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【新文速递】2023年12月29日复合材料SCI期刊最新文章

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今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 3 篇

Composite Structures

A multiscale interfacial cyclic debonding model for fibre-reinforced composites using micromechanics and molecular dynamics

Danhui Yang, Yu Sun, Jin Zhou, Gongshuai Wei, Zhongwei Guan, Xuefeng Chen

doi:10.1016/j.compstruct.2023.117831

利用微力学和分子动力学建立纤维增强复合材料的多尺度界面循环脱粘模型

In this study, a novel multiscale model based on the finite-volume direct averaging micromechanics (FVDAM) theory and molecular dynamics (MD) was developed to predict the interfacial cyclic debonding behaviour of composites. At the microscale, a solid interface with accumulated damage was incorporated using FVDAM, which enabled the simulation of both localised and homogenised interfacial damage responses under cyclic loading; a significant reduction in strength was observed after 10 loading cycles, implying the interfacial damage accumulation. At the atomic-scale, an interface model was built and subjected to cyclic loadings using MD simulation; the stress peak after 5 cycles was approximately half of the initial value, which provides damage parameters for upper-scale calculations and reveals the fundamental mechanism of interfacial cyclic debonding. The experimental data of unidirectional SCS-6/Ti-15-3 composites under cyclic loading were adopted to verify the proposed model. Furthermore, the influence of thermal residual stress and fibre orientation was investigated, which offers valuable insights for composite design and manufacturing.

本研究基于有限体积直接平均微观力学(FVDAM)理论和分子动力学(MD)开发了一种新型多尺度模型,用于预测复合材料的界面循环脱粘行为。在微观尺度上,使用 FVDAM 将具有累积损伤的固体界面纳入其中,从而能够模拟循环加载下的局部和均匀界面损伤响应;在 10 个加载周期后观察到强度显著降低,这意味着界面损伤累积。在原子尺度上,建立了界面模型,并利用 MD 模拟对其进行循环加载;5 个循环后的应力峰值约为初始值的一半,这为上尺度计算提供了损伤参数,并揭示了界面循环脱粘的基本机制。采用循环加载下单向 SCS-6/Ti-15-3 复合材料的实验数据验证了所提出的模型。此外,还研究了热残余应力和纤维取向的影响,为复合材料的设计和制造提供了有价值的见解。


Composites Part A: Applied Science and Manufacturing

Reactive Extrusion Additive Manufacturing of a Short Carbon Fiber Thermosetting Composite via Active Mixing

Pratik Koirala, Robert Pavlovic, Athena Aber, Michael J. Fogg, Cole Mensch, Carolyn C. Seepersad, Mehran Tehrani

doi:10.1016/j.compositesa.2023.107989

通过活性混合实现短碳纤维热固性复合材料的反应挤出增材制造

Reactive extrusion additive manufacturing (REAM) is a recently developed process that utilizes reactive thermoset resin-hardener systems that are mixed inside a shearing element, deposited layer by layer to form a structure, and cured in-situ without external energy. An externally powered active mixing element was developed and used to demonstrate REAM with a highly viscous resin that was filled with 10 wt.% chopped carbon fibers. This was achieved by adding fumed silica and increasing the temperature of the fiber-resin mixture to enable effective in-situ mixing while maintaining shape retention upon deposition. Tensile properties of fiber-reinforced and reference REAM parts were measured and explained using their fiber alignment and length distribution. Finally, a mechanics model was utilized to determine the optimal short fiber content for strength and stiffness, considering the degradation of fiber length at higher volume fractions due to the mixing.

反应挤压增材制造(REAM)是最近开发的一种工艺,它利用反应热固性树脂-固化剂系统在剪切元件内混合,逐层沉积形成结构,并在无外部能量的情况下就地固化。我们开发了一种外部驱动的活性混合元件,并用它来演示 REAM 与高粘度树脂的混合,其中填充了 10 wt.% 的切碎碳纤维。这是通过添加气相二氧化硅和提高纤维-树脂混合物的温度来实现的,从而实现有效的原位混合,同时在沉积时保持形状不变。测量了纤维增强部件和参考 REAM 部件的拉伸性能,并利用其纤维排列和长度分布进行了解释。最后,利用力学模型确定了强度和刚度的最佳短纤维含量,同时考虑到了混合造成的较高体积分数下的纤维长度退化。


Converting bio-waste rice into ultralight hierarchical porous carbon to pack polyethylene glycol for multifunctional applications:Experiment and molecular dynamics simulations

Pei Li, Daili Feng, Yanhui Feng, Xinxin Zhang

doi:10.1016/j.compositesa.2023.107979

 

