【新文速递】2024年5月25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，International Journal of Plasticity 1 篇

International Journal of Solids and Structures

Unraveling elastochemical effects in microstructural evolution of Al-Cu-Ni system through DFT-informed multi-phase field simulations

Sachin Poudel, Nele Moelans, Rubi Thapa, Anna Timofiejczuk, Dhruba Panthi, Anil Kunwar

doi:10.1016/j.ijsolstr.2024.112894

利用dft信息多相场模拟揭示Al-Cu-Ni体系微观结构演化中的弹性化学效应

Through the multi-phase field method, this research explores microstructure evolution within the Al-Cu-Ni system comprising Al-rich FCC, Al2Cu, and Al3Ni intermetallic compounds (IMCs). Notably, the Al3Ni exhibits substantial growth due to its higher free energy magnitude, while the Al2Cu phase diminishes within the FCC matrix. Additionally, this study investigates the impact of heterogeneous elastic effects on these microstructural changes. Density functional theory calculations were employed to determine temperature-dependent elastic tensor at a simulation temperature of 723 K. Initially both cases, simulations with elastic constants at 0 K and 723 K, start with identical grain areas. But by 21.45 ms, deviations notably intensify to 18.18% for single grains, underlining the importance of temperature-calibrated elastic tensor in the phase evolution driven by elastochemical effects.

通过多相场方法，本研究探索了由富铝 FCC、Al2Cu 和 Al3Ni 金属间化合物 (IMC) 组成的 Al-Cu-Ni 体系中的微观结构演变。值得注意的是，Al3Ni 因其自由能较高而呈现出大幅增长，而 Al2Cu 相则在 FCC 基体中逐渐减少。此外，本研究还探讨了异质弹性效应对这些微观结构变化的影响。密度泛函理论计算用于确定模拟温度为 723 K 时随温度变化的弹性张量。在两种情况下，模拟温度分别为 0 K 和 723 K 时的弹性常数，开始时晶粒面积相同。但到 21.45 毫秒时，单个晶粒的偏差明显增大到 18.18%，这突出了温度校准弹性张量在弹性化学效应驱动的相演变中的重要性。

Journal of the Mechanics and Physics of Solids

Impact of out-of-plane deformation on atomic reconstruction in twisted van der Waals bilayers

Baidu Zhang, Wei Qiu, Xiangbiao Liao, Linghui He, Yong Ni

doi:10.1016/j.jmps.2024.105693

面外变形对扭曲范德华双层中原子重构的影响

The effects of out-of-plane deformation on atomic relaxation in twisted van der Waals bilayers are investigated by comprehensive multiscale modeling and simulations. The model integrates the DFT-informed generalized stacking-fault energy for interlayer interaction between layers and the Föppl–von Kármán plate theory for elastic energy in each layer with minimization of the total free energy for atomic relaxation governed by a gradient flow method. Our simulation results elucidate twist-angle dependent moiré pattern, strain field, tortional displacement field and stacking domain structures, in good agreement with recent experimental observations. In particular, we derive the strain soliton solution at a small twist angle and the soliton free elastic solution at a large twist angle for the reconstructed van der Waals bilayer with out-of-plane deformation. These results show that out-of-plane deformation not only modifies the strain soliton width but also induces substantial alterations in the strain field, local rotation, and stacking structures. Our findings reveal the non-neglectable role played by out-of-plane deformation in the atomic relaxation of twisted van der Waals bilayers, particularly at smaller twist angles. The intricate interplay between in-plane atomic relaxation and out-of-plane deformation provides opportunities for strain engineering in twisted van der Waals bilayers.

通过综合多尺度建模和模拟，研究了面外变形对扭曲范德华双层中原子弛豫的影响。该模型综合了考虑层间相互作用的dft广义叠加-断层能和考虑每层弹性能的Föppl-von Kármán板块理论，并采用梯度流法控制原子弛豫的总自由能最小化。我们的模拟结果阐明了与扭转角有关的波纹模式、应变场、扭转位移场和叠加畴结构，与最近的实验观察结果吻合得很好。特别地，我们导出了具有面外变形的重构范德华双层在小扭转角下的应变孤子解和大扭转角下的自由孤子弹性解。这些结果表明，面外变形不仅改变了应变孤子宽度，而且引起了应变场、局部旋转和堆积结构的实质性变化。我们的发现揭示了面外变形在扭曲范德华双层的原子弛豫中起着不可忽视的作用，特别是在较小的扭转角下。面内原子弛豫和面外变形之间复杂的相互作用为扭曲范德华双层结构的应变工程提供了机会。

