今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 5 篇
Structural design and experimental study of CFRP bamboo rat tooth bionic drill bit
Fei Su, Ke Chen, Xing Liu, Ke Zhang, Xun Ding
doi:10.1016/j.compstruct.2024.117950
CFRP 竹鼠齿仿生钻头的结构设计与实验研究
The holes are very easy to appear delamination and burr during CFRP drilling. The tool geometry has a great impact on the hole making. In this paper, according to the principle of bionics and structural features, a novel bionic drill bit was designed. The mathematical model of the lower incisor teeth occlusal movement was established. The cutting mechanism of the bamboo rat lower incisor on PW-CFRP material was studied. It was found that the curvature of the contour curves of the front cutter faces were constantly changing, which was conducive to the removal of chips. The curvature change of the contour curve of the rear cutter surface is small and the curve is relatively smooth, which is conducive to reducing friction. The mathematical modeling analysis was carried out on the feeding process of bamboo rats, and the mathematical relationship between the bite radius R and the cutting angle θ was obtained. The optimal cutting angle θ=10° and the corresponding biting radius R=40mm were obtained by finite element simulation. The surface cutting quality of bamboo rat's lower incisors is better than that of ordinary cutting tools. The novel bionic tool can effectively reduce the burr and delamination of the exit layer.
在 CFRP 钻孔过程中,孔很容易出现分层和毛刺。刀具的几何形状对钻孔有很大影响。本文根据仿生学原理和结构特点,设计了一种新型仿生钻头。建立了下门牙咬合运动的数学模型。研究了竹鼠下门齿在 PW-CFRP 材料上的切割机理。研究发现,前刀面轮廓曲线的曲率不断变化,有利于切屑的清除。后刀面轮廓曲线的曲率变化较小,曲线相对平滑,有利于减少摩擦。对竹鼠的进料过程进行了数学建模分析,得到了咬合半径 R 与切削角 θ 之间的数学关系。通过有限元模拟得到了最佳切削角θ=10°和相应的咬合半径R=40mm。竹鼠下门齿的表面切削质量优于普通刀具。新型仿生刀具能有效减少毛刺和出口层的分层。
A theoretical study on the temperature-dependent yield strength of in-situ particle and whisker hybrid-reinforced metal matrix composites
Ruozhen Zhang, Pan Dong, Xuyao Zhang, Ziyuan Zhao, Weiguo Li, Tianbao Cheng, Xianhe Zhang
doi:10.1016/j.compstruct.2024.117962
原位颗粒和晶须混合增强金属基复合材料屈服强度随温度变化的理论研究
The hybrid effect observed in hybrid-reinforced composites presents a promising opportunity to further enhance the mechanical properties of composites. In this study, a theoretical model is established to determine the yield strength of in-situ particle and whisker hybrid-reinforced metal matrix composites by considering the mechanisms of stress transfer strengthening and grain boundary strengthening. And the hybrid effect is well characterized. The model is then extended to incorporate temperature dependence, considering changes in key parameters as temperature varies. With only one readily available experimental reference point, yield strength at different temperatures can be conveniently predicted. Satisfactory agreements are achieved between model predictions and experimental data. Moreover, quantitative analyses are performed to examine the hybrid effect at various temperatures and reinforcement volume fractions. The results show that the hybrid effect increases significantly with the increasing reinforcement volume fraction, but as the temperature increases, the hybrid effect decreases in proportion to the matrix yield strength.