将生物废料稻米转化为超轻分层多孔碳,以封装聚乙二醇,实现多功能应用:实验与分子动力学模拟

A structural-functional integrated shape-stabilized composite phase change material (PCM) was synthesized by converting biowaste rice into ultralight (0.08 g/cm3) hierarchical porous carbon (CNR) to pack polyethylene glycol (PEG) PCM. The thermal property and corresponding mechanism were analyzed. The results show that the composite PCM exhibits excellent thermal storage efficiency (93.3%), considerable solar photothermal conversion efficiency and superior thermal stability. The interfacial thermal resistance (ITR) of PEG/CNR is 73% lower than graphene foam-based composite PCM thus a fast transient temperature response. Particularly, the package of PEG endowed composite PCM with elastic characteristic thereby an enhanced compressive strength. Furthermore, covering PEG/CNR results in a delay of approximately 1.3 times in reaching the peak temperature on the surface of electronic components, and a delay of 5 times in cooling time. This study presents solid guidelines for societal development that is sustainable and makes some recommendations for construction of composite PCMs combining multifunctional applications.

通过将生物废料大米转化为超轻(0.08 g/cm3)分层多孔碳(CNR)来封装聚乙二醇(PEG)PCM,合成了一种结构功能一体化的形状稳定复合相变材料(PCM)。对其热性能和相应的机理进行了分析。结果表明,复合 PCM 具有出色的蓄热效率(93.3%)、可观的太阳能光热转换效率和卓越的热稳定性。PEG/CNR 的界面热阻(ITR)比基于石墨烯泡沫的复合 PCM 低 73%,因此具有快速的瞬态温度响应。特别是,PEG 包裹赋予了复合 PCM 弹性特性,从而提高了抗压强度。此外,覆盖 PEG/CNR 可使电子元件表面达到峰值温度的时间延迟约 1.3 倍,冷却时间延迟 5 倍。本研究为社会的可持续发展提供了可靠的指导方针,并为构建多功能应用的复合 PCM 提出了一些建议。


Interfacial engineering of hybrid MXene-Ni-CF tri-core-shell composites for electromagnetic interference shielding and E-heating applications

Yi Hu, Guoyu Yang, Junzhen Chen, Yujun Li, Ming Dong, Han Zhang, Emiliano Bilotti, Jianjun Jiang, Dimitrios G. Papageorgiou

doi:10.1016/j.compositesa.2023.107990

用于电磁干扰屏蔽和电加热应用的混合 MXene-Ni-CF 三核壳复合材料的界面工程设计

In response to the the needs for multifunctional carbon fiber reinforced polymer (CFRP) composites, we present a novel, tri-core-shell CFRP consisting of MXene, nickel (Ni), and CF synthesized throughlayer-by-layer assembly. The hybridcomposites demonstrate remarkable electrical conductivity and electromagnetic interference (EMI) shielding, alongside efficient electrical (E-) heating properties. Additionally, the MXene-Ni-CF/EP hybrid composite displayed improved flexural strength and ILSS compared to Ni-CF/EP composite. Outstanding enhancements were observed in both the through-thickness and in-plane electrical conductivities, with a 116-fold and 14-fold improvement, respectively, attributed to the complex MXene-Ni-CF conductive paths. The hierarchical compositessignificantly outperformed the state of the art and demonstrated a superior EMI shielding efficiency of 72.4 dB by virtue of the dielectric and magnetic loss mechanisms. Thelow-voltage-driven E-heating capacity could be utilized for de-icing applications due to the thermally conductive networks. The producedcomposites offer a highly promising solution to tackle challenges associated with lightning strikes and icy weather conditions, while also aligning with the goal of cost-effective industrial production.

为了满足对多功能碳纤维增强聚合物(CFRP)复合材料的需求,我们提出了一种新型三核壳 CFRP,由 MXene、镍(Ni)和 CF 通过逐层组装合成。这种混合复合材料具有出色的导电性、电磁干扰(EMI)屏蔽性和高效的电热(E-)性能。此外,与 Ni-CF/EP 复合材料相比,MXene-Ni-CF/EP 混合复合材料显示出更高的抗弯强度和 ILSS。由于 MXene-Ni-CF 复合导电路径的存在,通厚导电率和面内导电率都得到了显著提高,分别提高了 116 倍和 14 倍。分层复合材料的性能明显优于目前的技术水平,并凭借介电和磁损耗机制表现出 72.4 dB 的卓越 EMI 屏蔽效率。由于具有导热网络,低电压驱动的电热能力可用于除冰应用。所生产的复合材料为应对与雷击和冰雪天气条件相关的挑战提供了一种极具前景的解决方案,同时也符合成本效益工业生产的目标。


Composites Part B: Engineering

Multinanolayered PA6/Cloisite and PE/PA6/Cloisite composites: Structure, mechanical and barrier properties

