今日更新:Composite Structures 3 篇,Composites Part B: Engineering 3 篇
Damage of composite thin-walled L profiles made in one production cycle
Jarosław Gawryluk, Andrzej Teter
doi:10.1016/j.compstruct.2024.118705
复合材料薄壁L型型材在一个生产周期内的损伤
The experimental results for a thin-walled laminated L-profile under uniform shortening are discussed in this paper. The objective of this study is to explore if accurately manufactured thin-walled structures exhibit similar behaviour at their limit state. Test samples consisted of 18 carbon laminate plies with a nominal structural thickness 0.81 mm. Geometry analysis of real samples was carried out on all samples using a 3D scanner. The columns are subjected to uniform shortening using a testing machine until they fail structurally. Additionally, acoustic emission and the Aramis system are employed. Despite being produced in a single manufacturing cycle, three different form of damage are identified: a crack in one wall near the sample’s center, opening of both walls, and crushing of one end. The acoustic emission signals acquired are analyzed to determine the load at which damage initiates, as well as the moments at which matrix and fiber breakage occur. The accuracy of the sample production (including its thickness and geometrical imperfections) has a significant impact on the form of damage that occurs when thin-walled profiles with one corner are compressed.
本文讨论了薄壁层压l型型材在均匀缩短作用下的实验结果。本研究的目的是探索是否精确制造薄壁结构在其极限状态下表现出类似的行为。测试样品由18层碳层压板层组成,公称结构厚度0.81 mm。使用三维扫描仪对所有样品进行真实样品的几何分析。柱受到均匀缩短使用试验机,直到他们的结构失效。此外,声发射和阿拉米斯系统的应用。尽管在一个制造周期内生产,但确定了三种不同形式的损坏:靠近样品中心的一面墙壁出现裂缝,两面墙壁裂开,一端破碎。对采集到的声发射信号进行分析,以确定损伤开始时的载荷,以及基体和纤维发生断裂的时刻。样品生产的准确性(包括其厚度和几何缺陷)对单角薄壁型材被压缩时发生的损伤形式有重大影响。
Optimal design of electrical conductivity of hybrid multi-dimensional carbon fillers reinforced porous cement-based Composites: Experiment and modelling
Yucheng Fan, Chuang Feng, Ziyan Hang, Luming Shen, Wengui Li
doi:10.1016/j.compstruct.2024.118714
复合多维碳填料增强多孔水泥基复合材料电导率优化设计:实验与建模
Cement-based composites with tailored electrical conductivity have promising applications in various intelligent and multifunctional infrastructures. Hybrid reinforcement using multi-dimensional carbon nanofillers is an effective approach for tailoring. However, determining the optimal recipe while balancing electrical properties and cost is challenging, which has not been carried out previously. This study develops a comprehensive micromechanical model with imperfect micromorphology, interface effect and electron tunneling to predict the electrical conductivity of cement-based composites reinforced with different combinations of 0D (zero-dimensional)-carbon black (CB), 1D-carbon nanotube (CNT) and 2D-graphene nanoplatelet (GNP). The influence of pore orientation on the electrical conductivity of the carbon nanofiller reinforced cement-based composites (CNRCCs) is studied for the first time and an effective conductive cross-sectional area method is proposed to investigate the anisotropy of the electrical conductivity in the CNRCCs. Furthermore, this model captures the synergistic effects of the hybrid carbon nanofillers, which has not been addressed in existing theoretical work on conductive composites. The developed model exhibits outstanding agreement with the experimental data of various samples. The optimal proportions for maximum electrical conductivity and performance-to-cost ratio are identified, such as mixing ratios of 80:20 for 0D-CB + 1D-CNT, 50:50 to 70:30 for 0D-CB + 2D-GNP, and 90:10 for 1D-CNT + 2D-GNP. The work is envisaged to provide guidelines for optimizing the performances of CNRCCs with tailored electrical properties and moderate cost.