在混合增强复合材料中观察到的混合效应为进一步提高复合材料的机械性能提供了一个大有可为的机会。本研究建立了一个理论模型,通过考虑应力传递强化和晶界强化机制来确定原位颗粒和晶须混合强化金属基复合材料的屈服强度。并很好地描述了混合效应。然后对模型进行了扩展,纳入了温度依赖性,考虑了温度变化时关键参数的变化。只需一个现成的实验参考点,就能方便地预测不同温度下的屈服强度。模型预测与实验数据之间达到了令人满意的一致。此外,还进行了定量分析,以研究不同温度和钢筋体积分数下的混合效应。结果表明,混合效应随着钢筋体积分数的增加而显著增加,但随着温度的升高,混合效应与基体屈服强度成比例地减小。
Fatigue crack growth characterization of composite-to-steel bonded interface using ENF and 4ENF tests
Weikang Feng, Marcio Moreira Arouche, Marko Pavlovic
doi:10.1016/j.compstruct.2024.117963
利用 ENF 和 4ENF 试验鉴定复合材料与钢粘接界面的疲劳裂纹生长特征
In this paper, mode II fatigue crack growth properties of the composite-to-steel interface are characterised through different test configurations, namely ENF and 4ENF tests. Different loading types including force control and displacement control methods are compared. An innovative shear strain based method is proposed for monitoring the mode II crack growth at the bi-material interface through Digital Image Correlation (DIC). A 3D finite element model with Virtual Crack Closure Technique (VCCT) is built and used for obtaining the strain energy release rate (SERR) to investigate the effect of geometrical nonlinearity, friction at the interface and steel yielding, as well as to verify the mode mixity. The results show that the standard 3-point bending ENF specimen can be unstable under force control and sweeps narrow SERR range by a single test under displacement control. The 4-point bending 4ENF test shows stable crack propagation and clear SERR developing trend. More pronounced geometrical nonlinearity and friction effect exist for 4ENF test which can be considered in interpreting the Paris curves by a nonlinear finite element model.
本文通过不同的试验配置,即 ENF 和 4ENF 试验,对复合材料与钢材界面的模式 II 疲劳裂纹生长特性进行了表征。比较了不同的加载类型,包括力控制和位移控制方法。提出了一种基于剪切应变的创新方法,通过数字图像相关性(DIC)监测双材料界面的模式 II 裂纹生长。利用虚拟裂缝闭合技术(VCCT)建立了三维有限元模型,并利用该模型获得应变能释放率(SERR),以研究几何非线性、界面摩擦和钢屈服的影响,并验证模式混合性。结果表明,标准的三点弯曲 ENF 试样在力控制下可能不稳定,在位移控制下通过一次试验就能扫过较窄的 SERR 范围。4 点弯曲 4ENF 试验显示出稳定的裂纹扩展和明显的 SERR 发展趋势。4ENF 试验存在更明显的几何非线性和摩擦效应,可通过非线性有限元模型解释巴黎曲线。
Vibration suppression of a meta-structure with hybridization of Kresling origami and waterbomb-based origami
Haizhou Shi, Kai Zhang, Xiangbing Liu, Hong Liu, Haijun Peng, Zichen Deng
doi:10.1016/j.compstruct.2024.117964
克瑞斯林折纸与水弹折纸杂交的元结构振动抑制技术
In recent years, the unfolding capability and vibration-isolation properties of spacecraft have received increasing attention. Several studies have achieved deployability through origami structures and low-frequency broadband vibration isolation using origami-inspired meta-structures(OIMs). However, traditional origami prototypes do not fully satisfy aerospace engineering requirements. In this study, a new origami-inspired meta-structure with low-frequency broadband vibration-isolation performance was proposed by combining the geometric characteristics of Kresling origami and waterbomb-based origami. The bandgap distribution and transmission rate of the OIMs were investigated through numerical simulations and a transient displacement study to evaluate the vibration-isolation performance of the OIMs. Modulation of the band structures by changing the geometric parameters was also examined. Experimental tests were conducted to demonstrate and validate the vibration-isolation properties of the proposed meta-structure. The transmission rate and bandgap results were in good agreement. Wider bandgaps are achieved through the gradient design, and the truss design makes OIMs more suitable for engineering applications. This study presents a new origami-inspired meta-structure that provides a strategy for application of origami in aerospace engineering.
