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【新文速递】2025年9月24日复合材料SCI期刊最新文章

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今日更新:Composite Structures 6 篇,Composites Science and Technology 1 篇

Composite Structures

Numerical investigation of the potential of double-double laminates to measure the interlaminar fracture toughness of multidirectional interfaces

Paulo Pereira, Federico Danzi, Pedro Pinto, Torquato Garulli, Carolina Furtado

doi:10.1016/j.compstruct.2025.119666

测量多向界面层间断裂韧性的双-双层板电位数值研究

The suitability of Double-Double (DD) laminates to assess the interlaminar fracture toughness of multidirectional interfaces in mode I and mode II is investigated numerically through the use of the 3D-Virtual Crack Closure Technique (3D-VCCT)-based and crack propagation ana lyses. The effects of ply thickness, mis match angle, and stacking sequence on the width-wise Energy Release Rate (ERR) distributions are investigated. Four thin-ply DD stacking sequences are an alyzed, revealing low mode mixity and spurious off-axis reaction forces, thanks to laminate homogenization. The stacking sequence [ − Φ / Ψ / Φ / − Ψ ] 10 / / [ Φ / − Ψ / − Φ / Ψ ] 10 , named Staggered 1, is identified as the most promising configuration, with a minimal spurious mode and reduced crack curvature. Further an alysis of ply thickness showed that lower ply thickness and more repetitions improve suitability for interlaminar fracture toughness measurements. Evaluation of Staggered 1 laminate with Ψ = 0 ∘ over several mis match angles (0°–45°) indicated negligible mode mixity, crack curvature, and crack skewness during crack propagation. The findings suggest that DD laminates are promising for assessing interlaminar toughness in multidirectional interfaces if appropriate ply thickness and sublaminate repetitions are used.

采用基于三维虚拟裂纹闭合技术(3D-VCCT)和裂纹扩展分析的方法,对双层(DD)层压板在I型和II型多向界面层间断裂韧性评估中的适用性进行了数值研究。研究了层厚、错配角和堆叠顺序对宽度方向能量释放率(ERR)分布的影响。分析了四种薄层DD堆叠序列,揭示了由于层压均匀化而产生的低模式混合和伪离轴反作用力。堆叠序列[−Φ / Ψ / Φ /−Ψ] 10 / / [Φ /−Ψ /−Φ / Ψ] 10,被认为是最有希望的配置,具有最小的杂散模式和减小的裂缝曲率。进一步分析表明,较低的厚度和较多的重复次数提高了层间断裂韧性测量的适用性。对Ψ = 0°下多个失配角(0°-45°)的交错1层压板的评估表明,在裂纹扩展过程中,模态混合、裂纹曲率和裂纹偏度可以忽略不计。研究结果表明,如果采用适当的层厚和次层重复次数,DD层合板有望用于评估多向界面的层间韧性。


Efficient multi-objective optimization of composite microstructures for thermal protection systems

Idan Distelfeld, Shmuel Osovski

doi:10.1016/j.compstruct.2025.119679

热防护系统复合微结构的高效多目标优化

This paper presents a surrogate model-based approach for multi-objective optimization of composite representative volume elements under thermo-mechanical loading. The RVE architecture, inspired by metallic honeycomb structures with inclined fibers, allows tailoring the anisotropy of thermal and mechanical properties. A parametric model is an alyzed using Finite Element An alysis with periodic boundary conditions and homogenization theory. The 10-dimensional design space is sampled using Latin Hypercube Sampling, and simulated to calculate effective elastic mod uli and thermal conductivity. This dataset is used to train a shallow neural network (SNN) model, offering computational efficiency and rapid exploration of complex design spaces. The SNN is employed in a multi-objective optimization process using the NSGA-II algorithm, allowing simultaneous optimization of elastic properties, thermal conductivity, and density. This reveals trade-offs between competing objectives, with resulting Pareto frontiers providing crucial information for informed design decisions. The method demonstrates a fast, accurate, and flexible approach for optimizing composite architectures. Combining advanced modeling techniques with efficient optimization algorithms, this work contributes to developing lightweight, multifunctional materials for aerospace, automotive, and other demanding applications. The approach has significant implications for optimizing composite materials in complex structures, advancing the state-of-the-art in composite materials research and providing a powerful tool for high-performance material design.

