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【新文速递】2023年10月15日复合材料SCI期刊最新文章

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今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Science and Technology 2 篇

Composite Structures

Fatigue life improvement mechanisms of CFRP/Al hybrid joints – Load sharing study using a digital image correlation technique

He Zongkai, Zheng Gang, Luo Quantian, Li Qing, Sun Guangyong

doi:10.1016/j.compstruct.2023.117625

CFRP/Al复合接头疲劳寿命提高机理——基于数字图像相关技术的载荷分担研究

In comparison with an adhesive joint, a hybrid joint often provides a more effective and reliable way to meet heightened safety requirements in engineering like FAA AC 20-107B. Nevertheless, its fatigue failure characterization, life improvement mechanism and engineering design approach have been understudied as compared to the static loading condition. This study aims to characterize the failure mechanisms by use of the digital image correlation (DIC) technique for elucidating the load sharing phenomenon of hybrid joints in the course of fatigue failure. In the study, bonded, riveted and hybrid joints were tested under static and fatigue loading conditions. To explore different mechanical behaviors of hybrid joints, two types of adhesives with an evident difference in modulus were selected to fabricate the joints. The fatigue life of an adhesive layer and that of the hybrid joint were separately studied to explore the means for life improvement. It is shown that the fatigue life of the hybrid joint can be significantly improved as a result of load sharing by rivets. The improvement of the fatigue life could reach 5 to 13 folders for the hybrid joint due to the load sharing, whereas its improvement ratio was only 1 to 2 times when the adhesive and the rivet were independent. By considering the overlap area as an effective region for design of rivet group, an optimal stiffness can be obtained for the hybrid joint. This study clearly presents two completely different fatigue failure processes for hybrid joints and illustrates the improvement mechanisms of fatigue life, thereby providing useful guidance for optimal design of hybrid joints.

与粘合接头相比,混合接头通常提供更有效、更可靠的方式来满足FAA AC 20-107B等工程中更高的安全要求。然而,与静态载荷相比,其疲劳失效特征、寿命提高机制和工程设计方法研究尚不充分。本研究旨在利用数字图像相关(DIC)技术表征混合接头在疲劳破坏过程中的载荷分担现象。在研究中,测试了粘接、铆接和混合连接在静态和疲劳载荷条件下的性能。为了探究混合接头的不同力学行为,选择了两种模量差异明显的胶粘剂进行混合接头的制备。分别对粘接层疲劳寿命和混合接头疲劳寿命进行了研究,探讨了提高粘接层疲劳寿命的方法。结果表明,铆钉的载荷分担可以显著提高混合接头的疲劳寿命。载荷分担可使混合接头的疲劳寿命提高5 ~ 13倍,而胶粘剂和铆钉独立时的疲劳寿命提高率仅为1 ~ 2倍。将重叠区域作为铆钉组设计的有效区域,可获得混合连接的最优刚度。本研究清晰地揭示了混合接头的两种完全不同的疲劳失效过程,阐明了混合接头疲劳寿命的提高机理,为混合接头的优化设计提供了有益的指导。


Impact of parametric variation to achieve extreme mechanical metamaterials through topology optimization

Saurabh Shubham, Gupta Abhinav, Chowdhury Rajib

doi:10.1016/j.compstruct.2023.117611

影响参数变化,通过拓扑优化实现极端力学超材料

Metamaterials are manufactured structures having extreme properties which do not exist in nature. Topology optimization(TO) provides an excellent alternative to the intuition-based homogenization approach used in commercial packages for automating the design of metamaterials. However, multiple topological parameters must be decided to get the tailored effective properties. This research aims to study the optimum parameters to be used in TO for developing incompressible material. To achieve this, we design microstructures to maximize bulk modulus. Various parametric studies are performed by varying topological parameters such as volume fraction, penalization power, filter radius, mesh size and initial design. In addition to this, the combinations of these parameters are also investigated. These studies will be helpful for the design of incompressible metamaterials. The bulk modulus for topologically optimized designs approaches the Hashin–Shtrikman upper bound(HSUB). The results show that appropriate parameter selection can significantly improve the microstructure’s incompressibility. Such materials can have potential applications in designing aerospace and energy-absorbing components.

超材料是具有自然界中不存在的极端特性的人造结构。拓扑优化(TO)为用于超材料自动化设计的商业封装中使用的基于直觉的均质化方法提供了一个极好的替代方案。然而,为了获得定制化的有效性质,必须确定多个拓扑参数。本研究的目的是研究可用于不可压缩材料开发的最佳参数。为了实现这一目标,我们设计微结构以最大化体积模量。通过不同的拓扑参数,如体积分数、惩罚功率、过滤半径、网格尺寸和初始设计,进行各种参数研究。除此之外,还研究了这些参数的组合。这些研究将有助于不可压缩超材料的设计。拓扑优化设计的体积模量接近Hashin-Shtrikman上限(HSUB)。结果表明,适当的参数选择可以显著改善微结构的不可压缩性。这种材料在设计航空航天和吸能部件方面具有潜在的应用前景。


A progressive damage model for carbon fiber-reinforced polymer laminates subjected to fastener pull-through failure