近年来,航天器的展开能力和隔振特性日益受到关注。一些研究通过折纸结构实现了可展开性,并利用折纸启发元结构(OIM)实现了低频宽带隔振。然而,传统的折纸原型并不能完全满足航空航天工程的要求。本研究结合克瑞斯林折纸和水弹折纸的几何特性,提出了一种具有低频宽带隔振性能的新型折纸启发元结构。通过数值模拟和瞬态位移研究,研究了 OIM 的带隙分布和传输速率,从而评估了 OIM 的隔振性能。此外,还研究了通过改变几何参数对带状结构进行调制的问题。为证明和验证拟议元结构的隔振性能,还进行了实验测试。传输率和带隙结果非常吻合。通过梯度设计实现了更宽的带隙,而桁架设计则使 OIM 更适合工程应用。本研究提出了一种新的受折纸启发的元结构,为折纸在航空航天工程中的应用提供了一种策略。
Enhancing Oxidation Resistance of Carbon Fibre Reinforced Phenolic Composites by ZrO2 Nanoparticles through Out-of-autoclave Vacuum Infusion
Zhao Sha, Wenmu Yang, Cheng Wang, Mohammad S. Islam, Guan Heng Yeoh, David L. Officer, Warren Canning, Jin Zhang, Chun H. Wang
doi:10.1016/j.compositesa.2024.108071
通过釜外真空灌注 ZrO2 纳米粒子增强碳纤维增强酚醛复合材料的抗氧化性
This study reports a vacuum-assisted resin infusion method for achieving low-porosity carbon fibre/phenolic resin composites utilizing a low-viscosity (∼281 cp) phenolic resin enhanced by ZrO2 nanoparticles. The experimental results reveal that this method can yield composites with a low porosity of 8.6±2.5 % and average pore size of 3.8±1.73 μm, while demonstrating mechanical properties that fulfill the requirements for high-temperature structural applications, such as the nozzle of rocket motor. Moreover, the resultant composites exhibit distinct advantages over composites produced using other out-of-autoclave and autoclave methods investigated in this study in terms of flexural strength and modulus after oxidation treatment. The vacuum infusion approach retains higher resin content in composites than the autoclave method, leading to increased residual modulus post-oxidation. Furthermore, incorporating ZrO2 nanoparticles in the phenolic matrix has shown a significant potential in achieving increased residual mass, flexural strength, and flexural modulus of composites, notably after exposure to short-duration oxidation.
本研究报告了一种真空辅助树脂灌注方法,该方法利用纳米 ZrO2 增强的低粘度(∼281 cp)酚醛树脂实现低孔隙率碳纤维/酚醛树脂复合材料。实验结果表明,该方法可获得孔隙率为 8.6±2.5 %、平均孔径为 3.8±1.73 μm 的低孔隙率复合材料,同时其力学性能也能满足火箭发动机喷嘴等高温结构应用的要求。此外,就氧化处理后的弯曲强度和模量而言,与本研究中采用其他釜外法和釜内法生产的复合材料相比,所生产的复合材料具有明显优势。与高压釜法相比,真空灌注法在复合材料中保留了更高的树脂含量,从而提高了氧化后的残余模量。此外,在酚醛基质中加入 ZrO2 纳米粒子在增加复合材料的残余质量、抗弯强度和抗弯模量方面具有显著的潜力,尤其是在暴露于短时间氧化后。
Bending behaviors and toughening mechanism of carbon fiber-aluminum honeycomb sandwich structures with stitched fiber belts
Haipeng Yu, Hongjie Chen, Bingyi Liang, Zhi Sun, Xu Guo
doi:10.1016/j.compositesa.2024.108072
带缝合纤维带的碳纤维-铝蜂窝夹层结构的弯曲行为和增韧机理
Bending behaviors of carbon fiber-aluminum honeycomb sandwich structures, that are toughened by stitched fiber belts, are experimentally and numerically studied. It is found that the stitched fiber belts show potential to enhance the peak load of sandwich specimens by up to 44.3%, and to arrest interfacial crack growth. Firstly, FE models are proposed for the sandwich structures with stitched carbon fiber belts, and the FE models are verified by three-point bending tests. Secondly, the effects of stitched carbon fiber belts on bending behaviors of sandwich beam are studied. Combining the experimental and numerical results, the main toughening mechanism of stitched fiber belts is observed. The stitched fiber belts increase bonding area between face-sheets and honeycomb core, on one hand, and therefore enhance the interfacial strength. On the other hand, the angled fiber belts inside the core are found to enhance load bearing capacity and transverse shear stiffness.
