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【新文速递】2024年11月2日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 3 篇

International Journal of Solids and Structures

OXFORD-UMAT: An efficient and versatile crystal plasticity framework

Eralp Demir, Alvaro Martinez-Pechero, Chris Hardie, Edmund Tarleton

doi:10.1016/j.ijsolstr.2024.113110

牛津- umat:一种高效和通用的晶体塑性框架

The crystal plasticity-based finite element method is widely used, as it allows complex microstructures to be simulated and allows direct comparison with experiments. This paper presents the OXFORD-UMAT for Abaqus®, a novel crystal plasticity code that is publicly available online for researchers interested in using crystal plasticity. The model is able to simulate a wide range of materials and incorporates two different solvers based on the solution of slip increments and Cauchy stress with variants of state update procedures including explicit, semi-implicit, and fully-implicit for computational efficiency that can be set by the user based on the application. Constitutive laws are available for a range of materials with single or multiple phases for slip, creep, strain hardening, and back stress. The model includes geometrically necessary dislocations that can be computed using finite element interpolation functions by four alternative methods, including the total form with and without a correction for the dislocation flux, a widely used rate form, and a slip-gradient formulation. In addition, the initial strengthening and subsequent softening seen in irradiated materials can also be simulated with the model. The analysis is available in 2D (plane stress and plane strain) and 3D, including linear and quadratic elements. Here we include full derivations of the key equations used in the code and then demonstrate the capability of the code by modeling single-crystal and large-scale polycrystal cases. Comparison of OXFORD-UMAT with other available crystal plasticity codes for Abaqus® reveals the efficiency of the proposed approach, with the backup solver offering greater versatility for handling convergence issues commonly found in practical applications.

基于晶体塑性的有限元方法被广泛应用,因为它可以模拟复杂的微观结构,并可以与实验直接比较。本文介绍了Abaqus®的OXFORD-UMAT,这是一种新颖的晶体塑性代码,可供对晶体塑性感兴趣的研究人员在线公开获取。该模型能够模拟各种材料,并结合了两种不同的求解器,基于滑移增量和柯西应力的解,以及状态更新过程的变体,包括显式、半隐式和全隐式,可由用户根据应用设置计算效率。本构定律适用于滑移、蠕变、应变硬化和背应力的单相或多相材料。该模型包括几何上必要的位错,可以使用有限元插值函数通过四种替代方法计算,包括带和不带位错通量校正的总形式,广泛使用的速率形式和滑移梯度公式。此外,该模型还可以模拟辐照材料的初始强化和随后的软化过程。分析可在二维(平面应力和平面应变)和三维,包括线性和二次元。在这里,我们包括代码中使用的关键方程的完整推导,然后通过模拟单晶和大规模多晶情况来演示代码的能力。OXFORD-UMAT与Abaqus®的其他可用晶体塑性代码的比较揭示了所提出方法的效率,备用求解器为处理实际应用中常见的收敛问题提供了更大的通用性。


Journal of the Mechanics and Physics of Solids

Cyclic and helical symmetry-informed machine learned force fields: Application to lattice vibrations in carbon nanotubes

Abhiraj Sharma, Shashikant Kumar, Phanish Suryanarayana

doi:10.1016/j.jmps.2024.105927

循环和螺旋对称的机器学习力场:在碳纳米管晶格振动中的应用

We present a formalism for developing cyclic and helical symmetry-informed machine learned force fields (MLFFs). In particular, employing the smooth overlap of atomic positions descriptors with the polynomial kernel method, we derive cyclic and helical symmetry-adapted expressions for the energy, atomic forces, and phonons, i.e., lattice vibration frequencies and modes. We use this formulation to construct a symmetry-informed MLFF for carbon nanotubes (CNTs), where the model is trained through Bayesian linear regression, with the data generated from ab initio density functional theory (DFT) calculations performed during on-the-fly symmetry-informed MLFF molecular dynamics simulations of representative CNTs. We demonstrate the accuracy of the MLFF model by comparisons with DFT calculations for the energies and forces, and density functional perturbation theory calculations for the phonons, while considering CNTs not used in the training. In particular, we obtain a root mean square error of 1.4×10^-4 Ha/atom, 4.7×10^-4 Ha/Bohr, and 4.8 cm−1 in the energy, forces, and phonon frequencies, respectively, which are well within the accuracy targeted in ab initio calculations. We apply this framework to study phonons in CNTs of various diameters and chiralities, where we identify the torsional rigid body mode that is unique to cylindrical structures and establish laws for variation of the phonon frequencies associated with the ring modes and radial breathing modes. Overall, the proposed formalism provides an avenue for studying nanostructures with cyclic and helical symmetry at ab initio accuracy, while providing orders-of-magnitude speedup relative to such methods.

