【新文速递】2024年7月6日复合材料SCI期刊最新文章

   

今日更新：Composite Structures 7 篇，Composites Part A: Applied Science and Manufacturing 4 篇，Composites Part B: Engineering 6 篇，Composites Science and Technology 1 篇

Composite Structures

Buckling behaviors prediction of biological staggered composites with finite element analysis and machine learning coupled method

Siyuan Zhang, Biao Zhao, Shun Zhu, Yanwei Liu

doi:10.1016/j.compstruct.2024.118357

用有限元分析和机器学习耦合方法预测生物交错复合材料的屈曲行为

Staggered structure, where mineral crystals are arranged in a staggered manner in protein matrix, is the most representative microstructure in biological composites. Because of the elongated geometry and large aspect ratio of mineral crystals, their failure mechanism under compressive loading is predominantly controlled by buckling. The microstructural complexity, diversity of the constituent materials, and the complexity of buckling behaviors present substantial challenges for the precise forecasting of the buckling behavior of biological materials. In this paper, a novel method combining finite element analysis with machine learning is proposed. Specifically, based on the large dataset obtained using the finite element method, the buckling strength of biological staggered composites was rapidly predicted using a machine learning algorithm. Herein, the effects of microstructure and component materials on buckling behavior have been investigated systematically. The results indicate that the neural network models are highly accurate in predicting critical buckling strength. Aspect ratio and modulus ratio significantly affect the critical buckling strength of staggered structures according to the results of feature importance analysis. Additionally, the post-buckling modes of staggered structures exhibit heightened sensitivity to initial geometric defects, particularly in higher-order buckling modes. Our research provides valuable insights into fast and accurate prediction of the buckling behavior of biological composites and their design.

交错结构是指矿物晶体在蛋白质基质中交错排列，是生物复合材料中最具代表性的微观结构。由于矿物晶体具有细长的几何形状和较大的长宽比，其在压缩载荷作用下的破坏机制主要受屈曲控制。微观结构的复杂性、组成材料的多样性以及屈曲行为的复杂性给生物材料屈曲行为的精确预测带来了巨大挑战。本文提出了一种结合有限元分析和机器学习的新方法。具体来说，基于使用有限元法获得的大量数据集，使用机器学习算法快速预测了生物交错复合材料的屈曲强度。在此，系统地研究了微观结构和组件材料对屈曲行为的影响。结果表明，神经网络模型在预测临界屈曲强度方面具有很高的准确性。根据特征重要性分析结果，高宽比和模量比对交错结构的临界屈曲强度有显著影响。此外，交错结构的后屈曲模式对初始几何缺陷表现出更高的敏感性，尤其是在高阶屈曲模式中。我们的研究为快速准确地预测生物复合材料的屈曲行为及其设计提供了宝贵的见解。

Transverse failure prediction of unidirectional carbon fiber reinforced polymer composites subjected to uniaxial and biaxial loading by stress-triaxiality-dependent computational micromechanics

Chenhao Ji, Yunong Zhai, Dongsheng Li, Hao Qu

doi:10.1016/j.compstruct.2024.118359

通过应力-三轴依赖性计算微观力学预测单向碳纤维增强聚合物复合材料在单轴和双轴载荷作用下的横向破坏情况

Accurate characterizing the mechanical behavior of the component materials is crucial for failure predicting of unidirectional carbon fiber reinforced polymer (UD CFRP) composites. A stress-triaxiality-dependent micromechanics model is developed for the transverse failure prediction of the composites in this study, in which the stress triaxiality is innovatively adopted to define the plastic hardening behavior of the matrix material. Therefore, diverse hardening behaviors generated by heterostructures, accurate confirmation of biaxial failure, as well as hardening behavior evolution caused by stress status changes during loading process can be considered. The accuracy performance of the micromechanics model is provided by comparing the predicted results (stress–strain curves, RVE profiles and failure points) with existing experimental data and failure envelopes of failure criterion. The comparison results show that the micromechanics model can accurately capture the failure phenomenon and failure evolution mechanism of the composite under uniaxial and biaxial loadings.

准确表征成分材料的力学行为对于单向碳纤维增强聚合物（UD CFRP）复合材料的失效预测至关重要。本研究为复合材料的横向失效预测开发了一个应力三轴依赖性微观力学模型，其中创新性地采用了应力三轴来定义基体材料的塑性硬化行为。因此，可以考虑异质结构产生的多种硬化行为、双轴失效的准确确认以及加载过程中应力状态变化引起的硬化行为演变。通过比较预测结果（应力-应变曲线、RVE 曲线和失效点）与现有实验数据和失效准则的失效包络线，可以看出微观力学模型的准确性。比较结果表明，微观力学模型能够准确捕捉复合材料在单轴和双轴载荷作用下的失效现象和失效演化机制。

Multi deep learning-based stochastic microstructure reconstruction and high-fidelity micromechanics simulation of time-dependent ceramic matrix composite response

Mohamed H. Hamza, A. Chattopadhyay

doi:10.1016/j.compstruct.2024.118360

基于多重深度学习的随机微结构重构和高保真微观力学模拟随时间变化的陶瓷基复合材料响应

A multi deep learning-based framework is developed for efficient, automated microstructure reconstruction and generation of stochastic representative volume elements (SRVEs) with periodic boundary conditions (PBCs) for accurate modeling of ceramic matrix composite (CMC) response. The methodology comprises a convolutional neural network coupled with regression layers to act as a vanilla regression network for semantic segmentation of the microstructure, allowing accurate characterization of the phases and their distributions at the microscale. Scanning electron microscope and confocal microscope are used to obtain C/SiNC and SiC/SiNC CMCs micrographs for vanilla regression testing. Microstructure variability in terms of fiber volume fraction and porosity are quantified through the output regression layer, ensuring accurate representation of material variability in SRVE construction. Generative adversarial network (GAN) and its variants are designed to produce high-fidelity SRVE, spanning CMCs microstructure variability space. A circular padding algorithm is developed to generate SRVEs with PBCs during training of GANs. The accuracy of the generated SRVEs is established through micromechanics simulations, where an efficient formulation of the high-fidelity generalized methods of cells (HFGMC) approach is used to compute the effective mechanical properties. An iterative algorithm is implemented in the HFGMC solver to simulate time-dependent deformation of SiC/SiNC subjected to creep loading conditions.

