今日更新:Composite Structures 3 篇,Composites Part B: Engineering 6 篇,Composites Science and Technology 3 篇
Composite curved hourglass cellular structures: design optimization for stiffness response and crashworthiness performance
Amin Farrokhabadi, Dimitrios Chronopoulos
doi:10.1016/j.compstruct.2023.117834
复合材料曲面沙漏蜂窝结构:刚度响应和防撞性能的优化设计
Auxetic lattice structures are known for their superior stiffness-to-density and strength-to-density ratios. Re-entrant hourglass exhibits an acceptable equivalent elastic modulus and remarkable energy absorption capacity among various auxetic configurations due to their flexibility and hinge deflecting during crushing loads. This study introduces a curved hourglass honeycomb which can be produced using 3D printing with pure or reinforced filaments incorporating continuous fibers. New closed-form formulations are analytically derived using an energy method by considering an extracted unit cell to predict the equivalent in-plane mechanical properties for the first time. The plateau stress of the proposed honeycomb is evaluated at the densification state of a unit cell using the energy conservation theory, equating external work with plastic energy dissipation. The accuracy of these extended relations is validated against experimental outcomes, demonstrating good agreement between analytical and experimental results. Additionally, robust linear and nonlinear finite element analyses are conducted to assess the accuracy of the obtained relations, including the equivalent stiffness and plateau stress for structures produced with reinforced filaments. The nonlinear finite element code employs appropriate subroutines to model plasticity/damage events. Based on the established analytical relations for stiffness and plateau stress, multi-objective optimization using Genetic Algorithm is applied to define optimum values for the Pareto front chart's objective functions of stiffness and plateau stress. The optimization process involves exploring the design space and defining the values of geometrical parameters to achieve the desired objectives. In conclusion, this study presents a novel approach to developing curved re-entrant honeycomb structures, with analytical formulations validated against experimental and numerical results. Optimization helps to identify optimal configurations concerning stiffness and plateau stress, offering potential applications in lightweight and high-strength materials design. According to the obtained results, for selection of the best value for curved strut angle which results in the optimum value of stiffness and plateau stress, a range between 10°-34° can be considered depending on the volume fraction of fibers.
辅助晶格结构以其优异的刚度密度比和强度密度比而闻名。在各种辅助结构中,重入式沙漏具有可接受的等效弹性模量和显著的能量吸收能力,这得益于它们的柔韧性和挤压载荷时的铰链偏转。本研究介绍了一种弧形沙漏蜂窝材料,这种材料可通过三维打印技术用纯纤维丝或包含连续纤维的增强纤维丝制成。通过考虑提取的单元格,使用能量法分析得出了新的闭式公式,首次预测了等效面内力学性能。利用能量守恒理论,将外功等同于塑性能量耗散,在单元格的致密化状态下评估了拟议蜂窝的高原应力。实验结果验证了这些扩展关系的准确性,表明分析结果与实验结果之间具有良好的一致性。此外,还进行了稳健的线性和非线性有限元分析,以评估所获得关系的准确性,包括使用增强丝制作的结构的等效刚度和高原应力。非线性有限元代码采用适当的子程序来模拟塑性/损伤事件。根据已建立的刚度和高原应力分析关系,采用遗传算法进行多目标优化,以确定帕累托前线图的刚度和高原应力目标函数的最佳值。优化过程包括探索设计空间和确定几何参数值,以实现预期目标。总之,本研究提出了一种开发曲面重入式蜂窝结构的新方法,并根据实验和数值结果验证了分析公式。优化有助于确定有关刚度和高原应力的最佳配置,为轻质和高强度材料设计提供了潜在应用。根据所获得的结果,要选择能产生最佳刚度和高原应力值的最佳弯曲支杆角度值,可根据纤维的体积分数在 10°-34° 之间进行考虑。
Design of manufacturable variable stiffness composite laminates using spectral Chebyshev and normalized cut segmentation methods
Mohammad Sheikhi, Mirmeysam Rafiei Anamagh, Bekir Bediz, Lutfi Taner Tunc
doi:10.1016/j.compstruct.2023.117836
利用切比雪夫光谱法和归一化切割分割法设计可制造的可变刚度复合材料层压板
The in-plane fiber orientations of variable stiffness (VS) laminates can be tailored to achieve enhanced structural properties compared to conventional constant stiffness (CS) laminates. However, VS laminate manufacturing faces challenges such as wrinkles, gaps, and overlaps. To address these challenges, we present a novel three-step design methodology. First, the laminate is modeled using lamination parameters (LPs) and the spectral Chebyshev method, and the optimal LPs are determined to maximize the fundamental frequency. Then, the discrete fiber angles are retrieved using the optimal LP distribution. Lastly, a normalized-cut segmentation method is applied to divide the domain into clusters and to generate manufacturable curvilinear fiber paths. Case studies focusing on designing clusters containing both straight and curvilinear fiber paths demonstrate that the designed VS composites can significantly enhance the dynamic performance with up to 20% enhancement in the fundamental frequency compared to CS laminates, under fully clamped boundary conditions with manufacturing constraints.
