今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 8 篇,Composites Science and Technology 3 篇
Inverse design of irregular architected materials with programmable stiffness based on deep learning
Zhuoyi Wei, Kai Wei, Xujing Yang
doi:10.1016/j.compstruct.2024.118210
基于深度学习的可编程刚度不规则结构材料反设计
Incorporating biological materials-inspired irregularity into architected materials is potential to unfold a wider property or new function space, while the inverse design of irregular architected materials (IAMs) for targeted properties is still challenging, owing to the intricate structure–property bidirectional relationships. Accordingly, here, a data-driven framework is originally developed to design new irregular architected materials with programmable stiffness. In detail, a robust dataset of IAMs, which are constructed from diverse stretch- and bending-dominated building blocks, is created by a randomized strategy, and an end-to-end deep learning model is established, including a forward and an inverse network. The forward predictions reveal that IAMs exactly achieve a wide space of programmable stiffness, especially, including extremely high or low dominant elastic stiffness C11, C22 and C66. More importantly, the deep learning-driven inverse design flexibly and precisely realizes the generation of IAMs, fulfilling the customized stiffness targets. Especially, various stiffness tensors, including isotropic, orthotropic, and anisotropic types, are successfully achieved. The remarkable advantage of the inverse design is that solely through adjusting the frequency hints of building blocks, without mandatory geometrical symmetry, IAMs present the exclusive ability to hit the targeted stiffness. Overall, this work fills the gap in the inverse design of irregular architected materials with programmable stiffness and paves the way for material design via deep learning.
将生物材料启发的不规则性融入建筑材料中,有可能拓展出更广阔的特性或新功能空间,而由于结构与特性之间错综复杂的双向关系,反向设计不规则建筑材料(IAMs)以实现目标特性仍具有挑战性。因此,本文最初开发了一个数据驱动框架,用于设计具有可编程刚度的新型不规则结构材料。具体来说,通过随机策略创建了一个由不同的拉伸和弯曲为主的构件构建而成的稳健的 IAM 数据集,并建立了一个端到端的深度学习模型,包括一个正向和一个反向网络。正向预测结果表明,IAMs 可精确实现广阔的可编程刚度空间,尤其是包括极高或极低的主导弹性刚度 C11、C22 和 C66。更重要的是,深度学习驱动的逆向设计灵活而精确地实现了 IAM 的生成,满足了定制的刚度目标。尤其是成功实现了各向同性、正交各向异性和各向异性等各种刚度张量。逆向设计的显著优势在于,仅通过调整构件的频率暗示,而不强制要求几何对称性,IAMs 就能独一无二地达到目标刚度。总之,这项工作填补了具有可编程刚度的不规则结构材料逆向设计方面的空白,为通过深度学习进行材料设计铺平了道路。
Multiscale analysis of hierarchical flax-epoxy biocomposites with nanostructured interphase by xyloglucan and cellulose nanocrystals
Estelle Doineau, Monica Francesca Pucci, Bernard Cathala, Jean-Charles Benezet, Julien Bras, Nicolas Le Moigne
doi:10.1016/j.compositesa.2024.108270
用木聚糖和纤维素纳米晶体对亚麻-环氧纳米复合材料进行多尺度分析
Natural biological systems feature hierarchical nanostructured architectures achieving high strength and toughness. In this work, the spontaneous adsorption of xyloglucan (XG) and cellulose nanocrystals (CNC) onto flax fabrics is considered to develop hierarchical interphases with improved interfacial adhesion in epoxy-based biocomposites. A multi-scale analysis is carried out, from the nano & micrometric scale with the characterization of fibre surface topography, work of adhesion and interfacial shear strength (IFSS) between flax fibres and epoxy resin, to the macroscopic scale with the transverse mechanical properties of biocomposites. At the fibre scale, XG and CNC increase the surface roughness of flax fibres, as well as their adhesion to epoxy resin with IFSS improved by 60 %, up to 22.3 MPa. At the composite scale, the treatments have a major influence on the cohesion of flax cell walls and microstructure of the biocomposites. Transverse tensile tests reveal both cohesive and adhesive interfacial failure.
自然生物系统具有层次化的纳米结构,具有高强度和韧性。在这项工作中,木葡聚糖(XG)和纤维素纳米晶体(CNC)在亚麻织物上的自发吸附被认为是在环氧基生物复合材料中形成分层界面相并改善界面附着力的方法。从纳米和微米尺度的纤维表面形貌表征、亚麻纤维与环氧树脂之间的粘附功和界面剪切强度(IFSS),到宏观尺度的生物复合材料的横向力学性能,进行了多尺度的分析。在纤维尺度上,XG和CNC提高了亚麻纤维的表面粗糙度,提高了亚麻纤维与环氧树脂的附着力,IFSS提高了60% %,达到22.3 MPa。在复合尺度上,处理对亚麻细胞壁的内聚性和生物复合材料的微观结构有重要影响。横向拉伸试验显示粘接界面破坏和内聚界面破坏。
Machine learning-based determination of Mode II translaminar fracture toughness of composite laminates from simple V-notched shear tests
Cheng Qiu, YiZhuo Gui, Jiwen Ma, Hongwei Song, Jinglei Yang
doi:10.1016/j.compositesa.2024.108233
基于机器学习的复合材料层合板简单v形切口剪切试验II型跨层断裂韧性测定
This paper presents a novel method for measuring the translaminar crack resistance curve of composite laminates under Mode II shear loading. A machine learning (ML)-based approach is utilized to extract the inapparent information of the crack resistance curve from the translaminar shear strength measurements obtained from simple V-notched shear tests. The entire campaign is built on the framework of the Finite Fracture Mechanics (FFM) combined with Finite Element Method (FEM). Special emphasis is made on the nonlinear mechanical behavior of composites under shear stress since the original FFM models are designed for quasi-brittle materials. With the well-trained recurrent neural network model, the Mode II R-curve of composite laminate can be obtained with un-notched and V-notched shear strength values as inputs. Experiments were conducted on carbon fiber-reinforced composites to validate the accuracy of the R-curve obtained by the proposed approach and that by the traditional compact shear test. The successful implementation of the method suggests a more convenient and low-cost way of obtaining this important damage-related parameter for composites.
