今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 9 篇,Composites Science and Technology 1 篇
Stiffness degradation of woven roving GFRP due to shear and compression fatigue damage
Akihiko Sato, Yasuo Kitane, Kunitomo Sugiura, Yoshinao Goi
doi:10.1016/j.compstruct.2024.118725
机织粗纱玻璃钢剪切和压缩疲劳损伤引起的刚度退化
Woven roving GFRP is widely used in the structural members of GFRP bridges which are subject to compression or shear stress. However, it is not revealed well about fatigue strength and stiffness degradation under these loading conditions. This study aims to clarify the fatigue strength and residual stiffness of woven roving GFRP under in-plane shear and compression cyclic loading. The specimens were tested at 45 degrees to the fiber direction in the cyclic tensile test, while the compression fatigue test was adjusted to prevent buckling. It is revealed that the in-plane fatigue limit corresponds to the principal strain of about 3700×10^-6. The compression fatigue limit was 40% of the static compression strength. In-plane shear fatigue damage is predominantly due to matrix cracks, and the stiffness degradation appears in Region I, II, and III. The shear stiffness decreased by 20% before the fatigue failure. On the other hand, in the compression fatigue test, matrix cracks hardly occur, and delamination is dominant. The stiffness degradation of Region I is very limited in compression, and stiffness decreased about 10% before the fatigue failure. Moreover, theoretical models are proposed to express the residual stiffness, and they agree well with the experimental value.
编织粗纱GFRP广泛应用于GFRP桥梁的受压或受剪应力的结构构件中。然而,在这些载荷条件下,材料的疲劳强度和刚度退化情况并没有得到很好的揭示。本研究旨在阐明纺纱玻璃钢在面内剪切和压缩循环荷载作用下的疲劳强度和剩余刚度。在循环拉伸试验中,试样在与纤维方向45度的方向上进行试验,压缩疲劳试验中为了防止屈曲进行了调整。结果表明,面内疲劳极限对应的主应变约为3700×10^-6. 压缩疲劳极限为静压强度的40%。面内剪切疲劳损伤以基体裂纹为主,在I区、II区和III区出现刚度退化。在疲劳破坏前,剪切刚度降低了20%。另一方面,在压缩疲劳试验中,基体裂纹几乎不发生,以脱层为主。I区在压缩条件下刚度退化非常有限,在疲劳破坏前刚度下降约10%。建立了剩余刚度的理论模型,与试验值吻合较好。
Structural and material double mechanical enhancement of HAp scaffolds promote bone defect regeneration
Xingyu Gui, Boqing Zhang, Yuxiang Qin, Haoyuan Lei, Xiuwen Xia, Yiyang Li, Haoxiang Lei, Xuerui Zhou, Yanfei Tan, Zhihong Dong, Qi You, Changchun Zhou, Yujiang Fan
doi:10.1016/j.compositesa.2024.108600
羟基磷灰石支架的结构和材料双力学增强促进骨缺损的再生
Critical bone defects caused by trauma, bone tumors, and infections are still challenges in clinical surgery. Digital light processing printing of hydroxyapatite (HAp) scaffolds can fabricate high-resolution personalized bone repair scaffolds. However, creating load-bearing bone regeneration HAp scaffolds with satisfactory mechanical property remain challenging. This study investigated the enhancement of the HAp scaffold mechanical properties from both structural and material perspectives. Structurally, the diamond structure model was optimized to Triply Periodic Minimal Surface structures, increasing the compressive strength of scaffolds from 2.2 to 7.2 MPa. Material-wise, ZnO was incorporated as second-phase particle, improved the compressive strength of HAp scaffolds from 7.2 to 13.7 MPa. Additionally, the incorporation of zinc ions enhanced the bioactivity of the HAp scaffolds. Animal mechanical testing revealed that the enhanced scaffolds effectively supported load-bearing. The HAp/ZnO-TPMS scaffolds exhibited excellent mechanical properties and promoted cellular osteogenic differentiation, showing potential for clinical development and application.
