今日更新:Composite Structures 5 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 2 篇
Influence of geometry on in-plane and out-of-plane wave propagation of 2D hexagonal and re-entrant lattices
Somraj Sen, Arindam Das, Indrajit Pahari, Arnab Banerjee
doi:10.1016/j.compstruct.2025.118958
几何形状对二维六边形和可重入格面内和面外波传播的影响
The evaluation of the dispersion characteristics, including iso-frequency contours, group velocity maps, and directivity plots, are presented for 2D periodic lattices with varying internal angles. This study delves into the wave propagation behavior of various lattices to understand the emergence of wave directionality through variations in geometry, particularly internal angles, considering both in-plane and out-of-plane deformations. The spectral element formulation is used to model each lattice member considering space frame elements. The Bloch-Floquet theorem is employed to establish the dispersion relationships after defining the periodicity of unit cells. Detailed analysis manifests that isofrequency contours become more concave as internal angles decrease, indicating high directionality in re-entrant lattices. This is confirmed by directivity plots and group velocity maps. Modes, namely axial, flexural, and torsional modes are identified for the regular hexagonal lattice. Further, Dirac cones are observed for the hexagonal lattice. Notably, a directional roton-like phenomenon is discovered, displaying both negative and positive group velocities for specific wave packets. These findings have potential applications for wave manipulation and control, particularly in acoustics and vibration control.
本文给出了具有不同内角的二维周期晶格的色散特性的评价,包括等频等高线、群速度图和指向性图。本研究深入研究了各种晶格的波传播行为,以了解通过几何变化,特别是内角,考虑到面内和面外变形,波的方向性的出现。考虑空间框架元素,采用谱元公式对每个格元进行建模。在定义了单元格的周期性后,利用Bloch-Floquet定理建立了色散关系。详细分析表明,随着内角的减小,等频轮廓变得更加凹,表明在重入格中具有较高的方向性。指向性图和群速度图证实了这一点。正六边形晶格的模态,即轴向、弯曲和扭转模态。此外,在六边形晶格中观察到狄拉克锥。值得注意的是,发现了一种方向性的类似旋转的现象,显示了特定波包的负和正群速度。这些发现在波浪操纵和控制方面具有潜在的应用,特别是在声学和振动控制方面。
Modeling of variable angle tow composites using a variable separation method based on a unified formulation
P. Vidal, G. Giunta, D.A. Iannotta, L. Gallimard, O. Polit
doi:10.1016/j.compstruct.2025.118963
基于统一公式的可变分离变角度复合材料建模
In this article, we are interested in the modeling of variable stiffness plate structures through a variable separation approach. The displacement field is approximated as a sum of separated functions of the in-plane coordinates x, y and the transverse coordinate z. A non-linear problem is derived. It can be solved using an iterative process involving 2D and 1D linear problems successively. To keep the separability feature ensuring a computational efficiency, the so-called Carrera’s Unified Formulation (CUF) is adapted to our framework. Classical Finite Element method is used. In the thickness direction, a fourth-order expansion in each layer is considered. The number of unknowns is reduced compared to classical LayerWise (LW) approach. Test cases encountered in the literature are provided to assess the present LW method and compare the results with reference solutions. Laminated and sandwich structures with different slenderness ratios and variations of angle tows are addressed. Very satisfacfory results with a low computational cost are obtained.
在本文中,我们通过变量分离法对变刚度板结构进行建模。位移场被近似为平面内坐标 x、y 和横向坐标 z 的分离函数之和。由此推导出一个非线性问题,该问题可通过依次求解二维和一维线性问题的迭代过程来解决。为了保持可分离性特征以确保计算效率,我们对所谓的卡雷拉统一公式(CUF)进行了调整以适应我们的框架。采用经典的有限元法。在厚度方向上,每层考虑四阶展开。与经典的层合(LW)方法相比,未知数的数量减少了。提供了文献中遇到的测试案例,以评估当前的 LW 方法,并将结果与参考解进行比较。研究了具有不同长细比和角度层变化的层合和夹层结构。获得了计算成本低且非常令人满意的成果。
Inverse design of lattice metamaterials for fully anisotropic elastic constants: A data-driven and gradient-based method
Zixing Fu, Huina Mao, Binglun Yin
doi:10.1016/j.compstruct.2025.118975
完全各向异性弹性常数的晶格超材料的反设计:数据驱动和基于梯度的方法
The elastic constant tensor and its anisotropy are among the most critical mechanical properties, as they govern numerous mechanical phenomena and are prevalent in many natural materials. However, the efficient and accurate inverse design of metamaterials with desired elastic constants remains challenging, particularly for fully anisotropic elastic constants with low symmetries. Recent advances in artificial intelligence have opened new avenues to address this challenge. In this work, we propose a general framework that combines data-driven artificial neural networks with a gradient-based optimization algorithm to achieve high-precision inverse design of fully anisotropic elastic constants, exemplified using open cellular lattice Kelvin cells. First, an automatic parametric finite element method is introduced to calculate the elastic constants of any (distorted) Kelvin cells. Next, neural networks are developed to approximate the computationally costly finite element method, acting as the forward characterization function in the design process. Finally, an inverse design framework that integrates neural networks with a gradient-based optimization algorithm is proposed and validated. The successful design outcomes in practical examples, such as artificial bone implants and structures with unconventional Poisson’s ratios, demonstrate the capability of our method to guide high-precision inverse design across various engineering applications.