提出了一种测量复合材料层合板在II型剪切载荷作用下跨层抗裂曲线的新方法。利用基于机器学习(ML)的方法,从简单v形切口剪切试验获得的跨层抗剪强度测量数据中提取抗裂曲线的隐性信息。整个活动是建立在有限断裂力学(FFM)和有限元法(FEM)相结合的框架上的。由于原始的FFM模型是为准脆性材料设计的,因此特别强调了复合材料在剪切应力下的非线性力学行为。利用训练良好的递归神经网络模型,可以得到以无缺口和v缺口剪切强度值为输入的复合材料层合板的II型r曲线。对碳纤维增强复合材料进行了试验,验证了该方法得到的r曲线与传统的致密剪切试验结果的准确性。该方法的成功实现为获得这一与复合材料损伤相关的重要参数提供了一种更方便、更低成本的方法。
Assessment of damage sequence in additive manufactured composite laminates under quasi-static out-of-plane loading
A. Fernández, N. Blanco, D. Trias, N. Gascons
doi:10.1016/j.compositesa.2024.108263
准静态面外载荷下增材复合材料层合板损伤序列评估
The understanding of the impact behaviour of additive manufactured continuous fibre reinforced polymers must start from the analysis of the damage mechanisms. In this investigation, the impact damage in a 3D-printed continuous carbon fibre reinforced polymer is studied by means of quasi-static indentation tests. The coupons are manufactured with Fused Filament Fabrication (FFF) using a thermoplastic resin. Three indentation displacement levels were tested, analysing different phases of the impact using X-ray Computed Tomography. The effects of fibre orientation were considered, establishing a comparison between one laminate with conventional orientations (0, 90, ± 45) and one with disperse orientations. Results show a progressive damage generation influenced by the inherent defects of the manufacturing process, characterized by delamination growth and stiffness reduction. Fibre and matrix breakage only appear at the final stages when the laminate peak load is reached. The considered dispersed laminate shows less delaminated interfaces compared to the conventional one.
对添加剂制造的连续纤维增强聚合物的冲击行为的理解必须从损伤机理的分析开始。采用准静态压痕试验方法,对3d打印连续碳纤维增强聚合物的冲击损伤进行了研究。优惠券是用热塑性树脂熔丝制造(FFF)制造的。测试了三个压痕位移水平,使用x射线计算机断层扫描分析了冲击的不同阶段。考虑了纤维取向的影响,建立了传统取向(0、90、±45)和分散取向的层压板之间的比较。结果表明,受制造过程中固有缺陷的影响,复合材料的损伤是渐进式的,其特征是分层生长和刚度降低。纤维和基体断裂只出现在层压峰值荷载达到的最后阶段。与传统层压板相比,所考虑的分散层压板具有较少的分层界面。
Facile and eco-friendly room-temperature electrical-enhanced technology for conductive circuits electrohydrodynamic-printed directly on textiles with small usage of conductive fillers
Wenjing Guo, Goutam Kumar Dalapati, Jiyong Hu, Vundrala Sumedha Reddy, Xiong Yan, Seeram Ramakrishna
doi:10.1016/j.compositesa.2024.108268
简单和环保的室温电增强技术,用于导电电路,电流体动力学,直接印刷在纺织品上,少量使用导电填料
Flexible printed circuits are crucial for efficiently manufacturing electronic textiles. To achieve high conductivity with small usage of conductive fillers and avoid fabric shrinkages caused by high-temperature curing, an eco-friendly and high-temperature-free technology combining UV curing and chemical sintering with electrohydrodynamic (EHD) printing was innovatively proposed. The process integrating sequence was systematically investigated, along with in-depth analysis on surface morphology, electrical performance and enhancement mechanism. Results show that pre-treating fabrics using chemical sintering agent before EHD printing leads to an approximately parabola-like change in electrical resistance, and the “holes” formed by polymer aggregation deteriorates the uniform morphology of printed conductor. In contrast, treating printed lines by optimized integrating process facilitates the uniform and sufficient 3D-sintered structure. Electrical resistance was remarkably reduced by 93 % and successfully lowered to 1.24 ± 0.32 Ω even with 20 wt% Ag. The variation in resistance remained within 20 % after 3000 bending cycles and within 42 % after 10 washing times, exhibiting outstanding flexibility and washability. Additionally, application of as-prepared conductive circuits in electronic textile devices is demonstrated through the performance of ultra-high-frequency radio frequency identification (UHF RFID) antenna. Significant electrical enhancement based on small usage of conductive fillers in this work provides an efficient and green approach towards high-performance flexible circuits and e-textiles.
