首页/文章/ 详情

【新文速递】2023年12月24日固体力学SCI期刊最新文章

24天前浏览380

今日更新:Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 4 篇

Mechanics of Materials

Topological boundary states in micropolar gyroelastic continua

Mohamed Shaat, Xin-Lin Gao

doi:10.1016/j.mechmat.2023.104902

微波陀螺弹性连续体中的拓扑边界态

The study of topology in elastic media has been primarily focused on achieving non-trivial topological states in discrete elastic lattices through active or chiral microscopic interactions. Realization of such topological states in continuous elastic media remains largely unexplored. In this study, a new continuum theory of micropolar gyroelasticity is developed and applied to attain non-trivial topological boundary states in elastic continua. According to the new theory, an elastic continuum is composed of elastically interacting micro-volume elements that can translate and rotate and are connected at their mass centers to gyroscopes, which contribute to the linear and orbital angular momenta but not to the spin angular momentum of the continuum. By applying this micropolar gyroelasticity theory to elastic media with both periodic and finite domains, the emergence of topological boundary states in 2D micropolar gyroelastic continua is demonstrated. Through using the Floquet–Bloch method for periodic domains, the bulk-boundary correspondence is analytically established, and the emergence of non-trivial topological bulk states characterized by Mexican-hat band structures is observed. In addition, by employing an asymptotic analytical model based on the extended Bloch theorem and performing numerical analyses of micropolar gyroelastic continua with finite domains of different geometries, it is shown that the non-trivial Mexican-hat band structure is associated with and provides protection for topological boundary states confined at the boundaries. Finally, the application of the newly developed micropolar gyroelasticity theory to Zinc-blende structured materials (including ZnTe, GaP, InP and ZnS) reveals that the emergence of the topological boundary states in an elastic continuum is not triggered solely by the gyroscopic effect but also depends on the material properties of the micropolar continuum. This study provides new insights into extending notions and methods of topology to analyze elastic continua, paving the way for the practical implementation of topological mechanical systems in various engineering applications.

弹性介质拓扑学的研究主要集中在通过主动或手性微观相互作用在离散弹性晶格中实现非三维拓扑状态。在连续弹性介质中实现这种拓扑状态在很大程度上仍未得到探索。在本研究中,我们提出了一种新的微极性陀螺弹性连续理论,并将其应用于在弹性连续体中实现非三维拓扑边界态。根据新理论,弹性连续体由弹性相互作用的微体积元素组成,这些元素可以平移和旋转,并在其质心处与陀螺仪相连,陀螺仪对连续体的线性角动量和轨道角动量有贡献,但对自旋角动量没有贡献。通过将这种微陀螺弹性理论应用于具有周期性和有限域的弹性介质,证明了二维微陀螺弹性连续体中拓扑边界态的出现。通过对周期性域使用 Floquet-Bloch 方法,分析建立了体-界对应关系,并观察到以墨西哥帽带结构为特征的非三维拓扑体态的出现。此外,通过采用基于扩展布洛赫定理的渐近分析模型,并对具有不同几何形状的有限畴的微极陀螺弹性连续体进行数值分析,证明了非微观墨西哥帽带结构与限制在边界的拓扑边界态相关,并为其提供保护。最后,将新开发的微波陀螺弹性理论应用于锌蓝晶结构材料(包括 ZnTe、GaP、InP 和 ZnS),发现在弹性连续体中拓扑边界态的出现并非仅由陀螺效应引发,还取决于微波连续体的材料特性。这项研究为扩展拓扑学的概念和方法以分析弹性连续体提供了新的见解,为拓扑机械系统在各种工程应用中的实际实现铺平了道路。


International Journal of Plasticity

A dislocation-density-based crystal plasticity model for FCC nanocrystalline metals incorporating thermally-activated depinning from grain boundaries

Jonathan Cappola, Jian Wang, Lin Li

doi:10.1016/j.ijplas.2023.103863

基于位错密度的面心立方纳米晶金属晶体塑性模型,其中包含晶界热激活去氧化作用

A novel dislocation-density-based crystal plasticity model for nanocrystalline face-centered cubic metals is developed based on the thermally-activated mechanism of dislocations depinning from grain boundaries. Dislocations nucleated from grain boundary dislocation sources are assumed to be the primary carriers of plasticity in the nanocrystals. The evolution of the dislocation density thereby involves a competition between the nucleation of dislocations from grain boundary defect structures, such as ledges, and the absorption of dislocations into the grain boundary via diffusion processes. This model facilitates the simulation of plastic deformation in nanocrystalline metals, with consideration of the initial microstructure resulting from a particular processing method, to be computed as a direct result of dislocation-mediated plasticity only. The exclusion of grain boundary-mediated plasticity mechanisms in the formulation of the crystal plasticity model allows for the exploration of the fundamental role dislocations play in nanocrystalline plasticity. The combined effect of average grain size, grain size distribution shape, and initial dislocation density on the mechanical performance and strain-rate sensitivity are explored with the model. Further, the influence of the grain boundary diffusivity on post-yielding strain-hardening behavior is investigated to discern the impact that the choice of processing route has on the resulting deformation response of the material.