Zhuang Weimin, Zhang Hailun, Wang Enming, Chen Shen, Liu Yang

doi:10.1016/j.compstruct.2023.117623

碳纤维增强聚合物层压板扣件拉穿失效的渐进损伤模型

Most studies on composite joints focus on in-plane bearing mode, while little attention to fastener pull-through failure mode from out-of-plane loads. This paper presents a 3D continuum damage mechanics (CDM) model to investigate and assess the mechanical behaviors of carbon fiber-reinforced polymer (CFRP) laminates subjected to pull-through failure. The proposed model based on the use of intralaminar and interlaminar damage models is established and implemented by means of a user-defined subroutine VUMAT for Abaqus/Explicit. The novelty lies in the material model integrating the thresholds preset by the semianalytical approximation approach, which largely eliminates unnecessary fracture angle enumerations in Puck’s IFF theory, coupled with the simple parabolic interpolation search (SPIS) technique for optimal fracture angle search, considerably reducing the computational burden. Moreover, the numerical results compare well with experiments, effectively replicating the load-displacement response, damage modes, failure behaviors and damaged areas. This study provides an accurate and efficient computational methodology to analyze pull-through failures, enhancing the damage modeling and predictive capabilities for composite joints under out-of-plane loads.

对复合材料接头的研究大多集中在面内承载模式,而对面外载荷作用下紧固件拉穿破坏模式的研究较少。本文提出了一种三维连续损伤力学(CDM)模型,用于研究和评估碳纤维增强聚合物(CFRP)层合板在拉穿破坏下的力学行为。基于层内和层间损伤模型建立了该模型,并利用Abaqus/Explicit的自定义子程序VUMAT实现了该模型。新颖之处在于材料模型集成了由半解析近似方法预设的阈值,这在很大程度上消除了Puck的IFF理论中不必要的断裂角枚举,再加上简单的抛物插值搜索(SPIS)技术进行最佳断裂角搜索,大大减少了计算量。数值结果与实验结果吻合较好,有效地再现了荷载-位移响应、损伤模式、破坏行为和损伤区域。该研究提供了一种准确、高效的计算方法来分析拉穿失效,增强了复合材料接头在面外载荷作用下的损伤建模和预测能力。


Composites Part A: Applied Science and Manufacturing

Measuring the interlaminar fracture toughness of thin carbon fiber/polyamide6 composites using adhesively bonded stiffeners

Simaafrookhteh Sepehr, Tsokanas Panayiotis, Loutas Theodoros, Lomov Stepan V., Ivens Jan

doi:10.1016/j.compositesa.2023.107841

用粘接增强筋测定薄碳纤维/聚酰胺复合材料的层间断裂韧性

The present work investigates the interlaminar fracture toughness of a thin unidirectional carbon fiber-reinforced/polyamide6 (CF/PA6) composite laminate. Aluminum (Al) stiffening beams are adhesively bonded on both sides of the thin laminate to avoid undesirable large deformations during the subsequent double cantilever beam (DCB) tests. Experimentation with various surface treatment techniques and different adhesives is presented, from which it is concluded that the mode I fracture toughness of the CF/PA6 laminate is always higher than the fracture toughness of the adhesives used in this work. Consequently, the crack initiates at the Al–composite interface. A finite element (FE) model is proposed, and quantitative results for the fracture toughness of the laminate are provided (e.g., GIc,ini= 2.1N/mm). Overall, the study highlights the challenges during the adhesive joining of stiffening beams to CF/PA6 surfaces, ways to improve adhesion, and FE simulation as an alternative to measuring the fracture toughness of such thin laminates.

本研究探讨了单向碳纤维增强/聚酰胺6(CF/PA6)复合材料薄层板的层间断裂韧性。铝(Al)加劲梁被粘合在薄层板的两侧,以避免在随后的双悬臂梁(DCB)试验中出现不希望出现的大变形。实验中使用了各种表面处理技术和不同的粘合剂,由此得出结论:CF/PA6 薄片的模式 I 断裂韧度总是高于本实验中使用的粘合剂的断裂韧度。因此,裂纹起始于铝-复合材料界面。我们提出了一个有限元(FE)模型,并提供了层压板断裂韧性的定量结果(如 GIc,ini= 2.1N/mm)。 总之,该研究强调了加劲梁与 CF/PA6 表面粘接过程中的挑战、改善粘接的方法以及 FE 模拟作为测量此类薄层板断裂韧性的替代方法。


An Accelerated Process Optimization Method to Minimize Deformations in Composites Using Theory-guided Probabilistic Machine Learning

Schoenholz Caleb, Zobeiry Navid

doi:10.1016/j.compositesa.2023.107842

一种基于理论指导的概率机器学习的加速复合材料变形优化方法

While aerospace manufacturing and assembly technologies have significantly evolved, challenges persist in mitigating process-induced deformations (PIDs) in composite parts. Physics-based-simulation optimization strategies have been developed to address these challenges. However, they often prove ineffective or inefficient because of the time-consuming, costly, and deterministic characterization efforts they require. This study introduces a novel characterization- and simulation-free optimization approach for predicting and minimizing PIDs in composite parts. The method uses a theory-guided machine learning (TGML) framework, consisting of limited element-level experiments and Gaussian Process Regression (GPR) with integrated closed-form domain knowledge. This paper showcases the effectiveness of the proposed TGML method for two case studies, where an optimal layup and cure cycle are found and validated after a mere six experiments and without any material characterization or simulation efforts. The method presented in this paper aims to offer a cost-efficient and generalizable process optimization procedure to potentially mitigate PIDs in composite parts.

