今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 1 篇
Optimization of multi-layered composites against ballistic impact: A mesoscale approach
Shashwat Kapoor, Sonalisa Ray, Jagdish Prasad Sahoo, Yugal Kishor Joshi
doi:10.1016/j.compstruct.2024.118097
多层复合材料抗弹道冲击优化:中尺度方法
There has been an urgent need to develop and analyse multi-layered composite structures with varying material properties to withstand projectile impact. The proposed study focuses on the optimization of the multi-layer composite to achieve maximum resistance/energy dissipation. This study investigates the mechanical performance of the proposed multi-layered composite configuration under high strain rate loading through a computational approach. The proposed multi-layered structure incorporates layers of reinforced concrete, boulders, an elastomer layer, an ultra-high-performance concrete panel, and a layer of steel plate. A mesoscale-based approach has been developed for the layer comprising boulders and mortar. A total of six different configurations have been considered to arrive at the most efficient one against projectile impact. Optimization of the proposed configurations has been done by utilizing the concepts of specific energy absorption and shock impedance. Additionally, the fracture and damage characteristics of each configuration are also studied. Ductile hole enlargement in the sandy soil layer, fragmentation failure in the boulders, petaling failure in the steel plate, and spalling failure in the concrete layer have been observed. Based on the specific energy absorption and shock impedance approaches, the optimum laying sequence for the ballistic impact of each material is suggested.
迫切需要开发和分析具有不同材料性能的多层复合结构以承受弹丸冲击。本研究的重点是优化多层复合材料,以达到最大的阻力/能量耗散。本研究通过计算方法研究了所提出的多层复合材料结构在高应变率载荷下的力学性能。提议的多层结构包括钢筋混凝土层、巨石层、弹性体层、超高性能混凝土板和一层钢板。一种基于中尺度的方法已被开发用于包含巨石和砂浆的层。总共考虑了六种不同的配置,以达到对抗弹丸冲击的最有效配置。利用比能量吸收和冲击阻抗的概念对所提出的结构进行了优化。此外,还研究了每种结构的断裂和损伤特征。观察到砂土层韧性孔扩大、巨石碎裂破坏、钢板花瓣破坏、混凝土层剥落破坏。基于比能吸收法和冲击阻抗法,提出了各种材料在弹道冲击下的最佳敷设顺序。
Influence of carbon black surface characteristics on CB-NR interfacial interaction: Molecular simulation and experimental study
Jihai Xiao, Ziyuan Zhang, Yajie Luan, Sizhu Wu, Youping Wu
doi:10.1016/j.compositesa.2024.108198
炭黑表面特性对CB-NR界面相互作用的影响:分子模拟与实验研究
Carbon black (CB) is the most widely used reinforcing filler in rubber industry, but the effects of CB surface characteristics on interfacial interaction of CB-filled rubber composites are still not fully described. Combined the experimental and molecular simulation techniques, the aim of this study is to individually investigate the influence of various CB surface characteristics, such as surface area, surface crystallite size, roughness and surface energy, on CB-natural rubber (NR) interfacial interaction to obtain a deep interpretation on the properties of rubber composites. Experimental results showed that the specific surface area is the primary factor affecting overall CB-NR interaction, followed by filler network. Meanwhile, CB surface model with different roughness based on experimental parameters were constructed, and the simulation results revealed that CB-NR interfacial interaction mainly occurred at the interface 2–3 nm. The binding energy distribution on CB surface was analyzed, and rough region is weaker than crystal region and amorphous region. The strongest binding sites are located at the junction of rough region and amorphous region. The results in this study are expected to provide a theoretic guide for optimizing the CB characteristics and developing new rubber-grade CB.
