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【新文速递】2024年4月9日固体力学SCI期刊最新文章

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今日更新:Mechanics of Materials 1 篇,Thin-Walled Structures 3 篇

Mechanics of Materials

Microstructure characterization and dynamic recrystallization behavior of Ni–Cu alloy during hot deformation

A. Momeni, G.R. Ebrahimi, M. Jahazi, H.R. Ezatpour

doi:10.1016/j.mechmat.2024.105002

Ni-Cu合金热变形过程的显微组织表征及动态再结晶行为

Flow curve and microstructure of Ni–30Cu alloy were studied after hot compression at 1150 °C and strain rate of 0.01 s−1. The stress-strain and work hardening rate curves showed a weak peak at strain of 0.32, followed by a slight dynamic softening. The dominant microstructural mechanisms in low (0.1–0.23) and medium strains (0.23–0.32) were dynamic recovery and dynamic recrystallization, respectively. Microstructural characterizations by electron back scattered diffraction (EBSD) showed that continuous dynamic recrystallization brings about after the peak strain (ε = 0.32) and leads to grain refinement. It was found that the twin boundaries help to activate a grain dissociation mechanism which works as a new variant of continuous dynamic recrystallization. The grain boundary maps developed by EBSD showed that new twin boundaries form through the evolution of low angle grain boundaries. This step, named as “recovery twinning”, was identified as the origin for the observed twinning-assisted continuous dynamic recrystallization (TCDRX). The Kocks-Mecking dislocation evolution model was modified in order to take the dynamic softening by TCDRX into account and describe the variation in the frequency of high angle grain boundaries with strain. Model predictions were validated and confirmed by the experimental results.

研究了Ni-30Cu合金在1150 ℃、应变速率为0.01 s−1的热压缩条件下的流变曲线和显微组织。应力-应变和加工硬化速率曲线在应变为0.32时出现弱峰值,随后出现轻微的动态软化。低应变(0.1 ~ 0.23)和中应变(0.23 ~ 0.32)的主要显微组织机制分别为动态恢复和动态再结晶。电子背散射衍射(EBSD)的显微组织表征表明,在峰值应变(ε = 0.32)之后,晶粒发生了连续的动态再结晶,导致晶粒细化。发现孪晶界有助于激活晶粒解离机制,这是连续动态再结晶的一种新变体。EBSD绘制的晶界图显示,低角度晶界的演化形成了新的孪晶界。这一步骤被称为“恢复孪晶”,被认为是观察到的孪晶辅助连续动态再结晶(TCDRX)的起源。修正了Kocks-Mecking位错演化模型,考虑了TCDRX的动态软化作用,并描述了高角晶界频率随应变的变化规律。实验结果验证了模型预测的正确性。


Thin-Walled Structures

Stacking effects on dynamic mechanical behavior of bilayer hexagonal boron nitride under impact

Xiaodong Qian, Fang Li, Hong Tian

doi:10.1016/j.tws.2024.111866

冲击作用下双层六方氮化硼动态力学行为的叠加效应

Hexagonal boron nitride (h-BN) is a promising material for ballistic armor due to its excellent mechanical properties, enriched by different bilayer stacking arrangements. Molecular dynamics methods are used to study the stacking effects on the static and dynamic mechanical properties of bilayer h-BN. The AB (nitrogen) stacked bilayer structure attracts our attention because of its superior interlayer synergistic ability to resist projectile indentation up to a maximum force of 152.89 nN, which is about 22.9% higher than the average value of other stacked bilayers. The impact response of bilayer h-BN with AB (nitrogen) stacking arrangement is then investigated at velocities of 2-4 km/s, which has the highest critical perforation velocity of 3.075 km/s, increased by 36.7% compared to monolayer h-BN. At a low impact velocity of 2.5km/s, the AB (nitrogen) stacked h-BN bilayer spends the shortest time to dissipate the impact energy of projectile and remains intact, while the top layers of other stacked bilayers are penetrated. At high impact velocities, a perforation event occurs, accompanied by multiple deflections of crack tips from zigzag to armchair to zigzag again, which intrinsically enhances the toughness of material. This study provides more understanding of the dynamic mechanical behavior of bilayer h-BN, as well as the design of armor structures based on stacking arrangements of 2D materials.

六方氮化硼(h-BN)由于其优异的力学性能和不同的双层堆叠方式而成为一种很有前途的弹道装甲材料。采用分子动力学方法研究了叠层效应对双层h-BN静态和动态力学性能的影响。AB(氮)堆叠双层结构因其优异的层间协同抗弹射压痕能力而引起了我们的关注,其抗弹射压痕力最大可达152.89 nN,比其他堆叠双层结构的平均值高出约22.9%。在2 ~ 4 km/s速度下,研究了AB(氮)堆砌双层h-BN的冲击响应,其最高临界射孔速度为3.075 km/s,比单层h-BN提高了36.7%。在2.5km/s的低冲击速度下,AB(氮)堆叠的h-BN双分子层耗散弹丸冲击能的时间最短,且保持完整,而其他堆叠双分子层的顶层被击穿。在高冲击速度下,穿孔事件发生,伴随着裂纹尖端从之字形到扶手形再到之字形的多次偏转,这从本质上提高了材料的韧性。本研究为进一步了解双层h-BN的动态力学行为,以及基于二维材料堆叠排列的装甲结构设计提供了依据。


Nonlinear forced vibration of functionally graded hybrid three-phase nanocomposite toroidal shell segments reinforced by carbon nanotubes (CNTs) and graphene nanoplatelets (GPLs)

Ahmed S. Khalaf, Hamad M Hasan

doi:10.1016/j.tws.2024.111876

碳纳米管和石墨烯纳米片增强功能梯度杂化三相纳米复合材料环形壳段的非线性强迫振动

This study proposes a unique three-phase functionally graded (FG) hybrid nanocomposite material reinforcing the toroidal shell segments to investigate the nonlinear forced vibration using Reddy's higher-order shear deformation theory, von Karman geometrical nonlinearity and Stein-McElman's assumption along with the Hamilton principle. The examined toroidal shell's material consists of polymeric resin, carbon nanotubes (CNTs), and graphene platelets (GPLs) as nanocomposites. The material properties have been derived based on a modified Halpin-Tsai micromechanical model. Four distribution patterns have been studied: uniform (UD), FG-X, FG-O, and FG-V. The continuous distribution of GPLs and CNTs leads to inhomogeneous position-dependent properties throughout the shell thickness. The obtained differential equations of motion have been reduced to ordinary equations using Galerkin's technique. A multi-scales method (MSM) is used to estimate a closed-form solution representing the frequency-amplitude relation, and the state space representation is used along with numerical fourth-order Runge Kutta method (RK4) to obtain the nonlinear dynamic response of the toroidal shell. The accuracy of the current results obtained has been verified by comparing them with the relevant literature and numerical results using (RK4). In addition, the influence of both GPLs and CNTs weight fractions, nanofillers’ distribution types, longitudinal and circumferential wave numbers, elastic foundation parameters, static axial compression load, transverse excitation load, damping ratio, geometrical characteristics of the toroidal shell on the dimensionless natural frequency, nonlinear primary resonance (frequency-amplitude curve), and nonlinear dynamic response are carefully studied. The results found that combining (GPLs & CNTs) into the shell's matrix improves performance, especially in concave shells compared to convex ones. The FG-X pattern reduces peak resonance amplitude and improves natural frequency. A reduction of 12.3% is observed for convex shells, and 21.5% for concave shells compared to FG-O.