基于晶界位错降解的热激活机制,为纳米晶面心立方金属建立了一种基于位错密度的新型晶体塑性模型。假定从晶界位错源成核的位错是纳米晶体塑性的主要载体。因此,位错密度的演化涉及晶界缺陷结构(如台阶)中的位错成核与通过扩散过程吸收到晶界中的位错之间的竞争。该模型有助于模拟纳米晶金属的塑性变形,考虑到特定加工方法产生的初始微观结构,只计算位错介导塑性的直接结果。在制定晶体塑性模型时排除晶界介导的塑性机制,可以探索位错在纳米晶塑性中的基本作用。该模型探讨了平均晶粒尺寸、晶粒尺寸分布形状和初始位错密度对机械性能和应变速率敏感性的综合影响。此外,还研究了晶界扩散性对屈服后应变硬化行为的影响,以了解加工路线的选择对材料变形响应的影响。


Thin-Walled Structures

Nonlinear Forced Vibrations of Functionally Graded Three-phase Composite Cylindrical Shell Subjected to Aerodynamic Forces, External Excitations and Hygrothermal Environment

T. Liu, H.Y. Zheng, W. Zhang, Y. Zheng, Y.J. Qian

doi:10.1016/j.tws.2023.111511

受空气动力、外部激励和湿热环境影响的功能分级三相复合圆柱壳体的非线性受迫振动

In this paper, the new functionally graded three-phase composite cylindrical shell is assumed as a common structure in the carrier rocket in the future, and we creatively study the nonlinear forced vibration of this cylindrical shell considering the interaction of different factors in the complex operating environment, including the aerodynamic forces, external excitations, and hygrothermal environment. Based on the first-order shear deformation theory, Von-Karman geometric nonlinear theory, and Hamilton's principle, we derive the nonlinear partial differential equations of motion of the functionally graded three-phase composite cylindrical shell. Considering the axisymmetry of the perfect circular shell, there is a 1:1 internal resonance between the conjugate modes of this cylindrical shell. On this basis, the nonlinear forced vibration of the cylindrical shell is investigated by a combination of Galerkin's method and the pseudo-arc length continuation method. Matcont toolbox can directly solve the ordinary differential equations to obtain the nonlinear frequency response curves. The method can effectively obtain both stable and unstable solutions, avoiding the mathematical difficulties encountered in the formulation process, and facilitating the study of the effects of parametric variables on the resonance response in complex environments. The results show that the variation of material parameters and the complex environment have important effects on the nonlinear resonance response of functionally graded three-phase composite cylindrical shell.

本文将新型功能分级三相复合材料圆柱壳体假定为未来运载火箭的常用结构,考虑到复杂工作环境中不同因素的相互作用,包括空气动力、外部激励和湿热环境,创造性地研究了该圆柱壳体的非线性受迫振动。基于一阶剪切变形理论、冯-卡曼几何非线性理论和汉密尔顿原理,我们推导出了功能分级三相复合圆柱壳的非线性偏微分运动方程。考虑到完美圆壳的轴对称性,该圆柱壳的共轭模之间存在 1:1 的内部共振。在此基础上,结合 Galerkin 方法和伪弧长延续方法研究了圆柱壳的非线性受迫振动。Matcont 工具箱可以直接求解常微分方程,从而得到非线性频率响应曲线。该方法能有效地得到稳定解和不稳定解,避免了公式化过程中遇到的数学困难,便于研究参数变量对复杂环境下共振响应的影响。结果表明,材料参数的变化和复杂环境对功能分级三相复合材料圆柱壳的非线性共振响应有重要影响。


The added mass of a biaxial tensioned membrane in still air

Shaochen Yang, Bing Zhao, Wujun Chen

doi:10.1016/j.tws.2023.111531

静止空气中双轴拉伸薄膜的附加质量

It is well known that added mass significantly impacts the vibration of membrane structures in still air. Numerous theoretical, numerical, and experimental studies have been conducted on the added mass of axial tensioned membranes. However, the added mass of biaxial tensioned membranes subjected to different tensile forces in two directions in still air remains unclear. Therefore, this study focuses on investigating the added mass of biaxial tensioned membranes in still air. Firstly, this paper proposes a simplified theoretical model for the added mass of biaxial tensioned membranes in still air based on the energy conservation law. To validate the accuracy of the proposed model, a modal testing system for a rectangular membrane is designed to identify the frequencies of biaxial tensioned membranes in still air. In the experimental system, the utilization of a laser displacement sensor array is to obtain the time-displacement information of observation points. Then, a combination of Fast Fourier Transform (FFT) and Stochastic Subspace Identification (SSI) methods is employed for modal identification. Comparative analysis between the experimental and theoretical model results demonstrates an excellent agreement in frequencies. Additionally, the proposed added mass model is closer to the experimental added mass than other models, with a maximum deviation of only 4.77%. This research provides a reference for the study of the impact of air on the ground vibration of membranes.