外伤、骨肿瘤、感染引起的严重骨缺损仍是临床外科的难题。羟基磷灰石(HAp)支架的数字光处理打印可以制备高分辨率的个性化骨修复支架。然而,制造具有令人满意力学性能的承重骨再生HAp支架仍然具有挑战性。本研究从结构和材料两方面对HAp支架力学性能的增强进行了研究。在结构上,将金刚石结构模型优化为三周期最小表面结构,将支架抗压强度从2.2提高到7.2 MPa。在材料方面,ZnO作为第二相颗粒加入,使HAp支架的抗压强度从7.2提高到13.7 MPa。此外,锌离子的掺入增强了羟基磷灰石支架的生物活性。动物力学试验表明,增强后的支架能有效地支撑承重。HAp/ZnO-TPMS支架具有优异的力学性能,促进细胞成骨分化,具有临床开发和应用潜力。
Dual hetero-structured Ti composites by manipulating self-assembled powder embedded with nano-reinforcements
Shuhui Feng, Yuanfei Han, Cheng Du, Huaqiang Liu, Fu Chen, Jianwen Le, Kang Wang, Guangfa Huang, Weijie Lu
doi:10.1016/j.compositesb.2024.111999
利用自组装粉末嵌入纳米增强材料制备双异质结构Ti复合材料
Traditional discontinuously micro-reinforced titanium matrix composites (DRTMCs) produced by casting or forging, are usually confronted with the strength-ductility trade-off dilemma. Their micro-scale reinforcements easily cause incompatible deformation and stress localization. Novel self-assembled composite powder embedding nano-reinforcements paired with additive manufacturing technology has great potential to address this dilemma. Here, we report a special dual-heterogeneous structure with micro-scale networks and grain size gradients. It bespoke exciting strength-ductility synergy and excellent uniform elongation surpassing the as-deposited Ti6Al4V alloy by 32%, while manifesting a steadier strain hardening behavior. Primarily, alternating basal and pyramidal slips together with substantial pyramidal <c+a> slips induced by hetero-interfaces significantly improved the uniform deformation ability. Then geometrically necessary dislocation (GNDs) and long-range back stress induced by strain inhomogeneity remarkably enhanced the strain hardening ability. This work firstly determined the most preferred orientation relationship (OR) (58.91°/ ) between TiBw and the adjoining α-Ti in as-deposited composites. These interfaces show higher interface strength (16.42 GPa) than those with the most preferred OR of 0°/ in as-forged TMCs, making more contributions to promoting the load bearing capacity of TiBw. It provided scientific guidance for in-situ synthesizing heterogeneous structures with attractive mechanical properties in Ti composites.
传统的非连续微增强钛基复合材料(DRTMCs)是通过铸造或锻造生产的,通常面临着强度与塑性的权衡困境。它们的微尺度增强容易造成不相容变形和应力局部化。新型自组装复合材料粉末包埋纳米增强材料与增材制造技术相结合,有望解决这一难题。在这里,我们报告了一种特殊的双非均质结构,具有微尺度网络和晶粒尺寸梯度。它具有令人兴奋的强度-塑性协同作用和优异的均匀伸长率,比沉积态Ti6Al4V合金高出32%,同时表现出更稳定的应变硬化行为。主要是基底和锥体交替滑移以及异质界面引起的大量锥体<c+a>滑移显著提高了均匀变形能力。应变不均匀性引起的几何必要位错(GNDs)和长程背应力显著增强了材料的应变硬化能力。本文首先确定了沉积态复合材料中TiBw与相邻α-Ti的最优取向关系(OR)(58.91°/)。这些界面的界面强度(16.42 GPa)高于锻造tmc中最优OR为0°/的界面强度,对提高TiBw的承载能力有更大的贡献。为原位合成具有良好力学性能的Ti复合材料的异相结构提供了科学指导。
Multifunctional Manganese-Based Nanogels Catalyze Immune Energy Metabolism to Promote Bone Repair
Ziyan Huang, Xinzhao Jiang, Lichen Zhang, Wei Wang, Ziang Li, Yiyang Huang, Yichang Xu, Liang Zhou, Jie Wu, Jincheng Tang, Kun Xi, Yu Feng, Liang Chen
doi:10.1016/j.compositesb.2024.112005
多功能锰基纳米凝胶催化免疫能量代谢促进骨修复
