今日更新：Composite Structures 2 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Part B: Engineering 2 篇，Composites Science and Technology 2 篇Composite StructuresComprehensive investigation into grinding characteristics and damage behavior of Cf/SiC composite modified by picosecond-laser ablatingXiao Guijian, Li Xin, Zhou Kun, Yang Zhengyudoi:10.1016/j.compstruct.2023.117600皮秒激光烧蚀改性 Cf/SiC 复合材料的磨削特性和损伤行为综合研究Cf/SiC composite is known as difficult-to-machine materials. This study introduced laser-ablating assisted grinding (LAAG) method, and explored the relationship between processing parameters and surface/subsurface damage behavior of Cf/SiC composite. It was revealed that SiO2 ablation products with a loose structure were formed during picosecond-laser ablating, and the ablated layers showed excellent machinability during grinding. Cf/SiC composite underwent brittle removal during conventional grinding (CG); however, significant ductile fracture and smeared removal appearance were clearly observed on the ground surfaces during LAAG. As the grinding speed increased, the grinding forces during LAAG were further decreased, and the brittle-ductile transformation of the normal fiber became more significant. The increase of feed speed would increase the grinding forces and enhance the brittle removal behavior of Cf/SiC composite. The laser power affected the machined quality through the ablation depth and the ablative transformation, and a smaller laser scanning distance would result in a flatter ground surface. Furthermore, subsurface damage of Cf/SiC composite after LAAG was slight, which primarily displayed as interface debonding and SiC matrix cracking. The grinding chips generated during LAAG were primarily composed of cut fiber-bundle and curled SiC matrix, rather than macro-fractured fiber and matrix with unordered size and shape.Cf/SiC 复合材料是众所周知的难加工材料。本研究引入激光烧蚀辅助研磨（LAAG）方法，探讨了 Cf/SiC 复合材料的加工参数与表面/次表面损伤行为之间的关系。结果表明，在皮秒激光烧蚀过程中形成了结构疏松的二氧化硅烧蚀产物，烧蚀层在研磨过程中表现出良好的可加工性。Cf/SiC复合材料在传统磨削（CG）过程中会发生脆性去除；但在LAAG过程中，磨削表面明显出现韧性断裂和斑点状去除。随着磨削速度的增加，LAAG 磨削过程中的磨削力进一步减小，普通纤维的脆-韧性转变更加明显。进给速度的增加会提高磨削力，并增强 Cf/SiC 复合材料的脆性去除行为。激光功率通过烧蚀深度和烧蚀转变影响加工质量，激光扫描距离越小，磨削表面越平整。此外，LAAG 后 Cf/SiC 复合材料的次表面损伤轻微，主要表现为界面脱粘和 SiC 基体开裂。LAAG 过程中产生的磨屑主要由切割的纤维束和卷曲的碳化硅基体组成，而不是尺寸和形状无序的宏观断裂纤维和基体。Natural frequencies of submerged microplate structures, coupled to stationary fluid, using modified strain gradient theoryKhorshidi Korosh, Soltannia Babak, Karimi Mahdi, Zakaryaei Mahdidoi:10.1016/j.compstruct.2023.117583利用修正的应变梯度理论计算与静止流体耦合的浸没式微板结构的固有频率This paper investigates the free vibration analysis of a microplate, interacting with a stationary fluid. For the fluid part, the potential flow assumptions are considered, and it is supposed to be incompressible, irrotational and inviscid. Different positions for the fluid relative to the structure are studied: a structure in contact with a fluid with a free surface, a submerged microplate and a floating structure. For the structure, the mechanical properties of the microplate such as density, Young modulus and shear modulus are assumed to be a function of structure thickness. Besides, the modified strain gradient theory on the basis of higher-order plate theory is adopted to capture the size effects of the microplate. Using Bernoulli’s relation and fluid velocity potential function, the fluid pressure affecting the microplate is calculated, and then Hamilton’s principle is employed to derive coupled fluid-solid equations of motion. After validation of the presented formulations, a comprehensive parametric study is conducted to exhibit the response of the system under variations of some parameters such as structure mechanical properties, fluid parameters and size- effect parameters.