与传统的恒定刚度(CS)层压板相比,可变刚度(VS)层压板的面内纤维取向可根据需要进行调整,以获得更强的结构特性。然而,VS 层压板的制造面临着褶皱、间隙和重叠等挑战。为了应对这些挑战,我们提出了一种新颖的三步设计方法。首先,使用层压参数(LP)和频谱切比雪夫方法对层压板进行建模,并确定最佳 LP,以最大限度地提高基频。然后,利用最优 LP 分布检索离散纤维角。最后,应用归一化切割分割法将域划分为簇,并生成可制造的曲线光纤路径。案例研究的重点是设计包含直线和曲线纤维路径的簇,结果表明,与 CS 复合材料相比,设计的 VS 复合材料能显著提高动态性能,在完全夹紧的边界条件和制造限制条件下,基频最多可提高 20%。
Elliptical concrete-filled FRP tubes with an embedded H-shaped steel under axial compression and cyclic lateral loading: Experimental study and modelling
Bing Zhang, Yutao Peng, Sumei Zhang, Shuhong Lin, Chong Zhou, Guan Lin
doi:10.1016/j.compstruct.2023.117839
带有嵌入式 H 型钢的椭圆形混凝土填充玻璃钢管在轴向压缩和循环侧向载荷作用下的性能:实验研究与建模
Concrete-filled FRP tubes (CFFTs) have found increasing applications due to their superior ductility and remarkable corrosion resistance. In published literature, circular CFFTs and rectangular CFFTs have been investigated extensively, while there are relatively few studies on elliptical CFFTs. There is no research about elliptical CFFTs with an embedded H-shaped steel (i.e., HS-ECFFTs) under axial compression and cyclic lateral loading. Against this background, this paper investigated the seismic behaviour of HS-ECFFTs experimentally and numerically. Test results indicated that: (1) all HS-ECFFTs performed well with remarkable energy dissipation ability; (2) due to the effective FRP confinement, the local buckling of the H-shaped steel was prohibited; (3) the elliptical aspect ratio had limited influences on the ductility, the stiffness degradation and the energy dissipation; (4) the FRP thickness, after a certain threshold, showed beneficial but limited influences on the peak load, the stiffness degradation and the energy dissipation; (5) the HS-ECFFT specimen performed much better in terms of the peak load, the ductility, the stiffness degradation and the energy dissipation when it was bending around the strong axis. The proposed numerical model established on the OpenSees platform could generate reasonably accurate numerical results for all HS-ECFFTs.
