【新文速递】2024年4月5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 1 篇，Composites Part B: Engineering 1 篇，Composites Science and Technology 1 篇

Composite Structures

A novel ductile connection for FRP pultruded beam-to-column assemblies

Francesco Ascione, Mario D'Aniello, Luciano Feo, Luigi Granata, Raffaele Landolfo

doi:10.1016/j.compstruct.2024.118091

玻璃钢拉挤梁柱组件的新型延性连接方式

The resistance, stiffness and ductility of the joints between Fibre Reinforced Polymer (FRP) members play a key role in ensuring the required structural performance of pultruded composite frames. Both bonded and bolted joints are characterised by poor mechanical performance due to brittle failure and low resistance respectively. Hybrid joints are stronger and more ductile, but are still affected by some criticisms such as (i) non-repairability, (ii) the presence of holes in the fibre-reinforced material, (iii) the difficulty of assembling a transverse beam into the joint, which is typically required for real 3D systems. To overcome such limitations, a novel ductile connection has been developed by combining ductile steel elements bonded to FRP members. The steel elements are bolted together and are designed to be weaker than the FRP profiles and adhesive. Experimental tests on beam-column assemblies have been carried out and the test results have shown that the investigated hybrid connection is characterised by adequate stiffness, resistance and high ductility. The damage is concentrated in the bolted steel elements, which can be easily replaced, confirming the repairability of the assembly.

纤维增强聚合物（FRP）构件之间接头的阻力、刚度和延展性对于确保拉挤复合材料框架所需的结构性能起着关键作用。粘合连接和螺栓连接的机械性能都很差，原因分别是脆性破坏和低阻力。混合连接强度更高、延展性更好，但仍受到一些批评，如：(i) 不可修复性，(ii) 纤维增强材料中存在孔洞，(iii) 难以将横梁装配到连接中，而这正是真正的三维系统通常需要的。为了克服这些限制，我们开发了一种新型延性连接，将延性钢构件与玻璃纤维增强材料构件结合在一起。钢构件通过螺栓连接在一起，设计强度低于玻璃钢型材和粘合剂。对梁柱组件进行了实验测试，测试结果表明，所研究的混合连接具有足够的刚度、阻力和高延展性。损坏主要集中在螺栓连接的钢构件上，这些构件可以很容易地进行更换，从而证实了该组件的可修复性。

Composites Part A: Applied Science and Manufacturing

Lightweight multifunctional electromagnetic shielding composites achieved by depositing Ag@MXene hybrid particles on wood-based aerogel

Shuang Wu, Ting-yu Zhu, Zhu Zeng, De-xiang Sun, Jing-hui Yang, Xiao-dong Qi, Yong Wang

doi:10.1016/j.compositesa.2024.108193

通过在木质气凝胶上沉积 Ag@MXene 混合颗粒实现轻质多功能电磁屏蔽复合材料

As electronic devices become more integrated into daily life, concerns about electromagnetic radiation pollution become more severe, despite the increased portability they offer. Designing a lightweight and multifunctional material that is environmentally friendly, thermally conductive, and electromagnetically shielded is urgently needed. In this work, novel composites were fabricated by incorporating Ag@MXene hybrid particles into the wood-based aerogel. Compared with the aerogels containing only Ag nanoparticles (AgNPs) or MXene, the Ag@MXene/W aerogel exhibited more homogeneous dispersion of unfolded MXene nanosheets and more AgNPs but higher porosity (97.1 %) and smaller density (0.047 g cm−3). Consequently, the Ag@MXene/W aerogel exhibited high compressibility and low energy dissipation, remarkable strain sensitivity, impressive electrical conductivity (33.9 S m−1) and specific electromagnetic shielding efficiency (5765.96 dB cm2 g−1), and high thermal conductivity (0.81 W m−1 K−1). The excellent comprehensive performances ensure that the aerogel has wide applications in various fields, including electromagnetic pollution protection, strain detecting, and thermal management, etc.

