今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Electrical energy and overpressure characterization of aeronautical fasteners submitted to a lightning current waveform
Rafael Sousa Martins, Amélie Jarnac, Clément Zaepffel, Philippe Lalande
doi:10.1016/j.compstruct.2024.118700
雷电电流波形下航空紧固件的电能和超压特性
Understanding and controlling sparking in fasteners and jointed structures is crucial for flight safety, particularly in fuel tanks. This study investigates the relationship between dissipated electrical energy and pressure buildup within fastener cavities during lightning strikes. Experiments were performed on fasteners installed in aluminum and Carbon Fiber Reinforced Polymer (CFRP) samples, with lightning current waveforms ranging from 1 kA to 10 kA. A sensitivity analysis evaluated the influence of key parameters, such as current peak, clearance fit, sample material, polarity, and fastener coating on pressure rise and energy dissipation. Electrical energy up to 80J and pressure levels reaching 600 bar– unprecedented compared to prior studies – were observed. The pressure-energy relationship showed an approximately linear trend, while pressure exhibited a non-linear dependence on clearance fit. Fastener coating and sample material were found to significantly influence the results, with pressure variations reaching up to a factor of 10 in some cases.
了解和控制紧固件和连接结构中的火花对飞行安全至关重要,特别是在油箱中。本研究探讨了雷击时紧固件腔内耗散的电能和压力之间的关系。对安装在铝和碳纤维增强聚合物(CFRP)样品中的紧固件进行了实验,雷电电流波形范围为1 kA至10 kA。灵敏度分析评估了关键参数,如电流峰值、间隙配合、样品材料、极性和紧固件涂层对压力上升和能量耗散的影响。观察到高达80J的电能和达到600 bar的压力水平-与先前的研究相比是前所未有的。压力-能量关系呈现近似线性趋势,而压力与间隙拟合呈非线性关系。发现紧固件涂层和样品材料对结果有显著影响,在某些情况下压力变化可达10倍。
Inverse design method of deployable cylindrical composite shells for solar sail structure
Zheng Zhang, Diyong Huang, Baisong Pan, Huping Zhou, Jingya Ma, Min Sun, Shouzhi Ren, Guang Zhang
doi:10.1016/j.compstruct.2024.118698
太阳帆结构可展开圆柱复合壳的反设计方法
The deployable cylindrical composite shell (DCCS) applied in the solar sail structure requires suitable geometric parameters to have high storage capacity and large sunlight area. However, it is difficult to obtain the suitable geometric parameters of DCCS. An inverse design method combining the advantages of radial basis function artificial neural network (RBFANN) and multi-island genetic algorithm (MIGA) is proposed to obtain the geometric parameters of DCCS in this paper. RBFANN has the ability of self-learning and nonlinear problem solving, MIGA has the ability of global optimization. The specimens of DCCS were manufactured based on the obtained geometric parameters. The coiling radius, driving characteristics of specimens were studied by experiment and finite element simulation, and the numerical results are in good agreement with the experimental results, which verify the effectiveness of the inverse design method. The inverse design method proposed in this paper can effectively obtain the geometric parameters of DCCS, which also can guide the design of solar sail structure.