实验和数值研究了通过缝合纤维带增韧的碳纤维-铝蜂窝夹层结构的弯曲行为。研究发现,缝合纤维带有可能将夹层试样的峰值载荷提高 44.3%,并阻止界面裂纹生长。首先,针对带有缝合碳纤维带的夹层结构提出了有限元模型,并通过三点弯曲试验验证了有限元模型。其次,研究了缝合碳纤维带对夹层梁弯曲行为的影响。结合实验和数值结果,观察了缝合纤维带的主要增韧机理。一方面,缝合纤维带增加了面层与蜂窝芯之间的粘合面积,从而提高了界面强度。另一方面,芯材内部的斜纤维带可提高承载能力和横向剪切刚度。
Reformable and sustainable thermosetting carbon fiber composites from epoxy vitrimer
Philip R. Barnett, Justin A. Brackenridge, Abigail A. Advincula, Laine A. Taussig, Dhriti Nepal
doi:10.1016/j.compositesb.2024.111270
环氧玻璃聚合物的可改造和可持续热固性碳纤维复合材料
Vitrimers are an emerging class of thermosetting materials that undergo reversible dynamic covalent bonding to enable thermoplastic-like repair, joining, and recycling that is currently inaccessible to traditional thermosets. This work demonstrates the production of sustainable recycled carbon fiber/epoxy based vitrimer composites. A method of preparing B-staged vitrimer films enabled infusion of the vitrimer into a fibrous preform using scalable compression molding techniques to form fully cured, room temperature stored organosheets that were then consolidated into laminates. The influence of consolidation time on the thermo-mechanical properties of the resulting composites was evaluated using several techniques. Short beam strength testing was used to evaluate the interlaminar properties of the composites and assess the repairability of tested specimens. Additional processing time was shown to stiffen the materials at room temperature, due to thermo-oxidative crosslinking as opposed to further thermal cure. This led to an initial improvement in the short beam strength, but a reduction in energy absorption and ductility. The results of this work show that vitrimer composites may be effective in extending the life of in-service composite structures by mitigating or repairing damage.
玻璃聚合物是一类新兴的热固性材料,可进行可逆的动态共价键合,从而实现类似热塑性塑料的修复、连接和回收,这是传统热固性材料目前无法实现的。这项研究展示了可持续再生碳纤维/环氧树脂基玻璃纤维复合材料的生产过程。采用一种制备 B 级玻璃聚合物薄膜的方法,利用可扩展的压缩成型技术将玻璃聚合物注入纤维预型件中,形成完全固化、室温储存的有机片材,然后将其加固成层压板。我们使用多种技术评估了固化时间对所得复合材料热机械性能的影响。短梁强度测试用于评估复合材料的层间性能,并评估测试试样的可修复性。结果表明,由于热氧化交联而非进一步的热固化,额外的加工时间可使材料在室温下更加坚硬。这使得短梁强度得到初步改善,但能量吸收和延展性有所降低。这项工作的结果表明,通过减轻或修复损坏,玻璃纤维复合材料可以有效延长在用复合材料结构的寿命。
Metal-electronegativity-induced sulfur-vacancies and heterostructures of MnS1-x/ZnS-NC@C with dual-carbon decoration for high-performance sodium-ion storage
Hongyu Zhang, Zhenjiang Lu, Baolin Liu, Chun Yuan, Yali Cao
doi:10.1016/j.compositesb.2024.111267
金属负电荷诱导的硫空位和具有双碳装饰的 MnS1-x/ZnS-NC@C 异质结构用于高性能钠离子存储
Engineering unique architectural anode electrode materials with high storage capacity and stable structures to balance kinetics and capacity between anode and cathode possesses a huge challenge for sodium-ion hybrid capacitors (SIHCs). Herein, beginning with well-organized MnS nanoparticles, an elaborate design of introducing metal-organic frameworks and decorating with dual-carbon is presented to fabricate a desirable composite of bimetallic sulfide and carbon with carbon matrix/coating layers via electronegativity induction. The simultaneously formed rich sulfur-vacancies and heterostructures can significantly boost fast electron/ion diffusion kinetics and induce high reversible sodium-ion storage capacities. Moreover, dual-carbon