柔性印刷电路是高效制造电子纺织品的关键。为了在导电填料用量少的情况下实现高导电性,避免高温固化引起的织物收缩,创新性地提出了一种将UV固化、化学烧结与电流体动力(EHD)印刷相结合的环保无高温技术。系统研究了工艺集成顺序,深入分析了表面形貌、电学性能和增强机理。结果表明,在EHD打印前,化学烧结剂对织物进行预处理,导致织物的电阻呈近似抛物线状变化,聚合物聚集形成的“空穴”破坏了印刷导体的均匀形态。相比之下,通过优化的集成工艺处理打印线条有助于均匀和充分的3d烧结结构。电阻显著降低了93 %,并成功地降低到1.24 ± 0.32 Ω,即使20 wt% Ag。在3000次弯曲循环后,阻力变化保持在20 %以内,在10次洗涤后,阻力变化保持在42 %以内,表现出出色的柔韧性和可洗涤性。此外,通过超高频射频识别(UHF RFID)天线的性能,演示了制备好的导电电路在电子纺织设备中的应用。在这项工作中,基于少量导电填料的显著电增强为高性能柔性电路和电子纺织品提供了一种高效和绿色的方法。
High-performance hybrid glass fibre epoxy composites reinforced with amine functionalised graphene oxide for structural applications
Murniyati A. Mahtar, Ian A. Kinloch, Mark A. Bissett
doi:10.1016/j.compositesa.2024.108265
以胺功能化氧化石墨烯增强的高性能杂化玻璃纤维环氧复合材料用于结构应用
Glass fibre-reinforced epoxy (GFRE) composites have had limited use as structural components in industrial applications (e.g., oil and gas, aerospace and civil infrastructure). The use of nanomaterials, such as graphene, has been explored recently to enhance the mechanical and long-term properties of GFRE to realise their full potential and increase their usage. This study evaluated the tensile, creep, and fatigue behaviour of amine-functionalised graphene oxide (fGO) modified glass fibre/epoxy laminate composites. A spray coating technique was used to coat the fGO particles onto the glass fibre surface, and epoxy composite laminates were manufactured using the vacuum resin infusion method. Creep and fatigue testing were performed under a load-controlled mode in the tension direction. Adding fGO within the composites significantly improves the static, creep, and fatigue properties of the fGO-GFRE composites at both room and elevated temperatures. It is shown that adding fGO acts as a barrier to microcrack initiation and restrains the macrocrack propagation during cyclic loading under elevated temperatures in the GFRE composites. These factors, therefore, prevent the early delamination of the matrix and fibre interface during cyclic loading, which explains the fatigue life extension observed in the fGO-modified composites. With 0.05 wt% fGO, the fatigue life of the fGO-GFRE composites was extended by 8× and 30× at a maximum stress of 124–151 MPa, in a 90 °C environment compared to the control GFRE composites. While the creep life compared to the control increased by 63×, 103× and 159× with 0.25 wt%, 0.5 wt% and 1 wt% fGO, respectively. These enhancements are attributed to the large surface area, high stiffness, and functional groups present, which provide a stronger bond between the composite phases. These features help restrict the mobility of the polymer chain during the creeping load and act as barriers to fatigue crack propagation, enhancing the composite’s durability. The nanocomposites produced display attractive properties for many possible industrial applications where improved performance is needed while maintaining a minimum cost.
玻璃纤维增强环氧树脂(gfr)复合材料在工业应用(如石油和天然气、航空航天和民用基础设施)中作为结构部件的用途有限。纳米材料的使用,如石墨烯,最近已经被探索,以增强GFRE的机械和长期性能,以充分发挥其潜力并增加其使用。本研究评估了胺功能化氧化石墨烯(fGO)改性玻璃纤维/环氧复合材料的拉伸、蠕变和疲劳性能。采用喷涂技术将氧化石墨烯颗粒涂覆在玻璃纤维表面,采用真空树脂灌注法制备环氧复合材料层压板。在载荷控制模式下进行拉伸方向的蠕变和疲劳试验。在复合材料中添加fGO可显著改善fGO- gfre复合材料在室温和高温下的静态、蠕变和疲劳性能。结果表明,在高温循环加载过程中,添加氧化石墨烯对复合材料的微裂纹萌生起到了屏障作用,抑制了宏观裂纹的扩展。因此,这些因素阻止了循环加载过程中基体和纤维界面的早期分层,这解释了在fgo改性复合材料中观察到的疲劳寿命延长。当fGO含量为0.05 wt%时,fGO-GFRE复合材料在90 °C环境下的最大应力为124-151 MPa时的疲劳寿命比对照GFRE复合材料延长了8倍和30倍。当添加0.25 wt%、0.5 wt%和1 wt%的氧化石墨烯时,蠕变寿命分别比对照提高63倍、103倍和159倍。这些增强归功于大表面积、高刚度和存在的官能团,这些官能团在复合相之间提供了更强的结合。这些特性有助于限制聚合物链在蠕变载荷下的流动性,并作为疲劳裂纹扩展的屏障,提高复合材料的耐久性。所制备的纳米复合材料在许多可能的工业应用中显示出具有吸引力的性能,这些应用需要在保持最低成本的同时提高性能。
Interfacial Si-O coordination for inhibiting the graphite phase enables superior SiC/Nb heterostructure joining by AuNi
Yaotian Yan, Peixin Li, Zilong Zhang, Yaoxuan Wang, Jingkang Zhang, Liang Qiao, Jian Cao, Junlei Qi
doi:10.1016/j.compositesb.2024.111557
界面Si-O配位抑制石墨相,使AuNi连接的SiC/Nb异质结构优越
The reaction between SiC and Ni-based brazing alloy is extremely intense, where the brittle Ni-Si compound and accompanied dissociate graphite phase as the interfacial reaction product in the joint damage the mechanical properties. In this study, the design of "graphite-controlled" heterogeneous integration component structure on SiC surface is developed to weaken the intense reaction of Ni and SiC. The high-quality surface Si-O coordination was successfully achieved by plasma enhanced chemical vapor deposition (PECVD) method at relatively low temperature on SiC, which increases the Si bond strength due to that the higher binding energy of Si-O (451 KJ/mol) than that of Si-C (347 KJ/mol). SiO2 films enhance the mechanical properties of the joint through macro-weak side interface interlocking and micro-stress mismatch regulation. The shear strength of SiC/Nb heterostructure joints by AuNi alloy was increased by 44%, which paves an inspiring way for boosting heterogeneous integration of SiC ceramic components.