Mechanics of Materials

An efficient active-stress electromechanical isogeometric shell model for muscular thin film simulations

Michele Torre, Simone Morganti, Alessandro Nitti, Marco Donato de Tullio, Josef Kiendl, Francesco Silvio Pasqualini, Alessandro Reali

doi:10.1016/j.mechmat.2024.105046

用于肌肉薄膜模拟的有效主动应力机电等几何壳模型

We propose an isogeometric approach to model the deformation of active thin films using layered, nonlinear, Kirchhoff–Love shells. Isogeometric Collocation and Galerkin formulations are employed to discretize the electrophysiological and mechanical sub-problems, respectively, with the possibility to adopt different element and time-step sizes. Numerical tests illustrate the capabilities of the active-stress-based approach to effectively simulate the contraction of thin films in both quasi-static and dynamic conditions.

我们提出了一种等几何方法来模拟活动薄膜的变形，使用分层的，非线性的，Kirchhoff-Love壳。采用等几何配置和伽辽金公式分别对电生理子问题和力学子问题进行离散化，可以采用不同的单元和时间步长。数值试验表明，基于主动应力的方法能够有效地模拟薄膜在准静态和动态条件下的收缩。

International Journal of Plasticity

Restraining geometrically-necessary dislocations to the active slip systems in a crystal plasticity-based finite element framework

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

doi:10.1016/j.ijplas.2024.104013

基于晶体塑性的有限元框架中主动滑移系统的几何必要位错抑制

Strain gradients have been cast in the form of geometrically-necessary dislocations (GND) to relate the length-scale dependence of strength and to determine potential sites for failure initiation. The literature contains various different incompatibility measures, the main ones being: the total form ( ∇ × F p ), the rate form for large displacements ( ∇ × γ ̇ a n a F p ), and the slip gradient form ( ∇ γ ̇ a ). Here these different approaches are compared rigorously for the first time. Obtaining GND densities when using the total form is a rank-deficit linear problem, solved by singular value decomposition (SVD) known as the Least Squares Minimization (L2 method). Alternative methods to find GND densities such as Karush-Kuhn–Tucker (KKT) optimization are also investigated. Both L2 and KKT method predict unrealistic GND densities on inactive slip systems leading to excessive strain hardening; even for a single crystal single slip case. Therefore, the restriction of GNDs to the active slip systems by using a threshold based on the total slip is found to be essential. This proposed restriction reveals relatively consistent results for various single crystal single slip cases including: simple shear, uniaxial tension, and four-point bending. In addition, the small numerical differences in the slip leads to large discrepancies in the flow stress due to error accumulation, even for strain-gradient-free uniaxial tension, hence a threshold for the GND density increment ( 2 × 1 0 2 m−2) is used in all models to avoid formation of artificial GND densities. Finally, the proposed method is applied to GND density evolution for a grain inside a polycrystal aggregate having a complex stress state. The total forms, that use the curl of the plastic deformation gradient, with the active slip system restriction giving the lowest incompatibility errors suggest them to be the most reliable GND measures.

