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【新文速递】2024年4月1日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 2 篇

International Journal of Solids and Structures

A comprehensive investigation of the lattice structure mechanical properties based on schwarz primitive triply periodic minimal surface: Elastic modulus, yield strength, and maximum bearing force in the elastic region

Amin Dadashi, Gholamhossein Rahimi

doi:10.1016/j.ijsolstr.2024.112776

基于施瓦茨基元三周期极小面的晶格结构力学特性综合研究:弹性区域的弹性模量、屈服强度和最大承载力

Due to ongoing investigations, the potential for using triply periodic minimal surface (TPMS) lattice structures in various industries has been increased. The analytical relationships that determine the mechanical properties of these structures make cost-effective designs achievable for designers. In this study, a comprehensive investigation that includes analytical, numerical, and experimental approaches to determine the mechanical properties of the Primitive triply periodic minimal surface (P-TPMS) lattice structure under unidirectional loading was performed. The innovation of this paper is the derivation of analytical relationships of mechanical properties, including elastic modulus, yield strength, and maximum load-bearing force in the elastic region in terms of geometrical parameters of Primitive unit cell and properties of the constituent materials. These mechanical properties were obtained using the energy method and Euler-Bernoulli beam theory for relative densities in the range of 0.24–0.76. Relative density was determined based on the geometric parameter of the surface size (m). In addition, the lattice structures were fabricated additively manufactured, and compressive test experiments were conducted. The mechanical properties of P-TPMS lattice structures vary dramatically with varying surface size values, according to the study's findings. The P-TPMS lattice structure's elastic modulus and yield strength at m=0.35 are more than 11 and 32 times larger, respectively than the yield stress and elastic modulus at m=0.65. The unit cell's length has no bearing on the elastic modulus or yield strength.

随着研究的不断深入,三重周期性最小表面(TPMS)晶格结构在各行各业的应用潜力不断增加。确定这些结构机械性能的分析关系使得设计人员可以进行经济有效的设计。本研究通过分析、数值和实验等方法对原始三周期极小面(P-TPMS)晶格结构在单向载荷下的力学性能进行了全面研究。本文的创新之处在于根据原始单元格的几何参数和组成材料的特性,推导出机械特性的分析关系,包括弹性模量、屈服强度和弹性区域的最大承载力。这些力学性能是在相对密度为 0.24-0.76 的范围内,利用能量法和欧拉-伯努利梁理论获得的。相对密度是根据表面尺寸(m)的几何参数确定的。此外,还采用添加法制造了晶格结构,并进行了抗压测试实验。研究结果表明,随着表面尺寸值的变化,P-TPMS 晶格结构的机械性能也会发生显著变化。m=0.35 时,P-TPMS 晶格结构的弹性模量和屈服强度分别比 m=0.65 时的屈服应力和弹性模量大 11 倍和 32 倍以上。单元格的长度对弹性模量和屈服强度没有影响。


International Journal of Plasticity

Exceptional ductility through interface-constrained grain growth for the ultrafine-scale Ni/Ni-W layered composites

Fei Liang, Zhe-Xuan Wang, Mei-Yue Li, Bin Zhang, Xue-Mei Luo, Xiao-Fei Zhu, Guang-Ping Zhang

doi:10.1016/j.ijplas.2024.103959

通过界面约束晶粒生长实现超细镍/镍-钨层状复合材料的优异延展性

Enhancing the strength of metallic laminates through decreasing the constituent layer thickness from micrometer to nanometer scale is usually accompanied by the degradation of ductility because plastic instability characterized by fatal shear bands inevitably occurs in the early stage of deformation. To overcome the strength-ductility trade-off dilemma, we designed a kind of metallic layered composites (LCs) consisting of nano-grained Ni (grain size: 21-37 nm) and ultrafine nano-grained Ni-W (grain size: 8 nm) constituent layers with layer thickness ranging from microns to tens of nanometers. We found that the strength and ductility of Ni/Ni-W LCs can be simultaneously enhanced by decreasing the layer thickness. Interface-constrained grain growth in the Ni layers with an initial layer thickness of less than 1 μm enhances strain hardening ability. Thus, strain delocalization characterized by the formation of rectangular strain zones instead of crossed micro shear bands appears in the LCs. Based on the above mechanism, we obtained the optimum ratio of the layer thickness to the grain size for the nano-grained Ni layers as about 15:1, which corresponds to Ni0.25/Ni-W0.025 LCs with the highest tensile strength (1.9 GPa) and elongation to failure (5.5%). These findings may provide a new path for the design principle of metallic LCs with multi-level microstructural and geometrical scales.