SiC与ni基钎焊合金的反应非常激烈,脆性Ni-Si化合物和伴随的游离石墨相作为界面反应产物在接头处破坏了钎焊合金的力学性能。本研究在SiC表面设计了“石墨控制”的非均相集成构件结构,以减弱Ni和SiC的强烈反应。采用等离子体增强化学气相沉积(PECVD)方法,在较低温度下成功地在SiC表面获得了高质量的Si- o配位,由于Si- o的结合能(451 KJ/mol)高于Si- c的结合能(347 KJ/mol),从而提高了Si的结合强度。SiO2薄膜通过宏观弱侧界面联锁和微观应力失配调节提高了接头的力学性能。AuNi合金SiC/Nb异质组织接头的抗剪强度提高了44%,为促进SiC陶瓷构件的非均相集成铺平了道路。
Preparation of highly thermally conductive, flexible and transparent AlOOH/polyimide composite film with high mechanical strength and low coefficient of thermal expansion
Xinjie Ma, Chaohua Peng, Longying Zhao, An Huang, Mengting Wei, Conghui Yuan, Yiting Xu, Birong Zeng, Guorong Chen, Weiang Luo, Lizong Dai
doi:10.1016/j.compositesb.2024.111558
高机械强度、低热膨胀系数的高导热、柔性、透明AlOOH/聚酰亚胺复合薄膜的制备
With the rapid development of next-generation optoelectronic devices, there is urgent demand for transparent and highly thermal conductive polymer film materials exhibiting superior performance. However, achieving a balance among these diverse properties remains a significant challenge. In this study, we propose a solution to this dilemma by introducing AlOOH nanowires into colorless polyimide (CPI) films. AlOOH/CPI composite films were prepared using a blade coating strategy. Remarkably, the in-plane arrangement of AlOOH nanowires within the CPI matrix facilitates the formation of thermal conductivity pathways. The resulting optimized composite film demonstrates a substantially higher in-plane thermal conductivity (3.568 W·m-1·K-1) compared to pure CPI (0.626 W·m-1·K-1), representing a more than fivefold increase. And the through-plane thermal conductivity showed a marginal enhancement. Moreover, due to the smaller length of the AlOOH nanowires (100 nm) in comparison to the wavelength of visible light, 10 wt% AlOOH/CPI composite film maintains a high transparency of 86.7%, which is only 2.7% lower than that of the pure CPI film. Besides, the formation of hydrogen bonds between AlOOH nanowires and the CPI matrix enhances the mechanical properties and dimensional stability of the AlOOH/CPI composite film. The Young's modulus (3.1 GPa) increases to 148% of the original, while the thermal expansion coefficient (33.7 ppm·°C-1) decreases to 73% of the original value. Furthermore, AlOOH/CPI composite films exhibit excellent flexibility, chemical stability, flame retardancy, and electrical insulation property. These remarkable properties render AlOOH/CPI composite films highly promising for application in advanced optoelectronic devices. This study offers valuable insights into the preparation of CPI-based composite films with excellent comprehensive properties.
随着新一代光电器件的快速发展,对透明、高性能、高导热的聚合物薄膜材料的需求日益迫切。然而,实现这些不同属性之间的平衡仍然是一个重大挑战。在这项研究中,我们提出了一种解决方案,即将AlOOH纳米线引入无色聚酰亚胺(CPI)薄膜中。采用叶片涂布的方法制备了AlOOH/CPI复合薄膜。值得注意的是,AlOOH纳米线在CPI基体内的平面排列有利于热导通路的形成。与纯CPI (0.626 W·m-1·K-1)相比,优化后的复合薄膜具有更高的面内导热系数(3.568 W·m-1·K-1),提高了5倍以上。通过面导热系数略有提高。此外,由于AlOOH纳米线的长度(100 nm)相对于可见光波长更短,10 wt%的AlOOH/CPI复合膜保持了86.7%的高透明度,仅比纯CPI膜低2.7%。此外,AlOOH纳米线与CPI基体之间形成氢键,增强了AlOOH/CPI复合膜的力学性能和尺寸稳定性。杨氏模量(3.1 GPa)增加到原来的148%,而热膨胀系数(33.7 ppm·°C-1)降低到原来的73%。此外,AlOOH/CPI复合薄膜具有优异的柔韧性、化学稳定性、阻燃性和电绝缘性能。这些显著的性能使得AlOOH/CPI复合薄膜在先进光电器件中的应用前景非常广阔。本研究为制备综合性能优良的cpi基复合薄膜提供了有价值的见解。
Promising cellulose-based aerogel composites: Preparation methods and advanced applications
Tian Mai, Pei-Ling Wang, Ming-Guo Ma
doi:10.1016/j.compositesb.2024.111559
纤维素基气凝胶复合材料:制备方法及先进应用
Cellulose aerogels are considered to be potential multifunctional materials due to the characteristics of a wide range of sources, biocompatibility, and porous properties. However, pure cellulose aerogels are difficult to meet the needs of actual production due to limited functionalization. The preparation of cellulose aerogel composites by functional modification of cellulose is a profitable method to improve the properties of cellulose aerogels. The aim of this review is to highlight the latest trends and scientific achievements of cellulose aerogel composites. Cellulose aerogel composites are reviewed from two different aspects, including preparation methods and potential applications (such as water pollutant treatment, piezoresistive sensor, and thermal insulation). In addition, Because the mechanism and properties of materials will directly affect the applications, we also discussed the mechanism (such as electrostatic interaction, coordination, and physical entanglement) and properties (such as density, specific surface area, and mechanical strength) of cellulose aerogel composites, and looked forward to future work. We believe that this review will be helpful for the future development of cellulose aerogel composites.
