【新文速递】2024年2月12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 2 篇，International Journal of Plasticity 2 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Crystal plasticity model for describing the work hardening of A5052-O sheets subjected to various loading paths

Kengo Yoshida

doi:10.1016/j.ijsolstr.2024.112697

用于描述不同加载路径下 A5052-O 板材加工硬化的晶体塑性模型

The Bauschinger effect, which refers to softening after strain reversal, significantly affects the springback simulation of stamped sheet metals. Therefore, a constitutive model that can describe this effect is required to perform accurate springback simulations. This study developed a crystal plasticity model that accurately reproduces the Bauschinger and cross effects of aluminum alloy sheets. The model is based on saturation-type equations representing the evolution of slip resistances. In addition to incorporating the work hardening of slip resistance, softening after strain reversal is incorporated. Furthermore, in the model, latent hardening increases when the slip system is inactive, whereas its evolution is suppressed when the system is activated. This formulation facilitates the reproduction of the enhanced re-yield stress followed by a reduced work-hardening rate for orthogonal loading. The simulated stress–strain curves are compared with the experimental results for an A5052-O sheet. It is shown that the proposed model accurately reproduces the reverse and orthogonal loading behaviors of the A5052-O sheet. Furthermore, the influence of the formulation of slip resistance on the predicted R value in the uniaxial tension is examined.

Bauschinger 效应是指应变反转后的软化，它对冲压薄板金属的回弹模拟有很大影响。因此，要进行精确的回弹模拟，需要一个能描述这种效应的构成模型。本研究开发了一种晶体塑性模型，可精确再现铝合金板材的鲍辛格效应和交叉效应。该模型基于表示滑移阻力演变的饱和型方程。除了包含滑移阻力的加工硬化外，还包含应变反转后的软化。此外，在该模型中，当滑移系统处于非活动状态时，潜伏硬化会增加，而当系统被激活时，其演变会被抑制。这种计算方法有助于再现正交加载时增强的再屈服应力和降低的加工硬化率。模拟的应力-应变曲线与 A5052-O 板材的实验结果进行了比较。结果表明，所提出的模型准确地再现了 A5052-O 板材的反向和正交加载行为。此外，还研究了单轴拉伸时滑移阻力配方对预测 R 值的影响。

Journal of the Mechanics and Physics of Solids

A multiscale viscoelastic fiber dispersion model for strain rate-dependent behavior of planar fibrous tissues

Kewei Li, Gerhard A. Holzapfel

doi:10.1016/j.jmps.2024.105572

平面纤维组织应变率相关行为的多尺度粘弹性纤维分散模型

Recently, we introduced an efficient discrete fiber dispersion model for characterizing the mechanical behavior of soft fibrous tissues, and we also extended that model to consider microscale collagen fiber recruitment, softening and damage. However, the viscous behavior of collagen fibers were not considered in that study. The goal of this study is to further extend the discrete fiber dispersion model to consider both elastic and viscous behavior of collagen fibers and ground substance such that the strain rate-dependent behavior of soft fibrous tissues can be characterized. We first reformulated the 3D discrete fiber dispersion model to a 2D version for tissues with planar fiber dispersion. Then, we introduced viscous parts to the model by adding Maxwell elements to the elastic parts of the strain–energy function. We implemented the proposed model in a finite element program and illustrated it with three numerical examples. The computational solutions of the first two examples agree well with our previous published results. In the last example, we characterized the rate-dependent behavior of aortic valve tissue with the proposed model. In conclusion, the proposed model is capable of characterizing the viscoelastic behavior of collagen fibers and ground substance. Future studies with patient-specific boundary conditions are necessary to verify this method.

