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【新文速递】2023年10月28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 1 篇,Composites Part B: Engineering 5 篇,Composites Science and Technology 1 篇

Composite Structures

Damage Onset Mechanisms in Multi-axial Tensile test of 3D Woven Organic Matrix Composite through an in situ coupled micro-Computed Tomography and Acoustic Emission Methodology

Orenes Balaciart Salvador, Pannier Yannick, Gigliotti Marco, Mellier David, Tranquart Bastien

doi:10.1016/j.compstruct.2023.117651

通过原位微计算机断层扫描和声发射耦合方法研究三维编织有机基复合材料多轴拉伸试验中的损伤发生机制

The present work studies the multi-axial damage onset mechanisms of 3D Woven Organic composite for aero-engine applications. For this purpose, an experimental methodology has been developed to detect the onset of damage by interrupting a tensile test. In situ observations have been performed through micro-Computed Tomography coupled with Acoustic Emission. The synergy between both experimental techniques relates the tomographic observable damage with the released acoustic energy levels succeeding in interrupting the tensile test at the damage initiation. The use of tomography has allowed a visual classification of the damage with respect to the meso-structure of the textile. Further, thanks to this methodology and by carrying out tests in different orientations of the textile and through the use of a Finite Element model at the homogeneous equivalent scale it is possible to identify the failure surface for the first damage of the material.

本研究对用于航空发动机的三维有机编织复合材料的多轴向损伤发生机制进行了研究。为此,我们开发了一种实验方法,通过中断拉伸试验来检测损伤的发生。通过微型计算机断层扫描和声发射技术进行原位观测。这两种实验技术的协同作用将断层扫描观察到的损伤与释放的声能级联系起来,从而成功地在损伤开始时中断拉伸试验。通过使用层析成像技术,可以对纺织品中层结构的损伤进行直观分类。此外,由于采用了这种方法,并通过在织物的不同方向上进行测试,以及通过使用均质等效尺度的有限元模型,可以确定材料首次损坏的破坏面。


Composites Part A: Applied Science and Manufacturing

Hydrogen permeability of thin-ply composites after mechanical loading

Katsivalis Ioannis, Signorini Virginia, Ohlsson Fredrik, Langhammer Cristoph, Minelli Matteo, Asp Leif E.

doi:10.1016/j.compositesa.2023.107867

机械加载后薄层复合材料的透氢率

Hydrogen is a sustainable alternative to conventional fuels, and it may be obtained with near zero carbon footprint. However, hydrogen storage remains a key challenge, and the use of composite tanks has gained significant interest over the last few years. In addition, thin-ply composites promote fibre damage by delaying matrix microcracking and free edge delamination. In this work, the H2 permeation/diffusion performance of virgin and mechanically loaded thin cross-ply laminates is studied. In addition, Scanning Electron Microscopy (SEM) is used to identify defects and micro-damage in the laminates and explain the experimental values. The study shows that the hydrogen (H2) barrier performances of thin-ply composites are lower than conventional metallic systems. Obtained permeability values, however, resulted well below the allowable limits for most combinations of temperature and pressure and remain unaffected despite the application of high tensile strains showing that permeation is not accelerated.

氢气是传统燃料的一种可持续替代品,其获取过程中的碳足迹几乎为零。然而,氢气储存仍然是一项关键挑战,在过去几年中,复合材料储氢罐的使用引起了人们的极大兴趣。此外,薄层复合材料通过延迟基体微裂纹和自由边缘分层来促进纤维损伤。在这项工作中,研究了原生和机械加载薄交叉层压板的 H2 渗透/扩散性能。此外,还使用扫描电子显微镜(SEM)来识别层压板中的缺陷和微损伤,并解释实验值。研究表明,薄层复合材料的氢气(H2)阻隔性能低于传统的金属系统。然而,在大多数温度和压力组合下,所获得的渗透值远低于允许极限值,并且在施加高拉伸应变后仍不受影响,这表明渗透并未加速。


Composites Part B: Engineering

The formation mechanisms and mechanical effects of lattice defects in carbon nanotube reinforced 2024Al composite