通过将组成层的厚度从微米级减小到纳米级来提高金属层压材料的强度,通常会伴随着延展性的降低,因为在变形早期不可避免地会出现以致命剪切带为特征的塑性不稳定性。为了克服强度-延展性权衡的难题,我们设计了一种由纳米级镍(晶粒尺寸:21-37 纳米)和超细纳米级镍-钨(晶粒尺寸:8 纳米)组成的金属层状复合材料(LCs),层厚从微米到数十纳米不等。我们发现,通过减小层厚度,Ni/Ni-W LCs 的强度和延展性可同时得到提高。初始层厚小于 1 μm 的镍层中的界面约束晶粒生长可增强应变硬化能力。因此,低密度层中出现了以形成矩形应变区而不是交叉微剪切带为特征的应变分散。根据上述机理,我们得到了纳米晶粒镍层的最佳层厚与晶粒大小比约为 15:1,对应于具有最高拉伸强度(1.9 GPa)和破坏伸长率(5.5%)的 Ni0.25/Ni-W0.025 LCs。这些发现可能会为具有多级微结构和几何尺度的金属 LCs 的设计原理提供一条新的途径。


Thin-Walled Structures

WELDED BEAM-TO-COLUMN STEEL JOINTS: ASSESSMENT OF EUROPEAN DESIGN RULES

Jorge Conde, Fernando Freire, Filip Ljubinković, Martin Vild, Luís Simões da Silva

doi:10.1016/j.tws.2024.111844

梁与柱的焊接钢接头:欧洲设计规则评估

Properly validated high-quality Finite Element (FE) models with experimental tests permit an accurate description of the load-deformation path and stress state of steel joints and are nowadays accepted as “experimental results”. Changes to the design of welded joints in Eurocode 3 are currently proposed that affect the resistance and stiffness of the components associated with the column web panel. This paper presents an assessment of the design formulations included in the current Eurocode 3, part 1-8, and its forthcoming update in terms of stiffness and moment resistance, compared against a large parametric study of strong-axis beam-column welded joints for open sections carried out using validated sophisticated FE models. The results show that both the old and new Eurocode formulations provide a large scatter and no big differences between both methods. Additionally, the presence of axial force in the column shows a clear increase in the ratio between design resistance vs numerical resistance that, particularly in the case of transversally stiffened joints, may be unconservative.

经过适当验证的高质量有限元 (FE) 模型与实验测试可以准确描述钢接头的载荷变形路径和应力状态,如今已被公认为 "实验结果"。目前,欧洲规范 3 对焊接接头的设计提出了修改建议,这将影响与柱腹板相关部件的阻力和刚度。本文介绍了对现行 Eurocode 3 第 1-8 部分及其即将更新的刚度和抗弯矩设计方案的评估,并与使用经过验证的复杂 FE 模型对开放截面的强轴梁-柱焊接接头进行的大型参数研究进行了比较。研究结果表明,新旧欧洲规范的计算方法存在较大差异,两种方法之间没有明显区别。此外,柱中轴向力的存在明显增加了设计阻力与数值阻力之间的比率,特别是在横向加固接头的情况下,这可能是不可靠的。


Experimental and numerical investigation of through-diaphragm in H-shaped steel beam to CFST column connections