Tissue regeneration during bone defect repair is regulated by the energy metabolism of macrophages. Abnormal energy metabolism can negatively affect bone repair in pathological conditions. A promising strategy involves developing biomaterials that regulate macrophage energy metabolism to coordinate immune response and bone regeneration. In this study, hollow mesoporous MnO2, known for its excellent reactive oxygen species (ROS) scavenging and drug-loading abilities, was loaded with dexamethasone. This was followed by electrostatic self-assembly using chitosan coating to create nanogels (Alg-MD@CS). In vitro experiments showed that the nanogel effectively scavenged excess ROS, restored mitochondrial function, and reduced the levels of inflammatory factors. It downregulated glycolysis by inhibiting the ERK/HIF-1α/GLUT1 pathway, facilitating the M1-to-M2 phenotype switch to promote an anti-inflammatory and pro-regenerative ecological environment. In vivo experiments confirmed these findings. The nanogel reduced ROS levels in rats, reshaped the local immune microenvironment, and promoted bone regeneration. In summary, we developed a multifunctional nanogel for bone defect repair and demonstrated the significance and feasibility of reverse reprogramming by regulating the energy metabolism of macrophages during bone regeneration.
骨缺损修复过程中的组织再生受巨噬细胞能量代谢的调控。在病理状态下,异常的能量代谢会对骨修复产生负面影响。一个有希望的策略是开发调节巨噬细胞能量代谢的生物材料,以协调免疫反应和骨再生。在本研究中,以其优异的活性氧(ROS)清除能力和载药能力而闻名的中空介孔MnO2被装载地塞 米松。接下来是静电自组装,使用壳聚糖涂层来制造纳米凝胶(Alg-MD@CS)。体外实验表明,纳米凝胶能有效清除过量的活性氧,恢复线粒体功能,降低炎症因子水平。它通过抑制ERK/HIF-1α/GLUT1通路下调糖酵解,促进m1 - m2表型转换,促进抗炎和促再生的生态环境。体内实验证实了这些发现。纳米凝胶可降低大鼠体内ROS水平,重塑局部免疫微环境,促进骨再生。综上所述,我们开发了一种用于骨缺损修复的多功能纳米凝胶,并证明了通过调节骨再生过程中巨噬细胞的能量代谢进行反向重编程的意义和可行性。
Fabrication of polypropylene/carbon fiber/carbon black composite foam bonded with continuous carbon fiber reinforced polypropylene prepregs via high-pressure foam injection molding
Dongxu Tian, Junji Hou, Jinkai Liang, Jingbo Chen
doi:10.1016/j.compositesb.2024.112006
聚丙烯/碳纤维/炭黑复合泡沫与连续碳纤维增强聚丙烯预浸料粘合的高压泡沫注塑成型
The fabrication of polymer composite foams with several functions offers various advantages. Herein, we reported a highly efficient and mass-produced method for preparing polypropylene/carbon fiber/carbon black (PP/CF/CB) composite foams bonded with continuous CF reinforced PP prepregs. CFs were uniformly dispersed in PP via melt blending, but some agglomerations of CBs were observed owing to their little size. Compared with pure PP, the introduction of CB improved the thermal stability and flame retardance of composites. Owing to the homogeneity of polymer between composites and prepregs, they were well bonded by injection molding. The tensile strength of the samples bonded with prepregs was improved by 158.3–257.7% for different filler contents. As CF and CB played the role of heterogeneous nucleation, and the high-pressure foam injection molding could easily tailor cellular structure by adjusting the holding time and mold temperature, composite foams bonded with two prepregs and with desired cells were successfully prepared. The injected foams with two prepregs had an enhanced electromagnetic interference shielding performance, which was 65.4 dB when the content was 10 wt% and 15 wt% for CF and CB, respectively. This work provides a universal approach for efficient and large-scale preparation of lightweight and multifunctional polymer composite foams.
