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【新文速递】2024年4月25日固体力学SCI期刊最新文章

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今日更新:Journal of the Mechanics and Physics of Solids 1 篇,Thin-Walled Structures 1 篇

Journal of the Mechanics and Physics of Solids

Robust implementation of Physical Regime Sensitivity and demonstration on Richtmyer-Meshkov instability experiments

Joshua W. Dyer, Jiajia Waters, Michael B. Prime

doi:10.1016/j.jmps.2024.105656

物理状态敏感性的鲁棒实现及richmyer - meshkov不稳定性实验的验证

We present a robust analytic implementation of Physical Regime Sensitivity (PRS), which quantifies sensitivity of an experiment or application to regimes of a material model’s independent variables rather than to model parameters. The new PRS implementation is tested on impact-driven Richtmyer-Meshkov Instability (RMI) strength experiments on tantalum. Sequential PRS hydrocode simulations perturbed strength in local regimes of independent variables like strain rate to quantify the resulting effects on experimentally measured maximum spike velocities in the instabilities. The numeric behavior of the sensitivity calculation is investigated regarding mesh convergence and the parameters controlling the strength perturbation. The sensitivities generally converge with mesh size at least as quickly as the underlying RMI simulations. A wide range of perturbation amplitudes produced similar normalized sensitivities, indicating the perturbation is not changing physical behavior in the simulation. Adjusting the range (width) over which the strength is perturbed allows for resolving fine sensitivity features covering narrow regimes of independent variables or more broad regimes for general interpretation. For interpreting RMI, PRS shows that the maximum spike velocity of the instability is most sensitive to a narrow regime of strain rates near 10^7/s, which occurs inside the spike as strength effects arrest the instability. The PRS analyses revealed that a modification to the experimental metric used to assess strength would better isolate the strength effects in the regimes of most interest. Using the new metric to generate pressure PRS curves revealed that sensitivities to strength at near-zero pressure were 3.5 times greater than at the high-pressure shock state, supporting the practice of using RMI to isolate strain rate effects when combined with high-pressure experiments. It is also shown that a simple, calibrated constant strength model can reproduce PRS sensitivities of a complex, multivariate Preston-Tonks-Wallace strength model quite well, which supports the robustness of PRS and its utility for experimental design and interpretation prior to the availability of a sophisticated material strength model.

我们介绍了物理机理灵敏度(PRS)的稳健分析实现,它量化了实验或应用对材料模型自变量机理的灵敏度,而不是对模型参数的灵敏度。新的 PRS 实现方法在钽的冲击驱动里氏-麦斯科夫不稳定性(RMI)强度实验中进行了测试。连续的 PRS 水文编码模拟扰动了独立变量(如应变率)的局部强度,以量化对实验测量的不稳定性最大尖峰速度的影响。在网格收敛和控制强度扰动的参数方面,对灵敏度计算的数值行为进行了研究。灵敏度一般随网格大小收敛,收敛速度至少与基础 RMI 模拟一样快。大范围的扰动振幅产生了相似的归一化灵敏度,表明扰动并没有改变模拟中的物理行为。通过调整扰动强度的范围(宽度),可以分辨出涵盖自变量狭窄区域的精细灵敏度特征,或用于一般解释的更宽泛的区域。在解释 RMI 时,PRS 显示不稳定性的最大尖峰速度对应变率接近 10^7/s 的狭窄区域最为敏感,这发生在尖峰内部,因为强度效应会抑制不稳定性。PRS 分析表明,对用于评估强度的实验指标进行修改,可以更好地将强度效应隔离在最感兴趣的范围之外。使用新指标生成压力 PRS 曲线显示,近零压力下对强度的敏感性是高压冲击状态下的 3.5 倍,这支持了在结合高压实验时使用 RMI 隔离应变率效应的做法。实验还表明,一个简单的校准恒定强度模型可以很好地再现复杂的多变量普雷斯顿-顿克斯-华莱士强度模型的 PRS 敏感性,这支持了 PRS 的稳健性及其在复杂的材料强度模型可用之前对实验设计和解释的实用性。