YongHyun Cho, Fangying Wang, SooYeon Seo, KangSeok Lee, TaeSoo Kim

doi:10.1016/j.tws.2024.111852

H 型钢梁与 CFST 柱连接中贯穿隔膜的实验和数值研究

This research proposes a cruciform through-diaphragm (CTD) for an H-shaped steel beam to concrete-filled steel tubular (CFST) column and investigates its seismic performance experimentally and numerically. The proposed connection consists of through-plates passing through the aligned slots in the panel zone and end plates directly welded to an H-shaped steel beam. This connection eliminates welding inside the steel tube for installation of the diaphragm, while providing a reliable load path from the steel beam to the CFST column. The experimental program examined the connection hysteretic behaviors, including the moment-rotation response, ductility, initial stiffness, and energy dissipation capacity. The proposed connection shows stable hysteric behavior and good energy dissipation up to a story drift up to 4% and satisfies the AISC seismic provisions criteria for special moment connection. A finite element (FE) model was established and verified against the experimental results. The effects of concrete infill, steel tube column thickness, axial load ratio, and through-plate thickness on the hysteretic behavior of the proposed connection were investigated through parametric analysis of 24 FE models. This study provides the information on the optimized design parameters that ensures the stable seismic performance of the proposed connection that could be used in structural engineering practice.