我们提出了一种开发具有循环和螺旋对称的机器学习力场(MLFF)的正式化方法。具体来说,我们采用原子位置描述符的平滑重叠与多项式核方法,导出了适用于循环和螺旋对称的能量、原子力和声子(即晶格振动频率和模式)的表达式。我们使用该形式化方法构建了一个适用于碳纳米管(CNTs)的对称信息机器学习力场(MLFF),其中模型通过贝叶斯线性回归进行训练,数据来自在飞行的对称信息MLFF分子动力学模拟期间通过密度泛函理论(DFT)计算生成的代表性CNTs。通过与DFT计算的能量和力的比较以及与密度泛函扰动理论计算的声子的比较,我们展示了MLFF模型的准确性,同时考虑了未用于训练的CNTs。特别是,我们获得了1.4×10^-4 Ha/atom、4.7×10^-4 Ha/Bohr和4.8 cm^-1的均方根误差,分别用于能量、力和声子频率,这些误差均在从头算计算的精度范围内。我们将这一框架应用于研究不同直径和手性的CNTs中的声子,其中我们识别出仅存在于圆柱形结构中的扭转刚体模式,并确定了与环模和径向呼吸模相关的声子频率的变化规律。总的来说,所提出的方法为在基本精度下研究具有周期性和螺旋对称性的纳米结构提供了途径,同时相对于此类方法实现了数个数量级的加速。


Mechanics of Materials

Electro-mechanical-carrier coupling model of single piezoelectric semiconductor fiber pull-out

Cai Ren, Chao Liu, Kaifa Wang, Baolin Wang

doi:10.1016/j.mechmat.2024.105188

单压电半导体光纤拉拔的机电载流子耦合模型

Recently, piezoelectric semiconductor (PS) fiber composite materials are widely used in flexible and wearable optoelectronics owing to their unique properties of possessing piezoelectricity and semiconduction simultaneously. It is of great importance to investigate the interfacial characteristics of PS fiber composites in case of interfacial damages between PS fiber and elastic matrix. In this paper, a theoretical model of single piezoelectric semiconductor fiber pull-out is established to study the electro-mechanical-carrier coupling characteristics and interfacial behaviors of fiber/matrix system. Based on the shear-lag theory, the stress transfer relationship between PS fiber and elastic matrix is investigated. Closed form solutions of distributions of relevant electromechanical fields and carrier perturbation are obtained as well. The results show that the change of material parameters and structure parameters can effectively tune the mechanical, electrical and interfacial properties of composite system. In addition, the value of initial carrier concentration which reveals the semiconducting property of PS fiber has a significant influence on the distributions of electromechanical fields. The findings are valuable for adjusting the electromechanical coupling behaviors of PS fiber via specific structure design and material combination in practical applications of piezotronics.

近年来,压电半导体(PS)纤维复合材料以其同时具有压电性和半导体性的独特性能,在柔性和可穿戴光电子领域得到了广泛的应用。研究聚苯乙烯纤维与弹性基体之间的界面损伤对研究聚苯乙烯纤维复合材料的界面特性具有重要意义。本文建立了单压电半导体光纤拉拔的理论模型,研究了光纤/基体体系的机电-载流子耦合特性和界面行为。基于剪切滞后理论,研究了PS纤维与弹性基体之间的应力传递关系。得到了相关机电场分布和载流子扰动的闭形式解。结果表明,材料参数和结构参数的改变可以有效地调整复合材料体系的力学、电学和界面性能。此外,反映PS光纤半导体特性的初始载流子浓度对其机电场分布有显著影响。研究结果对于在压电实际应用中通过特殊的结构设计和材料组合来调整PS光纤的机电耦合性能具有一定的参考价值。


Thin-Walled Structures

Research on Damage Repair and High-Velocity Impact Characteristics of Thermoplastic Composites

Feng JIN, Lulu LIU, Xinying ZHU, Zhihao XIE, Wei CHEN

doi:10.1016/j.tws.2024.112663

热塑性复合材料损伤修复及高速冲击特性研究

Low-velocity impact (LVI) can result in imperceptible damage to carbon fiber reinforced thermoplastic composites (CFRTP) laminates during service, leading to a reduction in structural strength. The thermal repair of damaged CFRTP laminates is conducted using the repairability of thermoplastic resin at high temperatures. However, the high-velocity impact characteristics of CFRTP laminates following thermal repair remain uncertain. This study examines CFRTP laminates made of two different materials (CF/PEEK and CF/PPS) with varying levels of low-velocity impact damage, and investigates the thermal repair process. A comparative experimental analysis examined the high-speed impact characteristics of CFRTP laminates under varying conditions. The results indicate that CF/PEEK laminates consistently exhibit superior compressive properties and impact resistance compared to CF/PPS laminates under similar conditions. Following damage from low-velocity impact, the compressive properties and high-velocity impact resistance of CFRTP laminates decrease, with CF/PPS laminates typically showing a lower performance retention rate. However, the thermal repair process proposed in this study significantly enhances the performance of CF/PPS laminates. Moreover, the degree of performance healing in CF/PPS laminates is consistently higher than that in CF/PEEK laminates, which is closely related to the semi-crystalline nature of PEEK resin.

低速冲击(LVI)会对碳纤维增强热塑性复合材料(CFRTP)层压板造成难以察觉的损伤,导致结构强度降低。利用热塑性树脂在高温下的可修复性,对受损CFRTP层叠板进行热修复。然而,热修复后CFRTP层压板的高速冲击特性仍然不确定。本研究考察了由两种不同材料(CF/PEEK和CF/PPS)制成的CFRTP层压板,它们具有不同程度的低速冲击损伤,并研究了热修复过程。对比实验分析了CFRTP复合材料在不同条件下的高速冲击特性。结果表明,在相同的条件下,CF/PEEK层压板始终表现出优于CF/PPS层压板的抗压性能和抗冲击性。低速冲击损伤后,CFRTP层压板的压缩性能和高速抗冲击性能下降,而CF/PPS层压板的性能保持率较低。然而,本研究提出的热修复工艺显著提高了CF/PPS层压板的性能。此外,CF/PPS复合材料的性能愈合程度始终高于CF/PEEK复合材料,这与PEEK树脂的半结晶性质密切相关。