提出了一种基于代理模型的复合材料代表性体积元热-机械载荷多目标优化方法。RVE建筑的灵感来自金属蜂窝结构和倾斜纤维,可以定制热性能和机械性能的各向异性。采用周期边界条件和均匀化理论对参数化模型进行了有限元分析。采用拉丁超立方采样法对10维设计空间进行采样,并对其进行模拟,计算有效弹性模量和导热系数。该数据集用于训练浅层神经网络(SNN)模型,提供计算效率和对复杂设计空间的快速探索。SNN采用NSGA-II算法进行多目标优化,可同时优化弹性性能、导热性和密度。这揭示了竞争目标之间的权衡,由此产生的帕累托边界为明智的设计决策提供了关键信息。该方法为优化复合体系结构提供了一种快速、准确、灵活的方法。将先进的建模技术与高效的优化算法相结合,这项工作有助于开发用于航空航天、汽车和其他苛刻应用的轻质多功能材料。该方法对复杂结构复合材料的优化、复合材料研究的进步以及高性能材料的设计都具有重要意义。


Influence of post-processing on the Mode I and Mode II static fracture toughness of additively manufactured carbon fiber composites

Zane Forbes, Johannes Reiner, Xiaobo Yu, Garth Pearce, Mathew W. Joosten

doi:10.1016/j.compstruct.2025.119664

后处理对增材碳纤维复合材料I型和II型静态断裂韧性的影响

The layer-by-layer fabrication process of additively manufactured (AM) composites can introduce interlaminar defects that may impact interlaminar fracture toughness. This study investigates the effect of post-processing on the interlaminar fracture toughness of AM continuous carbon fibre/polyamide composites produced via fused filament fabrication. Post-processing samples in an oven at 150 °C enhanced the initiation interlaminar fracture toughness by 9.12 % in Mode I and 17.94 % in Mode II, while the propagation interlaminar fracture toughness increased by 18.14 % and 9.37 %, respectively. Optical microscopy revealed that post-processing reduced the void content, from 6.24 % to 1.12 %. Scanning electron microscopy highlighted that the fracture surfaces of the post-processed samples showed a reduction in void-related defects. These findings demonstrate that the interlaminar fracture toughness of AM composites can be improved through post-processing consolidation, which enhances the materials resistance to crack initiation and propagation.

增材制造(AM)复合材料的逐层制备工艺会引入层间缺陷,影响层间断裂韧性。研究了后处理对增材制造碳纤维/聚酰胺连续复合材料层间断裂韧性的影响。在150 °C的烘箱中处理后的样品,在模式I和模式II下,初始层间断裂韧性分别提高了9.12 %和17.94 %,而在模式II下,扩展层间断裂韧性分别提高了18.14 %和9.37 %。光学显微镜显示,后处理降低了孔隙率,从6.24 %降至1.12 %。扫描电镜显示,后处理样品的断口表面显示与空洞相关的缺陷减少。研究结果表明,通过后处理固结可以提高增材复合材料的层间断裂韧性,增强材料抗裂纹萌生和扩展的能力。


Stress-gradient model for tensile damage in orthotropic materials

Franziska Seeber, Ani Khaloian-Sarnaghi, Elena Benvenuti, Fabian Duddeck, Jan-Willem van de Kuilen

doi:10.1016/j.compstruct.2025.119674

正交异性材料拉伸损伤的应力梯度模型

Reliable finite element simulation of orthotropic-dependent failure mechanis ms is crucial for understanding the mechanical behavior and optimizing engineered composites and fiber-based materials. Such materials behave brittle under tension and strongly depend on the orthotropic material orientation. Existing non-local models can reproduce brittle fracture for isotropic materials but, in most cases, they are based on the equivalent strain concept for damage initiation, which is unsuitable for orthotropic materials. This contribution introduces a stress-based non-local damage model enhanced with an implicit gradient formulation of the failure criteria. A localizing non-local length is assumed to avoid any pathological broadening of the damage band. The methodology introduces direction-dependent damage variables driven by non-local stress-based damage criteria and can thus distinguish different failure modes. The verification and validation are shown on numerical and experimental benchmark examples. The implicit gradient-based non-local damage approach allows mesh-independent results. Furthermore, it does not require a priori known crack paths and makes it possible to simulate complex failure modes. Perspectively, its effective implementation in the commercial software Abaqus and combination with other constitutive laws, e.g. to account for plasticity or moisture, make it an attractive tool for describing the mechanical material behavior of orthotropic materials, such as wood and fiber-composites.