Yan Jun, Zhang Cunsheng, Liu Zhenyu, Meng Zijie, Chen Liang, Mu Yue, Zhao Guoqun

doi:10.1016/j.compositesb.2023.111077

碳纳米管增强 2024Al 复合材料晶格缺陷的形成机理与力学效应

Lattice defects significantly affect the mechanical performance of metallic materials. In this study, lattice defects of a carbon nanotube reinforced 2024 aluminum alloy (CNT/2024Al) composite were systematically investigated and the contribution of carbon nanotubes was illustrated. The results showed that dislocations and grain boundaries were closely related to the deformation behavior and lead to discontinuous yielding phenomena. Moreover, the carbon nanotubes reduced the stacking fault energy, which was conducive to forming stacking faults and a small number of twins in the composite. The stacking faults, twin boundaries, and intragranular Al4C3 phases hindered dislocation motion, thus enhancing the mechanical properties of the composite. In addition, the novel formation mechanism of the 9R structure was revealed: the Σ3(111)/(151) incoherent twin boundary may dissociate into two tilt walls bounding a 9R structure (zone axis:[101]), which enriches understanding of the relationship between Σ3 twin boundaries and the 9R structure.

晶格缺陷会严重影响金属材料的机械性能。本研究对碳纳米管增强 2024 铝合金(CNT/2024Al)复合材料的晶格缺陷进行了系统研究,并说明了碳纳米管的贡献。结果表明,位错和晶界与变形行为密切相关,并导致不连续屈服现象。此外,碳纳米管降低了堆叠断层能量,有利于在复合材料中形成堆叠断层和少量孪晶。堆叠断层、孪晶边界和粒内 Al4C3 相阻碍了位错运动,从而提高了复合材料的机械性能。此外,研究还揭示了 9R 结构的新形成机制:Σ3(111)/(151) 非相干孪晶边界可能解离成两个倾斜壁,形成 9R 结构(区轴:[101]),从而丰富了对Σ3孪晶边界与 9R 结构之间关系的理解。


Strain rate and temperature dependence of short/unidirectional carbon fibre PEEK hybrid composites

Pheysey James, De Cola Francesco, Pellegrino Antonio, Martinez-Hergueta Francisca

doi:10.1016/j.compositesb.2023.111080

短纤维/单向碳纤维 PEEK 混合复合材料的应变速率和温度依赖性

Short fibre and hybrid carbon fibre PEEK composite materials were tested in tension and compression under quasi-static and high strain rate conditions to observe the strain rate dependence. Multiple temperatures including room temperature, +85 and −50 °C were used to investigate the temperature dependence of the materials. The hybrid laminate comprised a consolidated short fibre core reinforced with outer UD plies in the 0°orientation to provide maximum reinforcement whilst minimising the quantity of expensive UD composite used. Under compression, the beneficial effect of the hybridisation strategy was observed for all high-strain rate testing conditions, where the hybrid laminate outperformed the response of the individual constituents in terms of strength and strain rate dependency. The outer unidirectional (UD) layers contributed to confining the short fibre core, providing superior structural integrity. Under tension, the response was dominated by the UD layers with a 288% increase in strength at room temperature over the short fibre material. However, in the high temperature quasi-static case, the strength was dramatically reduced, by 64%, due to the debonding of the UD reinforcement. This study shows the suitability of hybrid composites for impulsive applications and provides material parameters for the future design of composite structures subjected to impact events.