本文研究了与静止流体相互作用的微孔板的自由振动分析。对于流体部分，考虑了势流假设，并假定其为不可压缩、不旋转和不粘性流体。研究了流体相对于结构的不同位置：与自由表面流体接触的结构、浸没微孔板和浮动结构。对于结构，假定微孔板的力学性能（如密度、杨氏模量和剪切模量）是结构厚度的函数。此外，在高阶板理论的基础上采用修正应变梯度理论来捕捉微板的尺寸效应。利用伯努利关系和流体速度势函数计算影响微板的流体压力，然后利用汉密尔顿原理推导流固耦合运动方程。在对所提出的公式进行验证后，进行了全面的参数研究，以展示系统在一些参数（如结构机械性能、流体参数和尺寸效应参数）变化时的响应。Composites Part A: Applied Science and ManufacturingUnderstanding the static performance of composite helical springs with braided nested structuresChen Ling, Chong Joel, Jiang Qian, Wu Liwei, Tang Youhongdoi:10.1016/j.compositesa.2023.107822 了解具有编织嵌套结构的复合螺旋弹簧的静态性能Application of composite helical springs (CHSs) is constrained by their poor static compression performance. In this study, a novel composite helical spring with a braided nested structure (BNCHS) is proposed. The fiber volume fraction (Vf) of BNCHS with braided angle of 15° and 30° (BNCHS15° and BNCHS30°) only increases by 0.9% and 1.8% respectively comparing with that of unidirectional composite helical spring with Vf of 55% (UCHS55%). The compression experimental results show that the spring constant of BNCHS15° and BNCHS30° can reach 105.4% and 171.4% higher than that of UCHS55% respectively. The internal mechanism of significantly improving compression performance of BNCHS is revealed by using a meso model. Numerical result shows that the mises stress of BNCHS15° and BNCHS30° can be 2.43 and 3.14 times higher than that of UCHS55% respectively. Finally, the resilience and specific spring stiffness of BNCHS and steel are compared, highlighting the obvious advantage of static performance of BNCHS.复合螺旋弹簧（CHS）的应用因其较差的静态压缩性能而受到限制。本研究提出了一种新型编织嵌套结构复合螺旋弹簧（BNCHS）。与 Vf 为 55% 的单向复合螺旋弹簧（UCHS55%）相比，编织角为 15° 和 30° 的 BNCHS（BNCHS15° 和 BNCHS30°）的纤维体积分数（Vf）分别只增加了 0.9% 和 1.8%。压缩实验结果表明，BNCHS15° 和 BNCHS30° 的弹簧常数分别比 UCHS55% 高出 105.4% 和 171.4%。利用中观模型揭示了 BNCHS 压缩性能大幅提高的内部机理。数值结果表明，BNCHS15° 和 BNCHS30° 的米塞斯应力分别是 UCHS55% 的 2.43 倍和 3.14 倍。最后，比较了 BNCHS 和钢的回弹性和特定弹簧刚度，突出了 BNCHS 在静态性能方面的明显优势。Composites Part B: EngineeringSiC/Co composite fibers with enhanced conductivity and magnetic coupling developed for reinforcing and high-efficiency electromagnetic absorbing (EMA) materialsGuan Zhen-Jie, Yang Bo-An, Sun Xue-Yin, Li Yang, Jiang Jian-Tang, Song Bo, Gong Yuan-Xun, Zhen Liangdoi:10.1016/j.compositesb.2023.111010 开发出具有增强导电性和磁耦合性的 SiC/Co 复合纤维，用于增强和高效电磁吸收 (EMA) 材料For the design requirements for structural/functional integrated components, it is urgent to find EMA materials combining high-efficient EMA performances and load bearing capacity. Herein, high-strength SiC fibers are modified by Co nanoparticles to construct SiC/Co composite fibers by the liquid-phase method and subsequent hydrogen-thermal annealing. The conductivity of single SiC/Co fiber can be improved by increasing the diameter and content of Co nanoparticles, which leads to enhanced conduction loss and then dominates the dielectric loss. The cross-linked SiC/Co fibers with high conductivity also contribute to significant eddy current loss. Micromagnetic simulation based on Landau-Lifshitz-Gilbert equation (LLG) quantificationally reveals that reducing Co diameter from 140 nm to 30 nm can enhance the ferromagnetic loss by 17.19 times, and this law also can be confirmed by the effect medium theory. Maximum reflection loss (RL max) can reach −78.0 dB at 11.8 GHz and effective absorbing bandwidth with RL < −10 dB (ERL10) of 6.6 GHz can be observed in these SiC/Co-400 filled specimens with the thickness of only 2.7 mm. These SiC/Co fibers present excellent absorbing performances and display the potential for developing into load-bearing and high-efficiency EMA materials.