利用Reddy的高阶剪切变形理论、von Karman几何非线性、Stein-McElman假设和Hamilton原理,提出了一种独特的三相功能梯度(FG)杂化纳米复合材料增强环面壳段来研究非线性强迫振动。所研究的环形壳体材料由聚合物树脂、碳纳米管(CNTs)和石墨烯片(GPLs)作为纳米复合材料组成。基于改进的Halpin-Tsai微力学模型推导了材料的性能。研究了四种分布模式:均匀分布(UD)、FG-X、FG-O和FG-V。gpl和碳纳米管的连续分布导致了整个壳体厚度的不均匀位置依赖性质。利用伽辽金技术将得到的运动微分方程化为普通方程。采用多尺度法(MSM)估计频率-幅度关系的封闭解,并结合四阶数值龙格库塔法(RK4)进行状态空间表示,得到环面壳的非线性动力响应。通过与相关文献和使用(RK4)的数值结果进行比较,验证了当前所得结果的准确性。此外,还仔细研究了gpl和CNTs重量分数、纳米填料分布类型、纵波数和周向波数、弹性基础参数、静态轴向压缩载荷、横向激励载荷、阻尼比、环形壳几何特性对无量纲固有频率、非线性主共振(频幅曲线)和非线性动力响应的影响。结果发现,与凸壳相比,将(gpl和CNTs)结合到壳的基体中可以提高性能,特别是在凹壳中。FG-X模式降低了峰值共振幅度,提高了固有频率。与FG-O相比,凸壳减少了12.3%,凹壳减少了21.5%。


Cross-section behaviour and capacity of cold-formed austenitic stainless steel flat-oval hollow sections under combined compression and bending

Shuai Li, Ke Jiang, Man-Tai Chen, Andi Su, Tong Guo, Ou Zhao

doi:10.1016/j.tws.2024.111877

冷弯奥氏体不锈钢扁椭圆形空心截面在压缩和弯曲联合作用下的截面行为和性能

Flat-oval hollow section is composed of two semi-circular elements and two flat elements, with the semi-circular elements (exposed to wave and wind) offering a low level of hydrodynamic and aerodynamic drag and the flat elements facilitating connections with other members perpendicular to the wave and wind directions. This paper presents an experimental and numerical study of the cross-section behaviour and resistance of cold-formed austenitic stainless steel flat-oval hollow section stub columns under combined compression and bending. An experimental programme, including initial local geometric imperfection measurements and ten major-axis and minor-axis eccentric compression tests, was firstly carried out, with the test setups, procedures and results fully reported. Following the experimental programme, a numerical modelling programme was performed, with finite element models developed and validated against the eccentric compression test results and then used to conduct parametric studies to generate additional numerical data. Based on the test and numerical results, the relevant codified design interaction curves for cold-formed austenitic stainless steel rectangular hollow sections were evaluated for the applicability to their flat-oval hollow section counterparts. It was found from the evaluation results that the codified design interaction curves led to inaccurate resistance predictions, mainly due to the conservative end points (i.e. cross-section resistances under pure compression and pure bending) and inefficient shapes. Finally, a new design interaction curve was proposed through the use of more accurate end points and more efficient shape and offered more accurate and consistent resistance predictions for cold-formed austenitic stainless steel flat-oval hollow sections under combined loading than the codified design interaction curves.

扁平椭圆形中空截面由两个半圆单元和两个平面单元组成,半圆单元(暴露在波浪和风中)提供低水平的流体动力和空气动力学阻力,平面单元促进与垂直于波浪和风向的其他构件的连接。本文对冷弯奥氏体不锈钢扁椭圆形空心截面短柱在压缩和弯曲联合作用下的截面性能和阻力进行了试验和数值研究。首先进行了一项实验方案,包括初步的局部几何缺陷测量和十次大轴和小轴偏心压缩试验,并全面报告了试验装置、程序和结果。在实验程序之后,进行了数值模拟程序,开发了有限元模型,并根据偏心压缩试验结果进行了验证,然后用于进行参数研究,以生成额外的数值数据。根据试验结果和数值计算结果,评价了冷弯奥氏体不锈钢矩形空心截面的相关规范设计相互作用曲线对扁椭圆形空心截面的适用性。从评价结果中发现,规范的设计交互曲线导致了不准确的阻力预测,主要是由于端点保守(即纯压缩和纯弯曲下的截面阻力)和低效的形状。最后,通过使用更精确的端点和更有效的形状,提出了一种新的设计交互曲线,并提供了比编码设计交互曲线更准确和一致的冷弯奥氏体不锈钢扁椭圆形空心截面在组合载荷下的阻力预测。



来源:复合材料力学仿真Composites FEM
ACTMechanicalDeform振动复合材料非线性电子ADSUG裂纹理论材料分子动力学多尺度试验
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首次发布时间:2024-11-14
最近编辑:12天前
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【新文速递】2024年3月28日复合材料SCI期刊最新文章