Stéphane Marais, Quentin Lozay, Nadège Follain, Jérémie Soulestin, Nicolas Couvrat, Eric Dargent

doi:10.1016/j.compositesb.2023.111167

多纳层 PA6/Cloisite 和 PE/PA6/Cloisite 复合材料:结构、机械和阻隔性能

Economic and environmental challenges are driving development towards more efficient and lighter materials. Polyethylene (PE) and polyamide (PA6) are among the most used polymers and their assembly in multilayer make them efficient protective materials. The aim of this work is to design new multilayer composite films based on polyethylene and polyamide with high barrier properties. A coextrusion process with layer multiplier elements (LME) made it possible to carry out 100 μm-thick multilayer films containing 5 up to 1025 layers. Loaded PE/PA6 multilayer films were made by incorporating Cloisite particles (organo-modified montmorillonite – C30B) at 5 wt% into the PA6 layers. For comparison PA6 films with and without fillers were also made by using the same coextrusion process. The structural and thermal properties of all multilayer films were correlated with the water and gas barrier properties. A good dispersion of exfoliated C30B in the PA6 phase was observed even for the thinnest confined layers of PA6 in PE/PA6 multilayers (∼90 nm). We showed the complexity of the multinanolayer structures involving interphases as well as the complexity of the transfer mechanisms. The serial model used for predicting permeability highlighted some significant improvements of the gas barrier properties of confined PA6 layers. The barrier effect on all the multilayer films was, however, limited due to the “on-edge” orientation of the crystalline phases and structural defects induced during the coextrusion process. Despite this, the confinement of nanofillers in PA6 multilayers and in PA6 layers of PE/PA6 multilayers allowed to increase the barrier properties of multilayers.

经济和环境方面的挑战促使人们向更高效、更轻质的材料发展。聚乙烯(PE)和聚酰胺(PA6)是最常用的聚合物之一,它们的多层组合使其成为高效的防护材料。这项工作的目的是以聚乙烯和聚酰胺为基础,设计出具有高阻隔性能的新型多层复合薄膜。采用层乘法元件(LME)的共挤工艺,可以生产出厚度为 100 μm 的多层薄膜,层数从 5 层到 1025 层不等。通过在 PA6 层中加入 5 wt% 的 Cloisite 颗粒(有机改性蒙脱石 - C30B),制成了负载 PE/PA6 多层薄膜。为了进行比较,还采用相同的共挤工艺制作了含填料和不含填料的 PA6 薄膜。所有多层薄膜的结构和热性能都与水和气体阻隔性能相关。即使在 PE/PA6 多层膜中最薄的 PA6 封闭层(∼90 nm)中,也能观察到剥离的 C30B 在 PA6 相中的良好分散。我们展示了涉及相间的多层结构的复杂性以及转移机制的复杂性。用于预测渗透性的序列模型突出显示了密闭 PA6 层气体阻隔性能的一些显著改善。然而,由于结晶相的 "边缘 "取向以及共挤过程中产生的结构缺陷,所有多层薄膜的阻隔效果都受到了限制。尽管如此,纳米填料在 PA6 多层膜和 PE/PA6 多层膜的 PA6 层中的限制作用还是提高了多层膜的阻隔性能。


Silk fibroin/polyacrylamide-based tough 3D printing scaffold with strain sensing ability and chondrogenic activity

Yanan Geng, Tiexin Liu, Menglu Zhao, Haifeng Wei, Xiang Yao, Yaopeng Zhang

doi:10.1016/j.compositesb.2023.111173

 

基于丝纤维素/聚丙烯酰胺的具有应变传感能力和软骨活性的坚韧 3D 打印支架

Cartilage tissue plays an important role in our life activities. The poor self-repair capacity makes cartilage tissue engineering an urgent clinical demand. Among them, the development of tissue engineering scaffolds with both biomimetic features and microenvironment signal sensing abilities could significantly promote the development of cartilage tissue engineering. While most of the reported cartilage scaffolds have no intelligent sensing features. Herein, a ternary composite 3D printing scaffold with both strain sensing ability and desired mechanical property was developed, by using regenerated silk fibroin (RSF) and polyacrylamide (PAM) as main matrixes, and oxidized bacterial cellulose nanofibers (OBC) as filler. Then, the mechanical property, strain sensing ability and corresponding ectopic chondrogenic activity of the RSF/PAM/OBC 3D printing scaffold were comprehensively investigated and verified through in vitro and in vivo studies. Results showed that the RSF/PAM/OBC (OBC-6.3 wt%) scaffold owns effective strain sensing property and desired ectopic chondrogenesis capabilities in the subcutaneous microenvironment. It could be used for reliable monitoring the joint movements, related motion amplitudes, and also promoting the cartilage specifical genes expression. These features not only confirmed the great potential of these smart scaffolds for applications in tissue reconstruction and mechanical stimulus monitoring of the corresponding tissue microenvironment, but also proved the possibility of employing various 3D printing scaffolds as flexible bioelectronics.

