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【新文速递】2024年10月7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 2 篇,Composites Science and Technology 3 篇

Composite Structures

Broadband and robust vibration reduction in lattice-core sandwich beam with 3D-printed QZS resonators

Lei Xiao, Xiang Sun, Li Cheng, Xiang Yu

doi:10.1016/j.compstruct.2024.118626

3d打印QZS谐振器在格芯夹层梁中的宽带和鲁棒减振

The demand for lightweight lattice-core sandwich structures that exhibit superior mechanical and dynamic properties is widespread in many devices. This paper presents a lattice-core sandwich beam (LSB) with an embedded array of quasi-zero-stiffness (QZS) resonators, referred to as Q-LSB. This research distinguishes itself from existing studies on metamaterial structures with QZS resonators by investigating the nonlinear stiffness of QZS resonators and the damping of a soft three-dimensional (3D) printing material. The objective is to achieve efficient and robust vibration reduction beyond the band gap of its linear counterpart. We investigate the beam vibration using both experimental and numerical methods. The experimental results demonstrate that the resonators can entail significant vibration reduction in a wide frequency range, covering the first three eigenmodes of the host LSB. Furthermore, the reduction effect improves as the excitation level increases within the tested excitation range, highlighting the structure’s robustness against the excitation amplitude. A numerical model based on a dynamically equivalent homogenization method and the finite element method is established and experimentally validated. Subsequently, the numerical parametric results reveal that the broadband vibration reduction is due to the damping effect, while the robust vibration reduction effect is attributed to the nonlinear stiffness of the resonators.

在许多器件中,对具有优异力学和动态性能的轻质格芯夹层结构的需求是广泛存在的。本文提出了一种嵌入准零刚度(QZS)谐振器阵列的格芯夹层梁(LSB),简称Q-LSB。本研究通过研究QZS谐振器的非线性刚度和软三维(3D)打印材料的阻尼,与现有的QZS谐振器超材料结构研究不同。目标是实现有效和稳健的减振超出其线性对应的带隙。我们用实验和数值方法研究了梁的振动。实验结果表明,谐振器可以在较宽的频率范围内显著降低振动,覆盖宿主LSB的前三个特征模态。此外,在测试的激励范围内,随着激励水平的增加,减少效果也会改善,这突出了结构对激励幅度的鲁棒性。建立了基于动态等效均匀化法和有限元法的数值模型,并进行了实验验证。随后,数值参数分析结果表明,宽带减振是由于阻尼效应,而鲁棒减振是由于谐振器的非线性刚度。


Fracture simulation of fiber reinforced composite panels with holes

Yang Zhang, Jialu Guo, Zhan Shu, Yaojing Guan, A.S. Ademiloye

doi:10.1016/j.compstruct.2024.118627

带孔纤维增强复合材料板断裂模拟

Fiber reinforced composite (FRC) with holes have broad applications in various fields. In this study, the influence of fiber orientation and hole distribution on the fracture behavior of FRC was investigated. A phase-field modeling was established to simulate the fracture process of the composite, and the mechanical performance of unidirectional fiber reinforced composite and woven fiber reinforced composite were analyzed, respectively. Our numerical results showed that fiber orientation and hole distribution have a significant impact on the fracture behavior of FRC. We observed that aligning the fibers parallel to the loading direction led to an increase in the maximum load bearing capacity of the composite. A more uniform hole distribution can enhance the overall mechanical performance of FRC. Furthermore, in the presence of thermal shock, crack propagation tends to grow towards the hole. These findings are of great significance for understanding the fracture behavior of FRC, and for optimizing material design and fabrication processes.

带孔纤维增强复合材料在各个领域有着广泛的应用。本文研究了纤维取向和孔分布对FRC断裂行为的影响。建立相场模型,模拟复合材料的断裂过程,分别对单向纤维增强复合材料和编织纤维增强复合材料的力学性能进行了分析。数值结果表明,纤维取向和孔洞分布对纤维纤维的断裂行为有显著影响。我们观察到,平行于加载方向的纤维排列导致复合材料的最大承载能力增加。孔分布越均匀,FRC的整体力学性能越好。此外,在热冲击存在时,裂纹扩展倾向于向孔方向扩展。这些发现对于理解FRC的断裂行为,优化材料设计和制造工艺具有重要意义。


Structural response of glass fiber-polymer composite bending-active elastica beam under long-term loading conditions

Tara Habibi, Landolf Rhode-Barbarigos, Thomas Keller

doi:10.1016/j.compstruct.2024.118628

长期荷载作用下玻璃纤维-聚合物复合材料主动弯曲弹性梁的结构响应

Bending-active elastica beams represent structural members which are initially installed as straight beams and then bent into arched shapes by applying horizontal displacements to one support. Designing such members for permanent structures made of fiber-polymer composites involves complex viscoelastic responses, which have not yet been thoroughly investigated. An experimental investigation of medium-scale bending-active elastica beams, consisting of pultruded glass fiber-polymer composite profiles, was thus conducted to investigate the long-term structural behavior of such members under imposed sustained bending and axial compression. The results revealed that viscoelastic responses are based on an interaction of stress relaxation and creep with their effects increased with increasing bending degree and time of exposure to sustained strains and stresses. The imposed horizontal displacement to one of the supports to maintain the bent beam shape induced sustained bending stresses in the beam. Beneficial relaxation of these stresses occurred with relaxation predicted to reach 12 % during a targeted 50-year design service life. Furthermore, the likelihood of the curved beam exhibiting in-plane deformations under sustained stresses enabled creep to occur simultaneously, with associated in-plane creep deformations and strength reduction. While creep deformations remained insignificant, progressive creep rupture occurred at highest bending degrees, exhibiting sequential creep rupture in the outer combined mat layers, delamination, crack opening and final fiber failure. Creep rupture can be prevented by postponing crack initiation in the combined mat layer beyond the targeted design service life. This can be achieved by limiting the bending degree to 50 % of the bending degree at which short-term crack initiation occurs.

