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【新文速递】2024年7月8日复合材料SCI期刊最新文章

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今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇

Composite Structures

Analysis of laminated shells using pseudospectrals and the Reissner-Mixed Variational Theorem

S.C.F. Fernandes, J. Cuartero, A.J.M. Ferreira

doi:10.1016/j.compstruct.2024.118341

利用伪谱和赖斯纳-混合变分定理分析层叠壳体

In this paper, we combine the Carrera’s Unified Formulation CUF and a pseudospectral technique for predicting the static deformations and free vibrations behaviour of thin and thick cross-ply laminated shells. For the first time, the Reissner-Mixed Variational Theorem is used together with pseudospectrals to achieve a highly accurate technique. The accuracy and efficiency of this numerical technique for static and vibration problems are demonstrated through numerical examples.

在本文中,我们将卡雷拉统一公式 CUF 与伪谱技术相结合,用于预测薄层和厚层交叉层叠壳体的静态变形和自由振动行为。我们首次将赖斯纳混合变分定理与伪谱技术结合使用,从而实现了高精度技术。该数值技术在静态和振动问题上的准确性和效率通过数值示例得到了证明。


Tailoring band gap properties of curved hexagonal lattices with nodal cantilevers

Shuvajit Mukherjee, Marcus Maeder, Milan Cajić, Felix Kronowetter, Sondipon Adhikari, Steffen Marburg

doi:10.1016/j.compstruct.2024.118342

用节点悬臂调整曲面六边形晶格的带隙特性

Metamaterials find applications across diverse domains such as electromagnetics, elasticity, and acoustics by creating band gaps. Lattice-based metamaterials also exhibit band gaps, which have a great potential to influence engineering design in vibration and noise reduction problems. The geometry of the repetitive unit cell in the lattice plays a crucial role in diversifying the location and number of stop bands across the frequency range. One of the key hurdles is devising unit cell architectures that can effectively suppress vibrations across diverse frequency ranges. This work proposes an innovative two-dimensional hexagonal lattice with tailored band gap characteristics through curved beam members and auxiliary cantilever beams at the nodes. We have thoroughly explored the impact of various design parameters on dispersion characteristics, wave directionality through iso-frequency contours of dispersion surfaces, and the transmission loss considering finite lattice. The investigation demonstrates an improvement in band gap characteristics, indicating the generation of more band gaps across the entire frequency range and the widening of the same. This study has the potential to serve as a future benchmark in the development of lattice-based elastic/acoustic metamaterials, particularly for addressing vibration reduction challenges at user-defined frequencies.

超材料通过产生带隙在电磁学、弹性和声学等不同领域都有应用。基于晶格的超材料也表现出带隙,在影响减震降噪问题的工程设计方面具有巨大潜力。晶格中重复单元的几何形状在使整个频率范围内的阻带位置和数量多样化方面起着至关重要的作用。其中一个关键障碍是设计出能够在不同频率范围内有效抑制振动的单元格结构。这项研究提出了一种创新的二维六边形晶格,通过弯曲的梁构件和节点处的辅助悬臂梁来定制带隙特性。我们深入探讨了各种设计参数对色散特性的影响、通过色散面等频等值线得出的波方向性,以及考虑到有限晶格的传输损耗。研究结果表明,带隙特性得到了改善,表明在整个频率范围内产生了更多带隙并扩大了带隙。这项研究有望成为未来开发基于晶格的弹性/声学超材料的基准,特别是在解决用户定义频率的减振难题方面。