混凝土填充玻璃纤维管道(CFFT)因其优越的延展性和显著的耐腐蚀性,应用日益广泛。在已发表的文献中,对圆形 CFFT 和矩形 CFFT 进行了广泛研究,而对椭圆形 CFFT 的研究相对较少。目前还没有关于在轴向压缩和循环侧向荷载下嵌入 H 型钢的椭圆 CFFT(即 HS-ECFFT)的研究。在此背景下,本文对 HS-ECFFT 的抗震性能进行了实验和数值研究。试验结果表明(1) 所有 HS-ECFFT 均表现良好,具有显著的耗能能力;(2) 由于玻璃钢的有效约束,H 型钢的局部屈曲被禁止;(3) 椭圆形长宽比对延性、刚度退化和耗能的影响有限;(5) HS-ECFFT 试样在绕强轴弯曲时,在峰值载荷、延性、刚度退化和能量耗散方面表现更好。在 OpenSees 平台上建立的拟议数值模型可以为所有 HS-ECFFT 生成相当精确的数值结果。
A comparative study on the low velocity impact behavior of UD, woven, and hybrid UD/woven FRP composite laminates
Binlin Ma, Xiaofei Cao, Yu Feng, Yujian Song, Fei Yang, Ying Li, Deyue Zhang, Yipeng Wang, Yuting He
doi:10.1016/j.compositesb.2023.111133
关于 UD、编织和 UD/ 编织混合 FRP 复合层压板低速冲击行为的比较研究
This study is aimed at comparing the response and damage of unidirectional (UD), woven fabric (WF) and hybrid UD/WF fiber reinforced polymer (FRP) laminates subjected to low velocity impact. The unidirectional tape and/or woven fabric (plain weave) carbon/epoxy prepregs are laminated and hot-pressed to produce UD, WF and sandwich-like hybrid UD/WF specimens. Impact responses of specimens are determined through low velocity impact (LVI) tests with impact energies of 10 J, 17 J and 25 J. After the LVI tests, the damage of specimens is characterized and analyzed using a combination of visual inspection, ultrasonic phased-array inspection, micro-computed tomography (CT) inspection, cross-sectional microscopic observation, and thermal de-ply test. Also, the LVI damage mechanisms of the three types of specimens are quantitatively compared by using the inter fiber crack volume ratio, total delamination area and fiber fracture length. It is concluded that the fiber architecture plays an important role in determining low velocity impact behavior of composite laminates. Especially, for the sandwich-like hybrid UD/WF laminates whose surface is a WF layer and the core is a UD layer, the WF layer on the surface plays an important role in reducing matrix cracking, delamination and fiber fracture, thus improving its LVI resistance.
本研究旨在比较单向(UD)、编织(WF)和 UD/WF 混合纤维增强聚合物(FRP)层压板在受到低速冲击时的响应和损坏情况。单向带和/或编织物(平纹)碳/环氧预浸料经层压和热压后可制成 UD、WF 和夹层式混合 UD/WF 试样。试样的冲击响应通过冲击能量为 10 J、17 J 和 25 J 的低速冲击(LVI)试验来确定。在 LVI 试验后,结合使用目视检查、超声相控阵检查、微型计算机断层扫描(CT)检查、横截面显微镜观察和热脱附试验,对试样的损伤进行表征和分析。此外,还利用纤维间裂纹体积比、总分层面积和纤维断裂长度对三种试样的 LVI 损伤机制进行了定量比较。结论是,纤维结构在决定复合材料层压板的低速冲击行为方面起着重要作用。特别是对于表面为 WF 层、核心为 UD 层的三明治状 UD/WF 混合层压板,表面的 WF 层在减少基体开裂、分层和纤维断裂方面发挥了重要作用,从而提高了其抗低速冲击性能。
Fire-retardant braided electronic rope with a hierarchical core-shell structure for fire rescue operations
Haoran Gong, Zhiyong Peng, Yingcun Liu, Ze Chen, Shiyu Fei, Ruoxian Xu, Keshuai Liu, Duo Xu, Yizhu Guo
doi:10.1016/j.compositesb.2023.111152
用于消防救援行动的具有分层芯壳结构的阻燃编织电子绳索
Effective rope rescue is crucial for evacuating individuals trapped in high-rise fires and for ensuring their safety in extreme fire environments. However, conventional fire rescue ropes often prioritize mechanical properties and flame retardancy, neglecting the crucial aspects of escape monitoring and position acquisition. Herein, we present a facile strategy to fabricate flame-retardant braided electronic rope (FBER) with a core-shell structure by large-scale braiding techniques. The pressure-sensing performance of the FBER was optimized by altering the braiding structure, which relies on the cross-contact between the core-braided composite yarns (CBCYs) at the sensing point. The unique structural design of FBER effectively prevents thermal transfer, ensuring pressure-sensing stability in extreme environments. Our results demonstrate that the FBER exhibits high sensitivity, rapid response, and excellent durability over 3500 cycles at 200 °C. The optimized FBER can be integrated into fire rescue detection systems for real-time escape monitoring, position acquisition, and safety detection during fire rescue operations. The scalable and multifunctional design of the FBER can significantly aid the development of fire rescue ropes.
