今日更新:Composite Structures 7 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 3 篇
Experimental and Numerical Analysis of the Microstructure and Mechanical Properties of Unidirectional Glass Fiber Reinforced Epoxy Composites
Seshaiah Turaka, Ravikiran Chintalapudi, Narayanan Kannaiyan Geetha, Bridjesh Pappula, Seshibe Makgato
doi:10.1016/j.compstruct.2024.117887
单向玻璃纤维增强环氧树脂复合材料微观结构和力学性能的实验与数值分析
Numerical modeling was done to predict the pattern and features of the fracture surface and to understand the mechanisms and cause of the failure. Various fiber orientations of 0°, 90°, 0°/90° and ±45° were utilized in the production of unidirectional glass-fiber-reinforced epoxy composites via the vacuum bagging technique. The mechanical properties of the manufactured composites were evaluated by measuring parameters including tensile strength, compressive strength, flexural strength and interlaminar shear strength. High-resolution scanning electron microscopy was employed to determine the mechanisms of fracture in laminates. The mechanical properties of the composite material were found to be considerably enhanced when a unidirectional 0° fiber orientation was employed, as compared to other fiber orientations. This was true for tensile, compressive, flexural and interlaminar shear loading modes. Depending on the direction of the fibers, the composite laminates showed different ways to break, such as fibers pulling away from the matrix, holes in the matrix, and river flow lines. The outcomes of the numerical simulation demonstrated a high level of concordance with experimental findings.
为预测断裂面的形态和特征以及了解断裂的机理和原因,进行了数值建模。通过真空袋技术,利用 0°、90°、0°/90° 和 ±45° 等不同纤维取向生产单向玻璃纤维增强环氧树脂复合材料。通过测量拉伸强度、压缩强度、弯曲强度和层间剪切强度等参数,对所制造复合材料的机械性能进行了评估。高分辨率扫描电子显微镜用于确定层压板的断裂机制。结果发现,与其他纤维取向相比,采用单向 0° 纤维取向时复合材料的机械性能大大提高。拉伸、压缩、弯曲和层间剪切加载模式都是如此。根据纤维方向的不同,复合材料层压板显示出不同的断裂方式,如纤维从基体中拉出、基体中出现孔洞以及河流流线。数值模拟结果与实验结果高度一致。
Experimental and Numerical Investigation on Bearing Behavior of Hybrid Thin/Thick-ply Composite Laminates
Mohamed Sahbi Loukil, Sergio Costa, Mats Bergwall, H.S. Deepthi Prasad, Florence Moreau, Mikael Segersäll, Zlatan Kapidzic, Robin Olsson
doi:10.1016/j.compstruct.2024.117888
薄层/厚层混合复合层压板承载行为的实验和数值研究
Experimental and numerical studies were carried out to characterize hybrid thin- and thick-ply composite laminates and assess modelling capabilities. Five different composite laminates were manufactured using a single material system with varying proportions of thin plies (0%, 50%, and 100% thin-ply). Bearing tests were performed and the results from the tests were investigated. The results showed that performance, in terms of bearing strength at onset of damage and ultimate bearing stress, increased proportionally with the increasing amount of thin plies within the laminate. Microscopic examination of the failure modes for all laminates was performed at the center of the hole to determine the dominant failure mode. The numerical investigation uses a highly detailed mesoscale model previously validated for crash simulations but never used successfully to bearing damage areas. The results showed a good correlation regarding both the load response and the morphology of damage.
为了确定薄层和厚层混合复合材料层压板的特性并评估建模能力,我们进行了实验和数值研究。使用单一材料系统制造了五种不同的复合材料层压板,薄层的比例各不相同(0%、50% 和 100% 薄层)。进行了承载试验,并对试验结果进行了研究。结果表明,随着层压板中薄层数量的增加,其性能(即开始损坏时的承载强度和极限承载应力)也成比例增加。在孔中心对所有层压板的失效模式进行了显微检查,以确定主要的失效模式。数值研究使用了一个高度详细的中尺度模型,该模型曾在碰撞模拟中得到验证,但从未成功用于承载损坏区域。结果表明,载荷响应和损坏形态之间具有良好的相关性。
A NEW C0 CONTINUOUS REFINED ZIGZAG {1,2} FINITE ELEMENT FORMULATION FOR FLEXURAL AND FREE VIBRATION ANALYSES OF LAMINATED COMPOSITE BEAMS
Batuhan Yurtsever, Yonca Bab, Akif Kutlu, Mehmet Dorduncu
doi:10.1016/j.compstruct.2024.117890
一种新的 C0 连续精炼之字形 {1,2}用于层状复合梁弯曲和自由振动分析的有限元配方
This study presents a novel C0 continuous refined zigzag finite element formulation {1,2}, namely RZE{1,2}, for the bending and free vibration analyses of laminated composite beams. The Refined Zigzag Theory (RZT) effectively combines accuracy and computational efficiency, making it a robust approach for thin and thick laminated composite structures. The RZT eliminates the need for shear correction factors, thereby enhancing the overall streamline of the analysis process. The present RZE{1,2} formulation takes into account the transverse stretching by introducing quadratic through-thickness variations of deflection components. The governing equations of the RZT are derived by means of Hamilton’s principle. The through-the-thickness variations of the transverse shear and normal stresses are calculated by integrating the stress equilibrium equations in a post-processing step. Therefore, the Peridynamic Least Squares Minimization (PDLSM) approach is utilized to obtain precise derivatives of axial stresses in the stress equilibrium equations. A new finite element formulation is built up with 3-nodes with a total of 15 DOF. In order to study the influence of transverse stretching, different types of boundary conditions and material variations are applied for laminated composite beams for the bending and free vibration analyses. The distribution of displacements as well as the axial and transverse stresses of the thick beams are extensively examined. The outcomes of RZT are in good agreement with the reference solutions in the literature. The findings of the present study reveal that the presence of the transverse stretching produces more realistic predictions for thick beams where the shear deformations are influential.