主动弯曲弹性梁是指最初作为直梁安装的结构构件,然后通过对一个支撑施加水平位移而弯曲成拱形。为由纤维-聚合物复合材料制成的永久性结构设计此类构件涉及复杂的粘弹性响应,这方面的研究尚未深入。因此,对由拉挤玻璃纤维-聚合物复合材料型材组成的中尺度弯曲主动弹性梁进行了实验研究,以研究此类构件在施加持续弯曲和轴向压缩下的长期结构行为。结果表明,粘弹性响应是基于应力松弛和蠕变的相互作用,其影响随着弯曲程度和持续应变和应力暴露时间的增加而增加。施加在其中一个支座上的水平位移以保持弯曲梁的形状,从而在梁中产生持续的弯曲应力。这些应力发生了有益的松弛,在目标50年的设计使用寿命期间,松弛率预计达到12% %。此外,弯曲梁在持续应力下表现出面内变形的可能性使蠕变同时发生,并伴有面内蠕变变形和强度降低。当蠕变不明显时,在最高弯曲度处发生渐进性蠕变断裂,表现为外层复合层的顺序蠕变断裂、分层、开裂和最终纤维破坏。通过将组合垫层中的裂纹起始推迟到目标设计使用寿命之后,可以防止蠕变破裂。这可以通过将弯曲度限制在产生短期裂纹的弯曲度的50% %来实现。


Composites Part A: Applied Science and Manufacturing

Characterization and property prediction of fibre structures within discontinuous-fibre reinforced polymer matrix composites using 3D fibre cells assisted by contrastive learning

Yuheng Zhou, Pascal Hubert

doi:10.1016/j.compositesa.2024.108506

利用对比学习辅助的三维纤维细胞对非连续纤维增强聚合物基复合材料中的纤维结构进行表征和性能预测

Fibre-cell-based fibre structure characterization approach was proposed recently to characterize the fibre distribution within discontinuous-fibre reinforced polymer matrix composites (DFR PMCs) over a 2D domain. This approach determines the distribution state of each fibre based on the relative size and topological features of its fibre cell. In this study, the fibre-cell-based approach is extended for 3D fibre domains. A convolutional neural network (CNN) encoder is trained through contrastive learning to quantitatively represent topological features of 3D fibre cells. Subsequently, the feature-property correlations are established using an artificial neural network (ANN). For practical application, the ANN is integrated with an image analysis software to provide in situ predictions of local elastic modulus of a DFR PMC based on its fibre structures observed from micro-CT images. The predictions are also compared with the experimental measurements acquired through microindentation testing, and it shows a good agreement.

最近提出了一种基于纤维细胞的纤维结构表征方法,用于表征非连续纤维增强聚合物基复合材料(DFR PMCs)内的二维纤维分布。这种方法根据纤维细胞的相对大小和拓扑特征来确定每根纤维的分布状态。在本研究中,基于纤维细胞的方法扩展到三维纤维域。通过对比学习训练卷积神经网络(CNN)编码器,定量表征三维纤维细胞的拓扑特征。随后,使用人工神经网络(ANN)建立特征-属性相关性。在实际应用中,人工神经网络与图像分析软件相结合,根据微ct图像观察到的纤维结构,提供DFR PMC局部弹性模量的原位预测。并将预测结果与微压痕试验结果进行了比较,结果表明预测结果吻合较好。


Design of experiments investigation into the production of all cellulose composites using regenerated cellulosic textiles

Ashley Victoria, Peter John Hine, Keeran Ward, Michael Edward Ries

doi:10.1016/j.compositesa.2024.108510

利用再生纤维纺织品生产全纤维素复合材料的实验设计研究

All cellulose composites (ACCs) can be produced from native and man-made cellulosic fibres; use of the latter provides an additional application for waste-derived regenerated fibers. ACCs were prepared using an ionic liquid dissolution method, utilizing a regenerated cellulose (Tencel) textile, with and without an interleaf cellulosic film. A design of experiments methodology was applied to explore process-property relationships; concentration of the ionic liquid and the processing time and temperature were investigated. It was found that the film remained in-between the textile layers, rather than penetrating the fiber assembly, in contrast to our previous work on cotton-based ACCs. This is due to the structural differences between Tencel and cotton fabric. A multi-response optimization was conducted through a central composite face centered strategy, which captured the film system more strongly. Optimized processing conditions were identified, yielding a Young’s modulus and strain-to-failure of 5.3 GPa and 3.5% respectively,;alidated through in-lab samples.

所有纤维素复合材料(ACCs)都可以由天然和人造纤维素纤维生产;后者的使用为废物衍生的再生纤维提供了额外的应用。采用离子液体溶解法,利用再生纤维素(天丝)织物,有或没有交错的纤维素膜制备acc。采用实验设计方法探索工艺-性能关系;考察了离子液体的浓度、处理时间和温度。我们发现,薄膜仍然在纺织层之间,而不是穿透纤维组件,这与我们之前对棉基ACCs的研究相反。这是由于天丝和棉织物的结构差异。采用中心复合面为中心策略进行多响应优化,更强地捕获了薄膜系统。确定了优化的加工条件,杨氏模量和应变破坏比分别为5.3 GPa和3.5%,并通过实验室样品进行了验证。


Composites Science and Technology

Experimental and numerical validation of high strain rate impact response and progressive damage of 3D orthogonal woven composites

Xue Yang, Dian-sen Li, Xiao-long Jia, Hong-mei Zuo, Lei Jiang, Stepan V. Lomov, Frederik Desplentere

doi:10.1016/j.compscitech.2024.110896

 

