【新文速递】2024年5月30日固体力学SCI期刊最新文章
今日更新：Journal of the Mechanics and Physics of Solids 3 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 2 篇
Journal of the Mechanics and Physics of Solids
A finite geometry, inertia assisted coarsening-to-complexity transition in homogeneous frictional systems
Thibault Roch, Efim A. Brener, Jean-François Molinari, Eran Bouchbinder
doi:10.1016/j.jmps.2024.105706
有限几何，惯性辅助粗糙到复杂的过渡均质摩擦系统
The emergence of statistical complexity in frictional systems (where nonlinearity and dissipation are confined to an interface), manifested in broad distributions of various observables, is not yet understood. We study this problem in velocity-driven, homogeneous (no quenched disorder) unstable frictional systems of height H. The latter are described at the continuum scale within a realistic rate-and-state friction interfacial constitutive framework, where elasto-frictional instabilities emerge from rate-weakening friction. For large H, such frictional systems were recently shown to undergo continuous coarsening until settling into a spatially periodic traveling solution. We show that when the system’s height-to-length ratio becomes small — characteristic of various engineering and geophysical systems —, coarsening is less effective and the periodic solution is dynamically avoided. Instead, and consistently with previous reports, the system settles into a stochastic, statistically stationary state. The latter features slip bursts, whose slip rate is larger than the driving velocity, which are non-trivially distributed. The slip bursts are classified into two types: predominantly non-propagating, accompanied by small total slip and propagating, accompanied by large total slip. The statistical distributions emerge from dynamically self-generated heterogeneity, where both the non-equilibrium history of the interface and wave reflections from finite boundaries, mediated by material inertia, play central roles. Specifically, the dynamics and statistics of large bursts reveal a timescale ∼H/cs, where cs is the shear wave-speed. We discuss the robustness of our findings against variations of the frictional parameters, most notably affecting the magnitude of frictional rate-weakening, as well as against different interfacial state evolution laws. Finally, we demonstrate a reverse transition in which statistical complexity disappears in favor of the spatially periodic traveling solution. Overall, our results elucidate how relatively simple physical ingredients can give rise to the emergence of slip complexity.
在摩擦系统中（非线性和耗散仅限于界面），统计复杂性（表现为各种可观测量的广泛分布）尚未得到理解。我们研究了在速度驱动、均匀（无随机扰动）不稳定摩擦系统中出现的这一问题，该系统高度为H。后者在连续尺度上被描述为一个现实的速率和状态摩擦界面本构框架，其中弹性摩擦不稳定性源于速率减弱摩擦。对于大H，最近的研究表明，此类摩擦系统会经历连续的粗化过程，直到进入一个具有空间周期性移动解的稳定状态。我们证明，当系统的高度与长度之比变得很小（这是各种工程和地球物理系统的特征）时，粗化效果会降低，并且会动态地避免周期性解。相反，与之前的报告一致，系统会进入一个随机的、统计稳定的状态。后者具有滑移脉冲，其滑移速率大于驱动速度，并且非平凡地分布。滑移破裂可以分为两类：以非传播为主的，伴有较小的总滑移量，以及以传播为主的，伴有较大的总滑移量。这些统计分布是由动态自生的异质性产生的，其中界面的非平衡历史和由材料惯性介导的有限边界的波反射在起关键作用。特别是，大的滑移破裂的动力学和统计特性揭示了一个时间尺度约为H/cs，其中cs是剪切波速度。我们讨论了研究结果对摩擦参数变化的鲁棒性，尤其是对摩擦率弱化的幅度的影响，以及对不同界面状态演化规律的影响。最后，我们展示了一个反向转变，其中统计复杂性让位于空间周期性的旅行解。总的来说，我们的研究结果阐明了相对简单的物理成分如何导致滑移复杂性的出现。
Configuration space of helical chiral self-assembly of micro/nano-fibers
Juntao Chen, Langquan Shui, Tao Ding, Ze Liu
doi:10.1016/j.jmps.2024.105708
微/纳米纤维螺旋手性自组装的构型空间
As undertaking various key functions, helical chiral structures are widely presented in nature. Herein, we develop a general theoretical framework to guide the formation of helical chiral structures through self-assembly of micro/nano-fibers driven by adhesion. By analyzing the spiral contact geometric characteristics of multiple fibers and extending the JKR theory, an analytical model for adhesive contact between helical interfaces is proposed. Further, the complete configuration space of self-assembled fibers depending on the adhesion work, elastic modulus, aspect ratio, and initial helix angle is theoretically analyzed. A diversity of helical configurations that far beyond existing experimental findings are predicted, which stems from the existence of multiple energy minimum points on the configuration-energy map. This work reveals the mechanism of adhesion-driven helical chiral structures, and provides theoretical foundation for guiding high-efficient fabrication of helical chiral structures through self-assembly method, which could promote the wide application of chiral structures in fields such as optics, catalysis and drug screening.