炭黑是橡胶工业中应用最广泛的补强填料,但炭黑表面特性对炭黑填充橡胶复合材料界面相互作用的影响尚未得到充分的研究。本研究将实验技术与分子模拟技术相结合,分别研究CB-天然橡胶(NR)的表面表面积、表面晶粒尺寸、粗糙度和表面能等不同表面特征对CB-天然橡胶(NR)界面相互作用的影响,从而对橡胶复合材料的性能进行深入的解释。实验结果表明,比表面积是影响CB-NR整体相互作用的主要因素,其次是填料网络。同时,基于实验参数构建了不同粗糙度的CB表面模型,仿真结果表明CB- nr界面相互作用主要发生在2 ~ 3 nm界面处。分析了炭黑表面的结合能分布,发现粗糙区比结晶区和非晶态区弱。最强的结合位点位于粗糙区和非晶态区交界处。研究结果可为优化丁基橡胶性能和开发新型橡胶级丁基橡胶提供理论指导。
Additive manufacturing and microstructure effects on thermal and mechanical properties of ply-hybrid carbon and glass fiber composites
Cristina Pascual-González, Jesús García-Moreno Caraballo, Iker Lizarralde, David Garoz Gómez, Juan P. Fernández-Blázquez
doi:10.1016/j.compositesb.2024.111446
增材制造及微观结构对复合材料热力学性能的影响
The fiber hybridization in high-strength composites is one of the most researched strategies to enhance their limited toughness. In this work, hybrid composites at laminate level by stacking together plies of carbon and glass fiber were prepared using fused filament fabrication (FFF) technique. The large void content and the poor adhesion between layers attributed to this technology are overcome by the addition of an optimized thermo-pressurized treatment. The analysis of post-processing temperature effects on the microstructural, thermal and interlaminar properties of additive manufactured hybrid composites, revealed a progressive porosity reduction preserving the dimensional accuracy. The enhancement of mechanical properties is due to different contributions that occurred during post-processing: (i) drying effect, which reduces the plasticization of the composites; (ii) improvement of interface adhesion due to the miscibility of polymers; and (iii) significant porosity reduction (below 1%). This work opens a wider space of possibilities, since FFF allows more complex designs than traditional composite manufacturing, and additionally provides an approach to promote molecular diffusion at the interface, which is the most critical region of FFF parts.
高强度复合材料中纤维杂化是提高其极限韧性的研究热点之一。本文采用熔融长丝制造技术(FFF)制备了碳纤维和玻璃纤维层状复合材料。由于该技术导致的空隙含量大和层间粘结力差的问题通过添加优化的热压处理得以克服。分析了后处理温度对复合材料显微组织、热学和层间性能的影响,结果表明,复合材料的孔隙率呈递进式降低趋势,同时保持了尺寸精度。机械性能的增强是由于后处理过程中发生的不同贡献:(1)干燥效应,它降低了复合材料的塑化;(ii)由于聚合物的混相性,界面附着力得到改善;(iii)孔隙率显著降低(低于1%)。这项工作开辟了更广阔的可能性空间,因为FFF允许比传统复合材料制造更复杂的设计,并且还提供了一种促进界面分子扩散的方法,这是FFF零件最关键的区域。
Alternative Inner Filling and Outer Surface Coating of BNNT by Tungsten(VI) Oxide for Supercapacitor Electrode
Honggu Kim, Chandan Kumar Maity, Sada Venkateswarlu, Myung Jong Kim
doi:10.1016/j.compositesb.2024.111436
超级电容器电极用氧化钨(VI)内填充和外涂BNNT的替代方法
The motivation behind this research is to address the need for advanced energy storage materials by exploring the selective filling and coating of boron nitride nanotube (BNNT) with tungsten(VI) oxide (WO3) to enhance the pseudocapacitive performance. In this study, we present a novel synthesis method that allows precise control over the extent of filling and coating, aiming to create tailored hybrid structures. Morphological and structural analysis confirm the filling and coating of BNNT by WO3. Inner filling and outer surface coating of BNNT by WO3 significantly impact on the electrochemical properties. The filling of WO3 within the BNNT can enhance the stability of the system, whereas outer surface coating of BNNT by WO3 improves the capacitive performances. The role of BNNT influences both these phenomena by acting as electrolyte transportation channel as well as stabilizing the WO3. In three electrode study, WO3 coated BNNT showed the maximum specific capacitance of 856 F/g at 1 A/g. An asymmetric supercapacitor device using WO3 coated BNNT as positive electrode revealed the maximum specific capacitance of 137 F/g at 2 A/g current density with an improved energy density of 52 W h/kg. The WO3 coated BNNT-based asymmetric supercapacitor device also showed ∼81% specific capacitance retention after the completion of 10000 GCD cycles, whereas WO3 filled BNNT-based supercapacitor device demonstrated better stability (∼94% specific capacitance retention) due to the filling and stabilization of pseudocapacitive WO3 by BNNT.
