【新文速递】2023年10月14日复合材料SCI期刊最新文章

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今日更新：Composite Structures 1 篇，Composites Part A: Applied Science and Manufacturing 2 篇，Composites Part B: Engineering 1 篇，Composites Science and Technology 2 篇

Composite Structures

Numerical modeling thermo-hygro-mechanical coupling of cross-ply laminate composites using a nonlocal discrete approach

Liu Donglai, Chen Hailong

doi:10.1016/j.compstruct.2023.117618

采用非局部离散方法对交叉层压复合材料的热-湿-机械耦合进行数值建模

Laminate composites are widely used in various industrial applications and are frequently subject to extreme temperature and moisture environment. This paper presents numerical modeling thermo-hygro-mechanical coupling of cross-ply laminate composites using a nonlocal discrete approach formulated based on the local continuum mechanics theory. In the developed model, the material domain is modeled as an assembly of regularly packed material particles whose interaction with neighboring material particles via bonds is nonlocal. Bond parameters are derived based on equivalency of energy and diffusing material transfer rate between the discrete descriptions and their continuum counterparts. The orthotropy of material properties is modeled using rotation of discretization lattice rather than the coordinate transformation that used in the local continuum mechanics theory. The interface and its effect on the material response is investigated by assigning different parameters to bond straddling different material phases. Numerical verification using single and four-ply laminate composites shows excellent accuracy of the developed model.

层压复合材料广泛应用于各种工业领域，经常受到极端温度和湿度环境的影响。本文采用基于局部连续介质力学理论的非局部离散方法，对交叉层压复合材料的热-湿-力学耦合进行数值建模。在所建立的模型中，材料域被模拟为规则排列的材料颗粒的集合体，这些材料颗粒通过键与相邻材料颗粒的相互作用是非局部的。键参数是根据离散描述和连续描述之间能量和扩散材料转移率的等效性推导出来的。材料特性的正交性是通过离散晶格的旋转而不是局部连续介质力学理论中使用的坐标变换来模拟的。通过为跨越不同材料相的键分配不同的参数，研究了界面及其对材料响应的影响。使用单层和四层层压复合材料进行的数值验证表明，所开发的模型具有极佳的准确性。

Composites Part A: Applied Science and Manufacturing

Enhancement of Flexural Properties of Carbon Fiber-Reinforced Polyamide 6 via Oriented Crystallization of Polyamide 6 among Carbon Fibers

Uematsu Hideyuki, Ishikawa Maya, Yamaguchi Ayaka, Sugihara Shinji, Nishitsuji Shotaro, Nishimura Fumihiro, Yamane Masachika, Kawabe Kazumasa, Ozaki Yukihiro, Tanoue Shuichi

doi:10.1016/j.compositesa.2023.107837

通过碳纤维间聚酰胺 6 的定向结晶提高碳纤维增强聚酰胺 6 的挠曲性能

The effect of the crystalline structure of polyamide 6 (PA6) among carbon fiber (CF) on the mechanical properties of PA6/CF composites was explored using two types of PA6 with different spherulite sizes. Infrared (IR) spectroscopy showed that intra/intermolecular interactions were nearly equivalent for the two types of PA6. The viscoelasticities in the molten state were almost identical; that is, the molecular weights of the PA6s were comparable. The mechanical properties of the PA6 matrix with smaller spherulites (PA6a) in PA6/CF were superior to those of the PA6 matrix with larger spherulites (PA6b). Polarized light microscopy, wide-angle X-ray scattering, and polarized Raman spectroscopy revealed oriented crystals of PA6a in the PA6a/CF composite and random crystals of PA6b in the PA6b/CF composite. Therefore, the superior mechanical properties of PA6/CF are due to the oriented crystal chains of PA6, which support the overall stress transfer in composites.

研究人员使用两种不同球粒尺寸的聚酰胺 6（PA6），探讨了碳纤维（CF）中聚酰胺 6（PA6）的结晶结构对 PA6/CF 复合材料机械性能的影响。红外光谱（IR）显示，两种 PA6 的分子内/分子间相互作用几乎相同。熔融状态下的粘弹性几乎相同，即 PA6 的分子量相当。PA6/CF 中球泡较小的 PA6 基质（PA6a）的机械性能优于球泡较大的 PA6 基质（PA6b）。偏光显微镜、广角 X 射线散射和偏振拉曼光谱显示 PA6a/CF 复合材料中的 PA6a 为定向晶体，而 PA6b/CF 复合材料中的 PA6b 为无规晶体。因此，PA6/CF 的优异机械性能是由于 PA6 的取向晶链支持了复合材料中的整体应力传递。

