今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 4 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Analytical modeling and 3D printing of locally resonant composite sandwich metamaterials with inertial amplification mechanisms
Mizukami Koichi, Abe Kentaro, Senga Takehito, Ogi Keiji
doi:10.1016/j.compstruct.2023.117626
具有惯性放大机制的局部共振复合夹层超材料的解析建模与3D打印
In this paper, a locally resonant sandwich metamaterial beam with inertial amplification mechanisms is presented for flexural vibration attenuation. This sandwich metamaterial is proposed as a lightweight structure with a low-frequency stopband. An analytical model was developed to derive the equations of motion for the resonator core and skin plate using Hamilton’s principle. Analytical solutions for the stopband boundary frequencies were derived from the equations of motion. The analytical solutions demonstrated that inertial amplification resonators can exhibit lower resonance frequencies than linear spring-mass resonators with the same weight and spring constant. It was also shown that the proposed sandwich beam exhibited a lower frequency stopband in exchange for the stopband width. Finite element method analyses and experiments were performed to investigate the frequency response of the sandwich beam. The flexural vibration of the sandwich beam was significantly attenuated within a certain frequency range. The frequency range with low transmissibility agreed well with the stopband predicted by the analytical solutions.
本文提出了一种具有惯性放大机构的局部共振夹层超材料梁,用于弯曲振动的衰减。这种夹层超材料是一种具有低频阻带的轻质结构。利用哈密顿原理建立了一个解析模型,推导了谐振器芯和蒙皮板的运动方程。由运动方程导出了阻带边界频率的解析解。解析解表明,在相同重量和弹簧常数下,惯性放大谐振器比线性弹簧-质量谐振器具有更低的谐振频率。研究还表明,该夹层梁具有较低的频率阻带,以换取阻带宽度。对夹层梁的频率响应进行了有限元分析和实验研究。夹层梁的弯曲振动在一定频率范围内得到明显衰减。低透射率的频率范围与解析解预测的阻带吻合较好。
Shear strength determining mechanism of a b 45 laminate under tensile loading
Hong Chaeyoung, Lee Sooyoung, Ji Wooseok
doi:10.1016/j.compstruct.2023.117627
拉伸载荷作用下ab45层板抗剪强度的决定机理
The shear strength of a composite material is determined as a result of a complex damage and failure process, but the detailed progression has not been clearly elucidated. Here, the mechanism of determining the strength of a ± 45 laminate under tensile loading is revealed from exquisitely designed experiments in conjunction with high-fidelity numerical simulation. Synchrotron radiation computed tomography is employed for extremely high-resolution images of damage status inside the composite just before its catastrophic failure. The ex situ observations discover the unique and consistent failure progression; one major matrix crack is initiated either in the + 45 or − 45 layer and delamination follows after the initial crack completely grows along both the fiber and transverse directions. After the delamination failure is triggered, remaining intact layers start to fail with multiple transverse matrix cracks. The failure of the intact layers is represented as a load drop in the global stress–strain curve. This sequential and interactive failure progression determines the shear strength of the ± 45 laminate. The numerical analysis finds that the location of the initial matrix crack is dependent on the microstructure. Once the matrix crack is initiated, the numerical simulation exactly reproduces the experimentally observed failure process.
复合材料的抗剪强度是一个复杂的损伤和破坏过程的结果,但详细的进展尚未清楚阐明。本文通过精心设计的实验,结合高保真数值模拟,揭示了 ± 45层合板在拉伸载荷下强度的决定机制。同步辐射计算机断层扫描被用于在复合材料灾难性失效之前对其内部损伤状态进行极高分辨率的成像。非原位观察发现了独特而一致的破坏过程;在 + 45或 − 45层中产生一个主要的基体裂纹,在初始裂纹沿纤维和横向完全扩展后发生分层。触发脱层破坏后,剩余的完整层开始破坏,形成多个横向基体裂纹。完整层的破坏表现为整体应力-应变曲线上的荷载下降。这种顺序和相互作用的破坏进程决定了 ± 45层压板的抗剪强度。数值分析发现,初始基体裂纹的位置与微观组织有关。一旦基体裂纹开始,数值模拟准确地再现了实验观察到的破坏过程。
An iso-contour method for automated fiber placement optimization of composite structures
Arsenyeva Anna, Duddeck Fabian, Thompson Harvey M.