在准静态和高应变率条件下,对短纤维和混合碳纤维 PEEK 复合材料进行了拉伸和压缩测试,以观察其应变率依赖性。在室温、+85 °C和-50 °C等多个温度下,研究了材料的温度依赖性。混合层压材料包括一个以 0° 方向的 UD 外层加固的短纤维芯材,以提供最大的加固效果,同时最大限度地减少昂贵的 UD 复合材料的用量。在压缩条件下,在所有高应变率测试条件下都能观察到混合策略的有益效果,混合层压材料在强度和应变率相关性方面都优于单个成分的响应。外层单向(UD)层有助于限制短纤维核心,从而提供出色的结构完整性。在拉伸条件下,UD 层的反应占主导地位,室温下的强度比短纤维材料提高了 288%。然而,在高温准静态情况下,由于 UD 加固层的脱粘,强度大幅降低了 64%。这项研究表明了混合复合材料在冲击应用中的适用性,并为今后设计受冲击事件影响的复合材料结构提供了材料参数。


Hydration and strength development in magnesium oxysulfate (MOS) cement incorporating silicic acid

Zhang Tingting, Zhang Jingbin, Chang Jun, Bi Wanli, Cheeseman Chris, Chen Xiaoyang

doi:10.1016/j.compositesb.2023.111081

掺入硅酸的硫酸镁(MOS)水泥的水化和强度发展

The effect of silicic acid (SA) on the hydration and strength development of magnesium oxysulfate (MOS) cement containing citric acid (CA) was reported. Changes to the setting time, hydration reactions, mechanical strength, phase composition, microstructure and pore structure were investigated. The presence of SA promoted the formation of Mg(OH)2·MgSO4·5H2O and 5 Mg(OH)2·MgSO4·7H2O (phase 517), increasing the hydration rate and reducing the setting time of MOS cement containing CA. Magnesium silicate hydrate (MSH) gel with a silicate layered structure was formed after adding SA to MOS cement containing CA, and there was good co-existence between layered MSH gel and phase 517 whisker, which increased the compactness of MOS cement. Results show that the presence of SA enhanced the early mechanical strength of MOS cement by increasing the content and crystallite size of phase 517 whisker, while enhanced the later one by promoting the formation of MSH gel.

报告了硅酸(SA)对含柠檬酸(CA)的硫酸镁(MOS)水泥的水化和强度发展的影响。研究了凝结时间、水化反应、机械强度、相组成、微观结构和孔隙结构的变化。SA 的存在促进了 Mg(OH)2-MgSO4-5H2O 和 5 Mg(OH)2-MgSO4-7H2O(相 517)的形成,提高了含 CA 的 MOS 水泥的水化速率并缩短了凝结时间。在含 CA 的 MOS 水泥中添加 SA 后,形成了具有硅酸盐层状结构的水合硅酸镁(MSH)凝胶,层状 MSH 凝胶与相 517 晶须共存良好,增加了 MOS 水泥的密实度。结果表明,SA 的存在通过增加 517 相晶须的含量和结晶尺寸提高了 MOS 水泥的早期机械强度,同时通过促进 MSH 凝胶的形成提高了后期机械强度。


Contribution made by double-sized TiC particles addition to the ductility–strength synergy in wire and arc additively manufactured Al–Cu alloys

Jin Peng, Zhou Junjie, Zhou Junxiong, Liu Yibo, Sun Qingjie

doi:10.1016/j.compositesb.2023.111078

双尺寸 TiC 粒子的添加对线材和电弧添加制造铝铜合金的延展性-强度协同效应的贡献

An Al–Cu matrix composite reinforced with uniformly-distributed micron- and nano-double-sized TiC particles (MNDS-TiCps) was successfully fabricated using a wire and arc additive manufacturing (WAAM) process. The combined effect of the MNDS-TiCps on the precipitation of the θ″ phase, the structural evolution of the grain boundaries, and solidification dynamics of the deposited Al–Cu matrix composites were subsequently investigated. The micron-sized TiC particles in the molten pool generate nucleation undercooling (ΔT nu, ∼0.32 K) which inhibits grain boundary segregation due to constitutional undercooling and promotes the redistribution of the Cu solute in the Al matrix. The phase composition at the grain boundaries changes from θ-Al2Cu to α-Al + θ-Al2Cu and the non-coherent interface between the α+θ transition zone and θ grain boundary is transformed into a coherent interface between the α+θ grain boundary and Al matrix, i.e. (211)θ-Al2Cu//(111)Al. The decrease in free energy within the Al matrix provides energy to facilitate the growth of nuclei on the surface of the nano-sized particles. A semi-coherent interface is thus detected between the TiC and precipitates, characterized by a crystal orientation relationship of (200)TiC//(310)θ″-Al2Cu. The dislocations that provide pipe-diffusion paths for solute Cu constitute a driving force that coarsens the precipitates, promoting the precipitation of θ″ precipitates. Multi-site co-deformation combined with dislocation increment inhibits stress damage to the micro-interface. The strength and elongation increase by 51.0 % and 118 %, respectively, compared to specimens without TiC. This work provides a novel perspective for tailoring WAAM-deposited Al–Cu alloys by achieving favorable structural evolution in the grain boundaries, inducing the precipitation of precipitates, and yielding outstanding synergy between ductility and strength.