应变梯度以几何必要位错(GND)的形式铸造，以联系强度的长度尺度依赖性，并确定潜在的破坏起始位置。文献中包含了各种不同的不相容测度，主要有:总形式(∇× F p)、大位移时的速率形式(∇× γ ^ an ^ a F p)和滑移梯度形式(∇γ ^ a)。本文首次对这些不同的方法进行了严格的比较。当使用总形式时，获得GND密度是一个秩亏线性问题，通过称为最小二乘最小化(L2方法)的奇异值分解(SVD)来解决。还研究了寻找GND密度的替代方法，如Karush-Kuhn-Tucker (KKT)优化。L2和KKT方法在非活动滑移系统上预测的GND密度都不现实，导致过度应变硬化;即使是单晶单滑移情况。因此，使用基于总滑移的阈值来限制GNDs对活动滑移系统的影响是必要的。这一建议的限制揭示了各种单晶单滑移情况的相对一致的结果，包括:简单剪切，单轴拉伸和四点弯曲。此外，即使对于无应变梯度的单轴拉伸，滑移的小数值差异也会导致由于误差积累而产生的大流动应力差异，因此在所有模型中都使用了地地密度增量的阈值(2 × 10 × 2 m−2)，以避免人工地地密度的形成。最后，将该方法应用于具有复杂应力状态的多晶聚集体中颗粒的GND密度演化。利用塑性变形梯度的旋度和主动滑移系统约束的总形式给出了最低的不相容误差，这表明它们是最可靠的GND措施。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年5月27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 2 篇，Composites Science and Technology 1 篇Composite StructuresDeployment behavior and mechanical property analysis of Kresling origami structureJi Zhang, Changguo Wangdoi:10.1016/j.compstruct.2024.118234Kresling折纸结构展开行为及力学性能分析Kresling origami, a representative variant of origami, exhibits several distinctive features such as multistable states, changeable stiffness, and compression-torsion coupling deformation. The first focus of this study involves examining the mechanical properties of origami structures, specifically, the equivalent modulus and critical buckling stress during the deployment process are evaluated. Subsequently, the collapsibility of the Kresling origami structure is explicated with regard to energy and strain. In the folding process, when the Kresling angle is 0.0135 rad, the maximum torque is 959 Nmm, and the structure will occur snap-through instability, which is the nonlinear critical buckling load of the failure. After that, the torque decreases rapidly, and then gradually increases slowly. The mechanical model is developed and subsequently evaluated in terms of its flexibility and adjustment of stiffness. The present study investigates the buckling modes and vibration properties of Kresling origami structures, as well as their combination structures. For the buckling of Kresling origami structure, the critical buckling load of Euler buckling is 0.023 N and that of local buckling is 0.67 N. In short, the critical buckling load of the column shell is greater than that of the Kresling origami structure, which is due to the small local stiffness of structure.Kresling折纸是折纸的一种代表形式，具有多稳态、可变刚度、压扭耦合变形等特点。本研究的第一个重点是检查折纸结构的力学性能，特别是在展开过程中评估等效模量和临界屈曲应力。随后，从能量和应变两个方面阐述了Kresling折纸结构的溃散性。在折叠过程中，当Kresling角为0.0135 rad时，最大扭矩为959 Nmm，结构将发生卡断失稳，这是破坏的非线性临界屈曲载荷。之后，转矩迅速减小，然后逐渐缓慢增大。开发了机械模型，并随后根据其灵活性和刚度调整进行了评估。本文研究了Kresling折纸结构及其组合结构的屈曲模态和振动特性。对于Kresling折纸结构的屈曲，欧拉屈曲的临界屈曲载荷为0.023 N，局部屈曲的临界屈曲载荷为0.67 N。简而言之，柱壳的临界屈曲载荷大于Kresling折纸结构，这是由于结构的局部刚度较小。Composites Part A: Applied Science and ManufacturingOn how pseudo-ductility modifies the translaminar fracture toughness of composites and the nominal strength of centre-cracked specimensA. Subramani, P. Maimí, J. Costadoi:10.1016/j.compositesa.2024.108275 伪塑性如何改变复合材料的跨层断裂韧性和中心裂纹试件的名义强度Among the efforts to revert the traditionally brittle characteristic of laminated composites, pseudo-ductility relies on utilising hybridisation to stimulate sub-critical damage mechanisms. However, how such pseudo-ductility would translate into an increase in material toughness or an improvement in the strength of the sub-components remains unclear. To elucidate this, we perform a numerical study departing from a parameterised pseudo-ductile model implemented in a finite element model. We use non-dimensional analysis to investigate the effect of the two most relevant parameters: pseudo-ductile strain ( ɛ d ) and the ratio of ultimate strength to pseudo-ductile yield strength ( σ f / σ y ). We infer material toughness from the simulation of Compact Tension specimens, and it is shown to increase linearly with ɛ d , and non-linearly with σ f / σ y but tends to a plateau. Then, the simulation of Centre Cracked scaled specimens reveal that the nominal strength increases on the elastic limit extreme (large specimens) but decreases below a given size.