今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 7 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 6 篇Composite StructuresDamage evolution of CFRP laminates by normal and oblique impact erosion of pulsating water jetsNaidan Hou, Renxi Zhao, Yifan Yue, Xuan Wang, Hao Cui, Yulong Lidoi:10.1016/j.compstruct.2024.118079脉动水射流正向和斜向冲击侵蚀 CFRP 层压板的损伤演变Impact direction is one of the critical factors affecting the waterdrop erosion behavior of materials. In this paper, rain erosion damage behavior of a typical carbon fiber reinforced polymer (CFRP) laminate is investigated as a function of the impingement angle (0° as normal impact and 15°, 30°, 45° as oblique impact deviated from the normal) and the relative fiber orientation (parallel PA and perpendicular PE to the fiber direction of the surface layer) under the waterjet velocity of 320 m/s and the impact frequency of 50 Hz via a pulsating waterjet erosion test rig. After continuous impact of multiple waterjets, the typical damage of CFRP laminates is mainly composed of the central erosion crater and the upheaval of the surrounding surface layer. The onset and evolution of damage are mainly driven by the shear action of lateral jetting and stress concentration of hydraulic penetration exerted at the surface irregularities. There is no significant difference in the damage modes between the normal and oblique impacts, except for the asymmetric distributions of matrix cracking in PA-orientation and delamination in PE-orientation caused by the angle inclination. With the impingement angle increasing, the volume loss and erosion depth decrease while the incubation period increases mainly due to the decreases of water hammer pressure and contact area. The PA-orientation can cause lower incubation period and larger erosion mass loss than PE-orientation before the surface ply is penetrated, with the underlying mechanism related to the distinct tensile properties of CFRP laminates along longitudinal and transversal directions and the asymmetric properties of fiber–matrix interface. According to the fitting results of erosion curves, it is possible to describe the incubation period and the erosion rate of CFRP laminates under oblique impact using a two-branch equation, and Springer model can give reasonable prediction for the average incubation period and PA-orientation erosion rate of a certain oblique impact occasion with known 0° impact erosion results.冲击方向是影响材料水滴侵蚀行为的关键因素之一。本文通过脉动水射流侵蚀试验台,研究了典型碳纤维增强聚合物(CFRP)层压板在水射流速度为 320 m/s、冲击频率为 50 Hz 条件下的雨水侵蚀破坏行为与冲击角度(0° 为正向冲击,15°、30°、45° 为偏离正向的斜向冲击)和相对纤维取向(平行于表层纤维方向的 PA 和垂直于表层纤维方向的 PE)的函数关系。在多次水射流的连续冲击下,CFRP 层压板的典型损伤主要由中心侵蚀坑和周围表层的动荡组成。损伤的发生和演变主要是由横向喷射的剪切作用和表面不规则处水力渗透的应力集中所驱动的。正向和斜向撞击的损伤模式没有明显差异,只是角度倾斜导致 PA 方向的基体开裂和 PE 方向的分层分布不对称。随着撞击角度的增大,体积损失和侵蚀深度减小,而潜伏期增加,这主要是由于水锤压力和接触面积减小。与 PE 取向相比,PA 取向在表面层被穿透之前会导致更短的潜伏期和更大的侵蚀质量损失,其根本机理与 CFRP 层压板沿纵向和横向的不同拉伸特性以及纤维-基质界面的非对称特性有关。根据侵蚀曲线的拟合结果,可以用一个双支方程来描述 CFRP 层压板在斜面冲击下的潜伏期和侵蚀率,Springer 模型可以在已知 0° 冲击侵蚀结果的基础上,合理预测特定斜面冲击场合的平均潜伏期和 PA 取向侵蚀率。Multiscale analysis of composite pressure vessel structures wound with different fiber tensile forceAleksander Błachut, Jerzy Kaleta, Jerzy Detyna, Barbara Kmiecik, Grażyna Ziętek, Maciej Panek, Mateusz Skoczylasdoi:10.1016/j.compstruct.2024.118065以不同纤维拉力缠绕复合材料压力容器结构的多尺度分析The aim of this paper is the multiscale investigation of composite pressure vessel structures wound with varying fibre tension. The paper explores the potential of ”programming” the fibre tension force during the winding process of a high pressure hydrogen storage vessel. Two series of vessels were wound with two different tensions: Two series of vessels wound with forces of 3 N and 80 N respectively were experimentally investigated. Other technological factors, such as the type and weight of carbon fibre used, were kept constant throughout the study. Quasi-static compression tests were used to measure the elastic deformation of the vessel surface. Microscopic studies were also carried out to analyse the structure of the composite at different length scales. The fibre content, the geometric parameters of the voids and the distribution of the three main components of the composite - carbon fibre, technological defects and resin - were also determined. Representative RVE elementary cells were generated for both materials using statistical modelling. The composite was then homogenised and elasticity matrices were obtained for the fibre tensile forces in both materials.本文旨在对以不同纤维张力缠绕的复合材料压力容器结构进行多尺度研究。本文探讨了在高压储氢容器缠绕过程中对纤维张力进行 "编程 "的可能性。以两种不同的张力缠绕了两个系列的容器:实验研究了缠绕力分别为 3 N 和 80 N 的两个系列容器。在整个研究过程中,使用的碳纤维类型和重量等其他技术因素保持不变。准静态压缩试验用于测量容器表面的弹性变形。此外,还进行了显微研究,以分析复合材料在不同长度尺度上的结构。此外,还确定了纤维含量、空隙的几何参数以及复合材料三种主要成分(碳纤维、技术缺陷和树脂)的分布情况。利用统计建模生成了两种材料的代表性 RVE 基本单元。然后对复合材料进行均匀化处理,并获得两种材料中纤维拉力的弹性矩阵。Dynamic crack growth in orthotropic brittle materials using an adaptive phase-field modeling with variable-node elementsJianan He, Tiantang Yu, Weihua Fang, Sundararajan Natarajandoi:10.1016/j.compstruct.2024.118068利用带有可变节点元素的自适应相场建模在正交脆性材料中实现动态裂纹增长In this paper, crack growth in orthotropic materials subjected to dynamic loading is numerically studied using an adaptive phase-field method. The study starts with a coarse structured mesh and the adaptive refinement strategy based on an user defined threshold on the phase-field variable is proposed for computational efficiency, and variable-node elements are employed to treat the hanging nodes as a result of local adaptive refinement. The Hughes-Hilbert-Taylor (HHT) time integration scheme is adopted for the temporal discretization. The directionality of orthotropic materials is represented by a penalized second-order structural matrix, which is incorporated in the crack face energy density. Through numerical examples, the influence of the material orientation on the dynamic crack growth in orthotropic materials is studied and the reliability of the proposed framework is validated.