本研究开发了一种基于深度学习的多元框架，用于高效、自动地重建微观结构，并生成具有周期性边界条件（PBC）的随机代表体积元素（SRVE），以准确模拟陶瓷基复合材料（CMC）的响应。该方法由卷积神经网络和回归层组成，可作为香草回归网络对微观结构进行语义分割，从而准确表征微观尺度上的相位及其分布。扫描电子显微镜和共聚焦显微镜用于获取 C/SiNC 和 SiC/SiNC CMC 显微图片，以进行 vanilla 回归测试。通过输出回归层对纤维体积分数和孔隙率方面的微观结构变化进行量化，确保在 SRVE 结构中准确表示材料的变化。生成对抗网络（GAN）及其变体旨在生成高保真 SRVE，跨越 CMC 微观结构变化空间。在 GAN 的训练过程中，开发了一种循环填充算法来生成具有 PBC 的 SRVE。通过微观力学模拟确定了生成的 SRVE 的准确性，其中使用了高保真广义单元法 (HFGMC) 方法的有效公式来计算有效力学性能。在 HFGMC 求解器中实施了一种迭代算法，以模拟在蠕变加载条件下 SiC/SiNC 随时间变化的变形。

Non-linear buckling analysis of delaminated hat-stringer panels using variational asymptotic method

A. Phanendra Kumar, Javier Paz Méndez, Ramesh Gupta Burela, Chiara Bisagni, Dineshkumar Harursampath, Sathiskumar Anusuya Ponnusami

doi:10.1016/j.compstruct.2024.118276

使用变异渐近法对分层帽形弦杆面板进行非线性屈曲分析

This research proposes a computationally efficient methodology using a Constrained Variational Asymptotic Method (C-VAM) for non-linear buckling analysis on a hat-stringer panel with delamination defects. Starting with the geometrically non-linear kinematics, the VAM procedure reduces the three-dimensional (3-D) strain energy functional to an analogous 2-D plate model and evaluates the closed form warping solutions. Utilising the resulting warping solutions and recovery relations for the skin and the stringer, displacement continuity at the three-dimensional level is enforced between the stringer and the skin based on the pristine and delaminated interface regions. Consequently, the constrained matrices obtained from C-VAM is incorporated into an in-house developed non-linear finite element framework. Using the developed formulation, a stiffened panel with delamination of 40 mm between the stringer and the skin is analysed under compression. The results have been validated locally and globally, employing experimental data and 3-D finite element analysis (FEA). Experiments are carried out on the co-cured panel by applying quasi-static loading with displacement-controlled conditions, and 3-D FEA is carried out in Abaqus. Load-response plots have been obtained to validate the results at the global level, and they are in excellent agreement with experiments and 3-D FEA. Subsequently, out-of-plane displacement contour plots are obtained; the number of half waves and wave intensity in 3-D FEA and C-VAM are comparable, although there are minor differences compared to the experimental findings. The proposed framework is shown to be computationally efficient by over 55% as compared to 3-D FEA for performing non-linear buckling analysis on the stiffened composite structure considered in the current work.

本研究提出了一种计算效率高的方法，即使用约束变异渐近法（C-VAM）对存在分层缺陷的帽形拉杆面板进行非线性屈曲分析。从几何非线性运动学出发，VAM 程序将三维（3-D）应变能函数简化为类似的 2-D 板模型，并评估闭式翘曲解。利用得到的翘曲解以及表皮和钢绞线的恢复关系，根据原始和分层界面区域，在钢绞线和表皮之间实现三维层面的位移连续性。因此，从 C-VAM 中获得的约束矩阵被纳入了内部开发的非线性有限元框架。利用所开发的公式，分析了加劲板在压缩条件下的情况，加劲板的支柱和表皮之间有 40 毫米的分层。实验数据和三维有限元分析（FEA）对结果进行了局部和全局验证。在共固化面板上进行了实验，施加了具有位移控制条件的准静态加载，并在 Abaqus 中进行了三维有限元分析。获得的载荷响应图验证了全局结果，与实验和三维有限元分析结果非常吻合。随后，获得了平面外位移等值线图；3-D 有限元分析和 C-VAM 中的半波数量和波强具有可比性，尽管与实验结果相比存在细微差别。与三维有限元分析相比，在对当前工作中所考虑的加劲复合材料结构进行非线性屈曲分析时，所提出的框架的计算效率提高了 55% 以上。

Experimental and numerical investigation on crack propagation in biomimetic nacreous composites with gradient structures

Tong Xia, Shaokang Cui, Zhenyu Yang, Zixing Lu

doi:10.1016/j.compstruct.2024.118346

具有梯度结构的仿生珍珠质复合材料裂纹扩展的实验和数值研究

Combining interlocking structures and gradient design, this paper proposes a 2D biomimetic nacreous composite material with a gradient interlocked structure. Experimental and numerical simulation methods are employed to investigate the initiation and propagation behavior of cracks in the regular interlocking and gradient interlocked biomimetic nacre composite materials. Samples of biomimetic nacre composite materials with pre-existing cracks are manufactured using 3D printing technology, and uniaxial tensile tests are conducted to explore their crack propagation behavior. For biomimetic nacreous composite materials with periodic interlocking structures, the interlocking angle is found to play an important role in the toughening mechanism of composites. In biomimetic composite materials with large interlocking angles, crack inhibition effects are achieved through structural gradient design, effectively preventing catastrophic failure. Within the numerical analysis framework, a cohesive zone modeling approach is employed to represent the softer phase of the material, and the numerical simulation are validated by direct comparison with experimental results. In addition, a comprehensive numerical analysis is carried out to comprehend how the structural gradient affects the spread of cracks in these nacreous composites. This research not only illuminate the underlying deformation and toughening mechanisms intrinsic to interlocking nacreous composites but also pave the way for innovative strategies in the design of biomimetic materials through the incorporation of structural gradients.