本研究提出了一种用于 H 型钢梁与混凝土填充钢管(CFST)柱的十字形贯穿隔膜(CTD),并对其抗震性能进行了实验和数值研究。拟议的连接由穿过面板区对齐槽的通板和直接焊接到 H 型钢梁上的端板组成。这种连接方式省去了在钢管内焊接安装隔膜的工序,同时提供了从钢梁到 CFST 柱的可靠载荷路径。实验程序检查了连接的滞后行为,包括力矩旋转响应、延展性、初始刚度和耗能能力。拟议的连接显示出稳定的滞回行为和良好的消能能力,可承受高达 4% 的楼层漂移,并满足 AISC 抗震规定中关于特殊弯矩连接的标准。建立了一个有限元(FE)模型,并根据实验结果进行了验证。通过对 24 个有限元模型进行参数分析,研究了混凝土填充、钢管柱厚度、轴向荷载比和通板厚度对拟议连接滞回行为的影响。这项研究提供了优化设计参数的信息,以确保所提连接具有稳定的抗震性能,可用于结构工程实践。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveDeform复合材料UG焊接理论材料
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首次发布时间:2024-11-13
最近编辑:11天前
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【新文速递】2024年4月4日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 2 篇Composite StructuresFailure prediction and optimization for composite pressure vessel combining FEM simulation and machine learning approachQingfeng Wang, Huasong Qin, Liyong Jia, Ziyi Li, Guoqiang Zhang, Yushu Li, Yilun Liudoi:10.1016/j.compstruct.2024.118099结合有限元模拟和机器学习方法进行复合材料压力容器的失效预测和优化Failure assessment is one of the fundamental tasks for optimization of composite pressure vessels (CPVs). However, the extensive design space of composites usually leads to costly and repetitive work of failure assessment that hinders the design and optimization of CPVs. In this work, a combined FEM simulation and machine learning approach is used to predict the failure factors R of CPVs for further optimization. CPVs with various design parameters are automatically generated and analyzed in ABAQUS to obtain failure factors under various external loadings. Then, an assembled deep neural network (DNN) namely Multi-DNN is trained to map relations between design parameters and R of CPVs. Further, transfer learning (TL) is introduced to improve the extensibility of our approach by fine-tuning the pre-trained Multi-DNN using scarce data of new design space. Such a TL-Multi-DNN model can precisely predict R of CPVs with new design parameters. Additionally, combining the trained models and genetic algorithm, the optimization of CPVs is carried out with high efficiency and low computational cost. As a result, R of CPV with various given and new design parameters can be estimated directly by the trained models and the optimal layer sequence of CPV can be obtained efficiently.失效评估是优化复合材料压力容器(CPV)的基本任务之一。然而,由于复合材料的设计空间很大,通常会导致失效评估工作的高成本和重复性,从而阻碍了 CPV 的设计和优化。本研究采用有限元模拟和机器学习相结合的方法来预测 CPV 的失效系数 R,以便进一步优化。在 ABAQUS 中自动生成具有各种设计参数的 CPV,并对其进行分析,以获得各种外部负载下的失效系数。然后,训练组装的深度神经网络(DNN),即 Multi-DNN,以映射 CPV 的设计参数和 R 之间的关系。此外,我们还引入了迁移学习(TL),利用新设计空间的稀缺数据对预先训练好的多重 DNN 进行微调,从而提高我们方法的可扩展性。这样的 TL-Multi-DNN 模型可以精确预测具有新设计参数的 CPV 的 R。此外,将训练好的模型与遗传算法相结合,可以高效率、低计算成本地优化 CPV。因此,经过训练的模型可以直接估算出具有各种给定参数和新设计参数的 CPV R,并高效地获得 CPV 的最佳层序。Auxetic lattice structures consisting of an enhanced trigram frame unit cell with superior stiffnessMohammad Bashtani, Ehsan Etemadi, Hong Hu, Mahmoud Moradidoi:10.1016/j.compstruct.2024.118100由具有超强刚度的增强型三叉框单元格组成的辅助晶格结构Superior stiffness is deemed essential for structures intended for several applications. The stiffness enhancement can be achieved by adopting structures that deform based on the stretching-dominated mechanism instead of the bending-dominated mechanism. This paper proposes a novel auxetic unit cell design and two distinct lattice structures dominated by stretching when subjected to quasi-static compressive and tensile loadings. The structures are manufactured via the fused deposition modeling (FDM) 3D printing method with the use of polylactic acid (PLA) filament as the patent material. The investigation also includes theoretical analyses and finite element (FE) simulations, all yielding consistent results. Response Surface Methodology (RSM) is also employed to understand the influence of three geometric parameters. Besides, single-objective optimization is conducted