在恢复层合复合材料传统脆性特性的努力中，伪延性依赖于利用杂化来刺激亚临界损伤机制。然而，这种伪延展性如何转化为材料韧性的增加或子部件强度的改善仍不清楚。为了阐明这一点，我们从一个参数化的伪延性模型出发，在一个有限元模型中实现了一个数值研究。我们使用无量纲分析来研究两个最相关参数的影响:伪延性应变(d)和极限强度与伪延性屈服强度之比(σ f / σ y)。材料的韧性随d的变化呈线性增加，随σ f / σ y的变化呈非线性增加，但趋于平稳。然后，对中心裂纹试件进行了数值模拟，结果表明，在弹性极限极限(大试件)上，公称强度增大，但在给定尺寸下，公称强度减小。All-composite honeycomb-enhanced corrugated hybrid structures to improve flexural responsesCuiping Bai, Hougai Shi, Qu Yan, Haiying Cao, Wenyi Bao, Xiaofei Li, Hualin Fandoi:10.1016/j.compositesa.2024.108282改进弯曲响应的全复合蜂窝增强波纹混合结构An all-composite corrugated hybrid structure was proposed. The Nomex honeycomb was filled to enhance carbon fiber reinforced polymer (CFRP) corrugated sandwich against mono-corrugation flexural collapse. Three-point bending behaviors of the honeycomb enhanced corrugated sandwich (HECS), taking account of the effects of honeycomb density, loading position, and honeycomb proportion, were investigated. The bearing capacity of the HECS is greatly increased. The mutual constraint between the web and honeycomb exhibits different damage modes from those of corrugated and honeycomb sandwich. The peak load and elastic stiffness of the HECS are 1.37 times and 1.4 times higher than that of unenhanced corrugated sandwich, respectively. Numerical and analytical models were able to consistently predict the deflection and stiffness of the HECS.提出了一种全复合波纹杂化结构。Nomex蜂窝填充增强碳纤维增强聚合物(CFRP)波纹夹层抗单波纹弯曲崩溃。研究了蜂窝增强波纹夹层结构在考虑蜂窝密度、加载位置和蜂窝比例影响下的三点弯曲行为。该结构的承载能力大大提高。腹板与蜂窝之间的相互约束表现出不同于波纹夹层和蜂窝夹层的损伤模式。其峰值荷载和弹性刚度分别是未增强波纹夹层的1.37倍和1.4倍。数值和解析模型能够一致地预测HECS的挠度和刚度。Composites Science and TechnologyCharacterization and prediction of frequency- and moisture-dependent damping behaviors for hierarchical flax fiber reinforced composite laminatesSongli Tan, Zhen Zhang, Qian Li, Weidong Yang, Tao Yu, Yan Lidoi:10.1016/j.compscitech.2024.110682 层次化亚麻纤维增强复合材料层合板频率和湿度相关阻尼特性的表征和预测This study aims to investigate the damping behaviors of unidirectional and laminated flax fiber reinforced composites (FFRCs) under various frequencies and moisture absorption conditions. The damping performances of unidirectional (0°, 45°, 90°), orthotropic and symmetric angle-ply composites were evaluated by the cantilever percussion free-decay method to establish the relationship between frequency, hygroscopicity and damping ratio. To elucidate the frequency- and moisture-dependent damping mechanisms, the glass-transition temperature and modal analysis were examined using dynamic mechanical analysis and a 3D scanning laser Doppler vibrometer respectively. To predict the frequency- and moisture-dependent damping behaviors for hierarchical FFRC laminates, a finite element model subject to the damping test was developed by integrating laminate theory and the complex eigenvalue method in a user-defined material subroutine. The findings indicate that moisture absorption leads to an increase in the damping ratio and changes the frequency-dependent trend. The distinct hierarchical structures of flax yarns result in strong frequency- and moisture-dependent damping performances in FFRC laminates. A significant agreement between the experimental modal frequency, damping ratio, mode of vibration of all composites and those values derived from the established modelling was achieved. It offers a foundational parameter for precisely predicting the damping properties of FFRC laminates with complex stacking sequences and designing safe and reliable FFRC structures integrating load-bearing and damping functionalities.研究了不同频率和吸湿条件下单向和层压亚麻纤维增强复合材料(ffrc)的阻尼特性。采用悬臂冲击自由衰减法对单向(0°、45°、90°)、正交各向异性和对称角层复合材料的阻尼性能进行了评价，建立了频率、吸湿性和阻尼比之间的关系。为了阐明频率和湿度相关的阻尼机制，分别使用动态力学分析和三维扫描激光多普勒振动仪对玻璃化转变温度和模态进行了分析。为了预测层次化FFRC层合板的频率和湿度相关阻尼行为，在自定义材料子程序中，将层合板理论与复特征值法相结合，建立了一个阻尼试验的有限元模型。结果表明，吸湿导致阻尼比增大，并改变了频率依赖趋势。亚麻纱独特的层次结构使得FFRC层压板具有较强的频率依赖性和湿度依赖性阻尼性能。所有复合材料的实验模态频率、阻尼比、振动模态与建立的模型得出的值之间具有显著的一致性。为精确预测复杂叠置顺序的FFRC层合板的阻尼特性，设计安全可靠的集承载和阻尼功能于一体的FFRC结构提供了基础参数。来源：复合材料力学仿真Composites FEM