本研究针对层状复合梁的弯曲和自由振动分析,提出了一种新颖的 C0 连续精炼之字形有限元公式 {1,2},即 RZE{1,2} 。精制之字形理论(RZT)有效地结合了精度和计算效率,是一种适用于薄层和厚层复合材料结构的稳健方法。RZT 不需要剪切修正系数,从而提高了分析过程的整体流畅性。目前的 RZE{1,2} 公式通过引入挠度分量的二次穿透厚度变化来考虑横向拉伸。RZT 的控制方程是通过汉密尔顿原理推导出来的。横向剪应力和法向应力的厚度变化是通过后处理步骤中的应力平衡方程积分计算得出的。因此,利用周动力最小二乘法(PDLSM)来获得应力平衡方程中轴向应力的精确导数。新的有限元模型由 3 个节点组成,共有 15 个 DOF。为了研究横向拉伸的影响,在层压复合梁的弯曲和自由振动分析中应用了不同类型的边界条件和材料变化。对厚梁的位移分布以及轴向和横向应力进行了广泛研究。RZT 的结果与文献中的参考解十分吻合。本研究的结果表明,对于剪切变形影响较大的厚梁,横向拉伸的存在能产生更真实的预测结果。
NSM-CFRP Rods with varied embedment depths for strengthening RC T-beams in the negative moment region: Investigation on high cyclic response
Laurencius Nugroho, Yanuar Haryanto, Hsuan-Teh Hu, Ay Lie Han, Fu-Pei Hsiao, Chia-Chen Lin, Pu-Wen Weng, Endah Purwaningsih Widiastuti
doi:10.1016/j.compstruct.2024.117891
不同嵌入深度的 NSM-CFRP 杆件用于负弯矩区域的 RC T 型梁加固:高循环响应研究
Throughout its service life, structural reinforced concrete (RC) encounters cyclic loads and the load amplitude might always vary, leading to a mixed high and low-cycle failure. This research investigates the high cyclic response of RC T-beams strengthened in the negative moment region using near-surface mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) rods. The distinctive aspect lies in exploring varied embedment depths, including the introduction of half-embedded configurations as an alternative NSM technique. The study comprehensively analyzes load-carrying capacity, failure modes, energy dissipation, ductility, stiffness degradation, and strain behavior, providing insights into the effects of loading rates on structural response. Through an experimental program comparing fully-embedded (BF-D) and half-embedded (BH-D) CFRP rods with a control beam (BN-D) under high-rate cyclic loading, significant increases in ultimate load capacity (21.23% for BH-D and 30.86% for BF-D) are demonstrated despite debonding occurrences. The findings highlight a trade-off between benefits (enhanced ultimate load capacities, improved energy dissipation, and increased stiffness) and drawbacks (reduced ductility and tendencies toward brittle behavior) under high loading rates. Furthermore, a rate-dependent material formula is developed and validated, predicting the flexural strength of the negative moment region in good agreement with experimental results. Finally, this research contributes practical solutions to RC element strengthening challenges and advances understanding of NSM-CFRP-strengthened beam, emphasizing the impact of loading rates on structural response.
钢筋混凝土(RC)结构在其整个使用寿命期间都会遇到循环载荷,而且载荷振幅可能始终变化,从而导致高循环和低循环混合失效。本研究探讨了使用近表面安装(NSM)碳纤维增强聚合物(CFRP)杆件加固负弯矩区域 RC T 梁的高循环响应。其独特之处在于探索了不同的嵌入深度,包括引入半嵌入配置作为 NSM 的替代技术。研究全面分析了承载能力、失效模式、能量耗散、延展性、刚度退化和应变行为,深入探讨了加载速率对结构响应的影响。通过对全嵌入式(BF-D)和半嵌入式(BH-D)CFRP 杆件与控制梁(BN-D)在高速循环加载下的实验项目进行比较,尽管出现了脱粘现象,但极限承载能力仍显著提高(BH-D 为 21.23%,BF-D 为 30.86%)。研究结果突出表明,在高加载速率下,材料的优点(提高极限承载能力、改善能量消耗和增加刚度)与缺点(降低延展性和倾向于脆性行为)之间存在权衡。此外,还开发并验证了一种与速率相关的材料公式,该公式预测负弯矩区域的抗弯强度与实验结果非常吻合。最后,这项研究为 RC 单元加固难题提供了实用的解决方案,并加深了对 NSM-CFRP 加固梁的理解,强调了加载速率对结构响应的影响。
Field test of GFRP bar anti-floating anchor slurry-rock interface bonding performance
Xiaoyu Bai, Xiangmei Zhao, Nan Yan, Gan Sun, Dongshuai Hou, Junwei Liu
doi:10.1016/j.compstruct.2024.117893
GFRP 条形抗浮锚杆泥浆-岩石界面粘结性能现场测试
Based on fiber Bragg grating (FBG) sensing and monitoring technology, the slurry-rock interface bonding characteristics of glass fiber reinforced polymer (GFRP) anti-floating anchor and steel anti-floating anchor were investigated through the field pull-out destructive test of GFRP bars and steel anti-floating anchor. The differences in slurry-rock interface bonding properties between GFRP anti-floating anchor and steel anti-floating anchor were defined. In addition, the distribution law of shear stress and axial stress at the slurry-rock interface of the GFRP anti-floating anchor was revealed along the anchoring depth. The results showed that the axial stress at the slurry-rock interface of the GFRP anti-floating anchor is maximum at the hole opening and decreases as depth increases. The axial stress reduces to zero at the anchorage depth of about 2.4 m. The shear stress at the slurry-rock interface increases and then decreases. The slurry-rock interface bonding curve of the GFRP anti-floating anchor is approximately a straight line, while the slurry-rock interface bonding curve of the steel anti-floating anchor is a broken line with an obvious inflection point. Comparing different materials and types of anti-floating anchors indicate that the bond performance of steel anti-floating anchors is slightly higher than that of GFRP anti-floating anchors, and the bond strength of anti-floating anchors’ slurry-rock interface improves with the increase of anchor bar diameter. The synergistic effect among anchor bars, grout, and rock mass of the GFRP anti-floating anchor exceeds that of the steel anti-floating anchor. Using the finite element software ABAQUS to GFRP anti-floating anchor rod on rock interface bonding performance simulation, the simulation results was coincident with the test result.