纤维素气凝胶由于其来源广泛、生物相容性和多孔性等特点,被认为是一种潜在的多功能材料。然而,纯纤维素气凝胶由于官能化程度有限,难以满足实际生产的需要。通过对纤维素进行功能改性制备纤维素气凝胶复合材料是改善纤维素气凝胶性能的有效方法。本文综述了纤维素气凝胶复合材料的最新发展趋势和科研成果。综述了纤维素气凝胶复合材料的制备方法和应用前景(如水污染物处理、压阻传感器和保温材料等)。此外,由于材料的机理和性能将直接影响应用,我们还讨论了纤维素气凝胶复合材料的机理(如静电相互作用、配位、物理纠缠)和性能(如密度、比表面积、机械强度),并展望了未来的工作。本文的研究对纤维素气凝胶复合材料的发展具有一定的指导意义。
Multi-scale design of ultra-high performance concrete (UHPC) composites with centroplasm theory
Dingqiang Fan, Jian-Xin Lu, Kangning Liu, Jiaxing Ban, Rui Yu, Chi Sun Poon
doi:10.1016/j.compositesb.2024.111562
基于质心理论的超高性能混凝土复合材料多尺度设计
Designing ultra-high performance concrete (UHPC) composition is critical for optimal performance, but current methods have limitations in addressing chemical interactions and multi-scale characteristics. Therefore, this study introduced a novel multi-scale design method by combining the packing model and centroplasm theory. Three scales of design were integrated into this method: 1) firstly, micro centroplasm loop thickness (MCLT, water film) was incorporated into the modified Andreasen and Andersen model to optimize the mixture of UHPC paste; 2) then the optimized UHPC paste was progressed to further design UHPC mortar through sub centroplasm loop thickness (SCLT); 3) finally, steel fibers were involved into the designed UHPC mortar for the strength enhancement. The results showed that increasing MCLT promoted the degree of cement hydration. At a MCLT of 0.02 μm, the designed UHPC paste exhibited a higher density of C-S-H gel. The increased SCLT enhanced workability, compressive strength, and reduced porosity in UHPC mortar. Optimal comprehensive performance, with a workability of 230 mm and compressive strength of 168.9 MPa, was achieved with 2.0 vol.% steel fibers and 30 μm SCLT. The results demonstrated the existence of optimal distances between particles at different scales in the UHPC system, emphasizing the importance of precise design. This work refined the fundamental design theory of UHPC composites by packing theory, film theory, cement hydration and centroplasm effects.
设计超高性能混凝土(UHPC)组合物对于优化性能至关重要,但目前的方法在处理化学相互作用和多尺度特性方面存在局限性。因此,本研究提出了一种将包装模型与质心理论相结合的新型多尺度设计方法。该方法整合了三个设计尺度:1)首先,将微质心环厚度(MCLT,水膜)纳入改进的Andreasen和Andersen模型中,对UHPC膏体的混合料进行优化;2)然后对优化后的UHPC砂浆进行进一步设计,通过亚质心环厚度(SCLT)对UHPC砂浆进行进一步设计;3)最后,在设计的UHPC砂浆中加入钢纤维进行强度增强。结果表明,mct的增加促进了水泥水化程度的提高。在mct为0.02 μm时,所设计的UHPC膏体表现出更高的C-S-H凝胶密度。增加的SCLT提高了UHPC砂浆的和易性、抗压强度和降低了孔隙率。以2.0 vol.%的钢纤维和30 μm的SCLT为材料,可加工性为230 mm,抗压强度为168.9 MPa,综合性能最佳。结果表明,在不同尺度下,UHPC系统存在最佳粒子间距,强调了精确设计的重要性。从填料理论、膜理论、水泥水化和质心效应等方面完善了UHPC复合材料的基本设计理论。
Dodecyl Sulfate Ions Co-Intercalated Nickel Cobalt Carbonate Hydroxide with Multiwall Carbon Nanotube: An Advanced Catalyst for the Electrochemical Detection of Nilutamide
Thangavelu Sakthi Priya, Muthumariappan Akilarasan, Tse-Wei Chen, Shen-Ming Chen, Thangavelu Kokulnathan, Wasif Farooq, Yun-Hao Chang
doi:10.1016/j.compositesb.2024.111564
十二烷基硫酸盐离子与多壁碳纳米管共插层碳酸镍钴氢氧化物:一种用于尼鲁胺电化学检测的新型催化剂
Nilutamide (NLD) serves as a crucial anti-androgen drug for prostate cancer treatment; however, its elevated presence poses ecological risks. Monitoring NLD in environmental and biological samples is imperative. Layered double hydroxide (LDH) stands out as an intriguing electrocatalyst material, and this study focuses on enhancing its properties by hydrothermally preparing a hydrophobic LDH through co-intercalation of dodecyl sulfate anion in nickel cobalt carbonate hydroxide (NCCH). The catalytic performance is further improved by incorporating multiwall carbon nanotubes (MWCNT) to achieve precision and sensitivity in the electrochemical detection of NLD. The resulting NCCH/MWCNT-based electrochemical sensor demonstrates excellent structural, functional, and morphological characteristics verified by various spectroscopic techniques. Electrochemical analyses reveal impressive results, including a low detection limit (0.001 μM), quantification limit (0.0036 μM), two linear ranges (0.01 to 59.19 μM and 59.19 to 537.19 μM), and high sensitivity (3.957 μA μM−1cm−2). The practical utility is confirmed through successful monitoring of NLD in environmental and biological samples with satisfactory recoveries. In conclusion, NCCH/MWCNT emerges as a superior electrode material for the selective detection of NLD, showcasing its potential in environmental monitoring and clinical applications.