弹性常数张量及其各向异性是最关键的力学性能之一,因为它们控制着许多力学现象,并普遍存在于许多天然材料中。然而,具有理想弹性常数的超材料的有效和精确的反设计仍然具有挑战性,特别是对于具有低对称性的完全各向异性弹性常数。人工智能的最新进展为解决这一挑战开辟了新的途径。在这项工作中,我们提出了一个通用框架,将数据驱动的人工神经网络与基于梯度的优化算法相结合,以实现完全各向异性弹性常数的高精度反设计,例如使用开放细胞晶格开尔文细胞。首先,引入一种自动参数有限元方法来计算任意(畸变)开尔文单元的弹性常数。其次,开发神经网络来近似计算成本高昂的有限元方法,作为设计过程中的前向表征函数。最后,提出并验证了将神经网络与梯度优化算法相结合的逆向设计框架。在实际例子中,如人工骨植入物和非常规泊松比结构的成功设计结果,证明了我们的方法在各种工程应用中指导高精度逆设计的能力。
Experimental compressive damage analysis on holed laminates under dynamic loadings using in-situ MHz synchrotron X-ray phase contrast imaging
J.M. Rodríguez-Sereno, J. Pernas-Sánchez, J.A. Artero-Guerrero, A. Rack, A. Vaz-Romero, J. López-Puente, D. Varas, F. Naya, A. Cohen, B. Lukić
doi:10.1016/j.compstruct.2025.118978
利用原位MHz同步x射线相衬成像技术分析动载荷作用下多孔层压板的压缩损伤
This study highlights the importance of investigating the behavior of the inner layers of carbon fiber-reinforced polymer (CFRP) laminates under dynamic compression, using Synchrotron-based techniques to understand damage initiation and failure propagation at high strain rates. Open and filled hole specimens with three different CFRP architectures were tested using the Split Hopkinson Pressure Bar (SHPB). Digital image correlation (DIC) and Synchrotron-based X-ray MHz radiography were performed simultaneously with ultra high-speed cameras (two Shimadzu HPV-X2 for X-ray images and one Photron SAZ for visible light). This allowed the first observation of matching outer and inner failures with surface strain fields at a micrometer level. Results showed that, in certain conditions, failure initiated earlier in the inner layers, leading to through-thickness propagation. This correlation between strength and internal damage initiation might be overlooked if only outer visible light images are used. The proposed methodology, which emphasized post-processing of X-ray images, can serve as a baseline for future research on the behavior of inner layers of composite materials under high strain rates. Additionally, analysis of different CFRP architectures revealed their influence on unloading time after initial failure.
这项研究强调了研究碳纤维增强聚合物(CFRP)层压板内层在动态压缩下的行为的重要性,使用基于同步加速器的技术来了解高应变率下的损伤起裂和失效扩展。采用分离式霍普金森压杆(SHPB)对三种不同CFRP结构的开孔和填孔试件进行了测试。采用超高速相机(两台Shimadzu HPV-X2拍摄x射线图像,一台Photron SAZ拍摄可见光图像)同时进行数字图像相关(DIC)和基于同步加速器的x射线MHz摄影。这使得首次观察到在微米水平上匹配表面应变场的外部和内部失效。结果表明,在一定条件下,内层的破坏开始得更早,导致了穿层扩展。如果只使用外部可见光图像,强度和内部损伤之间的相关性可能会被忽略。所提出的方法强调了x射线图像的后处理,可以作为未来研究复合材料内层在高应变率下行为的基线。此外,分析了不同CFRP结构对初始破坏后卸载时间的影响。
Impact damage detection on carbon fiber reinforced polymer tube by a mutual differential Bobbin probe
Wei Guo, Lihua Guo, Hao Xu, Weijun Zhu, Shejuan Xie, Zhenmao Chen, Toshiyuki Takagi, Tetsuya Uchimoto
doi:10.1016/j.compositesa.2025.108806
用互差筒管探头检测碳纤维增强聚合物管的冲击损伤
Carbon fiber reinforced polymer (CFRP) tube is utilized in large aperture deployable space antennas for its superior material properties. Impact damages on CFRP tube can significantly impair the load-bearing capacity of the tubes. Efficient and convenient non-destructive evaluation method of impact damage in CFRP tubes is essential. This study develops a high-frequency eddy current testing (HF ECT) finite element analysis method that accounts for both the dielectric properties and anisotropic conductivity of CFRP, and establishes a fiber bundle model that explains the operating mechanism of displacement current and eddy currents in CFRP, offering guidance for predicting HF ECT signals in CFRP. A high signal-to-noise ratio mutual differential Bobbin probe is developed specifically for detecting impact damage in CFRP tubes. A HF ECT experiment system is constructed and validated using impact damages induced by a force hammer, demonstrating the effectiveness of method and probe, and the invisible impact defect is detected successfully.