基于光纤布拉格光栅(FBG)传感与监测技术,通过对玻璃纤维增强聚合物(GFRP)抗浮锚杆和钢制抗浮锚杆的现场拉拔破坏性试验,研究了玻璃纤维增强聚合物(GFRP)抗浮锚杆和钢制抗浮锚杆的岩浆-岩石界面粘结特性。明确了 GFRP 抗浮锚杆和钢质抗浮锚杆在浆岩界面粘结性能上的差异。此外,还揭示了 GFRP 抗浮锚杆浆岩界面剪应力和轴向应力沿锚固深度的分布规律。结果表明,GFRP 抗浮锚杆浆岩界面的轴向应力在孔口处最大,并随着深度的增加而减小。在锚固深度约为 2.4 米时,轴向应力减小为零。浆岩界面的剪应力先增大后减小。GFRP 抗浮锚杆的岩浆-岩石界面粘结曲线近似于一条直线,而钢制抗浮锚杆的岩浆-岩石界面粘结曲线是一条有明显拐点的折线。比较不同材料和类型的抗浮锚杆可知,钢制抗浮锚杆的粘结性能略高于 GFRP 抗浮锚杆,抗浮锚杆浆岩界面的粘结强度随锚杆直径的增加而提高。GFRP 抗浮锚杆的锚杆、注浆和岩体之间的协同效应超过了钢抗浮锚杆。利用有限元软件 ABAQUS 对 GFRP 抗浮锚杆对岩石界面的粘结性能进行了模拟,模拟结果与试验结果吻合。
In-plane and out-of-plane vibration analysis of laminated composite frames with warping effects
Ramazan-Ali Jafari-Talookolaei, Saman Sadripour, Paolo S. Valvo
doi:10.1016/j.compstruct.2024.117895
具有翘曲效应的层压复合材料框架的平面内和平面外振动分析
This paper addresses the free vibration analysis of a general planar frame structure, consisting of an assembly of laminated composite beam members. A mathematical model is established for the beams by introducing a novel displacement field, which encompasses the influence of shear deformation, rotary inertia, material coupling, warping phenomenon, as well as in-plane and out-of-plane deformations. By incorporating these various factors, a comprehensive representation of the beam's behavior is achieved. The continuity equations for displacements and rotations of two adjacent members are formulated to derive the equations for the entire frame structure. The assembled equations are solved using the Finite Element Method (FEM). The numerical results obtained are compared with existing results in the literature and new results from 3D models in ANSYS. The present results for torsional modes are closer to the ANSYS results than the results of previous studies. An extensive analysis is performed to investigate the impact of various parameters, including stacking sequence, frame angle, relative frame length, and anisotropy ratios, on the system response.
本文探讨了由层压复合梁构件组合而成的一般平面框架结构的自由振动分析。通过引入新的位移场,建立了梁的数学模型,其中包括剪切变形、旋转惯性、材料耦合、翘曲现象以及平面内和平面外变形的影响。通过纳入这些不同的因素,实现了对梁行为的全面表述。通过计算相邻两个构件的位移和旋转的连续性方程,可以推导出整个框架结构的方程。使用有限元法(FEM)求解组合方程。获得的数值结果与文献中的现有结果以及 ANSYS 三维模型的新结果进行了比较。与之前的研究结果相比,目前的扭转模式结果更接近 ANSYS 的结果。通过大量分析,研究了各种参数(包括堆叠顺序、框架角度、相对框架长度和各向异性比)对系统响应的影响。
Mechanical analysis of new-type arc-cone anchor for CFRP strand wires
Rong-Gui Liu, Zheng-Nan Jing, Gui-Hua Xie, Ying Li
doi:10.1016/j.compstruct.2024.117896
用于 CFRP 钢绞线的新型弧锥锚的力学分析
Conventional anchors tend to produce ‘notch-effect’ at the tensile end due to stress concentration when anchoring prestressed CFRP strand cables. A new-type arc-cone anchor was designed with the purpose of optimizing the stress distribution in the anchor zone in this study. The ‘arc-cone’ model was proposed to represent the mechanical characteristics of the anchor, and the numerical simulation and experiments were carried out. The effect of the design factors on the anchoring performance was discussed, involving the arc-cone radius, the anchoring length, and the end hole wall thickness. The failure mode, the ultimate load, the anchoring efficiency coefficient as well as the stress distribution were ascertained with the consideration of the effect of the abovementioned design factors. The research results show that the extrusion stress on the barrel decreases with respect to both the wall thickness and the anchor length. The larger the radius of the arc-cone is, the larger the slip of the CFRP strand wire is. The proposed anchor configuration inversely changes the stress distribution from the tensile end to the free end, alleviates the ‘notch effect’ existing in the anchoring zone of conventional anchors, and consequently, improves the anchoring efficiency for CFRP strand wires.