具有多种功能的高分子复合泡沫材料的制备具有多种优点。本文报道了一种高效、批量生产的聚丙烯/碳纤维/炭黑(PP/CF/CB)复合泡沫材料与连续CF增强PP预浸料粘合的方法。熔体共混使碳纤维均匀地分散在PP中,但由于碳纤维的体积小,出现了团聚现象。与纯PP相比,CB的引入提高了复合材料的热稳定性和阻燃性。由于复合材料和预浸料之间聚合物的均匀性,通过注射成型可以很好地结合。不同填料含量下,预浸料粘结试样的拉伸强度可提高158.3 ~ 257.7%。由于CF和CB发挥了非均相成核的作用,并且高压泡沫注塑成型可以通过调整保温时间和模具温度来方便地定制胞孔结构,因此成功制备了两种预浸料结合并具有所需胞孔的复合泡沫。两种预浸料的注入泡沫具有较好的电磁干扰屏蔽性能,当CF和CB含量分别为10 wt%和15 wt%时,屏蔽效果分别为65.4 dB。本研究为高效大规模制备轻质多功能聚合物复合泡沫材料提供了一种通用方法。
Investigation of two sandwich-structured nanohybrid coating derived from graphene oxide/carbon nanotube on interfacial adhesion and fracture toughness of carbon fiber composites
Qing Wu, Yating Li, Jun Chang, Dan Jin, Bolin Xiao, Renjie Yao, Jianfeng Zhu
doi:10.1016/j.compositesb.2024.112007
氧化石墨烯/碳纳米管两种三明治结构纳米杂化涂层对碳纤维复合材料界面附着力和断裂韧性的影响
Designing stronger interphase towards solving the long-standing dilemma of interfacial delamination is critical for stable application of carbon fiber composites. Herein, nano-scale sandwich-structured coatings, where carbon nanotubes (CNTs) were uniformly anchored on both sides of graphene oxide (GO) layer (abbreviated as C/GO/C) and its reverse, that is double GO layers encapsulated CNT network (G/CNT/G in short), were reported around fiber periphery via vacuum filtration method. The effects of surface structure differences on interfacial shear strength (IFSS) and fracture toughness were compared in epoxy matrix. Impressively, composite incorporating G/CNT/G modified fiber delivered prominent IFSS and interfacial fracture toughness of 114.6 MPa and 137.0 J/m2, 105.7% and 279.5% increases over control fiber composite. This strategy was also superior to C/GO/C and other reported GO and CNT related works. The main factors for maximal IFSS offered by G/CNT/G are that two GO panels enrich active sites to tightly bridge fiber and epoxy, as well as its layered feature and large surface area provide a stable “skeleton” at interphase for stress transfer. Additionally, the G/CNT/G “skeleton” is closer to sandwich structure of iris leaf, in which the porous CNT intermediate network creates larger deformation and adsorb more energy, leading to peak interfacial fracture toughness.
设计更强的界面相以解决长期存在的界面分层问题是碳纤维复合材料稳定应用的关键。本文通过真空过滤的方法,在纤维外围制备了纳米尺度的三明治结构涂层,其中碳纳米管(CNTs)均匀地固定在氧化石墨烯(GO)层(简称C/GO/C)的两侧,其反面是双氧化石墨烯层封装的碳纳米管网络(简称G/CNT/G)。比较了环氧基表面结构差异对界面抗剪强度和断裂韧性的影响。G/CNT/G改性纤维复合材料具有显著的IFSS和界面断裂韧性,分别为114.6 MPa和137.0 J/m2,比对照纤维复合材料提高了105.7%和279.5%。该策略也优于C/GO/C和其他已报道的GO和CNT相关研究。G/CNT/G提供最大IFSS的主要因素是两个氧化石墨烯面板丰富的活性位点紧密桥接纤维和环氧树脂,其分层特性和大表面积在界面提供稳定的“骨架”,用于应力传递。此外,G/CNT/G“骨架”更接近于虹膜叶片的夹层结构,其中多孔的CNT中间网络产生更大的变形和吸附更多的能量,导致界面断裂韧性达到峰值。
Mechanical properties of carbon fiber composites with various wear characteristics during knitting process
Zhaoling Sun, Peixiao Zheng, Chaoyu Chen, Zhijia Dong, Fengxiang Chen, Pibo Ma
doi:10.1016/j.compositesb.2024.112010
不同磨损特性的碳纤维复合材料在针织过程中的力学性能
The inherent brittleness of carbon fiber (CF) presents a significant challenge during the knitting process, as the yarn is prone to breakage under bending stress, resulting in the occurrence of hairiness that directly impacts the mechanical properties of the composites. Therefore, it is imperative to examine the frictional and wear characteristics of CF bundles in order to minimize potential damage incurred during the weaving process and enhance the overall properties of composites. This study