随着电子设备越来越多地融入日常生活，人们对电磁辐射污染的担忧也越来越严重，尽管这些设备具有更强的便携性。设计一种环保、导热、电磁屏蔽的轻质多功能材料迫在眉睫。在这项研究中，通过在木质气凝胶中加入 Ag@MXene 混合颗粒，制造出了新型复合材料。与仅含银纳米粒子（AgNPs）或MXene的气凝胶相比，Ag@MXene/W气凝胶显示出更均匀的展开MXene纳米片和更多的AgNPs，但孔隙率更高（97.1%），密度更小（0.047 g cm-3）。因此，Ag@MXene/W 气凝胶具有高压缩性和低能量耗散、显著的应变敏感性、出色的导电性（33.9 S m-1）和特定电磁屏蔽效率（5765.96 dB cm2 g-1）以及高导热性（0.81 W m-1 K-1）。出色的综合性能确保了气凝胶在电磁污染防护、应变检测和热管理等多个领域的广泛应用。

Composites Part B: Engineering

A mechanical strong yet ductile CoCrNi/Cr2B composite enabled by in-situ formed borides during laser powder bed fusion

Junhua Hou, Bingnan Qian, Zhiguang Zhu, Sihao Zou, Gan Li, Qiang Zhu, Wenjun Lu

doi:10.1016/j.compositesb.2024.111428

在激光粉末床熔融过程中原位形成的硼化物使 CoCrNi/Cr2B 复合材料具有机械强度和韧性

The design of metal matrix composites predominantly focusses on synergistically integrating the intrinsic properties of matrix and reinforcing phase aiming to achieve outstanding strength and ductility simultaneously. In metal matrix composites, the reinforcing phase invariably faces challenges such as agglomeration and non-uniform distribution, resulting in a significant reduction in mechanical properties. Here, we propose a method to overcome this barrier through an in-situ alloying of laser powder bed fusion i.e., redistributing the reinforcing phase (Cr2B boride) in medium entropy alloy matrix (CoCrNi). The in-situ alloying can be achieved by a mixture of CoCrNi powders and B4C particles. After remelting, a nano-sized core-shell structure is developed by establishing “soft core” of CoCrNi matrix embedded with “hard shell” of Cr2B boride. Such nano-sized core-shell structure mainly contributes to a yield strength (867 ± 1.6 MPa), a high tensile strength (1200 ± 13 MPa) and a decent ductility (17 ± 0.5%) of the CoCrNi/Cr2B composite due to the load bearing strengthening and hetero-deformation induced hardening. Additionally, the crack propagation can be suppressed by the CoCrNi matrix/Cr2B interface. The insights provide a new design strategy of in-situ formation of the nano-sized core-shell structure to develop the metal matrix composites with high strength and ductility.

金属基复合材料的设计主要侧重于将基体和增强相的固有特性进行协同整合，以同时获得出色的强度和延展性。在金属基复合材料中，增强相总是面临团聚和分布不均匀等挑战，导致机械性能显著降低。在此，我们提出了一种克服这一障碍的方法，即通过激光粉末床融合的原位合金化，在中熵合金基体（CoCrNi）中重新分配增强相（硼化 Cr2B）。钴铬镍粉末和 B4C 颗粒的混合物可实现原位合金化。重熔后，通过建立钴铬镍基体的 "软核 "和嵌入硼化铬的 "硬壳"，形成了纳米级的核壳结构。这种纳米级核壳结构主要通过承载强化和异质变形诱导硬化，使 CoCrNi/Cr2B 复合材料具有较高的屈服强度（867 ± 1.6 兆帕）、拉伸强度（1200 ± 13 兆帕）和良好的延展性（17 ± 0.5%）。此外，CoCrNi 基体/Cr2B 界面还能抑制裂纹扩展。这些见解为原位形成纳米级核壳结构以开发具有高强度和延展性的金属基复合材料提供了新的设计策略。

Composites Science and Technology

Enhancing structural battery performance: Investigating the role of conductive carbon additives in LiFePO4-Impregnated carbon fiber electrodes