利用线弧增材制造(WAAM)工艺,成功制造出了用均匀分布的微米级和纳米级双尺寸 TiC 粒子(MNDS-TiCps)增强的铝铜基体复合材料。随后研究了 MNDS-TiCps 对θ″相析出、晶界结构演变和沉积铝铜基体复合材料凝固动态的综合影响。熔池中的微米级 TiC 粒子在过冷时产生成核(ΔT nu, ∼0.32 K),从而抑制了由于制宪过冷而导致的晶界偏析,并促进了铝基体中铜溶质的重新分布。晶界处的相组成由 θ-Al2Cu 变为 α-Al + θ-Al2Cu,α+θ 过渡区与θ 晶界之间的非相干界面转变为 α+θ 晶界与铝基体之间的相干界面,即 (211)θ-Al2Cu//(111)Al。铝基体内部自由能的降低为促进纳米级颗粒表面原子核的生长提供了能量。因此在 TiC 和沉淀物之间发现了一个半相干界面,其特征是晶体取向关系为 (200)TiC//(310)θ″-Al2Cu。为溶质 Cu 提供管道扩散路径的位错构成了使沉淀粗化的驱动力,促进了 θ″ 沉淀的析出。多点共变形与位错增量相结合,抑制了微界面的应力破坏。与不含 TiC 的试样相比,强度和伸长率分别提高了 51.0% 和 118%。这项研究为定制 WAAM 沉积铝铜合金提供了一个新的视角,即在晶界中实现有利的结构演变,诱导析出物沉淀,并在延展性和强度之间产生出色的协同效应。


Mechanical strengths and optical properties of translucent concrete manufactured by mortar-extrusion 3D printing with polymethyl methacrylate (PMMA) fibers

Lyu Qifeng, Dai Pengfei, Chen Anguo

doi:10.1016/j.compositesb.2023.111079

用聚甲基丙烯酸甲酯(PMMA)纤维通过砂浆挤压三维打印技术制造的半透明混凝土的机械强度和光学性能

Manufacturing conventional translucent concrete consumes lots of labors and formworks. To solve this problem, novel translucent concrete was proposed and manufactured in this work by mortar-extrusion 3D printing, which used polymethyl methacrylate (PMMA) fibers to transmit light and also reinforce the printed concrete. The printing procedures started by extruding one-layer mortar first, and then the fibers were placed on top the printed mortar. Afterward, repeated the above two steps multiple times. The printability, mechanical strengths, optical properties and micro characteristics of the printed translucent concrete were tested. Results showed the fibers increased the buildability and anisotropy of the printed specimens. Specifically, in comparison with the printed specimens without fibers, the flexural strengths of the printed translucent concrete with fibers increased when loading perpendicular to the fiber orientation, whereas those in other loading directions decreased. The fibers also increased the compressive strengths of the printed specimens when loading perpendicular to the fiber orientation, but decreased those in loading parallel to the fiber orientation. Light transmittance of the fibers in the printed translucent concrete was also studied. Results showed reflection coefficients of concrete, fiber diameters, light incident angles influenced the light transmittance. Generally, the light transmittance increased with the reflection coefficients and fiber diameters but decreased with the light incident angles. And the incident angles, which were affected by the printing quality, influenced the light transmittance more than other two factors did. The results and methods in this work can help to increase the efficiency of manufacturing translucent concrete.