doi:10.1016/j.compstruct.2023.117628
复合材料结构纤维自动铺放优化的等轮廓法
A new method for numerical optimization of fiber-steered composites is presented, which allows to control efficiently and effectively the curvature of the fibers of single- or multi-layer composite structures. It is based on the introduction of an artifical surface defined and controlled by a relatively small number of control points, which is optimized to identify optimal fiber orientations varying smoothly over the panels. Curvature constraints like the maximum fiber curvature constraint, MFCC, or the average fiber curvature constraint, AFCC, are respected explicitly by the method to ensure manufacturability of the composite component. Three validation cases are regarded where results of the unconstrained case are compared to those of established methods to illustrate the validity of the new approach. They are complemented by results considering curvature constraints showing that optimal structures depend strongly on the chosen curvature thresholds. Finally, a rib optimization of a wingbox structure is realized as a more complex case.
提出了一种新的纤维导向复合材料的数值优化方法,可以有效地控制单层或多层复合材料结构中纤维的曲率。它基于引入由相对较少数量的控制点定义和控制的人造表面,该表面经过优化以确定在面板上平滑变化的最佳纤维方向。该方法明确考虑了曲率约束,如最大纤维曲率约束(MFCC)或平均纤维曲率约束(AFCC),以确保复合材料部件的可制造性。通过三个验证案例,将无约束情况下的结果与已有方法的结果进行了比较,以说明新方法的有效性。考虑曲率约束的结果表明,最优结构强烈依赖于所选择的曲率阈值。最后,以更为复杂的翼箱结构为例,实现肋部优化。
In-situ micro-CT damage analysis of carbon and carbon/ glass hybrid laminates under tensile loading by image reconstruction and DVC technology
Jiang Lanxin, Xiong Hongzi, Zeng Tao, Wang Jie, Xiao Shoune, Yang Long
doi:10.1016/j.compositesa.2023.107844
基于图像重建和DVC技术的碳和碳/玻璃复合层合板拉伸载荷原位微ct损伤分析
Carbon/ glass fibre-reinforced plastic (C/GFRP) offers advantages in engineering applications due to its low cost. However, the mechanism underlying the evolution of damage in C/GFRP under tension remains unclear. Advanced in-situ micro X-ray computed tomography (µCT) is a useful method for investigating the damage evolution of fibre composites. In this study, two tensile specimens, carbon fibre reinforced plastic (CFRP) and C/GFRP, were prepared, and in-situ µCT scanning was performed at different points during the tensile process. To quantify the voids, examine the fracture morphology, and investigate the void volume fractions, three-dimensional (3D) models were constructed while employing an image reconstruction algorithm. Finally, digital volume correlation (DVC) was employed to study the 3D strain fields. The results suggest that C/GFRP exhibits a higher initial void volume ratio and a faster rate of damage evolution. The 3D strain field and stress concentration area can be used to predict the precise location where the specimen would fracture.