可靠的正交各向异性相关破坏机制的有限元模拟对于理解力学行为和优化工程复合材料和纤维基材料至关重要。这种材料在拉伸作用下表现为脆性,并且强烈依赖于材料的正交异性取向。现有的非局部模型可以再现各向同性材料的脆性断裂,但在大多数情况下,它们是基于等效应变的损伤起裂概念,这并不适合于正交各向异性材料。这一贡献引入了一种基于应力的非局部损伤模型,增强了失效准则的隐式梯度公式。假设一个局部的非局部长度以避免任何病理性的损伤带拓宽。该方法引入了由非局部应力损伤准则驱动的方向相关损伤变量,从而可以区分不同的破坏模式。通过数值算例和实验基准算例进行了验证和验证。隐式基于梯度的非局部损伤方法允许网格无关的结果。此外,它不需要先验已知的裂纹路径,使模拟复杂的破坏模式成为可能。从长远来看,它在商业软件Abaqus中的有效实现以及与其他本构律的结合,例如,考虑塑性或水分,使其成为描述正交异性材料(如木材和纤维复合材料)的机械材料行为的有吸引力的工具。


Data-driven failure criteria prediction in composite wing boxes using machine learning

Dario Magliacano, Vincenza Tufano, Annalisa Letizia, Bernardo Sessa, Matteo Filippi

doi:10.1016/j.compstruct.2025.119675

基于机器学习的复合材料翼盒数据驱动故障准则预测

Modern transport aircraft exploit composite wing-box architectures to maximize strength-to-weight efficiency, yet the through-thickness damage states that govern air-worthiness remain difficult to quantify by closed-form an alysis. A fully labeled benchmark data set, comprising 1017 finite-element (FE) simulations of a Cirrus-class carbon-fiber wing-box (nine undamaged cases plus 1008 damage scenarios obtained by combining 28 intralaminar damage locations with four severity levels for each of nine orthotropic materials) is therefore generated. Five classical failure criteria (Max-Stress, Tsai–Wu, Tsai–Hill, Hashin and Christensen) are evaluated at the most-stressed element and adopted as supervised-learning targets. Two regression surrogates, Random Forest (RF) ensembles and Support Vector Regression (SVR), are trained on the material-property vector and damage descriptors. A material-wise leave-one-out (LOO) cross-validation strategy demonstrates that the RF model attains a root-mean-square error RMSE = 0.076 for the Hashin index, while preserving RMSE ≤ 0.15 on the Max-Stress index. The resulting RF surrogate furnishes near-instant predictions of composite failure indices and provides a reliable machine-learning benchmark for operational wing-box health assess ment.

现代运输机采用复合材料翼盒结构来最大限度地提高强度重量比效率,但控制适航性的全厚度损伤状态仍然难以通过封闭形式分析来量化。因此,生成了一个完全标记的基准数据集,包括1017个cirruss级碳纤维翼盒的有限元(FE)模拟(9个未损坏情况加上1008个损坏情况,这些情况是通过结合28个层内损伤位置,每种材料的四个严重级别获得的)。在最大应力单元上评估了5个经典失效准则(Max-Stress、Tsai-Wu、Tsai-Hill、Hashin和Christensen),并将其作为监督学习目标。两个回归代理,随机森林(RF)集成和支持向量回归(SVR),在材料属性向量和损伤描述符上进行训练。材料方面的留一(LOO)交叉验证策略表明,RF模型在Hashin指数上获得均方根误差RMSE = 0.076,而在最大应力指数上保持RMSE≤0.15。由此产生的RF代理提供了近乎即时的复合故障指数预测,并为操作翼箱健康评估提供了可靠的机器学习基准。


Manufacture, process simulation, modelling and testing of thick-walled thermoset fibre-polymer composite laminates — A review