Thin-Walled Structures

Probe maps for the exploration of localized metastable states and prediction of peak load-carrying capacity of axially compressed cylindrical shells

Suhas Ankalkhope, Sandeep Jose, Sujith Thomas

doi:10.1016/j.tws.2024.111934

轴向压缩圆柱壳的局部亚稳态探测图和峰值承载能力预测

A Machine Learning (ML) based analysis is conducted to find the most influential probing parameter in determining the buckling initiation location by assessing Probe Force – Probe Displacement characteristic curves. This is followed by the construction of Probe maps, which systematically depict the variation of this parameter with the help of numerical simulations incorporating Measured Geometric Imperfections (MGI). The probe maps hence constructed are found to be effective in identifying the critical locations where a single dimple is likely to initiate the buckling, enabling the complete exploration of the critical single dimple states of the structure. The experiments by probing the structure at the critical locations identified using probe maps show accurate prediction of the peak load-carrying capacity. The approach presented in the study may be extrapolated to characterize imperfection-sensitive structures in general.

通过评估探针力-探针位移特征曲线,进行基于机器学习的分析,寻找对确定屈曲起始位置影响最大的探针参数。接下来是探针图的构建,它系统地描述了该参数的变化,借助于包含测量几何缺陷(MGI)的数值模拟。由此构建的探针图被发现可以有效地识别单个韧窝可能引发屈曲的关键位置,从而能够完整地探索结构的关键单韧窝状态。利用探测图在关键位置对结构进行探测,可以准确预测结构的峰值承载能力。研究中提出的方法可以外推到一般不完美敏感结构的特征。



来源:复合材料力学仿真Composites FEM
ACTFluentSystemCONVERGEUM材料控制
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首次发布时间:2024-11-14
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【新文速递】2024年4月27日复合材料SCI期刊最新文章