TRC truss – Proof of concept by experimental investigation

Dor Simon, Alva Peled, Yiska Goldfeld

doi:10.1016/j.compstruct.2024.118361

TRC 桁架--通过实验研究验证概念

The study develops textile-reinforced concrete (TRC) trusses, reinforced with 3D textiles. It is argued that, by taking advantage of textiles’ ability to conform to complex shapes and their corrosion resistance, TRC truss structures enable a substantial reduction in material and weight through efficient load transfer mechanisms. An experimental investigation explores the design methodology and manufacturing possibilities, as well as the macro-structural response and the cracking and failure mechanisms under flexural loading. Additionally, the study investigates the effects of various reinforcement layouts associated with different anchoring feasibilities and reinforcement ratios on the structural performance.It was found that TRC trusses maintain their structural performance compared to full cross-sectional rectangular TRC beams while achieving significant material savings and weight reduction (about 50 %). It was also found that effective anchoring is a dominant parameter governing structural response. Results from this study highlight the high potential of TRC trusses as a sustainable alternative for structural components.

该研究开发了用三维纺织品加固的纺织品加固混凝土(TRC)桁架。研究认为,通过利用纺织品适应复杂形状的能力及其耐腐蚀性,TRC 桁架结构可以通过有效的荷载传递机制大幅减少材料和重量。实验研究探讨了设计方法和制造可能性,以及宏观结构响应和弯曲加载下的开裂和破坏机制。此外,研究还探讨了与不同锚固可行性和加固比相关的各种加固布局对结构性能的影响。研究发现,与全截面矩形 TRC 梁相比,TRC 桁架在保持其结构性能的同时,还能显著节省材料和减轻重量(约 50%)。研究还发现,有效锚固是影响结构响应的主要参数。这项研究的结果凸显了 TRC 桁架作为可持续结构部件替代材料的巨大潜力。


Composites Part A: Applied Science and Manufacturing

Paper fiber-reinforced polypropylene composites from nonwoven preforms: A study on compression molding optimization from a manufacturing perspective

Cecile A. Grubb, David J. Keffer, Christopher D. Webb, Marton Kardos, Hendrik Mainka, David P. Harper

doi:10.1016/j.compositesa.2024.108339

无纺布预制件中的纸纤维增强聚丙烯复合材料:从制造角度优化压缩成型的研究

This work optimizes compression molding manufacturing for wet-formed nonwoven paper and polypropylene fiber mats. A central composite designed experiment investigated the effects of fiber reinforcement concentration, compression molding temperature, pressure, and time on composite laminate performance. We assess the composites’ density, panel thickness, water uptake, flexural behavior, and Izod impact strength. Models predicted and optimized composite performance using objective function analysis with penalties applied for undesirable conditions, such as processing time or low reinforcement concentration. Paper fiber content has the largest impact on composite properties, followed by processing time, molding pressure, and temperature. Composite optimization depends on penalty conditions; low fiber content penalties favor low fiber content panels with short processing times, while high fiber content penalties favor high fiber content panels with long processing times. This work suggests that molding composites with a greater fraction of renewable feedstock requires a commensurate increase in processing intensity.

这项研究优化了湿成型无纺纸和聚丙烯纤维毡的压缩成型制造工艺。中心复合设计实验研究了纤维增强浓度、压缩成型温度、压力和时间对复合材料层压板性能的影响。我们评估了复合材料的密度、板材厚度、吸水率、弯曲性能和伊佐德冲击强度。模型通过目标函数分析预测并优化了复合材料的性能,并对加工时间或低增强浓度等不良条件进行了惩罚。纸纤维含量对复合材料性能的影响最大,其次是加工时间、成型压力和温度。复合材料的优化取决于惩罚条件;低纤维含量惩罚有利于加工时间短的低纤维含量面板,而高纤维含量惩罚有利于加工时间长的高纤维含量面板。这项研究表明,使用更多的可再生原料模塑复合材料需要相应增加加工强度。


Fabrication of a high-temperature resistant and water-soluble sizing agent to significantly improve the interfacial properties of carbon fiber reinforced epoxy composites

Baowei Qiu, Youquan Ling, Xiwen Gu, Lei Wang, Fei Chen, Shengtai Zhou, Huawei Zou, Mei Liang

doi:10.1016/j.compositesa.2024.108344

 