众所周知,附加质量对静止空气中膜结构的振动有很大影响。关于轴向拉伸膜的附加质量,已经进行了大量的理论、数值和实验研究。然而,在静止空气中受到两个方向不同拉伸力的双轴拉伸膜的附加质量仍不清楚。因此,本研究将重点放在研究静止空气中双轴拉伸膜的附加质量上。首先,本文基于能量守恒定律,提出了静止空气中双轴拉伸膜附加质量的简化理论模型。为了验证所提模型的准确性,本文设计了一个矩形膜的模态测试系统,以确定静止空气中双轴张拉膜的频率。在实验系统中,利用激光位移传感器阵列获取观测点的时间位移信息。然后,结合快速傅立叶变换(FFT)和随机子空间识别(SSI)方法进行模态识别。实验结果与理论模型结果的对比分析表明,两者在频率上非常一致。此外,与其他模型相比,所提出的附加质量模型更接近于实验附加质量,最大偏差仅为 4.77%。这项研究为研究空气对膜材地面振动的影响提供了参考。


A simple SIF determination method for cracked orthotropic cylindrical shell by means of stress ratio

Rong Li, Shuai Bai, Meng Yang, Bin Liang, Ke-jun Hu

doi:10.1016/j.tws.2023.111532

利用应力比确定开裂正交圆柱壳 SIF 的简单方法

A convenient and universal calculation method for stress intensity factor (SIF) in cracked orthotropic cylindrical shell under diverse loadings is described. The present expressions are derived from traditional classical numerical method and simplified by extracting and eliminating the complex but regular parameters. A simple relation between SIF and crack tip stress from finite element method (FEM) is constructed by means of reference problem and unknown problem, then a simple SIF formulation can be realized and the impact of material orthotropy is considered. The feasibility and advantages of present study are proved to be analyzed by comparing against published results.

本文介绍了在不同载荷作用下,开裂的正交圆柱壳体应力强度因子(SIF)的一种方便通用的计算方法。本表达式源自传统的经典数值方法,并通过提取和消除复杂但规则的参数进行了简化。通过参考问题和未知问题,构建了有限元法(FEM)中 SIF 与裂纹尖端应力之间的简单关系,从而实现了简单的 SIF 公式,并考虑了材料正交性的影响。通过与已发表的结果进行对比分析,证明了本研究的可行性和优势。


Study on stability of H-type section aluminum alloy perforated members under axial compression and eccentric compression around weak axis

Wenyuan Kong, Hang Yang, Liang Zhou, Zhiquan Xing, Yu Chen, Wei Chen, En Lin

doi:10.1016/j.tws.2023.111533

H 型截面铝合金穿孔构件在轴向压缩和围绕弱轴的偏心压缩条件下的稳定性研究

Aluminum alloy components have the advantages of light weight, high strength, favorable machinability, and good acid corrosion resistance, which can greatly reduce maintenance costs and easy to make the structures with beautiful appearance. Based on the shortcomings of existing research fields, the stability of H-type section 6082-T6 aluminum alloy perforated members under axial compression and eccentric compression around weak axis is studied by combining experimental and numerical simulation methods in this paper. The test results of aluminum alloy members under axial compression and aluminum alloy members under eccentric compression around weak axis with different web opening numbers, opening diameters, slenderness ratios and eccentric distances are analyzed. The verified finite element model is used to carry out the extensive parameter analysis focusing on the key variables. Based on the test and numerical simulation results of the stability bearing capacity of 134 members, the design methods for H-type section aluminum alloy perforated members under axial compression and eccentric compression are proposed and evaluated by reference to the existing specification.

铝合金构件具有重量轻、强度高、可加工性好、耐酸腐蚀性好等优点,可大大降低维护成本,且易于制作成外形美观的结构。基于现有研究领域的不足,本文采用实验和数值模拟相结合的方法,研究了 H 型截面 6082-T6 铝合金穿孔构件在轴向压缩和绕弱轴偏心压缩下的稳定性。分析了不同腹板开孔数、开孔直径、细长比和偏心距的铝合金构件在轴向压缩和绕弱轴偏心压缩下的试验结果。利用经过验证的有限元模型对关键变量进行了广泛的参数分析。根据 134 个构件的稳定承载力试验和数值模拟结果,提出了轴向压缩和偏心压缩条件下 H 型截面铝合金穿孔构件的设计方法,并参照现有规范进行了评估。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform振动复合材料非线性通用UG裂纹理论材料CAPP试验
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-05
最近编辑:24天前
Tansu
签名征集中
获赞 6粉丝 0文章 776课程 0
点赞
收藏
作者推荐