有效的绳索救援对于疏散高层火灾中的被困人员以及确保他们在极端火灾环境中的安全至关重要。然而,传统的消防救援绳索往往优先考虑机械性能和阻燃性能,而忽视了逃生监测和位置获取等关键环节。在此,我们提出了一种通过大规模编织技术制造具有芯壳结构的阻燃编织电子绳(FBER)的简便策略。通过改变编织结构,FBER 的压力传感性能得到了优化,这主要依赖于传感点处芯壳编织复合纱线(CBCY)之间的交叉接触。FBER 的独特结构设计有效地防止了热传递,确保了在极端环境下的压力传感稳定性。我们的研究结果表明,FBER 具有灵敏度高、响应速度快的特点,并且在 200 °C 的条件下可循环使用 3500 次,经久耐用。经过优化的 FBER 可集成到消防救援检测系统中,用于消防救援行动中的实时逃生监测、位置采集和安全检测。FBER 的可扩展性和多功能设计可极大地促进消防救援绳索的发展。
Color adjustable, mechanically robust, flame-retardant and weather-resistant TiO2/MMT/CNF hierarchical nanocomposites coatings toward intelligent fire cyclic warning and protection
Yan-Bin Shen, Ke-Xin Yu, Ye-Jun Wang, Yun-Hao Qu, Long-Qian Pan, Cheng-Fei Cao, Kun Cao, Jie-Feng Gao, Yongqian Shi, Pingan Song, Jianming Yong, Min Hong, Guo-Dong Zhang, Li Zhao, Long-Cheng Tang
doi:10.1016/j.compositesb.2023.111159
颜色可调、机械坚固、阻燃和耐候的 TiO2/MMT/CNF 分层纳米复合材料涂层,用于智能火灾循环预警和保护
Fire safety and protection are very important but still show a critical global challenge. Developing smart fire warning materials with combined passive flame retardancy and active fire alarm response is promising for reducing or avoiding blade fire disasters. Various nano-fillers (e.g., graphene oxide and MXene) based coatings have proven to be effective fire warning material for monitoring high fire risk of various combustible materials; however, they still show some shortages, for example, high cost, black color, poor weather resistance and complicated fabricating process. Here, we report a green, cost effective and large-scale strategy for fabricating water-based 3D-titania/2D-montmorillonite/1D-celluose nanofiber (TiO2/MMT/CNF) hierarchical nanocomposite coatings with adjustable color, mechanical robustness, good flame retardancy, long-term weather resistance and sensitive fire cyclic alarming response. The formation of strong chemical bonding and hydrogen bonding interactions among polyethylene glycol molecules and multi-scale nano-fillers together with silane surface modification can produce good mechanical flexibility (folded crane), surface hydrophobicity (water contact angle of 152°) and exceptional flame resistance (good structure integrity after 120 s flame exposure). Notably, the optimized nanocomposite coatings exhibit ultrafast fire alarm response (<3.5 s) and stable fire cyclic alarming capability via the possible band transition of the TiO2 network under flame. Further, such color-adjustable nanocomposite coatings can be easily fabricated for large-scale production, and they show excellent stable flame retardancy and stable fire cyclic warning response even after more than one-year outdoor exposure. This work provides a novel and green fire warning nanocomposite coatings with combined passive-active functionalities for fire warning and protection.