制备耐高温水溶性施胶剂,显著改善碳纤维增强环氧树脂复合材料的界面性能

Applying suitable sizing agents is effective in improving the interfacial performance of carbon fiber reinforced composites (CFRPs). However, the poor thermal stability of conventional epoxy-based sizing agent limits their application at elevated temperatures for preparing advanced CFRPs. The question could lead to interfacial damage of composites at high temperatures, thus deteriorating their mechanical properties. In this work, diethanolamine (DEA) was selected to modify E51 resin to obtain a high-temperature resistant sizing agent (E51@DEA). The decomposition temperature of E51@DEA was 320 °C, which was 140 °C higher than that of E51. Furthermore, the resultant composites treated by E51@DEA 2 % showed robust interfacial performance (ILSS = 74.2 MPa, IFSS = 100.70 MPa), which was both increased by about 25 % compared to unmodified samples. In addition, the modified fiber could completely retain their interfacial reinforcement after treatment at 300 °C for 4 h. The prepared composites combined excellent thermal and interfacial properties, further expanding the application range of CFRPs.

使用合适的施胶剂可以有效改善碳纤维增强复合材料(CFRP)的界面性能。然而,传统环氧基施胶剂的热稳定性较差,限制了它们在高温下制备先进 CFRP 的应用。这一问题可能会导致复合材料在高温下发生界面破坏,从而降低其机械性能。本研究选用二乙醇胺(DEA)对 E51 树脂进行改性,从而获得一种耐高温施胶剂(E51@DEA)。E51@DEA 的分解温度为 320 ℃,比 E51 高 140 ℃。此外,经 2 % E51@DEA 处理的复合材料显示出良好的界面性能(ILSS = 74.2 MPa,IFSS = 100.70 MPa),与未改性样品相比,界面性能均提高了约 25%。此外,在 300 °C 下处理 4 小时后,改性纤维可完全保持其界面加固性能。所制备的复合材料兼具优异的热性能和界面性能,进一步扩大了 CFRP 的应用范围。


Influence of Flow-Induced crystallization and morphology on mechanical behavior in long discontinuous glass fiber polyamide composites

Siavash Sattar, Jimesh Bhagatji, Mohammad Nazmus Saquib, Diego Pedrazzoli, Mingfu Zhang, Sergey G. Kravchenko, Oleksandr G. Kravchenko

doi:10.1016/j.compositesa.2024.108353

流动诱导结晶和形态对长非连续玻璃纤维聚酰胺复合材料机械行为的影响

This study investigates the combined flow-induced crystallization in the polymer and fiber reorientation during compression molding of a long discontinuous glass fiber polyamide (PA) 6 composite. The composite is molded from an organosheet (a semi-finished pre-impregnated mat); the composite anisotropic tensile properties are evaluated as a function of polymer crystalline morphology and fiber orientation state, both controlled by the extent of material flow in the mold. To study these effects, the full mold coverage and partial center charge of organosheet (OS)-80 %, 60 %, 50 %, and 40 % were compression molded to cause varying anisotropic material flow. Tensile specimens were cut out from the molded plates in the flow and transverse direction and tested to compare their effective tensile properties (modulus and strength). The flow-induced morphological changes in a molded composite at the glass fiber bundle microstructure scale and polymer crystalline phases nano-structure were characterized using optical microscopy and X-ray diffraction, respectively. These morphological changes contributed to the significant change in the tensile strength and modulus; a combined experimental/numerical simulation framework was used to segregate the relative contribution of each factor. Experimentally, the tensile modulus increased in the flow direction from 9.6GPa to 14.9GPa for the specimens produced by full mold coverage and OS-50 % coverage mold, respectively. The tensile strength increased from 162 MPa to 254 MPa for the full and OS-60 % mold coverage. On the contrary, the strength and modulus in the transverse direction to the flow showed a significant drop to 35 MPa and 3GPa, respectively, which was attributed to reduced fiber alignment and anisotropy in the PA6 matrix.