制造传统的半透明混凝土需要消耗大量人力和模板。为了解决这个问题,这项研究提出了新型半透明混凝土,并通过砂浆挤出三维打印技术制造了这种混凝土,该技术使用聚甲基丙烯酸甲酯(PMMA)纤维来透光并加固打印出的混凝土。打印过程中,首先挤出一层砂浆,然后在打印出的砂浆上放置纤维。之后,重复上述两个步骤多次。测试了印刷半透明混凝土的可印刷性、机械强度、光学性能和微观特性。结果表明,纤维提高了印刷试样的可施工性和各向异性。具体来说,与不含纤维的印刷试样相比,含纤维的印刷半透明混凝土在垂直于纤维方向加载时的抗折强度增加,而在其他加载方向的抗折强度降低。纤维还提高了印刷试样在垂直于纤维方向加载时的抗压强度,但降低了平行于纤维方向加载时的抗压强度。还研究了印刷半透明混凝土中纤维的透光率。结果表明,混凝土的反射系数、纤维直径、光线入射角都会影响透光率。一般来说,透光率随反射系数和纤维直径的增加而增加,但随光线入射角度的增加而减少。而入射角受印刷质量的影响比其他两个因素对透光率的影响更大。这项研究的结果和方法有助于提高半透明混凝土的生产效率。


Composites Science and Technology

Influence of realistic microscopic fiber misalignments on compressive damage mechanisms of 3D angle-interlock woven composites: In-situ measurements and numerical simulations

Wang Xiaoyu, Zheng Tao, Li Zhixing, Guo Licheng

doi:10.1016/j.compscitech.2023.110317

逼真的微观纤维错位对三维角交错编织复合材料压缩损伤机制的影响:现场测量和数值模拟

Stochastic fiber misalignments have been proven to have a significant impact on the compressive strength of traditional unidirectional laminates. However, these inherent manufacturing defects are rarely considered when dealing with 3D woven composites, due to the difficulty in characterizing the misalignment angles of individual fibers within all yarns. The current work provides the first in-situ measurements of fiber misalignments in 3D angle-interlock woven composites (3DAWCs) at the microscale, where the continuous fibers inside the warp, weft, and binder yarns are systematically examined using a high-resolution optical microscope. Statistical analysis reveals that the microscopic fiber misalignments follow a normal distribution, and the magnitude of the misalignment angle increases slightly with the degree of yarn fluctuation. Through a developed user subroutine, SDVINI, the obtained misalignment distributions are initialized in the corresponding yarns that belong to the constructed high-fidelity model. In comparison to the idealized one, the model introducing realistic fiber misalignments can effectively correct the overestimated predictions, and exhibits better agreement with the performed experiments. Furthermore, the influence of fiber misalignments on compressive damage mechanisms, particularly kinking failure, is also parametrically studied by incorporating different misalignment distributions.