最近，我们引入了一种高效的离散纤维分散模型来描述软纤维组织的机械行为，并将该模型扩展到考虑微尺度胶原纤维的招募、软化和损伤。然而，该研究并未考虑胶原纤维的粘性行为。本研究的目标是进一步扩展离散纤维分散模型，以考虑胶原纤维和磨碎物质的弹性和粘性行为，从而描述软纤维组织随应变速率变化的行为。我们首先将三维离散纤维弥散模型重新制定为平面纤维弥散组织的二维版本。然后，我们在应变能函数的弹性部分添加了麦克斯韦元素，从而为模型引入了粘性部分。我们在有限元程序中实现了提议的模型，并用三个数值示例进行了说明。前两个例子的计算结果与我们之前公布的结果非常吻合。在最后一个例子中，我们用所提出的模型描述了主动脉瓣组织随速率变化的行为。总之，所提出的模型能够描述胶原纤维和基底物质的粘弹性行为。未来有必要使用患者特定的边界条件进行研究，以验证这种方法。

Viscoelastic mechanics of two-dimensional granular lattices

Srinivas Selvaraju, Shailendra P. Joshi, Nikhil Karanjgaokar

doi:10.1016/j.jmps.2024.105574

二维颗粒晶格的粘弹力学

We study the rate-dependent mechanics of viscoelastic granular packings. Using a two-dimensional, square lattice of particles as a motif mimicking nominally mono-disperse granular packings, we perform a suite of finite element simulations under rate-dependent uniaxial compaction followed by unloading. The focus is on understanding the macroscopic force–displacement relations and the porosity evolution as a function of the viscoelastic relaxation parameters. For the constituent parameters considered here, the force–displacement relations show a two-stage power-law behavior, which is associated with the relative contributions of viscous dissipation and elastic effects at a particular loading rate. For a given loading rate, the nonlinearity of the porosity evolution depends on the constituent parameters and is found to be captured well by a simple analytical model. The heterogeneity of stresses during the compaction and recovery phases provide insights into the emergent complex micromechanics in simple granular motifs. Upon unloading, particles may experience transient tensile pressures, which could have implications on their failure.

我们研究了粘弹性颗粒填料随速率变化的力学特性。我们使用二维方形颗粒晶格作为模拟名义上单分散粒状填料的图案，在随速率变化的单轴压实和卸载条件下进行了一系列有限元模拟。重点是理解宏观力-位移关系以及粘弹性松弛参数作用下的孔隙率演变。对于本文所考虑的组成参数，力-位移关系显示出两阶段幂律行为，这与特定加载速率下粘滞耗散和弹性效应的相对贡献有关。在给定的加载速率下，孔隙率演变的非线性取决于组成参数，简单的分析模型可以很好地捕捉到这种非线性。压实和恢复阶段的应力异质性为简单颗粒图案中出现的复杂微观力学提供了启示。在卸载时，颗粒可能会经历瞬时拉伸压力，这可能会对其失效产生影响。

International Journal of Plasticity

Hydride-enhanced strain localization in zirconium alloy: a study by crystal plasticity finite element method

X.D. Zan, X. Guo, G.J. Weng

doi:10.1016/j.ijplas.2024.103911

锆合金中的氢化物强化应变定位：晶体塑性有限元法研究

Hydride precipitation in zirconium (Zr) alloys leads to the deterioration of mechanical properties in key components of nuclear reactors. However, the underlying mechanisms governing the failure initiation of hydrogenated Zr alloys remain incompletely understood. This study focuses on investigating the effects of δ-phase hydride precipitation on the local deformation behavior of Zr alloys. A crystal plasticity finite element method is used to simulate micropillar compression tests of single-crystal samples and macroscale tensile tests of polycrystalline samples. Our results reveal that in the case of micropillar B containing δ-hydride (where the hydride is oriented at 45° from the loading direction), the shear along the hydride–matrix interface and the misfit strain induced by hydride precipitation synergistically contribute to strain localization of Zr alloys. However, for micropillar P containing δ-hydride (where the hydride is parallel to the loading direction), the introduction of hydrides does not enhance the strain localization. Instead, it impedes the local prismatic slip. On the other hand, examination of polycrystalline samples through simulations indicates that hydrides enhance the strain localization of Zr alloys. This effect arises from several mechanisms: shear stress along hybrid–matrix interface, promoting plastic slip in the direction close to this interface; hydride-induced hindrance to certain slip bands, leading to non-uniform local deformation; and misfit strains induced by hydride precipitation, contributing to localized deformation around the hydrides.