今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 2 篇Composite StructuresDeformation behavior and scale effects in microchannel hydroforming in ultra-thin TA1/CFRP fuel cell bipolar platesYao Wang, Jiachen Cui, Yong Li, Yanfeng Zhang, Sifa Zheng, Libin Zhao, Ning Hudoi:10.1016/j.compstruct.2024.118164超薄TA1/CFRP燃料电池双极板微通道液压成形的变形行为和尺度效应Microchannels of fuel cell bipolar plates have complex shapes and dimensions at the microscale level, posing significant challenges for manufacturing. Additionally, for traditional bipolar plate materials, mainly based on graphite composites and metals, make it difficult to meet the increasing performance requirements. As the latest fourth-generation fiber-reinforced metal composites, Ti/CFRP laminates exhibit high impact resistance and stiffness after solidification and are electrically conductive, presenting broad prospects for application in bipolar plates. In this study, the metallic layer of the traditional Ti /CFRP laminate was miniaturized to microscale, and a new method for ultra-thin TA1/CFRP laminate low-constraint hydro-microforming was proposed. By combining theoretical modeling, numerical simulation, and process experiments, the deformation behavior and scale effects of the laminate, during the microchannel hydroforming process, were investigated under different process and structural parameters. A single-channel deformation mode was used to study the forming process and examine the impact of hydraulic pressure loading paths and temperature. Additionally, multi-channel and curved channel deformation modes were employed to elucidate the influence of section inclination, channel width, ridge width, and bending angle on the forming process. By varying the laminate thickness, grain size and friction status, the geometric, grain and friction scale effects, as well as the microscale mechanisms of ultra-thin TA1/CFRP laminates in microchannel forming, were explored. This study explores new avenues for the precise microforming of lightweight laminate structures and their application in fuel cell bipolar plates. It provides a theoretical foundation to address the challenges in the microchannel forming of laminates and improve forming accuracy and performance quality.燃料电池双极板的微通道在微尺度上具有复杂的形状和尺寸,给制造带来了巨大的挑战。此外,传统的双极板材料主要以石墨复合材料和金属为主,难以满足日益提高的性能要求。Ti/CFRP层压板作为最新的第四代纤维增强金属复合材料,凝固后具有较高的抗冲击性和刚度,并具有导电性,在双极板上具有广阔的应用前景。本研究将传统Ti /CFRP层压板金属层微型化至微尺度,提出了一种超薄TA1/CFRP层压板低约束水力微成形新方法。通过理论建模、数值模拟和工艺实验相结合的方法,研究了不同工艺参数和结构参数下层压板在微通道液压成形过程中的变形行为和尺度效应。采用单通道变形模式研究了成形过程,并考察了液压加载路径和温度对成形过程的影响。此外,采用多通道和弯曲通道两种变形模式,分析了截面倾角、通道宽度、脊宽和弯曲角度对成形过程的影响。通过改变层合材料厚度、晶粒尺寸和摩擦状态,探讨了TA1/CFRP超薄层合材料在微通道形成过程中的几何效应、晶粒效应和摩擦尺度效应,以及微观尺度机制。本研究为轻质层压板结构的精确微成形及其在燃料电池双极板中的应用开辟了新的途径。为解决层压板微通道成形难题,提高成形精度和性能质量提供了理论基础。Silkworm cocoon-inspired and robust nanofibrous composite separator with gradient structure for lithium ion batteriesJiayi Li, Lu Lu, Haibo Liang, Yan Sun, Xuesong Guo, Zhenzhen Wei, Yan Zhaodoi:10.1016/j.compstruct.2024.118161 基于蚕茧的纳米纤维复合材料梯度结构锂离子电池分离器Considering electrospun nanofiber-based membranes that generally exhibit high porosity but poor mechanical property, there is a growing need to fabricate nanofibrous separators with comprehensive performance for lithium-ion batteries (LIBs). Silkworm cocoon, a