decoration tactics allow the electrodes for superior electronic conductivity, guarantee a splendid structural stability and offer an avenue for electron transport, which enable MnS1-x/ZnS-NC@C (MSZNC) composites a steady capacity of 354 mAh g−1 for 1600 cycles at a high rate of 10 A g−1 in sodium-ion batteries (SIBs). Integrated with theoretical calculations, the systemic electrochemical kinetic analytical results reveal that the synergistic effect of heterostructures and sulfur-vacancies can furnish more reversible active sites and boost charge transfer, thereby accelerating reaction kinetics for an enhanced sodium-ion storage capability. As expected, the assembled SIHCs full cell based on MSZNC anode and AC cathode exhibits a high energy density of 116 W h kg−1 and a high power output of 95 W kg−1, a capacity retention of 87% at 2 A g−1 for 2000 cycles, certifying its practical applications potential on a wide scale for sodium-based energy storage devices.
对于钠离子混合电容器(SIHC)来说,如何设计具有高存储容量和稳定结构的独特建筑阳极电极材料,以平衡阳极和阴极之间的动力学和容量,是一个巨大的挑战。本文从组织良好的 MnS 纳米颗粒入手,精心设计了引入金属有机框架和双碳装饰的方法,通过电负性诱导制造出理想的双金属硫化物和碳复合材料,并带有碳基质/涂层层。同时形成的丰富硫空位和异质结构可显著提高电子/离子的快速扩散动力学,并诱导出较高的可逆钠离子存储容量。此外,双碳装饰策略使电极具有卓越的电子传导性,保证了出色的结构稳定性,并为电子传输提供了途径,从而使 MnS1-x/ZnS-NC@C (MSZNC) 复合材料在钠离子电池(SIB)中以 10 A g-1 的高倍率循环 1600 次后,仍能保持 354 mAh g-1 的稳定容量。结合理论计算,系统电化学动力学分析结果表明,异质结构和硫空位的协同效应可以提供更多可逆活性位点并促进电荷转移,从而加速反应动力学以增强钠离子存储能力。正如预期的那样,基于 MSZNC 阳极和交流阴极组装的 SIHCs 全电池表现出 116 W h kg-1 的高能量密度和 95 W kg-1 的高功率输出,在 2 A g-1 循环 2000 次的情况下容量保持率为 87%,这证明了其在钠基储能设备方面的广泛实际应用潜力。
Fabrication of knitted Polyethylene/SiO2 composite membrane modules for one-step microfiltration and particle removal in wastewater treatment
Dan Guo, Jianguo Xu, Xiaodong Zhang, Ngie Hing Wong, Jaka Sunarso, Shaomin Liu, Nana Li
doi:10.1016/j.compscitech.2024.110479
编织聚乙烯/二氧化硅复合膜组件,用于废水处理中的一步式微滤和颗粒去除
Sewage treatment efficiency is affected by the membrane module design. In this study, SiO2 was employed as additives in the formation of polyethylene/SiO2 hollow fibre composite membranes using the thermally induced phase separation (TIPS) method. This approach effectively addressed the limitations of pure polyethylene hollow fibres, such as poor network pore structure and low flux. The investigation revealed that the addition of SiO2 enhanced gas flux by 30%, increased porosity by 20%, and provided a commendable tensile strength of 2.1 MPa, suitable for weaving knitted composite membrane module. The voids of the membrane module facilitated particle filtration and microfiltration through micropores of the composite membrane, successfully integrated into a one-step wastewater treatment process. The knitted composite membrane module's particle filtration process effectively intercepted all particles A (30 μm), and the microfiltration process rejected particles B (1.3 < size <15 μm). During these processes, the rejection rate of talc powder in the membrane module was as high as 90%, and the gas flux was remained at 1200 L m−2∙min−1. The strategy of knitted composite membrane modules demonstrates versatility in applications and has the potential for expanding the design to various microporous hollow fibre materials for diverse separation purposes.