Shear elastic buckling of corrugated steel plate shear walls with stiffeners considering torsional rigidity

Ruo-Min Wu, Chao-Qun Yu, Ling-Qi Wang, Jing-Zhong Tong

doi:10.1016/j.tws.2024.112646

考虑扭转刚度加筋波纹钢板剪力墙的剪切弹性屈曲

This paper conducted theoretical and numerical investigations on shear elastic buckling formulas of stiffened corrugated steel plate shear walls (SCSPSWs) considering torsional rigidities of stiffeners. Firstly, based on the orthotropic plate theory and the energy method, a theoretical model for the derivation of elastic buckling coefficients was established, introducing the torsional strain energy term of the stiffeners. On this basis, the variation law of the elastic buckling coefficient of the walls concerning the stiffener positions was studied, determining the optimal layout of the stiffeners. The formula for calculating the elastic buckling coefficient at any stiffener layout was provided. Furthermore, based on the stiffeners arranged in the optimal layout, the transition torsional rigidity of the stiffeners was determined, and the formulas for the elastic buckling coefficient of the SCSPSW with stiffeners considering torsional rigidity were proposed, in which the enhancement of torsional constraints provided by the stiffeners was measured by an enhancement factor. Finally, eigenvalue buckling analyses were performed based on finite element models to validate the theoretical analysis results on the optimal stiffener layout and elastic buckling coefficient.

本文对考虑加筋扭转刚度的加筋波纹钢板剪力墙剪切弹性屈曲公式进行了理论和数值研究。首先,基于正交各向异性板理论和能量法,建立了弹性屈曲系数推导的理论模型,引入了加劲筋扭转应变能项;在此基础上,研究了墙体弹性屈曲系数随加劲肋位置的变化规律,确定了加劲肋的最佳布置方式。给出了任意加劲肋布置时弹性屈曲系数的计算公式。在优化布置加劲肋的基础上,确定了加劲肋的过渡扭转刚度,提出了考虑扭转刚度的加劲肋SCSPSW弹性屈曲系数计算公式,并用增强系数来衡量加劲肋对扭转约束的增强作用。最后,基于有限元模型进行了特征值屈曲分析,验证了加强筋优化布局和弹性屈曲系数的理论分析结果。


Bending behaviors of 3D printed sandwich structures with functionally graded porous lattice cores

Meiling Fan, Tao Zeng, Rina Wu, Yuhua Cui, Guodong Xu, Xiaohong Wang, Su Cheng, Jue Zhao

doi:10.1016/j.tws.2024.112655

具有功能梯度多孔晶格芯的3D打印夹层结构的弯曲行为

A novel graded porous lattice core sandwich structure is presented to achieve a balance between lightweight and high mechanical performance for materials. An analytical model is proposed to investigate the bending responses of graded porous lattice core sandwich structures by utilizing the homogenization and dehomogenization method. A comprehensive parametric investigation on the mechanical behaviors of the graded lattice sandwich structures is conducted in order to design and optimize these materials. The precise control of porosity is implemented utilizing 3D printing techniques in this study. The theoretical results are validated by the experiments using 3D printed samples. It is found that mechanical properties can be improved through optimization of pore gradient distribution in the lattice core while maintaining a light weight of the sandwich structures. These findings offer valuable insights for designing tailored sandwich structures that are suitable for a diverse range of engineering applications.

提出了一种新型的梯度多孔晶格芯夹层结构,以实现材料轻量化和高机械性能之间的平衡。采用均匀化和去均匀化方法,建立了梯度多孔晶格芯夹层结构的弯曲响应分析模型。对梯度点阵夹层结构的力学行为进行了全面的参数化研究,从而对这些材料进行了设计和优化。在本研究中,利用3D打印技术实现了孔隙度的精确控制。通过3D打印样品的实验验证了理论结果。研究发现,在保持夹层结构轻量化的同时,通过优化晶格核孔隙梯度分布可以提高夹层结构的力学性能。这些发现为设计适合各种工程应用的定制夹层结构提供了有价值的见解。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemFluxAbaqus振动复合材料半导体通用电子电场理论材料分子动力学控制
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【新文速递】2024年10月31日复合材料SCI期刊最新文章