软骨组织在我们的生命活动中发挥着重要作用。软骨组织自我修复能力差,因此软骨组织工程成为临床的迫切需求。其中,具有生物仿生功能和微环境信号传感能力的组织工程支架的开发将极大地促进软骨组织工程的发展。而目前报道的软骨支架大多不具备智能传感功能。本文以再生蚕丝纤维素(RSF)和聚丙烯酰胺(PAM)为主要基质,以氧化细菌纤维素纳米纤维(OBC)为填充物,开发了一种兼具应变传感能力和理想力学性能的三元复合3D打印支架。然后,通过体外和体内研究全面考察和验证了RSF/PAM/OBC三维打印支架的力学性能、应变传感能力和相应的异位软骨活性。结果表明,RSF/PAM/OBC(OBC-6.3 wt%)支架在皮下微环境中具有有效的应变传感特性和理想的异位软骨生成能力。它可用于可靠监测关节运动和相关运动幅度,还能促进软骨特异性基因的表达。这些特点不仅证实了这些智能支架在组织重建和相应组织微环境的机械刺 激监测方面的巨大应用潜力,还证明了将各种三维打印支架用作柔性生物电子器件的可能性。


Composites Science and Technology

Energy release rate for steady-state fiber debonding in structural battery composites

Kai Guo, N. Sridhar, Choon Chiang Foo, Bharathi Madurai Srinivasan

doi:10.1016/j.compscitech.2023.110416

 

电池结构复合材料稳态纤维脱粘的能量释放率

Structural battery composites are multifunctional materials intended to provide energy storage capacity while maintaining their strength and load bearing capacity under significant mechanical loads. In this study, we investigate the mechanics of carbon fiber debonding, a critical failure mechanism in structural battery composites. The carbon fibers are intended to serve both as an electrochemically active material and to bear mechanical load in the composite system. We derive an analytical solution to the energy release rate for steady-state fiber debonding for different electrochemical and mechanical loading cases with the aid of the classical solution for the Eshelby inclusion problem. The analytical solutions are validated with finite element simulations. We find a higher energy release rate and thus a greater driving force for fiber debonding is caused either by a lower lithium concentration in the fiber and/or by greater transverse mechanical loads such as biaxial tension or shear applied at the far field in the matrix. We find that the model is predictive even for transversely isotropic fibers despite the assumption that the fiber is elastically isotropic in the model. This work can provide guidance for the design of mechanically robust structural batteries.

结构电池复合材料是一种多功能材料,旨在提供储能能力,同时在巨大的机械负荷下保持强度和承载能力。在本研究中,我们对结构性电池复合材料中的一个关键失效机理--碳纤维脱粘进行了力学研究。碳纤维既是电化学活性材料,也是复合材料系统中的机械载荷。我们借助埃舍尔比包容问题的经典解决方案,得出了不同电化学和机械负载情况下稳态纤维脱胶能量释放率的分析解决方案。有限元模拟验证了分析解。我们发现,由于纤维中的锂浓度较低,和/或由于在基体远场施加了更大的横向机械负荷(如双轴拉力或剪切力),纤维的能量释放率较高,因此纤维脱胶的驱动力较大。我们发现,尽管在模型中假设纤维是弹性各向同性的,但该模型甚至对横向各向同性纤维也具有预测性。这项工作可为设计机械坚固的结构电池提供指导。


A three-dimensional failure criterion model considering the effects of fiber misalignment on longitudinal tensile failure

Naiyu Liu, Puhui Chen

doi:10.1016/j.compscitech.2023.110424

 

考虑纤维错位对纵向拉伸失效影响的三维失效准则模型

This paper proposes a three-dimensional failure criterion model for unidirectional fiber-reinforced composites. In contrast to previous models that only accounted for the effect of fiber misalignment in the presence of longitudinal compressive stress, the proposed failure criterion model comprehensively considers the effect of localized misaligned regions on the failure under any stress state. Another key contribution of this study is the introduction of the effective misalignment angle. Considering effective misalignment angles, the proposed failure criterion model can reasonably reveal the effect of localized misaligned regions on the failure behavior under different stress states. The agreement between the predicted results and the experimental data proves that the proposed model has good applicability. Furthermore, the influence of initial misalignment angles on failure is analyzed under varying stress conditions. The results indicate that even under longitudinal tensile stress, the initial misalignment angle still plays an important role in the failure behavior of materials.

