CMC) modification − convection drying” was introduced to fabricate high-performance bamboo materials. By strategically controlling the alkali treatment time at room temperature, an optimized lignin content was obtained. Meanwhile, further incorporation of green binding agent CMC facilitates the formation of hydrogen bonds, thereby improved the interfacial bonding strength. The modified bamboo exhibits robust flexural properties, with a flexural strength reaching three times that of natural bamboo, measuring at 418 MPa. By employing acoustic emission technology and fracture micromorphology analysis, the influence of hydrogen bonds in enhancing load transmission at the interface was revealed. This work proposes a green modification strategy for bamboo materials to enhance mechanical performance, broadening the application of bamboo in the field of green manufacturing ranging from construction to transportation.
从生物来源开发可持续的结构材料是非常必要的。采用碱处理-羧甲基纤维素(CMC)改性-对流干燥三步法制备高性能竹材料。通过对常温下碱处理时间的控制,获得了最佳的木质素含量。同时,绿色结合剂CMC的进一步掺入有利于氢键的形成,从而提高了界面的结合强度。改性竹具有强健的抗弯性能,抗弯强度达到天然竹的3倍,测量值为418 MPa。通过声发射技术和裂纹微观形貌分析,揭示了氢键在界面处增强载荷传递的影响。本文提出了一种提高竹材料力学性能的绿色改性策略,拓宽了竹在绿色制造领域的应用范围,从建筑到交通运输。
Microstructure and damage evolution in short carbon fibre 3D-printed composites during tensile straining
José Humberto S. Almeida, Arttu Miettinen, Fabien Léonard, Brian G. Falzon, Philip J. Withers
doi:10.1016/j.compositesb.2024.112073
短碳纤维3d打印复合材料在拉伸应变过程中的微观结构与损伤演化
Short-fibre thermoplastic composites offer a balance between cost, processability, and performance, as well as providing a use for recycled fibres making them attractive in various industrial applications. However, the fibres tend to be misaligned due to their low aspect ratio, which can impact mechanical performance. This work examines the as-manufactured microstructure of a chopped carbon fibre-reinforced nylon composite made by material extrusion additive manufacturing in terms of fibre misalignment, void content, shape and distribution before going on to determine its effect on damage evolution under tensile straining by in-situ time-lapse synchrotron computed tomography (CT). To this end, CT scans have been acquired at various stages throughout straining. A high degree of fibre alignment is observed with ≈ 86% within 14 ∘ of the extrusion axis, giving a Krenchel orientation factor of 0.75. The time-lapse CT image sequence reveals that because the mean fibre length ( ≈ 98 μ m .) is below the critical fibre length fibre fracture does not take place during plastic straining. Instead, failure occurs during straining from pre-existing voids and newly nucleated ones mainly located at fibre ends, their growth and coalescence. The experimental elastic modulus and strength are compared against the Cox-Krenchel and Kelly-Tyson analytical models that take into account fibre misalignment and length, which demonstrates that the fibre orientation is sufficient and future improvements in properties could be achieved by reducing the initial void content ( ≈ 2.3%) and increasing the length and volume fraction of the reinforcing fibres.
短纤维热塑性复合材料在成本、可加工性和性能之间取得了平衡,并为回收纤维提供了一种用途,使其在各种工业应用中具有吸引力。然而,由于其低纵横比,纤维往往会错位,这可能会影响机械性能。本研究考察了材料挤压增材制造的短切碳纤维增强尼龙复合材料在纤维错位、空隙含量、形状和分布方面的制造微观结构,然后通过原位延时同步加速器计算机断层扫描(CT)确定其对拉伸应变下损伤演变的影响。为此,在整个拉伸过程的各个阶段都获得了CT扫描。在距挤压轴14°的范围内,可以观察到高度约86%的纤维取向,因此克伦切尔取向系数为0.75。延时CT图像序列显示,由于纤维的平均长度(≈98 μ m)小于临界长度,纤维在塑性应变过程中没有发生断裂。相反,破坏发生在主要位于纤维末端的先前存在的空洞和新成核的拉伸过程中,它们的生长和合并。将实验弹性模量和强度与考虑纤维错位和长度的Cox-Krenchel和Kelly-Tyson分析模型进行了比较,结果表明纤维取向是充分的,未来可以通过降低初始空隙含量(≈2.3%)和增加增强纤维的长度和体积分数来改善性能。
Preparation of Continuous Glass Fiber Reinforced PEEK Filaments and High-Temperature Performance for Additive Manufacturing
Hao Zhang, Yiwei Chen, Wenzhe Song, Jinghua Zheng, Congze Fan, Zhongde Shan, Yuejie Wen, Xize Wang
doi:10.1016/j.compositesb.2024.112078
连续玻璃纤维增强PEEK长丝的制备及其增材制造的高温性能
Aerospace composite components are moving towards structural-functional integration. Aircraft conformal radomes, for example, are required to meet stringent criteria for structural support and dielectric performance under aerothermal conditions. Additively manufactured continuous glass fiber-reinforced polyetheretherketone (CGF/PEEK) shows promising application prospects due to its high-temperature resistance, excellent dielectric properties, and high forming flexibility. In this study, a set of CGF/PEEK prepreg filament forming equipment was designed, and the influence of process parameters on the forming quality of CGF/PEEK prepreg filaments was analyzed. Subsequently, CGF/PEEK components were additively manufactured, and their mechanical and dielectric properties under high-temperature environments were investigated. The failure mechanism and performance evolution with increasing temperature were revealed. At 250 °C, the tensile strength of the samples decreases by 27.6%, and the flexural strength decreases by 69.7%. The obtained data and theoretical insights contribute to a foundational understanding of the application of CGF/PEEK additive manufacturing components, particularly in high-temperature service conditions prevalent in the aerospace field.