传统的锚具在锚固预应力 CFRP 钢绞线时,由于应力集中,往往会在拉伸端产生 "缺口效应"。本研究设计了一种新型弧锥锚,旨在优化锚区的应力分布。提出了 "弧锥 "模型来表示锚的力学特性,并进行了数值模拟和实验。讨论了弧锥半径、锚固长度和端孔壁厚等设计因素对锚固性能的影响。考虑到上述设计因素的影响,确定了破坏模式、极限载荷、锚固效率系数以及应力分布。研究结果表明,筒体上的挤压应力随壁厚和锚固长度的增加而减小。弧锥半径越大,CFRP 钢绞线的滑移越大。所提出的锚固结构反向改变了从拉伸端到自由端的应力分布,缓解了传统锚固器锚固区存在的 "缺口效应",从而提高了 CFRP 钢绞线的锚固效率。
MXenes-based nanojunction with defective MoSe2 nanocatalyst towards reducing the thermal runaway hazard of polymer
Junling Wang, Keji Li, Chao Cheng, Shibin Nie, Wei Cai, Qi Zhang, Fudong Zhao, YUEN Kwok Kit Richard
doi:10.1016/j.compositesa.2024.108004
基于有缺陷 MoSe2 纳米催化剂的 MXenes 纳米结降低聚合物的热失控危害
The shining star of transition metal carbides (MXenes, denoted as MX) has motivated the great interest in flame retardation. Meanwhile, its usage suffers from the issues of poor flame-retardant effectiveness, serious aggregation, etc. Here, the interfacial assembly method is employed to deploy the MX based nanojunction with defective MoSe2 nanocatalyst (MX-Mo-A). Under its extremely-low dosage (∼1.0 wt%), the decreases of 41.0%, 57.0%, 29.2% on peak heat release rate, peak smoke production rate, total smoke production of thermoplastic polyurethane are achieved, confirming the greatly hindered emissions of heat and smoke. Besides, the peak CO yield is impaired by 81.2%, demonstrating the obviously impeded fire toxicity. Such flame retardance superiorities are vividly elucidated via contrast with published works. More encouragingly, the markedly suppressed releases of toxic aromatic compounds, NO and HCN are detected. This work may enable the new paradigm for designing interfacial assembly induced nanojunctions and fabricating fire-proof polymer-matrix composites (PMCs).
过渡金属碳化物(MXenes,简称 MX)这颗耀眼的明星激发了人们对阻燃的极大兴趣。与此同时,它的使用也存在阻燃效果差、聚集严重等问题。在此,我们采用界面组装方法,将 MX 与有缺陷的 MoSe2 纳米催化剂(MX-Mo-A)形成纳米结。在极低的用量(1.0 wt%)下,热塑性聚氨酯的峰值放热率、峰值产烟率和总产烟量分别下降了 41.0%、57.0% 和 29.2%,热量和烟雾的排放受到了极大的阻碍。此外,一氧化碳的峰值产率降低了 81.2%,表明火灾毒性明显减弱。通过与已发表作品的对比,这些阻燃优势得到了生动的阐释。更令人鼓舞的是,还检测到有毒芳香族化合物、NO 和 HCN 的释放明显受到抑制。这项研究为设计界面组装诱导纳米结和制造防火聚合物基复合材料(PMC)提供了新的范例。
Multi-stage releasing water: The unique decomposition property makes attapulgite function as an unexpected clay minral-based gas source in intumescent flame retardant
Zeyang Gao, Bihe Yuan, Congrui Qi, Junfan Liu, Yu Zhu, Shusheng Wu, Pengcheng Wang, Yue Kong, Hang Jin, Bin Mu
doi:10.1016/j.compositesa.2024.108014
多级释放水:独特的分解特性使凹凸棒石成为膨胀型阻燃剂中意想不到的粘土矿基气体源
During extensive research on intumescent flame retardants, the gas source has primarily focused on nitrogenated compounds releasing toxic gases like ammonia. This investigation revealed that attapulgite (ATP) possesses the ability to form an intumescent char layer with remarkable height within polymers. To elucidate its flame-retardant and char-expansion mechanisms, a comprehensive study was conducted. The investigation unveiled that ATP possesses a unique decomposition characteristic of multi-stage water release, distinguishing it from halloysite, montmorillonite, and kaolinite. Furthermore, ATP exhibits the capability of migrating and facilitating the formation of a char layer. Consequently, an expanded char layer is formed through ATP’s dual effects on both gas and condensed phases. Additionally, acid modification enhances its dispersibility within the composite, thereby providing better support to its char layer. This pioneering research establishes the connection between ATP and its role as a gas source, offering innovative insights into applications of ATP in gas-phase flame retardancy.
