【新文速递】2024年6月27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，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 3 篇

International Journal of Solids and Structures

Indentation of circular hyperelastic membrane with hole by cylindrical indenter

Alexey M. Kolesnikov

doi:10.1016/j.ijsolstr.2024.112944

圆柱形压头对带孔的圆形超弹性膜的压痕作用

We consider the problem of indentation of a thin circular elastic plate with a hole in the centre by a cylindrical indenter under large strains. We use the nonlinear theory of isotropic incompressible hyperelastic membranes and consider a quasi-static process of indentation. We use Coulomb’s law to describe the friction at a contact. The goals of this study are to determine and to compare the effects of friction, material parameters and pre-stretch of the membrane on the indentation process.

我们考虑了中心有孔的圆形弹性薄板在大应变下被圆柱形压头压入的问题。我们使用各向同性不可压缩超弹性膜的非线性理论，并考虑压痕的准静态过程。我们使用库仑定律来描述接触处的摩擦。本研究的目标是确定和比较摩擦、材料参数和膜的预拉伸对压痕过程的影响。

Journal of the Mechanics and Physics of Solids

Nonuniqueness in defining the polarization: Nonlocal surface charges and the electrostatic, energetic, and transport perspectives

Shoham Sen, Yang Wang, Timothy Breitzman, Kaushik Dayal

doi:10.1016/j.jmps.2024.105743

定义极化的非唯一性：非局部表面电荷以及静电、能量和传输视角

Ionic crystals, ranging from dielectrics to solid electrolytes to complex oxides, play a central role in the development of modern technologies for energy storage, sensing, actuation, and other functional applications. Mesoscale descriptions of these crystals are based on the continuum polarization density field to represent the effective physics of charge distribution at the scale of the atomic lattice. However, a long-standing difficulty is that the classical electrostatic definition of the macroscopic polarization — as the dipole or first moment of the charge density in a unit cell — is not unique; rather, it is sensitive to translations of the unit cell in an infinite periodic system. This unphysical non-uniqueness has been shown to arise from starting directly with an infinite system — wherein the boundaries are ill-defined — rather than starting with a finite body and taking appropriate limits. This limit process shows that the electrostatic description requires not only the bulk polarization density, but also the surface charge density, as the effective macroscopic descriptors; that is, a nonlocal effective description. Other approaches to resolve this difficulty include the popular modern theory of polarization that completely sets aside the polarization as a fundamental quantity in favor of the change in polarization from an arbitrary reference value and then relates the change in polarization to the transport of charge (the “transport” definition); or, in the spirit of classical continuum mechanics, to define the polarization as the energy-conjugate to the electric field (the “energetic” definition). This work examines the relation between the classical electrostatic definition of polarization, and the transport and energy-conjugate definitions of polarization. We show the following: (1) The transport of charge does not correspond to the change in polarization in general; instead, one requires additional simplifying assumptions on the electrostatic definition of polarization for these approaches to give rise to the same macroscopic electric fields. Thus, the electrostatic definition encompasses the transport definition as a special case. (2) The energy-conjugate definition has both bulk and surface contributions; while traditional approaches neglect the surface contribution, we find that accounting for the nonlocal surface contributions is essential to be consistent with the classical definition and obtain the correct macroscopic electric fields.

从电介质、固体电解质到复杂氧化物，离子晶体在现代能量存储、传感、致动和其他功能应用技术的发展中发挥着核心作用。这些晶体的中尺度描述基于连续极化密度场，以表示原子晶格尺度上电荷分布的有效物理学。然而，一个长期存在的难题是，宏观极化的经典静电定义--作为单元格中电荷密度的偶极子或第一矩--并不是唯一的；相反，它对无限周期系统中单元格的平移很敏感。这种非物理的非唯一性已被证明是由于直接从无限系统开始（该系统的边界定义不清），而不是从有限体开始并进行适当的极限处理而产生的。这一极限过程表明，静电描述不仅需要体极化密度，还需要表面电荷密度作为有效的宏观描述符；也就是说，需要一种非局部的有效描述。解决这一难题的其他方法包括流行的现代极化理论，该理论将极化作为基本量完全搁置，而将极化与任意参考值的变化联系起来，然后将极化的变化与电荷的传输联系起来（"传输 "定义）；或者根据经典连续介质力学的精神，将极化定义为电场的能量共轭（"能量 "定义）。这项研究探讨了极化的经典静电定义与极化的输运定义和能量共轭定义之间的关系。我们证明了以下几点：(1) 一般来说，电荷的传输与极化的变化并不对应；相反，需要对极化的静电定义进行额外的简化假设，这些方法才能产生相同的宏观电场。因此，静电定义包含了作为特例的传输定义。(2) 能量共轭定义既有体层贡献，也有表面贡献；虽然传统方法忽略了表面贡献，但我们发现，为了与经典定义保持一致并获得正确的宏观电场，必须考虑非局部表面贡献。