虽然航空航天制造和装配技术有了显著的发展,但在减少复合材料零件的过程引起的变形(pid)方面仍然存在挑战。基于物理的仿真优化策略已经被开发出来以应对这些挑战。然而,由于它们所需要的耗时、昂贵和确定性的表征工作,它们常常被证明是无效的或低效的。本文介绍了一种新的无需表征和仿真的优化方法,用于预测和最小化复合材料零件的pid。该方法采用理论引导的机器学习(TGML)框架,由有限元素级实验和高斯过程回归(GPR)组成,并集成了封闭形式的领域知识。本文展示了两个案例研究中所提出的TGML方法的有效性,其中仅经过六次实验,无需任何材料表征或模拟工作,即可发现并验证最佳铺层和固化周期。本文提出的方法旨在提供一种具有成本效益和可推广的工艺优化程序,以潜在地减轻复合材料零件的pid。


Composites Science and Technology

Nacre-like composites with a soft thermoplastic elastomer matrix

Rajinthan Lucas, Fritz Simon, Galkov Igor, Jiang Liuyin, Fournier Sylvain, Bernard Julien, Meille Sylvain, Doitrand Aurélien, Baeza Guilhem P.

doi:10.1016/j.compscitech.2023.110302

 

具有柔软热塑性弹性体基体的类珍珠复合材料

We produce nacre-like composites made of a soft thermoplastic elastomer matrix reinforced by alumina platelets, as a flexible and healable alternative to stiff brick-and-mortar materials while keeping their characteristic anisotropic microstructure. Materials are manufactured using step-wise deposition and subsequent controlled evaporation of a suspension containing the polymer and the platelets. Well-aligned microstructures loaded from 15 to 65 vol.% in alumina are obtained through hot-pressing densification of the resulting composites. Remarkably, by combining calorimetry and low-field nuclear magnetic resonance techniques, we emphasize that the polymer mobility decreases significantly in spite of a lower degree of cristallinity when the platelet content is increased. This result sheds light on the origin of the limited quality of samples above 45 vol.%, opening new research directions to improve the design of organic nacre-like composites. Tensile, bending and indentation tests on samples containing up to 45 vol.% in platelets are then used to rationalize the mechanical properties variation related to the polymer state. Finally, we show that the addition of 3 vol.% of Fe nanoparticles into the composites is enough to enable their induction heating that we aim to utilize in the future as a contactless healing method.

我们生产由氧化铝片增强的柔软热塑性弹性体基体制成的类珍珠复合材料,作为刚性砂浆材料的柔性和可修复的替代品,同时保持其特征的各向异性微观结构。材料的制造采用逐步沉积和随后的控制蒸发的悬浮液含有聚合物和血小板。通过热压致密化所得到的复合材料,得到了负载从15到65体积%氧化铝的排列良好的微观结构。值得注意的是,通过结合量热法和低场核磁共振技术,我们强调了当血小板含量增加时,聚合物的迁移率显著降低,尽管结晶度降低。这一结果揭示了45 vol.%以上样品质量有限的原因,为改进有机类珍珠复合材料的设计开辟了新的研究方向。拉伸、弯曲和压痕测试的样品含有高达45体积%的血小板,然后用于合理化的机械性能变化相关的聚合物状态。最后,我们表明,在复合材料中添加3vol .%的铁纳米颗粒足以使其感应加热,我们的目标是在未来将其用作非接触式愈合方法。


Electromagnetic functionalization of mechanical lattice to metastructure with oblique incident broadband microwave absorption

Zhang Yuhui, Xu Yinfang, Yu Chen, Lei Han, Zhao Pengzhen, Huang Yixing

doi:10.1016/j.compscitech.2023.110308

 

斜入射宽带微波吸收下机械晶格向元结构的电磁功能化

Electromagnetic functionalization of mechanical lattice is an important method to integrate mechanical and electromagnetic properties into one structure with effective load bearing and broadband microwave absorption. Herein, the gradient lattice metastructure (GLM) is fabricated by dielectric-magnetic lossy nano composite strengthened by carbon fiber and glass fiber reinforced polymer. A large mutation genetic algorithm is developed to optimize the GLM with fine convergence property. Several large mutation modules are incorporated into the program to speed up the optimization process and improve global convergence. The measured −10 dB absorption bandwidth covers 2–5 GHz and 6.5–17.3 GHz while −9.5 dB absorption bandwidth covers 2–17.3 GHz. The oblique incident broadband absorption is achieved from normal incidence to the grazing incidence of 85° in traverse electrical (TE) and traverse magnetic (TM) polarization. Gradient lattice design is effective to overcome systemic oblique incident absorption deterioration originating from enhanced tangential electric field intensity in large incident angles. The nominal tensile strength of GLM reaches 108.4 MPa with maximum flexural load of 1.83 kN. The high electromagnetic and mechanical properties are achieved simultaneously by electromagnetic functionalization of mechanical lattice.