A meso-scale stochastic model for tensile behavior of 2D woven ceramic composites considering void defects and stacking mode

Li Yihang, Ma Yong, Guan Tianhao, Wang Zhen, Zhang Chao, Suo Tao

doi:10.1016/j.compositesa.2023.107838

考虑空隙缺陷和堆叠模式的二维编织陶瓷复合材料拉伸行为中尺度随机模型

A sophisticated meso-scale model is developed based on finite element method to study the tensile failure behavior of 2D-SiCf/SiC. To this end, a thoroughgoing characterization was carried out using SEM and micro-CT to obtain the microstructural parameters, and a progressive damage model related to matrix cracking was proposed for fiber tows to depict the matrix brittleness, an essential feature of ceramic matrix composites. Thereby, a sophisticated model comprehensively incorporating void defects, layer shifts and the damage induced by matrix cracking was established. Elaborate experimental tests including digital image correlation, acoustic emission (AE) and high-speed observation were synthetically conducted to validate this model, and results indicated that this model could provide an accurate prediction. Especially, micro and meso-scale damage modes were identified and the damage process was thoroughly analyzed by combing this model and AE technology. The numerical studies were then implemented to evaluate the effect of stacking mode and porosity.

基于有限元方法开发了一个复杂的中尺度模型，用于研究二维碳化硅/碳化硅的拉伸破坏行为。为此，利用扫描电镜和显微计算机断层扫描进行了全面的表征，以获得微观结构参数，并针对纤维束提出了与基体开裂相关的渐进式损伤模型，以描述基体脆性这一陶瓷基复合材料的基本特征。因此，建立了一个综合了空隙缺陷、层移和基体开裂引起的损伤的复杂模型。为了验证该模型，还进行了包括数字图像相关性、声发射（AE）和高速观测在内的详细实验测试，结果表明该模型可以提供准确的预测。特别是通过将该模型与声发射技术相结合，确定了微观和中观尺度的损伤模式，并对损伤过程进行了深入分析。随后进行了数值研究，以评估堆积模式和孔隙率的影响。

Composites Part B: Engineering

Exploring the piezoresistive sensing behaviour of ultra-high performance concrete: Strategies for multiphase and multiscale functional additives and influence of electrical percolation

Song Facheng, Chen Qing, Zhang Mingzhong, Jiang Zhengwu, Ding Wenqi, Yan Zhiguo, Zhu Hehua

doi:10.1016/j.compositesb.2023.111042

探索超高性能混凝土的压阻传感行为：多相和多尺度功能添加剂的策略以及电渗流的影响

Self-sensing ultra-high performance concrete (UHPC) features superior mechanical capacity, excellent erosion resistance, long life cycle, and broad range of stress sensing, and is expected to be a pathway towards next-generation smart cementitious composites. This study presents a novel strategy to achieve electrical percolation and elevate the piezoresistive sensing capability of UHPC through the incorporation of multiphase and multiscale functional additives including graphene (G) and carbon nanotube (CNT). The workability, compressive strength, microstructural characteristics, and alternating current (AC) impedance response are investigated. The effect of electrical percolation on the piezoresistive behaviour is studied and discussed using various ratios of G/CNT. Results indicate that as the G/CNT ratio decreases from 4:0 to 0:4, the compressive strength is reduced from 194.7 MPa to 166.3 MPa due to the certain increase in the plastic viscosity of fresh mixture and the proportion of harmful pores, although the basic requirement of 150 MPa is met. Moreover, the AC impedance response significantly moves left and the radius of high-frequency arc reduces from 72910 Ω to 1295 Ω, suggesting electrical percolation. Bounded by percolation threshold, the fractional change of resistance curves can be divided into a two-stage pattern (i.e., linear and nonlinear stages) and a three-stage mode (i.e., linear decrease, balance, and abrupt increase stages). An underlying mechanism is proposed to explain the tremendous change in piezoresistive behaviour of self-sensing UHPC, considering the tunneling-percolation theory and electromechanical coupling behaviour. Additionally, the gauge factors range from 11 to 28, which is higher than most of the existing reported values, demonstrating the great potential of using hybrid functional nano-additives in self-sensing UHPC.