三维正交编织复合材料高应变率冲击响应及渐进损伤的实验与数值验证

Advanced three-dimensional (3D) woven composites for aerospace and automotive applications are commonly subjected to complex dynamic environments involving vibrations and impacts, resulting in examining their impact properties is extremely important. This paper first experimentally discussed the influences of strain rates, weft yarn densities and loading directions on the impact performances and failure mechanisms of 3D orthogonal woven composites (3DOWCs). Secondly, full-scale finite element models were developed to predict the stress distribution and interfacial damage evolution process. The predictions were well in agreement with the experimental results. This research revealed that the impact characteristics exhibited strain rate sensitivity. With increasing weft yarn densities, the high strain rate impact behaviors also improved. Particularly, the warp impact strength of 3DOWCs with a weft yarn density of 2 yarn/cm (W5-2) at 812 s-1 was 17.4% and 24.0% higher than that of 3DOWCs with a weft yarn density of 1.5 yarn/cm (W5-1) at 822 s-1. Meanwhile, warp impact strength consistently exceeded to that of the weft impact strength. Additionally, strain rates, weft yarn densities, and loading directions dramatically affected the stress distribution and interfacial damage evolution process of 3DOWCs. Significant warp yarns fracture and matrix cracking were the principal failure patterns in the warp impact, whereas the damage in the weft impact was dominated by localized fracture of weft yarns and interfacial debonding.

用于航空航天和汽车应用的先进三维(3D)编织复合材料通常会受到涉及振动和冲击的复杂动态环境的影响,因此检查其冲击性能非常重要。本文首先通过实验研究了应变率、纬纱密度和加载方向对三维正交编织复合材料(3DOWCs)冲击性能和破坏机理的影响。其次,建立全尺寸有限元模型,预测应力分布和界面损伤演化过程;预测结果与实验结果非常吻合。研究表明,冲击特性具有应变率敏感性。随着纬纱密度的增加,高应变率冲击性能也得到改善。纬纱密度为2支/cm (W5-2)的3DOWCs在812 s-1下的经纱冲击强度比纬纱密度为1.5支/cm (W5-1)的3DOWCs在822 s-1下的经纱冲击强度分别提高了17.4%和24.0%。同时,经纱冲击强度不断超过纬纱冲击强度。应变速率、纬纱密度和加载方向对三维dowcs的应力分布和界面损伤演化过程有显著影响。经纱断裂和基体开裂是经纱冲击的主要破坏形式,纬纱局部断裂和界面脱粘是纬纱冲击的主要破坏形式。


Post Impact Flexural Behavior Investigation of Hybrid Foam-Core Sandwich Composites at Extreme Arctic Temperature

Faizan Mirza, Jason P. Mack, Arnob Banik, M.H. Khan, K.T. Tan

doi:10.1016/j.compscitech.2024.110897

 

极端北极温度下混杂泡沫芯夹层复合材料冲击后弯曲行为研究

This study explores the post-impact bending behavior and failure mechanisms in hybrid sandwich composites made of Carbon Fiber Reinforced Polymer (CFRP) and Glass Fiber Reinforced Polymer (GFRP). Flexural tests conducted at both ambient room temperature and low temperature Arctic conditions reveal a significant enhancement in flexural performance when GFRP layer is incorporated on the outer side of the hybrid composite. The investigation utilizes images from testing to elucidate damage modes, including fiber and matrix cracking in the composite facesheet, as well as core shearing and debonding in the Polyvinyl Chloride (PVC) foam core. Residual flexural properties are notably influenced by stacking sequence, facesheet compressive properties, pre-existing impact damage and temperature conditions. Analytical predictions, validated experimentally, highlight the effect of stacking sequence, low temperature, and impact energy on flexural collapse modes, with competing failure modes such as indentation and core shear. Collapse maps indicate that room temperature specimens predominantly collapse through indentation, while diverse collapse mechanisms emerge due to facesheet thickness, rigidity, and degraded tensile strength. The study aims to provide fundamental insights for future composite designs tailored for Arctic applications.

本研究探讨了碳纤维增强聚合物(CFRP)和玻璃纤维增强聚合物(GFRP)混合夹层复合材料的冲击后弯曲行为和破坏机制。在室温和北极低温条件下进行的弯曲试验表明,在混合复合材料的外侧加入玻璃钢层后,弯曲性能显著增强。该研究利用测试图像来阐明损伤模式,包括复合材料表面的纤维和基体开裂,以及聚氯乙烯(PVC)泡沫芯的剪切和脱粘。残余弯曲性能受堆积顺序、表面压缩性能、预先存在的冲击损伤和温度条件的显著影响。经过实验验证的分析预测强调了堆积顺序、低温和冲击能量对弯曲破坏模式的影响,以及压痕和核心剪切等竞争破坏模式。坍塌图表明,室温试样主要通过压痕坍塌,而由于面板厚度、刚度和抗拉强度下降,出现了多种坍塌机制。该研究旨在为未来针对北极应用量身定制的复合材料设计提供基本见解。


Synergistic enhancement of magic triangle properties of PC tread stocks modified by amine-capped trans-1,4-poly (butadiene-co-isoprene)

Shufang Luo, Kaixuan Dong, Shuo Wang, Aihua He

doi:10.1016/j.compscitech.2024.110899

 