本研究探讨了在压缩成型长间断玻璃纤维聚酰胺(PA)6 复合材料的过程中,聚合物中的流动诱导结晶和纤维重新取向的综合作用。该复合材料由有机片材(半成品预浸渍毡)模塑而成;复合材料的各向异性拉伸性能作为聚合物结晶形态和纤维取向状态的函数进行了评估,而聚合物结晶形态和纤维取向状态均受模具中材料流动程度的控制。为了研究这些影响,对有机片材 (OS) 的全模具覆盖率和部分中心电荷 - 80%、60%、50% 和 40% 进行了压缩成型,以产生不同的各向异性材料流动。从模塑板上沿流动方向和横向切割出拉伸试样并进行测试,以比较其有效拉伸性能(模量和强度)。使用光学显微镜和 X 射线衍射分别表征了模塑复合材料在玻璃纤维束微观结构尺度和聚合物结晶相纳米结构尺度上由流动引起的形态变化。这些形态变化导致了拉伸强度和模量的显著变化;采用实验/数值模拟相结合的框架来分离各因素的相对贡献。实验结果表明,全模具覆盖和 OS-50 % 覆盖模具生产的试样在流动方向上的拉伸模量分别从 9.6GPa 增加到 14.9GPa。模具全覆盖和 OS-60 % 覆盖率生产的试样的拉伸强度从 162 兆帕增加到 254 兆帕。相反,流向横向的强度和模量却显著下降,分别为 35 兆帕和 3GPa, 这归因于 PA6 基体中纤维排列和各向异性的减少。


Thermoviscoelastic modelling of highly reactive thermoset resins for liquid moulding applications

Leonardo Barcenas, Loleï Khoun, Pascal Hubert

doi:10.1016/j.compositesa.2024.108350

用于液体成型应用的高活性热固性树脂的热变弹性建模

This paper presents a methodology for developing thermo-mechanical properties model for highly reactive resins and its use for Resin Transfer Moulding process (RTM) modelling and prediction of residual stresses. Cure Hardening Instantaneously Linear Elastic (CHILE), and Thermoviscoelastic (TVE) models, were implemented to analyze the mechanical behaviour of the resin. Simulation of the RTM process was developed and applied to a representative curved plate geometry. An integral approach was considered where the degree of cure gradient, generated during the filling stage due to the reactivity of the resin, was implemented as initial condition of the stress-deformation process simulation. The validation process included fabricating experimental parts with the representative geometry. The degree of cure variation of highly reactive thermosets during injection caused a significant effect on the final shape of the parts. These effects were captured by the simulations, where the TVE model showed a more accurate prediction of the part distortion.

本文介绍了一种开发高活性树脂热机械性能模型的方法,并将其用于树脂传递模塑工艺(RTM)建模和残余应力预测。采用固化硬化瞬时线性弹性模型(CHILE)和热变形弹性模型(TVE)来分析树脂的机械性能。对 RTM 过程进行了模拟,并将其应用于具有代表性的曲面板几何形状。考虑了一种整体方法,将填充阶段由于树脂反应性而产生的固化梯度作为应力-变形过程模拟的初始条件。验证过程包括制造具有代表性几何形状的实验部件。高活性热固性树脂在注塑过程中的固化程度变化对零件的最终形状有显著影响。模拟捕捉到了这些影响,其中 TVE 模型对零件变形的预测更为准确。


Silicone elastomer dielectric composites by introducing novel O-MMT@TiO2 nanoparticles for energy harvesting application

Tao Yang, Chongyang Wang, Ling Liu, Liqun Zhang

doi:10.1016/j.compositesa.2024.108351

 