尼鲁胺(NLD)是治疗前列腺癌的重要抗雄激素药物;然而,它的存在带来了生态风险。监测环境和生物样品中的全民盟是必要的。层状双氢氧化物(LDH)是一种引人注目的电催化剂材料,本研究主要通过在碳酸镍钴氢氧化物(NCCH)中共插十二烷基硫酸盐阴离子,通过水热法制备疏水性LDH来增强其性能。通过加入多壁碳纳米管(MWCNT)进一步提高了催化性能,实现了NLD电化学检测的精度和灵敏度。由此产生的基于NCCH/ mwcnts的电化学传感器具有优异的结构、功能和形态特征,并通过各种光谱技术进行了验证。电化学分析结果令人印象深刻,包括低检测限(0.001 μM),定量限(0.0036 μM),两个线性范围(0.01 ~ 59.19 μM和59.19 ~ 537.19 μM),高灵敏度(3.957 μA μM−1cm−2)。通过成功监测环境和生物样品中的NLD并获得满意的回收率,证实了该方法的实用性。综上所述,NCCH/MWCNT作为选择性检测NLD的优越电极材料,在环境监测和临床应用中显示出其潜力。
Fabricating High-Performance Biomedical PLLA/PVDF Blend Micro Bone Screws through in situ Structuring of Oriented PVDF Submicron Fibers in Microinjection Molding
Jiayu Tan, Tao Li, Yeping Xie, Meiqiong Chen, Li Li, Chuhong Zhang, Yinghong Chen, Long Pang, Chunsen Zhang, Yinghao Li, Xin Tang
doi:10.1016/j.compositesb.2024.111567
定向PVDF亚微米纤维原位成形制备高性能医用PLLA/PVDF共混微骨螺钉
Poly(L-lactide) (PLLA) is regarded as a polymer with excellent biocompatibility, but its inherent brittleness property greatly restricts its application in the biomedical engineering field. Blending PLLA with other polymers is one of the sufficiently viable methods of property improvement. In this paper, the Poly(L-lactide) (PLLA)/Polyvinylidene fluoride (PVDF) blend was first prepared by melt-compounding, and then microinjection molded into the blend micro bone screw with high strength and toughness. The experimental results show that the PVDF dispersed phases could in situ form the highly oriented fibers with shish-kebab structures under the effect of strong shear stress field of microinjection molding along flow direction. These parallelly aligning PVDF fibers could simultaneously realize the significant enhancement in both toughness and strength of the micro bone screw. Specifically, in the bending test the blend micro bone screw with oriented PVDF fibers can withstand the compression displacement of nearly 2 mm, while the neat PLLA one would break within only 0.5 mm displacement. In addition, a bending recovery phenomenon was observed in the load-displacement curve of the blend, demonstrating the mechanical transition from brittle fracture to ductile fracture. Moreover, with addition of 30% PVDF, the elongation at break increases from 7.8% to 57.8%, while the tensile strength increases from 60.9 MPa to 74.3 MPa. The PLLA/PVDF micro screws possess better toughness and excellent biocompatibility compared to pure PLLA products. They also exhibit great potential for stimulating the proliferation of cells through piezoelectric output, opening up new possibilities for the development of next-generation fracture fixation materials.
聚l -丙交酯(PLLA)被认为是一种具有良好生物相容性的聚合物,但其固有的脆性极大地限制了其在生物医学工程领域的应用。PLLA与其他聚合物共混是一种改善性能的可行方法。本文首先采用熔融复合法制备了聚l -丙交酯(PLLA)/聚偏氟乙烯(PVDF)共混物,然后将其微注塑成型制成高强度、高韧性的共混物微骨螺钉。实验结果表明,在沿流动方向的强剪切应力场作用下,聚偏氟乙烯分散相可以原位形成具有羊肉串结构的高取向纤维。这些平行排列的PVDF纤维可以同时实现微骨螺钉韧性和强度的显著增强。在弯曲试验中,定向PVDF纤维共混微骨螺钉可以承受近2mm的压缩位移,而纯PLLA微骨螺钉在0.5 mm的位移内就会断裂。此外,共混物的载荷-位移曲线出现了弯曲恢复现象,表明其从脆性断裂向韧性断裂的力学转变。添加30% PVDF后,断裂伸长率由7.8%提高到57.8%,抗拉强度由60.9 MPa提高到74.3 MPa。与纯PLLA产品相比,PLLA/PVDF微螺钉具有更好的韧性和良好的生物相容性。它们还显示出通过压电输出刺 激细胞增殖的巨大潜力,为开发下一代骨折固定材料开辟了新的可能性。
Effect of low temperature on interlaminar fracture toughness of multi-directional CFRP and CFRP-steel interfaces
J. Koord, C. Hühne
doi:10.1016/j.compositesb.2024.111540
低温对多向CFRP及CFRP-钢界面层间断裂韧性的影响
Delamination is the dominant failure type in FMLs, particularly when combining CFRP and steel. Practical applications usually contain multi-directional interfaces. Therefore, delamination of multi-material and multi-directional interfaces is investigated using the DCB and ENF setups. Analysis of such interfaces requires asymmetric layups. Thus, thermal residual stresses (TRS) build up. Effects of TRS are corrected to compare true fracture toughness values, since neglecting TRS can result in mispredictions of up to 200 %. The ply orientation at the delamination interface affects the fracture toughness of monolithic and hybrid interfaces. In general, hybrid interfaces exhibit slightly lower interface properties compared to monolithic interfaces. While mode I behavior appears mostly unaffected by temperature, mode II fracture toughness slightly increases with decreasing temperature.