锆（Zr）合金中的氢化物析出会导致核反应堆关键部件的机械性能下降。然而，人们对氢化锆合金引发失效的基本机制仍不甚了解。本研究的重点是研究δ相氢化物析出对 Zr 合金局部变形行为的影响。采用晶体塑性有限元法模拟单晶样品的微柱压缩试验和多晶样品的宏观拉伸试验。我们的研究结果表明，对于含有δ-氢化物的微晶柱 B（氢化物的方向与加载方向成 45°），沿氢化物-基体界面的剪切力和氢化物析出引起的错配应变协同促进了锆合金的应变定位。然而，对于含有δ-氢化物（氢化物与加载方向平行）的微柱 P，氢化物的引入并不会增强应变定位。相反，它阻碍了局部棱柱滑移。另一方面，通过模拟对多晶样品的研究表明，氢化物增强了锆合金的应变局部化。这种效应产生于以下几种机制：沿混合基体-基体界面的剪应力，促进了靠近该界面方向的塑性滑移；氢化物引起的对某些滑移带的阻碍，导致了不均匀的局部变形；氢化物析出引起的错配应变，导致了氢化物周围的局部变形。

Modeling of creep in nickel-based superalloy based on microtwinning mechanism

Jingyu Zhang, Ying Liu, Yangyang Cheng, Hao Wang, Aixue Sha, Huiling Duan

doi:10.1016/j.ijplas.2024.103916

基于微捻机制的镍基超合金蠕变建模

Microtwinning is the dominant creep deformation mechanism of nickel-based superalloy in certain temperature and stress conditions. This study proposes a novel temperature-dependent creep constitutive model based on microtwinning mechanism, which includes the glide of 1/6<112> partial dislocations and atomic diffusion in γ′ precipitates. Both microtwinning and anti-phase boundary shearing mechanisms are considered in the crystal plasticity finite element model. The numerical steady-state creep rates of single crystal and polycrystalline nickel-based superalloys agree with the experimental data at different holding stresses and temperatures. Microtwinning is activated at a lower stress than that of anti-phase boundary shearing. The competition between dislocation slip and atomic diffusion is analyzed, and the dominant mechanism is revealed for the microtwinning dominated creep at different holding stresses and temperatures. This study deepens the understanding of microtwinning-based creep deformation and could provide an effective model for the creep of nickel-based superalloy.

微孪晶是镍基超合金在特定温度和应力条件下的主要蠕变变形机制。本研究基于微孪晶机制提出了一种新的随温度变化的蠕变构成模型，其中包括 1/6<112> 部分位错的滑移和 γ′ 沉淀中的原子扩散。晶体塑性有限元模型考虑了微孪晶和反相界剪切机制。在不同的保持应力和温度下，单晶和多晶镍基超合金的数值稳态蠕变速率与实验数据一致。在比反相界剪切应力更低的应力下，微缠结被激活。分析了位错滑移和原子扩散之间的竞争，揭示了不同保持应力和温度下微扭转主导蠕变的主要机制。这项研究加深了人们对基于微孪晶的蠕变变形的理解，可为镍基超合金的蠕变提供一个有效的模型。

Thin-Walled Structures

A slice model for thermoelastic analysis of porous functionally graded material sandwich beams with temperature-dependent material properties