本研究的动机是通过探索氮化硼纳米管(BNNT)的选择性填充和氧化钨(WO3)涂层来提高其赝电容性能,以满足对先进储能材料的需求。在这项研究中,我们提出了一种新的合成方法,可以精确控制填充和涂层的程度,旨在创建定制的混合结构。形貌和结构分析证实了WO3对BNNT的填充和包覆。WO3内填充和外表面涂覆对BNNT的电化学性能有显著影响。在BNNT内部填充WO3可以提高体系的稳定性,而在BNNT外表面涂覆WO3则可以提高BNNT的电容性能。BNNT通过作为电解质运输通道和稳定WO3来影响这两种现象。在三电极研究中,WO3涂层的BNNT在1 A/g下的最大比电容为856 F/g。采用WO3包覆BNNT作为正极的非对称超级电容器器件在2 A/g电流密度下的最大比电容为137 F/g,能量密度提高到52 W h/kg。在完成10000次GCD循环后,WO3涂层的BNNT基非对称超级电容器器件也显示出~ 81%的比电容保留率,而WO3填充的BNNT基超级电容器器件由于BNNT填充和稳定了伪电容WO3,表现出更好的稳定性(~ 94%的比电容保留率)。
Constructing a special interface structure of starch/PBAT composites with a novel “many-to-many” strategy
Qiangxian Wu, Yunguo Liu, Kui Jian, Sike Jiang, Fangqing Weng, Chengyue Wu
doi:10.1016/j.compscitech.2024.110593
采用新型“多对多”策略构建淀粉/PBAT复合材料的特殊界面结构
It is a challenge to achieve a high reaction ratio of compatibilizers for improving the compatibility of the composites due to high melt viscosity and short residence time during melt processing. Inspired by the fact that xanthium seeds in nature are easy to combine with animal fur efficiently, a new "many-to-many" melting chemical reaction strategy was proposed to greatly improve the reaction ratio of compatibilizers. In this work, a polycaprolactone-based polyurethane prepolymer (PCLPU) was used to prepare compatible starch/poly(butyleneadipate-co-terephthalate) (PBAT) composites. Polyurethane nanoparticles containing a lot of -NCO groups were prepared and then reacted with tapioca starch with a lot of -OH groups in an intensive mixer to obtain starch/PBAT composite material with a special interface structure. Compared with the biocomposites without PCLPU, the PCLPU-modified biocomposites exhibited compatible morphology and excellent mechanical properties, and the reaction ratio of the PCLPU was as high as 99.2%. The special polyurethane prepolymer interface formed in the composite interacted with the hydrophilic starch granules through urethane linkages and with hydrophobic PBAT through physical PBAT-PBAT linkages. Therefore, the novel strategy used to achieve a special interface structure for improving the mechanical properties of a composite was a simple, efficient, and environmentally friendly method.
在熔体加工过程中,由于熔体粘度高、停留时间短,为提高复合材料的相容性,需要提高相容剂的反应比。利用自然界苍耳种子易于与动物皮毛有效结合的特点,提出了一种新的“多对多”熔融化学反应策略,大大提高了相容剂的反应比例。本文采用聚己内酯基聚氨酯预聚物(PCLPU)制备了相容性淀粉/聚己二酸丁酯-对苯二甲酸酯(PBAT)复合材料。制备了含有大量-NCO基团的聚氨酯纳米颗粒,并与含有大量-OH基团的木薯淀粉在强力混合器中反应,得到具有特殊界面结构的淀粉/PBAT复合材料。与未添加PCLPU的生物复合材料相比,PCLPU改性的生物复合材料具有良好的形态相容性和力学性能,PCLPU的反应率高达99.2%。复合材料中形成的特殊聚氨酯预聚物界面通过聚氨酯键与亲水性淀粉颗粒相互作用,通过物理PBAT-PBAT键与疏水性PBAT相互作用。因此,采用新的策略来实现特殊的界面结构以提高复合材料的力学性能是一种简单、高效和环保的方法。