Mechanics of Materials

Effect of stacking fault energy on hetero-deformation in gradient nanograined Cu-Ni alloys

Like Xu, Zhifeng Huang, Qiang Shen, Fei Chen

doi:10.1016/j.mechmat.2024.105074

堆积断层能对梯度纳米粒状铜镍合金异质变形的影响

The stacking fault energy (SFE) effect on nanocrystalline metal deformation mechanisms has been extensively studied from dislocation and grain boundary perspectives. Compared to homogeneous nanocrystalline structures, the gradient nanograined (GNG) structure exhibits varied grain sizes, resulting in different SFE effects across regions during the hetero-deformation process. In this work, molecular dynamics (MD) simulation is conducted on GNG Cu-Ni binary alloys with incremental Ni concentration, to investigate the SFE effect at different deformation stages of the GNG structure. It is revealed that the elastic deformation stage shows a close relationship with alloy intrinsic property (e.g. elastic modulus) from Ni concentration variation, with neglectable SFE effect. Under the hetero-deformation stage, different from the homogeneous polycrystalline counterpart, the effect under high SFE condition is demonstrated from the overall dislocation density decline and the competition between the perfect and partial dislocations in the gradually varied grains across the GNG structure, which finally results in lower strain gradient, geometry necessary dislocation density, and a less effective hetero-deformation process. The active GB sliding and migration are found to offset this dislocation density decline in the sample with the relatively high SFE, which brings in higher GB stress concentration and larger GB free volume of the GNG structure. Besides, the GB relaxation across the GNG structure under the high strain rate tensile loading is also illustrated and discussed. The results further support the essential deformation mechanism underlying heterostructure materials.

人们从位错和晶界的角度对堆积断层能（SFE）对纳米晶金属变形机制的影响进行了广泛的研究。与均质纳米晶结构相比，梯度纳米晶（GNG）结构的晶粒大小各不相同，因此在异质形变过程中各区域的 SFE 效应也不尽相同。本研究对镍浓度递增的 GNG 铜镍二元合金进行了分子动力学（MD）模拟，以研究 GNG 结构在不同变形阶段的 SFE 效应。结果表明，弹性变形阶段的镍浓度变化与合金固有特性（如弹性模量）关系密切，而 SFE 效应可忽略不计。在异质变形阶段，与同质多晶不同的是，高 SFE 条件下的效应表现为整体 位错密度下降，以及整个 GNG 结构中逐渐变化的晶粒中完全位错和部分位错之间的竞争，最终导致较低的应变梯度和必要的几何位错密度，以及较不有效的异质变形过程。在 SFE 相对较高的样品中，活跃的 GB 滑动和迁移抵消了位错密度的下降，从而带来了更高的 GB 应力集中和更大的 GB 自由体积。此外，还说明并讨论了在高应变速率拉伸加载下 GNG 结构的 GB 松弛情况。这些结果进一步支持了异质结构材料的基本变形机制。

International Journal of Plasticity

Unveiling the deformation micro-mechanism for mechanical anisotropy of a CoCrFeNi medium entropy alloy