分层是FMLs的主要破坏类型,特别是当CFRP与钢结合时。实际应用通常包含多向接口。因此,使用DCB和ENF装置研究了多材料和多向界面的分层。对这种接口的分析需要不对称布局。因此,热残余应力(TRS)的建立。由于忽略TRS可能导致高达200%的错误预测,因此对TRS的影响进行了校正,以比较真实的断裂韧性值。分层界面处的层向影响整体和杂化界面的断裂韧性。一般来说,混合接口比单片接口表现出稍低的接口属性。ⅰ型断裂韧性基本不受温度的影响,而ⅱ型断裂韧性随温度的降低略有增加。
Fatigue performance and damage characterisation of ultra-thin tow-based discontinuous tape composites
Ioannis Katsivalis, Monica Norrby, Florence Moreau, Erik Kullgren, Soraia Pimenta, Dan Zenkert, Leif E. Asp
doi:10.1016/j.compositesb.2024.111553
超薄带基不连续带复合材料的疲劳性能与损伤特性
Tow-cased discontinuous composites are an attractive alternative material to conventional continuous composites as they offer in-plane isotropy, enhanced manufacturability allowing to achieve complex 3D shapes with high curvatures and local reinforcement in critical areas, while also maintaining high strength and stiffness, therefore expanding the design space significantly. In addition, the use of ultra-thin tapes and optimised manufacturing methods can increase the mechanical properties even further and change the damage mechanisms. Fatigue, however, could be a limiting design factor, as the fatigue behaviour of these materials has not been fully characterised. This work presents a complete study on the fatigue response of ultra-thin tow-based discontinuous composites: fatigue S-N curves are measured, and the damage and failure mechanisms are characterised utilising optical and scanning electron microscopy. Finally, a critical interpretation of the results is also presented by comparing the performance of ultra-thin tow-based discontinuous composites against other similar fibre reinforced composites and metals. It is shown that the optimised manufacturing methods combined with low tape thickness leads to enhanced quasi-isotropic fatigue performance. In addition, the fatigue limit was raised significantly compared to other discontinuous composites, and the tow-based discontinuous composites outperformed their metal counterparts when the results were normalised with density.
拖套不连续复合材料是传统连续复合材料的一种有吸引力的替代材料,因为它们提供平面内各向同性,增强的可制造性,允许实现具有高曲率和关键区域局部增强的复杂3D形状,同时还保持高强度和刚度,因此显着扩大了设计空间。此外,超薄胶带的使用和优化的制造方法可以进一步提高机械性能,改变损伤机制。然而,疲劳可能是一个限制设计因素,因为这些材料的疲劳行为尚未完全表征。本研究对超薄带基不连续复合材料的疲劳响应进行了完整的研究:测量了疲劳S-N曲线,并利用光学和扫描电子显微镜对损伤和破坏机制进行了表征。最后,通过比较超薄带基不连续复合材料与其他类似纤维增强复合材料和金属的性能,也提出了对结果的关键解释。结果表明,优化后的制造方法与低胶带厚度相结合,提高了准各向同性疲劳性能。此外,与其他不连续复合材料相比,疲劳极限显著提高,当结果与密度归一化时,拖基不连续复合材料的性能优于金属同类材料。
Enhanced Ultraviolet Aging Resistance of Epoxy Resins through Surface Enrichment Achieved by Fluorinated Graphene Oxide@CeO2
Bin Du, Nanqing Chen, Guodong Zhang, Yun Chen, Bin Gao, Liqing Liu, Yushun Zhao
doi:10.1016/j.compscitech.2024.110655
氟化石墨烯表面富集增强环氧树脂抗紫外线老化性能Oxide@CeO2
Fluorinated graphene oxide@CeO2 (FGO@CeO2) was synthesized using an in-situ growth method and incorporated as a filler into epoxy resins to improve their UV aging resistance. On UV irradiation, it facilitated the surface enrichment of the modified epoxy resin (MEP), forming a UV-blocking layer. Incorporating FGO@CeO2 induced n→π* electronic transitions within the MEP and lowered the electronic excitation threshold, expanding the UV spectral absorption band and enhancing the UV absorption intensity. A 785% increase in the UV absorption capacity was achieved in the MEP compared with that in the pristine epoxy resin. After 300 h of UV exposure, the photothermal temperature rise in the MEP was 13.67±2°C higher than that in pure epoxy resin.
采用原位生长法合成了氟化石墨烯oxide@CeO2 (FGO@CeO2),并将其作为填料掺入环氧树脂中,以提高其抗紫外线老化性能。在紫外线照射下,它有利于改性环氧树脂(MEP)的表面富集,形成一层紫外线阻挡层。引入FGO@CeO2诱导了MEP内的n→π*电子跃迁,降低了电子激发阈值,扩大了紫外光谱吸收带,增强了紫外吸收强度。与原始环氧树脂相比,MEP的紫外吸收能力提高了785%。紫外线照射300 h后,MEP的光热温升比纯环氧树脂高13.67±2℃。
A novel multiscale prediction strategy for simulating the progressive damage behavior of plain-woven bamboo fabrics reinforced epoxy resin composites
Hang Yao, Tian Bai, Xiuwen He, Qingxiang Wang, Shaohua Gu, Sheldon Q. Shi, Jie Yan, Jiqing Lu, Dong Wang, Guangping Han, Wanli Cheng
doi:10.1016/j.compscitech.2024.110662
一种模拟平编竹编织物增强环氧树脂复合材料渐进损伤行为的多尺度预测策略
This study proposed a novel multiscale prediction strategy, including mesoscale and macroscale damage evolution modeling, to investigate the effective properties and progressive damage failure behavior of plain-woven reinforced composites (PWRCs) under various external loads (tension, compression). A high-precision mesoscale representative volume element (RVE) that could accurately describe the local mechanical behavior of PWRCs was developed by combining experimental characterization (scanning electron microscope and X-ray computed tomography) and numerical simulation. To solve the problem of inaccurate prediction results caused by multiscale characteristics and complex stress changes in the damaged area of PWRCs, the strain-based 3D Hashin failure criterion and the multiscale damage models were used to predict the damage initiation and evolution of mesoscale reinforcement (bamboo fiber yarn bundle) and macroscale composites, respectively. Considering the damage evolution law of isotropic materials, a damage model based on the Von Mises criterion was used to characterize the damage initiation and evolution of mesoscale matrix epoxy resin (EP) under external loading. The effective properties and mechanical behavior of the PWRCs were transferred from mesoscale to macroscale through the progressive homogenization method. The bilinear constitutive relationship of the mixed-mode cohesive element was used to characterize the interlaminar failure of the PWRCs. Finally, the corresponding mechanical characterization (tension, compression) of the PWRCs was carried out. Moreover, the experimental results were highly consistent with the simulation results, verifying the reliability of the novel multiscale prediction strategy in investigating the mechanical response of the PWRCs at multiple scales and revealing the damage mechanism of the PWRCs.