to maximize the stiffness through geometry design, and multi-objective approaches are implemented to improve the stiffness while simultaneously reducing relative density. Finally, different unit cells, which deform based on the stretching-dominated mechanism, are selected to represent their respective classifications, enabling a comparison of their potential stiffness capacity with the designed structures in this study. Remarkably, it is highlighted that the proposed unit cells and structures outperform others in terms of specific stiffness, making them a promising choice for use in structural engineering.对于一些应用领域的结构来说,卓越的刚度是必不可少的。通过采用以拉伸为主的变形机制而不是以弯曲为主的变形机制的结构,可以提高刚度。本文提出了一种新颖的辅助晶胞设计和两种不同的晶格结构,在承受准静态压缩和拉伸载荷时以拉伸为主。这些结构是通过熔融沉积建模(FDM)三维打印方法制造的,使用聚乳酸(PLA)长丝作为专利材料。调查还包括理论分析和有限元(FE)模拟,所有结果都是一致的。研究还采用了响应面方法(RSM)来了解三个几何参数的影响。此外,还进行了单目标优化,通过几何设计最大限度地提高刚度,并采用多目标方法在提高刚度的同时降低相对密度。最后,选择了基于拉伸主导机制变形的不同单元格来代表其各自的分类,从而将其潜在的刚度能力与本研究中设计的结构进行比较。值得注意的是,所提出的单元格和结构在特定刚度方面优于其他结构,使其成为结构工程中的理想选择。Multiscale mechanical analysis of 3D nanoparticle-reinforced metal-based composites considering interface effectsYongchao Zhang, Xiaotian Wang, Bin Li, Fangxin Wang, Xiaofan Goudoi:10.1016/j.compstruct.2024.118092考虑界面效应的三维纳米粒子增强金属基复合材料的多尺度力学分析Nanoparticle-reinforced metal-based composites (NRMCs) have gained recognition for their remarkable interface effects and their demonstration of superior mechanical properties. To effectively account for interfacial effects and precisely assess the mechanical properties of NRMCs with arbitrarily complex internal structures, our study employs the principle of minimum energy and leverages the Gurtin-Murdoch interface theory to devise a finite element interface element that comprehensively considers the interface effect of NRMCs. Utilizing this novel interface element, we construct diverse NRMCs model and subject them to single-axis tension and compression simulations. Our findings reveal that the developed finite element model accurately captures the internal stress distribution of the NRMCs. Both the particle modulus and interfacial effects exert influence on the Young’s modulus of the model. When the particle modulus is small, interfacial effects have a large impact on Young’s modulus. Additionally, the effect of interface residual stress on Young’s modulus is strongly dependent on the direction of external loading. The developed finite element model offers a scientific approach for accurately predicting the mechanical performance of NRMCs.纳米粒子增强金属基复合材料(NRMC)因其显著的界面效应和卓越的力学性能而获得广泛认可。为了有效考虑界面效应并精确评估具有任意复杂内部结构的 NRMC 的力学性能,我们的研究采用了最小能量原理,并利用 Gurtin-Murdoch 界面理论设计了一种有限元界面元素,全面考虑了 NRMC 的界面效应。利用这种新型界面元素,我们构建了多种 NRMC 模型,并对其进行了单轴拉伸和压缩模拟。研究结果表明,所开发的有限元模型能准确捕捉 NRMCs 的内部应力分布。颗粒模量和界面效应都会对模型的杨氏模量产生影响。当颗粒模量较小时,界面效应对杨氏模量的影响较大。此外,界面残余应力对杨氏模量的影响与外部加载方向密切相关。所开发的有限元模型为准确预测非弹性体材料的机械性能提供了一种科学方法。Composites Part A: Applied Science and ManufacturingUltra-high strength metal matrix composites (MMCs) with extended ductility manufactured by size-controlled powder and spherical cast tungsten carbideYiqi Zhou, Li Wang, Decheng Kong, Bowei Zhang, Tingting Liu, Yu Yan, Li Zhang, Xiaogang Li, Dirk Engelberg, Chaofang Dongdoi:10.1016/j.compositesa.2024.108194通过尺寸控制粉末和球形铸造碳化钨制造具有扩展延展性的超高强度金属基复合材料(MMCThe main challenge of particle-reinforced metal matrix composites (MMCs) is balancing strength and ductility. This research uses type 420 stainless steel and spherical cast tungsten carbide (WC/W2C) with a similar powder size and range as raw powders to manufacture laser powder bed fusion (LPBF) 420 + 5 wt% WC/W2C MMCs. LPBF 420 + 5 wt% WC/W2C MMCs contain austenite, martensitic, and W-rich carbides (WC/W2C, FeW3C, M6C, and M7C3) from nanometre to micrometre scale. The well-balanced composition creates a crack-free reaction layer between reinforced particles and the matrix. This reaction layer consists of two distinct layers, depending on the element composition. The LPBF 420 + 5 wt% WC/W2C MMCs achieved an excellent compressive strength of ∼5.5 GPa and a considerable fracture strain exceeding 50 %. The underlying mechanisms for the improved mechanical properties are discussed, providing further insight to advance the application of MMCs via additive manufacturing.