碳纤维增强聚合物(CFRP)管以其优越的材料性能被应用于大孔径可展开空间天线中。CFRP钢管的冲击损伤会严重影响钢管的承载能力。高效、便捷的CFRP管材冲击损伤无损评价方法是至关重要的。本研究发展了同时考虑CFRP介电性能和各向异性电导率的高频涡流测试(HF ECT)有限元分析方法,并建立了解释CFRP中位移电流和涡流作用机理的纤维束模型,为预测CFRP中高频ECT信号提供指导。研制了一种高信噪比互差筒管探头,专门用于检测CFRP管的冲击损伤。利用力锤冲击损伤构建了高频电刺 激实验系统并进行了验证,验证了方法和探头的有效性,成功检测出了不可见的冲击缺陷。
Co-training of multiple neural networks for simultaneous optimization and training of physics-informed neural networks for composite curing
Keith D. Humfeld, Geun Young Kim, Ji Ho Jeon, John Hoffman, Allison Brown, Jonathan Colton, Shreyes Melkote, Vinh Nguyen
doi:10.1016/j.compositesa.2025.108820
复合材料固化过程中多个神经网络同时优化的协同训练和物理信息神经网络的训练
This paper introduces a Physics-Informed Neural Network (PINN) technique that co-trains neural networks (NNs) that represent each function in a system of equations to simultaneously solve equations representing an out-of-autoclave (OOA) cure process while conducting optimization in adherence to process requirements. Specifically, this co-training approach benefits from using NNs to represent OOA inputs (air temperature profile) and outputs (part and tool temperature profiles and degree of cure). Production requirements can then be levied on the inputs, such as maximum air temperature and minimum cure cycle, and simultaneously on the outputs, such as degree of cure, maximum part temperature, and part temperature rate limits. Co-training the NNs results in an optimized input producing outputs that meet all OOA process requirements. The technique is validated with finite element (FE) simulations and physical experiments for curing a Toray T830H-6 K/3900-2D composite panel. Hence, this novel approach efficiently models and optimizes the OOA cure process.
本文介绍了一种物理信息神经网络(PINN)技术,该技术共同训练代表方程系统中每个函数的神经网络(nn),以同时求解代表高压灭菌器外(OOA)固化过程的方程,同时根据工艺要求进行优化。具体来说,这种协同训练方法得益于使用神经网络来表示OOA输入(空气温度曲线)和输出(零件和工具温度曲线以及固化程度)。然后,可以对输入进行生产要求,例如最高空气温度和最低固化周期,同时对输出进行生产要求,例如固化程度、最高部件温度和部件温度速率限制。共同训练神经网络的结果是一个优化的输入,产生满足所有OOA过程要求的输出。通过对东丽T830H-6 K/3900-2D复合材料板的有限元模拟和物理实验验证了该技术的有效性。因此,这种新方法有效地建模和优化了OOA固化过程。
Shear behavior and strain transmission mechanism in bonding interface of robust toughened epoxy/flattened bamboo composites
Qingdi Jia, Mingjie Guan, Shuai Qian, Mengyu Wu, Pulin Che, Xu Liu
doi:10.1016/j.compositesb.2025.112334
坚固增韧环氧树脂/扁平竹复合材料界面剪切行为及应变传递机理
To improve the brittle bonding interface of epoxy/flattened bamboo composite (EFB) and expand its application in bamboo buildings, the effects of bonding structures, alkali-treated surface, and toughened epoxy on shear bonding behavior of EFB were systemically investigated to completely understand bonding interface mechanism and novelly simulated models was analyzed. The microstructure and chemical bonding group of the EFB bonding interface were characterized to reveal the toughening bonding mechanisms. The tensile shear behavior of the bonding interface was analyzed by digital image correlation (DIC) and the strain transfer mechanism was simulated by finite element analysis (FEA). Results indicated that the bonding interphase between epoxy and flattened bamboo primarily involved mechanical interlocking in the bonding interface and chemical bonding in the parenchyma cells. The alkali-treated surface and toughened epoxy group (ATEG) improved epoxy penetration on flattened bamboo surface changing the interphase between epoxy and bamboo interface. Alkali-treated surface and toughened epoxy significantly enhanced shear strength and fracture energy of EFB. The maximum dry shear strength of ATEG was higher than control group, with increases varying across the three bonding structures. Under hygrothermal conditions, ATEG achieved the highest wet shear strength in core-reinforced structure with bamboo failure of 60%. DIC analysis revealed the improvement of strain continuity and dispersion in ATEG under dry conditions, while strain concentration occurred mainly in interphase of EFB bonding interface under hygrothermal conditions leading to the debonding failure. FEA illustrated that alkali-treated surface and toughened epoxy reduced strain concentration in the interphase of bonding interface and improved strain distribution of EFB, consistent with DIC analysis.