随机纤维错位已被证明会对传统单向层压板的抗压强度产生重大影响。然而,在处理三维编织复合材料时,由于难以表征所有纱线中单根纤维的错位角,因此很少考虑这些固有的制造缺陷。目前的研究首次在微观尺度上对三维角交错编织复合材料(3DAWC)中的纤维错位进行了原位测量,使用高分辨率光学显微镜对经纱、纬纱和粘合剂纱内的连续纤维进行了系统检测。统计分析表明,微观纤维错位遵循正态分布,错位角的大小随着纱线波动程度的增加而略有增加。通过开发的用户子程序 SDVINI,得到的错位分布被初始化到属于所构建的高保真模型的相应纱线中。与理想化模型相比,引入真实纤维错位的模型能有效修正高估的预测值,并与实验结果表现出更好的一致性。此外,通过引入不同的错位分布,还从参数角度研究了纤维错位对压缩破坏机制的影响,尤其是扭结破坏。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalSystem复合材料光学航空电子增材裂纹材料试验纺织管道
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【新文速递】2023年10月30日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Science and Technology 2 篇Composite StructuresInvestigating the Effect of Cure Schedules and Cure Initiators on Sustainable Composites for Large Offshore StructuresPothnis J.R., Vélon K., Bhatia G.S., Hejjaji A., Comer A.J.doi:10.1016/j.compstruct.2023.117648 研究固化时间表和固化引发剂对大型近海结构可持续复合材料的影响This study evaluates the effect of post-cure schedules and cure initiator form on the mechanical properties of Glass fibre reinforced polymer (GFRP) laminates manufactured using an infusible reactive thermoplastic resin. Tensile, flexural, shear and dynamic mechanical analysis tests were conducted. Fractography was also performed. Specimens fabricated using liquid cure initiator and subjected to an elevated temperature post-cure were the control specimens. Ambient cured specimens decreased by no more than 12% in the case of tensile properties (modulus of 90° specimens) and by < 14.3% in the case of flexural properties (also modulus in 90° specimens). Furthermore, the difference in mechanical properties of 0° specimens fabricated using a powder cure initiator was observed to be within ≈ 7% of respective properties of control specimens. In the context of fabricating thick laminates for large-size offshore structures, the results suggest that an extended ambient post-cure cycle in conjunction with an initiator in powder form can be employed instead of an elevated temperature post-cure schedule with initiator in liquid form. This is economically beneficial since it eliminates infrastructure required for elevated temperature curing/post-curing. The risk of porosity induced due to liquid-based initiators is also avoided.本研究评估了后固化时间和固化引发剂形式对使用可浸润反应性热塑性树脂制造的玻璃纤维增强聚合物(GFRP)层压板机械性能的影响。研究进行了拉伸、弯曲、剪切和动态机械分析测试。此外,还进行了碎裂分析。使用液态固化引发剂制造的试样和固化后的高温试样为对照试样。常温固化试样的拉伸性能(90° 试样的模量)下降不超过 12%,弯曲性能(90° 试样的模量)下降小于 14.3%。此外,还观察到使用粉末固化引发剂制作的 0° 试样的机械性能与对照试样各自性能的差异在 ≈ 7% 以内。结果表明,在为大型海上结构制造厚层压板时,可以采用延长的环境后固化周期和粉末状引发剂,而不是采用液态引发剂的高温后固化计划。这在经济上是有利的,因为它省去了高温固化/后固化所需的基础设施。此外,还可避免液态引发剂引起的气孔风险。The effect of load concentration on one-way response of 3D-woven sandwich panelsMirsalehi Maryam, Kianpour Kiarash, Shahbeyk Sharif, Bakhshi Mohammaddoi:10.1016/j.compstruct.2023.117659荷载集中对三维编织夹芯板单向响应的影响As a relatively new class of load bearing elements, 3D-woven sandwich panels (3DWSPs) are emerging in many engineering applications. Similar to other structural elements, the practical usage of the 3DWSPs requires deep understanding around their mechanical properties like elastic stiffness and failure strength. The present study investigates the effect of load concentration on one-way response of the 3DWSPs by: (1) running a comprehensive set of 64 tests to find out the influence of various interfering parameters such as loading span length, the thickness of loaded skin, the shape of loading bar, and panel’s direction, (2) thoughtful interpretation of the elastic and failure results, (3) generation of failure maps, and (4) development of reliable theoretical models for the linear elastic response and the four observed failure mechanisms of skin indentation, skin wrinkling, core shear collapse, and interpillar skin buckling.