颗粒增强金属基复合材料(MMC)的主要挑战是平衡强度和延展性。本研究使用粉末尺寸和范围相似的 420 型不锈钢和球形铸造碳化钨(WC/W2C)作为原料粉,制造激光粉末床熔融(LPBF)420 + 5 wt% WC/W2C MMC。LPBF 420 + 5 wt% WC/W2C MMC 包含奥氏体、马氏体和富含 W 的碳化物(WC/W2C、FeW3C、M6C 和 M7C3),从纳米级到微米级。均衡的成分在增强颗粒和基体之间形成了无裂纹反应层。根据元素成分的不同,反应层由两个不同的层组成。LPBF 420 + 5 wt% WC/W2C MMC 的抗压强度达到 5.5 GPa,断裂应变超过 50%。本文讨论了提高机械性能的基本机制,为通过增材制造推进 MMC 的应用提供了进一步的见解。Composites Part B: EngineeringEnalaprilat-loaded polyphenol nanoparticle composite hydrogel promotes myocardial protection after acute infarctionZhiyu Zhao, Hong Xu, Annuo Li, Hongxia Pu, Peiyi She, Gaocan Li, Yunbing Wangdoi:10.1016/j.compositesb.2024.111430依那普利拉负载多酚纳米粒子复合水凝胶促进急性心肌梗死后的心肌保护Heart failure (HF) has been increasing in morbidity and mortality worldwide, and one of the important causes of heart failure is myocardial infarction (MI), in which the coronary arteries are unable to provide sufficient blood flow to myocardial tissues, leading to necrosis and apoptosis, activation of inflammatory responses and neuroendocrine systems such as renin-angiotensin-aldosterone system (RAAS), generation of adverse ventricular remodeling, and finally the development of heart failure. In this paper, a drug-loaded polyphenol nanoparticles (ESaB NPs) containing active Angiotensin-converting enzyme inhibitor (ACEI) drugs enalaprilat and salvianolic acid B have been designed for the pathologic characteristics of acute MI. On this basis, a collagen/fucoidan hydrogel with good bioactivity and mechanical properties has been prepared, and the nanoparticles are incorporated into the aforementioned hydrogel to obtain a composite hydrogel (Gel-ESaB) with multiple synergistic therapeutic functions. The introduction of fucoidan can not only improve the mechanical strength and injectability of the collagen-based hydrogel, but also confer the collagen material with anticoagulant properties that are essential for future clinical applications as cardiovascular biomaterials. While providing mechanical support to the infarct site, the ESaB NPs delivered in situ to the infarct site play a key role in protecting myocardial tissue and restoring cardiac function through ROS scavenging, inflammation alleviation and tissue RAAS inhibitory ability. Both in vitro and in vivo experiments have confirmed the excellent therapeutic ability of Gel-ESaB in the treatment of MI and the prevention of HF after MI, which is expected to be an effective approach for MI treatment.心力衰竭(HF)在全球的发病率和死亡率不断上升,而心力衰竭的重要原因之一是心肌梗死(MI),心肌梗死时冠状动脉无法为心肌组织提供足够的血流,导致心肌组织坏死和凋亡,激活炎症反应和神经内分泌系统,如肾素-血管紧张素-醛固酮系统(RAAS),产生不良的心室重构,最终发展为心力衰竭。本文针对急性心肌梗死的病理特征,设计了一种含有活性血管紧张素转换酶抑制剂(ACEI)药物依那普利拉和丹酚酸 B 的药物负载多酚纳米颗粒(ESaB NPs)。在此基础上,制备了具有良好生物活性和机械性能的胶原蛋白/褐藻糖胶水凝胶,并将纳米颗粒融入上述水凝胶中,得到了具有多种协同治疗功能的复合水凝胶(Gel-ESaB)。褐藻糖胶的引入不仅能提高胶原蛋白水凝胶的机械强度和可注射性,还能赋予胶原蛋白材料抗凝特性,这对未来作为心血管生物材料的临床应用至关重要。ESaB NPs 在为心肌梗塞部位提供机械支撑的同时,通过清除 ROS、缓解炎症和抑制组织 RAAS 的能力,在保护心肌组织和恢复心脏功能方面发挥了关键作用。体外和体内实验均证实了 Gel-ESaB 在治疗心肌梗死和预防心肌梗死后高房颤动方面的卓越治疗能力,有望成为治疗心肌梗死的有效方法。