自传感超高性能混凝土（UHPC）具有卓越的机械能力、出色的抗侵蚀性、较长的使用寿命和广泛的应力传感范围，有望成为实现下一代智能水泥基复合材料的途径。本研究提出了一种新颖的策略，通过加入多相多尺度功能添加剂（包括石墨烯（G）和碳纳米管（CNT）），实现 UHPC 的电渗流并提高其压阻传感能力。研究了该材料的可加工性、抗压强度、微观结构特征和交流阻抗响应。使用不同比例的 G/CNT 研究和讨论了电渗对压阻行为的影响。结果表明，随着 G/CNT 的比例从 4:0 降低到 0:4，由于新鲜混合物的塑性粘度和有害孔隙比例有一定程度的增加，抗压强度从 194.7 兆帕降低到 166.3 兆帕，但仍能满足 150 兆帕的基本要求。此外，交流阻抗响应明显左移，高频电弧半径从 72910 Ω 减小到 1295 Ω，表明存在电渗。以渗滤阈值为界，电阻分数变化曲线可分为两阶段模式（即线性和非线性阶段）和三阶段模式（即线性下降、平衡和突然上升阶段）。考虑到隧道珀尔塞理论和机电耦合行为，提出了一种基本机制来解释自感应 UHPC 压阻行为的巨大变化。此外，量规因子从 11 到 28 不等，高于大多数现有报告值，这表明在自感应超高分子量聚碳酸酯中使用混合功能纳米添加剂具有巨大潜力。

Composites Science and Technology

Nanofibrillar self-reinforced cyclic olefin copolymer composite foam with high toughness and thermal insulation

Kim Eric S., Lu Miao, Zhang Ruiyan, Lee Patrick C.

doi:10.1016/j.compscitech.2023.110306

具有高韧性和隔热性能的纳米纤维自增强环烯烃共聚物复合泡沫塑料

Thermally insulating and sustainable polyolefin foams play an important role in alleviating heat waste. Cyclic olefin copolymer (COC) has remarkable heat resistance and low thermal conductivity, which makes it an excellent candidate as a thermal insulative material. However, COC has critical drawbacks in its foam processing due to low melt strength, which limits its effective application as a thermal insulative material. Herein, we exploit nanofibrillar processing technology to enhance melt strength to develop highly tough and thermally insulating self-reinforced COC composites. The nanofibril network generated by drawing from the COC blends provides dramatic enhancements in the mechanical, rheological and final foam and thermal insulation properties. In particular, this process increases tensile toughness of COC composites by up to twenty-folds higher than neat COC. The results of foam process reveal the presence of COC fibrils in COC matrix improved volume expansion ratio as well as the cell density of the COC composites. Specifically, the expansion ratio of the foams reaches up to 11 with a cell density of 107 cell/cm3, two orders of magnitude higher than that of neat COC foams and thermal conductivity decreased from 0.062 to 0.033 W m−1K−1. As a proof of concept, this work provides a new insight of a self-reinforced approach to develop recyclable, highly tough, and thermally insulative foam.

隔热和可持续的聚烯烃泡沫在减少热浪费方面发挥着重要作用。环状烯烃共聚物（COC）具有显著的耐热性和低导热性，是绝热材料的理想候选材料。然而，环烯烃共聚物由于熔体强度低，在泡沫加工过程中存在严重缺陷，限制了其作为隔热材料的有效应用。在此，我们利用纳米纤维加工技术来提高熔体强度，从而开发出高韧性、高隔热性的自增强 COC 复合材料。从 COC 混合物中抽丝生成的纳米纤维网可显著提高机械、流变、最终泡沫和隔热性能。特别是，与纯 COC 相比，该工艺可将 COC 复合材料的拉伸韧性提高 20 倍。泡沫工艺的结果表明，COC 基质中 COC 纤维的存在提高了 COC 复合材料的体积膨胀率和细胞密度。具体来说，泡沫的膨胀率高达 11，细胞密度为 107 cells/cm3，比纯 COC 泡沫高两个数量级，导热系数从 0.062 W m-1K-1 降至 0.033 W m-1K-1。作为概念验证，这项研究为开发可回收、高韧性和隔热泡沫的自增强方法提供了新的视角。

The fibre kinking fracture toughness of laminated composites under combined compression and shear

He Rui, Cheng Longfei, Gao Yidi, Cui Hao, Li Yulong

doi:10.1016/j.compscitech.2023.110307

层压复合材料在压缩和剪切联合作用下的纤维扭结断裂韧性

Compact compression specimens with off-axis fibres are employed in this paper, to investigate the effect of in-plane shear stress on the fibre kinking compressive fracture toughness of laminates. The strain distribution on the surface of the specimen was analysed using the digital image correlation method, and the damage process was monitored with thermal imaging. It was noted that the in-plane shear stress introduced by off-axis angle fibres caused an increase in the values of the R-curves when the off-axis angle was 10° or more. The microscopic morphology reveals that as the off-axis angle of the fibres increases, there is an increasing splitting of large fibre bundles, followed by the fibre compression failure within these bundles. This multi-step damage process may be responsible for the increase in energy dissipation.