机械晶格的电磁功能化是将力学性能和电磁性能集成为一个结构的重要方法,具有有效的承载和宽带微波吸收能力。本文采用碳纤维和玻璃纤维增强聚合物增强的介电磁性损耗纳米复合材料制备了梯度晶格超结构(GLM)。提出了一种具有优良收敛性的大突变遗传算法。为了加快优化过程,提高全局收敛性,在程序中加入了多个大型突变模块。−10 dB的吸收带宽覆盖2-5 GHz和6.5-17.3 GHz,−9.5 dB的吸收带宽覆盖2-17.3 GHz。斜入射宽带吸收在横电极化(TE)和横磁极化(TM)中实现了从正入射到掠入射85°的斜入射宽带吸收。梯度晶格设计有效地克服了大入射角下切向电场强度增强引起的系统斜入射吸收衰减。GLM的标称抗拉强度为108.4 MPa,最大弯曲载荷为1.83 kN。通过对机械晶格进行电磁功能化,使其同时具有较高的电磁性能和力学性能。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemAbaqusMAGNET疲劳断裂复合材料拓扑优化航空航天裂纹电场理论材料控制试验
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【新文速递】2023年10月9日复合材料SCI期刊最新文章

今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 1 篇Composite StructuresAnalytical study on the behavior of CFRP-concrete bonded joint with a non-rigid end-anchorZhou Hao, Yang Yan, Liu Kai, Huang Tian-li, Ou Ya, Zhang S.S.doi:10.1016/j.compstruct.2023.117609带有非刚性端锚的 CFRP 混凝土粘接接头行为分析研究End-anchors have been widely used to prevent/postpone debonding failures in FRP-strengthened RC structures. The bond behavior between FRP and concrete with end-anchors can be investigated through FRP-concrete bonded joint with such anchors. Existing studies have found that deformation of FRP and the anchor, as well as slip of FRP-concrete interface at the anchored end can happen when the FRP is under external loading; therefore, the simple assumption that end-anchors provide a rigid end to FRP may result in significant overestimations of the bonding stiffness and strength. Against this background, this paper presents an analytical study on the closed-form solution to the full-range bond behavior of CFRP-concrete bonded joint with a non-rigid anchor. The obtained analytical solution was first verified through finite element analyses and test results, and then was adopted in a comprehensive parametric study to investigate the effect of mechanical properties of end-anchors on the overall bond behavior of the joint. This paper provides a better understanding of the bond behavior between FRP and concrete with a non-rigid anchor and shows that the design of such end-anchors should be based on CFRP-concrete interfacial characteristics for a desired bond behavior.端锚已被广泛用于防止/延缓玻璃钢加固 RC 结构的脱粘故障。可以通过带有端锚的 FRP 混凝土粘接接头来研究 FRP 与混凝土之间的粘接行为。现有研究发现,当 FRP 承受外部荷载时,FRP 和锚固件会发生变形,锚固端 FRP 混凝土界面也会发生滑移;因此,简单假定端锚为 FRP 提供刚性端可能会导致对粘结刚度和强度的严重高估。在此背景下,本文对带有非刚性锚固件的 CFRP-混凝土粘接接头的全范围粘接行为的闭式解进行了分析研究。首先通过有限元分析和测试结果验证了所获得的分析解,然后采用该分析解进行了全面的参数研究,探讨了端部锚固件的力学性能对接头整体粘结行为的影响。本文让人们更好地了解了玻璃纤维增强塑料与混凝土之间的非刚性锚固的粘结行为,并表明此类端锚的设计应基于 CFRP-混凝土界面特性,以实现理想的粘结行为。Mechanical properties of a novel hierarchical cellular structure architectured with minimal surfaces and Voronoi-tessellationMu Yanru, Jin Yuan, Ji Han, Wang Weiwei, Zou Sijia, Zhang Chao, Du Jiankedoi:10.1016/j.compstruct.2023.117610用最小表面和 Voronoi 网格构建的新型分层细胞结构的力学特性Hierarchical structures are commonly found in nature due to their combination of low density, exceptional specific properties, and multifunctionality. Inspired by this, we proposed a novel hierarchical cellular structure based on triply periodic minimal surface (TPMS) by connecting two topologically identical and parallel sheets with a series of connecting ribs. A conformal design guideline was provided by describing the mathematical principles behind the generation of such hierarchical cellular structures. Then the designed structures with different configurations were fabricated via laser powder bed fusion (LPBF). Finally, the mechanical performance of the hierarchical cellular structures was analyzed by both experiment and numerical simulation. The dynamic compressive behavior was investigated using a Split Hopkinson pressure bar (SPHB) at a strain rate of 650s-1, and the temperature distribution during tests was monitored using a high-speed infrared camera. As for quasi-static compression tests, it is found that the hierarchical cellular structure had good energy absorption characteristics and relatively low first peak stresses. These results showed that the structure could reduce strain rate hardening effects under dynamic loading, thereby mitigating the increase in first peak stress. The proposed hierarchical cellular structures showed good potential for efficient energy absorption under quasi-static and dynamic compression loadings.由于兼具低密度、特殊性能和多功能性,分层结构在自然界中十分常见。