在对膨胀型阻燃剂的广泛研究中,气体来源主要集中在释放氨等有毒气体的含氮化合物上。这项研究发现,阿塔蓬石(ATP)具有在聚合物中形成具有显著高度的膨胀炭层的能力。为了阐明其阻燃性和炭扩展机制,进行了一项综合研究。研究发现,ATP 具有多级释水的独特分解特性,有别于埃洛石、蒙脱石和高岭石。此外,ATP 还具有迁移和促进炭层形成的能力。因此,通过 ATP 对气相和凝结相的双重作用,形成了一个扩展的炭层。此外,酸改性还能提高其在复合材料中的分散性,从而为其炭层提供更好的支撑。这项开创性的研究建立了 ATP 与其作为气源的作用之间的联系,为 ATP 在气相阻燃领域的应用提供了创新性的见解。
Strengthening and Toughing Design of Graphene Oxide Based Artificial Nacre Composites Regulated by Dimensional Hierarchy of Ternary Structure
Yongcun Li, Zhen Wen, Yunbo Luan, Dawei Sun, Jinglei Yang
doi:10.1016/j.compositesa.2024.108015
三元结构尺寸层次调控氧化石墨烯基人造珍珠质复合材料的强度和韧性设计
The strength and toughness of materials are predominantly attributed to the structure-related stress distribution and energy dissipation in the deformation and damage process. Inspired by the hierarchical structure of nacre, the ternary structure artificial nacre composite films composed of homophonous dimensional hierarchy graphene oxide (GO) sheets and polyvinyl alcohol (PVA) were designed and prepared via the dry-spinning process. It demonstrates that there is a mechanical synergistic effect of the dimensional hierarchy GO sheets that can improve the stress distribution (suppress and disperse the local stress concentration regions) and increase the energy dissipation (trigger more crack deflection), thus improving the toughness on the premise of ensuring excellent strength of the films. Based on the dry-spinning and lamination assembly process, large-size bulk composites with excellent mechanical properties constructed by these films can be obtained and are expected to achieve mass production, which has great potential applications in aerospace, automobile, biomedical, and energyindustries.
材料的强度和韧性主要归因于变形和损伤过程中与结构相关的应力分布和能量耗散。受珍珠质分层结构的启发,设计并通过干法纺丝工艺制备了由同构分层氧化石墨烯(GO)片和聚乙烯醇(PVA)组成的三元结构人工珍珠质复合薄膜。结果表明:同维分层氧化石墨烯(GO)片材具有力学协同效应,可改善应力分布(抑制和分散局部应力集中区域),增加能量耗散(引发更多裂纹偏转),从而在保证薄膜优异强度的前提下提高其韧性。基于干法纺丝和层压组装工艺,由这些薄膜构建的具有优异力学性能的大尺寸块状复合材料可望实现批量生产,在航空航天、汽车、生物医学和能源等行业具有巨大的应用潜力。
The influence of drilling-induced damages and hole quality on hoop tensile and fatigue behavior of CFRP tubes
Sezer Morkavuk, Kubilay Aslantaş, Lokman Gemi, Uğur Köklü, Şakir Yazman
doi:10.1016/j.compositesa.2024.108005
钻孔引起的损伤和孔的质量对 CFRP 管的环向拉伸和疲劳行为的影响
Filament winding and roll wrapping methods are widely used in the production of composite tubes. While the mechanical behavior of composites produced by different methods may be different, the effects of the damages that occurred while machining composite tubes on the mechanical behavior may also be different. In this study, the effects of drilling-induced damages and hole quality on the tensile and fatigue strength of the filament-wound and roll-wrapped composite tubes were experimentally investigated. Results showed that while the behavior of the filament-wound composite tube under hoop tensile load is better than the roll-wrapped composite tube, the roll-wrapped tube performs better than filament-wound tube under hoop fatigue load. It was also observed that different drilling conditions affect the mechanical behavior of filament-wound tube while it was found that drilling conditions do not have a significant effect on the mechanical behavior of roll-wrapped tube because manufacturing defects are more dominant.
缠丝法和辊包法被广泛用于复合材料管的生产。不同方法生产的复合材料的力学性能可能不同,而加工复合材料管时产生的损伤对其力学性能的影响也可能不同。本研究通过实验研究了钻孔引起的损伤和孔的质量对丝状缠绕复合管和辊式缠绕复合管的拉伸强度和疲劳强度的影响。结果表明,丝绕复合管在环向拉伸载荷下的性能优于辊绕复合管,而辊绕复合管在环向疲劳载荷下的性能优于丝绕复合管。研究还发现,不同的钻孔条件会影响丝绕复合管的机械性能,而钻孔条件对卷包复合管的机械性能影响不大,因为制造缺陷是主要原因。
Biomimetic and Environmentally Friendly Self-Assembly Behavior of Melamine onto the Surface of Black Phosphorus Nanosheets: Constructing Advanced P/N-Containing Nano Flame Retardants
Wei Cai, Weiyi Xing, Tianyang Cui, Junling Wang, Bicheng Lin, Zhaoxin Li, Liangyuan Qi, Xin Hu, Yang Ming, Peng Xiao, Fuli Bian, Bin Fei, Yuan Hu
doi:10.1016/j.compositesa.2024.108006
三聚氰胺在黑磷纳米片表面的仿生和环保自组装行为:构建先进的含 P/N 纳米阻燃剂
Herein, inspired by the hierarchical structure within the biological protein, we adjust the temperature of the aqueous solution to control the unfolding and reconstitution of hydrogen bonds among melamine (MA) molecules, thus preparing MA-functionalized black phosphorus (MA@BP) nanosheets. As confirmed by the first-principles calculations, melamine can spontaneously adsorb onto the surface of BP nanosheets and enhance the interfacial interactions between BP nanosheets and thermoplastic polyurethane (TPU) matrix. Compared to pure BP nanosheets, MA@BP nanosheets present more efficient suppression effects in heat release and toxic CO production. Besides, due to the photo-thermal conversion effect of BP nanosheets, TPU-MA@BP-2.0 presents an equilibrium temperature of ∼80 oC under simulated sunlight of 1.0 kW/m2 and a significant solar de-icing performance. The solve-free and hydrogen-bond assembly method not only solves the lack problem of functional groups for the functionalization of BP nanosheets, but also develops a flame-retardant and photo-thermal polymer nanocomposite applied in various occasions.