胺包覆反式-1,4-聚丁二烯-co-异戊二烯改性PC胎面胶的魔三角性能协同增强

The development of high-performance “green tires” with synergistically improved “magic triangle” properties like lower rolling resistance, higher wet-skid resistance and higher abrasion resistance has always been a hot issue. In this work, an effective strategy for developing high-performance “green tires” with simultaneously improved “magic triangle” properties of solution-polymerized styrene-butadiene rubber (SSBR)/cis-1,4-polybutadiene rubber (BR) nanocomposites modified by amine-capped trans-1,4-poly(butadiene-co-isoprene) copolymers (F-TBIR) was proposed. A series of F-TBIR with 10-60 mol% amine-capped efficiency (CE) and 30-90×104 weight-average molecular weight (Mw) were synthesized by using heterogeneous TiCl4/MgCl2-Al(i-Bu)3 Ziegler-Natta catalyst with dicyclohexylamine (DCHA) as chain transfer agent (CTA). With the increase in CE of F-TBIR, the silica-filled SSBR/BR/F-TBIR compounds exhibited improved green strength, modulus at 100% elongation and bound rubber, and their vulcanizates showed synergistically improved “magic triangle” properties like obviously reduced rolling resistance and abrasion loss, and increased wet-skid resistance. It was found that the incorporation of 10 phr F-TBIR3 with CE of 60% and Mw of 32×104 resulted in highly expected properties of the SSBR/BR/F-TBIR3 nanocomposite. The contribution mechanism of F-TBIR3 was discussed based on the improvements of polymer network structures and filler network structures. This work is expected to provide an effective strategy to construct the desired network structures for high-performance rubber composites.

高性能“绿色轮胎”在降低滚动阻力、提高湿滑阻力和耐磨性等“魔术三角”性能的协同提升方面,一直是研究的热点问题。本研究提出了一种有效策略,通过使用胺封端的顺式-1,4-聚(丁二烯-共-异戊二烯)共聚物(F-TBIR)改性的溶液聚合苯乙烯-丁二烯橡胶(SSBR)/顺式-1,4-聚丁二烯橡胶(BR)纳米复合材料,来开发高性能的“绿色轮胎”,并实现“魔术三角”性能的同步改善。采用TiCl4/MgCl2-Al(i-Bu)3 Ziegler-Natta催化剂体系,以二环己胺(DCHA)为链转移剂,合成了胺封端效率(CE)为10%-60%、重均分子量(Mw)为30-90×10⁴的系列F-TBIR。随着F-TBIR CE的增加,填充了硅石的SSBR/BR/F-TBIR化合物表现出提高的绿色强度、100%伸长率下的模量和结合橡胶含量,其硫化物表现出协同改善的“魔术三角”性能,包括明显降低的滚动阻力和磨损损失,以及提高的湿滑阻力。研究发现,当引入10份质量比的F-TBIR3(CE为60%,Mw为32×10⁴)时,SSBR/BR/F-TBIR3纳米复合材料表现出理想的性能。基于聚合物网络结构和填料网络结构的改善,讨论了F-TBIR3的贡献机制。本研究有望为构建高性能橡胶复合材料的理想网络结构提供一种有效策略。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform振动断裂复合材料非线性航空航天汽车UG裂纹材料CAPP试验纺织
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【新文速递】2024年9月22日复合材料SCI期刊最新文章