为改善环氧/扁平竹复合材料的脆性粘结界面,扩大其在竹建筑中的应用,系统研究了粘结结构、碱处理表面和增韧环氧树脂对环氧/扁平竹复合材料剪切粘结行为的影响,以全面了解环氧/扁平竹复合材料的粘结界面机理,并建立了新的模拟模型。通过对EFB结合界面的微观结构和化学结合基团的表征,揭示了其增韧结合机理。采用数字图像相关(DIC)分析了粘结界面的拉伸剪切行为,并采用有限元分析(FEA)模拟了应变传递机理。结果表明,环氧树脂与扁平竹的键合界面主要为键合界面的机械互锁和薄壁细胞的化学键合。碱处理表面和增韧环氧基(ATEG)改善了环氧树脂在扁平竹表面的渗透,改变了环氧树脂与竹界面的界面相。碱处理表面和增韧环氧树脂显著提高了EFB的抗剪强度和断裂能。ATEG的最大干抗剪强度高于对照组,三种粘结结构的最大干抗剪强度均有所增加。在湿热条件下,ATEG在竹破坏率为60%的核心钢筋结构中湿抗剪强度最高。DIC分析显示,干燥条件下ATEG的应变连续性和分散性得到改善,而湿热条件下应变集中主要发生在EFB粘结界面界面,导致脱粘失效。有限元分析结果表明,碱处理表面和增韧环氧树脂降低了键合界面界面的应变浓度,改善了EFB的应变分布,与DIC分析结果一致。
Comparative Analysis of NOL-Ring Tensile Strength in Towpreg and Slit-Tape for Filament Winding: Influence of Resin Viscosity, Tack, and Consolidation
Eduardo Szpoganicz, Fabian Hübner, Marius Luik, Jeremias Thomas, Florian Max, Andreas Scherer, Tobias Dickhut, Holger Ruckdäschel
doi:10.1016/j.compscitech.2025.111123
长丝卷绕用丝带和开缝带no - ring抗拉强度的对比分析:树脂粘度、粘性和固结的影响
This study investigates the tensile strength of carbon-fiber reinforced polymer (CFRP) specimens manufactured via filament winding with varying winding parameters. NOL-rings (Naval Ordnance Laboratories) were processed using unidirectional CFRP material, and the performance of towpregs was compared to slit-tapes of different widths and temperature settings. To establish a benchmark, autoclave-cured prepregs were laminated into flat rectangular samples. The manufacturing process revealed significant variations in laminate strength and ply consolidation, analyzed through optical micrographs and profile analysis. Tensile strengths of the NOL-rings ranged from 1430 MPa to 1800 MPa, with towpregs performing better due to higher tackiness and improved consolidation, compared to slit-tapes with no applied temperature. However, both were still bellow the 2100 MPa strength of autoclave-cured reference samples. Finite element analysis showed that the NOL-ring geometry induces bending stresses, even in an idealized part, reducing the theoretical tensile strength to 1900 MPa. Additionally, in-situ cryogenic testing using liquid nitrogen was reported for the first time for NOL-ring specimens, revealed a significant increase in strength to 2200 MPa, attributed to the stiffening effect at low temperatures. This work introduces a novel approach by correlating ply consolidation with slit-tapes, towpregs, and winding parameters, linking prepreg tackiness to tensile performance, and presenting additionally testing of NOL-rings at 77 K, thus providing understanding of their behavior in cryogenic environments.