作为一类相对较新的承重元件,三维编织夹芯板(3DWSP)正在许多工程应用中崭露头角。与其他结构元件类似,3DWSP 的实际应用需要深入了解其机械特性,如弹性刚度和破坏强度。本研究通过以下方法研究荷载集中对 3DWSP 单向响应的影响:(1)进行 64 项综合测试,以找出加载跨度长度、加载表皮厚度、加载杆形状和面板方向等各种干扰参数的影响;(2)对弹性和破坏结果进行周到的解释;(3)生成破坏图;(4)为线性弹性响应以及表皮压痕、表皮起皱、核心剪切塌陷和柱间表皮屈曲这四种观察到的破坏机制建立可靠的理论模型。Application of Elastic Metamaterials/Meta-structures in Civil Engineering: A ReviewContreras Nicolás, Zhang Xihong, Hao Hong, Hernández Franciscodoi:10.1016/j.compstruct.2023.117663弹性超材料/超结构在土木工程中的应用:综述Inspired by sonic engineering, locally resonant metamaterials have attracted much attention from researchers in civil engineering for their unique characteristics of stress wave attenuation and vibration control capacities. This paper presents a comprehensive review of the latest progress of locally resonant metamaterials and their potential applications in civil engineering for structure protection against dynamic loads. The concepts of metamaterials for stress wave attenuation are introduced first, followed by a comprehensive overview of the historical origins and development of metamaterials. Existing analytical approaches for metamaterials, including theoretical solutions, numerical simulations, and experimental examinations, are summarised. Commonly used meta-structures with internal or external resonators and their applications are reviewed and discussed. Research gaps and future outlooks are also identified and briefed.受声波工程学的启发,局部谐振超材料因其独特的应力波衰减特性和振动控制能力而备受土木工程研究人员的关注。本文全面综述了局部谐振超材料的最新进展及其在土木工程中用于动态载荷结构保护的潜在应用。首先介绍了用于应力波衰减的超材料概念,然后全面概述了超材料的历史起源和发展。总结了现有的超材料分析方法,包括理论求解、数值模拟和实验检验。回顾并讨论了带有内部或外部谐振器的常用超材料结构及其应用。此外,还确定并简要介绍了研究差距和未来展望。Composites Science and TechnologyA new integrated modeling method for predicting low-velocity impact behavior and residual tensile failure of Z-pinned T-jointsZhou Jianwu, Zhao Zhibin, Jia Liyong, Zhang Chaodoi:10.1016/j.compscitech.2023.110316 预测 Z 销 T 型接头低速冲击行为和残余拉伸失效的新型综合建模方法Composite T-joints are highly susceptible to low-velocity impact, which can significantly affect their residual performance due to the primary working condition of bearing out-of-plane tensile loads. Currently, most methods that employ multiple models or analytical steps to sequentially assess the mechanical properties of composites generally exhibit certain limitations, leaving room for improvement. This study has developed a finite element (FE) model to simulate the low-velocity impact and post-impact tensile behaviors of carbon fiber reinforced polymers (CFRP) T-joints using an integrated analysis method. The model is based on stress failure criteria and continuous stiffness degradation theory and incorporates corrections to the damage variables. Both the low-velocity impact and quasi-static tensile portions of the model are implemented using an explicit solver with the VUMAT subroutine for calculations in Abaqus. The element damage states are transferred between the two models via a Python script, mitigating the inefficiencies and uncontrollable errors associated with the traditional method of transferring element information between multiple models or analytical steps. Finally, the numerical results of mechanical response and damage states are compared with experimental findings from various perspectives, and the bridging