【新文速递】2023年12月15日复合材料SCI期刊最新文章

今日更新:Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 4 篇,Composites Science and Technology 3 篇Composites Part A: Applied Science and ManufacturingElectrostatically self-assembled Fe3O4@SiO2/MXene 3D interlayered structure improves Ku-band microwave absorption efficiency of epoxy-based nanocompositesBin Du, Guodong Zhang, Xianhua Huan, Nanqing Chen, Yushun Zhao, Bin Gao, Liqing Liudoi:10.1016/j.compositesa.2023.107956静电自组装Fe3O4@SiO2/MXene三维层间结构提高了环氧基纳米复合材料的ku波段微波吸收效率It is challenging to develop lightweight and efficient frequency-selective microwave absorption materials due to the trade-off between impedance matching and microwave attenuation ability. This study proposes a multiple heterointerfaces engineering strategy via electrostatically assembling to construct Fe3O4@SiO2/MXene 3D interlayer structure, which fully exerted the synergistic effect of dielectric-magnetic components. The 3D interlayer heterostructure achieves good impedance matching due to electromagnetic coupling and extended microwave propagation path. Simultaneously, massive charge transfer and redistribution at multiple heterointerfaces embedded in this structure boost the polarization relaxation and dielectric loss ability. Consequently, the prepared nanocomposites exhibit remarkable Ku-band microwave absorption efficiency (-60.9 dB at a thickness of 1.0 mm), and have demonstrated valid practicality via Tesla wireless transmission shielding experiments. This study opens exciting possibilities for progress in the structural design, facile preparation and practical application of high-performance Ku-band microwave absorption materials.由于需要在阻抗匹配和微波衰减能力之间进行权衡,开发轻质、高效的频率选择性微波吸收材料是一项具有挑战性的工作。本研究提出了通过静电组装构建Fe3O4@SiO2/MXene三维层间结构的多异质界面工程策略,充分发挥了介电-磁元件的协同效应。三维层间异质结构由于电磁耦合和微波传播路径的延长,实现了良好的阻抗匹配。同时,该结构中嵌入的多个异质界面的大量电荷转移和再分配增强了极化弛豫和介电损耗能力。结果表明,制备的纳米复合材料具有显著的ku波段微波吸收效率(在厚度为1.0 mm时为-60.9 dB),并通过特斯拉无线传输屏蔽实验证明了其实用性。本研究为高性能ku波段微波吸收材料的结构设计、简易制备和实际应用开辟了令人兴奋的可能性。A novel interfacial modification strategy to improve the wear resistance of PPESK compositesQingguang Bao, Nan Li, Bing Wang, Zhenguo Song, Bin Luo, Shan Cheng, Jingyao Feng, Mengting Li, Wenzhi Li, Yousi Chen, Xigao Jiandoi:10.1016/j.compositesa.2023.107966 一种提高PPESK复合材料耐磨性的新型界面改性策略High-speed and heavy-duty equipment transmission or rotation systems have experienced a significant increase in demand for wear-resistant, self-lubricating resin matrix composites. However, the interfacial interaction between the fillers and the matrix is nonetheless weak due to the fact that the composites are multi-component systems. This weak interaction negatively impacts wear resistance in practical applications. In this paper, a one-step modification method of multiple fillers based on coupling agent compounding by RSM design is proposed. The resulting PPESK composites exhibit excellent thermal (T5wt% = 517.6°C), mechanical (Rockwell hardness = 118 HRR), and wear (ω = 0.72 × 10-15m3/Nm) properties. In addition, PPESK composite bearings were prepared, which showed lightweight advantages, exhibited outstanding tribology performance (μ = 0.079, ω = 0.52×10-15m3/Nm), and demonstrated excellent media resistance (Swelling degree (90 days, 25℃) = 0.45%) in Jet fuel No.3. Therefore, these bearings have great application prospects in the field of aero-engine bearings.高速和重型设备的传动或旋转系统对耐磨、自润滑树脂基复合材料的需求显著增加。然而,由于复合材料是多组分体系,填料与基体之间的界面相互作用仍然很弱。在实际应用中,这种弱相互作用会对耐磨性产生负面影响。本文提出了一种基于RSM设计的偶联剂复合的多填料一步改性方法。得到的PPESK复合材料具有优异的热性能(T5wt% = 517.6°C)、力学性能(洛氏硬度= 118 HRR)和耐磨性能(ω = 0.72 × 10-15m3/Nm)。此外,制备的PPESK复合轴承具有重量轻的优点,具有优异的摩擦学性能(μ = 0.079, ω = 0.52×10-15m3/Nm),并且在3号喷气燃料中具有优异的耐介质性(膨胀度(90天,25℃)= 0.45%)。因此,这些轴承在航空发动机轴承领域具有很大的应用前景。