Zhong Zhang, Ying Sun, Xiaojian Cao, Jiajing Xu, Lu Yao

doi:10.1016/j.tws.2024.111700

多孔功能梯度材料夹层梁热弹性分析切片模型（材料特性随温度变化

Porosity usually occurs in functionally graded materials (FGMs) during the fabrication process. Its effects on the thermomechanical behaviors of FGM structures are worth studying. In this work, heat transfer and thermoelastic behaviors of porous FGM sandwich beams with temperature-dependent material properties are examined. The effective material properties are approximately estimated by the modified Voigt mixture rule. Because of the continuously varied material properties across the thickness direction, it is impractical to seek exact solutions for the beam. By proposing a slice model in which the face and core layers are divided into numerous thin slices, the material properties of each slice can be treated as uniform. Based on the model, the through-thickness temperature distribution is first obtained by using an iteration algorithm. Then the two-dimensional (2-D) thermoelasticity equations are analytically solved by using the state space method and Fourier series expansion method. The correctness of the proposed model is checked through comparison with results reported in previous works. The effects of some key factors such as the temperature dependence of material properties, volume fraction, and porosity on the thermomechanical behaviors of the beam are comprehensively studied. It is shown that with the increase of porosity, the thermal resistance capacity of the beam is enhanced yet the bending stiffness is weakened.

孔隙通常出现在功能分级材料（FGM）的制造过程中。它对 FGM 结构的热力学行为的影响值得研究。本文研究了多孔 FGM 夹层梁的传热和热弹性行为，其材料特性与温度有关。有效材料特性是通过改进的 Voigt 混合规则近似估算的。由于材料特性在厚度方向上不断变化，因此寻求梁的精确解是不切实际的。通过提出一种切片模型，将面层和芯层分成许多薄片，可以将每个薄片的材料特性视为均匀的。在该模型的基础上，首先使用迭代算法获得厚度温度分布。然后利用状态空间法和傅里叶级数展开法对二维热弹性方程进行解析求解。通过与前人研究成果的对比，检验了所提模型的正确性。全面研究了一些关键因素，如材料特性、体积分数和孔隙率的温度依赖性对梁热力学行为的影响。结果表明，随着孔隙率的增加，梁的热阻能力增强，但弯曲刚度减弱。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年1月26日固体力学SCI期刊最新文章

