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
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。
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。
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。
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。