本文提出了单向纤维增强复合材料的三维失效准则模型。与以往仅考虑纵向压应力作用下纤维错位影响的模型不同,本文提出的失效准则模型全面考虑了任何应力状态下局部错位区域对失效的影响。本研究的另一个重要贡献是引入了有效错位角。考虑到有效错位角,所提出的失效准则模型可以合理地揭示局部错位区域在不同应力状态下对失效行为的影响。预测结果与实验数据之间的一致性证明了所提出的模型具有良好的适用性。此外,还分析了在不同应力条件下初始错位角对破坏的影响。结果表明,即使在纵向拉伸应力下,初始错位角仍对材料的破坏行为起着重要作用。


Modelling the damage evolution in unidirectional all-carbon hybrid laminates

Amaury Ollic, Fariborz Sheibanian, Babak Fazlali, Yentl Swolfs, Stepan V. Lomov, Valter Carvelli

doi:10.1016/j.compscitech.2023.110420

 

单向全碳混合层压板损伤演变建模

Hybrid reinforcements for composites have been extensively studied and adopted to overcome the lack of ductility via pseudo-ductility. Thin-ply all-carbon interlayer hybrid laminates have attracted attention for their peculiar pseudo-ductile tensile response. At the same time, conventional thick plies have been barely considered. This work developed a finite element model to simulate the complex tensile damage scenario of unidirectional thin- and thick-ply all-carbon interlayer hybrid laminates. The damage modes intended in the numerical model were fragmentation in the low-elongation (LE) plies, and delamination of LE and high-elongation (HE) ply interfaces. Thin- and thick-ply hybrid laminates were modelled and compared to available experiments. The numerical model was also adopted to simulate different layups to predict the effect of LE thickness fraction on the pseudo-ductile tensile behaviour and the evolution of damage modes. As suggested in the literature, the results allowed us to depict the damage mode map of the considered hybrid laminates. The map distinguishes the all-carbon hybrid laminate configurations with pseudo-ductile and brittle tensile responses.

为了通过假韧性克服延展性不足的问题,人们对复合材料的混合增强材料进行了广泛的研究和采用。薄层全碳夹层混合层压板因其奇特的假延展拉伸响应而备受关注。与此同时,传统的厚层板几乎没有被考虑。本研究开发了一种有限元模型,用于模拟单向薄层和厚层全碳夹层混合层压板的复杂拉伸损伤情况。数值模型中的损伤模式为低伸长率(LE)层的碎裂以及 LE 和高伸长率(HE)层界面的分层。对薄层和厚层混合层压板进行了建模,并与现有实验进行了比较。数值模型还用于模拟不同的层叠结构,以预测 LE 厚度对伪韧性拉伸行为和损伤模式演变的影响。正如文献中建议的那样,研究结果使我们能够描绘出所考虑的混合层压板的损伤模式图。该图区分了具有假韧性和脆性拉伸响应的全碳混合层压板配置。