今日更新:Composite Structures 4 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 3 篇,Composites Science and Technology 3 篇Composite StructuresA temperature-sensitive actuator based on AG/NIPAM delignification wood-based hydrogelJiuming Xiong, Ranran Wu, Yufang Hu, Zhiyong Guo, Sui Wang, Jie Maodoi:10.1016/j.compstruct.2024.118580一种基于AG/NIPAM脱木质素木基水凝胶的温度敏感执行器Hydrogels are important in smart drive materials because of their stretchability and biocompatibility. However, challenges in their mechanical properties and preparation process as actuators hinder their potential applications. In this work, a double-layer composite hydrogel actuator was proposed. The actuator consists of two layers of materials, namely delignification wood and agarose (AG)/poly(N-isopropylacrylamide) (PNIPAM) composite hydrogel, named as double-layer wood-based hydrogel (BWH). In BWH, due to the large amount of hydroxyl groups on the surface of delignification wood, abundant hydrogen bonds can be formed with the hydrogel layer to ensure the close adhesion of the two layers and achieve stable synergy. At the same time, the delignification wood can give the overall stable structure and predictable bending direction. In addition, BWH has excellent anti-swelling properties, which is due to the double network design of the hydrogel layer and the anti-swelling properties of the delignification wood skeleton itself. Based on the property of BWH sensitive to temperature deformation, its applications in the field of intelligent grasping and fluid valve were studied. This work provides a simple method for the preparation of response actuators and the idea of mechanical enhancement and adjustable deformation direction.水凝胶因其可拉伸性和生物相容性在智能驱动材料中占有重要地位。然而,它们作为致动器的机械性能和制备工艺方面的挑战阻碍了它们的潜在应用。本文提出了一种双层复合水凝胶致动器。该致动器由两层材料组成,即脱木质素木材和琼脂糖(AG)/聚n -异丙基丙烯酰胺(PNIPAM)复合水凝胶,称为双层木基水凝胶(BWH)。在BWH中,由于脱木质素木材表面有大量的羟基,可以与水凝胶层形成丰富的氢键,保证两层的紧密粘附,实现稳定的协同作用。同时,去木素化木材可以使整体结构稳定,弯曲方向可预测。此外,BWH具有优异的抗膨胀性能,这是由于水凝胶层的双网状设计和脱木质素木骨架本身的抗膨胀性能。基于BWH对温度变形敏感的特性,研究了其在智能抓取和流体阀等领域的应用。该工作为响应驱动器的制备提供了一种简便的方法,并为机械增强和变形方向可调提供了思路。Multiscale study on compressive failure mechanism of plain woven composites considering stochastic waviness defectsJie Sun, Hongneng Cai, Yaping Huang, Erjin Yundoi:10.1016/j.compstruct.2024.118600 考虑随机波纹缺陷的平纹编织复合材料压缩破坏机制的多尺度研究This work proposes a multiscale correlation algorithm based on structural level to study the compression damage behavior of plain woven composites. The multiscale algorithm includes a homogenization process that establishes the mesoscale constitutive relationship based the mechanical properties of microscopic constituent to derive the macro-mechanical response, and a localization process that constructs a mapping relationship among mesoscale stress, microscale stress and micro-component failure based on the macroscale load. The results of uniaxial compression experiments are used to validate the model. The multiscale model combined with micro-mechanics of failure (MMF) and 3D kinking model accurately predict the effective stiffness, ultimate compressive strength, damage modes and fracture characteristics. With increasing compression load, the matrix damage of yarn, fiber kinking and pure matrix damage successively initiate. Furthermore, the effect of yarn waviness defects deviating from the ideal design on compressive mechanical behavior is parametrically investigated based on the hypothesis of Gaussian distribution for defects. The increase of waviness misalignment angle (the difference between actual and ideal waviness angle) and its dispersion degree reduces the compression modulus and failure strength. Therefore, the influence of stochastic waviness defects on mechanical response cannot be ignored in structural level design and application of woven composites.提出了一种基于结构层次的多尺度相关算法来研究平纹编织复合材料的压缩损伤行为。多尺度算法包括基于细观构件力学特性建立细观本构关系的均质化过程和基于宏观荷载建立细观应力、细观应力和细观构件破坏映射关系的局部化过程。用单轴压缩实验结果验证了模型的正确性。结合细观破坏力学(MMF)和三维扭结模型的多尺度模型能准确预测有效刚度、极限抗压强度、损伤模式和断裂特征。随着压缩载荷的增大,纱线基体损伤、纤维扭结和纯基体损伤先后发生。此外,基于缺陷的高斯分布假设,参数化研究了偏离理想设计的纱线波纹度缺陷对纱线压缩力学性能的影响。波浪形失向角(实际与理想波浪形角之差)及其弥散度的增大,降低了材料的抗压模量和破坏强度。因此,在机织复合材料的结构水平设计和应用中,随机波纹缺陷对力学响应的影响是不可忽视的。Shape memory sandwich structure with reprogrammable shape and mechanical propertiesWei Zhao, Chengjun Zeng, Liwu Liu, Jinsong Leng, Yanju Liudoi:10.1016/j.compstruct.2024.118604形状记忆夹芯结构,具有可重新编程的形状和机械性能Sandwich structures are usually used in aerospace and automotive engineering fields. By selecting different core materials and panels, a large number of design strategies are proposed to obtain various types of sandwich structures for various applications. Here, we developed a kind of shape memory sandwich structure using shape memory foam and laminates. The sandwich structure can not only program its shape utilizing SME but also can adjust its mechanical properties by controlling its temperature or shape. The mechanical and thermal–mechanical properties of shape memory laminates, foam and sandwich structure were characterized, respectively. The energy absorption property and bending resistance of the shape memory sandwich structure after being programmed were studied by compression test and drop weight impact test. Shape programmable and mechanical properties adjustable suggest potential applications of this sandwich structure in an adjustable shock-absorbing interface and space deployable structure.