本文采用了带有离轴纤维的紧凑压缩试样，以研究面内剪应力对层压板纤维扭结压缩断裂韧性的影响。采用数字图像相关方法分析了试样表面的应变分布，并利用热成像技术监测了破坏过程。结果表明，当偏离轴角为 10° 或更大时，偏离轴角纤维引入的面内剪应力会导致 R 曲线值增加。微观形态显示，随着纤维偏离轴心的角度增大，大纤维束的劈裂越来越多，随后这些纤维束内的纤维压缩失效。这种多步骤破坏过程可能是能量耗散增加的原因。

来源：复合材料力学仿真Composites FEM

【新文速递】2023年10月17日固体力学SCI期刊最新文章

今日更新：Journal of the Mechanics and Physics of Solids 2 篇，Mechanics of Materials 1 篇Journal of the Mechanics and Physics of SolidsA unified strength criterion for two-dimensional materials via bond failure analysisZhang Guoqiang, Chen Yan, Yue Shengying, Zhang Yong-Wei, Qin Huasong, Liu Yilundoi:10.1016/j.jmps.2023.105466通过粘接破坏分析得出二维材料的统一强度标准The family of two-dimensional (2D) materials, including graphene, hexagonal boron nitride, transition metal dichalcogenides, and others, exhibits a wide range of lattice structures and defect configurations, leading to complex deformation mechanisms and mechanical failure behaviors. However, there is currently no universally accepted criterion that accurately describes the mechanical failures of these materials. In this study, we aim to address this issue by introducing the concept of intrinsic bond strength, which is solely dependent on the local chemical environment of the bond and is independent of loading states, defect types, and fracture bonds. We demonstrate the existence of this intrinsic bond strength and propose a unified strength criterion that considers the balance between the intrinsic bond strength and local stress state for any 2D material. By employing this unified strength criterion, we are able to accurately predict the failure of various 2D materials with different types of defects, including voids, cracks, grain boundaries, and hydrogenation. This work resolves a long-standing issue in predicting the mechanical failure of 2D materials via bond failure analysis, and carries important implications for the design and development of 2D materials with enhanced mechanical properties.二维（2D）材料家族，包括石墨烯、六方氮化硼、过渡金属二卤化物等，呈现出多种多样的晶格结构和缺陷构型，导致复杂的变形机制和机械失效行为。然而，目前还没有一个普遍接受的标准来准确描述这些材料的机械失效。在本研究中，我们旨在通过引入本征键强度的概念来解决这一问题，本征键强度完全取决于键的局部化学环境，与加载状态、缺陷类型和断裂键无关。我们证明了本征结合强度的存在，并提出了一种统一的强度准则，该准则考虑了任何二维材料的本征结合强度和局部应力状态之间的平衡。通过采用这一统一强度准则，我们能够准确预测具有不同类型缺陷（包括空隙、裂纹、晶界和氢化）的各种二维材料的失效。这项工作解决了长期以来通过键合失效分析预测二维材料力学失效的问题，对设计和开发具有更强力学性能的二维材料具有重要意义。What are the “dispersive shear bands” on the surfaces of layered heterostructured materials?Ma Huwen, Zhao Yanchun, Lyu Zhi, Wang Xue, Zhu Yuntian, Gao Yanfeidoi:10.1016/j.jmps.2023.105467 什么是层状异质结构材料表面的 "分散剪切带"？Hetero-deformation-induced (HDI) strengthening mechanism has been well investigated in heterostructured materials including layered/gradient materials prepared by surface attrition or other processing techniques. While the roles played by the geometrically necessary dislocations (GNDs) and the forward/back stresses on the grain scale have been a focus in nearly all these studies, some latest works reveal the peculiar formation of “dispersive shear bands” or strain localizations on the surfaces of layered/gradient materials. Feature sizes of these “shear bands” are commensurate with the macroscopic sample size, but not on the microstructural length scales, thus excluding the HDI strengthening as the primary mechanism. In this work, using a sandwich structure as an illustrative example, we demonstrate that the origin of these shear bands be localized necking with intermediate wavelengths and inclined orientations, which are critically dictated by the hardening behavior of the constituent layers, the geometric parameters, and the initial morphological