本文结合交错结构和梯度设计，提出了一种具有梯度交错结构的二维仿生珍珠质复合材料。采用实验和数值模拟方法研究了规则交错和梯度交错生物仿生珍珠质复合材料中裂纹的产生和扩展行为。利用三维打印技术制造了已存在裂纹的仿生珍珠质复合材料样品，并进行了单轴拉伸试验，以探索其裂纹扩展行为。对于具有周期性 交错结构的仿生珍珠质复合材料，研究发现交错角在复合材料的增韧机理中起着重要作用。在具有大交错角的仿生复合材料中，通过结构梯度设计可实现裂纹抑制效果，有效防止灾难性破坏。在数值分析框架内，采用了内聚区建模方法来表示材料的软相，并通过与实验结果的直接对比来验证数值模拟的有效性。此外，还进行了全面的数值分析，以了解结构梯度如何影响这些珍珠质复合材料中裂纹的扩散。这项研究不仅揭示了交错珍珠质复合材料内在的变形和增韧机制，还为通过结合结构梯度设计仿生物材料的创新策略铺平了道路。

X-ray computed tomographyFatigue damage evolution and residual strength analysis of 3D5D braided composites using X-ray tomography, acoustic emission, and digital image correlation

Xiaodong Liu, Jingran Ge, Diantang Zhang, Jun Liang

doi:10.1016/j.compstruct.2024.118348

X 射线计算机断层扫描利用 X 射线断层扫描、声发射和数字图像相关性分析 3D5D 编织复合材料的疲劳损伤演变和残余强度

The accumulation of fatigue damage leads to continuous degradation of the residual strength of three-dimensional braided composites, directly determining the fatigue life. However, the inability to continuously collect residual strength and multiple damage modes pose a challenge to study the residual strength degradation mechanisms of three-dimensional braided composites. In this work, digital image correlation and acoustic emission techniques are employed to assess the strain field and damage events of the specimens during the residual strength tests. X-ray computed tomography facilitates the visualization and quantification of the fatigue damage evolution in three-dimensional braided composites. Moreover, the “two-step” damage classification method is applied to isolate the damage mechanisms. The Pearson correlation analysis is preformed between the quantitative results of three non-destructive techniques and residual strength degradation of 3D braided composites. The integration of the outcomes provides a comprehensive depiction of the residual strength degradation mechanisms.

疲劳损伤的积累会导致三维编织复合材料的残余强度不断退化，从而直接决定其疲劳寿命。然而，无法连续采集残余强度和多种损伤模式给研究三维编织复合材料的残余强度退化机制带来了挑战。在这项工作中，采用了数字图像相关技术和声发射技术来评估残余强度测试期间试样的应变场和损伤事件。X 射线计算机断层扫描技术有助于对三维编织复合材料的疲劳损伤演变进行可视化和量化。此外，还采用了 "两步 "损伤分类法来隔离损伤机制。三种非破坏性技术的定量结果与三维编织复合材料的残余强度退化之间预先进行了皮尔逊相关分析。这些结果的整合提供了对残余强度退化机制的全面描述。

Intra-yarn fibre hybridisation effect on homogenised elastic properties and micro and meso-stress analysis of 2D woven laminae: Two-scale FE model

Nenglong Yang, Zhenmin Zou, Prasad Potluri, Constantinos Soutis, Kali Babu Katnam

doi:10.1016/j.compstruct.2024.118358

纱内纤维杂化对二维编织层板的均质弹性特性以及微观和中观应力分析的影响：双尺度 FE 模型

In this paper, the effect of intra-yarn fibre hybridisation on the homogenised elastic properties and micro- and meso-scale matrix stress fields in 2D woven composite laminae (i.e. plain, 2/2 basket, 2/2 twill and 5-harness satin) is studied with a two-scale homogenisation scheme—employing a representative volume element model at micro-scale and a repeating unit cell model at meso-scale. The study is focused on S-glass/polypropylene/epoxy woven laminae with intra-yarn fibre hybridisation. A modified random sequential expansion algorithm generates microstructure for the micro-mechanical model, and a periodic meso-structure is used to generate the weave architecture for the meso-mechanical model. Both models are verified using analytical models. It is found that intra-yarn fibre hybridisation can significantly alter the homogenised properties as well as the micro- and meso-scale matrix stress fields—depending on the degree of hybridisation (i.e. the combination of S-glass and PP fibre volume fractions). Moreover, the homogenised lamina properties are found to be less sensitive to weave architecture and yarn thickness, but more so to the degree of intra-yarn fibre hybridisation, yarn width and yarn spacing. It is shown that the lamina properties can be tailored, and the micro- and meso-stress fields can be manipulated, by intra-yarn fibre hybridisation and weave architectures