受此启发,我们提出了一种基于三重周期性极小表面(TPMS)的新型分层细胞结构,通过一系列连接肋将两个拓扑相同且平行的薄片连接起来。通过描述生成这种分层蜂窝结构背后的数学原理,我们提供了一个保形设计指南。然后,通过激光粉末熔床(LPBF)制造出不同配置的设计结构。最后,通过实验和数值模拟分析了分层蜂窝结构的机械性能。在应变速率为 650s-1 的条件下,使用分体式霍普金森压力棒(SPHB)研究了动态压缩行为,并使用高速红外摄像机监测了试验过程中的温度分布。在准静态压缩试验中发现,分层蜂窝结构具有良好的能量吸收特性和相对较低的第一峰值应力。这些结果表明,该结构可以降低动态加载下的应变速率硬化效应,从而缓解第一峰值应力的增加。所提出的分层蜂窝结构具有在准静态和动态压缩载荷下高效吸收能量的良好潜力。Composites Part A: Applied Science and ManufacturingTheoretical analysis of phase transition behavior of ALCP/CNT nanocomposites interface by photo and thermal stimulationKim Hongdeok, Choi Joonmyungdoi:10.1016/j.compositesa.2023.107824 光热刺 激下 ALCP/CNT 纳米复合材料界面相变行为的理论分析Azobenzene-containing liquid crystal polymers (ALCPs) functionalised with carbon nanotubes (CNTs) have enormous potential in intelligent devices and soft robotics. This study investigates the phase transition and subcontinuum mechanics occurring at the ALCP/CNT interface under heat and light stimulation using all-atom molecular dynamics (MD) simulations. The results suggest that the strong π-π interaction between azobenzene and CNT directly affects the mechanical behavior due to extremely high interfacial stability. The properties at the interface remain intact even in environments where forced phase transitions are induced by external stimuli. The unique edge-to-face stacking of interfacial azobenzene during isomerization, as well as the co-alignment properties of trans-azobenzene with CNTs in the interfacial region, are the origins of its high stability. The influence of the structural features of the interface on the mechanical behavior during the phase transition is also understood as the load transfer efficiency of each molecular component.与碳纳米管(CNTs)功能化的含偶氮苯液晶聚合物(ALCPs)在智能设备和软机器人领域具有巨大潜力。本研究利用全原子分子动力学(MD)模拟研究了 ALCP/CNT 界面在热和光刺 激下发生的相变和亚连续介质力学。结果表明,由于界面稳定性极高,偶氮苯和 CNT 之间强烈的 π-π 相互作用直接影响了力学行为。即使在外部刺 激诱发强制相变的环境中,界面的特性也能保持不变。界面偶氮苯在异构化过程中独特的边到面堆叠以及反式偶氮苯与 CNT 在界面区的共对准特性是其高稳定性的根源。界面的结构特征对相变过程中机械行为的影响也可以理解为每种分子成分的载荷传递效率。Constructing flame retardant silica nanoparticles through styrene maleic anhydride copolymer grafting for PC/ABS compositesZhang Jingfan, Hua Yifang, Liu Jian, Zhu Tao, Sun Jun, Gu Xiaoyu, Li Hongfei, Zhao Jingmao, Zhang Shengdoi:10.1016/j.compositesa.2023.107825通过苯乙烯-马来酸酐共聚物接枝构建阻燃硅纳米颗粒,用于 PC/ABS 复合材料Organic-inorganic hybrid particles have been prepared by grafting styrene maleic anhydride copolymer (SMA) onto reactive amino-modified silica nanoparticles. The SMA modified SiO2 (SMA-SiO2) was incorporated into polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) composites (4:1, wt%/wt%) with bisphenol A bis (diphenyl phosphate) (BDP) to simultaneously improve the mechanical properties and flame retardancy. The mechanical properties of the sample containing SMA-SiO2 are apparently enhanced compared with samples containing unmodified SiO2. It is found that SMA-SiO2 tends to distribute at the phase interface of PC/ABS, and therefore improves the compatibility between PC and ABS. Besides, the peak of heat release rate (PHRR) and the total smoke production (TSP) of the PC/ABS composites are decreased by the presence of SMA-SiO2. It is suggested that SMA-SiO2 can form a flame retarding shell at the phase interface to protect ABS. In general, both the mechanical properties and flame retardancy are enhanced due to the selective distribution.通过将苯乙烯马来酸酐共聚物(SMA)接枝到活性氨基改性二氧化硅纳米粒子上,制备了有机-无机杂化粒子。将 SMA 改性二氧化硅(SMA-SiO2)加入到聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯(ABS)复合材料(4:1,wt%/wt%)与双酚 A 双(二苯基磷酸酯)(BDP)中,可同时改善其机械性能和阻燃性。与含有未改性 SiO2 的样品相比,含有 SMA-SiO2 的样品的机械性能明显提高。研究发现,SMA-SiO2 倾向于分布在 PC/ABS 的相界面上,因此提高了 PC 与 ABS 的相容性。此外,SMA-SiO2 的存在降低了 PC/ABS 复合材料的热释放率峰值(PHRR)和总烟雾产生量(TSP)。这表明 SMA-SiO2 可在相界面形成阻燃外壳,保护 ABS。总的来说,由于选择性分布,机械性能和阻燃性都得到了提高。