引入新型 O-MMT@TiO2 纳米粒子的硅树脂弹性体介电复合材料的能量采集应用

Dielectric elastomers have attracted attention in emerging advanced electromechanical applications. However, how to simultaneously improve the dielectric constant and the breakdown strength of dielectric composite needs to be solved. In this paper, we propose a new strategy to anchor TiO2 nanoparticles onto organically modified montmorillonite (O-MMT) nanoplatelets through dehydration reaction to synthesize a novel filler O-MMT@TiO2. Then, the O-MMT@TiO2 is incorporated into methyl vinyl silicone rubber (MVSR) matrix to obtain O-MMT@TiO2/MVSR dielectric composites. Comparing with the composites by direct mixing of TiO2 and O-MMT in MVSR (O-MMT/TiO2/MVSR), O-MMT@TiO2/MVSR composites significantly increase mechanical and dielectric and energy storage properties. 30 wt% O-MMT@TiO2/MVSR composite achieves the highest energy storage density of 118.65 kJ/m3, which is 142.9 % higher than that of 15 wt%O-MMT/15 wt%TiO2/MVSR (48.84 kJ/m3). This study offers an effective method for the preparation of high-performance dielectric elastomer materials, which can be exploited for the energy harvesting application.

介电弹性体在新兴的先进机电应用中备受关注。然而,如何同时提高介电复合材料的介电常数和击穿强度仍是一个亟待解决的问题。本文提出了一种新策略,即通过脱水反应将 TiO2 纳米颗粒锚定在有机改性蒙脱石(O-MMT)纳米颗粒上,合成新型填料 O-MMT@TiO2。然后,将 O-MMT@TiO2 加入甲基乙烯基硅橡胶(MVSR)基体中,得到 O-MMT@TiO2/MVSR 介电复合材料。与在 MVSR 中直接混合 TiO2 和 O-MMT 的复合材料(O-MMT/TiO2/MVSR)相比,O-MMT@TiO2/MVSR 复合材料显著提高了机械性能、介电性能和储能性能。30 wt% O-MMT@TiO2/MVSR 复合材料的储能密度最高,达到 118.65 kJ/m3,比 15 wt%O-MMT/15 wt%TiO2/MVSR 的储能密度(48.84 kJ/m3)高出 142.9%。这项研究为制备高性能介电弹性体材料提供了一种有效的方法,可用于能量收集应用。


Composites Part B: Engineering

An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Ali Shivaie Kojouri, Javane Karami, Kalliopi-Artemi Kalteremidou, Jialiang Fan, Akash Sharma, Anastasios P. Vassilopoulos, Veronique Michaud, Wim Van Paepegem, Danny Van Hemelrijck

doi:10.1016/j.compositesb.2024.111695

厚粘合剂接头 I 型断裂和裂缝扭结的实验和分析研究

This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an adhesive thickness of approximately 10 mm and different pre-crack lengths are manufactured and tested under mode I loading. Analytical approaches are compared to assess the energy release rate, including the simple beam theory, modified beam theory, compliance calibration method, and beam on an elastic and elastic-plastic foundation. In order to evaluate the applicability of the analytical approaches, an in-situ measurement method based on Digital Image Correlation is also employed to determine the energy release rate of the thick adhesive joints. The crack propagation angle is determined theoretically using the second-order crack kinking theory. A good correlation is observed between the theoretical predictions and experimental results. Furthermore, it is demonstrated that due to the T-stress, the crack tends to deviate from the middle of the joint and propagate towards the interface. By comparing different data reduction methods to evaluate the energy release rate of thick adhesive joints, recommendations for their fracture analysis are made, pinpointing the beam on an elastic and elastic-plastic foundation as the most suitable model.