今日更新：Journal of the Mechanics and Physics of Solids 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 2 篇Journal of the Mechanics and Physics of SolidsEffective isometries of periodic shellsHussein Nassar, Andrew Weberdoi:10.1016/j.jmps.2024.105553周期壳层的有效等距We argue that the standard classification of isometric deformations into infinitesimal v.s. finite is inadequate for the study of compliant shell mechanisms. Indeed, many compliant shells, particularly ones that are periodically corrugated, exhibit low-energy deformations that are far too large to be infinitesimally isometric and far too rich to be finitely isometric. Here, rather than abandon the geometric standpoint in favor of a full theory of elastic shells, we introduce the concept of effective isometric deformations defined as deformations that are first-order isometric in a small scale separation parameter given by the ratio of the size of the corrugation to the size of the shell. The main result then states that effective isometries are solutions to a quasilinear second-order PDE whose type is function of an effective geometric Poisson’s ratio. The result is based on a self-adjointness property of the differential operator of infinitesimal isometries; it holds for periodic surfaces that are smooth, piecewise smooth or polyhedral, i.e., periodic surfaces with or without straight and curved creases. In particular, it unifies and generalizes a series of previous results regarding the effective Poisson’s ratio of parallelogram-based origami tessellations. Numerical simulations illustrate and validate the conclusions.我们认为，将等距变形分为无穷小与有限的标准分类对于柔性壳机构的研究是不够的。事实上，许多柔性壳，特别是周期性波纹的壳，表现出低能量变形，这种变形太大而不能无限等距，也太丰富而不能无限等距。在这里，我们不是为了支持弹性壳的完整理论而放弃几何观点，而是引入有效等距变形的概念，将其定义为由波纹尺寸与壳尺寸之比给出的小尺度分离参数中的一阶等距变形。主要结果表明，有效等距是拟线性二阶偏微分方程的解，其类型是有效几何泊松比的函数。该结果是基于无穷小等距的微分算子的自伴随性质;它适用于光滑、分段光滑或多面体的周期曲面，即具有或不具有直线和弯曲折痕的周期曲面。特别地，它统一和推广了一系列先前关于基于平行四边形的折纸镶嵌的有效泊松比的结果。数值模拟验证了本文的结论。International Journal of PlasticityLithium Concentration and Atomic Chain Bridging Induced Strength–Ductility Synergy in Amorphous Lithiated Sulfur CathodesYuan Gao, Siyi Huang, Xiaoyan Li, Yuli Chen, Bin Dingdoi:10.1016/j.ijplas.2024.103891 锂离子浓度和原子链桥接诱导的非晶锂化硫阴极的强度-延展性协同作用As an eminent candidate for next-generation cathode materials, sulfur undergoes severe volume changes during electrochemical cycling, resulting in material fractures and performance degradation. Although the electrochemical characteristics of lithiated sulfur have been rigorously studied, their mechanical properties, particularly fracture mechanisms, remain insufficiently understood. To address this gap, we conducted comprehensive atomistic simulations to investigate the fracture behavior of amorphous lithiated sulfur (a-LixS). Our findings reveal that as lithium concentration increases, the fracture mechanism transits from brittle governed by nanoscale cavitation instability to ductile dominated by plastic shear bands launched at the crack tip. This transition is contingent upon local hydrostatic stress exceeding the cavitation strength, elucidated through atomic-level bonding dynamics including rupture, reformation and rotation. At low lithium concentrations, atomic chain bridging posterior to the crack tip is simultaneously identified to enhance crack resistance. The lithiation-induced fracture toughness enhancement is further quantified via domain J-integral analysis. Notably, a unique strength–ductility synergy is identified for a-LixS, attributed to cooperation between lithiation induced heterogeneous bonding environments and atomic chain bridging. This study provides valuable atomic-scale insights into the fracture mechanisms of sulfur cathodes, thereby informing the design of high-energy and durable electrode materials for future applications.硫作为下一代阴极材料的重要候选者，在电化学循环过程中会发生剧烈的体积变化，导致材料断裂和性能下降。虽然锂化硫的电化学特性已经得到了严格的研究，但它们的力学性能，特别是断裂机制，仍然没有得到充分的了解。为了解决这一空白，我们进行了全面的原子模拟来研究非晶锂化硫(a-LixS)的断裂行为。研究结果表明，随着锂离子浓度的增加，断裂机制由纳米级空化失稳控制的脆性向裂纹尖端发起的塑性剪切带主导的延性转变。这种转变取决于超过空化强度的局部静水应力，这可以通过原子水平的键合动力学(包括破裂、重组和旋转)来解释。在低锂浓度下，裂纹尖端后方的原子链桥接同时被识别，以增强抗裂性。