消防安全和保护非常重要,但仍然是一个严峻的全球性挑战。开发兼具被动阻燃性和主动火灾报警响应功能的智能火灾预警材料,对于减少或避免叶片火灾灾难大有可为。各种基于纳米填料(如氧化石墨烯和 MXene)的涂层已被证明是有效的火灾预警材料,可用于监测各种可燃材料的高火灾风险;但它们仍存在一些不足,如成本高、颜色黑、耐候性差、制造工艺复杂等。在此,我们报告了一种绿色、低成本、大规模制造水基三维-钛/二维-蒙脱石/一维-纤维素纳米纤维(TiO2/MMT/CNF)分层纳米复合涂层的策略,该涂层具有颜色可调、机械坚固、阻燃性好、长期耐候性和灵敏的火灾循环报警响应等特点。聚乙二醇分子与多尺度纳米填料之间形成的强化学键和氢键相互作用,再加上硅烷表面改性,可产生良好的机械柔韧性(折叠式起重机)、表面疏水性(水接触角为 152°)和优异的阻燃性(120 秒火焰暴露后仍具有良好的结构完整性)。值得注意的是,优化后的纳米复合涂层具有超快的火灾报警响应(<3.5 秒)和稳定的火灾循环报警能力,这是通过二氧化钛网络在火焰下可能发生的带跃迁实现的。此外,这种颜色可调的纳米复合材料涂层易于制造,可进行大规模生产,即使在室外暴露一年以上,也能表现出优异的稳定阻燃性和稳定的火灾循环报警响应。这项研究提供了一种新型绿色火灾预警纳米复合涂料,具有被动和主动相结合的火灾预警和防护功能。
Customized triphasic cartilage composite scaffold simulating hypoxic microenvironment for osteochondral regeneration
Chuan Guo, Zixuan Su, Lianghu Zhao, Renjin Chen, Yu Wang, Ye Wu, Haider Mohammed Khan, Walter Munesu Chirume, Zhigang Zhou, Pin Feng, Yuheng Liu, Chen Fan, Canyu Gao, Changchun Zhou, Qingquan Kong, Yujiang Fan
doi:10.1016/j.compositesb.2023.111161
模拟缺氧微环境的定制三相软骨复合支架用于骨软骨再生
The regeneration of the osteochondral complex in situ presents a significant challenge. The inherent hypoxic microenvironment of cartilage plays a critical role in facilitating osteochondral repair. The successful regeneration of the osteochondral complex necessitates the utilization of materials and structures that closely mimic its composition. In this study, carboxymethyl chitosan (CCS), oxidized hyaluronic acid (OHA), and tannic acid (Ta) were employed to fabricate an injectable and self-healing hydrogel (Ta@gel). The incorporation of Ta within the hydrogel network enables preferential oxidation, thereby creating an anoxic microenvironment within the hydrogel. Bone marrow-derived mesenchymal stem cells (BMSCs) were encapsulated within microspheres composed of methacrylic anhydride gelatin (GelMA). These microspheres were subsequently loaded into a Ta@gel. The resulting bionic hydrogel composite was then combined with a three-dimensional (3D) printed hydroxyapatite (HAp) scaffold coated with poly-l-lysine (PLL). This combination resulted in the formation of a bionic three-layer composite structure (HAp@PLL + Ta@gel + GelMA@BMSCs) that closely resembles the complex composition and structure of natural osteochondral complex. The efficacy of this customized triphasic composite scaffold in promoting osteochondral complex regeneration has been demonstrated in vitro and in vivo. Consequently, this study provided a new sight for inducing the in situ regeneration of cartilage.