夹层结构通常用于航空航天和汽车工程领域。通过选择不同的芯材和面板,提出了大量的设计策略,以获得不同用途的不同类型的夹层结构。在此,我们开发了一种使用形状记忆泡沫和层压板的形状记忆夹层结构。夹层结构不仅可以利用SME对其形状进行编程,还可以通过控制其温度或形状来调节其力学性能。分别对形状记忆层压板、泡沫和夹层结构的力学性能和热力学性能进行了表征。通过压缩试验和落锤冲击试验,研究了编程后形状记忆夹层结构的吸能性能和抗弯性能。形状可编程,机械性能可调,表明该夹层结构在可调减震界面和空间展开结构中的潜在应用。Investigation of the dynamic compression behavior of 3D braided composites based on a virtual fiber embedding methodShengkai Liu, Aoxin Wang, Bicheng Sun, Siqi Liu, Meiqi Hu, Qian Jiang, Liwei Wudoi:10.1016/j.compstruct.2024.118592基于虚拟纤维嵌入法的三维编织复合材料动态压缩性能研究The three-dimensional braided composites (3DBCs) possess a complex spatial structure, which can lead to microscopic deformation of fibers under high-speed impact. This paper proposes a quasi-fiber scale model using virtual fiber-embedded (VFE) method to simulate the impact behavior and failure of 3DBCs. The results reveal that the maximum eccentricity of the VFE model yarn cross-section is 0.318, representing a 194% improvement compared to solid yarns. According to the characteristics of damage, it can be deduced that interactions among fibers play a pivotal role in determining the failure behavior of composites, particularly concerning non-linear changes. The modulus, strength and the time of initial damage rise with an increasing braiding angle, whereas the resin stress, yarn stress, and degree of damage exhibit opposite trends. The stress distribution over the braiding path shows that the main load-bearing component at 20° braiding angles is internal yarns, whereas the surface yarns take precedence at 40°. The maximum deformation of the yarn cross-section always occurs at the center of the shear band, with a maximum eccentricity of 0.456 at 20° braiding angles. The deformation in yarn flexing and cross-section flattening cause an uneven distribution of stress and strain, leading to localized damage and ultimately catastrophic destruction.三维编织复合材料(3DBCs)具有复杂的空间结构,在高速冲击下会导致纤维的微观变形。本文提出了一种基于虚拟光纤嵌入(VFE)方法的准光纤比例模型来模拟3DBCs的冲击行为和失效。结果表明,VFE模型纱线截面的最大偏心为0.318,比实心纱线提高了194%。根据损伤的特点,可以推断出纤维间的相互作用在决定复合材料的破坏行为中起着关键作用,特别是在非线性变化的情况下。模量、强度和初始损伤时间随编织角度的增大而增大,而树脂应力、纱线应力和损伤程度呈相反趋势。在编织路径上的应力分布表明,在编织角度为20°时,主要承重成分是内部纱,而在编织角度为40°时,表面纱占主导地位。纱线截面的最大变形总是发生在剪切带的中心,在编织角为20°时,最大偏心为0.456。纱线在弯曲和横截面压扁过程中的变形导致应力应变分布不均匀,导致局部损伤,最终造成灾难性破坏。Composites Part A: Applied Science and Manufacturing“Dual-purpose” strategy of achieving fire safety and UV-resistance of polylactic acidXinyu Cui, Jinxuan Chen, Weiwen Gu, Jian Liu, Hongfei Li, Xiaoyu Gu, Jun Sun, Sheng Zhangdoi:10.1016/j.compositesa.2024.108485 实现聚乳酸防火安全和抗紫外线的“一箭双飞”策略Flame-retardant properties are crucial for polylactic acid (PLA) used in packaging, electrical, and agricultural applications. However, PLA is susceptible to degradation from ultraviolet (UV) light, limiting its longevity. This necessitates the development of PLA composites with improved flame-retardant and UV-resistant properties. Here, we synthesized a multifunctional core–shell spherical flame-retardant TA@HPDT, employing tannic acid (TA) for its effective free radical trapping capability. TA@HPDT was incorporated into PLA to enhance fire safety and UV resistance. The PLA-2 % TA@HPDT composite exhibited exceptional flame-retardant efficiency, achieving a UL-94 V-0 rating and a limiting oxygen index of 25.6. Furthermore, the addition of TA@HPDT reduced the peak heat release rate and total heat release by 16.8 % and 16.7 %, respectively. After 100 h of UV aging, the PLA composite retained 93.3 % of its mass, indicating significantly improved UV resistance. This study demonstrates a strategic approach to developing PLA composites that enhance fire performance and extend service life.阻燃性能对用于包装、电气和农业应用的聚乳酸(PLA)至关重要。然而,PLA易受紫外线(UV)光的降解,限制了它的寿命。这就需要开发具有改进阻燃和抗紫外线性能的聚乳酸复合材料。在此,我们合成了一种多功能核壳球形阻燃剂TA@HPDT,利用单宁酸(TA)有效的自由基捕获能力。TA@HPDT被纳入PLA,以提高消防安全和抗紫外线能力。PLA-2 % TA@HPDT复合材料表现出优异的阻燃效率,达到UL-94 V-0等级和25.6的极限氧指数。此外,TA@HPDT的加入使峰值放热率和总放热率分别降低了16.8 %和16.7 %。经过100 h的UV老化后,PLA复合材料的质量保留率为93.3 %,抗UV性能显著提高。这项研究展示了一种开发PLA复合材料的战略方法,可以提高防火性能和延长使用寿命。Composites Part B: EngineeringStudy on the fracture behavior and toughening mechanisms of continuous fiber reinforced Wf/Y2O3/W composites fabricated via powder metallurgyRui Shu, Yiran Mao, Alvaro Martinez-Pechero, Jan W. Coenen, Alexis Terra, Stephan Schönen, Johann Riesch, Christian Linsmeier, Christoph Broeckmanndoi:10.1016/j.compositesb.2024.111845粉末冶金连续纤维增强Wf/Y2O3/W复合材料断裂行为及增韧机理研究Tungsten (W) is a promising candidate material for the plasma facing components in fusion reactors. However, it has issues regarding the intrinsic brittleness. Tungsten fiber reinforced tungsten composites (Wf/W) have been developed based on the concept of extrinsic toughening mechanisms and they show a pseudo-ductile behavior during the fracture process. In the present work, continuous fiber reinforced Wf/Y2O3/W composites were fabricated via a powder metallurgy (PM) process, and the microstructure and mechanical properties were characterized. The fracture behavior and toughening mechanisms were analyzed in detail combining the results of experiments and numerical simulation. The Wf/Y2O3/W composites is toughened by multiple mechanisms such as fiber bridging, crack bending and deflection, interface de-bonding and plastic deformation of fiber. The energy dissipation by interface de-bonding can be neglected. However, it is a necessary factor to ensure any extrinsic toughening mechanisms. The main contribution of the energy dissipation while composite failure is the plastic deformation of fibers.