碳/玻璃纤维增强塑料(C/GFRP)由于其低成本而在工程应用中具有优势。然而,C/GFRP在张力作用下损伤演变的机制尚不清楚。先进的原位微x射线计算机断层扫描(µCT)是研究纤维复合材料损伤演化的有效方法。本研究制备了碳纤维增强塑料(CFRP)和C/GFRP两种拉伸试样,并在拉伸过程的不同时刻进行原位微CT扫描。为了量化孔隙,检查裂缝形态,并研究孔隙体积分数,在使用图像重建算法的同时构建了三维(3D)模型。最后,采用数字体积相关(DVC)技术对三维应变场进行了研究。结果表明,C/GFRP具有更高的初始空隙体积比和更快的损伤演化速率。三维应变场和应力集中区可以用来预测试样断裂的精确位置。
Effect of various weaving architectures on mechanical, vibration and acoustic behavior of Kevlar-Hemp intra-ply hybrid composites
Jeyaguru Sangilimuthukumar, Muthu Kumar Thiagamani Senthil, Siengchin Suchart, Subramanian Jeyanthi, Ebrahimnezhad-Khaljiri Hossein, Mavinkere Rangappa Sanjay, Khan Anish, Abuthakeer S Syath, S Rajesh
doi:10.1016/j.compositesa.2023.107845
不同织造结构对凯夫拉-大 麻复合材料力学、振动和声学性能的影响
Due to the benefits of including high stiffness, low density, low cost, ecologically benign nature and abundant availability, natural fibers are employed as reinforcement in composites. These fibers however have a few shortcomings, including poor moisture resistance and incompatibility with most matrices. Therefore, the goal of this research is to combine the benefits of natural fiber (hemp) with synthetic fiber (kevlar) to develop a hybrid composite. Hemp and Kevlar yarns were handloomed to form fabrics with different architectures such as plain, twill and basket. These hybrid fiber epoxy composites were fabricated using compression molding and the samples were subjected to mechanical testing, free vibration and acoustic emission characteristics. Hemp and Kevlar fiber composites were also fabricated for comparison purpose. The results revealed that the twill and basket weave intra ply hybrid composites exhibited the better mechanical properties when compared with the plain weave hybrids. Whereas, the free vibration results showed that the all the hybrids exhibited better performance that the mono-fiber composites. Acoustic behavior of the basket weave hybrid was found to have the highest sound transmission loss value of 13.7 dB in the higher frequency range. On the other hand, the hemp-epoxy composites exhibited the highest sound transmission level of 6.3 dB in the lower frequency range.
天然纤维具有高刚度、低密度、低成本、生态友好、可利用性丰富等优点,被广泛应用于复合材料的增强中。然而,这些纤维有一些缺点,包括抗湿性差和与大多数基质不相容。因此,本研究的目标是将天然纤维(大 麻)与合成纤维(凯夫拉尔)的优点结合起来,开发一种混合复合材料。大 麻和凯夫拉纱线被手工织造成不同结构的织物,如平纹、斜纹和篮纹。采用压缩成型的方法制备了复合材料,并对其进行了力学性能测试、自由振动和声发射特性测试。为了比较,还制备了大 麻纤维和凯夫拉纤维复合材料。结果表明,斜纹和篮织复合材料的力学性能优于平纹复合材料。而自由振动结果表明,混合纤维的性能均优于单纤维复合材料。在较高的频率范围内,篮织复合材料的声行为具有最高的传声损失值,为13.7 dB。另一方面,大 麻-环氧树脂复合材料在低频范围内的声透射率最高,为6.3 dB。
Ultrathin carbon layer coated MXene/PBO nanofiber films for high performance electromagnetic interference shielding and thermal stability
Gong Kaijie, Peng Yanmeng, Liu An, Qi Shuhua, Qiu Hua
doi:10.1016/j.compositesa.2023.107857
超薄碳层涂层的MXene/PBO纳米纤维薄膜具有高性能的电磁干扰屏蔽和热稳定性
In this study, a carbon layer coated MXene/poly(p-phenylene-2,6-benzobisoxazole) nanofibers (PNFs) (MXene/PNF@C) EMI shielding composite film was obtained through polymer infiltration and pyrolysis (PIP) technique. The introduction of the carbon layer improved both the electrical and thermal conductive pathways of the film leading to the enhancement of its electrical conductivity(σ), thermal conductivity coefficient (λ) and EMI shielding effectiveness (SE). Meanwhile, thermal annealing reduced the defects of PBO molecular chains and improved the mechanical properties of the composite film. When the content of MXene is 50 wt% and the thickness of the film is only 37 μm, MP50@C-400 composite film has the best comprehensive properties, with the σ, λ, specific EMI SE (SEt) and tensile strength is 1760 S/m, 5.64 W/(m·K), 1108.1 dB/mm and 66.8 MPa, respectively, and its weight loss is only 24.1% at 800°C. The composite film provides important application prospects in 5G communication technology, wearable equipment and artificial intelligence.