本文采用自适应相场方法对承受动态载荷的各向同性材料的裂纹生长进行了数值研究。研究从粗结构网格开始,为提高计算效率,提出了基于用户定义的相场变量阈值的自适应细化策略,并采用变节点元素来处理局部自适应细化产生的悬挂节点。时间离散化采用休斯-希尔伯特-泰勒(HHT)时间积分方案。正交各向同性材料的方向性由惩罚性二阶结构矩阵表示,该矩阵被纳入裂纹面能量密度。通过数值实例,研究了材料方向性对正交材料动态裂纹生长的影响,并验证了所提框架的可靠性。Multifunctional composite material based on piezoelectric nanofibers and Cu-CFRP electrodes for sensing applicationsFrancesco Mongioì, Giacomo Selleri, Tommaso Maria Brugo, Emanuele Maccaferri, Davide Fabiani, Andrea Zucchellidoi:10.1016/j.compstruct.2024.118076基于压电纳米纤维和铜-CFRP 电极的多功能复合材料在传感应用中的应用To monitor possible failures of a composite, several Structural Health Monitoring (SHM) systems have been developed. However, these methods typically involve embedding commercial sensors within the laminate, potentially compromising the material's strength. In this study, a self-sensing composite laminate was fabricated by interleaving poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) piezoelectric nanofibers between Glass Fiber Reinforced Plastic (GFRP) prepreg plies. Instead of conventional metallic sheets, hybrid Copper-Carbon Fiber Reinforced Plastic (Cu-CFRP) was used as electrodes to collect piezoelectric signals. This innovative approach offers two main advantages: enhanced interlaminar fracture toughness due to nanometric piezoelectric fibers and an intrinsic connection between copper wires and carbon, eliminating the need for additional electrical cables within the laminate. The effect of stacking sequence parameters on the self-sensing laminate's electromechanical response was investigated using a Design of Experiment (DoE) based on the Box-Benken method. Additionally, a lumped electric circuit model was employed to gain analytical insights into the piezoelectric behavior of the laminates.为了监测复合材料可能出现的故障,人们开发了多种结构健康监测(SHM)系统。然而,这些方法通常需要在层压板中嵌入商用传感器,这可能会影响材料的强度。在本研究中,通过在玻璃纤维增强塑料(GFRP)预浸料层之间交错聚(偏氟乙烯-三氟乙烯)(P(VDF-TrFE))压电纳米纤维,制造了一种自传感复合材料层压板。铜-碳纤维增强塑料(Cu-CFRP)混合材料取代了传统的金属片,被用作收集压电信号的电极。这种创新方法具有两大优势:纳米压电纤维增强了层间断裂韧性;铜线与碳之间的内在联系消除了层压板内的额外电线。我们采用基于方框-本肯(Box-Benken)方法的实验设计(DoE)研究了堆叠顺序参数对自感应层压板机电响应的影响。此外,还采用了叠加电路模型来分析层压板的压电行为。Composites Part A: Applied Science and ManufacturingEffects of through-thickness dielectric sensor on carbon fibre epoxy cure monitoringMolly Hall, Xuesen Zeng, Tristan Shelley, Peter Schubeldoi:10.1016/j.compositesa.2024.108168穿透厚度介电传感器对碳纤维环氧树脂固化监测的影响Dielectric sensors are an appealing solution for in-situ cure monitoring of thermoset polymers and thermoset composites. Analysis techniques have been shown to produce highly accurate and repeatable insight into cure state metrics both during and after cure. However, most dielectric sensors only report data on the surface of the material the sensor is in direct contact with, neglecting the remainder of the thickness of the component. This study evaluates a novel dielectric sensor which is designed with a 20 mm penetration depth to monitor through the thickness of the composite part. While the prototype sensor design was shown to influence the raw data signal, a correction factor was successfully applied, and signals were analysed in accordance with the standard set of dielectric methods. The corrected signal had good accuracy and repeatability across laminates from 2 to 20 mm thick, demonstrating a non-invasive, through-thickness monitoring for a range of part designs.电介质传感器是对热固性聚合物和热固性复合材料进行现场固化监测的一种极具吸引力的解决方案。分析技术已被证明能够在固化过程中和固化后对固化状态指标进行高精度和可重复的深入分析。然而,大多数介电传感器只能报告与传感器直接接触的材料表面的数据,而忽略了部件厚度的其余部分。本研究对新型介电传感器进行了评估,该传感器的设计穿透深度为 20 毫米,可监测复合材料部件的整个厚度。虽然原型传感器的设计会影响原始数据信号,但还是成功应用了校正因子,并根据标准介电方法对信号进行了分析。校正后的信号在厚度从 2 毫米到 20 毫米的层压板上都具有良好的准确性和可重复性,证明了可对各种部件设计进行非侵入式厚度监测。Static and dynamic damping mechanical performance of architected metal-epoxy interpenetrating phase compositesAgyapal Singh, Nikolaos Karathanasopoulosdoi:10.1016/j.compositesa.2024.108171 架构金属-环氧互穿相复合材料的静态和动态阻尼机械性能The present contribution investigates the static and dynamic damping mechanical response of architected aluminum-epoxy interpenetrating phase composites (IPCs), engineered with strut, triply periodic minimal surfaces (TPMS), and stochastic spinodal AlSi10Mg reinforcement phases. Both single-phase metamaterials and co-continuous, multi-phase composites are analyzed, assessing the role of the reinforcement phase design and the addition of silicon carbide (SiC) nano-whisker epoxy enhancements in the effective mechanical performance. Aluminum-epoxy IPCs yield a constitutive response with peak, plateau stress, and overall energy absorptions up to 25 times higher than the ones recorded for the underlying single-phase metamaterials. Inner plastic strains, probed through dedicated finite element analysis, provide insights into the inner damage evolution, leading to characteristic ductile failure patterns, as revealed by computer tomography analysis. The exceptional specific energy absorption attributes are complemented by outstanding dynamic performance characteristics, with significant loss moduli over a broad range of frequencies and damping ratios up to 0.29.本论文研究了铝-环氧互穿相复合材料(IPCs)的静态和动态阻尼机械响应,该复合材料采用支杆、三重周期性最小表面(TPMS)和随机旋极 AlSi10Mg 增强相进行设计。