骨软骨复合体的原位再生是一项重大挑战。软骨固有的缺氧微环境在促进骨软骨修复方面起着至关重要的作用。要想成功实现骨软骨复合体的再生,就必须使用能密切模拟其成分的材料和结构。在这项研究中,羧甲基壳聚糖(CCS)、氧化透明质酸(OHA)和单宁酸(Ta)被用来制造一种可注射的自愈合水凝胶(Ta@gel)。在水凝胶网络中加入钽可实现优先氧化,从而在水凝胶中形成缺氧微环境。骨髓间充质干细胞(BMSCs)被包裹在由甲基丙烯酸酐明胶(GelMA)组成的微球中。随后将这些微球装入 Ta@ 凝胶中。然后,将生成的仿生水凝胶复合材料与涂有聚赖氨酸(PLL)的三维(3D)打印羟基磷灰石(HAp)支架相结合。这种组合形成了仿生三层复合结构(HAp@PLL + Ta@gel + GelMA@BMSCs),与天然骨软骨复合体的复杂成分和结构非常相似。这种定制的三相复合支架在促进骨软骨复合体再生方面的功效已在体外和体内得到证实。因此,这项研究为诱导软骨的原位再生提供了新的视角。
Large-scale production of boron nitride nanosheets for flexible thermal interface materials with highly thermally conductive and low dielectric constant
Xiangdong Kong, Yapeng Chen, Rongjie Yang, Yandong Wang, Zhenbang Zhang, Maohua Li, Hanxi Chen, Linhong Li, Ping Gong, Jianxiang Zhang, Kang Xu, Yong Cao, Tao Cai, Qingwei Yan, Wen Dai, Xinfeng Wu, Cheng-Te Lin, Kazuhito Nishimura, Zhongbin Pan, Nan Jiang, Jinhong Yu
doi:10.1016/j.compositesb.2023.111164
大规模生产具有高导热性和低介电常数的柔性热界面材料氮化硼纳米薄片
As the operating power of electronic devices used in 5G technology continues to rapidly progress, demand is increasing for thermal conductive composites with exceptional dielectric insulating properties. Boron nitride nanosheets (BNNS)-based composites have garnered significant attention owing to the extraordinary inherent thermal conductivity and excellent dielectric insulation of BNNS. However, a bottleneck of mass exfoliation high-quality BNNS severely delays the advancement of BNNS-based composites. Herein, the large-scale production BNNS are attained through novel exfoliation method by rationally introducing vigorous ultrasonication treatment with an ultra-high power up to 1200 W. By acquiring approximately 32 g of high-quality BNNS in 5 cycles, the yield can be increased to around 40 %. The multilevel casting strategy prepared polydimethylsiloxane PDMS/BNNS composite exhibits a significantly enhanced κ⊥ of achieve to 3.82 W m−1 K−1 at 50 wt % of BNNS loading along with a low interfacial thermal resistance of 38 K mm2 W−1 and dielectric constant below 3. This finding provides a promising path for the massively producing high-quality BNNS and thermal interface materials to enhance thermal transport from electronics to heat sink.
随着用于 5G 技术的电子设备的工作功率不断快速提高,对具有优异介电绝缘性能的导热复合材料的需求也在不断增加。基于氮化硼纳米片(BNNS)的复合材料因其非凡的固有热导率和优异的介电绝缘性能而备受关注。然而,高质量 BNNS 的大规模剥离瓶颈严重阻碍了 BNNS 基复合材料的发展。在此,通过合理引入高达 1200 W 的超高功率剧烈超声处理,采用新颖的剥离方法实现了 BNNS 的大规模生产。多层次浇铸策略制备的聚二甲基硅氧烷 PDMS/BNNS 复合材料在 BNNS 含量为 50 wt % 时,κ⊥ 显著增强,达到 3.82 W m-1 K-1,同时界面热阻低至 38 K mm2 W-1,介电常数低于 3。
In-situ manipulation of TiB whisker orientation and investigation of its high-temperature mechanical properties in titanium matrix composites
Qiang Wang, Zhao-Hui Zhang, Luo-Jin Liu, Xiao-Tong Jia, Yang-Yu He, Xian-Yu Li, Xing-Wang Cheng
doi:10.1016/j.compositesb.2023.111165
钛基复合材料中 TiB 晶须取向的原位控制及其高温力学性能研究
“SPS pre-sintering + SPS reactive hot extrusion” (SPSHE) is a promising technique for manipulating the orientation of TiB whiskers (TiBw) in discontinuously reinforced titanium matrix composites (DRTMCs). In the current study, (12.4 vol % TiBw +2.9 vol % TiC)/Ti6Al4V composites were prepared using SPSHE technology, successfully achieving both the normalization of TiBw orientation and a high aspect ratio. Specifically, the [010] axis of TiBw was aligned with the extrusion direction, and the average aspect ratio was 24.86. Tensile tests were conducted on the DRTMC samples at temperatures of 873 K, 923 K, and 973 K. The results demonstrate that SPSHE significantly enhances the high-temperature strength of the composite. At 873 K, the DRTMC exhibited an exceptionally high tensile strength of 732.2 ± 20 MPa. The main strengthening mechanisms of the DRTMC include load transfer strengthening from TiBw and TiC particles, solution strengthening, fine grain strengthening and dislocation strengthening. Moreover, at 873 K and 923 K, the dominant failure mode of the reinforcement was a load-bearing fracture. However, as the test temperature increased to 973 K, a mixed failure mode of load-bearing fracture and interface debonding was observed in the reinforcement.