为满足结构/功能一体化组件的设计要求，迫切需要找到兼具高效 EMA 性能和承载能力的 EMA 材料。本文采用液相法和氢热退火法对高强度碳化硅纤维进行钴纳米颗粒改性，从而构建碳化硅/钴复合纤维。单根 SiC/Co 纤维的导电性可以通过增加 Co 纳米粒子的直径和含量得到改善，从而提高传导损耗，进而主导介电损耗。具有高导电率的交联碳化硅/钴纤维也会造成显著的涡流损耗。基于 Landau-Lifshitz-Gilbert 方程（LLG）的微磁模拟定量地揭示了将 Co 的直径从 140 nm 减小到 30 nm 可使铁磁损耗增加 17.19 倍，这一规律也可通过效应介质理论得到证实。最大反射损耗（RL max）可达到 -78.0 dB，频率为 11.8 GHz，RL < -10 dB 的有效吸收带宽（ERL 10）的有效吸收带宽为 6.6 千兆赫，而这些填充有 SiC/Co-400 的试样厚度仅为 2.7 毫米。这些 SiC/Co 纤维具有出色的吸收性能，有望发展成为承重和高效的 EMA 材料。Modelling the gradual through thickness porosity formation and swelling during the thermal aggression of thermoplastic based laminatesPhilippe D., Vieille B., Barbe F.doi:10.1016/j.compositesb.2023.111026基于热塑性塑料的层压板在热侵蚀过程中逐渐通过厚度形成孔隙和膨胀的建模Impacting thermoplastic-based laminates by a high thermal energy -e.g. a flame- essentially causes the progressive deterioration of the matrix, involving solid-state transformations and dramatic variations of the thermomechanical properties. Throughout this process and because it is associated with significant through thickness gradients, the laminates retains a substantial capacity to sustain a mechanical load, even after matrix has melted. For temperatures higher than the melting temperature, the dominant mechanism of the matrix thermal decomposition is the formation of voids. Whereas they constitute a weakness from the mechanical point of view, they act as thermal insulators and contribute to the protection of the matrix on the side opposite to thermal aggression. Thus, describing accurately the kinetics of their formation is the key to a reliable control of the laminates thermomechanical properties evolution under fire conditions. As a prerequisite to this objective, the formation process was experimentally investigated. Results have evidenced the strong dependence of the porosity content and of the related swelling phenomenon to the time and temperature of thermal exposure. A mesoscopic Finite Element model representing porosities at a structural level was developed based on these observations. The porosity nucleation and the induced swelling were reproduced using a probabilistic approach to drive the progressive transformation of elements into porosities according to their thermal state.以热塑性塑料为基础的层压板受到高热能（如火焰）的冲击，基本上会导致基体逐渐退化，其中包括固态转化和热机械性能的剧烈变化。在整个过程中，由于存在明显的厚度梯度，即使在基体熔化后，层压板仍能保持较强的承受机械负荷的能力。当温度高于熔化温度时，基体热分解的主要机制是形成空隙。虽然从机械角度来看，空隙是一个弱点，但它们却能起到热绝缘体的作用，有助于保护与热侵蚀相反一侧的基体。因此，准确描述空隙的形成动力学是可靠控制层压板在火灾条件下的热机械性能演变的关键。作为实现这一目标的先决条件，我们对形成过程进行了实验研究。结果表明，孔隙率和相关的膨胀现象与热暴露的时间和温度密切相关。基于这些观察结果，我们开发了一个介观有限元模型，在结构层面上表示多孔性。利用概率方法再现了多孔成核和诱导膨胀现象，从而根据元素的热状态将其逐步转化为多孔。Composites Science and TechnologyBioinspired polysiloxane/WS2 composites with stretchable and near-infrared light remote-controlled self-healing abilities for deployable deformation actuatorsChen Juxiang, Zhang Kuiyuan, Shi Xiangrong, Huang Yudong, Jiang Bodoi:10.1016/j.compscitech.2023.110297 生物启发聚硅氧烷/WS2 复合材料具有可拉伸和近红外光遥控自愈合能力，可用于可部署形变致动器Despite tremendous advancement of actuators based on self-healing polymeric composites, inevitable trade-offs in maintaining sensitive stimuli response and mechanical and self-healing properties are still left in suspense. Inspired by the character of butterfly wings, herein, we proposed a brand-new strategy to design polysiloxane composites with bioinspired network structure, which consists of tannic acid modified photothermal reagent tungsten disulfide nanosheets as vein and self-healing polysiloxane elastomers with multiple