Richard Protz, Eckart Kunze, Tim Luplow, Linus Littner, Jonas Drummer, Sebastian Heimbs, Marc Kreutzbruck, Bodo Fiedler, Maik Gude

doi:10.1016/j.compstruct.2025.119678

厚壁热固性纤维聚合物复合层压板的制造、工艺模拟、建模和试验。综述

Thick-walled thermoset fibre-reinforced polymer (FRP) composites present unique challenges across their manufacturing, simulation, modelling, and testing processes. This paper provides a comprehensive overview of the current challenges and research needs associated with thick-walled FRP, particularly in light of their growing relevance in demanding application domains, such as wind energy. It is important to emphasise that the designation of a laminate as thick-walled is determined not solely by its nominal thickness, but also by the direction of the applied load. In particular, laminates subjected to compressive loading are typically considered thick-walled from a wall thickness of 4 mm or greater. While conventional manufacturing techniques remain applicable to thick-walled FRPs, process adaptations, such as adjusted curing cycles or alternative curing methods, are necessary to mitigate manufacturing defects, e.g. residual stresses induced by inhomogeneous curing due to local temperature overshoot. Modelling of the curing process and accurate prediction of residual stress development remain key areas of ongoing research with significant gaps in understanding. The influence of the wall thickness can also be seen in quasi-static and impact tests. Self-heating must be taken into account in fatigue tests and must be incorporated into future guidelines for the design of thick-walled FRP structures. While well-established non-destructive testing (NDT) techniques are generally applicable, their effectiveness is reduced with increasing laminate thickness due to limitations in resolution. The findings underscore the need for continued interdisciplinary efforts to refine processing and evaluation methods for thick-walled FRP composites.

厚壁热固性纤维增强聚合物(FRP)复合材料在其制造、模拟、建模和测试过程中提出了独特的挑战。本文全面概述了当前与厚壁FRP相关的挑战和研究需求,特别是考虑到它们在风能等苛刻应用领域的日益相关性。需要强调的是,厚壁层压板的名称不仅取决于其标称厚度,还取决于所施加载荷的方向。特别是,承受压缩载荷的层压板通常被认为是厚壁的,壁厚为4毫米或更大。虽然传统的制造技术仍然适用于厚壁frp,但工艺调整,如调整固化周期或替代固化方法,对于减轻制造缺陷是必要的,例如,由于局部温度超调而引起的不均匀固化引起的残余应力。固化过程的建模和残余应力发展的准确预测仍然是正在进行的研究的关键领域,在理解上存在重大差距。在准静态和冲击试验中也可以看到壁厚的影响。疲劳试验中必须考虑到自热,并且必须将其纳入厚壁FRP结构设计的未来指南中。虽然成熟的无损检测(NDT)技术普遍适用,但由于分辨率的限制,其有效性随着层压厚度的增加而降低。研究结果强调需要继续跨学科的努力,以完善加工和评价方法的厚壁FRP复合材料。


Composites Science and Technology

Cellulose Nanofibers-Enabled Interfacial Engineering for Thermally Conductive Composites with Superior Mechanical Durability

Wen-yan Wang, Yan-ji Yin, Yuan-chao Jiang, Rui Han, Min Nie

doi:10.1016/j.compscitech.2025.111390

 

具有优异机械耐久性的导热复合材料的纤维素纳米纤维界面工程

Cellulose nanofibers (CNFs), derived from renewable biomass, offer exceptional mechanical properties, a high aspect ratio, and abundant surface hydroxyl groups, making them highly attractive for polymer composite functionalization. In this study, CNFs are employed as both dispersing and reinforcing agents to address the dual challenges of filler aggregation and poor interfacial adhesion in nylon-based thermally conductive composites. By leveraging their strong hydrogen bonding capability, CNFs not only enable the uniform dispersion of boron nitride (BN) fillers in aqueous systems but also facilitate the construction of robust interfacial networks within the polymer matrix. Using a simple vacuum-assisted filtration and compression molding strategy, we fabricated laminated composites featuring highly aligned BN structures. This unique architecture promotes the formation of efficient thermal pathways, resulting in an in-plane thermal conductivity of 4.5 W·m-1·K-1 at 24.5 wt% BN—an 1857% enhancement over pure nylon. Simultaneously, the CNF-induced interfacial reinforcement leads to excellent mechanical strength and fatigue resistance, with the composite retaining 92% of its thermal conductivity and 85% of its tensile strength after 100,000 bending cycles. These findings demonstrate the significant potential of CNF-assisted interfacial engineering for developing high-performance, thermoplastic-based thermal management materials suitable for flexible electronics and other advanced applications.