Synthesis of melamine cyanuric based flame retardant via hydrogen bond self-assembly and in-situ dispersion strategies for improving comprehensive performance of epoxy resinWang Wei, Liu Yuan, Wang Qidoi:10.1016/j.compositesa.2023.107826通过氢键自组装和原位分散策略合成三聚氰胺基阻燃剂,提高环氧树脂的综合性能The design of flame retardant epoxy resin (EP) with superior smoke suppression, mechanical properties and simple manufacturing process has been very challenging in industry and academia. Herein, we synthesized an amino-rich polyphosphazonitrile microsphere (PZS) to regulate the synthesis of melamine cyanurate (MCA) through hydrogen bond self-assembly and in-situ dispersion strategies for flame retardant EP. The in-situ dispersion strategy effectively alleviates the agglomeration of PZS@MCA assembly units by taking advantage of the viscosity of EP prepolymer. The hydrogen bond self-assembly strategy provides a strong P/N synergistic effect for MCA. Combined with the in-situ dispersion strategy, adding only 9 wt% PZS@MCA can achieve the UL-94 V-0 rating with a total smoke production (TSP) values of 21.1 m2. Besides, EP/PZS@MCA-I maintains superior mechanical properties due to larger aspect ratio, abundant terminal functional groups and better dispersion of PZS@MCA.在工业界和学术界,设计具有优异抑烟性能、机械性能和简单制造工艺的阻燃环氧树脂(EP)一直是一项非常具有挑战性的工作。在此,我们合成了一种富含氨基的聚磷腈微球(PZS),通过氢键自组装和原位分散策略调节三聚氰胺氰尿酸盐(MCA)的合成,用于阻燃环氧树脂(EP)。原位分散策略利用 EP 预聚物的粘度,有效缓解了 PZS@MCA 组装单元的团聚。氢键自组装策略为 MCA 提供了强大的 P/N 协同效应。结合原位分散策略,只需添加 9 wt% 的 PZS@MCA 即可达到 UL-94 V-0 等级,总产烟量(TSP)值为 21.1 m2。此外,EP/PZS@MCA-I 还具有更大的长径比、丰富的末端官能团和更好的 PZS@MCA 分散性,因此能保持优异的机械性能。Facile engineering strategy to control polymer chain structure for enhanced dispersion, electrical and sensing properties of nanocompositesNa Kim Mi, Lee Hyeseong, Cho Jaehyun, Jun Oh Myung, Hun Kim Seong, Jang Ji-un, Yun Kim Seongdoi:10.1016/j.compositesa.2023.107827 控制聚合物链结构以增强纳米复合材料的分散、电气和传感性能的简便工程策略Preventing the aggregation of nanofillers and inducing uniform filler dispersion are key parameters for improving the electrical conductivity and sensing sensitivity of nanocomposites. Although the viscosity and flow index which are determined by the polymer chain structure can significantly influence the nanofiller dispersion, few systematic structural and physical analyses have been reported. In this study, a facile engineering strategy to control the polymer chain structure was designed and applied using quad-screw extrusion (QSE) capable of transferring high shear stresses. According to the increase in rotation speed of the QSE, low molecular weight polymer chains with relatively uniform chain length were prepared, enabling the fabrication of a nanocomposite with uniform dispersion. Compared to the controls, when the optimized matrix (2000 rpm) was applied to the nanocomposite with 1wt% multi-walled carbon nanotubes, the improved strain sensor sensitivity of 798.3% were achieved owing to the improved filler dispersion and electrical conductivity.防止纳米填料聚集和诱导填料均匀分散是提高纳米复合材料导电性和传感灵敏度的关键参数。虽然由聚合物链结构决定的粘度和流动指数会显著影响纳米填料的分散,但系统的结构和物理分析却鲜有报道。在本研究中,我们设计了一种控制聚合物链结构的简便工程策略,并将其应用于能够传递高剪切应力的四螺杆挤出(QSE)。根据 QSE 旋转速度的增加,制备出链长相对均匀的低分子量聚合物链,从而制造出分散均匀的纳米复合材料。与对照组相比,当将优化基质(2000 rpm)应用于含有 1wt% 多壁碳纳米管的纳米复合材料时,由于填料分散性和导电性得到改善,应变传感器灵敏度提高了 798.3%。Fabrication and Performance of Ultrathin and Adhesive Composite Film with High Out-of-Plane Thermal Conductivity Using 3D Printing and Microwire-cutting AssistanceLv Ruicong, Ren Liucheng, Kang Lei, Niu Resouces Hongyu, Bashir Akbar, Bai Shulindoi:10.1016/j.compositesa.2023.107828利用三维打印和微线切割技术制造具有高平面外导热性的超薄粘合复合膜及其性能This study presents the development of a highly thermally conductive adhesive film based on an epoxy matrix filled with high-oriented graphite films (GFs). The film was fabricated using a 3D-printed framework to fix aligned GFs in a parallel configuration, followed by the infusion of liquid epoxy. A diamond microwire cutting technique was employed to obtain a 0.4 mm thick epoxy composite film. The resulting film exhibits an impressive apparent out-of-plane thermal conductivity of 20 Wm-1K-1 and a notable tensile shear strength of 5.91 MPa, with a GF volume fraction of 75%. Finite element simulations were employed to accurately predict the TC, which is found to be in excellent agreement with experimental results. The unprecedented combination of high out-of-plane TC and adhesive performance in such a thin adhesive film opens up opportunities for its utilization in various thermal management applications, including electronic packaging, LED systems, etc.本研究介绍了一种基于环氧树脂基体的高导热粘合薄膜的开发 情况,该基体中填充了高取向石墨薄膜(GFs)。薄膜的制作采用了三维打印框架,将排列整齐的石墨膜固定在平行配置上,然后注入液态环氧树脂。采用金刚石微线切割技术获得了 0.4 毫米厚的环氧树脂复合薄膜。在 GF 体积分数为 75% 的情况下,生成的薄膜显示出 20 Wm-1K-1 的显著平面外热导率和 5.91 MPa 的显著拉伸剪切强度。我们采用有限元模拟来精确预测薄膜的热导率,结果发现它与实验结果非常吻合。