今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 7 篇,Composites Science and Technology 2 篇Composite StructuresThermoelastic contact of layer-substrate system: Effects of force-like interface and Kapitza thermal resistance modelsYibin Jiang, Pengyang Zhao, Wenwang Wudoi:10.1016/j.compstruct.2024.118675层-衬底系统的热弹性接触:类力界面和Kapitza热阻模型的影响Heterogenous materials composed of multiple layers with different material properties are commonly used for multi-functional engineering applications. Due to the existences of inevitable interfacial defects, discontinuities in displacement, stress, or thermal transmission often occur across the interfaces. This paper focus on the problem of layer-substrate system under three-dimensional sliding thermoelastic contact, and force-like imperfect interface and Kapitza thermal resistance interface defects are specially treated. By employing Fourier transforms, closed-form analytical expressions for the three-dimensional thermoelastic field of layer-substrate system with imperfect interface within Fourier spectral space are derived. The temperature and stress fields are computed using discrete convolution fast Fourier transform (DC-FFT) and the conjugate gradient method (CGM). Based on this model, the impact of defects on in-plane and out-of-plane stresses, von Mises stress, and the temperature field is investigated, and it is found that the force-like and Kapitza thermal resistance defects will result in discontinuities in stress and temperature field across the interface plane, and parametric analysis is performed for understanding the physical laws and key factors influencing the interface elastic fields discontinuities.多相材料是由具有不同材料性能的多层材料组成的,通常用于多功能工程应用。由于不可避免的界面缺陷的存在,在界面上经常出现位移、应力或热传递的不连续。本文重点研究了三维滑动热弹性接触下的层-基体系问题,重点研究了类力缺陷界面和Kapitza热阻界面缺陷。利用傅里叶变换,导出了具有不完全界面的层-衬底体系三维热弹性场的傅里叶谱空间封闭解析表达式。采用离散卷积快速傅里叶变换(DC-FFT)和共轭梯度法(CGM)计算了温度场和应力场。基于该模型,研究了缺陷对面内、面外应力、von Mises应力和温度场的影响,发现类力缺陷和Kapitza热阻缺陷会导致界面平面上的应力场和温度场不连续,并进行了参数化分析,以了解影响界面弹性场不连续的物理规律和关键因素。Composites Part A: Applied Science and ManufacturingPreparation of biconnected carbon fiber/Cu composites with excellent thermal and mechanical propertiesHongda Guan, Xinbo He, Pengfei Zhu, Zijian Zhang, Junchen Huang, Xuanhui Qudoi:10.1016/j.compositesa.2024.108564具有优异热力学性能的双连接碳纤维/Cu复合材料的制备A continuous three-dimensional CF network was constructed to fabricate biconnected CF/Cu composites. The effects of two-step electrodeposition and CF volume fraction on the thermal and mechanical properties of the composites were investigated. The results indicate that the two-step electrodeposition effectively fills the contact pores between CFs, reducing the porosity of the composites by 50 % compared to one-step electrodeposition. Moreover, the thermal conductivity of the composites prepared by two-step electrodeposition is enhanced by about 20 W m−1 K−1 relative to one-step electrodeposition, accompanied by a 25 % increase in bending strength. By controlling electrodeposition time, varying CF content on Cu foam can be obtained, enabling production of CF/Cu composites with different CF volume fractions. The 50 vol% CF/Cu composite exhibits excellent thermal conductivity, appropriate coefficient of thermal expansion, and outstanding bending strength.构建了连续三维CF网络,制备了双连接CF/Cu复合材料。研究了两步电沉积工艺和CF体积分数对复合材料热性能和力学性能的影响。结果表明,两步电沉积有效地填充了碳纤维之间的接触孔,与一步电沉积相比,复合材料的孔隙率降低了50% %。此外,与一步电沉积相比,两步电沉积制备的复合材料的导热系数提高了约20 W m−1 K−1,同时抗弯强度提高了25 %。通过控制电沉积时间,可以获得不同CF含量的Cu泡沫,从而制备出不同CF体积分数的CF/Cu复合材料。50 vol%的CF/Cu复合材料具有优良的导热性、适宜的热膨胀系数和优异的抗弯强度。Composites Part B: EngineeringCOMPRESSIVE RESISTANCE OF THIN-WALLED PULTRUDED GFRP PROFILES: THE ROLE OF DELAMINATION EXAMINED THROUGH EXPERIMENTS AND FE SIMULATIONSJosé Gonilha, João Alfredo de Lazzari, João Ramôa Correia, Nuno Silvestredoi:10.1016/j.compositesb.2024.111929薄壁拉挤GFRP型材的抗压性能:通过实验和有限元模拟研究分层的作用Significant efforts have been made in the last decades to develop design rules and guidelines for composite structures, meeting the increasing interest in pultruded glass fibre reinforced profiles (GFRP) by the construction industry. One aspect that has been difficult to address is the crushing resistance of these profiles, with previous research indicating that the design equations are not conservative, predicting much higher resistances than those obtained in experimental tests. This paper explores the possibility that crushing resistance is governed by tensile failure in the through-thickness direction of the laminates, by Poisson effect, and proposes modifications to a previously presented material damage model to account for this in finite element (FE) simulations. Compressive experimental tests were conducted in stub-column specimens, with 5 different open-section configurations, obtained from three different producers. The test results were compared to analytical and FE simulations, confirming that the former grossly overestimate the resistance, while the latter, with the proposed damage model, compare well with experimental results.