Yasemin Duygu Yücel, Erik Adolfsson, Henrik Dykhoff, Jocke Pettersson, Stacy Trey, Maciej Wysocki, Erika Widenkvist Zetterström, Dan Zenkert, Rakel Wreland Lindström, Goran Lindbergh

doi:10.1016/j.compscitech.2024.110571

提高结构电池性能：研究导电碳添加剂在磷酸铁锂浸渍碳纤维电极中的作用

This study centers on investigating the influence of conductive additives, carbon black (Super P) and graphene, within the context of LiFePO4 (LFP)-impregnated carbon fibers (CFs) produced using the powder impregnation method. The performance of these additives was subject to an electrochemical evaluation. The findings reveal that there are no substantial disparities between the two additives at lower cycling rates, highlighting their adaptability in conventional energy storage scenarios. However, as cycling rates increase, graphene emerges as the better performer. At a rate of 1.5C in a half-cell versus lithium, electrodes containing graphene exhibited a discharge capacity of 83 mAh g LFP − 1 ; those with Super P and without any additional conductive additive showed a capacity of 65 mAh g LFP − 1 and 48 mAh g LFP − 1 , respectively. This distinction is attributed to the structural and conductivity advantages inherent to graphene, showing its potential to enhance the electrochemical performance of structural batteries. Furthermore, LFP-impregnated CFs were evaluated in full cells versus pristine CFs, yielding relatively similar results, though with a slightly improved outcome observed with the graphene additive. These results provide valuable insights into the role of conductive additives in structural batteries and their responsiveness to varying operational conditions, underlining the potential for versatile energy storage solutions.