本研究探讨了用复合材料粘合剂制造并用风力涡轮机行业常用的环氧基结构粘合剂粘合的厚粘合接头的断裂行为。为此,制作了粘合剂厚度约为 10 毫米、预裂缝长度不同的双悬臂梁试样,并在模式 I 载荷下进行了测试。比较了评估能量释放率的分析方法,包括简单梁理论、修正梁理论、顺应性校准方法以及弹性和弹塑性基础上的梁。为了评估分析方法的适用性,还采用了基于数字图像相关性的现场测量方法来确定厚粘合剂接头的能量释放率。裂缝扩展角是利用二阶裂缝扭结理论从理论上确定的。理论预测与实验结果之间存在良好的相关性。此外,实验还证明,由于 T 形应力的作用,裂纹倾向于偏离接头中部并向界面方向扩展。通过比较不同的数据还原方法来评估厚粘接接头的能量释放率,为其断裂分析提出了建议,并指出弹性和弹塑性基础上的梁是最合适的模型。


Composites Science and Technology

Bending shape memory properties and multi-scale viscoelastic behaviors of knitted-fabric reinforced polymer composites

Ying Huang, Haipeng Ren, Yang Liu, Weilin Xu, Wei Zhao

doi:10.1016/j.compscitech.2024.110747

 

针织织物增强聚合物复合材料的弯曲形状记忆特性和多尺度粘弹性行为

Knitted fabrics with easily deformable loop structure have the potential in the development of shape memory polymeric composites with large recovery deformations. The knitted fabric reinforced shape memory epoxy polymer composites (SMPC) were prepared in this work. The effects of loop densities, orientations and bending radii on shape memory properties of SMPC were investigated. The shape fixity ratio and shape recovery ratio of SMPC subjected to U-shaped bending radius of 5 mm are above 98%. The shape recovery force of SMPC can reach up to 5.9 N. The thermodynamic properties of SMP were also characterized to obtain mechanical parameters and a user-defined material subroutine (UMAT) of shape memory epoxy polymer (SMEP) was written. Based on viscoelastic theory and the multi-scale geometrical structures, the macroscopic homogeneous thermodynamic model and mesoscopic thermodynamic model of knitted fabric reinforced SMPC were established to study the macro-scale stress distribution and meso-scale deformation evolution during shape memory process, respectively. The neutral surface position of SMPC during bending deformation is offset inner. The unique anisotropic loop structure of knitted fabric determines the shape memory behavior of the SMPC. Finally, micro-CT characterizations of knitted fabric reinforced SMPC were conducted to further understand the loop deformation mechanism during shape memory process. This study will provide important theoretical and technical support for large deformation structure design and deformation prediction of smart composites.

具有易变形环状结构的针织物具有开发具有大恢复变形的形状记忆聚合物复合材料的潜力。本研究制备了针织物增强环氧聚合物形状记忆复合材料(SMPC)。研究了环密度、取向和弯曲半径对 SMPC 形状记忆性能的影响。在半径为 5 毫米的 U 形弯曲条件下,SMPC 的形状固定率和形状恢复率均在 98% 以上。还对 SMP 的热力学性质进行了表征,以获得力学参数,并编写了形状记忆环氧聚合物(SMEP)的用户自定义材料子程序(UMAT)。基于粘弹理论和多尺度几何结构,建立了针织物增强 SMPC 的宏观均匀热力学模型和中观热力学模型,分别研究了形状记忆过程中的宏观应力分布和中观变形演化。在弯曲变形过程中,SMPC 的中性面位置为内偏移。针织物独特的各向异性环状结构决定了 SMPC 的形状记忆行为。最后,对针织物增强的 SMPC 进行了显微 CT 表征,以进一步了解形状记忆过程中的环变形机制。这项研究将为智能复合材料的大变形结构设计和变形预测提供重要的理论和技术支持。



来源:复合材料力学仿真Composites FEM
ACTMechanicalOpticalMarcMAGNET振动断裂复合材料光学声学裂纹理论材料储能多尺度纺织
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【新文速递】2024年7月10日复合材料SCI期刊最新文章