mechanism of Z-pins is thoroughly investigated. The results show that the model exhibits a maximum error of 10.41 % in the main key parameters during low-velocity impact and a maximum error of 10.30 % in the ultimate load during post-impact tension. The model's delamination damage state and final tensile failure mode closely align with the experimental results. Furthermore, a comprehensive analysis of the FE model indicates that the pull-out force of the Z-pin is unrelated to its implantation position or pull-out rate, and the reinforcing effect of the Z-pin becomes significantly apparent only after the CFRP T-joint reaches a certain degree of initial damage.复合材料 T 型接头极易受到低速冲击,由于其主要工作条件是承受平面外拉伸载荷,这可能会严重影响其剩余性能。目前,大多数采用多种模型或分析步骤依次评估复合材料机械性能的方法普遍存在一定的局限性,有待改进。本研究开发了一种有限元(FE)模型,利用综合分析方法模拟碳纤维增强聚合物(CFRP)T 型接头的低速冲击和冲击后拉伸行为。该模型基于应力失效标准和连续刚度退化理论,并结合了对损伤变量的修正。该模型的低速冲击和准静态拉伸部分均采用显式求解器和 VUMAT 子程序在 Abaqus 中进行计算。元素损伤状态通过 Python 脚本在两个模型之间传输,从而减少了在多个模型或分析步骤之间传输元素信息的传统方法所带来的低效率和不可控误差。最后,从不同角度将机械响应和损伤状态的数值结果与实验结果进行了比较,并深入研究了 Z 销的桥接机制。结果表明,该模型在低速冲击时主要关键参数的最大误差为 10.41%,在冲击后拉伸时极限载荷的最大误差为 10.30%。模型的分层破坏状态和最终拉伸破坏模式与实验结果非常吻合。此外,对 FE 模型的综合分析表明,Z 形销的拔出力与其植入位置或拔出率无关,只有在 CFRP T 形接头达到一定的初始损坏程度后,Z 形销的加固作用才会显著显现。Rapid and scalable synthesis of novel carboxylated aramid nanofibers for simultaneously improving the strength and toughness of carbon fiber/epoxy laminatesYu Boshi, Wang Weitao, Zhou Guodong, Song Yihu, Peng Maodoi:10.1016/j.compscitech.2023.110320 快速、可扩展地合成新型羧基芳纶纳米纤维,以同时提高碳纤维/环氧层压板的强度和韧性Carbon fiber reinforced composites (CFRCs) are widely used in the aviation, aerospace and automotive industries. The modification of CFRCs with nanomaterials has attracted extensive research interests in recent years. Herein, we report the preparation of novel carboxylated aramid nanofibers (cANFs) by polymerization induced self-assembly, i.e. polycondensation of para-phenylenediamine with terephthaloyl chloride in the presence of a polyamide acid as both a dispersant and surface modifier, for the modification of epoxy resin and CFRCs. cANFs effectively improve the mechanical properties of epoxy resin, and after being sprayed onto CF fabrics, greatly improve the mechanical properties of CFRCs. With the addition of only 0.42 mg/cm2 of cANFs on each CF sheets, storage modulus, flexural strength, flexural modulus and total energy dissipation are enhanced by 27 %, 51 %, 29 % and 67 %, respectively; interlaminar shear strength (ILSS) and Mode II interlayer fracture toughness (G_IIC) are improved by 24 % and 74 %, respectively. cANFs can be comparable or even superior to most previously reported carbon nanomaterials in improving flexural strength and ILSS; and exceed most previously reported electrospun nanofibrous mats in increasing G_IIC. This study provides a new method for the rapid synthesis of functionalized ANFs to simultaneously increase the flexural properties and interlayer properties of CFRCs.碳纤维增强复合材料(CFRC)广泛应用于航空、航天和汽车行业。近年来,纳米材料对碳纤维增强复合材料的改性引起了广泛的研究兴趣。在此,我们报告了通过聚合诱导自组装(即对苯二胺与对苯二甲酰氯在聚酰胺酸作为分散剂和表面改性剂存在的情况下缩聚)制备新型羧基芳纶纳米纤维(cANFs),用于环氧树脂和 CFRC 的改性。cANFs 可有效改善环氧树脂的机械性能,喷涂到 CF 织物上后可大大改善 CFRC 的机械性能。在每块 CF 片材上仅添加 0.42 mg/cm2 的 cANFs,就能使储能模量、抗弯强度、抗弯模量和总能量耗散分别提高 27%、51%、29% 和 67%;层间剪切强度(ILSS)和模式 II 层间断裂韧性(G_IIC)分别提高 24% 和 74%。cANFs 在提高抗弯强度和 ILSS 方面可与之前报道的大多数碳纳米材料相媲美,甚至更胜一筹;在提高 G_IIC 方面超过了之前报道的大多数电纺纳米纤维毡。这项研究为快速合成功能化 ANFs 提供了一种新方法,可同时提高 CFRC 的抗弯性能和层间性能。来源:复合材料力学仿真Composites FEM

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