污水处理效率受膜组件设计的影响。本研究采用热诱导相分离(TIPS)法,将二氧化硅作为添加剂用于聚乙烯/二氧化硅中空纤维复合膜的形成。这种方法有效地解决了纯聚乙烯中空纤维的局限性,如网络孔隙结构差和通量低。研究表明,加入二氧化硅后,气体通量提高了 30%,孔隙率增加了 20%,抗拉强度达到 2.1 兆帕,适合编织针织复合膜组件。膜组件的空隙有利于通过复合膜的微孔进行颗粒过滤和微过滤,成功地集成到一步式污水处理工艺中。针织复合膜组件的颗粒过滤过程有效地拦截了所有颗粒 A(30 μm),而微滤过程则剔除了颗粒 B(1.3 < 粒径 <15 μm)。在这些过程中,膜组件对滑石粉的截留率高达 90%,气体通量保持在 1200 L m-2∙min-1。编织复合膜组件的策略展示了应用的多样性,并有可能将设计扩展到各种微孔中空纤维材料,以实现不同的分离目的。
Flexible phase change composites with multiple colors and reversible thermochromic for temperature indication and battery thermal management
Yujiao Li, Zhuoni Jiang, Yongsheng Li, Fangfang He, Zhengguo Chen, Xiaoan Li, Peng Wang, Guansong He, Wenbin Yang
doi:10.1016/j.compscitech.2024.110481
具有多种颜色和可逆热致变色功能的柔性相变复合材料,用于温度指示和电池热管理
In this paper, a series of silicone rubber (SR)/thermochromic microcapsules (TC@MF)/cuprous oxide (Cu2O) flexible phase change composites (STC) with multi-colors and reversible thermochromic were prepared. In this composite, SR was used as polymer matrix and TC@MF with phase change enthalpy of 193 J/g was used as functional filler. Moreover, different contents of Cu2O were introduced to change color of composites and improve thermal conductivity and photothermal conversion. The STC composites could undergo reversible color changes from blue-violet to red with a color change temperature of approximately 52 °C. And it exhibited excellent leakage resistance with the leakage rate of STC-2 as low as 0.41%. The thermal conductivity of the STC-3 composite reached 0.33 W m−1 K−1 at Cu2O content of 9 phr. The STC composites were applied to dissipate heat from the battery and the maximum surface temperature was only 49.0 °C at 9.8 A discharge rate which represented 24.03 % reduction in surface temperature compared to the bare battery. This work offers an effective route for preparation of battery thermal regulation materials based on thermochromic microcapsules, which has significant potential for application in the field of battery thermal management.