在过去的几十年里,为了满足建筑行业对挤压玻璃纤维增强型材(GFRP)日益增长的兴趣,已经做出了重大的努力来制定复合结构的设计规则和指导方针。一个难以解决的方面是这些型材的抗压性,先前的研究表明,设计方程不是保守的,预测的阻力比实验测试中获得的阻力高得多。本文探讨了压碎阻力是由层压板在整个厚度方向上的拉伸破坏所控制的可能性,通过泊松效应,并提出了对先前提出的材料损伤模型的修改,以在有限元(FE)模拟中考虑到这一点。压缩实验测试在短柱试件中进行,从三个不同的生产商获得5种不同的开截面配置。将试验结果与分析和有限元模拟结果进行了比较,证实了前者严重高估了阻力,而后者采用所提出的损伤模型与试验结果比较吻合。Temperature-controlled in-situ construction of composition-tunable nanoparticle-decorated SOFC cathodes with enhanced oxygen reduction kinetics and CO2 toleranceChuangang Yao, Baixi Xia, Haixia Zhang, Haocong Wang, Wenwen Zhang, Xiaoshi Lang, Kedi Caidoi:10.1016/j.compositesb.2024.111917 具有增强氧还原动力学和二氧化碳耐受性的成分可调纳米颗粒装饰SOFC阴极的温控原位构建High oxygen reduction reaction (ORR) catalytic activity and CO2 resistance of the cathode are fundamental to the commercial application of solid oxide fuel cells (SOFCs). Therefore, we develop a temperature-driven reduction-reoxidation strategy to in-situ construct heterostructured perovskite cathodes decorated with different nanoparticles by controlling the reduction temperature. For (Pr0.4Sr0.6)0.95Co0.2Fe0.8-xNixO3-δ(PSCFN, x = 0.05, 0.1), reduction (@700 °C)-reoxidation results in the exsolution of a ComFenNi3-m-nO4 spinel phase on the perovskite scaffold surface, while reduction (@750 °C)-reoxidation leads to the formation of both ComFenNi3-m-nO4 spinel phase and NiO nanoparticles. The exsolution of these highly active species increases the quantity of oxygen reduction active sites and effectively suppresses Sr segregation. The simultaneous formation of ComFenNi3-m-nO4 spinel phase and NiO nanoparticles induces B-site ion vacancies in the main phase, therefore facilitates the formation of oxygen vacancies. Additionally, the presence of ComFenNi3-m-nO4/NiO/PSCFN heterointerfaces promotes oxygen adsorption and transfer. The strong interactions among ComFenNi3-m-nO4, NiO, and PSCFN significantly enhance the structural stability. At 800 °C, Reo2-PSCFN0.1 achieves an output performance of 1.12 W cm−2, representing a 36.6 % enhancement compared to PSCFN0.1. Moreover, the Rp of Reo2-PSCFN0.1 is merely 0.0186 Ω cm2, marking a 40.4 % decrease relative to PSCFN0.1. This temperature-driven reduction-reoxidation strategy shows great promise as a novel approach for creating high-performance IT-SOFC cathodes.我们开发了一种基于温度驱动的还原-氧化策略,通过控制还原温度来原位构建不同纳米粒子修饰的钙钛矿型阴极。对于(Pr0.4Sr0.6)0.95Co0.2Fe0.8-xNixO3-δ(PSCFN,x=0.05, 0.1),在700°C还原-氧化后,在钙钛矿骨架表面析出ComFenNi3-m-nO4尖晶石相;在750°C还原-氧化后,形成ComFenNi3-m-nO4尖晶石相和NiO纳米粒子。这些高度活性物种的析出增加了氧还原活性位点的数量,有效抑制了Sr的偏析。同时形成ComFenNi3-m-nO4尖晶石相和NiO纳米粒子会诱导主相中的B位离子空位,从而促进氧空位的形成。此外,ComFenNi3-m-nO4/NiO/PSCFN异质界面促进了氧的吸附和转移。复合物FenNi3-m-nO4、NiO和PSCFN之间的强相互作用显著提高了结构稳定性。在800°C时,Reo2-PSCFN0.1实现了1.12 W cm-2的输出性能,比PSCFN0.1提高了36.6%。此外,Reo2-PSCFN0.1的Rp仅为0.0186 Ω cm2,比PSCFN0.1降低了40.4%。这种由温度驱动的还原-氧化策略作为一种创建高性能IT-SOFC阴极的新型方法,具有巨大的潜力。The nitriding treatment of ternary nanofibers toward outstanding electromagnetic wave absorption performanceXiangwei Meng, Shuting Zhang, Meijie Yu, Chengguo Wangdoi:10.1016/j.compositesb.2024.111922 氮化处理使三元纳米纤维具有优异的电磁波吸收性能Beneficial from the high electrical conductivity and remarkable chemical stability, transition metal nitrides have attracted widespread attention in the employment of electromagnetic wave absorption. Toward this end, Fe4N/zirconium dioxide/carbon nanofibers composited absorber was triumphantly prepared by the combination of electrospinning, carbonization, and subsequent nitridation. After undergoing the nitriding treatment, the emergency of Fe4N with superior electromagnetic properties, the introduction of more defects and functional groups, and the synergistic effect between each component would dramatically intensify multiple loss mechanisms, optimize the impedance matching, and improve the wave absorbing properties. Ultimately, the ternary fibrous nanocomposite realized the minimum reflection loss of −63.7 dB at 12.5 GHz with corresponding matching thickness of 2.2 mm, and an ultrabroad bandwidth up to 7.0 GHz. Therefore, this work substantiated the promising potential of Fe4N in the practical application of microwave absorption, and shed light on the exploitation of a new generation metal nitrides-based wave absorbents.