Composites Science and TechnologyBacterial cellulose-based composite films with liquid metal/graphene synergistic conductive pathways for superior electromagnetic interference shielding and Joule heating performanceYuanhang Ge, Lequan Wang, Bo Hu, Hongbin Lu, Yizhen Shaodoi:10.1016/j.compscitech.2024.110582 具有液态金属/石墨烯协同导电途径的细菌纤维素基复合薄膜,可实现卓越的电磁干扰屏蔽和焦耳加热性能Modern integrated electronics are in great demand for high-performance electromagnetic interference (EMI) shielding materials with exceptional mechanical properties. Liquid metal (LM) has demonstrated great potential in EMI shielding by its superior electrical conductivity. However, its real-world EMI application is limited by the poor compatibility, insulating oxide shells, and unpredictable leakage. Here, graphene oxide (GO) is used to encapsulate LM to form LM@GO microdroplets dispersion, and bacterial cellulose (BC) is applied to construct a biocompatible fabric network. Moreover, GO is in-situ reduced by hydrazine vapor, which generates synergistic LM/reduced graphene oxide (rGO) conductive pathways with the aid of roll-in process, obtaining flexible LM/rGO/BC (LGB) composite film with outstanding electrical conductivity of 4.5 × 104 S/m and exceptional shielding effectiveness of 64.0 dB. The rGO sheets and BC network demonstrate layered structure after roll-in process, effectively impeding the leakage and oxidation of LM and achieving a tensile strength up to 62.9 MPa of LGB films. Meanwhile, the LGB films exhibit exceptional Joule heating performance, and the stable surface temperature reaches 110 °C with high stability and reliability when the applied voltage is 4 V. This work provides a feasible engineering approach to prepare LM-based films for applications in EMI shielding and wearable electronics.现代集成电子设备对具有优异机械性能的高性能电磁干扰(EMI)屏蔽材料的需求量很大。液态金属 (LM) 凭借其卓越的导电性,在 EMI 屏蔽方面展现出巨大的潜力。然而,由于兼容性差、绝缘氧化物外壳和不可预测的泄漏,液态金属在 EMI 领域的实际应用受到了限制。在这里,氧化石墨烯(GO)被用来封装 LM,形成 LM@GO 微滴分散体,细菌纤维素(BC)被用来构建生物相容性织物网络。此外,GO 被肼蒸气原位还原,借助卷入工艺产生协同的 LM/ 还原氧化石墨烯(rGO)导电通路,从而获得柔性 LM/rGO/BC (LGB) 复合薄膜,其导电率高达 4.5 × 104 S/m,屏蔽效果高达 64.0 dB。卷入工艺后,rGO 片材和 BC 网络呈现分层结构,有效阻止了 LM 的泄漏和氧化,使 LGB 薄膜的拉伸强度达到 62.9 兆帕。同时,LGB 薄膜表现出优异的焦耳加热性能,在施加 4 V 电压时,其表面温度稳定在 110 ℃,具有很高的稳定性和可靠性。这项工作为制备基于 LM 的薄膜提供了一种可行的工程方法,可应用于 EMI 屏蔽和可穿戴电子设备。Self-catalysed frontal polymerisation enables fast and low-energy processing of fibre reinforced polymer compositesJeroen Staal, Baris Caglar, Véronique Michauddoi:10.1016/j.compscitech.2024.110584 自催化正面聚合可实现纤维增强聚合物复合材料的快速、低能耗加工Frontal polymerisation has the potential to bring unprecedented reductions in energy demand and process time to produce fibre reinforced polymer composites. Production of epoxy-based fibre reinforced polymer parts with high fibre volume content, commonly encountered in industry, is however hindered by the heat sink created by the fibres and the mould, overcoming the heat output of the chemical reaction, thus preventing front propagation. We propose a novel self-catalysed frontal polymerisation manufacturing method based on the integration of thin resin channels in thermal contact with the composite stack as a strategy for low-energy production of high fibre volume fraction polymer composites without the need for a continuous energy input. Frontal polymerisation inside the resin channel proceeds faster and preheats the fabric stack, thus catalysing the process. Parts with up to 60% fibre content are successfully produced independently of the sample thickness. Fillers added within the resin channels provide means to tailor the frontal polymerisation process kinetics. The parts have a significantly higher glass transition temperature than those produced in a conventional oven, and comparable mechanical properties while energy consumption is reduced by over 99.5%.在生产纤维增强聚合物复合材料的过程中,正面聚合有可能带来前所未有的能源需求和工艺时间的减少。然而,由于纤维和模具所产生的散热片超过了化学反应所产生的热量,从而阻碍了正面聚合的进行。我们提出了一种新型自催化正面聚合制造方法,该方法基于与复合材料堆栈热接触的薄树脂通道的整合,是一种无需持续输入能量即可低能耗生产高纤维体积分数聚合物复合材料的策略。树脂通道内的正面聚合反应进行得更快,并预热织物堆栈,从而催化这一过程。可成功生产出纤维含量高达 60% 的部件,而不受样品厚度的影响。在树脂通道内添加填料可以调整正面聚合过程的动力学。这些部件的玻璃化温度明显高于传统烘箱生产的部件,机械性能也不相上下,而能耗却降低了 99.5% 以上。来源:复合材料力学仿真Composites FEM

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