纤维素纳米纤维(CNFs)来源于可再生生物质,具有优异的机械性能、高长径比和丰富的表面羟基,使其在聚合物复合功能化方面具有很高的吸引力。在这项研究中,CNFs被用作分散剂和增强剂,以解决尼龙基导热复合材料中填料聚集和界面粘附不良的双重挑战。CNFs利用其强大的氢键能力,不仅使氮化硼(BN)填料在水体系中均匀分散,而且有助于在聚合物基体中构建坚固的界面网络。使用简单的真空辅助过滤和压缩成型策略,我们制造了具有高度排列BN结构的层压复合材料。这种独特的结构促进了高效热通道的形成,在24.5% wt% bn时,其面内导热系数为4.5 W·m-1·K-1,比纯尼龙提高了1857%。同时,cnf诱导的界面增强带来了优异的机械强度和抗疲劳性能,在10万次弯曲循环后,复合材料保持了92%的导热系数和85%的抗拉强度。这些发现证明了cnf辅助界面工程在开发适用于柔性电子和其他先进应用的高性能热塑性热管理材料方面的巨大潜力。



 

来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalSystem疲劳断裂复合材料光学航空航天汽车建筑电子裂纹理论材料控制试验
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【新文速递】2025年9月10日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 3 篇International Journal of Solids and StructuresBuckling behavior modeling and prevention in hydro-pressing forming process of high strength metal tubesRuihua Chu, Xiao-Lei Cui, Jiuqiang He, Shijian Yuandoi:10.1016/j.ijsolstr.2025.113655 高强度金属管液压成形屈曲行为建模及预防Tube hydro-pressing is an advanced hydroforming process with less-loading requirements suitable for manufacturing tubular components of high strength metals such as dual-phase steels and titanium alloys. However, the thin-walled tube blank is prone to be buckling under bending moment and circumferential compressive stress during the hydro-pressing process. To prevent this defect, an ana lytical model of critical supporting pressure was firstly established based on energy theory during the corner filling process. The factors influencing critical supporting pressure were an alyzed to understand the characteristics in hydro-pressing for different tube materials. Subsequently, hydro-pressing experiments were conducted on two typical high strength metal tubes: DP590 dual-phase steel and TA18 titanium alloy. The experimental results verified the accuracy of the an alytical model and revealed the influence of the material on the critical supporting pressure. It is shown that the critical supporting pressure required for forming is positively related to strength coefficient (K) and negatively related to strain hardening exponent (n) and diameter-thickness ratio (d0/t) of the tube, but has little dependence on height-to-width ratio (h/w) of cross-section. For the two typical tubes, the critical supporting pressure required for forming was 4.11 MPa and 1.36 MPa, respectively. Stable corner filling can proceed without any buckling instability defects when the supporting pressure in the forming process is higher than the critical value mentioned above. These results provide theoretical support for the development and application of the tube hydro-pressing process.管材液压成形是一种载荷要求较低的先进液压成形工艺,适用于制造双相钢和钛合金等高强度金属的管材部件。然而,薄壁管坯在液压成形过程中,在弯矩和周向压应力作用下容易发生屈曲。为了防止这一缺陷,首先基于能量理论建立了角部充填过程中临界支撑压力的解析模型。分析了影响临界支撑压力的因素,了解了不同管材的液压特性。随后,对DP590双相钢和TA18钛合金两种典型高强度金属管进行了液压压制实验。实验结果验证了分析模型的准确性,揭示了材料对临界支撑压力的影响。结果表明:成形所需临界支撑压力与管材强度系数K呈正相关,与应变硬化指数n和管材径厚比d0/t呈负相关,而与管材截面高宽比h/w关系不大;两种典型管材成形所需的临界支撑压力分别为4.11 MPa和1.36 MPa。当成形过程中的支撑压力高于上述临界值时,可以进行稳定的边角填充,不存在屈曲失稳缺陷。研究结果为管材液压成形工艺的开发和应用提供了理论支持。Journal of the Mechanics and Physics of SolidsMacro- and Micro-Mechanical Perspectives on Creep-Fatigue Interaction in Type 316L Stainless SteelFan Wu, Yang Liu, Huayue Zhang, Christos Skamniotis, Umer Masood Chaudry, Gareth Douglas, Joe Kelleher, Andrew Wis bey, Mike Spindler, Marc Chevalier, Bo Chendoi:10.1016/j.jmps.2025.106353 316L型不锈钢蠕变-疲劳相互作用的宏观和微观力学观点Creep-fatigue of Type 316L stainless steel under asymmetric waveforms (specifically slow tension-fast compression, S-F, and fast tension-slow compression, F-S) has been understudied, despite its significant implications as demonstrated in this