"SPS预烧结+SPS反应热挤压"(SPSHE)是操纵非连续增强钛基复合材料(DRTMC)中TiB晶须(TiBw)取向的一种很有前途的技术。本研究利用 SPSHE 技术制备了(12.4 vol % TiBw +2.9 vol % TiC)/Ti6Al4V 复合材料,成功实现了 TiBw 取向的正常化和高纵横比。具体来说,TiBw 的 [010] 轴与挤压方向一致,平均纵横比为 24.86。在 873 K、923 K 和 973 K 温度下对 DRTMC 样品进行了拉伸试验。在 873 K 时,DRTMC 的拉伸强度高达 732.2 ± 20 MPa。DRTMC 的主要强化机制包括 TiBw 和 TiC 颗粒的载荷传递强化、溶液强化、细晶粒强化和位错强化。此外,在 873 K 和 923 K 时,加固材料的主要破坏模式是承载断裂。然而,当试验温度升高到 973 K 时,在加固材料中观察到了承载断裂和界面脱粘的混合破坏模式。
Experimental and theoretical study on the electromagnetic shielding performance of polymer nanocomposites consisting of basalt fiber and CNTs
Ze-Xin Chen, Chao Chang, Xiu Yue, Hui Li, Cun-Guang Liang, Peng-Cheng Ma
doi:10.1016/j.compscitech.2023.110399
玄武岩纤维和碳纳米管聚合物纳米复合材料电磁屏蔽性能的实验和理论研究
In this paper, we substantiated the mechanism behind the absorption and multiple reflection shielding in the nanocomposites (2 mm in thickness) consisting of basalt fiber loaded with carbon nanotubes and polydimethylsiloxane when exposed to the X-band frequency (8.2–12.4 GHz). The experimental results confirmed that the interface polarization, capacitor-like structure, together with internal conducting networks contributed to the electromagnetic shielding effect in the material. Furthermore, calculation and simulation were employed to analyze the propagation of electromagnetic wave within the nanocomposites, giving direct evidence that the electromagnetic irradiation could be efficiently absorbed while the reflection loss played a marginal role in this process. The findings of this study shed light on the structural design and optimization of the nanocomposites for high-efficiency electromagnetic shielding.
在本文中,我们证实了由含碳纳米管和聚二甲基硅氧烷的玄武岩纤维组成的纳米复合材料(厚度为 2 毫米)在 X 波段频率(8.2-12.4 GHz)下产生吸收和多重反射屏蔽的机理。实验结果证实,界面极化、类似电容器的结构以及内部导电网络共同促成了材料的电磁屏蔽效应。此外,通过计算和仿真分析了电磁波在纳米复合材料内部的传播,直接证明了电磁辐照可被有效吸收,而反射损耗在此过程中的作用微乎其微。该研究结果为高效电磁屏蔽纳米复合材料的结构设计和优化提供了启示。
Adjustable Ti2C3Alx-based segregated composite network for enhanced electromagnetic shielding and fire safety
Wei Wang, Haowen Sun, Yuan Liu, Qi Wang
doi:10.1016/j.compscitech.2023.110400
基于 Ti2C3Alx 的可调节分隔复合网络,用于增强电磁屏蔽和防火安全
With the rapid development of communication technology and portable electronic devices, the demand for the design of electronic devices with superior electromagnetic interference shielding and fire safety performance is increasing. Herein, epoxy resins (EPs) with typical segregated networks were designed by emulsion polymerization and adhesion self-assembly strategies and novel polyphosphonitrile microspheres (PZS) synthesized by precipitation polymerization were used to improve the fire safety of EP composites. It is worth noting that the oil-water (EP to water) ratio in emulsion polymerization is closely related to the microscopic morphology of the segregated network. A smaller ratio of EP to water results in more paths for electrical charge transfer through the EP composites. As a result, EP/PT-3 with a minimum oil-to-water ratio exhibits a high EMI SE (electromagnetic interference shielding effectiveness) in the X-band ranging from 40.12 to 40.30 dB at a loading of 7.20 vol% Ti3C2Alx. Besides, the synergistic action of the adjustable Ti3C2Alx network with PZS endows EP superior flame retardant performance. Compared with EP, the PHRR and THR values of EP/PT-3 are down 55.7 % and 72.6 %, respectively. There is no doubt that EP/PT-3 has provided a new route for the preparation of Ti3C2Alx-based electromagnetic shielding and fireproof materials.