Composites Part B: EngineeringMechanical behaviour of C-S-H agglomerates at multiscaleZhe Zhang, Qiang Zhu, Guoqing Gengdoi:10.1016/j.compositesb.2023.111140多尺度C-S-H团聚体的力学行为Calcium-Silicate-Hydrate (C-S-H) is the primary binding phase in cement and plays a crucial role in lifecycle performance of concrete. Understanding its multiscale mechanical properties is essential for optimizing its performance. In this study, we employed atomic force microscopy (AFM), nanoindentation and oedometric test to characterize multi-scale mechanical behaviours of C-S-H with different chemical composition and microstructure. Moreover, a calculation framework is used to bridge inter-scale gaps. Our results reveal the complex hierarchical features of C-S-H and its impact on mechanical properties including elastic, plastic, and viscous responses. We also identify the critical role of chemical composition including calcium-to-silica ratio and water content on the observed mechanical behaviours. Additionally, our multiscale model provides a valuable tool for rational design of C-S-H-based materials with tailored mechanical properties at less material cost.水合硅酸钙(C-S-H)是水泥中的主要结合相,对混凝土的生命周期性能起着至关重要的作用。了解其多尺度力学特性对优化其性能至关重要。本研究采用原子力显微镜(AFM)、纳米压痕和尺度测试对不同化学成分和微观结构的C-S-H的多尺度力学行为进行了表征。此外,还采用了一种计算框架来弥补尺度间的差距。我们的研究结果揭示了C-S-H的复杂层次特征及其对力学性能的影响,包括弹性、塑性和粘性响应。我们还确定了化学成分(包括钙硅比和水含量)对观察到的力学行为的关键作用。此外,我们的多尺度模型为以更低的材料成本合理设计具有定制力学性能的c - s - h基材料提供了有价值的工具。Self-alignment of amino-functionalized Ti3C2Tx modified with cerium-doped ZIF-8 nanocontainer towards anti-corrosive/wear and self-healing applicationCan He, Meng Cai, Yu Huang, Xiaoqiang Fan, Minhao Zhudoi:10.1016/j.compositesb.2023.111144 掺杂铈的ZIF-8纳米容器修饰氨基功能化Ti3C2Tx的自对准及抗腐蚀磨损自修复应用Despite Ti3C2Tx MXene has certified tremendous promise for improving the anti-corrosion/wear of epoxy resin, it falls short of matching the protective standards under long-term extreme conditions. Herein, 2-methylimidazole zinc salt ZIF-8 was grown in-situ on amino-functionalized Ti3C2Tx nanosheets and doped with cerium cations (P+-Ti3C2Tx@ZCe). The Ti3C2Tx-based composite was then parallel arranged within epoxy coating utilizing electrophoretic deposition technique to prepare a novel self-healing intelligent coating (PMX@ZCe). The encapsulation structure of P+-Ti3C2Tx@ZCe was investigated by XRD, FTIR, XPS, FE-SEM, TEM, Zeta potential and TG techniques. Furthermore, the corrosion/wear resistance and self-healing performances of PMX@ZCe were discussed detailedly and the strengthening mechanism of P+-Ti3C2Tx@ZCe was revealed. Results indicate that PMX@ZCe maintains the highest |Z|0.01Hz value of 1.24 × 1010 Ω cm2 after 4 weeks of electrochemical test and exhibits excellent self-healing efficiency of 153 % under artificial scratch, which is ascribed to the release of Ce3+/Ce4+ that could form insoluble protective films at the coating/metal interface. The wear rate of PMX@ZCe is 2.29 × 10−5 mm3/N · m about 56 % lower than that of EP. PMX@ZCe possesses satisfactory corrosion/wear protection performance, thanks to the synergy of good interfacial interaction, parallel-aligned barrier effect and active-passive protection. This work provides a new design thinking for MXene-based intelligent protective coatings that can meet the demands of multi-service environments.尽管Ti3C2Tx MXene在提高环氧树脂的抗腐蚀/磨损性能方面有着巨大的潜力,但在长期极端条件下,它无法达到保护标准。本文将2-甲基咪唑锌盐ZIF-8原位生长在氨基功能化的Ti3C2Tx纳米片上,并掺杂铈阳离子(P+-Ti3C2Tx@ZCe)。然后利用电泳沉积技术将ti3c2tx基复合材料平行排列在环氧涂层中,制备了一种新型的自修复智能涂层(PMX@ZCe)。采用XRD、FTIR、XPS、FE-SEM、TEM、Zeta电位和TG等技术研究了P+-Ti3C2Tx@ZCe的包封结构。详细讨论了PMX@ZCe的耐蚀磨损性能和自愈性能,揭示了P+-Ti3C2Tx@ZCe的强化机理。结果表明:经过4周的电化学测试,PMX@ZCe保持了1.24 × 1010 Ω cm2的最高|Z|0.01Hz值,在人为划伤下表现出了153 %的优异自愈效率,这是由于Ce3+/Ce4+的释放可以在涂层/金属界面形成不溶性保护膜。PMX@ZCe的磨损率为2.29 × 10−5 mm3/N·m,比EP低56 %。