应用于太阳帆结构的可展开圆柱形复合材料壳体(DCCS)需要合适的几何参数来保证高存储容量和大的日照面积。然而,DCCS的几何参数很难确定。结合径向基函数人工神经网络(RBFANN)和多岛遗传算法(MIGA)的优点,提出了一种求解DCCS几何参数的反设计方法。RBFANN具有自学习能力和非线性问题求解能力,MIGA具有全局优化能力。根据得到的几何参数制作DCCS试件。通过实验和有限元模拟对试件的卷取半径、驱动特性进行了研究,数值结果与实验结果吻合较好,验证了反设计方法的有效性。本文提出的逆设计方法可以有效地获得DCCS的几何参数,也可以指导太阳帆结构的设计。
Finite element submodeling technique-based fatigue analysis and reliability modeling of wind turbine blade trailing edge
Zheng Liu, Jinlong Liang, Zhenfeng He, Xin Liu, Haodong Liu, Zhenjiang Shao
doi:10.1016/j.compstruct.2024.118699
基于有限元子建模技术的风力机叶片尾缘疲劳分析与可靠性建模
Wind turbine blades play a critical role in wind turbine systems, with the trailing edge bearing significant mechanical loads. During operational cycles, the adhesively bonded composite trailing edge may fracture, delaminate, or buckle, posing a safety risk for wind turbine systems. While finite element simulation is commonly used to evaluate blade fatigue performance due to the challenges associated with full-scale structural tests in terms of costs and time, current methodologies mainly focus on the overall fatigue characteristics of blades, neglecting specialized analyses. A finite element submodeling approach is presented here to address this research gap by analyzing wind turbine blade trailing edges for fatigue and reliability. Specifically, a finite element submodelingmethodis proposedtoanalyzelocal fatiguefailuresof wind turbine blades. This approach is validated through fatigue testing on conventional composite bonded specimens. Subsequently, failure analyses and life predictions are conducted on the trailing edges to investigate their fatigue behavior, followed by an exploration of the impact of submodeling techniques on the analysis results. Furthermore, considering material and dimensional uncertainties, a fatigue reliability model for trailing edges is developed. The results demonstrate that this approach effectively overcomes the limitations of overall blade finite element analysis by enabling localized fatigue analysis of the trailing edge, providing valuable insights for improving wind turbine blade design optimization.
风力涡轮机叶片在风力涡轮机系统中起着至关重要的作用,其后缘承受着巨大的机械载荷。在运行周期中,粘接复合材料后缘可能会断裂、分层或弯曲,对风力涡轮机系统构成安全风险。由于在成本和时间方面与全尺寸结构测试相关的挑战,有限元模拟通常用于评估叶片的疲劳性能,但目前的方法主要集中在叶片的整体疲劳特性上,而忽略了专业分析。本文提出了一种有限元子建模方法,通过分析风力机叶片尾缘的疲劳和可靠性来解决这一研究空白。具体地说,提出了一种分析风力发电机叶片局部疲劳失效的有限元子建模方法。通过常规复合材料粘结试件的疲劳试验验证了该方法的有效性。随后,对尾缘进行失效分析和寿命预测,以研究其疲劳行为,然后探索子建模技术对分析结果的影响。此外,考虑材料和尺寸的不确定性,建立了尾缘的疲劳可靠性模型。结果表明,该方法有效克服了整体叶片有限元分析的局限性,实现了尾缘局部疲劳分析,为改进风力机叶片设计优化提供了有价值的见解。
Effects of selective distribution of poly(methyl methacrylate)-grafted graphene oxide on the phase behavior and conductivity of poly(methyl methacrylate)/poly(vinyl acetate) blends
Xiaofeng Yu, Zheng Xu, Yaobin Lu, Li Yang, Shihao Sun, Miao Du, Min Zuo, Qiang Zheng
doi:10.1016/j.compositesa.2024.108563
聚甲基丙烯酸甲酯接枝氧化石墨烯的选择性分布对聚甲基丙烯酸甲酯/聚醋酸乙烯共混物相行为和电导率的影响
The effect of selective distribution of two kinds of poly (methyl methacrylate)-grafted graphene oxide (PMMA-g-GO) nanosheets (NSs) on the phase behavior and conductivity of PMMA/poly (vinyl acetate) (PVAc) blends is investigated. The grafting density and length of two modified GO NSs are different, resulting in their thermodynamic equilibrium location in the blend matrix, but their initial locations are both in the PVAc-rich phase with low viscosity. The PMMA-g-GO(6 k) NSs with the sparse mushroom-like grafted PMMA chains gradually migrate to the interface of blend matrix and aggregate to form the conductive network, resulting in the suppression of domain coarsening and long-term maintenance of co-continuous morphology. The grafted chains on the surface of PMMA-g-GO(58 k) NSs exhibit the screened wet brush and the PMMA matrix chains can penetrate with the grafted chains, resulting in the location in the PMMA-rich phase. Two modified GO NSs filled PMMA/PVAc nanocomposites can occur the conductive percolation and such activation energies are higher than those of flow for PMMA and PVAc, indicating that the interactions between modified GO and polymer components may restrict the aggregation of conductive modified GO NSs at the interface or in the PMMA-rich phase.