来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemMAGNET复合材料化学电路电子增材理论材料太阳能储能分子动力学多尺度仿生
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【新文速递】2024年1月1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 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇Composite StructuresInfluence of compaction and curing in the Automated Fiber Placement Process on the mechanical performance of composite laminatesSylvester Vogl, Ralf Knott, Silvano Sommacal, Paul Compston, Klaus Drechslerdoi:10.1016/j.compstruct.2023.117826自动纤维铺放工艺中的压实和固化对复合材料层压板机械性能的影响This paper investigates the effect of compaction and curing states on the mechanical properties and void content of AFP-manufactured laminates. For the mechanical characterization, tensile tests, 4-point-bending tests and interlaminar shear strength (ILSS) tests were applied. The internal structure was evaluated via micro CT. For the surface structure evaluation, an optical profilometer was used. The void content was determined via segmentation of the micro CT images. The paper is subdivided into the description of the applied materials and methods, the results and their discussion and a conclusion. The study showcases the potential of AFP-manufactured aerospace composites to attain high-quality results even without the need for an autoclave, making them well-suited for unmanned applications.本文研究了压实和固化状态对 AFP 制造的层压板的机械性能和空隙率的影响。在机械性能表征方面,采用了拉伸试验、4 点弯曲试验和层间剪切强度(ILSS)试验。内部结构通过微型 CT 进行评估。表面结构评估则使用了光学轮廓仪。通过对微型 CT 图像进行分割,确定了空隙含量。本文分为应用材料和方法描述、结果及其讨论和结论。该研究展示了 AFP 制造的航空航天复合材料的潜力,即使无需高压灭菌也能获得高质量的结果,使其非常适合无人驾驶应用。Enhanced prediction of transverse mechanical behavior of unidirectional fiber-reinforced composites using new spatial descriptors based on deep neural networksSun Won Kim, Jae Hyuk Lim, Seong Su Kimdoi:10.1016/j.compstruct.2023.117870利用基于深度神经网络的新空间描述符增强单向纤维增强复合材料横向力学行为的预测能力In this study, we developed a data-driven approach using a deep neural network (DNN) to predict the nonlinear stress-strain behavior of fiber-reinforced composites under transverse tensile loading. We explored the impact of different input features characterizing the composite microstructure on the prediction accuracy of the DNN model. Specifically, we introduced a spatial descriptor representing fiber arrangement and proposed new spatial descriptors based on fiber area to improve input feature quality. Incorporating widely-used spatial descriptors such as the second-order intensity function and radial distribution function improved the prediction performance compared to previous methods. Combining spatial descriptors for both fiber distribution and alignment further enhanced prediction accuracy. To address the limitations of conventional spatial descriptors, we developed new spatial descriptors using a continuous function. Our findings demonstrate the importance of selecting appropriate input features for improved DNN model performance, even with the same dataset. Moreover, the proposed fiber area-based spatial descriptors offer insights into the micromechanical behavior of composite materials.在这项研究中,我们利用深度神经网络(DNN)开发了一种数据驱动方法,用于预测横向拉伸载荷下纤维增强复合材料的非线性应力应变行为。我们探索了表征复合材料微观结构的不同输入特征对 DNN 模型预测精度的影响。具体来说,我们引入了代表纤维排列的空间描述符,并提出了基于纤维面积的新空间描述符,以提高输入特征的质量。与之前的方法相比,结合二阶强度函数和径向分布函数等广泛使用的空间描述符提高了预测性能。结合纤维分布和排列的空间描述符进一步提高了预测精度。为了解决传统空间描述符的局限性,我们使用连续函数开发了新的空间描述符。我们的研究结果表明,即使使用相同的数据集,选择适当的输入特征对于提高 DNN 模型性能也非常重要。此外,所提出的基于纤维面积的空间描述符为复合材料的微观机械行为提供了见解。Mechanical vibration absorber for flexural wave attenuation in multi-materials metastructureLong Liu, Ji Wan Kim, Gil Ho Yoon, Bing Yidoi:10.1016/j.compstruct.2023.117859用于衰减多材料结构中挠曲波的机械减震器Vibration isolation is a promise to suppress mechanical vibration from a host structure, similarly, a mechanical vibration absorber, a simple but effective device to attenuate flexural wave propagation, which has been implemented in civil and mechanical engineering. This paper presents a type of composite sandwich phononic crystal to attenuate the flexural wave propagation in a beam structure, which can effectively suppress mechanical vibration in a broad band gap by repetitively arranging phononic crystal. First, the elastic wave dispersion characteristic in a composite sandwich beam structure is derived, and a triangular shape phononic crystal for flexural wave attenuation by taking advantage of destructive interference is presented. Then two dimensional phononic crystals are designed by assembling four different unit-cells of metabeam. Finally, numerical experiments are conducted to verify the effectiveness of the proposed mechanical metamaterial absorbers to attenuate flexural wave propagation, the numerical results indicate that the proposed metamaterial is of good performance in mechanical vibration suppression, which can effectively mitigate structure vibration in low-frequency domain than the structure without phononic crystal and single layer metamaterial beam structure. It is the first attempt to design a mechanical metamaterial absorber with the mechanism of destructive interference with composite sandwich phononic crystal.