过渡金属氮化物由于具有较高的导电性和优异的化学稳定性,在电磁波吸收方面受到了广泛的关注。为此,通过静电纺丝、碳化、氮化等工艺,成功制备了Fe4N/二氧化锆/碳纳米纤维复合吸收剂。经过渗氮处理后,电磁性能优越的Fe4N的出现,引入更多的缺陷和官能团,以及各组分之间的协同作用,会极大地强化多种损耗机制,优化阻抗匹配,提高吸波性能。最终,该三元纤维纳米复合材料在12.5 GHz时实现了最小反射损耗- 63.7 dB,对应的匹配厚度为2.2 mm,超宽带高达7.0 GHz。因此,本研究证实了Fe4N在微波吸收实际应用中的巨大潜力,并为新一代金属氮基吸波剂的开发提供了思路。Damage mechanisms of SiC fibers and BN interphase in SiCf/SiC composites during NITE processYu Zhang, Xu Shen, Qin Ma, Shuang Mu, Shaoming Dong, Jinshan Yangdoi:10.1016/j.compositesb.2024.111923NITE过程中SiCf/SiC复合材料中SiC纤维和BN界面相损伤机理In this work, the mechanical behavior of NITE-SiCf/SiC composites, accompanied by the damage mechanisms of SiC fibers and BN interphase during NITE process, are investigated. The results show that the fracture characteristic of NITE-SiCf/SiC composite is transformed from quasi-ductile mode to brittle mode with the elevating temperature, as well as severe damage of SiC fiber and BN interphase. The damage of SiC fibers is originated from high temperature, sintering aids corrosion and matrix compression. High temperature and sintering aids diffusion lead to the grain growth and strength degradation of SiC fibers. The damage of BN interphase is caused by the sintering aids corrosion, mainly the reaction of Al2O3, and matrix compression. The stress distribution is simulated via finite element analysis proving that up to 17.5 GPa and 17.0 GPa stress originated from matrix shrinkage during sintering process is applied to the fiber and interphase respectively, making the fiber deformation and interphase fragmentation. The degraded fiber strength and destroyed interphase structure weaken the load-bearing capacity and crack deflection ability, causing degradation of mechanical properties and reliability of composites. This work helps to comprehensively understand and optimize the properties of SiCf/SiC composites prepared by NITE process.本文研究了NITE- sicf /SiC复合材料在NITE过程中的力学行为,以及SiC纤维和BN界面相的损伤机制。结果表明:随着温度的升高,NITE-SiCf/SiC复合材料的断裂特征由准韧性模式转变为脆性模式,SiC纤维和BN界面相损伤严重;SiC纤维的损伤主要来源于高温、烧结助剂腐蚀和基体压缩。高温和烧结助剂扩散导致SiC纤维晶粒长大和强度下降。BN界面相的破坏主要是由助烧剂腐蚀(主要是Al2O3的反应)和基体压缩引起的。通过有限元分析模拟应力分布,结果表明,在烧结过程中,纤维和界面分别受到17.5 GPa和17.0 GPa的应力,导致纤维变形和界面碎裂。纤维强度的退化和相间结构的破坏使复合材料的承载能力和裂纹挠曲能力减弱,导致复合材料的力学性能和可靠性下降。这项工作有助于全面了解和优化NITE工艺制备的SiCf/SiC复合材料的性能。Achieving Excellent Thermal Transport in Diamond/Cu Composites by Breaking Bonding Strength-Heat Transfer Trade-off Dilemma at the InterfaceGuo Chang, Shuang Zhang, Kaiyun Chen, Wei Zhang, Liang Li, Yongjian Zhang, Haoran Peng, Dongxiao Kan, Luhua Wang, Hailong Zhang, Wangtu Huodoi:10.1016/j.compositesb.2024.111925打破界面结合强度-传热权衡困境,实现金刚石/Cu复合材料的优异热传递The heat transport enhancement of diamond/Cu composites, a new generation of thermal management materials, is trapped in the bonding strength-heat transfer trade-off dilemma at the interface due to the noticeable difference in physical and chemical properties between Cu and diamond. Herein, we propose a new strategy combining ultrathin interface modification and low-temperature high-pressure (LTHP) sintering process to prepare the diamond/Cu composites. With a suitable coefficient of thermal expansion (CTE) of < 10 ppm/K, the obtained diamond/Cu composites exhibit an outstanding thermal conductivity (k) value of 763 W/m K, over 90% of the theoretical prediction of the differential effective medium (DEM) model. Meanwhile, using a lower diamond volume fraction (45% vs. 50%–70%), the k value is higher than those by conventional powder metallurgy, meaning a substantial reduction in the cost by reducing diamond filler content. For such a highly mismatched diamond/Cu interface, we maintain a high bonding strength by lowering the thermal stress damage while achieve a high thermal conductance (G) of 93.5 MW/m2 K by minimizing the heat transfer obstacles. The prepared interface structure is a diamond/TiC/CuTi2/Cu configuration, where the two possible heat transfer bottlenecks (the diamond/TiC interface and the TiC/CuTi2 interlayer) are no longer limiting factors on the overall interface. The successful resolution to the interfacial heat transfer problem is responsible for the superior thermal transport performance of the composites. This work deals with the critical challenge for the diamond/Cu composites and offers deep insight into the improvement mechanisms of thermal transfer. The proposed strategy can be generalized to the integration of highly mismatched interfaces widely present in other composites or thermal management systems.