本文采用双尺度均匀化方案研究了纱内纤维杂化对二维编织复合材料层压板（即平纹、2/2 篮纹、2/2 斜纹和 5 哈丝缎纹）的均匀化弹性特性以及微观和中观尺度基体应力场的影响--在微观尺度上采用代表性体积元素模型，在中观尺度上采用重复单元格模型。研究重点是具有纱内纤维杂化的 S 玻璃/聚丙烯/环氧编织层织物。微观力学模型采用改进的随机顺序扩展算法生成微观结构，中观力学模型采用周期性中观结构生成编织结构。这两个模型都通过分析模型进行了验证。研究发现，纱内纤维杂化会显著改变均匀化特性以及微观和中观尺度基体应力场--取决于杂化程度（即 S 玻璃纤维和 PP 纤维体积分数的组合）。此外，研究还发现，均匀化薄层特性对编织结构和纱线厚度的敏感度较低，但对纱线内纤维杂化程度、纱线宽度和纱线间距的敏感度较高。结果表明，通过纱内纤维杂化和编织结构，可以定制薄片特性，并操纵微应力场和中应力场。

Composites Part A: Applied Science and Manufacturing

Enhanced carbon black exfoliation through elongational flows for faster and higher value-added rubber recycling

He Zhang, Xiangyang Li, Xiaochun Yin

doi:10.1016/j.compositesa.2024.108343

 

通过拉伸流强化炭黑剥离，实现更快、更高附加值的橡胶回收利用

The recycling of rubber featuring intricate three-dimensional crosslinked networks necessitates the application of cutting-edge technology and specialized machinery. In this study, the rubber was recycled by mechanochemistry under elongational flow field. The crosslink bonds in the rubber were rapidly broken through the high extension of molecular chains, without the need for additives or additional refinements. At 200 °C, the waste rubber is devulcanized in only 2 min so that the sol molecular weight reached an impressive 3.3 × 104 g/mol, and the mechanical properties of the reclaimed rubber were significantly enhanced, reaching a tensile strength of 17.44 MPa. The elongational flow field devulcanizes the waste rubber while simultaneously achieving rapid refinement of rubber particles and exfoliating the carbon black from the crosslinked network. These making reclaimed rubber forms a micro-nano microstructure in natural rubber (NR), which makes particle reinforcement of the NR-matrix. Faster and high-value-added rubber recycling achieved successfully through elongational flows.

回收具有复杂三维交联网络的橡胶需要应用尖端技术和专业机械。在这项研究中，橡胶是在拉伸流场下通过机械化学方法回收的。通过分子链的高度延伸，橡胶中的交联键迅速断裂，无需添加剂或额外的精炼。在 200 °C 的温度下，废橡胶仅在 2 分钟内就完成了脱硫化，使溶胶分子量达到了惊人的 3.3 × 104 g/mol，再生橡胶的机械性能显著提高，拉伸强度达到了 17.44 MPa。拉伸流场使废橡胶脱硫，同时实现了橡胶颗粒的快速细化，并使炭黑从交联网络中剥离。这些再生橡胶在天然橡胶（NR）中形成了微纳米微结构，从而使 NR 基质得到颗粒强化。通过拉伸流动，成功实现了更快和高附加值的橡胶回收。

The electrical conductivity mechanism of Graphene/Copper composite fabricated by one-step pulsed electrodeposition

Jiani Yu, Lidong Wang, Yekang Guan, Bin Shao, Yingying Zong

doi:10.1016/j.compositesa.2024.108345

一步脉冲电沉积法制备的石墨烯/铜复合材料的导电机理

Copper plays a key role in electronics, energy, and so on. However, copper faces the challenge of increasing resistivity with increasing temperature. To overcome this problem, graphene was introduced into copper to prepare graphene/copper (Gr/Cu) composites. Here, we report on the preparation of Gr/Cu-Cu wires and Gr/Cu foil by pulse electrodeposition (P-EP). The electrical conductivity of the Gr/Cu foil was 3.8 % IACS higher than that of pure Cu foil under 180 °C. Graphene plays a crucial role in providing an electron transfer path in the Gr/Cu composite to improve the electrical conductivity under high temperatures. The P-EP process can not only effectively reduce the raw GO, but also introduce nitrogen into graphene which further promotes the transfer of electrons from copper to graphene. These results suggest that Gr/Cu composites have promising prospects for applications at high temperatures and could potentially replace traditional pure Cu.

铜在电子、能源等领域发挥着重要作用。然而，铜面临着电阻率随温度升高而增大的挑战。为了克服这一问题，人们将石墨烯引入铜中，制备出石墨烯/铜（Gr/Cu）复合材料。在此，我们报告了通过脉冲电沉积（P-EP）制备石墨烯/铜线和石墨烯/铜箔的情况。在 180 °C 下，Gr/Cu 箔的导电率比纯铜箔高 3.8 % IACS。在 Gr/Cu 复合材料中，石墨烯在提供电子转移路径以提高高温下的导电性方面发挥了关键作用。P-EP 工艺不仅能有效减少原始 GO，还能将氮引入石墨烯，从而进一步促进电子从铜转移到石墨烯。这些结果表明，Gr/Cu 复合材料在高温下具有广阔的应用前景，有可能取代传统的纯铜。

Covalent bond-assisted continuous interface structure for high thermal conductive polyimide composite films

Fan Wang, Xiaodi Dong, Guangyi Liu, Baoquan Wan, Jinghui Gao, Baixin Liu, Jun-Wei Zha

doi:10.1016/j.compositesa.2024.108348

高导热聚酰亚胺复合薄膜的共价键辅助连续界面结构

Polyimide (PI) is widely used in electronic, electrical and communication fields because of its outstanding mechanical properties, electrical insulation and thermal stability. However, the lower thermal conductivity limits their application. Here, PI composite films with high thermal conductivity are obtained by utilizing reactive groups on the carbon nitride nanosheets (CNNS) surface to form covalent bond with PI matrix. The thermal conductivity of CNNS/PI composite films can reach 5.84 W∙m−1∙K−1, which is about 10 times higher than that of pure PI (0.56 W∙m−1∙K−1). This is attributed to the covalent bond between CNNS and PI matrix acting as a “thermal bridge” to connect the discontinuities at the interface, thereby reducing the interfacial thermal resistance between CNNS and PI. The heat transfer mechanism of composite film is further revealed by finite element analysis. This work provides a viable solution to improve the thermal conductivity of PI, allowing for a wide range of potential applications for PI in electronic devices.