perturbations. The layered structure under tension may not neck with an infinite wavelength (i.e., the Considère mode), but neck at intermediate wavelengths which actually correspond to a much larger uniform ductility than the commonly observed Considère necking mode. The arrangements of these shear bands can be further classified as I, X, and W types. Findings in this work not only resolve the origin of recent unusual experimental observations, but also suggest an alternative way of understanding and improving the ductility in heterostructured materials.异质形变诱导（HDI）强化机制已在异质结构材料中得到深入研究，包括通过表面损耗或其他加工技术制备的层状/梯度材料。几乎所有这些研究都重点关注了几何必要位错（GNDs）和晶粒尺度上的前向/后向应力所发挥的作用，而一些最新研究则揭示了层状/梯度材料表面 "分散剪切带 "或应变定位的奇特形成。这些 "剪切带 "的特征尺寸与宏观样品尺寸相称，但与微观结构长度尺度不符，因此排除了高密度互联强化作为主要机制的可能性。在这项工作中，我们以三明治结构为例，证明了这些剪切带的起源是具有中间波长和倾斜方向的局部颈缩，这主要由组成层的硬化行为、几何参数和初始形态扰动决定。张力作用下的层状结构可能不会以无穷大的波长（即康西代尔模式）出现缩颈，而是以中间波长出现缩颈，这实际上对应于比通常观察到的康西代尔缩颈模式大得多的均匀延展性。这些剪切带的排列可进一步分为 I、X 和 W 三种类型。这项工作的发现不仅解决了近期不寻常实验观测的起源问题，还为理解和改进异质结构材料的延展性提出了另一种方法。Mechanics of Materials4D local investigation of mechanical behavior of open-cell foams by enhanced morphological analysis and microstructure-adapted digital volume correlation for tribology applicationsLacaj E., Doumalin P., Bouyer J., Jolly P., Henry Y., Fatu A., Beaudoin A., Ennazii A.-E., Couderc B., King A.doi:10.1016/j.mechmat.2023.104836通过增强形态分析和微结构适配数字体积相关性对开孔泡沫的机械行为进行四维局部研究，以促进摩擦学应用In ex-poro-hydrodynamic (XPHD) lubrication, fluid impregnated, open-cell elastomer foams constitute a composite material aiming to improve the load carrying and damping capacity of lubricated systems and to provide more environmentally sustainable solutions. The performance of XPHD-based devices depends on the interactions between solid and fluid phases, occurring and evolving simultaneously during dynamic compression of an imbibed foam. Even at normal regimes, the foam microstructure undergoes large deformations and is prone to strain concentrations which modify its local porosity and influence the mechanical behavior of the composite. In this context, this work focuses on the development of a systematic and accurate characterization technique for describing the main morphological changes happening under uniaxial compression of a high porosity dry open-cell polyurethane foam, by in-situ X-ray microtomography (μCT) testing. A combination of 3D image analysis and digital volume correlation (DVC) is considered to identify and trace the spatial and temporal location of key microstructural features at every loaded state. In this way, the detailed transformations of cells and pores obtained by this method are presented here to give further insight into the deformation mechanisms involved. Then, the advantages and the limits of the overall methodology in analyzing high porosity open-cell foams are regarded in terms of feature segmentation and measurement precision. Both a classic and a microstructure-adapted DVC are compared at their respective scales, and finally their sensibility to emphasize local strain heterogeneities is discussed.在孔外流体动力（XPHD）润滑中，流体浸渍开孔弹性泡沫构成了一种复合材料，旨在提高润滑系统的承载能力和阻尼能力，并提供更具环境可持续性的解决方案。基于 XPHD 的设备的性能取决于固相和流体相之间的相互作用，这种相互作用在浸泡泡沫的动态压缩过程中同时发生和发展。即使在正常状态下，泡沫微观结构也会发生较大变形，并容易产生应变集中，从而改变局部孔隙率，影响复合材料的机械行为。在这种情况下，这项工作的重点是开发一种系统而精确的表征技术，通过原位 X 射线显微层析（μCT）测试，描述高孔隙率干法开孔聚氨酯泡沫在单轴压缩下发生的主要形态变化。三维图像分析和数字体积相关（DVC）相结合，可识别和追踪每个加载状态下关键微观结构特征的空间和时间位置。因此，本文介绍了该方法获得的细胞和孔隙的详细变化，以便进一步了解相关的变形机制。然后，从特征分割和测量精度的角度，探讨了分析高孔隙率开孔泡沫的整体方法的优势和局限性。比较了经典 DVC 和微结构适应 DVC 各自的尺度，最后讨论了它们对强调局部应变异质性的敏感性。来源：复合材料力学仿真Composites FEM