金刚石/Cu复合材料是新一代热管理材料,由于Cu与金刚石在物理和化学性质上的显著差异,其热传递增强在界面处陷入了结合强度-传热的权衡困境。在此,我们提出了一种结合超薄界面改性和低温高压烧结工艺制备金刚石/Cu复合材料的新策略。在合适的热膨胀系数(CTE) < 10 ppm/K时,金刚石/Cu复合材料的导热系数(K)为763 W/m K,超过微分有效介质(DEM)模型理论预测值的90%。同时,使用较低的金刚石体积分数(45% vs. 50%-70%), k值高于传统粉末冶金的k值,这意味着通过减少金刚石填料含量,可以大幅降低成本。对于这种高度不匹配的金刚石/Cu界面,我们通过降低热应力损伤来保持高结合强度,同时通过最小化传热障碍获得93.5 MW/m2 K的高导热系数(G)。制备的界面结构为金刚石/TiC/CuTi2/Cu结构,其中两个可能的传热瓶颈(金刚石/TiC界面和TiC/CuTi2夹层)不再是整个界面的限制因素。界面传热问题的成功解决是复合材料具有优良传热性能的重要原因。这项工作解决了金刚石/Cu复合材料面临的关键挑战,并为改善热传递机制提供了深入的见解。所提出的策略可以推广到广泛存在于其他复合材料或热管理系统中的高度不匹配界面的集成。Modeling and measurements of creep deformation in a ceramic fiber reinforced metal matrix compositeXu Kong, Yumin Wang, Qing Yang, Rui Yangdoi:10.1016/j.compositesb.2024.111926陶瓷纤维增强金属基复合材料蠕变的建模与测量This study proposes a novel analytical model for creep deformation in long brittle fiber-reinforced metal matrix composites. Unlike traditional creep models based on the steady-state creep expression of the creep behavior for the matrix in the composite, this model addresses the unsteady-state creep behavior. It also highlights the similarity between the governing equations for creep testing of the composite and stress relaxation testing of the unreinforced matrix. Owing to load transfer from the creeping matrix to the rigid fiber during the creep process, the matrix experiences decreasing stress and theoretically never reaches a steady state. Creep tests are conducted on a SiC fiber-reinforced Ti-6Al-2Sn-4Zr-2Mo-0.1Si alloy composite, within a stress range of 1100∼1350 MPa at 500 °C, with strain variation measured by an extensometer. Experimental results reveal significant discrepancies between the observed data and predictions based on steady-state creep assumptions. The differences between previous models and the proposed model are discussed using the experimental data.本文提出了一种新的长脆纤维增强金属基复合材料蠕变分析模型。与传统的基于复合材料中基体蠕变行为稳态蠕变表达式的蠕变模型不同,该模型处理的是非稳态蠕变行为。这也突出了复合材料蠕变试验的控制方程与未加筋基体应力松弛试验的相似之处。在蠕变过程中,由于载荷从蠕变基体转移到刚性纤维,使得基体应力逐渐减小,理论上不会达到稳定状态。对SiC纤维增强Ti-6Al-2Sn-4Zr-2Mo-0.1Si合金复合材料进行了蠕变试验,在500℃、1100 ~ 1350 MPa的应力范围内,用伸长计测量应变变化。实验结果显示观测数据与基于稳态蠕变假设的预测之间存在显著差异。利用实验数据讨论了该模型与以往模型的差异。Drug-free extracellular vesicles: A spatiotemporally controlled release engineering strategy for osteogenesis and anti-inflammatory niches in rotator cuff regenerationGuoyang Zhang, Dingyi Shi, Yiyao Wei, Mingqi Wang, Haohan Wang, Zhiqi Lin, Haihan Gao, Weixuan Lin, Hanyi Wang, Yonglin Guo, Yingyu Ge, Yi Lin, Yiwen Jiang, Xiaoyu Yan, Yuhao Kang, Liren Wang, Jinzhong Zhao, Weiyang Yingdoi:10.1016/j.compositesb.2024.111928无药物细胞外囊泡:一种时空控制释放工程策略,用于肌腱套再生中的成骨和抗炎小生境Natural small-molecule drugs have promising potential to promote tissue regeneration in various fields. Therefore, maximizing drug efficiency while minimizing potential side effects is imperative. Peiminine, a natural product extracted from natural Fritillaria, is one of small-molecule drugs in the field of bone regeneration due to its good bone-promoting and anti-inflammatory abilities. However, its application is limited by a lack of biological activity, poor biocompatibility at high concentrations, and difficulty in achieving long-term slow-release and therapeutic effects. Extracellular vesicles (EVs) produced by preconditioned cells are considered to have special biological functions, and their potential to further retain, buffer, and transmit drug effects and expand the therapeutic effect has been widely studied. Thus, our study provides a drug-free bioengineering strategy by preconditioning bone marrow mesenchymal stem cells (BMSC) with Peiminine, then EVs, secreted as Peim-EVs, were extracted and combined with a decellularized extracellular matrix (dECM). The final EVs-dECM system with a spatiotemporally controlled release system was formed. In vitro studies demonstrated that Peim-EVs solved the problem of Peiminine biocompatibility and exhibited osteogenic and anti-inflammatory effects, which may be related to PI3K/AKT, MAPK/NF-κB, and Hippo signaling pathways. An in vivo model of rotator cuff injury in rats also showed that EVs-dECM had a good effect on rotator cuff repair. Combined with engineering strategy, this study provides verification and scenario expansion for drug application, especially for drug-free strategies that retain the biological effects of drugs, and has broad significance.