在此,我们从生物蛋白质的分层结构中得到启发,通过调节水溶液的温度来控制三聚氰胺(MA)分子间氢键的展开和重组,从而制备出三聚氰胺功能化黑磷(MA@BP)纳米片。第一性原理计算证实,三聚氰胺可自发吸附在黑磷纳米片表面,并增强黑磷纳米片与热塑性聚氨酯(TPU)基体之间的界面相互作用。与纯 BP 纳米片相比,MA@BP 纳米片能更有效地抑制热释放和有毒 CO 的产生。此外,由于 BP 纳米片的光热转换效应,TPU-MA@BP-2.0,在 1.0 kW/m2 模拟太阳光下的平衡温度可达 ∼ 80 oC,具有显著的太阳能除冰性能。无溶剂和氢键组装法不仅解决了 BP 纳米片功能化所需的官能团缺乏的问题,还开发出一种阻燃和光热聚合物纳米复合材料,可应用于多种场合。
Polyelectrolyte composite hydrogels based on a derivative of functional dietary fiber for long-term gastric retention and drug delivery
Jueying Yang, Ying Wang, Ailing Wei, Kelin Peng, Rui Huang, Zhenfei Wang, Xilan Ma, Qingquan Tian, Yu Chen
doi:10.1016/j.compositesb.2024.111194
基于功能性膳食纤维衍生物的聚电解质复合水凝胶,用于长期胃保留和给药
Gastric retention drug delivery is experiencing significant demand for hydrogels that exhibit in situ controllable forming in the stomach, resistance against severe gastric degradation, and exceptional biocompatibility. However, current studies lack comprehensive investigations on these requirements. In this study, resistant starch is chosen as a kind of novel dietary fiber with remarkable gastric retention effects compared to conventional natural polymers. To address its limited solubility, resistant starch was modified by carboxymethyl groups. Moreover, a semi-dissolution acidification sol–gel transition method was employed to enable in situ gelation under gastric acid conditions and fabricate physically crosslinked polyelectrolyte composite hydrogels (CMRS/CTS) based on carboxymethylated resistant starch and chitosan. This method obviates the need for toxic chemical crosslinkers and initiators, ensuring favorable biocompatibility. The influence of carboxymethyl substitution degree and the anion-to-cation ratio of the composite hydrogels on the mechanical, rheological, and swelling properties was thoroughly investigated. Compared to conventional carboxymethyl starch-based hydrogels, CMRS/CTS maintained a relatively intact structure even after immersion in simulated gastric fluid for 30 days owing to the enzymatic stability of the hydrogel. Upon drug loading, CMRS/CTS exhibited sustained and controlled drug release, facilitating prolonged therapeutic effects. Simultaneously achieving in situ gastric drug release, biocompatibility, resistance to degradation, and sustained release, CMRS/CTS represents a promising avenue for the development of long-term gastric retention hydrogels.
胃保留给药对水凝胶的需求量很大,这些水凝胶在胃中的原位成型可控,能抵抗严重的胃降解,并具有优异的生物相容性。然而,目前的研究缺乏对这些要求的全面调查。本研究选择了抗性淀粉作为一种新型膳食纤维,与传统的天然聚合物相比,抗性淀粉具有显著的胃保留效果。为了解决抗性淀粉溶解度有限的问题,研究人员对其进行了羧甲基改性。此外,该研究还采用了一种半溶解酸化溶胶-凝胶转变方法,在胃酸条件下实现原位凝胶化,并制备出基于羧甲基化抗性淀粉和壳聚糖的物理交联聚电解质复合水凝胶(CMRS/CTS)。这种方法无需使用有毒的化学交联剂和引发剂,确保了良好的生物相容性。研究人员深入研究了复合水凝胶的羧甲基取代度和阴阳离子比对其机械、流变和溶胀性能的影响。与传统的羧甲基淀粉基水凝胶相比,由于水凝胶的酶稳定性,CMRS/CTS 在模拟胃液中浸泡 30 天后仍能保持相对完整的结构。加载药物后,CMRS/CTS 表现出持续、可控的药物释放,从而延长了治疗效果。CMRS/CTS 可同时实现原位胃药释放、生物相容性、抗降解性和持续释放,是开发长期胃保留水凝胶的一个很有前景的途径。
Porous PLGA/MBG scaffold enhanced bone regeneration through osteoimmunomodulation
Yang Liu, Shuang Zhang, Xiaohui Zhang, Luli Ji, Hongmeng Yu, Jing Wang, Changsheng Liu
doi:10.1016/j.compositesb.2024.111202
多孔 PLGA/MBG 支架通过骨免疫调节促进骨再生
The role of osteoimmunomodulation in orthopedic biomaterials has been demonstrated to be crucial in the regulation of bone repair and regeneration. Macrophages, the primary effector cells in the immune response to biomaterials, are highly heterogeneous and plastic, making them a prime target for immunomodulation. Mesoporous bioactive glass (MBG) is widely recognized for its biocompatibility, osteoconductivity, osteoinductivity, and immunomodulatory properties. However, the impact of MBG content on macrophage response remains unclear. To fill this knowledge gap, we designed a series of hierarchical PLGA-based composite scaffolds with varying MBG contents (0 %, 10 %, 20 % and 40 %, named as P, P10M, P20M and P40M, respectively) to investigate the osteoimmunomodulatory effects of these scaffolds. Our findings indicated that the P10M scaffolds showed a faster immune response in the early stage and exhibited superior ability to shift the pro-inflammatory immune microenvironment towards an anti-inflammatory state in the later stage, thereby enhancing the angiogenic potential of HUVECs and the osteogenic capacity of BMSCs. Furthermore, the in vivo implantation demonstrated that the immune microenvironment induced by P10M scaffolds facilitated optimal neovascularization and ectopic bone formation. These findings establish a theoretical foundation for the development of bone immunoregulatory biomaterials doped with MBG, which can effectively promote bone repair and regeneration.