work. This study bridges macro- and micro-mechanical perspectives through a combined approach, involving high-temperature testing, scanning electron microscopy, X-ray computed tomography, neutron diffraction, and crystal plasticity modelling. Macro-mechanical tests revealed distinct deformation behaviours under S-F and F-S waveforms with and without a 1-hour tensile dwell at 550°C, with S-F reducing lifespan in both fatigue and creep-fatigue conditions. Post-mortem ana lyses revealed distinct fracture morphologies induced by tensile dwell, with creep-fatigue S-F specimen exhibiting more pronounced intergranular-dominant fracture and higher internal defect volume. It also exhibited the highest number fraction of medium-sized (10-40 μm) microcracks, which correlates with its shortest fatigue life and more creep damage accumulation. Higher grain-level deformation incompatibility was observed during tensile dwell in the S-F load waveform. Crystal plasticity modelling revealed that the higher tensile stress amplitudes during S-F loading stem from increased dislocation density, with average densities at peak tensile strain during the saturation cycle reaching 186 μm⁻² for S-F and 147 μm⁻² for F-S waveforms. These findings establish a strong link between macroscopic and microscopic behaviours under asymmetric loading, emphasising the potential of S-F waveforms for cost-effective creep-fatigue experiment design. Furthermore, for the asymmetric waveforms studied, creep-fatigue life assess ment using the ductility exhaustion method demonstrate greater accuracy than those based on the time fraction method.316L型不锈钢在不对称波形(特别是慢张-快压缩,S-F,和快张-慢压缩,F-S)下的蠕变疲劳还没有得到充分的研究,尽管它在这项工作中证明了它的重要意义。本研究通过结合高温测试、扫描电子显微镜、x射线计算机断层扫描、中子衍射和晶体塑性建模等方法,将宏观和微观力学观点联系起来。宏观力学测试显示,在550°C下,无论是否有1小时的拉伸停留,S-F和F-S波形下的变形行为都是明显的,S-F降低了疲劳和蠕变疲劳条件下的寿命。尸检分析揭示了拉伸驻留引起的明显断裂形态,蠕变疲劳S-F试样表现出更明显的晶间断裂和更高的内部缺陷体积。中等尺寸(10 ~ 40 μm)微裂纹数量最多,其疲劳寿命最短,蠕变损伤积累较多。在S-F载荷波形中,拉伸停留期间观察到较高的晶粒级变形不相容。晶体塑性模型显示,S-F加载过程中较高的拉伸应力振幅源于位错密度的增加,在饱和周期中,S-F波形的峰值拉伸应变平均密度达到186 μm⁻²,F-S波形的平均密度达到147 μm⁻²。这些发现建立了不对称载荷下宏观和微观行为之间的紧密联系,强调了S-F波形在经济有效的蠕变疲劳实验设计中的潜力。此外,对于所研究的非对称波形,使用延性耗尽法进行蠕变疲劳寿命评估比基于时间分数法的评估具有更高的准确性。International Journal of PlasticityUltra-low temperature mechanical response of VCoNi medium-entropy alloy with unprecedented high strength and ductilityTae Jin Jang, Min Young Sung, Gunjick Lee, Hahun Lee, Jun Ho Lee, Alireza Zargaran, Young-Kyun Kim, Zhiming Li, Young-Sang Na, Seok Su Sohndoi:10.1016/j.ijplas.2025.104473 具有空前高强度和高塑性的VCoNi中熵合金的超低温力学响应This work reports on the unprecedented high tensile strength and ductility of single-phase VCoNi medium-entropy alloys (MEAs) at liquid helium temperature (4.2 K) and reveals the effects of grain size on strength, strain-hardening capability, and discontinuous plastic flow (DPF) behavior at 4.2 K. The fine-grained VCoNi MEA with an average grain size of 2.2 μm exhibits exceptional yield strength of 1386 MPa and tensile stress of 1845 MPa at a high elongation of 43%. The Hall–Petch (H–P) relationship at 4.2 K for the VCoNi MEA was established for the first time, demonstrating that the yield strength enhancement with decreasing temperature primarily originates from a reduction in dislocation width, leading to an exceptionally high solid-solution strengthening contribution of 782 MPa. In addition to planar slip, nano-twinning and stacking faulting were activated at 4.2 K upon plastic deformation, contributing to a sustained strain-hardening capability. The restricted mobility of screw dislocations at 4.2 K suppresses dynamic recovery, facilitating