initially modified the CF through flexible coating with polydimethylsiloxane (PDMS), followed by preparing a knitted preform. Subsequently, an investigation was conducted to assess the impact of contact area and sinking depth on CF damage. Furthermore, the finite element method was employed to simulate stress distribution during the loop formation of CF. Finally, the impact of CF wear on the mechanical characteristics of the composite was examined. After heat treatment and low damage treatment, the tensile strength and bending strength of CF@PDMS/TD-C increased by 16.7% and 23.64%, respectively. The energy absorption performance was measured at 17.79 J, 27.84 J, 37.77 J, and 42.34 J for impact energies of 20 J, 30 J, 40 J, and 50 J, respectively. These findings establish an experimental and theoretical foundation for mitigating damage during the weaving process.
碳纤维(CF)固有的脆性在编织过程中提出了一个重大挑战,纱线在弯曲应力下容易断裂,导致毛羽的产生,直接影响复合材料的力学性能。因此,研究碳纤维束的摩擦磨损特性,以减少编织过程中潜在的损伤,提高复合材料的整体性能是十分必要的。本研究首先通过聚二甲基硅氧烷(PDMS)柔性涂层对CF进行改性,然后制备针织预成型。随后,对接触面积和下沉深度对CF损伤的影响进行了研究。在此基础上,采用有限元方法模拟了碳纤维环成形过程中的应力分布。最后,研究了碳纤维磨损对复合材料力学特性的影响。经过热处理和低损伤处理后,CF@PDMS/TD-C的抗拉强度和抗弯强度分别提高了16.7%和23.64%。在冲击能量为20 J、30 J、40 J和50 J时,分别测量了17.79 J、27.84 J、37.77 J和42.34 J的吸能性能。这些研究结果为减轻织造过程中的损伤提供了实验和理论基础。
Boosted Triboelectric Performance in Stretchable Nanogenerators via 2D MXene-Driven Electron Accumulation and LiNbO₃-Assisted Charge Transfer
Biswajit Mahanty, Sujoy Kumar Ghosh, Dong-Weon Lee
doi:10.1016/j.compositesb.2024.111995
通过二维mxene驱动的电子积累和LiNbO 3辅助的电荷转移提高可拉伸纳米发电机的摩擦电性能
The development of piezoelectrically enhanced triboelectric hybrid nanogenerators (PET-HNGs) has garnered considerable attention for their potential in energy harvesting. However, their performance in stretchable applications across diverse environments, such as air and water, remains limited due to the lack of high-performance, stretchable material compositions and a comprehensive understanding of the charge transfer mechanism involved. To address these challenges, we have designed a high-performance, stretchable nano-/micro-composite film by embedding 2D MXene nanosheets and piezoelectric LiNbO3 microparticles into an Ecoflex polymer matrix. Quantum mechanical calculations revealed that MXene nanosheets significantly increase electron density near the Fermi level, while LiNbO3 microparticles enhance electron transfer during contact electrification with polydimethylsiloxane (PDMS). This synergistic effect resulted in a substantial enhancement of the triboelectric energy harvesting performance, with the composite film exhibiting a 355% increase in voltage, a 324% increase in current, and a 100% boost in power output density compared to systems using pure Ecoflex based TENGs. The fabricated PET-HNG demonstrated remarkable output metrics, including a voltage of 455 V, current of 140 μA, power output density of 15.6 W m-2, and an energy conversion efficiency of 78.5%, all while maintaining exceptional performance stability even under mechanical stretching.This stretchable nanogenerator shows great potential as a self-powered wearable sensor for real-time biomechanical monitoring in various environments, including air and underwater. This innovation paves the way for the development of next-generation wearable electronics and energy harvesting devices.