分析了单相超材料和共连续多相复合材料,评估了增强相设计和添加碳化硅(SiC)纳米晶须环氧增强材料对有效机械性能的作用。铝-环氧 IPC 的峰值、高原应力和整体能量吸收的构成响应比底层单相超材料高出 25 倍。通过专门的有限元分析探究内部塑性应变,可以深入了解内部损伤的演变过程,从而形成计算机断层扫描分析所揭示的特征性韧性破坏模式。除了卓越的比能量吸收特性外,还具有出色的动态性能特征,在广泛的频率范围内具有显著的损耗模量,阻尼比高达 0.29。Composite phase change materials with room-temperature-flexibilityZaichao Li, Yuang Zhang, Xuan Wang, Feng Cao, Shufen Zhang, Bingtao Tangdoi:10.1016/j.compositesa.2024.108173 具有室温柔性的复合相变材料Phase change materials (PCMs) have attracted considerable attention for effectively addressing the problem of thermal energy supply–demand mismatch. However, the practical application of PCMs is still hindered by inherent challenges such as crystalline rigidity, leakage susceptibility, and poor thermal conductivity. In this research, on the basic of thermal control provided by phase change storage and the elastic behavior supported by thermoplastic polyester elastomer at room temperature, we fabricated a new type of composite PCM (CPCM) that exhibits flexibility even at room temperature. This CPCM demonstrates good shape and thermal stability. Furthermore, the carbon nanotubes-COOH modified with lauric acid (LA) can be uniformly dispersed within the CPCM matrix, thereby enhancing the thermal conductivity of the CPCM. Additionally, the composite material exhibits a promising thermal management performance for high-temperature lithium-ion (Li-ion) batteries. These findings open up new possibilities for the development of room- temperature flexible CPCMs.相变材料(PCM)能有效解决热能供需不匹配的问题,因此备受关注。然而,PCM 的实际应用仍然受到晶体刚性、易泄漏性和导热性差等固有挑战的阻碍。在这项研究中,我们以相变存储提供的热控制和热塑性聚酯弹性体在室温下支持的弹性行为为基础,制造了一种新型复合 PCM(CPCM),它在室温下也能表现出柔性。这种 CPCM 具有良好的形状和热稳定性。此外,用月桂酸(LA)改性的碳纳米管-COOH 可以均匀地分散在 CPCM 基体中,从而增强了 CPCM 的导热性。此外,这种复合材料在高温锂离子(Li-ion)电池的热管理方面表现出良好的性能。这些发现为室温柔性 CPCM 的开发提供了新的可能性。Lightweight, freestanding hybrids of graphene and hexagonal boron nitride foamsPatrick Ryan Galligan, Hongwei Liu, Guang Wang, Mohsen Tamtaji, Yaxuan Li, Tsz Wing Tang, Yanguang Zhou, Zhengtang Luodoi:10.1016/j.compositesa.2024.108176 石墨烯和六方氮化硼泡沫的轻质独立混合体Lightweight boron carbon nitride foams which are a hybrid of graphene and hexagonal boron nitride(hBN), are produced using the nickel template method and remain freestanding after the etching of nickel without the stabilization of a polymer during etching. Chemical vapor deposition (CVD) precursors with varying carbon content were utilized, but only a 10% range of carbon atomic percentage variation is observed in the resulting boron carbon nitride foams due to the high carbon solubility of nickel. However, the cooling rate during the CVD process has a much more significant effect on the carbon content. Moreover, a 6.5-fold increase in resistivity is observed for our foams compared to a graphene foam with an overall trend of decreasing resistance with increasing carbon content. Furthermore, when the foam is infiltrated with epoxy to form a composite at 0.3% volumetric percentage concentration, there is a 27% increase in the thermal conductivity over hBN foam composites. These foams are suitable to use as a substitute for graphene foams when a lower electrical conductivity is desired and could potentially be used as a thermal interface material if a higher pore density nickel template is utilized.轻质氮化硼碳泡沫是石墨烯和六方氮化硼(hBN)的混合体,采用镍模板法生产,镍蚀刻后仍保持独立,蚀刻过程中无需聚合物稳定。虽然使用了不同碳含量的化学气相沉积(CVD)前驱体,但由于镍的高碳溶解度,在生成的氮化硼泡沫中仅观察到 10%的碳原子百分比变化范围。然而,CVD 过程中的冷却速度对碳含量的影响要大得多。此外,与石墨烯泡沫相比,我们的泡沫的电阻率增加了 6.5 倍,总体趋势是电阻率随着碳含量的增加而降低。此外,当泡沫渗入环氧树脂形成体积百分比浓度为 0.3% 的复合材料时,导热系数比 hBN 泡沫复合材料增加了 27%。当需要较低的导电率时,这些泡沫可用作石墨烯泡沫的替代品,如果使用孔隙密度较高的镍模板,则有可能用作热界面材料。The delamination performance of composite laminates with bionic high toughness regionsXiao Yang, Guangji Li, Yu Chen, Shichao Niu, Honglie Song, Xianchang Peng, Pucun Bai, Jing Ni, Chun Shaodoi:10.1016/j.compositesa.2024.108172具有仿生高韧性区域的复合材料层压板的脱层性能Inspired by the composite structure of soft and hard phases found inbiological materials, this paper prepares the CF/PPS woven composite laminates with bionic high toughness regions to improve the delamination resistance. The optimal bionic high toughness regions can increase the flexural strength by 75% compared to Baseline. These bionic regions improve the delamination resistance via two mechanisms. i) The paths of crack change from interlaminar to intralaminar because of crack deflection, branching, and convergence. ii) The singular concentrations of interlaminar stress are improved by producing tiny cracks. Finally, the damage mode is investigated in details. It shows that the pure mode II failure is transformed into a mixture of mode I and mode II failures. The cracks are more likely to transition from interlaminar to intralaminar when the distribution of bionic regions is more dispersed. As a result of these regions, the catastrophic delamination failure is improved effectively.受生物材料中软硬相复合结构的启发,本文制备了具有仿生高韧性区域的 CF/PPS 编织复合材料层压板,以提高抗分层能力。与基线相比,最佳仿生高韧性区域可将抗弯强度提高 75%。i) 由于裂纹偏转、分支和汇聚,裂纹路径从层间变为层内。 ii) 通过产生微小裂纹,改善了层间应力的奇异集中。最后,对破坏模式进行了详细研究。结果表明,纯模式 II 破坏转变为模式 I 和模式 II 的混合破坏。当仿生区域分布更分散时,裂纹更有可能从层间过渡到层内。由于这些区域的存在,灾难性分层破坏得到了有效改善。