研究了不同缠绕参数下碳纤维增强聚合物(CFRP)长丝缠绕试样的拉伸强度。采用单向CFRP材料加工no -rings (Naval ororance Laboratories),并将其与不同宽度和温度设置的缝带的性能进行了比较。为了建立一个基准,蒸压固化的预浸料被层压成扁平的矩形样品。通过光学显微照片和剖面分析,制造过程揭示了层压强度和层压固结的显著变化。nol环的抗拉强度从1430 MPa到1800 MPa不等,与没有施加温度的缝带相比,拖带具有更高的粘性和更好的固结性,因此性能更好。然而,两者的强度仍低于蒸压罐固化参考样品的2100 MPa。有限元分析表明,即使在理想的零件上,NOL-ring几何形状也会产生弯曲应力,使理论抗拉强度降低到1900 MPa。此外,首次报道了使用液氮对no -ring试件进行的原位低温测试,结果显示,由于低温下的硬化效应,no -ring试件的强度显著提高至2200 MPa。这项工作介绍了一种新的方法,通过将胶层固结与缝带,带浸料和缠绕参数相关联,将预浸料粘性与拉伸性能联系起来,并在77 K下进行了noll环的额外测试,从而了解了它们在低温环境中的行为。
Macro/Micro Synergistic Thermal Conductivity Enhancement in Liquid Metal-Based Phase Change Composites for Thermal Management in Electronic Devices
Guangyin Liu, Kaixun Shang, Shiqi Chen, Jun Shen
doi:10.1016/j.compscitech.2025.111120
用于电子器件热管理的液态金属基相变复合材料的宏/微协同导热增强
Liquid metals (LM) demonstrate significant potential in thermal management applications for electronic devices due to their high thermal conductivity and phase change heat absorption capabilities. However, when combined with organic flexible substrates to create composite materials, the advantages of high thermal conductivity can be substantially diminished. To address this challenge, this study proposes a macro/micro synergistic thermal conductivity enhancement method. By coating LM particles with carbon nanotubes (CNT), the LM@CNT particles that mimics a "neuron" structure was developed. LM@CNT was combined with silicone rubber (SR) to form the LM@CNT/SR, which exhibits micro-level thermal conductivity enhancement. The integration of LM@CNT in SR establishes a thermal conduction network, resulting in a thermal conductivity of 1.37 W/m/K for the LM@CNT/SR. Inspired by the growth rings in tree trunks, vertically aligned graphene films (VAGF) are ingeniously embedded in the composite material to enhance thermal conductivity at the macro-level. The results show that embedding 0.02 mm thick VAGF can increase thermal conductivity by 8.8 W/m/K, while 0.1 mm thick VAGF can achieve an increase of 24.7 W/m/K. The thermal conductivity of LM@CNT/SR/VAGF has obvious anisotropy. Furthermore, the LM@CNT/SR/VAGF demonstrates excellent stability, with negligible changes in thermal conductivity after nearly 2000 temperature cycles. The methodology proposed in this study for producing high thermal conductivity phase change composite materials employs simple and cost-effective processes, offering a novel framework for the mass production of such composites. This approach shows substantial potential for applications in thermal surge protection and thermal management within electronic devices.
液态金属(LM)由于其高导热性和相变吸热能力,在电子器件的热管理应用中显示出巨大的潜力。然而,当与有机柔性基板结合以创建复合材料时,高导热性的优点可以大大减少。为了解决这一挑战,本研究提出了一种宏观/微观协同增强导热系数的方法。通过用碳纳米管(CNT)涂覆LM颗粒,开发了模拟“神经元”结构的LM@CNT颗粒。LM@CNT与硅橡胶(SR)结合形成LM@CNT/SR,具有微级导热性能增强。LM@CNT在SR中的集成建立了一个导热网络,使得LM@CNT/SR的导热系数为1.37 W/m/K。受树干年轮的启发,垂直排列的石墨烯薄膜(VAGF)巧妙地嵌入复合材料中,以增强宏观上的导热性。结果表明,嵌入0.02 mm厚的VAGF可使导热系数提高8.8 W/m/K,而0.1 mm厚的VAGF可使导热系数提高24.7 W/m/K。LM@CNT/SR/VAGF的导热系数具有明显的各向异性。此外,LM@CNT/SR/VAGF表现出优异的稳定性,在近2000次温度循环后,导热系数的变化可以忽略不计。本研究中提出的生产高导热相变复合材料的方法采用简单且具有成本效益的工艺,为大规模生产此类复合材料提供了新的框架。这种方法在电子设备的热涌保护和热管理方面显示出巨大的应用潜力。