本研究采用聚合物渗透热解(PIP)技术制备了碳层包覆MXene/聚(对苯-2,6-苯并异恶唑)纳米纤维(MXene/PNF@C)电磁干扰屏蔽复合膜。碳层的引入改善了薄膜的导电和导热途径,从而提高了薄膜的电导率(σ)、导热系数(λ)和电磁干扰屏蔽效能(SE)。同时,热处理减少了PBO分子链的缺陷,提高了复合膜的力学性能。当MXene含量为50 wt%,薄膜厚度仅为37 μm时,MP50@C-400复合薄膜的综合性能最好,σ、λ、比EMI SE (SEt)和抗拉强度分别为1760 S/m、5.64 W/(m·K)、1108.1 dB/mm和66.8 MPa, 800℃时的失重率仅为24.1%。复合薄膜在5G通信技术、可穿戴设备、人工智能等方面具有重要的应用前景。
Facile in-situ synthesis of carbon black@poly(ionic liquid) composites with a smooth U-link chain macrostructure within surfactant-free ionic liquid microemulsions
Wang Aili, Ye Tingting, Liu Yuyang, Song Minxin, Lou Nan, Wu Guangshun, Niu Yuzhong, Zheng Tanghong
doi:10.1016/j.compositesa.2023.107859
无表面活性剂离子液体微乳液中具有光滑u链结构的碳black@poly(离子液体)复合材料的原位合成
Poly(ionic liquid)s show tremendous potential in the application of strain sensing. However, their development is limited by tedious fabrication techniques and the instability factor of existing poly(ionic liquid)s-based strain sensing materials. In this work, we in situ synthesized a novel carbon black and poly(ionic liquid) composites (CB@PILs) by performing thiol-ene click reaction within a surfactant-free ionic liquid microemulsion. The successful construction and reaction of the composites were confirmed by FTIR, XRD, XPS, SEM, TG/DSC, strain test, and conductivity analyses. Results demonstrated that a composite that has a smooth U-link chain macrostructure could be prepared by altering the carbon black content at 3 wt%, and the resultant polymer presented good thermal stability and strain sensing performance. The mass ratio between polyethylene glycol diacrylate and hydroxyethyl methacrylate could further improve the conductivity and mechanical properties of CB@PIL composites. This work provides a potential avenue for designing CB@PIL composites, thus making them viable for strain sensing.
聚离子液体在应变传感领域显示出巨大的应用潜力。然而,它们的发展受到繁琐的制造技术和现有的基于多离子液体的应变传感材料的不稳定性因素的限制。在这项工作中,我们通过在无表面活性剂的离子液体微乳液中进行巯基点击反应,原位合成了一种新型的炭黑和聚离子液体复合材料(CB@PILs)。通过FTIR, XRD, XPS, SEM, TG/DSC,应变测试和电导率分析证实了复合材料的成功构建和反应。结果表明,当炭黑含量为3 wt%时,可以制备出具有光滑u链宏观结构的复合材料,该聚合物具有良好的热稳定性和应变传感性能。聚乙二醇二丙烯酸酯与甲基丙烯酸羟乙酯的质量比可以进一步提高CB@PIL复合材料的电导率和力学性能。这项工作为设计CB@PIL复合材料提供了一条潜在的途径,从而使它们能够用于应变传感。
Bone-targeted engineered bacterial extracellular vesicles delivering miRNA to treat osteoporosis
Liu Han, Wu Yan, Wang Fuxiao, Wang Sicheng, Ji Ning, Wang Mingkai, Zhou Guangyin, Han Ruina, Liu Xinru, Weng Weizong, Tan Haoqi, Jing Yingying, Zhang Wencai, Zhang Hao, Shi Zhongmin, Su Jiacan
doi:10.1016/j.compositesb.2023.111047
骨靶向工程细菌细胞外囊泡递送miRNA治疗骨质疏松症
Osteoporosis (OP), characterized by decreased bone density and destruction of bone microstructure, is a common systemic bone disease in the elderly. Conventional therapies suffer from poor targeting and long-term toxicity. Engineered bacterial extracellular vesicles (BEVs) containing bioactive molecules show great potential as alternative OP therapies. Here, we developed a delivery system based on BEVs secreted probiotic Lactobacillus rhamnosus GG (LGG). Bone-targeting peptides were anchored on the LGG-EVs membranes, which endowed LGG-EVs the ability to deliver intrinsic miRNA to bone microenvironment. Bone-targeted LGG-EVs (BT-LGG-EVs) exhibited great bone targeting capability without significant toxicity. BT-LGG-EVs not only promoted osteogenic differentiation and mineralization but also inhibited the formation of osteoclasts. Furthermore, BT-LGG-EVs were demonstrated to be able to attenuate the OVX-induced osteoporotic phenotypes. Our study demonstrated that BT-LGG-EVs hold great promise for use as an innovative, safe, and effective solution for the treatment of OP.