Impact behaviour of 3D printed fiber reinforced cementitious composite beamsJinlong Pan, Pengxin Ping, Boyin Ding, Binrong Zhu, Yuanzheng Lin, Neven Ukrainczyk, Hong Zhang, Jingming Caidoi:10.1016/j.compositesa.2024.108175三维打印纤维增强水泥基复合梁的冲击性能Recent interest has grown in using 3D printing for military and civil defense engineering, particularly for infrastructure resilience against impacts. This study delves into the impact resistance of 3D printed fiber-reinforced cementitious composite (FRCC) beams. By analyzing varying fiber content, impact directions, and 3D printing nozzle sizes, the research found that the total energy dissipation of 3D printed FRCC beams was more than 40% higher and the 3D printed beams exhibited superior impact resistance compared to traditional beams, largely due to the fibers' role. The impact energy dissipation varied with different impact directions for the specimens, and the Z direction was identified as the most resistant, demonstrating anisotropic behavior in impact resistance. Smaller nozzle sizes in printing showed higher total energy dissipation, indicating increased impact resistance. X-ray analysis further revealed that the 3D printing process creates denser beams with better fiber–matrix adhesion and less porosity, improving overall impact resistance.最近,人们对将三维打印技术用于军事和民防工程,特别是用于基础设施的抗冲击能力越来越感兴趣。本研究深入探讨了三维打印纤维增强水泥基复合材料(FRCC)梁的抗冲击性。通过分析不同的纤维含量、冲击方向和三维打印喷嘴尺寸,研究发现三维打印纤维增强水泥基复合材料梁的总能量耗散比传统梁高 40% 以上,三维打印梁表现出更优越的抗冲击性能,这主要归功于纤维的作用。冲击能量耗散随试样的不同冲击方向而变化,Z 方向的抗冲击能力最强,这表明了抗冲击能力的各向异性。打印中喷嘴尺寸越小,总能量耗散越大,表明抗冲击性越强。X 射线分析进一步表明,三维打印工艺能产生密度更大的梁,纤维与基质的粘附性更好,孔隙率更低,从而提高了整体抗冲击性。The use of crude carbon dots as green, low-cost and multifunctional additives to improve the curing, mechanical, antioxidative and fluorescence properties of epoxy natural rubber/silica compositesChaoying Sun, Liwei Li, Haijun Ji, Hui Yang, Guangzhi Jin, Can Jiang, Pingyun Guo, Liqun Zhang, Peng Yu, Runguo Wangdoi:10.1016/j.compositesa.2024.108177 使用粗碳点作为绿色、低成本和多功能添加剂,改善环氧天然橡胶/二氧化硅复合材料的固化、机械、抗氧化和荧光特性Rubbers are acknowledged as strategically important and irreplaceable materials in daily life, and rubber additives are indispensable components for the practical application of the rubber vulcanizate. Developing novel rubber additives is highly desirable, and pursuing multifunctional rubber additives has been one of the major tasks in the field of rubber. Herein, the crude carbon dots (CCDs) without any purification were used as rubber additives for epoxy natural rubber/silica system by conventional milling process. Our results revealed that the CCDs have outstanding advantages, they could not only endow the rubber with charming fluorescence and excellent anti-aging capability, but also improve the curing rate and mechanical performance of rubber composite. Moreover, with the incorporation of CCDs, the rolling resistance of the rubber composite could be remarkably reduced, which is promising for the application of green tyres. Overall, this work convincingly provides novel inspiration to develop novel low-cost yet multifunctional additives for rubber.橡胶是公认的具有重要战略意义且在日常生活中不可替代的材料,而橡胶添加剂则是橡胶硫化剂实际应用中不可或缺的成分。开发新型橡胶添加剂是非常有必要的,而追求橡胶添加剂的多功能性一直是橡胶领域的主要任务之一。本文采用传统研磨工艺,将未经任何提纯的粗碳点(CCD)用作环氧天然橡胶/二氧化硅体系的橡胶添加剂。结果表明,CCDs 具有突出的优点,不仅能赋予橡胶迷人的荧光和优异的抗老化能力,还能提高橡胶复合材料的硫化速度和机械性能。此外,CCD 的加入还能显著降低橡胶复合材料的滚动阻力,为绿色轮胎的应用带来了希望。总之,这项研究为开发新型低成本多功能橡胶添加剂提供了新的灵感。Composites Part B: EngineeringA 3D voxel-based mesostructure generator for finite element modelling of tow-based discontinuous compositesLuis Gulfo, Olle Haglund Nilsson, Jacob Sjöberg, Ioannis Katsivalis, Leif E. Asp, Martin Fagerströmdoi:10.1016/j.compositesb.2024.111405基于三维体素的网格结构生成器,用于对拖缆式非连续复合材料进行有限元建模Tow-based discontinuous composites manufactured with ultra-thin tapes display high stiffness, strength, and in-plane isotropy, thus competing with composite laminates. Their complex 3D microstructure affects the mechanical response, in turn demanding 3D generators that capture the tape waviness, resin pockets, and thickness and fibre content variations. The present work proposes an automated numerical framework combining a 3D voxel-based mesostructure generator with finite element models. A modified 3D random sequential absorption technique is developed with bin-guided allocation, draping, and thickness control. A statistical study is used to size the statistical volume elements and predict the elastic properties of thick, thin, and ultra-thin tow-based discontinuous composites. The results are compared with the experimental values from the literature. Despite uncertainties in physical tape properties, the resulting stiffnesses are predicted with good accuracy.用超薄带制造的纤网基非连续复合材料具有很高的刚度、强度和面内各向同性,因此可与复合材料层压板相媲美。其复杂的三维微观结构会影响机械响应,因此需要三维生成器来捕捉带状波纹、树脂袋以及厚度和纤维含量的变化。本研究提出了一种自动数值框架,将基于三维体素的中观结构生成器与有限元模型相结合。开发了一种改进的三维随机顺序吸收技术,该技术具有仓引导分配、悬垂和厚度控制功能。统计研究用于确定统计体积元素的大小,并预测厚、薄和超薄丝束基非连续复合材料的弹性特性。研究结果与文献中的实验值进行了比较。尽管物理丝带特性存在不确定性,但所得到的刚度预测准确度很高。Composites Science and TechnologyGreen synthesis of positive electrodes for high performance structural batteries - A study on graphene additivesZhenyuan Xia, Zhaoyang Li, Johanna Xu, Sankar Sasidharan, Jaime S. Sanchez, Vincenzo Palermo, Leif E. Aspdoi:10.1016/j.compscitech.2024.110568 高性能结构电池正极的绿色合成--关于石墨烯添加剂的研究Carbon fibres (CF) have the potential to serve as versatile and multifunctional conductive electrodes within the concept of “structural batteries”. These batteries possess the unique ability to both store electrical energy and bear mechanical loads without requiring extra current collectors. However, numerous challenges remain on the path to commercializing structural batteries. One significant challenge lies in the fabrication process of CF-based cathode composites, including the poor adhesion of active materials to the CF surface and the use of hazardous organic solvents, such as N-methyl pyrrolidone (NMP) through traditional blade coating. In this study, we present a sustainable fabrication approach, using electrophoretic deposition (EPD) to construct positive electrode composites with lithium iron phosphate (LiFePO4) and graphene nanosheets. Especially, ethanol was used as a green solvent replacing NMP to minimize the environmental impact. Meanwhile, the influence of different types of graphene additives (three kinds of graphene nanoplatelets (GNP), four kinds of reduced graphene oxide (rGO) and one home-made graphene) to the relative battery performance were evaluated under a systematic comparative analysis. Among the tested graphene additives, LFP/rGO2 based positive electrode exhibits a desirable specific capacity of 126.2 mAhg−1, maintaining over 93% retention even under the demanding conditions of 2C over 500 cycles.