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 Structures
Analytical study on the behavior of CFRP-concrete bonded joint with a non-rigid end-anchor
Zhou 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.
Mechanical properties of a novel hierarchical cellular structure architectured with minimal surfaces and Voronoi-tessellation
Mu Yanru, Jin Yuan, Ji Han, Wang Weiwei, Zou Sijia, Zhang Chao, Du Jianke
doi: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.
Composites Part A: Applied Science and Manufacturing
Theoretical analysis of phase transition behavior of ALCP/CNT nanocomposites interface by photo and thermal stimulation
Kim Hongdeok, Choi Joonmyung
doi: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.
Constructing flame retardant silica nanoparticles through styrene maleic anhydride copolymer grafting for PC/ABS composites
Zhang Jingfan, Hua Yifang, Liu Jian, Zhu Tao, Sun Jun, Gu Xiaoyu, Li Hongfei, Zhao Jingmao, Zhang Sheng
doi: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 resin
Wang Wei, Liu Yuan, Wang Qi
doi: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.
Facile engineering strategy to control polymer chain structure for enhanced dispersion, electrical and sensing properties of nanocomposites
Na Kim Mi, Lee Hyeseong, Cho Jaehyun, Jun Oh Myung, Hun Kim Seong, Jang Ji-un, Yun Kim Seong
doi: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.
Fabrication and Performance of Ultrathin and Adhesive Composite Film with High Out-of-Plane Thermal Conductivity Using 3D Printing and Microwire-cutting Assistance
Lv Ruicong, Ren Liucheng, Kang Lei, Niu Resouces Hongyu, Bashir Akbar, Bai Shulin
doi: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.
Design, analysis and testing of thermoplastic welded stiffened panels to investigate skin-stringer separation in post-buckling
van Dooren Kevin, Bisagni Chiara
doi: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.
Lightweight, strong, and thermally insulating polybenzoxazine aerogel thermal protection composites for antioxidant ablation long to 1800 s
Xiao Yunyun, Liu Saihui, Zhou Jinlong, Zhang Sizhao, Li Zhenquan, Xiong Shixian, Li Liangjun, Feng Jian
doi: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.
Fabrication of photocatalytic PAN nanofiber membrane loading with TiO2@RGO by electro-spinning & electro-spraying
Niu Linyan, Zhang Baichuan, Sun Jun, Wang Jianjun, Qin Chuanxiang, Dai Lixing
doi: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 Technology
Ultra-sensitive flexible pressure sensor with hierarchical structural laser-induced carbon nanosheets/carbon nanotubes composite film
Guo Xuanqi, Li Yunfan, Zeng Ziran, Zhao Yilin, Lei Xiao, Wang Yaoyu, Guo Dingyi, Liu Feng
doi: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.