骨质疏松症(Osteoporosis, OP)是一种常见的老年人全身性骨病,以骨密度降低和骨微结构破坏为特征。传统疗法存在靶向性差和长期毒性的问题。含有生物活性分子的工程细菌细胞外囊泡(BEVs)作为OP的替代疗法具有很大的潜力。在此,我们开发了一种基于bev分泌的益生菌鼠李糖乳杆菌GG (LGG)的递送系统。骨靶向肽被锚定在lgg - ev膜上,这赋予了lgg - ev向骨微环境传递内在miRNA的能力。骨靶向lgg - ev (bt - lgg - ev)表现出良好的骨靶向能力,且没有明显的毒性。bt - lgg - ev不仅能促进成骨分化和矿化,还能抑制破骨细胞的形成。此外,bt - lgg - ev被证明能够减轻ovx诱导的骨质疏松表型。我们的研究表明,bt - lgg - ev有望作为一种创新、安全、有效的治疗OP的解决方案。
An ultrasensitive flexible strain sensor based on CNC/CNTs/MXene/TPU fibrous mat for human motion, sound and visually personalized rehabilitation training monitoring
Cui Meijie, Wu Songkai, Li Jiannan, Zhao Yi, Zhai Wei, Dai Kun, Liu Chuntai, Shen Changyu
doi:10.1016/j.compscitech.2023.110309
一种基于CNC/CNTs/MXene/TPU纤维垫的超灵敏柔性应变传感器,用于人体运动、声音和视觉个性化康复训练监测
Personalized rehabilitation training provides maximum help to stroke patients to alleviate the after-effects and restore the body to normal function. However, available monitoring devices have the disadvantages of being large, requiring professional guidance, and lacking intuitive signal display capabilities. Herein, a bio-inspired wearable high-performance strain sensor with a simple structure can simultaneous electrical signals and optical visualization in response to external stimuli. The sensor comprises a conductive layer with significant electromechanical behaviors of cellulose nanocrystals (CNC)/carbon nanotubes (CNTs)/MXene nanohybrid network, and a stretchable elastomer layer consisting of thermoplastic polyurethane and fluorescent agent. Benefiting from the designed microcracks and fluorescent material, the strain sensor exhibits ultra-high sensitivity (476800), ultra-low detection limit (0.005%), low response time (60 ms), wide working range (0–100%), and enables strain visualization for applications in visually rehabilitation training monitoring. Based on these sensing characteristics, the sensor shows great advantages in human motion and sound monitoring, the integration of digital signals and visual images makes it show great potential in visually personalized rehabilitation training monitoring.
个性化康复训练为脑卒中患者减轻后遗症,恢复身体正常功能提供了最大的帮助。但是现有的监控设备存在体积大、需要专业人员指导、缺乏直观的信号显示能力等缺点。本文设计了一种结构简单的仿生可穿戴高性能应变传感器,该传感器可以响应外部刺 激同时发出电信号和光学可视化。该传感器包括具有显著机电行为的纤维素纳米晶体(CNC)/碳纳米管(CNTs)/MXene纳米混合网络导电层和由热塑性聚氨酯和荧光剂组成的可拉伸弹性体层。得益于所设计的微裂纹和荧光材料,该应变传感器具有超高灵敏度(476800)、超低检出限(0.005%)、低响应时间(60 ms)、宽工作范围(0-100%),可实现应变可视化,用于视觉康复训练监测。基于这些传感特性,传感器在人体运动和声音监测方面显示出巨大的优势,数字信号与视觉图像的融合使其在视觉个性化康复训练监测方面显示出巨大的潜力。