具有定制导电性的水泥基复合材料在各种智能和多功能基础设施中有着广阔的应用前景。利用多维碳纳米填料进行复合加固是一种有效的裁剪方法。然而,在平衡电性能和成本的同时确定最佳配方是具有挑战性的,这在以前没有进行过。本研究建立了一个综合的微观力学模型,考虑了不完美的微观形貌、界面效应和电子隧道效应,以预测零维碳黑(CB)、一维碳纳米管(CNT)和二维石墨烯纳米板(GNP)不同组合增强的水泥基复合材料的导电性。首次研究了孔隙取向对碳纳米填料增强水泥基复合材料(CNRCCs)电导率的影响,并提出了一种有效导电截面积法来研究CNRCCs电导率的各向异性。此外,该模型捕获了混合碳纳米填料的协同效应,这在现有的导电复合材料理论工作中尚未得到解决。所建立的模型与各种样品的实验数据具有良好的一致性。确定了最大电导率和性能成本比的最佳比例,例如0D-CB + 1D-CNT的混合比例为80:20,0D-CB + 2D-GNP的混合比例为50:50至70:30,1D-CNT + 2D-GNP的混合比例为90:10。预计这项工作将为优化cnrcc的性能提供指导,使其具有量身定制的电气性能和适度的成本。
Repair technologies for structural polymeric composites: An automotive perspective
Sandeep Olhan, Bindu Antil, B.K. Behera
doi:10.1016/j.compstruct.2024.118711
结构聚合物复合材料的修复技术:汽车视角
Structural polymeric composite (SPC) materials have become increasingly popular in the automotive industry due to their lightweight potential, excellent fatigue, and impact resistance, superior damping behavior, and high strength and stiffness properties. The automotive sector shows a strong interest in enhancing the repair methods for SPC. However, with immature SPC design rules, production processes, and joining technologies, the safety and efficiency of composite automotive components will heavily rely on effective structural maintenance and repair. Despite its importance, minimal progress has been made in repairing SPC materials over the past decades. Consequently, there is a pressing need to enhance composite repair practices and foster innovation in this vital area. This paper aims to address this demand by focusing on repair techniques and covering various state-of-the-art processing steps associated with SPC materials in the automotive industry. The review contributes an overview of several crucial aspects of composite repair, encompassing advanced non-destructive testing (NDT) methods for damage assessment, machining of structural composites, and surface preparation techniques. Furthermore, it delves into scarfing repair methods, such as patching and bonding, along with repair monitoring and automation, case studies, and emerging trends in composite repair technologies.
结构聚合物复合材料(SPC)由于其轻量化潜力、优异的抗疲劳和抗冲击性能、优越的阻尼性能以及高强度和刚度性能,在汽车工业中越来越受欢迎。汽车行业对提高SPC的维修方法表现出浓厚的兴趣。然而,由于SPC设计规则、生产工艺和连接技术不成熟,复合材料汽车零部件的安全性和效率将在很大程度上依赖于有效的结构维护和维修。尽管它的重要性,在过去的几十年里,在修复SPC材料方面取得了最小的进展。因此,迫切需要加强复合材料修复实践并促进这一重要领域的创新。本文旨在解决这一需求,重点关注维修技术,并涵盖与汽车工业中SPC材料相关的各种最先进的加工步骤。该综述概述了复合材料修复的几个关键方面,包括用于损伤评估的先进无损检测(NDT)方法、结构复合材料的加工和表面处理技术。此外,它还深入研究了切割修复方法,如修补和粘合,以及修复监测和自动化,案例研究和复合修复技术的新兴趋势。
Establishing interphase with “rigid-flexible coupling” crosslinking network by supramolecular structure to improve interfacial properties of high modulus carbon fiber reinforced polymer composites
Yushan Wu, Hantian Lu, Faxiang Qin, Shan Yang, Peng Xu, Hua-Xin Peng
doi:10.1016/j.compositesb.2024.111968
采用超分子结构建立具有“刚柔耦合”交联网络的界面相,改善高模量碳纤维增强聚合物复合材料的界面性能
Interfacial properties are a key factor influencing the overall performance of carbon fiber reinforced polymer composites (CFRPs). A novel interphase with “rigid-flexible coupling” crosslinking network is established by introducing supramolecule pseudopolyrotaxane (PPR) on the high modulus carbon fiber (HMCF) surface to improve interfacial properties of CFRPs. Our design utilizes the unique molecular necklace structure of PPR composed of β-cyclodextrin (β-CD) and polyetheramine (PEA). Here, hydroxyl-rich β-CD acts as crosslinking sites and catalyst to enhance interfacial crosslinking density and the mobile main chain PEA serves as an internal stress relaxant to dissipate stress, thereby simultaneously improving the stiffness and toughness of the interphase. The resultant CFRPs exhibit excellent interfacial properties with a 90 % rise in interfacial shear strength (IFSS) and 156 % enhancement in transverse fiber bundle test (TFBT) strength in comparison with desized HMCF composites. This work provides a new strategy for preparing carbon fiber reinforced polymer composites with excellent interfacial properties.