压电增强摩擦电混合纳米发电机(PET-HNGs)因其在能量收集方面的潜力而受到广泛关注。然而,由于缺乏高性能、可拉伸的材料成分和对所涉及的电荷转移机制的全面理解,它们在不同环境(如空气和水)的可拉伸应用中的性能仍然有限。为了解决这些挑战,我们通过将2D MXene纳米片和压电LiNbO3微粒嵌入Ecoflex聚合物基质中,设计了一种高性能、可拉伸的纳米/微复合薄膜。量子力学计算表明,MXene纳米片显著提高了费米能级附近的电子密度,而LiNbO3微粒子在与聚二甲基硅氧烷(PDMS)接触带电过程中增强了电子转移。这种协同效应大大提高了摩擦电能量收集性能,与使用纯Ecoflex的teng系统相比,复合薄膜的电压提高了355%,电流增加了324%,输出功率密度提高了100%。制备的PET-HNG具有优异的输出性能,电压为455 V,电流为140 μA,输出功率密度为15.6 W m-2,能量转换效率为78.5%,即使在机械拉伸下也能保持优异的性能稳定性。这种可拉伸的纳米发电机显示出巨大的潜力,可以作为一种自供电的可穿戴传感器,在各种环境中进行实时生物力学监测,包括空气和水下。这一创新为下一代可穿戴电子设备和能量收集设备的发展铺平了道路。
Ultratough Nacre-inspired Soybean Protein Isolate/Graphene Nanocomposite with Flame-retardant, Thermal Conductivity and Recyclable
Tao Liu, Zheng Liu, Weidong Gu, Jieyu Zhang, Shanshan Gong, Jianzhang Li
doi:10.1016/j.compositesb.2024.111998
具有阻燃性、导热性和可回收性的超韧大豆分离蛋白/石墨烯纳米复合材料
Bioplastics synthesized from soybean protein isolate (SPI) and graphite are promising alternatives but often suffer from their inability of mass production, high-cost, poor mechanical robustness, and even flammability. Herein, the scalable production of nacre-like nanocomposite by using the ball-milling spray method of graphene/SPI materials is demonstrated. The dynamic non-covalent was employed to facilitate the toughening effect of inorganic nano-fillers, while simultaneously utilizing dynamic covalent supramolecular interactions to realize plasticizer reinforcement materials. The dissipation of stress is facilitated through a combination of covalent and non-covalent interactions, thereby enhancing the interface interaction and resulting in materials with superior mechanical properties. The interfacial interaction between the SPI and the nano-reinforce confer exceptional mechanical properties to the bioplastic, achieving an excellent tensile strength 11.01 ± 0.81 MPa and fracture toughness14.52 ± 0.71 MJ/m3, which are 3.4 and 3.5 times, respectively, those of neat SPI. The recycling for highly reinforced nacre-mimetic SPI-based nanocomposites is critically enabled by the dynamic bond and improves the sustainability of bioinspired nanocomposites in cyclic economy. In addition, the SPI composite has exceptional flame retardancy, thermal conductivity, and electromagnetic shielding properties. This study provides new insights into the design of reliable and environmentally friendly biomaterials, which is significant for the development of sustainable development resources.