聚酰亚胺（PI）具有出色的机械性能、电绝缘性和热稳定性，因此被广泛应用于电子、电气和通信领域。然而，较低的热导率限制了其应用。在这里，通过利用氮化碳纳米片（CNNS）表面的反应基团与 PI 基体形成共价键，获得了具有高导热性的 PI 复合薄膜。CNNS/PI 复合薄膜的导热系数可达 5.84 W∙m-1∙K-1 ，是纯 PI（0.56 W∙m-1∙K-1 ）的 10 倍。这是由于 CNNS 和 PI 基体之间的共价键起到了 "热桥 "的作用，连接了界面上的不连续性，从而降低了 CNNS 和 PI 之间的界面热阻。有限元分析进一步揭示了复合薄膜的传热机制。这项研究为提高 PI 的热导率提供了一种可行的解决方案，使 PI 在电子设备中的应用前景更加广阔。

Fast approximation of fiber reinforced injection molding processes using eikonal equations and machine learning

Julian Greif, Philipp Lechner, Nils Meyer

doi:10.1016/j.compositesa.2024.108340

利用 Eikonal 方程和机器学习快速逼近纤维增强注塑成型工艺

Injection molding is a popular production process for short fiber reinforced components. The mechanical properties of such components depend on process-induced fiber orientations which are commonly predicted via numerical simulations. However, high computational costs prevent process simulations from being used in iterative procedures, such as topology optimization or finding optimal injection locations. We propose a fast approximation method that extracts nodal features and train a regression model to predict fill states, cooling times, volumetric shrinkage, and fiber orientations. The features are determined by solving eikonal equations with a fast iterative method and computing spatial moments to characterize node-adjacent material distributions. Subsequently, we use these features to train feed forward neural networks and gradient boosted regression trees with simulation data of a large dataset of geometries. This approach is significantly faster than conventional methods, providing 20x speed-up for single simulations and more than 200x speed-up in gate location optimization. It generalizes to arbitrary geometries and injection locations.

注塑成型是短纤维增强部件的常用生产工艺。此类部件的机械性能取决于工艺引起的纤维取向，通常通过数值模拟进行预测。然而，由于计算成本高昂，工艺模拟无法用于拓扑优化或寻找最佳注塑位置等迭代程序。我们提出了一种快速近似方法，通过提取节点特征和训练回归模型来预测填充状态、冷却时间、体积收缩率和纤维方向。通过使用快速迭代法求解 eikonal 方程并计算空间矩来确定节点相邻材料分布的特征。随后，我们利用这些特征来训练前馈神经网络和梯度提升回归树，并使用大量几何数据集的模拟数据。这种方法明显快于传统方法，单次模拟速度提高了 20 倍，栅极位置优化速度提高了 200 倍以上。该方法还适用于任意几何形状和注入位置。

Composites Part B: Engineering

Supersonic Hot Jet Ablative Testing and Analysis of Boron Nitride Nanotube Hybrid Composites

Aspen N. Reyes, Yousef Saleh, Jonas Gustavsson, Claire N. Jolowsky, Rajan Kumar, LaRico J. Treadwell, Rebekah D. Sweat

doi:10.1016/j.compositesb.2024.111684

氮化硼纳米管混合复合材料的超音速热喷射烧蚀测试与分析

Boron nitride nanotubes (BNNTs) are high-strength, high-modulus nanotubes with high thermal and oxidative stabilities. Two hybrid composites were prepared with satin weave CF and resole-type phenolic resin: one with surface layers of BNNTs and one with alternating interlayers of BNNTs. The samples were subjected to hot jet tests that simulate realistic high-pressure-temperature conditions to understand the behavior of BNNTs under high-pressure erosion. Adding BNNTs to CF/phenolic laminates enhanced the ablation resistance by reinforcing the char material and mitigated localized thermal damage. Hybrid laminates exhibited up to 14% lower weight loss, 55% increase in flexural modulus, higher thermal diffusivity, and improved char yield and microstructure compared to CF/phenolic samples. The surface layer hybrid had many surviving nanotubes reinforcing the char and crystalline oxide structures that could mitigate further oxygen diffusion. Various characterization methods were used to deduce possible mechanisms and their products, indicating that BNNTs could serve as growth templates for direct crystalline boron oxide formation. Overall, hybrid BNNT/CF/phenolic laminates displayed better ablation resistance and favorable microstructure evolution under high-pressure conditions.

氮化硼纳米管（BNTs）是一种高强度、高模量的纳米管，具有很高的热稳定性和氧化稳定性。我们用缎纹编织 CF 和树脂型酚醛树脂制备了两种混合复合材料：一种具有 BNNTs 表层，另一种具有 BNNTs 交替夹层。对样品进行了模拟真实高温高压条件的热喷射试验，以了解 BNNT 在高压侵蚀下的行为。将 BNNTs 添加到 CF/酚醛层压板中可增强炭材料的抗烧蚀性，并减轻局部热损伤。与 CF/酚醛样品相比，混合层压板的重量损失降低了 14%，弯曲模量增加了 55%，热扩散率更高，炭产量和微观结构也得到了改善。表层混合材料有许多存活的纳米管，可强化炭和结晶氧化物结构，从而减少氧气的进一步扩散。使用各种表征方法推断了可能的机制及其产物，表明 BNNT 可作为直接形成结晶氧化硼的生长模板。总之，在高压条件下，BNNT/CF/酚醛混合层压板显示出更好的耐烧蚀性和有利的微观结构演化。