Qiang Zhang, Shaoshi Rui, Xianfeng Ma, Ligang Song, Fei Zhu, Yaowu Pei, Jiaxin Wu

doi:10.1016/j.ijplas.2024.104051

揭示钴铬镍铁合金机械各向异性的变形微观机制

The equiatomic Cr-Co-Fe-Ni medium-entropy alloy has the face-centered cubic structure. Single crystals of this alloy were tested by in-situ micropillar compression along different loading axes under scanning electron microscope. The transmission electron microscopy characterization and molecular dynamics simulation were incorporated for quantitative analysis of the effects of different crystal orientations on the deformation mechanisms. The <001>-oriented pillar not only exhibited extensive deformation-induced nano twinning, but also has been identified for the first time to undergo the FCC-HCP phase transformation at room temperature. The strain localization tendency of <011>-oriented samples was confirmed through uniaxial tests to interpret the significant serration on stress-strain curves. The prominent strain hardening of <111>-oriented pillars was attributed to intense intersection between slip planes as evidenced by the extra density of Lomer-Cottrell locks. Such a high hardening rate has caused subsequent kinking of pillars. Functional division of different regions of kink band is conducted based on Orowan model. In principle, multi-principal element alloys can theoretically be designed and developed to combine a variety of excellent properties, which is an important class of candidate structural materials for advanced engineering systems. These findings provide promising guidance for understanding the mechanical anisotropy and application of these alloys.

等原子铬-氯-铁-镍中熵合金具有面心立方结构。在扫描电子显微镜下，对该合金的单晶体进行了沿不同加载轴的原位微柱压缩测试。结合透射电子显微镜表征和分子动力学模拟，定量分析了不同晶体取向对变形机制的影响。以 <001> 为取向的晶柱不仅表现出广泛的形变诱导纳米孪晶，还首次发现其在室温下发生了 FCC-HCP 相变。通过单轴测试证实了<011>取向样品的应变局部化趋势，从而解释了应力-应变曲线上的显著锯齿状。<111>取向柱的突出应变硬化归因于滑移面之间的强烈交错，这一点可以从额外密度的 Lomer-Cottrell 锁得到证明。如此高的硬化率导致了随后的石柱扭结。根据奥罗万模型对扭结带的不同区域进行了功能划分。从原理上讲，理论上可以设计和开发出兼具多种优异性能的多主元合金，这是先进工程系统中一类重要的候选结构材料。这些发现为理解这些合金的力学各向异性和应用提供了很好的指导。

Thin-Walled Structures

Explicit design optimization of air rudders for maximizing stiffness and fundamental frequency

Yibo Jia, Wen Meng, Zongliang Du, Chang Liu, Shanwei Li, Conglei Wang, Zhifu Ge, Ruiyi Su, Xu Guo

doi:10.1016/j.tws.2024.112152

优化空气舵的显式设计，最大限度地提高刚度和基频

In aerospace engineering, there is a growing demand for lightweight design through topology optimization. This paper presents a novel design optimization method for stiffened air rudders, commonly used for aircraft attitude control, based on the Moving Morphable Component (MMC) method. The stiffeners within the irregular enclosed design domain are modeled as MMCs and discretized by shell elements, accurately capturing their geometry and evolution during optimization process using explicit parameters. In order to maximize the stiffness and fundamental frequency of the rudder structures, numerical analysis algorithms were developed with shape sensitivity analysis conducted. To comply with the manufacturing requirement, a minimum thickness is prescribed for the stiffeners, and the thickness and density penalty schemes are proposed to meet the minimum thickness constraint and prevent the occurrence of spurious modes respectively. The method’s effectiveness was demonstrated through optimization examples of a typical trapezoidal air rudder, illustrating the significance of stiffener’s distribution on design objectives. The explicit modeling characteristics allow for directly importing the optimization results into CAD systems, significantly enhancing the engineering applicability.

在航空航天工程领域，通过拓扑优化实现轻量化设计的需求日益增长。本文针对飞机姿态控制中常用的加劲空气方向舵，提出了一种基于移动可变形组件（MMC）方法的新型设计优化方法。不规则封闭设计域内的加强筋被建模为 MMC，并通过壳元素进行离散化，在优化过程中使用显式参数准确捕捉其几何形状和演变过程。为了最大限度地提高尾舵结构的刚度和基频，开发了数值分析算法，并进行了形状敏感性分析。为符合制造要求，对加强筋规定了最小厚度，并提出了厚度和密度惩罚方案，以分别满足最小厚度约束和防止出现杂散模态。该方法的有效性通过典型梯形空气舵的优化实例得到了证明，说明了加劲件分布对设计目标的重要性。显式建模特性允许将优化结果直接导入 CAD 系统，大大提高了工程应用性。

Forced vibration analysis of a beam-plate system coupled through multiple nonlinear single-freedom-degree systems