隔振是一种抑制来自主机结构的机械振动的承诺,同样,机械吸振器也是一种简单而有效的衰减挠性波传播的装置,在土木工程和机械工程中已经得到了应用。本文提出了一种用于衰减梁结构中挠曲波传播的复合夹层声子晶体,通过重复排列声子晶体,可有效抑制宽带隙中的机械振动。首先,推导了复合夹层梁结构中的弹性波色散特性,并提出了一种利用破坏性干涉来衰减挠曲波的三角形声子晶体。然后,通过组装四个不同的元梁单元,设计了二维声子晶体。最后,通过数值实验验证了所提出的机械超材料吸波材料对挠性波传播的衰减效果,数值实验结果表明,所提出的超材料在机械振动抑制方面具有良好的性能,与不含声子晶体的结构和单层超材料梁结构相比,能有效缓解结构在低频域的振动。这是首次尝试利用复合夹层声子晶体的破坏性干涉机制设计机械超材料吸波材料。Composites Part A: Applied Science and ManufacturingSpatial variability characterization and modelling of 2.5D woven SiO2f/SiO2 compositesHongyue Wang, Bing Wang, Maoqing Fu, Guodong Fang, Songhe Mengdoi:10.1016/j.compositesa.2023.107997 2.5D SiO2f/SiO2 编织复合材料的空间变化特征和建模2.5D woven SiO2f/SiO2 composites possess geometric variabilities across scales, such as the spatial fluctuations of fibers and yarns or the random distributions of defects and pores formed in the manufacturing process, which induces a complex stress and strain distribution in material testing. In this study, a multivariate cross-correlated non-Gaussian random field based on Vine Copula is proposed to characterize the spatial variability of mechanical properties. A database of material mechanical properties is acquired by stochastic representative volume element (SRVE) simulation results which contains realistic meso-geometry characteristics and spatially random voids. Based on this database, the cross- and auto-correlations of the mechanical properties are quantified by Vine Copula and non-Gaussian random field model. In a comparison of different numerical models and experimental results, the proposed method is verified, which shows great advantages in characterizing the spatial variability and big potential abilities in damage or reliability analysis.2.5D SiO2f/SiO2 编织复合材料具有跨尺度的几何变异性,如纤维和纱线的空间波动或制造过程中形成的缺陷和孔隙的随机分布,从而在材料测试中引起复杂的应力和应变分布。本研究提出了一种基于 Vine Copula 的多元交叉相关非高斯随机场,用于描述力学性能的空间变异性。材料力学性能数据库由随机代表体积元素(SRVE)模拟结果获得,其中包含真实的中间几何特征和空间随机空隙。在该数据库的基础上,采用 Vine Copula 和非高斯随机场模型对力学性能的交叉和自相关性进行了量化。通过比较不同的数值模型和实验结果,验证了所提出的方法在表征空间变异性方面的巨大优势,以及在损伤或可靠性分析方面的巨大潜力。Functionalizing chitosan-based film with highly sensitive fire response and commendable flame retardancy for intelligent fire-alarm systemRongkai Wu, Yu Wang, Yunyirui Liu, Bihe Yuandoi:10.1016/j.compositesa.2023.107999 将壳聚糖基薄膜功能化,使其具有高度灵敏的火灾反应和值得称赞的阻燃性能,用于智能火灾报警系统Recently, the extensive use of combustible materials has amplified building fire damage, making it essential to incorporate fire-detection devices and flame-retardant materials in building. Herein, the chitosan/gelatin (CG) film and KH2PO4-modified CG (KCG) films were fabricated via an eco-friendly water evaporation method. Impressively, KCG films demonstrate swift response times: 0.5 s at 100 ℃ and 1.8 s under flame, facilitating prompt alarms during fire incidents. Compared to CG, KCG achieve a 70.4% and 46.2% reduction in peak heat release rate and total heat release respectively. They also offer flexibility, transparency, repeated fire-warning efficacy and superior char formation. With these properties, KCG hold promise for innovative building fire safety solutions like smart fire-alarm wallpaper. Besides, a tailored wireless-based fire-alarm system for KCG further decreases building fire damage. This work mitigates damages arising from building fires work, marking significant leap forward in the use of bio-based materials for fire prevention in architecture.近年来,可燃材料的广泛使用加剧了建筑物的火灾损失,因此在建筑物中加入火灾探测装置和阻燃材料至关重要。本文采用环保的水蒸发法制作了壳聚糖/明胶(CG)薄膜和 KH2PO4 改性 CG(KCG)薄膜。令人印象深刻的是,KCG 薄膜的响应时间很快:在 100 ℃ 下为 0.5 秒,在火焰下为 1.8 秒,有助于在火灾事故中迅速报警。与 CG 相比,KCG 的峰值放热率和总放热率分别降低了 70.4% 和 46.2%。此外,KCG 还具有柔韧性、透明性、多次火灾预警效果和优异的炭化性能。凭借这些特性,KCG有望成为智能火警墙纸等创新型建筑消防安全解决方案的首选。此外,为 KCG 量身定制的基于无线的火灾报警系统还能进一步降低建筑火灾损失。这项工作减轻了建筑火灾造成的损失,标志着生物基材料在建筑防火领域的应用取得了重大飞跃。