Flexibility, Toughness, and Load Bearing of 3D-Printed Chiral Kerf Composite Structures

Aryabhat Darnal, Kanak Mantri, Will Betts, Negar Kalantar, Jeeeun Kim, Anastasia Muliana

doi:10.1016/j.compositesb.2024.111685

 

三维打印手性角复合结构的柔韧性、韧性和承载力

Chiral kerf structures are formed by arranging chiral and coiled unit cells which allows for multi-dimensional and multi-scale shape configurations under mechanical loadings. In this study, we investigate how the mechanical properties of materials and microstructural topologies interact to control the flexibility, toughness, and load bearing of 3D-printed chiral kerf structures. We explore chiral kerf structures with two different kerf patterns, i.e., square and hexagon, and three coiling densities. We consider three materials, namely brittle Polylactic Acid (PLA), compliant thermoplastic polyurethane (TPU), and a ductile composite made by alternating PLA and TPU, referred to as a programmable composite. The chiral kerf structures undergo two deformation mechanisms when subjected to mechanical loadings. The first one results from reconfigurations of kerf cells such as uncoiling, rotation of cells, and cell packing, and the second mechanism arises from nonlinear and inelastic material responses. The use of brittle material limits cell reconfigurations before material failure, reducing the overall flexibility and toughness of kerf structures. While the compliant material enables full cell reconfigurations, it results in low load bearing. The use of PLA:TPU composite allows for cell reconfigurations and inelastic material response, enhancing flexibility and toughness while maintaining a relatively high load bearing. We demonstrate that stress distribution in kerf structures can be controlled by using multiple materials or coil densities. This strategy can delay failure and improve the toughness and load-bearing capabilities of kerf structures.

手性切口结构是通过排列手性和盘绕单元格形成的，可在机械载荷作用下实现多维和多尺度的形状配置。在本研究中，我们探讨了材料的机械性能和微结构拓扑如何相互作用，以控制 3D 打印手性切口结构的柔韧性、韧性和承载力。我们探索了具有两种不同切口模式（即正方形和六边形）和三种卷绕密度的手性切口结构。我们考虑了三种材料，即脆性聚乳酸（PLA）、顺应性热塑性聚氨酯（TPU）以及由聚乳酸和热塑性聚氨酯交替制成的韧性复合材料（称为可编程复合材料）。手性切口结构在承受机械载荷时会发生两种变形机制。第一种变形机制源于切口单元的重新配置，如开卷、单元旋转和单元包装；第二种机制源于材料的非线性和非弹性反应。脆性材料的使用限制了材料失效前的单元重新配置，降低了切口结构的整体灵活性和韧性。虽然顺应性材料能够实现全面的单元重新配置，但却导致承载力较低。使用聚乳酸：热塑性聚氨酯（PLA:TPU）复合材料可实现单元重新配置和非弹性材料响应，在保持相对较高承载力的同时增强了灵活性和韧性。我们证明，可以通过使用多种材料或线圈密度来控制切口结构中的应力分布。这种策略可以延缓失效，提高切口结构的韧性和承载能力。

Enhanced Multifunctionality in Carbon Fiber/Carbon Nanotube Reinforced PEEK Hybrid Composites: Superior Combination of Mechanical Properties, Electrical Conductivity, and EMI Shielding

Mitesh Patadia, Anthony Quinn, Mehul Tank, Claire Jolowsky, Lima Luiz, Anthony Psulkauski, Matthew Kurilich, Ana De Leon, Richard Liang, Rebekah Sweat

doi:10.1016/j.compositesb.2024.111674

增强碳纤维/碳纳米管增强聚醚醚酮（PEEK）混合复合材料的多功能性：机械性能、导电性和 EMI 屏蔽的完美结合

This study presents a novel approach to manufacturing carbon fiber and carbon nanotube-reinforced PEEK hybrid composites (CF/CNT/PEEK) using compression molding. The hybrid composite characteristics were compared with those of a control composite (CF/PEEK). Various tests were conducted on both composite types to investigate the impact of incorporating a carbon nanotube sock layer (an ultra-thin layer of a low-density CNT network), including three-point bend, electrical conductivity, and EMI shielding. The research also underscored the importance of EMI shielding simulation. An important aspect of the study involved performing multiscale simulations on control and hybrid composites, employing a digital twin methodology, and validating the results with experimental findings. For the hybrid composite, double multiscale simulations were performed by integrating two local-scale models, a CF/PEEK unit cell (micro-scale) and a CNT/PEEK representative volume element (RVE) (nano-scale), into a global-scale model. A detailed post-processing analysis of the simulation results was conducted to analyze stress distribution on local and global scale models. It was noted that there was an over 8% increase in the flexural strength of the hybrid composite, along with a reduction of over 27% in the standard deviation of the results. The introduction of CNTs enhanced the electrical conductivity by more than 36%. It conferred remarkable EMI shielding effectiveness exceeding 50 dB across the entire X-band frequency range, attributed to enhanced reflection and absorption. EMI shielding simulations suggest that refining the manufacturing process of the hybrid composite could enhance its shielding properties. The developed multiscale simulation has been demonstrated as an efficient prediction tool, as the simulation outcomes closely align with experimental findings. The resultant hybrid composite is promising for potential multifunctional applications.