随着通信技术和便携式电子设备的快速发展,人们对设计具有优异电磁干扰屏蔽和防火安全性能的电子设备的要求越来越高。本文通过乳液聚合和粘附自组装策略设计了具有典型离析网络的环氧树脂(EP),并利用沉淀聚合合成的新型聚磷腈微球(PZS)提高了 EP 复合材料的防火安全性。值得注意的是,乳液聚合中的油水(EP 与水)比与离析网络的微观形态密切相关。EP 与水的比例越小,通过 EP 复合材料的电荷转移路径就越多。因此,油水比最小的 EP/PT-3 在装载 7.20 vol% Ti3C2Alx 时,在 X 波段表现出较高的 EMI SE(电磁干扰屏蔽效果),范围在 40.12 至 40.30 dB 之间。此外,可调节的 Ti3C2Alx 网络与 PZS 的协同作用赋予 EP 优异的阻燃性能。与 EP 相比,EP/PT-3 的 PHRR 和 THR 值分别下降了 55.7% 和 72.6%。毫无疑问,EP/PT-3 为制备基于 Ti3C2Alx 的电磁屏蔽和防火材料提供了一条新的途径。
Fabrication of robust superhydrophobic surface on silicone rubber
Lie Chen, Gongqi Huang, Tao Hu, Qianliang Li, Jian Cheng, Dun Liu
doi:10.1016/j.compscitech.2023.110401
在硅橡胶上制作坚固的超疏水表面
Robust superhydrophobic surfaces with periodic array structures composed of circular silica islands on silicone rubber substrates were fabricated using a combination of multi-laser exposure and chemical modification. Abrasion tests with sandpaper demonstrate that hard silica regions on the surface can protect the silicone rubber region from external damage, resulting in long-lasting superhydrophobicity. Moreover, with an increase in area fraction and a decrease in array hole radius, the wear of the filled superhydrophobic silica is slowed while the protection for the silicone rubber region is enhanced. Particularly, the optimum surface geometry had an area fraction of 35 % and array hole radius of 100 μm retaining its hydrophobicity up to 63 times of abrasion, eight times more than that of the superhydrophobic surface processed by lasers alone. The results of a sand impact test confirmed the resulting surface's resilience in an aeolian sand environment. This research demonstrated the feasibility of producing robust, superhydrophobic surfaces on flexible silicone rubber substrates and providing a foundation for improving and innovating related products.
利用多激光曝光和化学修饰相结合的方法,在硅橡胶基底上制造出了由圆形二氧化硅岛组成的周期性阵列结构的坚固超疏水表面。用砂纸进行的磨损测试表明,表面上坚硬的二氧化硅区域可以保护硅橡胶区域免受外部损伤,从而获得持久的超疏水性能。此外,随着面积分数的增加和阵列孔半径的减小,填充超疏水二氧化硅的磨损速度减慢,而对硅橡胶区域的保护作用增强。特别是,面积分数为 35 %、阵列孔半径为 100 μm 的最佳表面几何形状在 63 次磨损后仍能保持疏水性,是仅用激光加工的超疏水性表面的八倍。沙粒撞击测试结果证实了所产生的表面在风沙环境中的弹性。这项研究证明了在柔性硅橡胶基材上制作坚固的超疏水表面的可行性,并为改进和创新相关产品奠定了基础。