今日更新:Composites Part A: Applied Science and Manufacturing 1 篇,Composites Science and Technology 2 篇Composites Part A: Applied Science and ManufacturingProcessing and performance of ultra high temperature ceramic matrix composite (UHTCMCs) using radio frequency assisted chemical vapour infiltration (RF-CVI)Vinothini Venkatachalam, Burkard Esser, Jon Binnerdoi:10.1016/j.compositesa.2024.108358利用射频辅助化学气相渗透(RF-CVI)加工超高温陶瓷基复合材料(UHTCMC)并提高其性能Ultra-high temperature ceramic matrix composites (UHTCMCs) have been produced using a radio frequency assisted chemical vapour infiltration (RF-CVI) process. The composites were based on 2.5D carbon fibre preforms with a 0 / 90° (out of plane) fibre orientation and containing 23 % fibre volume fraction. These were initially impregnated with zirconium diboride (ZrB2) powder in the form of a slurry and then, after solvent removal, the majority of the porosity filled with pyrolytic carbon (PyC) using the RF-CVI process at 1273 K and 0.5 kPa chamber pressure. The latter resulted in a uniform rough laminar texture with good interfacial bonding. As intended, an inverse temperature profile was achieved using the RF heating, enabling uniform densification of the preform from the inside out, with no entrapped porosity and achieving 90 % of theoretical density in only 24 h, at least a tenfold reduction in processing time compared to the conventional CVI process and a fivefold reduction compared to other modified CVI processes such as forced flow or pressure gradient CVI. The resulting UHTCMCs displayed good mechanical strength and thermo-ablative behaviour.超高温陶瓷基复合材料(UHTCMC)是利用射频辅助化学气相渗透(RF-CVI)工艺生产的。复合材料基于 2.5D 碳纤维预制件,纤维取向为 0/90°(平面外),纤维体积分数为 23%。在 1273 K 和 0.5 kPa 的室压下,使用 RF-CVI 工艺将二硼化锆(ZrB2)粉末以浆料形式浸渍,然后在去除溶剂后,用热解碳(PyC)填充大部分孔隙。后者产生了具有良好界面结合力的均匀粗糙层状纹理。如预期的那样,利用射频加热实现了反向温度曲线,使预型件从内向外均匀致密化,没有夹带孔隙,仅用 24 小时就达到了理论密度的 90%,与传统的 CVI 工艺相比,加工时间至少缩短了十倍,与强制流或压力梯度 CVI 等其他改良 CVI 工艺相比,缩短了五倍。所得 UHTCMC 具有良好的机械强度和热烧蚀性能。Composites Science and TechnologyAn interfacial interlocking strategy for upcycling wool textiles to prepare polypropylene composite via interfacial diffusion and assemblyJing Zhou, Wenyan Wang, Rui Han, Chun Zhang, Min Niedoi:10.1016/j.compscitech.2024.110745 通过界面扩散和组装,采用界面互锁策略提升羊毛纺织品的循环利用率,制备聚丙烯复合材料Substantial waste of wool textiles, along with a lack of effective treatment technology, has resulted in a significant resource and environmental constraints. Integrating wasted wool textiles with polymer is an effective way to prepare lightweight structural materials, but the resulting properties is closely linked to the interfacial interaction. Here, we proposed an interfacial manipulation strategy to direct interfacial diffusion and aggregation of amide-based nucleating agents (WBG) in polypropylene (PP)/wool fiber (WF) composites. Accordingly, the branched WBG fibers were anchored onto the WF surface to construct an interlocking interface between WF and PP so as to strengthen the interfacial interaction. The formation and regulation mechanism of the branched WBG fibers were demonstrated. Benefited from mechanical interlocking and β-nucleating function of the branched WBG fibers, the interfacial interaction between the WF and PP matrix was enhanced while the formation numerous β-PP was cultivated, endowing the composite with excellent strength and ductility. To demonstrate the application potential of this strategy, waste wool textiles were alternately embedded between WBG-containing PP sheets to create an interlocking interfacial laminate with an exceptional combination of strength and toughness, which is important to upcycle waste wool textiles.