研究了两种聚甲基丙烯酸甲酯接枝氧化石墨烯(PMMA-g- go)纳米片(NSs)的选择性分布对PMMA/聚醋酸乙烯酯(PVAc)共混物相行为和电导率的影响。两种改性的氧化石墨烯纳米粒子的接枝密度和长度不同,导致它们在共混基体中的热力学平衡位置不同,但它们的初始位置都在低粘度的富pvac相中。具有稀疏蘑菇状接枝PMMA链的PMMA-g- go(6 k) NSs逐渐迁移到共混基体和聚团界面形成导电网络,从而抑制畴粗化,长期维持共连续形态。PMMA-g- go(58 k) NSs表面的接枝链呈现出筛选过的湿刷状,PMMA基体链可以穿透接枝链,从而定位在富PMMA相中。填充PMMA/PVAc纳米复合材料的两种改性氧化石墨烯纳米粒子均可发生导电渗透,且其活化能均高于PMMA和PVAc的流动活化能,说明改性氧化石墨烯与聚合物组分之间的相互作用可能限制了导电改性氧化石墨烯纳米粒子在界面处或富PMMA相的聚集。
Interface engineering of MXene towards highly fire-safe epoxy resin with enhanced thermal conductivity
Chuan Liu, Shu-Gen Wu, Jie-Hao He, Xin Li, Zhen Qin, Dong-Yi He, Yan-Fang Xiao, Yi Wang, Yu-Zhong Wang, Li Chen
doi:10.1016/j.compositesa.2024.108585
MXene面向高防火性增强导热环氧树脂的界面工程
The integration of superior flame retardancy and enhanced thermal conductivity of epoxy resins (EP) is highly desirable for practical applications. Herein, novel organophosphorus-decorated MXene hybrid flame retardant (PMXene) was prepared by the interface engineering between melamine diphenylphosphinate (MDP) and two-dimensional titanium carbide (MXene). With the loading of 6.0 wt% PMXene, the EP/6.0PMXene material achieved a V-0 rating during the UL 94 testing besides the high limiting oxygen index (35.2 %). Cone calorimetric results revealed that the peak of heat release, peak of smoke release rate and smoke factor values of EP/6.0PMXene were reduced by 36.6 %, 27.6 % and 48.7 %, respectively, in comparison with those of pristine EP. Besides, the PMXene hybrid enhanced the thermal conductivity of EP to 0.38 W/m·K, a 52.6 % improvement over pristine EP. Thus, this work provides a novel strategy for fabricating thermosetting materials with high fire-safety and enhanced thermal conductivity.
环氧树脂(EP)优异的阻燃性和增强的导热性在实际应用中是非常理想的。通过三聚氰胺二苯膦酸盐(MDP)与二维碳化钛(MXene)的界面工程,制备了新型有机磷修饰MXene杂化阻燃剂(PMXene)。在6.0 wt% PMXene的负载下,EP/6.0PMXene材料在UL 94测试中达到了V-0等级,并且具有高极限氧指数(35.2 %)。锥形量热结果表明,EP/6.0PMXene的放热峰、排烟率峰和排烟因子值分别比原始EP降低36.6 %、27.6 %和48.7 %。此外,PMXene混合材料将EP的导热系数提高到0.38 W/m·K,比原始EP提高了52.6% %。因此,这项工作为制造具有高防火安全性和增强导热性的热固性材料提供了一种新的策略。
Designing High-Performance Green Tire Treads by Reinforcing the Styrene-Butadiene Rubber/Silica Interface with Chain Difunctionalization
Yihui Xu, Yudong Liu, Yangyang Gao, Ling Liu, Liqun Zhang
doi:10.1016/j.compositesb.2024.111887
利用链双官能化强化丁苯橡胶/二氧化硅界面设计高性能绿色轮胎胎面
For green tires, monofunctionalization of rubber has been extensively studied to enhance the interface between rubber and silica. However, the effect of chain difunctionalization has not been reported. In this work, the difunctionalized styrene-butadiene rubber (SBR-DF) was first prepared by grafting small molecules with different functional groups (3-mercaptopropionic acid, 3-mercaptoethanol, and mercaptosilane) to end-group functionalized SBR through thiol-ene click reaction. Then, the molecular dynamics simulation was adopted to calculate the interaction energy between SBR-DF and silica. The results showed that the chain difunctionalization can significantly increase the interfacial interaction energy between them, which was further validated by using RPA and SEM. Moreover, the introduced siloxane groups in the rubber chain can greatly improve the interfacial interaction energy by more than 20%, which can achieve the uniform dispersion of silica. As a result, the SBR-DF/Silica composites showed the excellent dynamic mechanical properties, such as high wet slip resistance (21% increase), low rolling resistance (23% reduction) and high wear resistance (20% reduction). As a result, the energy consumption of SBR-DF/Silica composites was reduced, which endowed green tires with excellent safety. In summary, this work provides a new and effective strategy for manufacturing the energy-saving, green and safe design of “green tires”.