dynamic bonds as embedded membrane. High dense hydrogen bonds between nanosheets and elastomers enable interfaces to enhance interfacial strength of composite. The elaborate bioinspired network was employed as an essential role to endow composites with conspicuous stretchability (1146%), and near-infrared light (NIR) remote-controlled self-healing efficiency (97%). Moreover, the composite with conspicuous bioinspired network structure is connected with low coefficient of thermal expansion film by hydrogen bonds gathered around the interface, which endows deployable deformation actuator with a remarkably fast NIR response (7.50 s) due to bioinspired heat conduction network pathway. This work offers a versatile bioinspired strategy for design of self-healing actuators with conspicuous responding deformation and mechanical properties that enables an application to a wide range of flexible and smart devices.尽管基于自愈合聚合物复合材料的致动器取得了巨大进步，但在保持灵敏的刺 激响应、机械性能和自愈合性能方面仍存在不可避免的权衡问题。受蝴蝶翅膀特性的启发，我们在本文中提出了一种设计具有生物启发网络结构的聚硅氧烷复合材料的全新策略，即以单宁酸修饰的光热试剂二硫化钨纳米片为脉络，以具有多重动态键的自愈合聚硅氧烷弹性体为嵌入膜。纳米片和弹性体之间的高密度氢键使界面成为可能，从而增强了复合材料的界面强度。精心设计的生物启发网络在赋予复合材料明显的拉伸性（1146%）和近红外线（NIR）遥控自愈合效率（97%）方面发挥了重要作用。此外，这种具有明显生物启发网络结构的复合材料通过界面周围聚集的氢键与低热膨胀系数薄膜相连，由于生物启发热传导网络途径，这种复合材料赋予了可部署形变致动器显著的快速近红外响应（7.50 秒）。这项工作为设计具有明显响应形变和机械特性的自愈合致动器提供了一种多功能生物启发策略，可广泛应用于柔性和智能设备。Correlating microstructure-property relationships in carbon fiber-expanded graphite hybrid composites for synergistic improvements in thermal and mechanical propertiesKadiyala Ajay, Owoeye Samuel, Hana John, Krishnamurthy Ajay, Venkatesan Karthik Rajan, Zekriardehani Shahab, Mapkar Javed A., Lawrence Josephdoi:10.1016/j.compscitech.2023.110293 关联碳纤维-膨胀石墨混合复合材料的微观结构-性能关系，协同改善热性能和机械性能Thermally conductive and structurally reinforcing polymer composites are in high demand for applications such as electric vehicles, rapid prototyping, and thermal interface materials. Including a single geometry (platelet or rod) filler is a common strategy to improve the performance of polymers. However, the thermal and mechanical properties follow an inverse dependence and often require high filler loadings that compromise the overall properties. Hybridization of filler geometries has effectively improved the thermal conductive network while retaining mechanical performance. The focus of this work is to understand the effect of microstructure and interactions of hybrid fillers in high strength thermally conductive composites. For this study, expanded graphite, and carbon fibers (CFs) were used as the hybrid filler system to improve the thermal conductivity and mechanical properties of polyamide-based thermoplastic composites. The detailed microstructural study revealed that at a lower normalized weight ratio of CFs, the fibers bridge the expanded graphite particles to create a filler-filler network which leads to synergistic effect on both the tensile strength (by 29%) and thermal conductivity (by 290%) compared to a single-filler expanded graphite-based system. Above a critical mass fraction of CF, the planar graphitic orientation led to a loss in thermal conductivity which is attributed to reduced exfoliation and packing density of fillers.导热和结构增强聚合物复合材料在电动汽车、快速原型制造和热界面材料等应用中需求量很大。采用单一几何形状（板状或棒状）填料是提高聚合物性能的常用策略。然而，热性能和机械性能之间存在反比关系，通常需要较高的填充量，从而影响整体性能。填料几何形状的杂化可有效改善导热网络，同时保持机械性能。这项工作的重点是了解高强度导热复合材料中混合填料的微观结构和相互作用的影响。在这项研究中，膨胀石墨和碳纤维（CFs）被用作混合填料体系，以改善聚酰胺基热塑性复合材料的导热性和机械性能。详细的微观结构研究表明，在较低的碳纤维归一化重量比条件下，碳纤维会与膨胀石墨颗粒架桥，形成填料-填料网络，与基于膨胀石墨的单一填料体系相比，这种网络对拉伸强度（提高 29%）和热导率（提高 290%）都有协同作用。当 CF 的质量分数超过临界质量分数时，平面石墨取向会导致热导率下降，这是由于填料的剥离和堆积密度降低所致。来源：复合材料力学仿真Composites FEM