骨科生物材料中的骨免疫调节作用已被证明在调节骨修复和再生方面至关重要。巨噬细胞是生物材料免疫反应的主要效应细胞,具有高度异质性和可塑性,因此是免疫调节的主要目标。介孔生物活性玻璃(MBG)的生物相容性、骨传导性、骨传导性和免疫调节特性已得到广泛认可。然而,MBG 含量对巨噬细胞反应的影响仍不清楚。为了填补这一知识空白,我们设计了一系列不同 MBG 含量(0%、10%、20% 和 40%,分别命名为 P、P10M、P20M 和 P40M)的基于 PLGA 的分层复合支架,以研究这些支架的骨免疫调节作用。我们的研究结果表明,P10M 支架在早期阶段表现出更快的免疫反应,在后期阶段则表现出卓越的能力,能将促炎免疫微环境转变为抗炎状态,从而增强 HUVECs 的血管生成潜能和 BMSCs 的成骨能力。此外,体内植入实验表明,P10M 支架诱导的免疫微环境促进了最佳的新生血管生成和异位骨形成。这些发现为开发掺杂 MBG 的骨免疫调节生物材料奠定了理论基础,它能有效促进骨修复和再生。
Digital twin and cross-scale mechanical interaction for fabric rubber composites considering model uncertainties
Xiaoyao Xu, Guowen Wang, Shanyong Xuan, Yimeng Shan, Heng Yang, Xuefeng Yao
doi:10.1016/j.compscitech.2024.110431
考虑模型不确定性的织物橡胶复合材料数字孪生和跨尺度机械相互作用
Digital twin ushers in growth as one cutting-edge technology that enables high-precision, informative and real-time interaction of advanced composites, influencing the paradigm of composite analysis and design in aerospace, automotive, intelligent electronics and other fields. The online and fine evolution of digital twins at scale face challenges due to creating scalable predictions, updates, and controls with coupled information in workflows. In this work, an interactive digital twin methodology for complex composite structures (CCSDT) based on machine learning is introduced. To demonstrate the framework's feasibility and applicability, a hybrid architecture comprising hierarchical deep neural networks (H-DNNs), statistical inference and cross-scale physical constraints is proposed considering the fabric rubber composites (FRC) in aerospace field. The framework predicts 3D displacement and stress fields directly from sensing features and can incorporate dynamic updating and evaluation of computational models into data assimilation. Real-time prediction and uncertainty quantification are verified through synthetic and experimental data, and the capability of CCSDT in perception and decision is demonstrated by a case of cruise state monitoring. The comparison between the measured strain and the post-processing predicted strain field shows the extensibility of the direct prediction results. These results provide guidance for the development of composite digital twins, stimulating the potential for cost-effective and efficient digital twin services.
数字孪生作为一项前沿技术迎来了发展机遇,它实现了先进复合材料的高精度、信息化和实时交互,影响了航空航天、汽车、智能电子等领域的复合材料分析和设计模式。大规模数字孪生的在线和精细演化面临着挑战,因为要在工作流中利用耦合信息创建可扩展的预测、更新和控制。在这项工作中,介绍了一种基于机器学习的复杂复合结构交互式数字孪生方法(CCSDT)。为了证明该框架的可行性和适用性,考虑到航空航天领域的织物橡胶复合材料(FRC),提出了一种由分层深度神经网络(H-DNN)、统计推理和跨尺度物理约束组成的混合架构。该框架可直接从传感特征预测三维位移和应力场,并可将计算模型的动态更新和评估纳入数据同化。通过合成和实验数据验证了实时预测和不确定性量化,并通过巡航状态监测案例证明了 CCSDT 在感知和决策方面的能力。测量应变与后处理预测应变场之间的比较显示了直接预测结果的可扩展性。这些结果为开发复合数字孪生提供了指导,激发了提供经济高效的数字孪生服务的潜力。
A deep transfer learning approach to construct the allowable load space of notched composite laminates
Yushu Li, Huasong Qin, V.B.C. Tan, Liyong Jia, Yilun Liu
doi:10.1016/j.compscitech.2024.110432
构建缺口复合材料层压板容许载荷空间的深度迁移学习方法
Allowable load is one of the core parameters for the design and service of composite structures (CSs). However, due to the large design parameters, cumbersome design procedure and complicated simulation model of CSs, considerable amounts of experiments and simulations are needed to determine the allowable load of CSs, which is costly and inefficient, hindering the wide application of CSs in industry. In this work, we present a general deep transfer learning approach to construct the allowable load space (ALS) of notched laminates by considering various design parameters such as geometries, materials, stacking angles, ply numbers, laminate types and load types. Initially, an ensemble deep neural network (Ensemble) is trained, which can predict the allowable loads of notched laminate with known design parameters well. Here the Ensemble guided by ensemble learning is trained to reduce the errors generated by manually setting. Then, the pre-trained Ensemble is transferred to new design parameters by fine-tuning it with scarce new samples. Finally, the ALS of notch laminates is constructed by integrating the pre-trained and fine-tuned models, covering both known and diverse new design parameters. Our approach can easily be extended to other CSs.