source of design inspiration from nature, comprises a multilayer structure with composition change in the thickness direction, thereby endowing the cocoon with relatively high porosity and outstanding mechanical strength. Therefore, a silkworm cocoon-like structured nanofibrous separator (GPS) is fabricated in this work by initially preparing several polyacrylonitrile (PAN) nanofibrous membranes with varied content of carboxyl styrene butadiene latex (SBR) and then laminating them in a concentration gradient sequence. Compared with the pristine PAN membrane, the GPS exhibits comparable porosity, thermal stability and electrolyte wettability due to the existence of PAN nanofibers, while the tensile strength and puncture resistance of the GPS are greatly raised by 5.5 times and 1.5 times, respectively. On account of the structure design, GPS also shows better mechanical strength than PAN/SBR separators without concentration gradient, and the strengthening mechanism has been verified by the finite element analysis. Meanwhile, such gradient structure of GPS renders the battery with desirable ion transport ability and stable cycle properties. Thus, the silkworm cocoon-like structured separator could be a promising separator candidate for LIBs, and the bioinspired design in structure will play an increasingly important role in the development of high-performance battery in the future.考虑到电纺丝纳米纤维基膜孔隙率高但力学性能差的特点,制备具有综合性能的锂离子电池纳米纤维隔膜的需求日益增长。蚕茧的设计灵感来源于大自然,蚕茧由多层结构组成,其成分在厚度方向上发生变化,从而使蚕茧具有较高的孔隙率和突出的机械强度。因此,本研究首先制备了几种含有不同含量的羧基丁二烯乳胶(SBR)的聚丙烯腈(PAN)纳米纤维膜,然后按浓度梯度顺序层合,制备了蚕茧状结构纳米纤维分离器(GPS)。与原始PAN膜相比,由于PAN纳米纤维的存在,GPS具有相当的孔隙度、热稳定性和电解质润湿性,而GPS的抗拉强度和抗穿刺能力分别提高了5.5倍和1.5倍。由于结构设计的原因,GPS比无浓度梯度的PAN/SBR分离器具有更好的机械强度,并通过有限元分析验证了其强化机理。同时,GPS的这种梯度结构使电池具有良好的离子输运能力和稳定的循环性能。因此,蚕茧状结构隔膜可能是一种很有前途的锂离子电池隔膜候选材料,而结构上的仿生设计将在未来高性能电池的发展中发挥越来越重要的作用。Composites Part A: Applied Science and ManufacturingTemperature dependence of optical properties for thermoplastic composite prepreg during laser in-situ consolidationZehui Wang, Jinrui Ye, Kai Liu, Xiaodong Wang, Yingjie Qiaodoi:10.1016/j.compositesa.2024.108235 激光原位固结过程中热塑性复合材料光学性能的温度依赖性The optical properties of the thermoplastic prepreg play a critical role in influencing heating efficiency during the in-situ consolidation process. This study investigates the temperature-dependent reflectance of the prepreg during laser heating. A reflectance testing device is developed based on an in-situ heating system, and the reflectance of carbon fiber/PEEK prepreg is studied from 20 to 500 °C. Through a comparative analysis, the reflectance of pure PEEK films and carbon fibers are individually examined within the same temperature range. The variation in reflectance at different temperatures is explained according to the classical electromagnetic theory. Furthermore, the effect of fiber density on the reflectance of thermoplastic prepreg is explored, and the results indicate that the reflectance of the prepreg decreases from 15.65 % to 11.80 % as the temperature rises from 20 °C to 500 °C, which can be primarily attributed to the decline in carbon fiber reflectance with increasing temperature.在原位固结过程中,热塑性预浸料的光学性能对热效率的影响至关重要。研究了激光加热过程中预浸料的反射率随温度的变化规律。研制了一种基于原位加热系统的反射率测试装置,研究了碳纤维/PEEK预浸料在20 ~ 500 °C范围内的反射率。