Composites Part B: EngineeringThe synergistic effect of greenhouse gas CO2 and silica fume on the properties of 3D printed mortarHao Lucen, Li Long, Zhang Shipeng, Zhang Huanghua, Xiao Jianzhuang, Poon Chi Sundoi:10.1016/j.compositesb.2023.111188温室气体二氧化碳和硅灰对 3D 打印砂浆性能的协同效应To fulfil the requirements of pumpability and buildability, the rheological properties of mortar/concrete for 3D printing should follow much stricter requirements than traditional-cast mortar/concrete. This study proposed to use a secondary CO2 mixing technique coupled with the addition of silica fume (SF) to achieve in-situ rheology control of 3D printed mortar. The influences of CO2 mixing on the properties of the cast mortar and the 3D printed mortar prepared with SF were systematically studied. The pH, conductivity and ion concentration were tested to revel the essential chemical reactions and phase evolutions during CO2 mixing. It was found that the CO2 mixing effectively enhanced the early-age penetration resistance and yield stress of mortar incorporated with SF, and thus significantly improved the buildability of 3D printed mortar, while the maximum printing layer increased higher than 33 layers. Meanwhile, the mechanical properties of the SF-incorporated mortar were improved by this process. It was revealed that during the CO2 mixing process, the injected CO2 rapidly reacted with calcium ions to form CaCO3, which further reacted with C3A to form monocarboaluminate (Mc). The fast precipitation of calcium ions during CO2 mixing accelerated the hydration of C3A and C3S, contributing to the rapid development of strength at early ages and the improved performance of hardened mortar. The addition of SF in mortar greatly amplified the beneficial effect of CO2 mixing, which due to SF as nucleation sites promoted the formation of CaCO3 and Mc during CO2 mixing.为了满足可泵性和可施工性的要求,3D 打印砂浆/混凝土的流变特性应遵循比传统浇注砂浆/混凝土更严格的要求。本研究建议采用二次二氧化碳混合技术,并添加硅灰(SF),以实现对 3D 打印砂浆的原位流变控制。该研究系统地研究了二氧化碳混合对浇注砂浆和用 SF 制备的 3D 打印砂浆性能的影响。测试了 pH 值、电导率和离子浓度,以揭示二氧化碳混合过程中的基本化学反应和相变。研究发现,CO2 混合能有效提高掺入 SF 的砂浆的早龄期抗渗透性和屈服应力,从而显著改善 3D 打印砂浆的可施工性,最大打印层数比 33 层更高。同时,该工艺还改善了掺入 SF 的砂浆的力学性能。研究发现,在二氧化碳混合过程中,注入的二氧化碳迅速与钙离子反应生成 CaCO3,再与 C3A 反应生成单碳铝酸盐(Mc)。CO2 混合过程中钙离子的快速析出加速了 C3A 和 C3S 的水化,有助于早期龄期强度的快速发展和硬化砂浆性能的改善。在砂浆中加入 SF 大大提高了 CO2 混合的有益效果,因为 SF 是成核场所,在 CO2 混合过程中促进了 CaCO3 和 Mc 的形成。Composites Science and TechnologyA self-powered piezoelectric Poly(vinyl alcohol)/Polyvinylidene fluoride fiber membrane with alternating multilayer porous structure for energy harvesting and wearable sensorsYaru Yu, Xiaowen Zhao, Huaiguo Ge, Lin Yedoi:10.1016/j.compscitech.2023.110429 具有交替多层多孔结构的自供电压电聚(乙烯醇)/聚偏氟乙烯纤维膜,用于能量采集和可穿戴传感器Development of flexible wearable electronic devices requires high-performance piezoelectric sensors, being advantageous in high sensitivity, ease to microintegration without external power supply. In this work, poly(vinyl alcohol) (PVA)/polyvinylidene fluoride (PVDF) fiber membranes with stable alternating multilayer structure were constructed through electrospinning and subsequent gas-phase crosslinking. The PVA/PVDF fiber was fully stretched with smooth surface and uniform diameter at appropriate PVDF concentration, exhibiting high porosity (88 %). The α-phase was transformed into the electroactive β-phase of PVDF in the electrospinning process, while the crystallinity and β-phase percentage (Fβ) were improved by mixing spinning of PVA and PVDF, with Fβ reaching above 90 %. The PVA/PVDF fiber membrane showed high mechanical strength/toughness and liquid absorbency (719.03 %). The significant electrical signal output (10.07 V and 166.42 nA) was generated, accompanying with high stress sensitivity, short response time and high stability, exhibiting excellent piezoelectricity and making the fiber membrane not only monitor large deformation movements of limbs as self-powered wearable sensor, but also sense weak signals of pulse, breathing etc. for monitoring human health, as well as environmental humidity. Meanwhile, the harvested energy could drive electronic device, showing prosperous potentials in fields of artificial intelligence.柔性可穿戴电子设备的开发需要高性能的压电传感器,这些传感器具有灵敏度高、易于微集成且无需外部电源等优点。在这项工作中,通过电纺丝和随后的气相交联,构建了具有稳定交替多层结构的聚乙烯醇(PVA)/聚偏氟乙烯(PVDF)纤维膜。在适当的 PVDF 浓度下,PVA/PVDF 纤维完全拉伸,表面光滑,直径均匀,孔隙率高(88%)。在电纺丝过程中,PVDF 的 α 相转变为具有电活性的 β 相,而通过 PVA 和 PVDF 的混合纺丝,结晶度和 β 相百分比(Fβ)得到了改善,Fβ 达到了 90% 以上。PVA/PVDF 纤维膜具有较高的机械强度/韧性和吸液率(719.03%)。产生的电信号输出(10.07 V 和 166.42 nA)具有应力灵敏度高、响应时间短和稳定性高等特点,表现出优异的压电性,使纤维膜不仅能监测肢体的大变形运动,成为自供电的可穿戴传感器,还能感知脉搏、呼吸等微弱信号,用于监测人体健康和环境湿度。同时,采集到的能量可以驱动电子设备,在人工智能领域大有可为。来源:复合材料力学仿真Composites FEM

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