本文制备了一系列具有多色和可逆热致变色功能的硅橡胶(SR)/热致变色微胶囊(TC@MF)/氧化亚铜(Cu2O)柔性相变复合材料(STC)。在该复合材料中,SR 用作聚合物基体,相变焓为 193 J/g 的 TC@MF 用作功能填料。此外,还引入了不同含量的 Cu2O,以改变复合材料的颜色,并提高热导率和光热转换率。STC 复合材料可以实现从蓝紫色到红色的可逆变色,变色温度约为 52 ℃。此外,STC-2 还具有出色的抗泄漏性能,泄漏率低至 0.41%。当 Cu2O 含量为 9 phr 时,STC-3 复合材料的热导率达到 0.33 W m-1 K-1。STC 复合材料用于电池散热,在放电率为 9.8 A 时,最大表面温度仅为 49.0 °C,与裸电池相比,表面温度降低了 24.03%。这项工作为制备基于热致变色微胶囊的电池热调节材料提供了一条有效途径,在电池热管理领域具有巨大的应用潜力。
Advanced composite armor protection systems for military vehicles: Design methodology, ballistic testing, and comparison
Evangelos Tsirogiannis, Evangelos Daskalakis, Christos Vogiatzis, Foivos Psarommatis, Paulo Bartolo
doi:10.1016/j.compscitech.2024.110486
军用车辆的先进复合装甲防护系统:设计方法、弹道测试和比较
This study presents a new methodology for designing, manufacturing, and testing advanced armor protection systems and applied to the development of three different protection solutions suitable for real armored vehicles. The backplate laminates of the presented composite armor protection solutions were composed of three different materials: steel, aluminum AA6082, and aluminum alloy AA2024 reinforced by multi-walled carbon nanotubes (MWCNTs). The frontal laminates remained the same for the three cases. Keeping almost the same mass while changing the material of each backplate and adapting the thickness, the three different protection systems were ballistically tested and compared according to Level 4 (Level IV) of the standard AEP-STANAG 4569 (projectile 14.5 mm × 114 mm API B32) with real military tests. Furthermore, the performance of the total laminated structure and the performance of each backplate in the total laminated structure were compared in terms of deformation and ballistic fractures. High-quality images acquired by the high-speed camera were helpful in evaluating and comparing the backplates and the entire protection system. The results show that all three protection configurations present high performance mechanical properties and ballistic characteristics compared to commonly used armor systems. Even the under-developed AA2024-CNTs composite is a promising near-term backplate solution.
本研究介绍了一种设计、制造和测试先进装甲防护系统的新方法,并将其应用于开发适合真实装甲车辆的三种不同防护解决方案。所介绍的复合装甲防护解决方案的背板层压板由三种不同的材料组成:钢、铝 AA6082 和由多壁碳纳米管(MWCNTs)增强的铝合金 AA2024。三种方案的正面层压板保持不变。在改变背板材料和厚度的同时,保持几乎相同的质量,对三种不同的防护系统进行了弹道测试,并根据 AEP-STANAG 4569 标准第 4 级(第 IV 级)(射弹 14.5 毫米 × 114 毫米 API B32)与实际军事测试进行了比较。此外,还从变形和弹道断裂的角度对整体层压结构的性能和整体层压结构中每块背板的性能进行了比较。高速摄像机获得的高质量图像有助于评估和比较背板和整个保护系统。结果表明,与常用的装甲系统相比,所有三种防护配置都具有高性能的机械性能和弹道特性。即使是尚未充分开发的 AA2024-CNTs 复合材料也是一种很有前景的近期背板解决方案。
Experimental method for in-situ real-time measurement of mixed mode fibre/matrix interface debonding and comparison of fibre sizings in single short fibre composites
Mehdi Nikforooz, Olivier Verschatse, Lode Daelemans, Karen De Clerck, Wim Van Paepegem
doi:10.1016/j.compscitech.2024.110488
原位实时测量混合模式纤维/基体界面脱胶的实验方法以及单根短纤维复合材料中纤维尺寸的比较
In short fibre composites, off-axis fibres are potentially subject to mixed-mode loading, which results in interactive debonding growth in opening and sliding modes. This synergy might differ for strong and weak fibre/matrix bondings inducing discrete debonding patterns. This study employed an optical visualization technique to investigate, for the first time, the mixed-mode debonding growth for short fibres with different sizings and off-axis angles, through in-situ real-time measurements. For this purpose, embedded single short-fibre specimens were fabricated using E-glass fibres and an epoxy matrix, with a novel and more efficient manufacturing method than done so far in literature. E-glass fibres with two different sizings were utilized, including a polypropylene-compatible (weak) sizing and an epoxy-compatible (strong) sizing. While there was a relatively rapid debonding growth for the transverse fibres with the weak sizing, the strong sizing experienced a gradual debonding growth independent of the fibre angle. For the weak sizing, partial debonding cracks were initiated at different locations along the length of the fibres, where they coalesced into dominant debonding cracks. For the strong sizing, debonding was always initiated and localized at the fibre tip, and there was a clear synchronous propagation of debonding in the arc and length of the fibre.