PMX@ZCe由于良好的界面相互作用、平行排列的屏障效应和主动被动保护的协同作用,具有令人满意的腐蚀/磨损保护性能。该工作为基于mxeni的智能防护涂层提供了一种新的设计思路,可以满足多服务环境的需求。Synchronous manipulation of heterointerfaces and atomic hybrids in bimetallic MAX phase composites for advanced electromagnetic wave absorptionTongtong Xu, Jun Li, Dongpeng Zhao, Zhengyu Zhang, Xilong Li, Juan Cui, Xiping Chen, Guangai Sun, Zhongxiang Zhoudoi:10.1016/j.compositesb.2023.111148 用于先进电磁波吸收的双金属MAX相复合材料异质界面和原子杂化的同步操纵Rational constructing multi-phase interfaces and hetero-substituted sites structures holds extraordinary potential for harnessing tailorable electromagnetic (EM) responses and fascinating EM wave absorption. Herein, a series of new bimetallic MAX phase hybrid composites (Ti1-xVx)2AlCf with diverse dielectric behaviors integration are synthesized via a simple thermally driven gradient sintering strategy, using carbon fiber as the initial carbon source. Their chemical compositions, physical structures and EM properties are studied in detail, focusing on the resultant temperature and M-site vanadium atom substitutional engineering. Specifically, benefiting from the co-boosted interfacial/dipole polarization capabilities caused by the simultaneous manipulation of heterogeneous boundary states and intrinsic dipoles distribution at 1350 °C, the TiVAlCf composite exhibits an ultrahigh minimum reflection loss of −59.13 dB and an effective absorption bandwidth of 4.93 GHz, with a matching thickness of only 1.53 mm. Furthermore, multilayer gradient metamaterial model and a high-temperature tail nozzle model are constructed to further highlight the advanced EM functional application capacity of these MAX-based materials. This work is expected to provide an innovative platform for understanding cooperative multi-dielectric coupling mechanisms in the controllable design of high-efficient hybrid composite absorbers.合理构建多相界面和异取代位结构对于利用可定制的电磁响应和迷人的电磁波吸收具有非凡的潜力。本文以碳纤维为初始碳源,通过简单的热驱动梯度烧结策略,合成了一系列具有不同介电行为集成的新型双金属MAX相杂化复合材料(Ti1-xVx)2AlCf。详细研究了它们的化学组成、物理结构和电磁性能,重点研究了合成的温度和m位钒原子取代工程。具体来说,得益于在1350 °C时同时操纵非均质边界态和本征偶极子分布所引起的界面/偶极子极化能力的共同增强,TiVAlCf复合材料的最小反射损耗为- 59.13 dB,有效吸收带宽为4.93 GHz,匹配厚度仅为1.53 mm。构建了多层梯度超材料模型和高温尾喷嘴模型,进一步凸显了这些max基材料的先进EM功能应用能力。这项工作有望为理解高效混合复合材料吸波器可控设计中的协同多介电耦合机制提供一个创新平台。Dual-functional Polyindole/MXene composite for superior proton storage and corrosion protectionNianting Chen, Jing He, Hongye Xuan, Jing Jin, Ke Yu, Minjie Shi, Chao Yandoi:10.1016/j.compositesb.2023.111145 双功能聚吲哚/MXene复合材料具有优异的质子储存和防腐性能Although Polyindole (Pind) with a π-conjugated polymeric structure has been regarded as a promising organic material, the loosely packed and brittle backbones still hinder its long-term usage stability for various applications. Herein, a novel Pind/MXene composite with a 3D robust architecture has been developed by confining Pind nanoparticles in layered MXene through a simple and mild polymerization approach, which shows unique dual functionality for energy storage and corrosion protection for tcorrosion protection for the first time. On the one hand, the Pind/MXene composite as an electrode material exhibits a rapid, reversible, and stable energy storage behavior with a large proton-storage capacity of 118 mAh g−1 and excellent cycle stability (∼98.2 % after 2000 cycles) in aqueous electrolyte. On the other hand, the Pind/MXene composite as an anti-corrosion additive is introduced into the epoxy resin to achieve a coating, which shows a long-term anti-corrosion performance with a low corrosion rate of 9.17×10−6 mm a−1 and a high corrosion inhibition efficiency of 99.72 %. Furthermore, theoretical calculations prove the obvious electron transfer between Pind and MXene, endowing the Pind/MXene composite with enhanced redox capability, high electrochemical activity and robust structural stability, suggesting its great potential as the bi-functional material for high-performance energy storage and corrosion protection.