通过对比分析,分别考察了纯PEEK薄膜和碳纤维在相同温度范围内的反射率。根据经典电磁理论解释了不同温度下反射率的变化。研究了纤维密度对热塑性预浸料反射率的影响,结果表明:当温度从20 °C升高到500 °C时,预浸料反射率从15.65 %降低到11.80 %,这主要是由于温度升高导致碳纤维反射率下降。Natural coal-derived graphite as rubber filler and the influence of its progressive graphitization on reinforcement performanceHao Zhang, Yongjie Yang, Qinfu Liu, Leibo Ji, Zhiming Sun, Junmin Sun, Zhijing Han, Qianyi Ma, Hua Yang, Yubin Ke, Chul B. Park, Naisheng Jiangdoi:10.1016/j.compositesa.2024.108237 天然煤基石墨作为橡胶填料及其逐步石墨化对增强性能的影响This study introduces a reinforcing rubber filler, natural coal-derived graphite (NCDG), evaluating how its progressive structural evolution from meta-anthracite (MA), semi-graphite (SG) to cryptocrystalline graphite (CG) during the natural graphitization process affects their reinforcing performance to styrene-butadiene rubber (SBR) composites. The highly graphitized NCDG fillers exhibit good filler dispersion, more bound rubber content, and well compatibility between filler and rubber matrix when compounded with SBR, and significantly enhance the mechanical properties of SBR composite (tensile strength can reach 22.8 MPa), as well as improving the storage modulus, wet-skid resistance, wear resistance, and electrical conductivity. The formation of microcrystalline multilayer graphene and graphene nanoplatelets exfoliated by mechanical shear stress during ball grinding and rubber compound mixing plays an important role in improving the reinforcement performance of rubber composites. This research provides valuable insights into the utilization of NCDG as a cost-effective and environment-friendly reinforcing filler for rubber composites.本研究介绍了一种增强橡胶填料——天然煤衍生石墨(NCDG),评估了其在自然石墨化过程中从间无烟煤(MA)、半石墨(SG)到隐晶石墨(CG)的渐进结构演变对其增强丁苯橡胶(SBR)复合材料性能的影响。高石墨化NCDG填料与SBR复合后,填料分散性好,粘结胶含量高,填料与橡胶基体相容性好,显著提高了SBR复合材料的力学性能(抗拉强度可达22.8 MPa),提高了SBR复合材料的储存模量、抗湿滑性、耐磨性和导电性。在球磨和胶料混炼过程中,受机械剪切应力剥落形成微晶多层石墨烯和石墨烯纳米片,对提高橡胶复合材料的增强性能具有重要作用。本研究为利用NCDG作为一种经济、环保的橡胶复合材料增强填料提供了有价值的见解。Composites Part B: EngineeringDeveloping a binary composite of covalent organic framework and gold microstructures: Highly efficient dual-mode catalyst for analysis of nitrophenol isomers and their oxidative productsPonnusamy Arul, Sheng-Tung Huang, Chinnathambi Nandhini, Chi-Hsien Huang, N.S.K. Gowthamandoi:10.1016/j.compositesb.2024.111493 开发一种共价有机骨架与金微结构二元复合材料:分析硝基苯酚异构体及其氧化产物的高效双模催化剂As a key hazard, nitrophenol and its byproducts are a vital raw material in the industry and potentially released into aquatic environments, which affects the ecosystem and severely threatens living systems. It is crucial to detect nitro-hazards quantitatively and systematically. The unique structures of isomer separation and catalytic reduction are highly complex in a single system, not yet reported detection method. The present report constructed robust gold-microstructures (AuMSs) with bis-triazole-derived covalent organic framework (BTCOF) was developed to analyze the dual-mode application of electrochemical redox signals and catalytic degradation of nitrophenol isomers (NPIs) and their oxidative products. The synergistic interaction of tunable surfaces on binary materials enhanced catalytic efficiency, faster kinetic rates, and poor passivation. Based on the variance in pKa values, both NPIs and nitrosophenols (NSPIs) could be identified, peak separated, and sensed simultaneously. A catalyst combined with NaBH4, enabled NPIs reduction within ten minutes. This proposed electrochemical method achieved a nanomolar LOD (1.82, 1.67, and 1.15 × 10-9 M for o-, m-, and p-NPs), excellent sensitivity to ultrawide linear concentrations while being selective, and reproducible. Moreover, AuMSs-BTCOF/GCE detected NPIs in the industrial effluents and biofluids samples with recovery rates between 94.70-99.95 ± 0.18% with RSD < 3%. The electrochemical result was validated by conventional method with proven statistical analysis (error < 4.0%). In the catalytic reduction of NPIs, the catalyst is more than 89.24% efficient, and durable stability. The designed system has proven to be an effective, sensitive, and accurate dual-detection tool for monitoring environmental targets and diagnosing diseases.硝基酚及其副产物作为一种关键危害物质,是工业中重要的原料,并可能释放到水生环境中,影响生态系统,严重威胁生命系统。定量、系统地检测硝基危害至关重要。异构体分离和催化还原的独特结构在单一体系中高度复杂,尚未有报道的检测方法。本文利用双三 唑衍生共价有机骨架(BTCOF)构建了稳健的金微结构(AuMSs),分析了电化学氧化还原信号的双模式应用和硝基酚异构体(NPIs)及其氧化产物的催化降解。可调表面在二元材料上的协同作用提高了催化效率、更快的动力学速率和较差的钝化。根据pKa值的变化,npi和亚硝基酚(NSPIs)可以同时被识别、分离峰和检测。与NaBH4结合的催化剂可以在10分钟内还原npi。该电化学方法获得了纳米摩尔的LOD (o-、M -和p- np分别为1.82、1.67和1.15 × 10-9 M),对超宽线性浓度具有良好的灵敏度,同时具有选择性和可重复性。此外,AuMSs-BTCOF/GCE在工业废水和生物流体样品中检测npi,回收率为94.70 ~ 99.95±0.18%,RSD < 3%。电化学分析结果与常规方法一致,误差< 4.0%。在npi的催化还原中,催化剂效率达89.24%以上,且持久稳定。该系统已被证明是一种有效、灵敏、准确的环境目标监测和疾病诊断双重检测工具。STRENGTHENING SANDWICH COMPOSITES BY LAMINATING ULTRA-THIN ORIENTED CARBON NANOTUBE SHEETS AT THE SKIN/CORE INTERFACEDongyang Cao, Tingge Xu, Mengmeng Zhang, Zhong Wang, D. Todd Griffith, Samit Roy, Ray H. Baughman, Hongbing Ludoi:10.1016/j.compositesb.2024.111496超薄定向碳纳米管片在皮芯界面强化夹层复合材料Strong, tough, and lightweight composites are increasingly needed for diverse applications, from wind turbines to cars and aircraft. These composites typically contain sheets of strong and high-modulus fibers in a matrix that are joined with other materials to resist fracture. Coupling these dissimilar materials together is challenging to enhance delamination properties at their interface. We herein investigate using a trace amount of carbon nanotube sheets to improve the coupling between composite skins and core in a composite sandwich. Ultra-thin (∼100 nm) forest-drawn multi-walled carbon nanotube (MWNT) sheets are interleaved within the skin/core interphase, with MWNTs aligned in the longitudinal direction. The mechanical behavior is characterized by end-notched flexural testing (ENF). With two MWNT sheets placed in the skin/core interphase, the following performance enhancements are achieved: 36.8% increase in flexural strength; 127.3% and 125.7% increases in mode I & II fracture toughness values, respectively; and 152.8% increase in interfacial shear strength (IFSS). These are achieved with negligible weight gain of the composite sandwich (0.084 wt% increase over the baseline sandwich without MWNT sheets). The finite element simulation results show that MWNT sheets enhance the skin/core coupling by reducing stress concentration, enabling the transition from catastrophic brittle failure to a stable ductile failure mode. The MWNT sheets interleaved sandwich composites are thus demonstrated to be stronger and tougher while providing electrical conductivity (4.3×10^4) at the skin/core interface for potential de-icing, electromagnetic interference shielding, and structural health monitoring.