本研究提出了一种新的多尺度预测策略,包括中尺度和宏观尺度损伤演化模型,以研究在不同外部载荷(拉、压)作用下平纹编织增强复合材料(PWRCs)的有效性能和渐进损伤破坏行为。通过实验表征(扫描电镜和x射线计算机断层扫描)和数值模拟相结合,建立了能够准确描述PWRCs局部力学行为的高精度中尺度代表性体积元(RVE)。为解决PWRCs损伤区域多尺度特征和复杂应力变化导致预测结果不准确的问题,采用基于应变的三维Hashin破坏准则和多尺度损伤模型分别对中尺度增强材料(竹纤维纱束)和宏观尺度复合材料的损伤起裂和演化进行了预测。考虑各向同性材料的损伤演化规律,采用基于Von Mises准则的损伤模型来表征中尺度环氧树脂(EP)在外载荷作用下的损伤起裂与演化过程。PWRCs的有效性能和力学行为通过渐进式均匀化方法从中尺度转移到宏观尺度。采用混合模内聚单元的双线性本构关系来表征PWRCs层间破坏。最后,对PWRCs进行了相应的力学表征(拉伸、压缩)。实验结果与仿真结果高度吻合,验证了该多尺度预测策略在研究PWRCs多尺度力学响应、揭示PWRCs损伤机理方面的可靠性。
Study of Quasi-static Tensile and Compressive Behaviors of Laminated Bamboo under Service Temperature
Shanyue Guan, Jiucheng Zhao, Xiangyu Zong, Liya Tian, Shizhong Zhang, Hongwei Zhao
doi:10.1016/j.compscitech.2024.110663
使用温度下层合竹材准静态拉伸压缩性能研究
Laminated bamboo presents significant potential for applications in the construction industry. The stress-strain relationship and failure mechanism of laminated bamboo across the service temperature range, spanning from low to high temperatures, remain incompletely elucidated. Addressing this research gap, this paper conducts experiments on tension and compression of laminated bamboo in both parallel to grain direction and perpendicular to grain direction across an extensive temperature range of -40 to 80 °C. Temperature reduction factors according to Eurocode 5 are established, followed by adjustments based on RO constitutive model. Subsequently, a two-section constitutive model for laminated bamboo materials under service temperature is developed. This model is designed to accurately describe the stress-strain relationship of laminated bamboo in various temperature environments. The constitutive model proposed in this paper adeptly predicts the strain hardening behavior of laminated bamboo during compression, demonstrating high accuracy post-yield stress and addressing the non-convergence issue prevalent in most existing models. Additionally, the influence of temperature on fracture mechanism was explored using Scanning Electron Microscopy (SEM). The study delves deeply into the fundamental reasons behind temperature's effect on the mechanical properties of laminated bamboo, examining it from a chemical composition standpoint. This study not only offers significant insights for the application of laminated bamboo in construction projects but also serves as a valuable resource for advancing the understanding of laminated bamboo's mechanical behavior under various temperature conditions. The findings are crucial for architects, engineers, and material scientists, guiding them in optimizing the use of laminated bamboo in sustainable building practices and enhancing the structural integrity of bamboo-based construction.
层压竹子在建筑工业中具有巨大的应用潜力。在低温到高温的使用温度范围内,叠层竹材的应力-应变关系和破坏机制尚未完全阐明。针对这一研究空白,本文在-40 ~ 80°C的广泛温度范围内,对竹片在平行于晶粒方向和垂直于晶粒方向上的拉伸和压缩进行了实验。建立了符合欧洲规范5的降温系数,并根据RO本构模型进行了调整。在此基础上,建立了竹材复合材料在使用温度下的两段本构模型。该模型旨在准确描述叠层竹在不同温度环境下的应力-应变关系。本文提出的本构模型熟练地预测了叠层竹在压缩过程中的应变硬化行为,具有较高的屈服后应力精度,解决了大多数现有模型普遍存在的不收敛问题。此外,利用扫描电镜(SEM)研究了温度对断裂机理的影响。本研究从化学成分的角度,深入探讨了温度对叠层竹材机械性能影响的根本原因。本研究不仅为叠层竹材在建筑工程中的应用提供了重要的见解,而且为进一步了解叠层竹材在不同温度条件下的力学行为提供了宝贵的资源。这一发现对建筑师、工程师和材料科学家来说至关重要,可以指导他们在可持续建筑实践中优化层压竹的使用,并提高竹基建筑的结构完整性。