钨(W)是一种很有前途的用于聚变反应堆等离子体面组件的候选材料。然而,它存在固有脆性方面的问题。钨纤维增强钨复合材料(Wf/W)是一种基于外在增韧机制的材料,在断裂过程中表现出伪延性。采用粉末冶金(PM)法制备了连续纤维增强Wf/Y2O3/W复合材料,并对其微观组织和力学性能进行了表征。结合实验和数值模拟结果,对其断裂行为和增韧机理进行了详细分析。Wf/Y2O3/W复合材料通过纤维桥接、裂纹弯曲和挠曲、界面脱粘和纤维塑性变形等多种机制增韧。界面脱键的能量耗散可以忽略不计。然而,这是保证任何外在增韧机制的必要因素。复合材料破坏时能量耗散的主要贡献是纤维的塑性变形。Enhancing Flame Retardancy in 3D Printed Polyamide Composites Using Directionally Arranged Recycled Carbon FiberShouao Zhu, Bo Xu, Wei Zhao, Gong Wangdoi:10.1016/j.compositesb.2024.111854 利用定向排列的再生碳纤维增强3D打印聚酰胺复合材料的阻燃性Combining recycled carbon fiber (rCF) and 3D printing technology has shown great potential for fabricating functional prototypes and production parts used in the aerospace and automotive industries. However, it is still a challenge to design flame-retardant 3D printed parts with high mechanical properties and flame-retardant rating. In the work, a flame-retardant polyamide (PA)-based composite for material extrusion 3D printing was prepared by utilization of rCF, polyhedral oligomeric silsesquioxanes (POSS), and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene (DOPO)-based flame retardant. The 3D-printed composites have high thermal stability, mechanical properties, and excellent flame retardancy with a V-0 rating. With the benefits of material extrusion 3D printing, directionally arranged rCF in 3D printed composites could effectively inhibit the fire spread, extend the time to ignition (TTI), reduce the total heat release (THR) and total smoke release (TSR) of 3D printed composites. The directional flame-retardant mechanism is mainly the thermal conductivity mechanism of the condensed phase and the promotion of stable ordered carbon layer formation. It provides a promising path for designing high-performance flame-retardant materials.将再生碳纤维(rCF)与3D打印技术相结合,在制造航空航天和汽车工业中使用的功能原型和生产部件方面显示出巨大的潜力。然而,设计具有高机械性能和阻燃等级的阻燃3D打印部件仍然是一个挑战。本研究利用rCF、多面体低聚硅氧烷(POSS)和9,10-二氢-9-氧-10-磷菲(DOPO)基阻燃剂制备了一种用于材料挤出3D打印的阻燃聚酰胺(PA)基复合材料。3d打印复合材料具有高热稳定性、机械性能和优异的阻燃性,阻燃等级为V-0。利用材料挤压3D打印的优势,3D打印复合材料中定向排列的rCF可以有效地抑制火势蔓延,延长着火时间(TTI),降低3D打印复合材料的总放热(THR)和总放烟(TSR)。定向阻燃机理主要是凝聚相的导热机理和促进稳定有序碳层的形成。这为设计高性能阻燃材料提供了一条很有前途的途径。The role of ettringite seeds in enhancing the ultra-early age strength of Portland cement containing aluminum sulfate acceleratorHaochuan Wang, Pan Feng, Xin Liu, Jiashun Shi, Chong Wang, Wei Wang, Hua Li, Jinxiang Hongdoi:10.1016/j.compositesb.2024.111856 钙矾石种子对含硫酸铝促进剂硅酸盐水泥超早龄期强度的提高作用The ultra-early age strength of shotcrete with Portland cement-based materials in various supporting constructions is crucial for safety and engineering efficiency. However, concerns exist about the low strength and uncertain mechanism when using aluminum sulfate, the main component of most-used alkali-free accelerators. This study addresses these concerns by introducing ettringite seeds into the Portland cement system with aluminum sulfate. Significant improvement in ultra-early age compressive strength of mortar, i.e., 242% at 6 hours and 201% at 8 hours, was achieved by mere 1% seed addition. Analyses of hydration heat, composition and microstructure demonstrate that the ettringite seeds mainly affect the mechanical performance by forming a more prolonged and coarser ettringite skeleton, rather than directly accelerating cement hydration. Such an enhanced skeleton was proved to establish stronger interactions between particles in the Monte Carlo simulations. Additionally, the synergistic effect of the ettringite skeleton and C-S-H gel on ultra-early age strength was also explored. These proposed strengthening mechanisms were verified by the C3S and equivalent CaCO3 systems.硅酸盐水泥基材料喷射混凝土的超早龄期强度对各种支护结构的安全性和工程效率至关重要。然而,使用硫酸铝作为最常用的无碱促进剂的主要成分时,存在强度低和机理不确定的问题。本研究通过将钙矾石种子引入硫酸铝硅酸盐水泥体系来解决这些问题。仅添加1%的种子即可显著提高砂浆的超早期抗压强度,即在6小时时提高242%,在8小时时提高201%。水化热、成分和微观结构分析表明,钙矾石种子对水泥力学性能的影响主要是通过形成更长、更粗的钙矾石骨架,而不是直接加速水泥水化。在蒙特卡洛模拟中,这种增强骨架被证明在粒子之间建立了更强的相互作用。此外,还探讨了钙矾石骨架与C-S-H凝胶对超早龄期强度的协同作用。C3S和等效CaCO3体系验证了上述强化机制。Composites Science and TechnologySelf-assembled nest-like BN skeletons enable polymer composites with high thermal management capacityJiangang Zhou, Congzhen Xie, Huasong Xu, Bin Gou, An Zhong, Daoming Zhang, Hangchuan Cai, Chunhui Bi, Licheng Li, Rui Wangdoi:10.1016/j.compscitech.2024.110869 自组装的巢状BN骨架使聚合物复合材料具有高热管理能力The lagging development of thermally conductive but electrically insulating materials has become a bottleneck problem for the next generation of advanced high-power density electronic devices. Although second-phase reinforced composites are promising materials for addressing thermal management issues, the inherent mechanism of severe phonon scattering at the interphase results in actual thermal conductivity enhancement efficiency far below expectations. Here, we report a high-performance polymer composite with a nest-like interconnected boron nitride skeleton. This nest-like interconnected BN skeleton without mechanical contact can provide high-efficiency and long-distance phonon transport channel, realizing high thermal conductivity of 1.827 W m-1 K-1 in polymer composite with ultra-low content (4.7 vol%). Meanwhile, the EP/ nest-like BS composites possess ideal electrical properties and dimensional stability. In the actual heat dissipation process of LED chips, the optimal composite material as the thermal interface material can display a temperature drop of more than 34.8% compared to neat epoxy, which proves the broad application prospects of this strategy in advanced electronic devices.