天然小分子药物在促进组织再生方面具有广阔的应用前景。因此,最大限度地提高药物效率,同时尽量减少潜在的副作用是势在必行的。贝母碱是从天然贝母中提取的天然产物,具有良好的促骨和抗炎作用,是骨再生领域的小分子药物之一。然而,由于缺乏生物活性,高浓度时生物相容性差,难以达到长期缓释和治疗效果,限制了其应用。细胞外囊泡(EVs)被认为具有特殊的生物学功能,其进一步保留、缓冲、传递药物效应和扩大治疗效果的潜力已被广泛研究。因此,我们的研究提供了一种无药物的生物工程策略,通过用Peiminine预处理骨髓间充质干细胞(BMSC),然后提取以peim - ev形式分泌的ev,并将其与脱细胞细胞外基质(dECM)结合。最终形成具有时空控制释放系统的ev - decm系统。体外研究表明,peim - ev解决了peim的生物相容性问题,并具有成骨和抗炎作用,这可能与PI3K/AKT、MAPK/NF-κB和Hippo信号通路有关。大鼠肩袖损伤的体内模型也显示ev - decm对肩袖修复有良好的效果。本研究结合工程策略,为药物应用特别是保留药物生物效应的无药策略提供了验证和场景拓展,具有广泛意义。Composites Science and TechnologyExperimental Study on the Influence of Optimised Automated Fibre Placement Processing Parameters on the Impact Response and Residual Flexural Strength of AS4/APC-2 LaminatesShafaq Shafaq, Matthew J. Donough, Binayak Bhandari, Andrew W. Phillips, Nigel A. St John, B. Gangadhara Prustydoi:10.1016/j.compscitech.2024.110945 优化自动铺放纤维工艺参数对AS4/APC-2层压板冲击响应及残余抗弯强度影响的实验研究This study explores automated fibre placement (AFP) for manufacturing impact-resistant carbon fibre (AS4) /PEEK (APC-2) laminates by modifying the in-situ consolidation parameters. However, manufacturing these laminates without compromising their mechanical properties is challenging owing to the synergistic effect of parameters. The results indicate that a fast deposition rate and high consolidation force are associated with improved impact resistance and a higher threshold energy for damage. Improvements in flexural strength (27.4%) and modulus (22.6%), are achieved in non-impacted specimens. Acoustic emission monitoring was conducted during flexural-after-impact test to correlate the internal damage with the mechanical performance of AS4/APC-2 composites. The experimental results indicated that a fast deposition rate combined with high consolidation force can withstand higher impact loads. The FAI test showed the highest residual flexural strength and stiffness under these parameters, as it effectively resisted low-velocity impact (LVI) damage. However, the slight trade-off observed in post-impact strength suggested the presence of resin-rich areas, which may affect the damage tolerance of the laminates.本研究通过修改原位固合参数,探索了用于制造抗冲击碳纤维(AS4) /PEEK (APC-2)层压板的自动化纤维放置(AFP)技术。然而,由于参数的协同效应,制造这些层压板而不损害其机械性能是具有挑战性的。结果表明,快速的沉积速率和高固结力与提高的抗冲击性能和更高的损伤阈值能有关。在非冲击样本中,抗弯强度(27.4%)和模量(22.6%)均有改善。通过对AS4/APC-2复合材料弯曲后冲击试验过程中的声发射监测,将AS4/APC-2复合材料的内部损伤与力学性能联系起来。实验结果表明,快速的沉积速率和较高的固结力可以承受较高的冲击载荷。在这些参数下,FAI测试显示出最高的残余抗弯强度和刚度,因为它有效地抵抗了低速冲击(LVI)损伤。然而,在冲击后强度中观察到的轻微权衡表明存在富含树脂的区域,这可能会影响层压板的损伤容限。Electromagnetic wave absorption and enhanced mechanical properties of magnetic self-healing metal shell microcapsules filled polymerQian Ren, Xiaoyu Zhang, Yiran Wu, Dawei Sun, Xin Zhangdoi:10.1016/j.compscitech.2024.110944 磁性自愈金属壳微胶囊填充聚合物的电磁波吸收及增强力学性能In this work, PUF/PU@IPDI (PPI) polymer shell microcapsules were synthesized through interfacial polymerization and in situ polymerization. Subsequently, a layer of metal Ni was plated on the surface of microcapsules to fabricate Ni/PUF/PU@IPDI (NPPI) composites. The results revealed that NPPI microcapsules exhibited superior thermal stability and mechanical properties, and NPPI-60 obtained the greatest strength (102.8 MPa). The minimum reflection loss (RL) value of the NPPI-20 composite was up to -32.8 dB at 5.5 mm and the corresponding effective absorption bandwidth (EAB) was 2.4 GHz. Additionally, the NPPI-10 composite displayed the highest healing efficiency (78.6% and 86.6% for the scratch depth and width, respectively), and the mechanical strength and fracture toughness of epoxy resin were enhanced by the addition of metal microcapsules. The core-shell structure established by electroless plating can endow self-healing microcapsules with outstanding mechanical characteristics as well as good wave absorption capability, indicating that NPPI composites have promising applications in the field of electromagnetic wave absorption and function and structure integration design of composites.本文通过界面聚合和原位聚合制备了PUF/PU@IPDI (PPI)聚合物壳微胶囊。随后,在微胶囊表面镀一层金属Ni,制备Ni/PUF/PU@IPDI (NPPI)复合材料。结果表明,NPPI微胶囊具有优异的热稳定性和力学性能,其中NPPI-60的强度最高(102.8 MPa)。在5.5 mm处,NPPI-20复合材料的最小反射损耗(RL)值高达-32.8 dB,相应的有效吸收带宽(EAB)为2.4 GHz。此外,NPPI-10复合材料的修复效率最高(划痕深度和宽度分别为78.6%和86.6%),金属微胶囊的加入提高了环氧树脂的机械强度和断裂韧性。通过化学镀建立的核壳结构可以使自愈微胶囊具有优异的力学特性和良好的吸波能力,这表明NPPI复合材料在电磁波吸收和复合材料功能结构一体化设计领域具有广阔的应用前景。来源:复合材料力学仿真Composites FEM

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