本研究提出了一种利用压缩成型制造碳纤维和碳纳米管增强聚醚醚酮（PEEK）混合复合材料（CF/CNT/PEEK）的新方法。混合复合材料的特性与对照复合材料（CF/PEEK）的特性进行了比较。对这两种类型的复合材料进行了各种测试，以研究加入碳纳米管袜子层（低密度碳纳米管网络的超薄层）的影响，包括三点弯曲、导电性和 EMI 屏蔽。研究还强调了 EMI 屏蔽模拟的重要性。研究的一个重要方面是采用数字孪生方法对控制复合材料和混合复合材料进行多尺度模拟，并将结果与实验结果进行验证。对于混合复合材料，通过将 CF/PEEK 单元尺寸（微尺度）和 CNT/PEEK 代表体积元素 (RVE)（纳米尺度）这两个局部尺度模型集成到一个全局尺度模型中，进行了双重多尺度模拟。对模拟结果进行了详细的后处理分析，以分析局部和全局模型上的应力分布。结果表明，混合复合材料的抗弯强度提高了 8%以上，结果的标准偏差降低了 27%以上。引入碳纳米管后，导电率提高了 36% 以上。由于增强了反射和吸收，它在整个 X 波段频率范围内的电磁干扰屏蔽效果显著，超过了 50 dB。EMI 屏蔽模拟表明，改进混合复合材料的制造工艺可以提高其屏蔽性能。所开发的多尺度模拟已被证明是一种高效的预测工具，因为模拟结果与实验结果非常吻合。由此产生的混合复合材料具有潜在的多功能应用前景。

Improvement of Silicon and Epoxy Phase Interface by Constructing Rigid Interpenetrating Networks Based on Bismaleimide to Enhance Ablative, Mechanical and Thermal Properties

Youquan Ling, Baowei Qiu, Xue Lei, Lu Shen, Hui Jin, Xi Zhang, Mei Liang, Yang Chen, Huawei Zou

doi:10.1016/j.compositesb.2024.111675

通过构建基于双马来酰亚胺的刚性互穿网络改善硅与环氧树脂相界面，从而提高烧蚀、机械和热性能

Polysiloxanes are widely used in the preparation of ablative-resistant resins due to their tailored reactivity and ceramisable properties. Nevertheless, the mechanical and thermal properties may be negatively impacted by the presence of flexible chain segments and poor compatibility. In this study, the phase interface of silicon between epoxy was improved by a rigid interpenetrating crosslinked network constructing by bismaleimide. The pyrolysis of the silicone was inhibited and the oxidation resistance of the resin was enhanced. Both graphitization and ceramisation of the char layer during ablation are significantly improved. This endows the modified resin with outstanding ablative properties, with mass and linear ablation rates reduced to 0.0666 g/s and 0.0512 mm/s, respectively, which exceed those of some conventional ablative-resistant resins. Remarkably, the thermal and mechanical properties are significantly enhanced benefiting from the rigid crosslinked network and improved phase interfaces. Moreover, the destruction of mechanical properties of composites in high temperature environments caused by organosilicones has been effectively addressed. Bismaleimide/silicone co-modified epoxy resins can be used not only as ablative-resistant coatings, but also for the preparation of fire-resistant carbon fibre composites, providing a novel approach to the production of cost-effective, recyclable structural integrated materials for thermal protection.

聚硅氧烷具有定制的反应性和可陶瓷化的特性，因此被广泛用于制备耐烧蚀树脂。然而，柔性链段的存在和较差的兼容性可能会对其机械性能和热性能产生负面影响。在这项研究中，双马来酰亚胺构建的刚性互穿交联网络改善了硅与环氧树脂之间的相界面。硅的热分解受到抑制，树脂的抗氧化性得到增强。在烧蚀过程中，炭层的石墨化和陶瓷化均得到显著改善。这使得改性树脂具有出色的烧蚀性能，其质量烧蚀率和线性烧蚀率分别降低到 0.0666 克/秒和 0.0512 毫米/秒，超过了一些传统的耐烧蚀树脂。值得注意的是，得益于刚性 交联网络和相界面的改善，热性能和机械性能都得到了显著提高。此外，有机硅对高温环境下复合材料机械性能的破坏问题也得到了有效解决。双马来酰亚胺/有机硅共改性环氧树脂不仅可用作耐烧蚀涂料，还可用于制备耐火碳纤维复合材料，为生产具有成本效益、可回收的热防护结构集成材料提供了一种新方法。

Two-scale asymptotic homogenization analysis of piezoelectric composite materials in generalized curvilinear coordinates

David Guinovart, Mriganka Shekhar Chaki, Raúl Guinovart-Díaz

doi:10.1016/j.compositesb.2024.111677

广义曲线坐标下压电复合材料的双尺度渐近均质分析

This paper presents a comprehensive study on applying the two-scale asymptotic homogenization method to derive the effective properties of piezoelectric composite materials characterized by generalized periodicity in curvilinear coordinates. The methodology involves formulating the homogenization problem in a general curvilinear framework suitable for materials with complex geometric configurations. By systematically deriving the homogenized equations and effective coefficients, the paper provides a robust theoretical foundation for understanding the macroscopic behavior of piezoelectric composites under various loading conditions. The model’s versatility is demonstrated through its application to specific curvilinear coordinate systems, including the helix coordinate system and cylindrical coordinates with wavy geometry. These examples highlight the potential of the proposed approach in analyzing and designing piezoelectric materials with intricate geometries. The state-of-the-art numerical homogenization methods have also validated the proposed homogenization method, ensuring its accuracy and robustness.