如此薄的粘合剂薄膜前所未有地兼具高平面外热导率和粘合性能,为其在电子封装、LED 系统等各种热管理应用中的应用带来了机遇。Composites Part B: EngineeringDesign, analysis and testing of thermoplastic welded stiffened panels to investigate skin-stringer separation in post-bucklingvan Dooren Kevin, Bisagni Chiaradoi:10.1016/j.compositesb.2023.111033热塑性焊接加劲板的设计、分析和测试,以研究屈曲后的表皮-弦杆分离情况Thermoplastic composite three-stringer panels with omega stiffeners and conduction welded joints are designed, analysed and tested until final failure to investigate the performance of the welded joint in post-buckling. The three-stringer panels are designed to be structurally representative of the fuselage demonstrator of the Clean Sky 2 project STUNNING. A simplified model of the fuselage keel section is analysed by finite element analysis, using the virtual crack closure technique to model skin-stringer separation of the welded joint. The post-buckling and skin-stringer separation behaviour of the fuselage section is then adopted as the reference for the design of the three-stringer panels. Two panels are then tested. The test setup utilises digital image correlation to measure the deformation of the panels, and a high-speed camera to capture the final failure mode. The panels failed in post-buckling due to the separation of the middle stringer, with unstable separation growth followed by separation of the outer stringers and then stringer fracture. The numerical analysis of the panels, with geometrical imperfections included, is able to predict the structural behaviour accurately, with only minor differences in buckling shape and separation behaviour.对带有欧米茄加强筋和传导焊接接头的热塑性复合材料三弦板进行了设计、分析和测试,直至最终失效,以研究焊接接头在后弯曲中的性能。三弦板的设计在结构上代表了 "洁净天空 2 号 "项目 "STUNNING "的机身验证机。对机身龙骨部分的简化模型进行了有限元分析,使用虚拟裂缝闭合技术对焊接接头的蒙皮-弦杆分离进行建模。然后将机身部分的后屈曲和蒙皮-弦杆分离行为作为三弦杆面板设计的参考。然后对两块面板进行测试。测试装置利用数字图像相关技术测量面板的变形,并利用高速摄像机捕捉最终的失效模式。面板在后屈曲过程中因中间弦杆分离而失效,分离增长不稳定,随后外弦杆分离,然后弦杆断裂。对包含几何缺陷的面板进行的数值分析能够准确预测结构行为,仅在屈曲形状和分离行为方面存在细微差别。Lightweight, strong, and thermally insulating polybenzoxazine aerogel thermal protection composites for antioxidant ablation long to 1800 sXiao Yunyun, Liu Saihui, Zhou Jinlong, Zhang Sizhao, Li Zhenquan, Xiong Shixian, Li Liangjun, Feng Jiandoi:10.1016/j.compositesb.2023.111045重量轻、强度高、隔热性能好的聚苯并恶嗪气凝胶热保护复合材料,可用于长达 1800 秒的抗氧化烧蚀The lightweight ablation materials that have been successfully applied in thermal protection systems (TPS) are the focus of attention owing to the urgent demand for aerospace vehicles to have efficient thermal insulation materials with lightweight, long-term antioxidant, and micro-ablation. However, improving the antioxidant ablation properties in a long-term aerobic atmosphere is still a significant challenge. Herein, a novel strategy to fabricate needle quartz fiber (NQF) reinforced SiO2 aerogel interpenetrating polybenzoxazine (PBO) aerogel thermal protection composites (NQF/SiO2–PBOs) with a binary network structure is proposed. The as-prepared NQF/SiO2–PBOs perfectly inherited their porous nanostructure and captivating properties, including lightweight (0.53 g/cm3), high mechanical strengths, and low thermal conductivity of 0.048 W/(m·K) at 25 °C and 0.079 W/(m·K) at 1100 °C. Moreover, the NQF/SiO2–PBOs exhibited outstanding high-temperature thermal insulation and long-time antioxidant ablation with low linear and mass ablation rates. The cold surface temperature peaked at approximately 307.2 °C within 1800 s when the hot surface temperature exceeded 1100 °C. The ablation/thermal insulation mechanism was also discussed through the analysis of the microstructure, chemical structure, and crystal structure. This research provides a meaningful reference for the development and exploitation of new advanced lightweight, long-term antioxidant, and micro-ablative thermal protective materials.由于航空航天飞行器对轻质、长期抗氧化和微烧蚀的高效隔热材料的迫切需求,已成功应用于热保护系统(TPS)的轻质烧蚀材料成为关注的焦点。然而,在长期有氧环境中提高抗氧化消融性能仍是一项重大挑战。本文提出了一种新的策略来制造具有二元网络结构的针状石英纤维(NQF)增强二氧化硅气凝胶互穿聚苯并恶嗪(PBO)气凝胶热防护复合材料(NQF/SiO2-PBOs)。制备的NQF/SiO2-PBOs完美地继承了其多孔纳米结构和迷人的性能,包括轻质(0.53 g/cm3)、高机械强度和低导热率(25 °C时为0.048 W/(m-K),1100 °C时为0.079 W/(m-K))。此外,NQF/SiO2-PBOs 还具有出色的高温隔热性能和长时间抗氧化烧蚀性能,且线性烧蚀率和质量烧蚀率较低。当热表面温度超过 1100 ℃ 时,冷表面温度在 1800 秒内达到峰值,约为 307.2 ℃。通过对微观结构、化学结构和晶体结构的分析,还讨论了烧蚀/隔热机制。这项研究为开发和利用新型先进的轻质、长效抗氧化和微烧蚀热防护材料提供了有意义的参考。