在短纤维复合材料中,偏离轴线的纤维可能会受到混合模式加载的影响,从而导致开放模式和滑动模式下的交互脱粘增长。这种协同作用可能会因纤维/基体粘合力的强弱而不同,从而诱发离散的脱粘模式。本研究采用光学可视化技术,通过原位实时测量,首次研究了不同尺寸和离轴角的短纤维的混合模式脱胶增长。为此,我们使用 E 玻璃纤维和环氧树脂基体制作了嵌入式单根短纤维试样,与迄今为止的文献相比,这种制作方法更新颖、更高效。使用了两种不同规格的 E 玻璃纤维,包括聚丙烯相容(弱)规格和环氧树脂相容(强)规格。采用弱施胶的横向纤维脱胶相对较快,而采用强施胶的横向纤维则逐渐脱胶,与纤维角度无关。对于弱施胶,部分脱胶裂纹开始出现在纤维长度的不同位置,并在这些位置凝聚成主要的脱胶裂纹。对于强施胶,脱胶总是在纤维顶端开始并局部出现,脱胶在纤维的弧度和长度上明显同步扩展。
Honeycomb-like Polyimide/Fe3O4@PPy foam for electromagnetic wave shielding with excellent absorption characteristics
Wei Chu, Jianwei Li, Jun Lin, Wen Li, Jiazhi Xin, Fei Liu, Xinhai He, Zhonglei Ma, Qiangli Zhao
doi:10.1016/j.compscitech.2024.110489
用于电磁波屏蔽的蜂窝状聚酰亚胺/Fe3O4@PPy 泡沫,具有优异的吸收特性
Electromagnetic interference (EMI) shielding materials with low reflection and excellent microwave absorption characteristics are highly desirable for high-speed electronics devices to attenuate radiated emissions. Herein, we developed a highly absorption dominated composite EMI shielding foams with “honeycomb” structure through chemical foaming and subsequent in situ vapor deposition of polypyrrole (PPy) within polyimide (PI) foams. After the deposition of PPy, the obtained porous PI foams exhibit electrical conductivity of 2.7 × 103 S/m. In addition, the composite foams demonstrate the highest absorption coefficient of 0.8 and EMI shielding efficiency of 41.1 dB with a thickness of 8 mm. Moreover, the optimal reflection loss (RL) of the composite PI/Fe3O4-20@PPy foam (PF/Fe3O4-20@PPy) reach up to −31 dB at 6.0 mm and ≤ −10 dB in the whole X band with a thickness of ≥4 mm. Moreover, the 3D porous structure of PI foam and favorable electrical conductivity of in-situ formed PPy film can contribute to the high sensing performance of PI@PPy foam (PF@PPy). This study provides a novel strategy for the development of lightweight, EMI shielding and microwave absorption materials for advanced applications in flexible anti-radiation and stealth devices.
具有低反射和优异微波吸收特性的电磁干扰(EMI)屏蔽材料是高速电子设备衰减辐射发射的理想材料。在此,我们通过化学发泡,并随后在聚酰亚胺(PI)泡沫中原位气相沉积聚吡咯(PPy),开发出一种具有 "蜂窝 "结构的高吸收主导型复合 EMI 屏蔽泡沫。沉积 PPy 后,得到的多孔 PI 泡沫的导电率达到 2.7 × 103 S/m。此外,复合泡沫的吸收系数最高,为 0.8,EMI 屏蔽效率为 41.1 dB(厚度为 8 毫米)。此外,PI/Fe3O4-20@PPy 复合泡沫(PF/Fe3O4-20@PPy)的最佳反射损耗(RL)在 6.0 mm 时高达 -31 dB,厚度≥4 mm 时整个 X 波段的最佳反射损耗(RL)≤ -10 dB。此外,PI 泡沫的三维多孔结构和原位形成的 PPy 薄膜良好的导电性也有助于 PI@PPy 泡沫(PF@PPy)实现高传感性能。这项研究为开发轻质、电磁干扰屏蔽和微波吸收材料提供了一种新的策略,可用于柔性抗辐射和隐形设备的高级应用。