本研究主要探讨导电添加剂炭黑（Super P）和石墨烯对采用粉末浸渍法生产的磷酸铁锂（LFP）浸渍碳纤维（CF）的影响。对这些添加剂的性能进行了电化学评估。研究结果表明，在较低的循环速率下，两种添加剂之间没有实质性差异，这突出表明了它们在传统储能方案中的适应性。然而，随着循环速率的增加，石墨烯的性能更优。在半电池与锂电池的 1.5C 循环速率下，含有石墨烯的电极显示出 83 mAh g LFP - 1 的放电容量；含有超级 P 和不含任何额外导电添加剂的电极分别显示出 65 mAh g LFP - 1 和 48 mAh g LFP - 1 的容量。这种区别归因于石墨烯固有的结构和导电性优势，显示出其增强结构电池电化学性能的潜力。此外，在完整电池中对浸渍了 LFP 的 CF 与原始 CF 进行了评估，结果相对相似，但石墨烯添加剂的结果略有改善。这些结果为了解导电添加剂在结构电池中的作用及其对不同操作条件的响应提供了宝贵的见解，凸显了多功能储能解决方案的潜力。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年3月16日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇International Journal of Solids and StructuresAnomalous buckling of odd elastic platesAndi Lai, Guo Fu, C.W. Limdoi:10.1016/j.ijsolstr.2024.112774 奇数弹性板的反常屈曲Buckling of thin-walled structures such as plates and shells is a consequence of in-plane stress being released through out-of-plane displacements. Generally, thin-walled structures that are subjected to tension or zero stress conditions remain stable. In this article, the anomalous tension buckling and stress-free active buckling of odd elastic plates are reported, which are a novel instability caused by odd elastic effects. The latter can only occur in the form of left- or right-handed chiral deformation and it does not involve external loads or internal active stress in a critical state. We demonstrate that the chiral rotation angle deformation is responsible for the active buckling of the plates, because the energy required for instability can be obtained based on the odd elastic effect. These findings can serve as an interpretation in a novel way for the occurrence of surface morphologies with biological activities, as well as provide references for buckling designs and applications of active structures.板和壳等薄壁结构的屈曲是平面内应力通过平面外位移释放的结果。一般来说，薄壁结构在拉伸或零应力条件下会保持稳定。本文报告了奇异弹性板的反常拉伸屈曲和无应力主动屈曲，这是一种由奇异弹性效应引起的新型不稳定性。后者只能以左旋或右旋手性变形的形式发生，在临界状态下不涉及外部载荷或内部主动应力。我们证明，手性旋转角变形是板块主动屈曲的原因，因为不稳定所需的能量可以根据奇异弹性效应获得。这些发现以一种新颖的方式解释了具有生物活性的表面形态的发生，并为活性结构的屈曲设计和应用提供了参考。Mechanics of MaterialsA novel metamaterial with instantaneously sign-switchable coefficient of thermal expansion and Poisson's ratioHao Wu, Minghui Fu, Mingming Chen, Wen Jiang, Rongchang Zhong, Binbin Zheng, Jingxiang Huangdoi:10.1016/j.mechmat.2024.104974热膨胀系数和泊松比可瞬时符号切换的新型超材料Most materials expand when heated and contract when cooled. In contrast, negative thermal expansion materials exhibit the opposite behavior. In this paper, we present a metamaterial that expands both when heated and cooled. The unit cell configuration is crafted by embedding two isosceles triangular structures composed of high thermal expansion materials within a re-entrant hexagonal honeycomb framework. Initially, the bases of the two isosceles triangles are in contact. The metamaterial exhibits two deformation states under different external loads. Analytical formulas for the equivalent parameters were derived based on classical beam theory within the regime of small deformation. Finite element simulations were conducted to validate the accuracy of these analytical formulas. The influence of geometric parameters on the metamaterial is discussed in detail. The results demonstrate that the metamaterial can exhibit excellent multi-functional properties within a small range of deformation, including instantaneous sign-variable coefficients of thermal expansion and Poisson's ratios, along with significantly distinct tensile and compressive stiffnesses. This metamaterial consistently exhibits expansive characteristics regardless of variations in ambient temperature. Additionally, the material always expands laterally regardless of the sign of uniaxial loads. Based on these properties, the metamaterial can be applied to fasteners in the aerospace industry that require permanent locking, ensuring stability in various temperature and mechanical load conditions.大多数材料在加热时膨胀，冷却时收缩。相反，负热膨胀材料则表现出相反的行为。在本文中，我们介绍了一种在加热和冷却时都会膨胀的超材料。我们将两个由高热膨胀材料组成的等腰三角形结构嵌入一个再入六边形蜂窝框架中，从而制作出这种单元格结构。起初，两个等腰三角形的底面相接触。超材料在不同的外部载荷作用下呈现出两种变形状态。在小变形状态下，根据经典梁理论推导出了等效参数的分析公式。为了验证这些分析公式的准确性，还进行了有限元模拟。详细讨论了几何参数对超材料的影响。结果表明，该超材料可在小变形范围内表现出卓越的多功能特性，包括瞬时符号可变的热膨胀系数和泊松比，以及明显不同的拉伸和压缩刚度。无论环境温度如何变化，这种超材料始终表现出膨胀特性。此外，无论单轴载荷的符号如何，该材料始终具有横向膨胀性。基于这些特性，这种超材料可应用于航空航天工业中需要永久锁定的紧固件，确保在各种温度和机械负载条件下的稳定性。International Journal of PlasticityAnalysis of slip transfer across grain boundaries in Ti via diffraction contrast tomography and high-resolution digital image correlation: When the geometrical criteria are not sufficientE. Nieto-Valeiras, A. Orozco-Caballero, M. Sarebanzadeh, J. Sun, J. LLorcadoi:10.1016/j.ijplas.2024.103941通过衍射对比断层扫描和高分辨率数字图像相关性分析钛中晶界的滑移转移：当几何标准不充分时High-resolution digital image correlation was employed to analyze the occurrence of slip transfer across grain boundaries in pure Ti. The microstructure was characterized in 3D through diffraction contrast tomography and electron backscatter diffraction. The prismatic slip activity was captured in the shear strain maps at different strains, and the grain boundaries were classified according to the occurrence/absence of slip transfer. Different geometrical slip transfer criteria were tested, and, in general, the slip transfer likelihood increased when the slip systems across the boundary were well-aligned. Nevertheless, a detailed analysis of selected grain boundaries revealed that slip transfer could be triggered or impeded depending on the local stresses acting on the neighborhood, regardless of the alignment between the slip systems. The microstructural and deformation patterns where the geometrical criteria are not enough to predict slip transfer are assessed.采用高分辨率数字图像相关技术分析了纯钛中发生的晶界滑移。通过衍射对比断层扫描和电子反向散射衍射对微观结构进行了三维表征。不同应变下的剪切应变图捕捉到了棱柱滑移活动，并根据滑移发生/不发生对晶界进行了分类。对不同的几何滑移标准进行了测试，一般来说，当边界上的滑移系统排列整齐时，滑移的可能性会增加。然而，对所选晶粒边界的详细分析显示，滑移转移的触发或阻碍取决于作用于邻域的局部应力，而与滑移系统之间的排列无关。在几何标准不足以预测滑移的情况下，我们对微观结构和变形模式进行了评估。来源：复合材料力学仿真Composites FEM