通过区域j积分分析进一步量化了锂化引起的断裂韧性增强。值得注意的是，a- lixs具有独特的强度-延展性协同作用，这归因于锂化诱导的非均相键环境和原子链桥接之间的合作。这项研究为硫阴极的断裂机制提供了有价值的原子尺度的见解，从而为未来应用的高能耐用电极材料的设计提供了信息。Thin-Walled StructuresA two-step strategy to graft CNTs onto titanium/CFRP interface for interfacial enhancementNaiyu Jiang, Yingze Li, Nan Zhou, Hongyan Zhang, Xiaohu Zou, Dongxing Zhangdoi:10.1016/j.tws.2024.111629 两步法将CNTs接枝到钛/CFRP界面以增强界面The primary challenge of fiber metal laminates (FMLs) is the insufficient interfacial adhesion between metal and resin, which impedes the realization of the full potential. To address this issue, a two-step strategy has been proposed: firstly, via the cerium coordination-based approach, followed by grafting carbon nanotubes onto the titanium surface. This modification enhances the interfacial behavior between titanium sheets and polyetheretherketone (PEEK), resulting in increased roughness and wettability on the titanium surface, facilitating tight contact between PEEK and titanium sheets while reducing defects at the interface. Compared to CF/PEEK-sandblasted Ti, the modified CF/PEEK-Ti composites exhibit significantly enhanced interfacial shear strength, equivalent flexural strength, and interlaminate shear strength with an increase of 205.4% (39.4 MPa), 133.3% (1434.3 MPa) and 95.2% (93.7 MPa), respectively. Additionally, the failure mode has shifted from interfacial failure to cohesive failure. The interface enhancement mechanism can be attributed to the synergistic effects of coordination bonding, mechanical interlocking, and multiple interactions. This facile two-step modification method demonstrates the potential to enhance the interfacial properties of CF/PEEK-Ti composites.金属纤维层压板(FMLs)的主要挑战是金属与树脂之间的界面附着力不足，这阻碍了其充分发挥潜力。为了解决这一问题，提出了两步策略:首先，通过基于铈配位的方法，然后将碳纳米管接枝到钛表面。这种改性增强了钛片与聚醚醚酮(PEEK)之间的界面行为，从而增加了钛表面的粗糙度和润湿性，促进了PEEK与钛片之间的紧密接触，同时减少了界面上的缺陷。与CF/ peek -喷砂Ti相比，改性后的CF/PEEK-Ti复合材料的界面抗剪强度、等效抗折强度和层间抗剪强度分别提高了205.4% (39.4 MPa)、133.3% (1434.3 MPa)和95.2% (93.7 MPa)。此外，破坏模式已经从界面破坏转变为内聚破坏。界面增强机制可归因于配位键、机械联锁和多重相互作用的协同作用。这种简单的两步改性方法显示了增强CF/PEEK-Ti复合材料界面性能的潜力。Extended GBT Formulation for Eigenvalue Buckling Analyses of Thin-Walled Members with Edge-Stiffened HolesLiping Duan, Ji Miao, Hai-Ting Li, Jincheng Zhaodoi:10.1016/j.tws.2024.111628边缘加筋孔薄壁构件屈曲特征值分析的扩展GBT公式Cold-formed steel sections with edge-stiffened holes exhibit increasing popularity in the building industry. This paper extends the generalized beam theory (GBT) to the scope of handling this kind of members so that modal decomposition of the coupled buckling modes of these members into the set of pure buckling modes can be realized, which is essential for a direct strength method (DSM)-based design. The presented GBT formulation is built upon the XGBT approach that was previously proposed by the authors [1,2,3] for handling the un-stiffened perforated steel profiles, but its novelty lies in the scheme used to connect the previous approach to the MITC4 shell FEs. Specifically, the previous GBT-based beam FEs are employed to handle the perforated member but without stiffeners, and the MITC4 shell FEs are used to model the stiffeners along the hole edges; further, the mortar method-based interface elements are employed to weakly ensure the compatibility between the shell and the GBT-based FEs no matter how mismatched their meshes are. Some illustrative examples are presented to show the potential of the proposed approach, where linear buckling analysis results for the members with circular holes obtained by the present GBT are compared with those obtained by the ANSYS shell FE analyses. The presented approach shows advantages in computational costs and interpretability of the obtained results over the shell model.冷弯型钢边加筋孔在建筑工业中越来越受欢迎。本文将广义梁理论(GBT)推广到处理这类构件的范围，实现了将这类构件的耦合屈曲模态分解为纯屈曲模态集合，这是基于直接强度法(DSM)的设计所必需的。所提出的GBT配方是建立在作者先前提出的用于处理未加筋穿孔钢型材的XGBT方法的基础上的[1,2,3]，但其新颖之处在于用于将先前方法连接到MITC4壳FEs的方案。具体而言，采用先前的基于gbt的梁有限元模型来处理穿孔构件但不含加强筋，而使用MITC4壳有限元模型来模拟沿孔边缘的加强筋;此外，采用基于迫击炮法的界面单元弱保证弹体与基于gbt法的弹体之间的兼容性，无论两者的网格匹配程度如何不匹配。通过与ANSYS壳体有限元分析结果的比较，说明了该方法的可行性。与壳模型相比，该方法在计算成本和所得结果的可解释性方面具有优势。来源：复合材料力学仿真Composites FEM