具有π共轭聚合物结构的聚吲哚(Pind)被认为是一种很有前途的有机材料,但其骨架的松散和脆性仍然阻碍了其在各种应用中的长期使用稳定性。本文通过一种简单而温和的聚合方法,将Pind纳米颗粒限制在层状MXene中,开发出一种具有3D坚固结构的新型Pind/MXene复合材料,该复合材料首次显示出独特的储能和防腐蚀双重功能。一方面,Pind/MXene复合材料作为电极材料表现出快速、可逆和稳定的能量存储行为,具有118 mAh g - 1的大质子存储容量和优异的循环稳定性(循环2000次后为98.2% %)。另一方面,将Pind/MXene复合材料作为防腐添加剂引入到环氧树脂中,形成涂层,具有长期防腐性能,腐蚀速率低,为9.17×10−6 mm a−1,缓蚀效率高达99.72 %。此外,理论计算证明了Pind与MXene之间存在明显的电子转移,使得Pind/MXene复合材料具有较强的氧化还原能力、较高的电化学活性和较强的结构稳定性,表明其具有作为高性能储能和防腐双功能材料的巨大潜力。Composites Science and TechnologyAdditive manufacturing of hybrid piezoelectric/magnetic self-sensing actuator using pellet extrusion and immersion precipitation with statistical modelling optimizationJi Eun Lee, Yu-Chen Sun, Isobel Lees, Hani E. Naguibdoi:10.1016/j.compscitech.2023.110393 基于球团挤压和浸没沉淀的压电/磁混合自传感致动器增材制造及统计建模优化Additive manufacturing is a growing field of fast reliable processing as it can fabricate complex designs, both internally and externally. Multi-stimuli-responsive/-functional polymers can respond to numerous stimuli and execute multiple tasks. A thin flexible hybrid piezoelectric–magnetic self-sensing actuator (HPMSA) is printed utilizing pellet extrusion and immersion precipitation 3D printing (ip3DP) to enhance its performance as both a sensor and an actuator. Utilizing molecular interactions and pores created within the structure, ip3DP showcased a more stable and effective self-sensing actuator than pellet extruded samples. Additionally, HPMSA fabricated using either additive manufacturing methods had a higher overall crystal content of 62.1 % compared to the conventional process of compression molding and mechanical stretching, highlighting its scale-up fabrication whilst promoting piezoelectric crystals. For optimization, kernel ridge regression model was utilized to predict the optimal ip3DP condition, which was experimentally validated. As a vibration damper, the ip3DP HPMSA with an optimized geometry showcased an effective high voltage sensing output of 13 mV/g and maximum weighted damping of 1.8 m/s2, lowering passenger health risks to “caution zone” in high vibration environments. The thin and flexible HPMSA provides understanding into multi-stimuli/-functional materials, simultaneous alignment, and vibration control.增材制造是一个快速可靠的加工领域,因为它可以制造复杂的设计,无论是内部还是外部。多刺 激反应/功能聚合物可以对多种刺 激作出反应并执行多种任务。利用颗粒挤压和浸没沉淀3D打印技术(ip3DP)打印出一种薄型柔性混合压电-磁自传感执行器(HPMSA),以提高其传感器和执行器的性能。利用分子相互作用和结构内产生的孔隙,ip3DP展示了比颗粒挤出样品更稳定、更有效的自传感驱动器。此外,与传统的压缩成型和机械拉伸工艺相比,使用增材制造方法制造的HPMSA的总晶体含量更高,为62.1 %,突出了其规模化制造,同时促进了压电晶体的发展。为了优化,利用核脊回归模型预测ip3DP的最优条件,并进行了实验验证。作为减震器,经过优化的ip3DP HPMSA的有效高压感应输出为13 mV/g,最大加权阻尼为1.8 m/s2,将乘客的健康风险降低到高振动环境中的“警戒区”。薄而灵活的HPMSA提供了对多刺 激/功能材料,同步校准和振动控制的理解。Effect of fabrication process on the microstructure and mechanical performance of carbon fiber reinforced PEEK composites via selective laser sinteringShuxiang Zhang, Haibin Tang, Danna Tang, Tingting Liu, Wenhe Liaodoi:10.1016/j.compscitech.2023.110396 选择性激光烧结制备工艺对碳纤维增强PEEK复合材料微观结构和力学性能的影响Carbon fiber reinforced PEEK (CF/PEEK) composites via selective laser sintering (SLS) are highly promising technologies for the fabrication of polymer-based components with excellent mechanical behavior. In order to further enhance the performance of SLS-CF/PEEK composites, the mixed CF/PEEK powders are designed and CF/PEEK composites are fabricated via SLS under different fabrication process parameters. The effect of laser power, layer thickness, paving speed, fiber weight fraction, and fiber length on the microstructure and mechanical performance along the powder spreading direction is investigated for SLS-CF/PEEK. The results show that the failure