导热绝缘材料发展滞后已成为制约下一代先进高功率密度电子器件发展的瓶颈问题。虽然第二相增强复合材料是解决热管理问题的有前途的材料,但其固有的严重声子散射机制导致实际的导热增强效率远低于预期。在这里,我们报道了一种具有巢状互连氮化硼骨架的高性能聚合物复合材料。这种无机械接触的巢状互联BN骨架可提供高效、长距离的声子输运通道,在超低含量(4.7 vol%)的聚合物复合材料中实现1.827 W m-1 K-1的高导热系数。同时,EP/巢状BS复合材料具有理想的电学性能和尺寸稳定性。在LED芯片的实际散热过程中,最优的复合材料作为热界面材料,与纯环氧树脂相比,可以显示出超过34.8%的温度下降,这证明了该策略在先进电子器件中的广泛应用前景。Lightweight composites derived from carbonized taro stems for microwave energy attenuation and thermal energy storageTian Yang, Qing Qi, Li Ma, Tian Li, Jiatong Li, Qian Yang, Fanbin Mengdoi:10.1016/j.compscitech.2024.110874 由碳化芋头茎制成的微波能量衰减和热能储存的轻质复合材料A novel strategy has been developed for preparing porous carbon materials derived from taro stems, aimed at enhancing electromagnetic wave (EMW) attenuation and thermal energy storage. The materials were synthesized through the carbonization of taro stems to form a porous carbon structure, subsequently enhanced with polyethylene glycol (PEG) containing carbon nanotubes (CNTs) and nickel (Ni) nanoparticles. By adjusting the carbonization temperature and the loading of CNTs and Ni, the resulting carbon materials exhibited exceptional EMW attenuation performance. Specifically, the PC-800 sample demonstrated a remarkable minimum reflection loss of −61.4 dB across the frequency range of 8.2 to 11 GHz, with a low density of 0.054 g/cm³. The PC-1200 sample exhibited EMI SE values of 23.6 dB axially and 21.5 dB radially in the X-band, with an ultra-low density of 0.033 g/cm³. Further enhancements were observed in the PC/CNT2 and PC/CNT2-Ni15 composites, achieving EMI SE values of 26.3 dB and 26.8 dB, respectively. Additionally, these composites exhibited effective thermal energy storage and release, as confirmed by heating experiments. This study not only introduces a method for creating absorption-dominated biomass electromagnetic shielding materials but also provides a dual-functional solution for enhancing the performance of electronic devices.以芋头茎为原料制备多孔碳材料,以增强电磁波衰减和热能储存能力。该材料通过对芋头茎进行碳化制备,形成多孔碳结构,随后用含碳纳米管(CNTs)和镍(Ni)纳米颗粒的聚乙二醇(PEG)增强。通过调整炭化温度和碳纳米管和Ni的负载,得到的碳材料表现出优异的EMW衰减性能。具体而言,PC-800样品在8.2至11 GHz的频率范围内显示出- 61.4 dB的最小反射损耗,密度低至0.054 g/cm³。PC-1200样品在x波段的EMI SE值为轴向23.6 dB,径向21.5 dB,超低密度为0.033 g/cm³。PC/CNT2和PC/CNT2- ni15复合材料的EMI SE值进一步增强,分别达到26.3 dB和26.8 dB。此外,加热实验证实,这些复合材料表现出有效的热能储存和释放。本研究不仅介绍了一种以吸收为主的生物质电磁屏蔽材料的制备方法,而且为提高电子器件的性能提供了一种双功能解决方案。A Multifunctional Leather Composite with Good Antibacterial and Hygrothermal Management CapabilitiesPing Wang, Caiqing Mo, Yanqing Liu, Ying Jiang, Zhicheng Zhang, Huajun Wu, Guiyu Luo, Yu She, En-Tang Kang, Kai Zhang, Liqun Xudoi:10.1016/j.compscitech.2024.110875 一种具有良好抗菌和热湿管理能力的多功能皮革复合材料If not removed in a timely manner, the large amount of sweat produced by overheated human skin can cause thermal discomfort and health problems. Development of fabrics with cooling and dehumidifying capabilities is advantageous to improving the quality of human life. In this work, a natural leather-based Zn-monoethanolamine@lignin (Zn-MEA@lignin-leather) composite fabric with personal hygrothermal management properties was fabricated by infiltrating the permeable 3D network microstructure of the natural leather collagen fiber bundles with adhering moisture-absorbent hydrogel containing photothermal lignin. Due to the efficiency of the composite hydrogel in trapping water molecules, the fabric can promote evaporation of sweat from overheated skin surfaces. Compared to the conventional textiles, the composite leather fabric can reduce the humidity of simulated skin surface by about 40% and accelerate the evaporation of sweat from the skin surface to promote reduction in temperature of the overheated body. Thanks to the good photothermal conversion efficiency of lignin, the hydrated composite fabric exhibits a favorable evaporation regeneration rate (0.498 kg m-2 h-1). In addition, the presence of zinc ions in the coordination complex imparts good antimicrobial efficiency to the composite fabric, with inactivation rates approaching 99.99% for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Thus, the composite leather fabric holds great promise to personal hygrothermal management and healthcare.如果不及时清除,人体皮肤过热产生的大量汗液会引起热不适和健康问题。开发具有冷却和除湿功能的织物有利于提高人类的生活质量。在这项工作中,通过将含有光热木质素的粘接吸水水凝胶渗透到天然皮革胶原纤维束的可渗透3D网络微观结构中,制备了具有个人湿热管理性能的天然皮革基Zn-monoethanolamine@lignin (Zn-MEA@lignin-leather)复合织物。由于复合水凝胶捕获水分子的效率,这种织物可以促进汗液从过热的皮肤表面蒸发。与传统纺织品相比,复合皮革织物可使模拟皮肤表面的湿度降低约40%,并加速皮肤表面汗液的蒸发,促进过热身体温度的降低。由于木质素良好的光热转换效率,水合复合织物具有良好的蒸发再生速率(0.498 kg m-2 h-1)。此外,配合物中锌离子的存在使复合织物具有良好的抗菌效率,对金黄色葡萄球菌(S. aureus)和大肠杆菌(E. coli)的灭活率均接近99.99%。因此,复合皮革织物在个人湿热管理和医疗保健方面具有很大的前景。来源:复合材料力学仿真Composites FEM

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