对于绿色轮胎,人们广泛研究了橡胶的单功能化,以增强橡胶与二氧化硅之间的界面。然而,链双官能化的影响尚未见报道。本文首先通过巯基咔嗒反应将具有不同官能团的小分子(3-巯基丙酸、3-巯基乙醇和巯基硅烷)接枝到端基官能团化的SBR上,制备了双官能团化丁苯橡胶(SBR- df)。然后,采用分子动力学模拟方法计算SBR-DF与二氧化硅的相互作用能。结果表明,链的双官能化可以显著提高它们之间的界面相互作用能,并通过RPA和SEM进一步验证了这一点。此外,在橡胶链中引入硅氧烷基团,可大大提高界面相互作用能20%以上,可实现二氧化硅的均匀分散。结果表明,SBR-DF/Silica复合材料具有优异的动态力学性能,如高湿滑性能(提高21%)、低滚动性能(降低23%)和高耐磨性(降低20%)。因此,降低了SBR-DF/Silica复合材料的能耗,使绿色轮胎具有优异的安全性。本研究为实现节能、绿色、安全的“绿色轮胎”设计提供了新的有效策略。
Dual covalent bond induced high thermally conductive polyimide composite films based on CNT@CN complex filler
Fan Wang, Xiaodi Dong, Guangyi Liu, Jing-Hui Gao, Xu Wang, Jun-Wei Zha
doi:10.1016/j.compscitech.2024.110963
基于CNT@CN复合填料的双共价键诱导高导热聚酰亚胺复合薄膜
Polyimide (PI) possesses excellent high-temperature resistance, insulation properties, and mechanical properties, making it widely used as a flexible printed circuit board substrate and high-temperature electrical insulation material. However, the irregular arrangement of PI molecules results in a relatively low thermal conductivity. This work utilizes the active groups on the surface of carboxylated multi-walled carbon nanotubes (MWCNTs) and carbon nitride nanosheets (CNNS) to obtain CNTs@CN complex fillers containing covalent bonds. The thermal conductivity of CNTs@CN/PI with double covalent bonds can be up to 6.63 W∙m-1∙K-1. The covalent bonds between fillers and fillers as well as between fillers and the matrix provide efficient and continuous pathways for phonon transmission. Additionally, finite element analysis further reveals the heat transfer mechanism of the CNTs@CN/PI composite film. Therefore, this will provide a feasible solution to enhance the thermal conductivity of PI, making it more promising for applications in electronic devices.
聚酰亚胺(PI)具有优异的耐高温性能、绝缘性能和机械性能,广泛用作柔性印刷电路板基板和高温电绝缘材料。然而,PI分子的不规则排列导致其导热系数相对较低。本研究利用羧化多壁碳纳米管(MWCNTs)和氮化碳纳米片(CNNS)表面的活性基团获得含有共价键的CNTs@CN复合填料。具有双共价键的CNTs@CN/PI的导热系数可达6.63 W∙m-1∙K-1。填料与填料之间以及填料与基体之间的共价键为声子传输提供了高效、连续的途径。此外,通过有限元分析进一步揭示了CNTs@CN/PI复合膜的传热机理。因此,这将为提高PI的导热性提供一种可行的解决方案,使其在电子器件中的应用更具前景。