以大豆分离蛋白(SPI)和石墨为原料合成生物塑料是一种很有前途的替代材料,但往往存在无法批量生产、成本高、机械坚固性差、甚至易燃性差的问题。本文演示了利用石墨烯/SPI材料的球磨喷涂方法可大规模生产类纳米复合材料。利用动态非共价来促进无机纳米填料的增韧效果,同时利用动态共价超分子相互作用来实现增塑剂增强材料。通过共价和非共价相互作用的结合,促进应力的消散,从而增强界面相互作用,从而使材料具有优越的力学性能。SPI与纳米增强剂的界面相互作用使生物塑料具有优异的力学性能,抗拉强度为11.01±0.81 MPa,断裂韧性为14.52±0.71 MJ/m3,分别是纯SPI的3.4倍和3.5倍。高增强纳米复合材料的循环利用是动态键的关键,提高了生物纳米复合材料在循环经济中的可持续性。此外,SPI复合材料具有优异的阻燃性、导热性和电磁屏蔽性能。本研究为设计可靠、环保的生物材料提供了新的思路,对可持续发展资源的开发具有重要意义。
Additive Manufacturing of Continuous Carbon Fiber/Epoxy Composites with Structured Core-Shell Towpreg: Methods, Characterization, and Mechanics
Kaiyue Deng, Md Habib Ullah Khan, Soyeon Park, Dae Han Sung, Kelvin Fu
doi:10.1016/j.compositesb.2024.112001
碳纤维/环氧树脂复合材料的增材制造:方法、表征和力学
Continuous carbon fiber thermoset composites are acclaimed for their exceptional structural integrity, environmental durability, and extended service life, yet their additive manufacturing (AM) has been relatively underexplored. This study investigates the mechanical performances of 3D-printed continuous carbon fiber/epoxy composites fabricated using the Tow-Preg Cladding (TPC) method. This novel approach integrates in-situ epoxy impregnation, dual-cure cladding, and tow-preg deposition to enhance the producibility of such composites via AM. The resulting composite showcases a fiber volume fraction exceeding 50%, offering remarkable mechanical properties. We report a tensile strength of 1295.72 MPa, a compressive strength of 544.13 MPa, a flexural strength of 659.30 MPa, and an interlaminar shear strength of 50.87 MPa. Furthermore, the tensile strength and modulus achieved 41.5% and 58.1% of the values predicted by a modified rule of mixture equation, indicating competitive performance among various AM systems for continuous fiber composites. By addressing challenges in uniform fiber distribution and optimizing composite morphology, this research marks a significant advancement in AM for thermally curable thermoset composites. The comparative analysis of diverse AM techniques positions our TPC approach as a promising solution in the field, potentially transforming future high-performance composite fabrication.
连续碳纤维热固性复合材料因其卓越的结构完整性、环境耐久性和延长的使用寿命而备受赞誉,但其增材制造(AM)的探索相对不足。本文研究了采用TPC (Tow-Preg覆层)法制备的3d打印连续碳纤维/环氧复合材料的力学性能。这种新颖的方法集成了原位环氧浸渍、双固化包层和双预浸沉积,以提高增材制造复合材料的可生产性。所得复合材料的纤维体积分数超过50%,具有卓越的机械性能。我们报告的抗拉强度为1295.72 MPa,抗压强度为544.13 MPa,抗折强度为659.30 MPa,层间剪切强度为50.87 MPa。此外,拉伸强度和模量分别达到了修正混合方程规则预测值的41.5%和58.1%,表明了各种增材制造系统在连续纤维复合材料中的竞争力。通过解决纤维均匀分布和优化复合材料形态的挑战,该研究标志着增材制造在热固化热固性复合材料方面取得了重大进展。通过对各种增材制造技术的比较分析,我们的TPC方法在该领域是一种很有前途的解决方案,有可能改变未来的高性能复合材料制造。
Flame-retardant and thermal insulating biomass aerogel with super-elasticity
Ting Wang, Cheng Xu Xu, Ning Yu, Wen-Li An, Wei luo, Hai-Bo Zhao, Fu-Rong Zeng, Ming-Jun Chen
doi:10.1016/j.compositesb.2024.112004
超弹性阻燃保温生物质气凝胶
Biomass aerogels possessing both resilience and flame retardance exhibit great potential as alternatives to fossil-based thermal insulators. Nevertheless, the functional applications of elastic biomass aerogels are impeded by their poor resilience persistence, especially at low temperatures. Herein, a synergetic strategy was proposed for designing biomass aerogels with exceptional elasticity across a broad temperature range (from 150 °C to −78 °C), by strategically manipulating their microstructure and implementing a chemically cross-linked network. The resultant aerogels suffered from slight plastic deformation of only 6.1 % even after 1000 loading-unloading cycles at a strain of 60 %, manifesting super-elastic performance. Additionally, the structure and resilience of aerogel can be well maintained even under frigid temperatures (−78 °C). Because firmly cross-linked networks and loosely packed microstructures with elongated cell walls were constructed to minimize plastic deformation and bending stress, thereby suppressing structural destruction. Furthermore, the resulting biomass aerogel exhibited a remarkable combination of advantageous properties including lightweight, flame retardance (limiting oxygen index of 29 %), thermal insulation (32.8 mW m−1 K−1) and infrared stealth. This research offers new insights into the design of elastic biomass aerogels with exceptional overall performance.