Mingfei Chen, Rongshen Guo, Fanhao Guo, Yuhao Zhao

doi:10.1016/j.tws.2024.112153

通过多个非线性单自由度系统耦合的梁-板系统的受迫振动分析

A beam-plate coupling system is widely used in the construction of different frameworks across industries according to engineering application requirements. In this paper, a nonlinear single-degree-of-freedom structure is introduced as a coupling element between the beam and the plate. Therefore, a coupling system connected through a plurality of the nonlinear single-degree-of-freedom structures is proposed with exposure of its operational mechanism and the dynamic behavior analysis as required. The nonlinear coupled governing equations of the beam-plate system with series nonlinear energy sinks are established according to the Hamilton principle and solvable by the Galerkin truncation method. Meanwhile, the nonlinear characteristics of transverse vibration of the coupling system are studied for discussing the effect of nonlinear stiffness on a low-frequency response of the beam-plate system. Further, the transverse vibration of the system may vary with changes in the nonlinear stiffness, the external viscous damping, and the motion mass of the nonlinear single-degree-of-freedom structures. Accordingly, the variations along with these factors are investigated. The results indicate that a reasonable nonlinear single-degree-of-freedom structure can have a significant influence on the transverse vibration characteristics of the beam-plate system.

根据工程应用要求，梁板耦合系统被广泛应用于各行各业的不同框架结构中。本文引入非线性单自由度结构作为梁和板之间的耦合元件。因此，本文提出了一个通过多个非线性单自由度结构连接起来的耦合系统，并根据需要对其运行机制和动态行为进行了分析。根据汉密尔顿原理，建立了具有串联非线性能量汇的梁-板系统的非线性耦合控制方程，并可通过伽勒金截断法求解。同时，研究了耦合系统横向振动的非线性特性，以讨论非线性刚度对梁板系统低频响应的影响。此外，系统的横向振动可能会随着非线性刚度、外部粘性阻尼和非线性单自由度结构的运动质量的变化而变化。因此，我们对这些因素的变化进行了研究。结果表明，合理的非线性单自由度结构会对梁-板系统的横向振动特性产生重大影响。

Pin-ended stainless steel equal-leg angle section members under compression and major-axis bending: Experimentation, FE modelling and design

Behnam Behzadi-Sofiani, M. Ahmer Wadee, Leroy Gardner

doi:10.1016/j.tws.2024.112154

压缩和主轴弯曲下的销端不锈钢等脚角钢截面构件：实验、FE 建模和设计

The behaviour and design of cylindrically-pinned stainless steel equal-leg angle section members under compression and compression combined with strong-axis bending are investigated herein. An experimental investigation, including material testing, initial geometric imperfection measurements and physical tests on hot-rolled stainless steel equal-leg angle section members is first presented. Numerical models are developed by means of shell finite element modelling formulated within ABAQUS and validated against experimental data. A numerical parametric study is then presented considering both hot-rolled and cold-formed stainless steel equal-leg angle section columns alongside beam–columns with a wide range of cross-section and member geometries. Finally, new design proposals for cylindrically-pinned stainless steel equal-leg angle section members under compression and compression plus major-axis bending are developed and verified against the results of physical experiments and numerical simulations. The proposed design rules are shown to offer substantially more accurate and consistent resistance predictions compared to existing codified design rules. The reliability of the new design provisions, with a recommended partial safety factor γ M1 = 1 . 1 , is verified following the EN 1990 procedure.

本文研究了圆柱销钉不锈钢等脚角截面构件在压缩和压缩结合强轴弯曲情况下的行为和设计。首先介绍了一项实验研究，包括材料测试、初始几何缺陷测量和热轧不锈钢等脚角钢截面构件的物理测试。通过在 ABAQUS 中建立的壳体有限元模型开发了数值模型，并根据实验数据进行了验证。然后，考虑到热轧和冷弯不锈钢等脚角钢截面柱以及具有各种截面和构件几何形状的梁柱，进行了数值参数研究。最后，针对受压和受压加主轴弯曲的圆柱销不锈钢等截面角钢构件提出了新的设计建议，并根据物理实验和数值模拟结果进行了验证。结果表明，与现有的成文设计规则相比，所提出的设计规则能提供更准确、更一致的阻力预测。新设计规定的可靠性（建议的局部安全系数 γ M1 = 1 .1 的可靠性按照 EN 1990 程序进行了验证。