航空航天复合材料部件正朝着结构功能一体化的方向发展。例如,飞机的保形天线罩需要在空气热条件下满足严格的结构支撑和介电性能标准。增材制造的连续玻璃纤维增强聚醚醚酮(CGF/PEEK)具有耐高温、优异的介电性能和较高的成型柔韧性,具有广阔的应用前景。设计了一套CGF/PEEK预浸长丝成型设备,分析了工艺参数对CGF/PEEK预浸长丝成型质量的影响。随后,通过增材制造CGF/PEEK组件,并对其在高温环境下的力学性能和介电性能进行了研究。揭示了其破坏机理和性能随温度升高的演化规律。在250℃时,试样的抗拉强度下降了27.6%,抗折强度下降了69.7%。获得的数据和理论见解有助于对CGF/PEEK增材制造组件应用的基本理解,特别是在航空航天领域普遍存在的高温服务条件下。
Concurrent Enhanced Energy Density and Efficiency in a Novel Designed Asymmetric Four-Layer Structure Composite Film via Macro-Interface Regulation
Yongjing Zhang, Ying Lin, Yanlong Ma, Qibin Yuan, Haibo Yang
doi:10.1016/j.compscitech.2024.111013
基于宏观界面调控的新型非对称四层复合材料膜的能量密度和效率提高
With the development of renewable energy sources, dielectric capacitors play a pivotal role in energy conversion devices. However, the current commercial dielectric film materials, due to their low energy density, struggle to meet the requirements for device miniaturization and modularization. In recent years, significant improvements in the discharged energy density (Ue) of composite films have been achieved through the incorporation of various ceramic fillers and the design of topological layer structures. Nonetheless, the energy storage efficiency (η) of these composite films remains low due to inevitable energy loss at the ceramic-polymer micro-interface, limiting their large-scale commercial application. To address this issue, our work introduces a novel strategy: by designing an asymmetric multilayer structure, multiple macro-interfaces are introduced to replace some of the micro-interfaces within composite films, thereby reducing energy loss and enhancing η. Specifically, we propose an innovative asymmetric four-layer structure composite film, which achieves a stellar Ue value of 34.54 J cm-3 and an unprecedented η value of 95.82% at 660 MV m-1. This design adequately reduces the adverse impact of internal micro-interfaces on the energy storage characteristics of the composite films, achieving the optimal integrated energy storage performance so far.
随着可再生能源的发展,介电电容器在能量转换设备中扮演着关键角色。然而,由于现有商业化介电薄膜材料的能量密度较低,它们难以满足设备微型化和模块化的要求。近年来,通过采用各种陶瓷填料和设计拓扑层结构,复合薄膜的放电能量密度(Ue)得到了显著提高。然而,由于陶瓷-聚合物微界面不可避免的能量损失,这些复合薄膜的能量存储效率(η)仍然较低,限制了它们的大规模商业应用。为了解决这一问题,我们的工作提出了一种新的策略:通过设计非对称多层结构,在复合薄膜中引入多个宏观界面,以替代其中的一些微界面,从而减少能量损失并提高η。具体来说,我们提出了一种创新的非对称四层结构复合薄膜,在660 MV m-1下实现了34.54 J cm-3的卓越Ue值和前所未有的95.82%的η值。该设计有效地降低了复合膜内部微界面对能量存储特性的不利影响,实现了迄今为止最佳的集成能量存储性能。