Fabrication of photocatalytic PAN nanofiber membrane loading with TiO2@RGO by electro-spinning & electro-sprayingNiu Linyan, Zhang Baichuan, Sun Jun, Wang Jianjun, Qin Chuanxiang, Dai Lixingdoi:10.1016/j.compositesb.2023.111046 通过电纺丝和电喷雾法制备负载 TiO2@RGO 的光催化 PAN 纳米纤维膜The new fibrous photocatalytic nanofiber membrane with both good photodegradation performance and mechanical property was developed. Here, TiO2@RGO (TR) which could disperse in PAN solution stably was prepared by solvothermal method with the help of acetic acid. Then the new photocatalytic PAN nanofiber membrane SS7.5-2.3TR(A) was fabricated for the first time by electro-spinning & electro-spraying, where TR ruled as photocatalysts. Benefited from its novel triple structure, SS7.5-2.3TR(A) had the best toughness when compared with S-0 (electro-spun dual-network structural membrane) and SS7.5 (control membrane without TR in electro-spraying solution). Moreover, the morphology and mechanical property of membrane was similar to that of original SS7.5-2.3TR when it was used to photodegrade methyl orange solution five times later. Meanwhile, SS7.5-2.3TR also had significant photocatalytic performance when applied to the degradation of other three dyes (rhodamine B, methylene blue and oil red) and silk dyeing wastewater, which indicated its potential in dyeing wastewater treatment.新型纤维状光催化纳米纤维膜兼具良好的光降解性能和机械性能。该研究以醋酸为溶剂,采用溶热法制备了可稳定分散于 PAN 溶液中的 TiO2@RGO(TR),并在此基础上制备了新型光催化 PAN 纳米纤维膜 SS7.5-2.3TR。然后,通过电纺丝和电喷雾法首次制备了新型光催化 PAN 纳米纤维膜 SS7.5-2.3TR(A),其中 TR 作为光催化剂。与 S-0(电纺双网络结构膜)和 SS7.5(电喷雾溶液中不含 TR 的对照膜)相比,SS7.5-2.3TR(A)得益于其新颖的三层结构,具有最佳的韧性。此外,用 SS7.5-2.3TR 光降解甲基橙溶液 5 次后,膜的形貌和机械性能与原 SS7.5-2.3TR 相似。同时,SS7.5-2.3TR 在降解其他三种染料(罗丹明 B、亚甲基蓝和油红)和丝绸染色废水时也具有显著的光催化性能,这表明其在染色废水处理方面具有潜力。Composites Science and TechnologyUltra-sensitive flexible pressure sensor with hierarchical structural laser-induced carbon nanosheets/carbon nanotubes composite filmGuo Xuanqi, Li Yunfan, Zeng Ziran, Zhao Yilin, Lei Xiao, Wang Yaoyu, Guo Dingyi, Liu Fengdoi:10.1016/j.compscitech.2023.110290 采用分层结构激光诱导碳纳米片/碳纳米管复合膜的超灵敏柔性压力传感器Recently, laser induced carbon nanosheets (LICs) based flexible pressure sensors have received widespread attention. Introducing hierarchical microstructure is an effective method to improve the sensitivity of pressure sensors. However, implementing hierarchical microstructure on LICs film through a simple and low damage process remains a challenge. Herein, taking advantage of the reshaping characteristics of low melting point thermoplastic substrate styrene-isoprene-styrene (SIS) under laser thermal effects, a simple and one-step laser thermoforming process is used to spontaneously form surface microstructure on the LICs film during the formation of LICs. Therefore, a hierarchical structure composed of porous structure and surface microstructure was achieved on the LICs film through the one-step process. Furthermore, a hybrid strategy combining hierarchical microstructure with carbon nanotubes (CNTs)/LICs composite was proposed to improve the sensitivity of LICs based pressure sensor. Benefiting from the hierarchical structure of LICs and the composite conductive network constructed by CNTs and LICs, the LICs/CNTs@SIS sensor exhibits ultrahigh sensitivity of 1089 kPa−1 in 0–5 kPa and ultrahigh gauge factor of 1493 within the strain rate range of 20%–28%. Meanwhile, the sensor has good stability (>1400 cycles), response and recovery times of 23.8 ms and 25.9 ms, excellent reversibility, and 1220% elongation at break. Besides, the application of the sensor in physiological signal monitoring and pressure distribution detection indicates its great potential in flexible electronics.最近,基于激光诱导碳纳米片(LICs)的柔性压力传感器受到了广泛关注。引入分层微结构是提高压力传感器灵敏度的有效方法。然而,如何通过简单、低损伤的工艺在 LICs 薄膜上实现分层微结构仍是一项挑战。本文利用低熔点热塑性基材苯乙烯-异戊二烯-苯乙烯(SIS)在激光热效应下的重塑特性,采用简单的一步激光热成型工艺,在 LICs 薄膜形成过程中自发形成表面微结构。因此,一步法工艺在 LICs 薄膜上实现了由多孔结构和表面微结构组成的分层结构。此外,还提出了一种将分层微结构与碳纳米管(CNTs)/LICs 复合材料相结合的混合策略,以提高基于 LICs 的压力传感器的灵敏度。得益于 LICs 的分层结构以及 CNT 与 LICs 构建的复合导电网络,LICs/CNTs@SIS 传感器在 0-5 kPa 范围内表现出 1089 kPa-1 的超高灵敏度,在 20%-28% 应变率范围内表现出 1493 的超高表征因子。同时,该传感器具有良好的稳定性(大于 1400 次循环)、23.8 毫秒和 25.9 毫秒的响应和恢复时间、出色的可逆性以及 1220% 的断裂伸长率。此外,该传感器在生理信号监测和压力分布检测方面的应用表明,它在柔性电子领域具有巨大潜力。来源:复合材料力学仿真Composites FEM

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