strength of 117 MPa is achieved while the layer thickness of 0.08 mm is adopted. Moreover, the fiber weight fraction of 15% is proven to be suited during the fabrication of SLS-CF/PEEK. The maximum failure strength is better than the results of SLS-CF/PEEK with the fiber weight fraction of 10%, and the average elastic modulus reaches 8400 MPa, which is the best result among those published works. In addition, it is found that the correlation between the failure strength and paving speed is non-monotonic, and the higher strength is obtained when the longer carbon fiber is used. Different from the distinct trends in failure strength, the sensitivity of modulus is much less obvious for SLS-CF/PEEK. This work provides guidance for the printing of high-strength CF/PEEK composites.采用选择性激光烧结(SLS)技术制备碳纤维增强PEEK (CF/PEEK)复合材料是一种具有良好力学性能的聚合物基复合材料。为了进一步提高SLS-CF/PEEK复合材料的性能,设计了CF/PEEK混合粉末,并在不同的制备工艺参数下通过SLS制备了CF/PEEK复合材料。研究了激光功率、铺层厚度、铺层速度、纤维重量分数和纤维长度对SLS-CF/PEEK粉末铺层方向微观结构和力学性能的影响。结果表明:当层厚为0.08 mm时,破坏强度达到117 MPa;此外,在SLS-CF/PEEK的制备过程中,纤维重量分数为15%是合适的。最大破坏强度优于纤维质量分数为10%的SLS-CF/PEEK,平均弹性模量达到8400 MPa,是已发表的研究成果中效果最好的。此外,还发现其破坏强度与铺装速度呈非单调相关关系,且碳纤维使用时间越长强度越高。与破坏强度变化趋势明显不同,SLS-CF/PEEK的模量敏感性不明显。本工作为高强度CF/PEEK复合材料的打印提供了指导。Robot-assisted laser additive manufacturing for high-strength/low-porosity continuous fiber-reinforced thermoplastic compositesZhen Ouyang, Lei Yang, Zhanpeng Pi, Zhihao Wang, Chunze Yan, Yusheng Shidoi:10.1016/j.compscitech.2023.110397 高强度/低孔隙度连续纤维增强热塑性复合材料的机器人辅助激光增材制造Additive manufacturing (AM) of continuous fiber-reinforced thermoplastic composites (CFRTPCs) has become a hot area for both academia and industry. In this paper, a robot-assisted laser additive manufacturing (RLAM) technique is proposed, which involves utilizing a laser beam to heat the filament to a semi-molten state, followed by compacting it with a roller and bonding it layer by layer to create densely structured components. Firstly, an integrated framework of hardware, software, and control systems is presented. Then, the relationship between the processing parameters and the properties of the final specimens was examined. Finally, a process strategy was proposed to improve the forming accuracy. Due to the effective impregnation of continuous carbon fibers, the printed CFRTPCs using the LRAM process exhibit comparatively low porosity and superior mechanical performance. Specifically, the flexural strength, flexural modulus, and interlayer shear strength reached 584 MPa, 43.7 GPa, and 28.0 MPa, respectively. The prepared specimens boast a porosity of 0.19%, approaching levels achieved through autoclave processes. In addition, it was found that the dynamic offset of the yaw axis could be utilized to correct the deviation of the actual forming path due to the pultrusion force, thus making the position of the towpreg under the rollers controllable and improving the accuracy of the parts. This new method combines the advantages of industrial robotics and laser&roller-based continuous fiber additive manufacturing processes to enable high-performance additively manufactured large and complex CFRTPCs, which shows great potential for printing lightweight structures in the rail transit and aerospace industries.连续纤维增强热塑性复合材料(cfrtpc)的增材制造(AM)已成为学术界和工业界的热门领域。本文提出了一种机器人辅助激光增材制造(RLAM)技术,该技术包括利用激光束将灯丝加热到半熔融状态,然后用滚轮压实并逐层粘合以创建密集结构的部件。首先,给出了硬件、软件和控制系统的集成框架。然后,研究了工艺参数与最终试样性能的关系。最后,提出了提高成形精度的工艺策略。由于连续碳纤维的有效浸渍,采用LRAM工艺打印的cfrtpc具有相对较低的孔隙率和优越的力学性能。其中,抗弯强度、抗弯模量和层间抗剪强度分别达到584 MPa、43.7 GPa和28.0 MPa。制备的试样孔隙率为0.19%,接近通过高压灭菌工艺达到的水平。此外,还发现可以利用横摆轴的动态偏移量来修正由于拉挤力造成的实际成形路径偏差,从而使托辊下的托辊位置可控,提高了零件的精度。这种新方法结合了工业机器人技术和基于激光和滚轴的连续纤维增材制造工艺的优势,可以实现高性能增材制造大型复杂cfrtpc,这在轨道交通和航空航天工业的轻型结构打印中显示出巨大的潜力。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