本文全面研究了如何应用双尺度渐近均质化方法推导压电复合材料的有效特性，该材料在曲线坐标中具有广义周期性特征。该方法涉及在一个适合具有复杂几何构型的材料的一般曲线框架中制定均质化问题。通过系统地推导均质化方程和有效系数，本文为理解压电复合材料在各种加载条件下的宏观行为提供了坚实的理论基础。该模型在特定曲线坐标系（包括螺旋坐标系和具有波浪形几何形状的圆柱坐标系）中的应用证明了它的多功能性。这些例子凸显了所提出的方法在分析和设计具有复杂几何形状的压电材料方面的潜力。最先进的数值均质化方法也验证了所提出的均质化方法，确保了其准确性和稳健性。

Lamellar structure of high-strength direct-spun CNT yarns: Implications for interface failure

Ibrahim Guven, Mark Lauer, Carl Mayer

doi:10.1016/j.compositesb.2024.111690

 

高强度直纺 CNT 纱的层状结构：对界面失效的影响

A previously unreported nanoscale lamella structure in a direct spun high strength carbon nanotube (CNT) yarn was identified and characterized. The thickness of the lamellae is in the order of 100 nm. The lamella structure is present in the entire cross-section. It is hypothesized that the lamella structure originates from a single thin sheet (felt) during the manufacturing process, between steps of CNT aerogel and CNT roving. The existence of this lamella structure has direct implications on the yarn-resin interface behavior of derived composites and, subsequently, the mechanical performance of CNT yarn composites. Peridynamic simulations of four distinct yarn pullout experiments captured the observed failure behavior influenced by microstructure.

在直接纺制的高强度碳纳米管（CNT）纱线中发现了一种以前未报道过的纳米级薄片结构，并对其进行了表征。薄片的厚度约为 100 纳米。薄片结构存在于整个横截面上。据推测，这种薄片结构是在制造过程中，在碳纳米管气凝胶和碳纳米管粗纱两个步骤之间的单层薄片（毡）上产生的。这种薄片结构的存在直接影响到衍生复合材料的纱线-树脂界面行为，进而影响到 CNT 纱线复合材料的机械性能。四种不同纱线拉拔实验的周动态模拟捕捉到了观察到的受微观结构影响的失效行为。

Composites Science and Technology

High-temperature wave-transparent and intrinsically flame-retardant phthalonitrile/quartz composite based on a straightforward hot-melt prepreg process

Yabin Zhang, Linyan Zhu, Jiaming Wang, Xuedong Wu, Wenhua Hou, Lishuai Zong, Jinyan Wang, Xigao Jian

doi:10.1016/j.compscitech.2024.110742

 

基于直接热熔预浸料工艺的高温透波和本征阻燃邻苯二腈/石英复合材料

Wave-transparent composite materials are becoming increasingly critical for advancing robust human-machine interaction systems. A pivotal component of these systems is an organic resin matrix, which is currently the focus of intensive research. Herein, to develop a phthalonitrile resin capable of withstanding temperatures exceeding 500 °C, two types of Si/P-containing alkynyl curing agents (Si-ALK and P-ALK) were synthesized and integrated with sulfur-enriched phthalonitrile monomers (SSS-PN) to fabricate an organic-inorganic hybrid phthalonitrile（PN）resin. The resulting hybrid resin demonstrated exceptional thermal stability (594 °C for 10% Si-PN-450 °C; 626 °C for 50% P-PN-450 °C) and thermal oxygen stability (569 °C for 10% Si-PN-450 °C; 594 °C for 30% P-PN-450 °C). The Si-ALK/P-ALK and SSS-PN blends maintained stable low-viscosity properties for an extended period of up to 180 min, which is advantageous for the facile production of quartz fiber-infused composites (Si-PN/QF and P-PN/QF) through a straightforward and eco-friendly melt processing approach. The cured PN composite (30% Si-PN-450 °C/QF vs. 10% P-PN-450 °C/QF) exhibited significantly improved glass transition temperatures (506 °C vs. 553 °C), acceptable flexural strength (268 MPa vs. 275 MPa), and excellent flame retardancy (less than 8.0% weight loss exposed at 1300 °C for 200 s). Additionally, the composites demonstrated commendable dielectric properties, with a dielectric constant (Dk) of approximately 4.0 and a dissipation factor (Df) below 0.01 from 25 °C to 600 °C. Collectively, the obtained composites exhibited a synergistic combination of thermal, fire-resistant, and dielectric properties, positioning them as leading candidates for the next generation of wave-transparent materials.

透波复合材料对于推进稳健的人机交互系统越来越重要。这些系统的一个关键组成部分是有机树脂基体，这也是目前深入研究的重点。在本文中，为了开发一种能够耐受超过500 ℃高温的酞腈树脂，合成了两种含Si/P的炔基固化剂（Si-ALK和P-ALK），并将其与富硫酞腈单体（SSS-PN）结合，制成了一种有机-无机混合酞腈（PN）树脂。制得的杂化树脂具有优异的热稳定性（10% Si-PN-450 ℃时为594 ℃；50% P-PN-450 ℃时为626 ℃）和热氧稳定性（10% Si-PN-450 ℃时为569 ℃；30% P-PN-450 ℃时为594 ℃）。Si-ALK/P-ALK 和 SSS-PN 混合物可在长达 180 分钟的时间内保持稳定的低粘度特性，这有利于通过直接、环保的熔融加工方法轻松生产石英纤维注入复合材料（Si-PN/QF 和 P-PN/QF）。固化后的 PN 复合材料（30% Si-PN-450 ℃/QF 与 10% P-PN-450 ℃/QF）的玻璃化转变温度（506 ℃ 与 553 ℃）、抗弯强度（268 兆帕与 275 兆帕）和阻燃性（在 1300 ℃ 下暴露 200 秒，重量损失小于 8.0%）均有显著提高。此外，复合材料还具有值得称赞的介电性能，介电常数 (Dk) 约为 4.0，从 25 °C 到 600 °C 的耗散因子 (Df) 低于 0.01。总之，所获得的复合材料展现了热性能、耐火性能和介电性能的协同组合，使其成为下一代透波材料的主要候选材料。