在 "结构电池 "概念中,碳纤维(CF)具有作为多功能导电电极的潜力。这些电池具有独特的能力,既能储存电能,又能承受机械负载,而无需额外的电流收集器。然而,在实现结构电池商业化的道路上仍存在诸多挑战。其中一个重大挑战在于基于 CF 的阴极复合材料的制造工艺,包括活性材料与 CF 表面的粘附性差,以及通过传统的叶片涂层使用 N-甲基吡咯烷酮(NMP)等有害有机溶剂。在本研究中,我们提出了一种可持续的制造方法,即使用电泳沉积(EPD)来构建磷酸铁锂(LiFePO4)和石墨烯纳米片的正极复合材料。特别是使用乙醇作为绿色溶剂替代 NMP,以最大限度地减少对环境的影响。同时,通过系统比较分析,评估了不同类型的石墨烯添加剂(三种石墨烯纳米片(GNP)、四种还原氧化石墨烯(rGO)和一种自制石墨烯)对相对电池性能的影响。在测试的石墨烯添加剂中,基于 LFP/rGO2 的正极表现出 126.2 mAhg-1 的理想比容量,即使在 500 次以上的 2C 苛刻条件下也能保持 93% 以上的保持率。Anisotropic elastoplasticity and fracture of SCFR-PEEK composites in complex biaxial loading: Experiments and modellingWencheng Liu, Jinlong Liu, Xinghao Li, Jia Huang, Yang Chen, Yulong Li, Jun Ma, Hao Cuidoi:10.1016/j.compscitech.2024.110569 复杂双轴加载条件下 SCFR-PEEK 复合材料的各向异性弹塑性和断裂:实验与建模This research aims to gain insight into the anisotropic deformation and fracture behaviours of short carbon fibre reinforced polyether-ether ketone composites (SCFR-PEEK) under complex loading using experimental and modelling approaches. Novel biaxial tensile experiments using optimised cruciform specimens are designed and performed to study the anisotropic elastoplasticity and fracture behaviours of SCFR-PEEK in various stress states. An advanced anisotropic constitutive model was developed, experimentally calibrated, numerically implemented, and successfully verified by mechanical responses of biaxial tension with various stress ratios. Furthermore, using a hybrid experimental-numerical approach, the biaxial failure stress at crack initiation sites captured by a high-speed camera in biaxial tension was obtained. Employing experimental failure stresses at various uniaxial and biaxial stress states, a maximum stress based failure criterion was developed, which is coupled with the anisotropic elastoplastic model, thus enabling the description the anisotropic elastoplastic and failure behaviours under complex loading. The prediction of the failure of SCFR-PEEK in complex biaxial stress states using the coupled model is in good agreement with biaxial tensile experimental results using circular-notched specimens. Therefore, the developed model is verified to be capable of describing both elastoplastic deformation and fracture failure behaviours of SCFR-PEEK composites in complex loading.本研究旨在利用实验和建模方法深入了解短碳纤维增强聚醚醚酮复合材料(SCFR-PEEK)在复杂载荷下的各向异性变形和断裂行为。利用优化的十字形试样设计并进行了新型双轴拉伸实验,以研究 SCFR-PEEK 在各种应力状态下的各向异性弹塑性和断裂行为。开发了一种先进的各向异性构成模型,对其进行了实验校准和数值计算,并通过各种应力比的双轴拉伸机械响应进行了成功验证。此外,利用实验-数值混合方法,获得了高速摄像机捕捉到的双轴拉伸下裂纹起始点的双轴破坏应力。利用各种单轴和双轴应力状态下的实验破坏应力,制定了基于最大应力的破坏准则,该准则与各向异性弹塑性模型相结合,从而能够描述复杂加载下的各向异性弹塑性和破坏行为。使用耦合模型对 SCFR-PEEK 在复杂双轴应力状态下的破坏进行的预测与使用圆形缺口试样进行的双轴拉伸实验结果非常吻合。因此,验证了所开发的模型能够描述复杂加载下 SCFR-PEEK 复合材料的弹塑性变形和断裂失效行为。Balancing creep resistance and resilience in composites: Leveraging multidirectional and hierarchical structure of collagen fibresChao Lei, Weixing Xu, Yunhang Zeng, Jibo Zhou, Bi Shidoi:10.1016/j.compscitech.2024.110570 平衡复合材料的抗蠕变性和回弹性:利用胶原纤维的多向和分层结构Conventional methods of enhancing the creep resistance of polyvinyl chloride (PVC) often compromise its resilience. This study proposes a novel strategy to achieve a balance between creep resistance and resilience in PVC-matrix composites by incorporating epoxidised soybean oil-modified collagen fibres (MCFs). A comparative analysis of creep and recovery behaviour was conducted among MCF/PVC, pure PVC, and other conventional modified systems. Results revealed that MCF/PVC exhibited a lower total creep strain (12.82%) than pure PVC and a higher recoverable deformation (10.80%) than the other conventional modified systems. Moreover, MCF/PVC had the longest predicted creep lifetime among all the modification systems, which was 103 times longer than that of pure PVC. These improvements were attributed to the natural multidirectional and hierarchical structure of MCF, which hindered the movement of PVC chains and provided sufficient gaps for recoverable deformation. This work provides a new perspective on developing resilient creep-resistant modifications of polymers by leveraging the structural advantages of natural products.增强聚氯乙烯(PVC)抗蠕变性的传统方法往往会损害其回弹性。本研究提出了一种新策略,通过加入环氧化大豆油改性胶原纤维(MCF),在 PVC 基质复合材料中实现抗蠕变性和回弹性之间的平衡。对 MCF/PVC、纯 PVC 和其他传统改性体系的蠕变和恢复行为进行了比较分析。结果显示,MCF/PVC 的总蠕变应变(12.82%)低于纯 PVC,而可恢复变形(10.80%)则高于其他传统改性体系。此外,在所有改性体系中,MCF/PVC 的预测蠕变寿命最长,是纯 PVC 的 103 倍。这些改进归功于 MCF 的天然多向分层结构,它阻碍了聚氯乙烯链的运动,并为可恢复变形提供了足够的间隙。这项研究为利用天然产品的结构优势开发弹性抗蠕变改性聚合物提供了新的视角。