dislocation proliferation and further enhancing strain hardening. In terms of DPF behavior, characterized by abrupt serrations in the stress-strain curves, fine-grained specimens exhibit more pronounced DPF due to the rapid accumulation of geometrically necessary dislocations. However, the maximum stress drop prior to plastic instability remains similar across all grain sizes, suggesting that dislocation density is the primary factor governing DPF behavior. These findings provide important insights into the development and mechanistic understanding of ultrastrong and ductile alloys for applications at extremely low temperatures.本文报道了单相VCoNi中熵合金(MEAs)在液氦温度(4.2 K)下具有前所未有的高拉伸强度和延展性,并揭示了晶粒尺寸对强度、应变硬化能力和不连续塑性流动(DPF)行为的影响。平均晶粒尺寸为2.2 μm的细晶VCoNi MEA屈服强度为1386 MPa,拉伸应力为1845 MPa,延伸率高达43%。首次建立了VCoNi MEA在4.2 K时的Hall-Petch (H-P)关系,表明随着温度的降低,屈服强度的增强主要来自位错宽度的减小,从而导致了极高的固溶强化贡献,达到782 MPa。除了平面滑移外,在4.2 K的塑性变形下,纳米孪晶和堆积断层也被激活,这有助于持续的应变硬化能力。4.2 K时螺位错的受限迁移抑制了动态恢复,促进了位错扩散,进一步增强了应变硬化。在DPF行为方面,其特征是应力-应变曲线上的突然锯齿,细晶试样由于几何上必要的位错的快速积累而表现出更明显的DPF。然而,塑性失稳前的最大应力降在所有晶粒尺寸中仍然相似,这表明位错密度是控制DPF行为的主要因素。这些发现为在极低温下应用的超强和延展性合金的开发和机理理解提供了重要的见解。Thin-Walled StructuresS mooth reconstruction of blade profile from data points and its characterizationKadir Kirandoi:10.1016/j.tws.2025.113846基于数据点的叶片型线平滑重构及其特征In the current paper, reconstruction and characterization procedures for the blade profile data points are comprehensively presented. For the reconstruction, a single C2-continuous fair Bezier curve fitting algorithm is developed. This algorithm is based on the nonlinear least squares fitting method and it performs fitting and fairing processes concurrently, which eliminates the need for post processing of the reconstructed blade profile. Thus, we are able to accurately represent large number of blade profile data points with maximum 14 control points of a Bezier curve. On the other hand, in the characterization procedure, the reconstructed blade profile camber line, radius distribution and fundamental design parameters (i.e., inlet metal, outlet metal and stagger angles, and chord length) are computed. The implementations and validations of the proposed procedures are completed with data points of various reference blade and airfoil profiles, and a worn aero-engine blade profile data points achieved via a coordinate measuring machine (CMM). The results have shown that the proposed procedures along with their algorithms are quite successful, practical, and powerful for the blade profile reconstruction and characterization. They have great potential as useful tools for the design, ana lysis, optimization, inspection, and manufacturing of the blades.在本文中,全面介绍了叶片轮廓数据点的重建和特征化程序。对于重建,开发了一种基于非线性最小二乘拟合方法的单 C2 连续光滑贝塞尔曲线拟合算法。该算法同时执行拟合和光顺过程,从而无需对重建的叶片轮廓进行后处理。因此,我们能够用最多 14 个贝塞尔曲线控制点准确表示大量叶片轮廓数据点。另一方面,在特征化程序中,计算了重建叶片轮廓的弯度线、半径分布和基本设计参数(即进口金属角、出口金属角和安装角以及弦长)。通过各种参考叶片和翼型轮廓的数据点以及通过坐标测量机(CMM)获得的磨损航空发动机叶片轮廓数据点,完成了所提出程序的实现和验证。结果表明,所提出的程序及其算法在叶片轮廓重建和特征描述方面非常成功、实用且强大。它们作为叶片设计、分析、优化、检测和制造的有用工具具有巨大潜力。Vibration an alysis of partially cracked thin orthotropic cylindrical shells with linearly and quadratically varying thickness: An ana lytical approachRahul Singh, Ankur Gupta, Nitin Kumar Jaindoi:10.1016/j.tws.2025.113939 线性和二次变厚正交各向异性薄圆柱壳部分开裂振动分析:一种解析方法This study presents an an alytical model for the free vibration an alysis of thin orthotropic cylindrical shells featuring linearly and quadratically varying thickness. The shell is assumed to have a length significantly greater than its other dimensions, and a s mall mid-span surface crack is considered to evaluate its impact on dynamic