从风力涡轮机到汽车和飞机,越来越多的应用需要坚固、坚韧和轻质的复合材料。这些复合材料通常在基体中含有高强度和高模量的纤维片,与其他材料结合以抵抗断裂。将这些不同的材料耦合在一起,以增强其界面的分层性能是具有挑战性的。在此,我们研究了在复合材料夹层中使用微量碳纳米管片来改善复合材料外壳和核心之间的耦合。超薄(~ 100 nm)森林绘制的多壁碳纳米管(MWNT)片在皮/核间期内交错,MWNT在纵向上排列。通过端缺口弯曲试验(ENF)对其力学性能进行表征。将两片MWNT片置于表皮/芯间,可实现以下性能增强:抗弯强度提高36.8%;ⅰ型和ⅱ型断裂韧性值分别提高127.3%和125.7%;界面抗剪强度(IFSS)提高152.8%。复合材料夹层的重量增加可以忽略不计(比没有MWNT片材的基线夹层增加0.084 wt%)。有限元模拟结果表明,MWNT板通过降低应力集中,增强了皮芯耦合,使其从灾难性脆性破坏过渡到稳定的延性破坏模式。因此,MWNT片交错夹层复合材料被证明在提供电导率(4.3×10^4)的同时更强、更坚韧,用于潜在的除冰、电磁干扰屏蔽和结构健康监测。Enhanced antibacterial activity of polyphenol-bound microtopography by synergistic chemical and micro/nanomechanical effectsPei Liu, Yuzheng Wu, Kaiwei Tang, Babak Mehrjou, Jin Tao, Guomin Wang, Huaiyu Wang, Zhengwei Wu, Paul K. Chudoi:10.1016/j.compositesb.2024.111498多酚结合微形貌通过协同化学和微/纳米力学效应增强抗菌活性Initial microbial attachment on surfaces is the first step in bacteria contamination and direct intervention in the early adhesion stage by constructing an antibacterial coating is an effective strategy to prevent the attachment and proliferation of bacteria. Herein, a storable polyphenol-based coating is designed and fabricated by self-assembling the cationic template and ionic ligand. The materials containing microparticles with sticky properties inherited from tannic can be deposited on various surfaces by a simple redispersion-immersion process. The functional ligands on the outer layer of the coating can kill bacteria by combining chemical damages produced by tannic as well as mechanical disruption caused by the micro-nano topography as reflected by the elevated Young’s modulus and differentiated stiffness of the bacterial membrane. The results reveal a simple method to prepare polyphenol-based antibacterial coatings and enrich our understanding of the combined use of chemical and mechanical interventions to enhance the antibacterial activity.微生物在表面的初始附着是细菌污染的第一步,通过构建抗菌涂层直接干预粘附的早期阶段是防止细菌附着和增殖的有效策略。本文通过阳离子模板和离子配体的自组装,设计并制备了一种可储存的多酚基涂层。通过简单的再分散-浸渍工艺,可以在各种表面上沉积具有从单宁继承的粘性微粒的材料。涂层外层的功能配体可以通过单宁产生的化学损伤和微纳形貌引起的机械破坏来杀死细菌,这反映在细菌膜的杨氏模量升高和刚度分化上。该结果为制备多酚类抗菌涂料提供了一种简单的方法,丰富了我们对化学和机械联合干预提高抗菌活性的认识。Composites Science and TechnologyOne-dimensional KNN micro rods doping to facilitate the energy conversion performance of a KNN MRs/P(VDF-TrFE) compositeXiaofang Zhang, Weimin Xia, Jing Li, Xusheng Wang, Chengmin Hou, Zhicheng Zhangdoi:10.1016/j.compscitech.2024.110626 一维KNN微棒掺杂提高KNN MRs/P(VDF-TrFE)复合材料的能量转换性能Piezoelectric self-powered electronic devices can convert ambient mechanical vibrations into electrical energy in an environmentally friendly manner, significantly alleviating the scarcity of non-renewable sources. This work prepares an one-dimensional potassium sodium niobate micro rods (1D KNN MRs) using the molten salt - topological chemical reaction method, showing the significant advantages over 0-dimension (0D) nanoparticles due to its anisotropy. Simultaneously, KNN MRs are introduced into poly(vinylidene fluoride-trifluoroethylene) to form a KNN MRs/P(VDF-TrFE) piezoelectric composite, effectively facilitating the piezoelectric β-phase in P(VDF-TrFE) film, and contributing to a high remnant polarization (Pr ∼12.3 μC/cm2) at 125 MV/m and a high piezoelectric constant (d33=-28 pC/N). Interestingly, a piezoelectric sensor assembled by KNN MRs/P(VDF-TrFE) composite shows a considerable piezoelectric output of 17.6 V at a scene of 2.5 MPa stress, offering a novel route for designing the optimum ceramic/polymer combinations suitable for mechanical energy conversion and energy harvesting.