Synergistic interactions of citric acid grafted β-cyclodextrin and polyethyleneimine for improving interfacial properties of basalt fiber/epoxy compositesQing Wu, Renjie Yao, Hao Deng, Bolin Xiao, Ziyi Ye, Yating Li, Jianfeng Zhudoi:10.1016/j.compscitech.2024.110575 柠檬酸接枝β-环糊精和聚乙烯亚胺的协同作用改善玄武岩纤维/环氧树脂复合材料的界面性能Basalt fiber responds well to the global concept of environmental protection due to its attractive superiorities of green and excellent mechanical performance. However, the ultra-low interfacial adhesion strength of fiber-to-matrix deeply restricts its wide application. Moreover, attempts to utilize natural- or bio-materials on basalt fiber towards growth in interfacial adhesion remains in its infancy, if feasible, it would make green materials shine brilliantly. Herein, we install citric acid modified β-cyclodextrin (β-CD) and polyethyleneimine (PEI) on basalt fiber via dipping approach for the first time, which results in 76.9% increment in fiber-to-epoxy adhesion over control fiber. Unique inner hydrophobic and outer hydrophilic conical cavity architecture of β-CD endows interphase with dense ring hydrogen bond band “core”- covalent/ionic bonding “shell” multiple interactions that balance stress transfer and energy dissipation. Additionally, “rigid” β-CD and “flexible” PEI function as crack deflection and stress distribution for gaining stronger interphase of basalt fiber composites. This paper serves to provide a new exploitation for advancing green and high-performance composites.玄武岩纤维因其绿色环保和优异的机械性能而深受全球环保理念的青睐。然而,纤维与基体之间超低的界面粘附强度深深限制了它的广泛应用。此外,在玄武岩纤维上利用天然或生物材料提高界面粘附力的尝试仍处于起步阶段,如果可行,将使绿色材料大放异彩。在本文中,我们首次通过浸渍法在玄武岩纤维上安装了柠檬酸改性的β-环糊精(β-CD)和聚乙烯亚胺(PEI),与对照纤维相比,纤维与环氧树脂的粘附力提高了 76.9%。β-CD独特的内疏水、外亲水的锥形空腔结构,使相间具有致密的环状氢键带 "核"-共价/离子键 "壳 "多重相互作用,从而平衡了应力传递和能量耗散。此外,"刚性 "β-CD 和 "柔性 "PEI 还能起到裂纹偏转和应力分布的作用,从而增强玄武岩纤维复合材料相间的强度。本文为推动绿色高性能复合材料的发展提供了新的思路。Hybrid cross-linking for the synthesis of highly tough fluorescent alginate fibersDongnan Zhang, Hong Zhang, Song Tang, Zijian Bai, Jianyu Jiang, Yao Wang, Yue Yu, Fengyu Quandoi:10.1016/j.compscitech.2024.110577 用于合成高韧性荧光藻酸盐纤维的混合交联技术The limited mechanical performance and functional constraints of alginate fibers significantly impede their development in the context of professional research. To address the aforementioned issues, this study initially utilized polyethyleneimine (PEI) and citric acid to synthesize carbon quantum dots (CD) with surface amino functionalization. Subsequently, in a sodium alginate (SA) solution, CD and vinyl silicon-based nanoparticles (VSNP) were co-introduced. Utilizing the abundant hydroxyl and carboxyl groups in polysaccharides, stable interactions were achieved with CD and VSNP. Incorporating a dynamic hydrogen-bonded crosslinking network among CD, VSNP and SA, the establishment of a calcium alginate (CA) ionically crosslinked network is facilitated via calcium-sodium ion exchange. Additionally, the interwoven and interlocked structure between the aforementioned dual networks was established. Employing a wet spinning process, the synergistic multiple dynamic energy dissipation mechanisms significantly enhance the mechanical performance. Fluorescent alginate fibers (CA/VSNP/CD) were prepared. The tensile strength was 3.81 cN/dtex, and the elongation at break was 13.16%. Compared to pure CA fibers, there were respective increases of 95.38% and 82.02%. Simultaneously, the fibers exhibit excitation-dependent emission characteristics. This work lays the foundation for potential applications of fluorescent alginate fibers in environmental monitoring, chemical sensors, dynamic anti-counterfeiting, and biomedical fields.海藻酸纤维有限的机械性能和功能限制极大地阻碍了其在专业研究领域的发展。针对上述问题,本研究首先利用聚乙烯亚胺(PEI)和柠檬酸合成了表面氨基官能化的碳量子点(CD)。随后,在海藻酸钠(SA)溶液中,CD 和乙烯基硅基纳米粒子(VSNP)被共同引入。利用多糖中丰富的羟基和羧基,CD 和 VSNP 实现了稳定的相互作用。在 CD、VSNP 和 SA 之间加入动态氢键交联网络,通过钙钠离子交换促进藻酸钙(CA)离子交联网络的建立。此外,还建立了上述双网络之间的交织和互锁结构。采用湿法纺丝工艺,协同多重动态消能机制显著提高了机械性能。制备出了荧光藻酸盐纤维(CA/VSNP/CD)。拉伸强度为 3.81 cN/dtex,断裂伸长率为 13.16%。与纯 CA 纤维相比,分别提高了 95.38% 和 82.02%。同时,这种纤维还表现出与激发相关的发射特性。这项工作为荧光藻酸盐纤维在环境监测、化学传感器、动态防伪和生物医学领域的潜在应用奠定了基础。Liquid metal-modified boron nitride for polytetrafluoroethylene composites with enhanced thermal conductivity and peel strengthRui Xue, Zilong Xie, Songgang Chai, Tianhao Yang, Rui Feng, Lu He, Kai Wu, Qin Zhang, Qiang Fudoi:10.1016/j.compscitech.2024.110572 用于聚四氟乙烯复合材料的液态金属改性氮化硼,可增强导热性和剥离强度Polytetrafluoroethylene (PTFE)/boron nitride (BN) composites has ultra-low dielectric loss and thermal conductivity, making it a suitable choice for high-frequency communication copper-clad laminate. However, the low peel strengthens of these composites restricted the further application, due to the low polarity and smooth surface of BN. Here, we assemble liquid metal (LM) on BN filler (LM-BN) via a mechanochemistry method. The surface polarity and roughness of BN can be enhanced by the oxidized layer from LM. The thermal interfacial overlap between BN sheets can be enhanced by LM droplets. Consequently, at filler content of 50 vol%, the thermal conductivity increases from 0.3 W/m⋅K of PTFE to 1.90 W/m⋅K for PTFE/BN composites, to 2.05 W/m⋅K for PTFE/LM-BN composites, and the peel strength exhibit a nearly 100% increment from 0.19 of PTFE/BN to 0.39 N/mm of PTFE/LM-BN. Along with low dielectric loss, excellent thermal conductivity, peel strength, and reduced thermal expansion, this method ensures a wider application of PTFE/LM-BN composites in electronic packaging.聚四氟乙烯(PTFE)/氮化硼(BN)复合材料具有超低的介电损耗和热导率,是高频通信铜箔层压板的理想选择。然而,由于 BN 的极性低且表面光滑,这些复合材料的剥离强度低,限制了其进一步应用。在此,我们通过机械化学方法在 BN 填料上组装液态金属(LM)(LM-BN)。液态金属氧化层可增强 BN 的表面极性和粗糙度。LM 液滴可增强 BN 片材之间的热界面重叠。因此,当填料含量为 50 Vol% 时,导热系数从 PTFE 的 0.3 W/m⋅K 增加到 PTFE/BN 复合材料的 1.90 W/m⋅K,再到 PTFE/LM-BN 复合材料的 2.05 W/m⋅K,剥离强度从 PTFE/BN 的 0.19 增加到 PTFE/LM-BN 的 0.39 N/mm,增幅接近 100%。该方法具有低介电损耗、优异的导热性、剥离强度和较低的热膨胀率,可确保 PTFE/LM-BN 复合材料在电子封装中得到更广泛的应用。来源:复合材料力学仿真Composites FEM

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