界面性能是影响碳纤维增强聚合物复合材料整体性能的关键因素。通过在高模量碳纤维(HMCF)表面引入超分子伪聚己烷(PPR),建立了一种具有“刚柔耦合”交联网络的新型界面相,改善了cfrp的界面性能。我们的设计利用了PPR由β-环糊精(β-CD)和聚乙胺(PEA)组成的独特的分子项链结构。其中,富含羟基的β-CD作为交联位点和催化剂提高界面交联密度,而移动主链PEA作为内应力松弛剂消散应力,从而同时提高界面的刚度和韧性。合成的cfrp具有优异的界面性能,与浆化的HMCF复合材料相比,界面剪切强度(IFSS)提高90%,横向纤维束测试强度(TFBT)提高156%。本工作为制备界面性能优良的碳纤维增强聚合物复合材料提供了新的思路。
Three-Dimensional Cracks Architectural Design Enhances the Sensitivity and Stretchability of Superhydrophobic Strain Sensors
Zhizhe Liu, Qin Jin, Changgeng Zhuang, Peiying He, Yangchengyi Liu, Xiufeng Wang, Xiaoping Ouyang
doi:10.1016/j.compositesb.2024.111978
三维裂缝结构设计提高了超疏水应变传感器的灵敏度和拉伸性能
Crack-based strain sensors, inspired by spider’s sensory system, show high sensitivity, making them suitable for detecting tiny deformation signals from human body. However, enhancing their adaptability to various body deformations and complex hydrated environments remains a challenge. We devise a three-dimensional crack (3D-crack) architectural design with cut-through cracks in the front conductive layer ensure high resistance changing and side network cracks maintain sensing performance under larger tensile strains to balance the trade-off between stretchability and sensitivity while the controlled crack evolution and reduced lateral deformation solve issues of low-fidelity and high-hysteresis. The preparation of the conductive layer involves spontaneous aggregation and migrating of graphite particles and liquid Ecoflex, forming a conductive layer with exceptional superhydrophobicity and excellent waterproof properties. As a result, the developed 3D-cracks strain sensors exhibit excellent sensing performance in terms of a large stretchability (up to 100%), high sensitivity (GF=513.52), low hysteresis (< 0.47%) and low overshoot response (< 5%). The fabricated sensor demonstrates its capability to monitor various body deformation in complex hydrated conditions even underwater, suggesting the potential of this straightforward technique for producing wearable sensors capable of capturing full-range human motion signals in aquatic settings.
基于裂纹的应变传感器,灵感来自蜘蛛的感觉系统,显示出高灵敏度,使其适合检测来自人体的微小变形信号。然而,如何提高它们对各种身体变形和复杂水合环境的适应性仍然是一个挑战。我们设计了一种三维裂缝(3d -裂纹)结构设计,其前缘导电层的贯通裂缝确保高电阻变化,侧网裂缝在较大拉伸应变下保持传感性能,以平衡拉伸性和灵敏度之间的平衡,而控制裂缝演化和减少侧向变形则解决了低保真度和高滞后的问题。导电层的制备涉及石墨颗粒和液体Ecoflex的自发聚集和迁移,形成具有优异超疏水性和优异防水性能的导电层。结果表明,所研制的三维裂纹应变传感器具有大拉伸性(可达100%)、高灵敏度(GF=513.52)、低迟滞(< 0.47%)和低超调响应(< 5%)等优异的传感性能。制造的传感器证明了它在复杂的水合条件下甚至在水下监测各种身体变形的能力,这表明这种简单的技术有潜力生产出能够在水生环境中捕获全方位人体运动信号的可穿戴传感器。
Spider Web-inspired Sericin/Polyacrylamide Composite Hydrogel with Super-low Hysteresis for Monitoring Penalty of Sports Competition
Jingyu Chen, Yunyi Guo, Xueyan Zang, Yangyi Sun, Kunlin Chen
doi:10.1016/j.compositesb.2024.111983
基于蜘蛛网的丝胶/聚丙烯酰胺超低滞后复合水凝胶用于体育比赛判罚监测
Conventional hydrogels often suffer from limitations such as poor hysteresis and low elasticity, significantly restricting their applications and service life. To address these issues, a spider web-inspired super-low hysteresis interpenetrating network hydrogel is designed using a straightforward in-situ thermal polymerization process. Stretching repeatedly within the range of human motion strain, this hydrogel can be rapidly restored to its original form using the formation of multiple hydrogen bonds and the introduction of the molecular spring structure of the β-sheet and α-helix in sericin, which means the service life of the hydrogel is increased imperceptibly. In addition, the sensitive sensing properties of the hydrogel allow for rapid feedback on the movement of human joints, making it possible to apply to considerably sophisticated human motion monitoring requiring rapid response. This kind of hydrogel with super-low hysteresis (1.65%, ε=100%), transparency (88.84% in 500 nm), rapid response (≈173 ms) and excellent sensitivity (GF=2.88 in the strain range of 0-180%) has great application prospects in intelligent judgment in sports competition and human body monitoring.
传统的水凝胶往往存在滞后性差、弹性低等局限性,严重制约了其应用和使用寿命。为了解决这些问题,采用直接的原位热聚合工艺设计了一种受蜘蛛网启发的超低滞后互穿网络水凝胶。这种水凝胶在人体运动应变范围内反复拉伸,通过形成多个氢键,并引入丝胶中β-片和α-螺旋的分子弹簧结构,可以迅速恢复到原来的形态,这意味着水凝胶的使用寿命在无形中得到了提高。此外,水凝胶的敏感传感特性允许对人体关节的运动进行快速反馈,从而可以应用于需要快速响应的相当复杂的人体运动监测。该水凝胶具有超低迟滞(1.65%,ε=100%)、500 nm透明度(88.84%)、快速响应(≈173 ms)和优异的灵敏度(在0-180%应变范围内GF=2.88)等特点,在体育比赛智能判断和人体监测等方面具有很大的应用前景。