压电自供电电子设备能以环境友好的方式将周围的机械振动转化为电能,大大缓解了不可再生资源匮乏的问题。本研究采用熔盐-拓扑化学反应法制备了一维铌酸钠钾微棒(1D KNN MRs),由于其各向异性,与 0 维(0D)纳米粒子相比具有显著优势。同时,KNN MRs 被引入聚偏氟乙烯-三氟乙烯(poly(Vinylidene fluoride-trifluoroethylene))中,形成 KNN MRs/P(VDF-TrFE) 压电复合材料,有效促进了 P(VDF-TrFE) 薄膜中的压电 β 相,并在 125 MV/m 时产生高残余极化(Pr ∼12.3 μC/cm2)和高压电常数(d33=-28 pC/N)。有趣的是,由 KNN MRs/P(VDF-TrFE) 复合材料组装的压电传感器在 2.5 兆帕应力下显示出 17.6 伏的可观压电输出,为设计适用于机械能转换和能量收集的最佳陶瓷/聚合物组合提供了一条新途径。In situ Three-roll Mill Exfoliation Approach for Fabricating Asphalt/Graphite Nanoplatelet Composites as Thermal Interface MaterialsYingfeng Wen, Chao Chen, Hongru Zhou, Xiaojing Li, Xuyang Wang, Xingping Zhou, Xiaolin Xie, Yiu-Wing Maidoi:10.1016/j.compscitech.2024.110627 制备沥青/石墨纳米板复合材料作为热界面材料的原位三辊磨剥落法Thermal interface materials (TIMs) are vital to dissipate excess heat generated by electronic components with ever-growing power density to ensure their reliability and performance. However, the limited dispersibility of nano-sized thermal conductive fillers hinders further enhancement of thermal conductivity in TIMs. It remains challenging to manufacture high-performance TIMs with simultaneous high thermal conductivity, low cost, and capability of large-scale production. Herein, a solvent-free and scalable approach was adopted to fabricate asphalt/graphite nanoplatelets (GNPs) composites by in situ exfoliating graphite in asphalt melt using a three-roll mill. During exfoliation, asphalt was adsorbed onto the surface of GNPs via π-π interaction and improved their dispersibility. Hence, GNPs formed integrated thermal conductive pathways with reduced interfacial thermal resistance, which significantly improved the thermal conductivity of asphalt/GNP composites. At 25 vol.% loading, the asphalt/GNP composite displayed a thermal conductivity of 1.95 W·m-1·K-1, showing a 114% increase compared to the asphalt/commercial GNP (c-GNP) composite prepared by conventional mechanical mixing. Moreover, the heat-resistant and mechanical properties of the asphalt/GNP composites were also enhanced due to the improved filler dispersion and filler-matrix interactions. Thus, the asphalt/GNP composites fabricated by in situ three-roll milling possessed remarkable advantages as TIMs compared with asphalt/c-GNP composites and commercial silicone rubber thermal pads.热界面材料(TIMs)对于消散功率密度不断增长的电子元件产生的多余热量,以确保其可靠性和性能至关重要。然而,纳米级导热填料的分散性有限,阻碍了TIMs导热性能的进一步提高。制造同时具有高导热性、低成本和大规模生产能力的高性能TIMs仍然是一个挑战。本文采用一种无溶剂、可扩展的方法,利用三辊磨机原位剥离沥青熔体中的石墨,制备沥青/石墨纳米片复合材料。在剥离过程中,沥青通过π-π相互作用吸附在GNPs表面,提高了GNPs的分散性。因此,GNPs形成了完整的导热路径,降低了界面热阻,显著提高了沥青/GNP复合材料的导热性。在25 vol.%的负荷下,沥青/GNP复合材料的导热系数为1.95 W·m-1·K-1,与传统机械混合制备的沥青/商用GNP (c-GNP)复合材料相比,导热系数提高了114%。此外,由于填料分散性和填料-基体相互作用的改善,沥青/GNP复合材料的耐热性和力学性能也得到了提高。因此,与沥青/c-GNP复合材料和商用硅橡胶热垫相比,原位三辊铣制得的沥青/GNP复合材料具有显著的TIMs优势。来源:复合材料力学仿真Composites FEM

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