behaviour. The governing equations of motion are derived using classical shell theory and simplified using the Donnell–Mushtari–Vlasov (DMV) formulation to incorporate the effects of thickness variation. Crack-induced stiffness reduction is modelled using crack compliance coefficients based on the Line Spring Model (LS M), accounting for both axial and circumferential crack orientations. The influence of variable thickness on structural stiffness and vibration characteristics is explicitly addressed. A closed-form solution for simply supported and clamped boundary conditions is obtained via Hamilton’s principle and separation of variables. The an alytical results are validated through comparison with existing literature. A comprehensive parametric study is conducted to assess the effects of thickness gradients, crack size and position, and orthotropic material properties on the fundamental natural frequency.本文建立了具有线性和二次变化厚度的正交各向异性薄圆柱壳的自由振动分析模型。假设壳的长度明显大于其其他尺寸,并考虑一个小的跨中表面裂纹来评估其对动力性能的影响。利用经典壳体理论推导了运动控制方程,并利用Donnell-Mushtari-Vlasov (DMV)公式进行了简化,以考虑厚度变化的影响。采用基于线弹簧模型(LS M)的裂纹柔度系数,考虑轴向和周向裂纹方向,对裂纹诱导的刚度降低进行建模。明确讨论了变厚度对结构刚度和振动特性的影响。利用Hamilton原理和分离变量法,得到了简支固支边界条件的封闭解。通过与已有文献的比较,验证了分析结果。对厚度梯度、裂纹尺寸和位置以及正交各向异性材料特性对基频的影响进行了综合参数化研究。Experimental and Numerical Investigation of Vibration Characteristics of X-Frame CFRP Sandwich PlatesMin Tang, Longjun Chen, Weimin Jiang, Zhikang Liu, Jiayi Liu, Wei Huangdoi:10.1016/j.tws.2025.113942x -框架CFRP夹芯板振动特性试验与数值研究The vibration performance of the X-frame carbon fiber reinforced polymer (CFRP) sandwich plates was studied by experiments and simulations in this paper. The research focused on the influences of foam filling, relative density (RD) and designed parameters of the core on the modal characteristic and surface mean quadratic velocity of the plates. Firstly, the vibration modals and mean quadratic velocity of X-frame sandwich plates with or without foam-filled were measured in vacuum as well as underwater through experiments. Then, numerical simulation ana lysis was carried out, and the results by numerical simulation an alysis were highly consistent with the experimental results. Finally, the vibration performance of X-frame sandwich plates with different parameters was researched by the validated numerical simulation ana lysis. The results of experiments indicated that filling low-density foam into the core could increase the natural frequencies slightly and reduce the mean quadratic velocity at the natural frequencies of the plates. The low-density foam played a role in peak shaving. Improving the relative density of the core increased the natural frequencies significantly and reduced the overall mean quadratic velocity of the plates. The influence of parameter variations on vibration performance was discussed based on the favorable agreement observed between the results by experiment and simulation. The simulation results showed that the 45° X-frame sandwich plate had the s mallest surface mean quadratic velocity compared with the other three designed angles including 40°, 55°, and 70° when the relative density of the core was same.通过实验和仿真研究了x -框架碳纤维增强聚合物(CFRP)夹层板的振动性能。研究了泡沫填充、相对密度和芯材设计参数对板的模态特性和表面平均二次速度的影响。首先,通过实验测量了x -框架夹层板在真空和水下的振动模态和平均二次速度。然后进行数值模拟分析,数值模拟分析结果与实验结果高度吻合。最后,通过验证的数值模拟分析,研究了不同参数下x -框架夹层板的振动性能。实验结果表明,在芯内填充低密度泡沫可以略微提高板的固有频率,降低板在固有频率处的平均二次速度。低密度泡沫起到了剃峰的作用。提高堆芯的相对密度显著提高了固有频率,降低了整体平均二次速度。在实验结果与仿真结果吻合良好的基础上,讨论了参数变化对振动性能的影响。仿真结果表明,在堆芯相对密度相同的情况下,45°x -框架夹心板的表面平均二次速度比40°、55°和70°夹心板设计角度最小。来源:复合材料力学仿真Composites FEM

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