容许载荷是复合材料结构(CS)设计和使用的核心参数之一。然而,由于 CS 的设计参数大、设计程序繁琐、仿真模型复杂,确定 CS 的容许载荷需要大量的实验和仿真,成本高、效率低,阻碍了 CS 在工业领域的广泛应用。在这项工作中,我们提出了一种通用的深度迁移学习方法,通过考虑各种设计参数(如几何形状、材料、堆叠角度、层数、层压板类型和负载类型)来构建缺口层压板的允许负载空间(ALS)。首先,训练一个集 合深度神经网络(Ensemble),它能很好地预测已知设计参数下缺口层压板的容许载荷。在此,以集 合学习为指导训练集 合,以减少手动设置产生的误差。然后,利用稀缺的新样本进行微调,将预先训练好的集 合转移到新的设计参数上。最后,通过整合预训练和微调模型,构建缺口层压板的 ALS,涵盖已知和各种新设计参数。我们的方法很容易扩展到其他 CS。
Characterization of migration behavior of organic electric-field regulator in polyethylene composite based on the synchronous spectra of space charge and polarization current
Yongjun Li, Yongsen Han, Yunlong Sun, Zhonghua Li
doi:10.1016/j.compscitech.2024.110437
基于空间电荷和极化电流同步光谱的聚乙烯复合材料中有机电场调节器迁移行为的表征
Organic electric-field regulator has the ability to suppress the space charge accumulation in the composite due to its electric-field and filler-content enhanced conductivity. Moreover, it can also migrate towards the high electric field region under the electric field gradient force, which further homogenizes the non-uniform electric field distribution. To characterize the migration behavior of the organic electric-field regulator in the composite under electric field, a distributed equivalent circuit model is firstly introduced, and it is solved to obtain the space-time distribution of conductivity in composite based on the synchronous spectra of space charge and polarization current. Combining the mathematical relationship between the direct current (DC) conductivity and electric field as well as regulator content, the space-time distribution of organic electric-field regulator in the composite is then settled. The allyloxy polyethylene glycol (APEG) is used as an example organic electric-field regulator and is filled into low-density polyethylene (LDPE) matrix to prepare composites. The DC conductivity and the synchronous spectra of space charge and polarization current are measured, respectively. The composites show noticeable electric-field and regulator-content enhanced conductivities. The space charge distribution shows that the APEG is capable of suppressing the space charge and homogenizing the electric field distribution compared with pure LDPE. The space-time distribution of regulator content in the 0.5 wt% composite is determined by the proposed method, and the regulator content near the electrodes is much higher than in the bulk, which is consistent with the infrared microscope images. The higher filler content means a higher DC conductivity, which lowers the high electric field near the electrodes and contributes to more uniform electric field distribution in the composite. The proposed method experimentally characterizes the migration behavior of the organic electric-field regulator in the polymer composite for the first time, and provides an effective way to study the migration mechanism of organic molecules (e.g. organic electric-field regulator) in the polymer composite.
有机电场调节剂由于其电场和填料含量增强的导电性,能够抑制复合材料中的空间电荷积累。此外,在电场梯度力的作用下,它还能向高电场区域迁移,从而进一步均匀非均匀电场分布。为了表征电场作用下复合材料中有机电场调节剂的迁移行为,首先引入了分布式等效电路模型,并根据空间电荷和极化电流的同步谱求解得到了复合材料中电导率的时空分布。结合直流(DC)电导率与电场以及调节剂含量之间的数学关系,解决了有机电场调节剂在复合材料中的时空分布问题。以烯丙氧基聚乙二醇(APEG)为例,将其填充到低密度聚乙烯(LDPE)基体中制备复合材料。分别测量了直流电导以及空间电荷和极化电流的同步频谱。复合材料显示出明显的电场和调节剂含量增强导电性。空间电荷分布表明,与纯低密度聚乙烯相比,APEG 能够抑制空间电荷并均匀电场分布。通过所提出的方法确定了 0.5 wt% 复合材料中调节剂含量的时空分布,电极附近的调节剂含量远高于主体,这与红外显微镜图像一致。较高的填料含量意味着较高的直流电导率,从而降低了电极附近的高电场,使复合材料中的电场分布更加均匀。所提出的方法首次通过实验表征了有机电场调节剂在聚合物复合材料中的迁移行为,为研究有机分子(如有机电场调节剂)在聚合物复合材料中的迁移机理提供了有效途径。