具有弹性和阻燃性的生物质气凝胶作为化石基绝热材料的替代品显示出巨大的潜力。然而,弹性生物质气凝胶的功能应用受到其弹性持久性差的阻碍,特别是在低温下。本文提出了一种协同策略,通过战略性地操纵其微观结构并实现化学交联网络,设计出在宽温度范围(从150°C到- 78°C)内具有优异弹性的生物质气凝胶。在60%的应变下,即使经过1000次加载-卸载循环,气凝胶也仅发生6.1%的轻微塑性变形,表现出超弹性性能。此外,即使在低温(- 78°C)下,气凝胶的结构和弹性也能很好地保持。因为构建牢固的交联网络和具有细长细胞壁的松散排列的微结构可以最大限度地减少塑性变形和弯曲应力,从而抑制结构破坏。此外,所得到的生物质气凝胶具有轻质、阻燃(极限氧指数为29%)、绝热(32.8 mW m−1 K−1)和红外隐身等优点。该研究为具有优异综合性能的弹性生物质气凝胶的设计提供了新的见解。
Enhancement of radar-infrared stealth performance of EPDM-based composites through the asymmetric sandwich structural construction
Zikang Han, Rong Chen, Jiang Li, Shaoyun Guo
doi:10.1016/j.compscitech.2024.110981
非对称夹层结构增强epdm基复合材料雷达红外隐身性能
The development of radar-infrared-compatible stealth materials is crucial for the weaponry stealth field. However, reconciling the mechanistic contradiction between radar and infrared stealth remains a challenge. In this study, an asymmetrical sandwich structure composite was developed, with an absorbing layer situated in the middle and low emissivity layers on either side. The structure and properties of the functional layers were optimized: In the absorbing layer, ethylene propylene diene monomer/carbon nanotubes/silica (EPDM/CNTs/SiO2) was foamed to enhance its microwave absorption and thermal insulation properties. In the low emissivity layers, the orientation of the flake aluminum powders was adjusted to reduce the infrared emissivity to as low as 0.236 and 0.183 at 3∼5 and 8∼14μm, respectively. As a result, the composite achieved an effective absorption bandwidth of 7.26 GHz and maintained an equilibrium temperature of 29.4 °C after being placed on a 60 °C hot stage, demonstrating excellent infrared stealth performance. Additionally, the composite has a suitable density (0.77 g/cm3) and thickness (3.58 mm). Considering its broad bandwidth, low emissivity, lightness, and softness, the sandwich structure composite is suitable for compatible stealth applications.
雷达-红外兼容隐身材料的研制是武器隐身领域的关键。然而,协调雷达隐身与红外隐身之间的机理矛盾仍然是一个挑战。本研究开发了一种非对称夹层结构复合材料,吸收层位于中间,两侧为低发射率层。对功能层的结构和性能进行了优化:在吸波层中,采用乙丙二烯单体/碳纳米管/二氧化硅(EPDM/CNTs/SiO2)进行发泡,增强其微波吸收和保温性能;在低发射率层中,调整片状铝粉的取向,使其在3 ~ 5 μm和8 ~ 14μm处的红外发射率分别降至0.236和0.183。结果表明,该复合材料放置在60℃高温台上后,有效吸收带宽为7.26 GHz,平衡温度为29.4℃,具有优异的红外隐身性能。此外,该复合材料具有合适的密度(0.77 g/cm3)和厚度(3.58 mm)。该复合材料具有宽带宽、低发射率、轻、柔软等特点,适合兼容隐身应用。