羊毛纺织品的大量废弃,加上缺乏有效的处理技术,造成了严重的资源和环境制约。将废弃羊毛纺织品与聚合物结合是制备轻质结构材料的有效方法,但其性能与界面相互作用密切相关。在此,我们提出了一种界面操作策略,以引导聚丙烯(PP)/羊毛纤维(WF)复合材料中酰胺基成核剂(WBG)的界面扩散和聚集。因此,支化的 WBG 纤维被锚定在 WF 表面,在 WF 和 PP 之间构建了一个互锁界面,从而加强了界面相互作用。实验证明了支化 WBG 纤维的形成和调节机制。得益于支化 WBG 纤维的机械互锁和 β 成核功能,WF 与 PP 基体之间的界面相互作用得到了增强,同时还促进了大量 β-PP 的形成,使复合材料具有优异的强度和延展性。为了证明这种策略的应用潜力,我们将废羊毛纺织品交替嵌入含 WBG 的 PP 片材之间,从而制造出一种交错的界面层压材料,其强度和韧性兼备,这对于废羊毛纺织品的回收利用非常重要。Nano-BN and nano-cellulose synergistically enhanced the mechanical, thermal, and insulating properties of cellulose insulating paperWenchang Wei, Yiyi Zhang, Haiqiang Chen, Zhicheng Su, Danquan Lan, Junwei Zhadoi:10.1016/j.compscitech.2024.110748 纳米-BN 和纳米纤维素协同增强了纤维素绝缘纸的机械、热和绝缘性能The complex and demanding environments of high humidity, heat, altitude, and intricate electric fields necessitate higher standards for the mechanical, thermal stability, and electric insulation properties of insulating paper. However, a single nanomaterial alone struggles to enhance overall performance. Hence, we propose employing two-phase nanomaterials with distinct dimensions to synergistically enhance the performance of cellulose insulation paper. Accordingly, "simulation design directly guided experimental research" was utilized in constructing nano-BN/nanocellulose/cellulose (nano-BN/NFC/cellulose) models through molecular dynamics simulation, and its mechanical parameters, dielectric properties, thermal stability, and so on were simulated and calculated. Based on simulation results, suitable proportions of nano-BN/NFC/cellulose insulating paper were prepared. Nano-BN and NFC synergistically enhance the mechanical properties of insulating paper. The nano-BN, CNF, and cellulose are arranged layer by layer under the action of gravity, allowing the fillers to overlap diagonally along the plane, synergistically forming a thermally conductive network conducive to heat transfer. Additionally, a strong interfacial effect is formed between the three-phase materials, reducing the overall structure's polarization effect and charge accumulation, and synergistically enhancing electrical insulation performance. The 12%nano-BN/NFC/cellulose (P12) exhibits optimal overall performance and is expected to be used in power equipment operating in special environments with high humidity and heat.高湿、高热、高海拔和复杂电场等复杂苛刻的环境要求对绝缘纸的机械性能、热稳定性和电绝缘性能提出更高的标准。然而,单靠一种纳米材料很难提高整体性能。因此,我们建议采用不同尺寸的两相纳米材料来协同提高纤维素绝缘纸的性能。因此,我们采用 "模拟设计直接指导实验研究 "的方法,通过分子动力学模拟构建了纳米 BN/纳米纤维素/纤维素(nano-BN/NFC/cellulose)模型,并对其力学参数、介电性能、热稳定性等进行了模拟和计算。根据模拟结果,制备出了合适比例的纳米-BN/NFC/纤维素绝缘纸。纳米 BN 和 NFC 协同增强了绝缘纸的机械性能。在重力作用下,纳米-BN、CNF 和纤维素逐层排列,使填料沿平面对角重叠,协同形成有利于热传递的导热网络。此外,三相材料之间形成了强烈的界面效应,降低了整体结构的极化效应和电荷积累,协同提高了电气绝缘性能。12%nano-BN/NFC/cellulose (P12) 具有最佳的整体性能,有望用于在高湿度和高热量的特殊环境中运行的电力设备。来源:复合材料力学仿真Composites FEM

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