螺旋手性结构承担着多种关键功能，在自然界中广泛存在。在此，我们开发了一个通用的理论框架来指导通过由粘附驱动的微/纳米纤维自组装形成螺旋手性结构。通过对多纤维螺旋接触几何特性的分析，在JKR理论的基础上，提出了螺旋界面间粘接接触的解析模型。进一步，从理论上分析了自组装纤维随粘接功、弹性模量、纵横比和初始螺旋角的完整构形空间。由于构型-能量图上存在多个能量极小点，我们预测了远超现有实验结果的螺旋构型的多样性。本研究揭示了黏附驱动螺旋手性结构的机理，为指导利用自组装方法高效制备螺旋手性结构提供了理论基础，可促进手性结构在光学、催化、药物筛选等领域的广泛应用。
Mechanical characterization and constitutive modeling of additively-manufactured polymeric materials and lattice structures
Xiao Guo, Erdong Wang, Hang Yang, Wei Zhai
doi:10.1016/j.jmps.2024.105711
增材制造高分子材料和晶格结构的力学表征和本构建模
Additively manufactured polymeric lattice structures are being extensively studied, primarily because their mechanical properties can be tailored by controlling the unit cell geometry, giving them higher designability than stochastic materials. However, the inherent layer-wise additive manufacturing process affects the base material properties related to the printing direction, which in turn affects the macroscopic responses of the entire lattice materials. A robust understanding and modeling of lattice structures' elastic and plastic yield behavior in a homogenized approach are essential to enhance their design and analysis efficiency in engineering applications. In pursuit of this goal, a unified printing angle-dependent constitutive model of base materials is proposed in line with the tensile experimental data. The elastic material properties (elastic modulus, shear modulus, and Poisson's ratio), obtained through numerical simulations of one unit-cell with periodic boundary conditions, exhibit anisotropic properties, with the degree of anisotropy determined by the angle of the constituent members and base materials. Furthermore, both experimental and numerical results of lattices demonstrate anisotropic mechanical response under horizontal and vertical compression. Virtual multiaxial experiments are conducted through multi-cell numerical simulations, enabling the determination of initial yielding points of two different lattice structures (Kelvin and Simple cubic and body-centered cubic hybrid structures) under various loading conditions using a dissipation energy-based criterion. Overall, the multiaxial yield surface of the investigated lattices under various stress states, except for the isotropic principal stress plane, can be properly depicted by the Extended-Hill anisotropic yield criterion.
增材制造的聚合物晶格结构正在被广泛研究，主要是因为它们的机械性能可以通过控制单元胞的几何形状来定制，这使得它们比随机材料具有更高的可设计性。然而，固有的分层增材制造工艺会影响与打印方向相关的基材性能，进而影响整个晶格材料的宏观响应。在均匀化方法中对晶格结构的弹性和塑性屈服行为的稳健理解和建模对于提高其在工程应用中的设计和分析效率至关重要。为实现这一目标，结合拉伸实验数据，提出了统一的基材打印角度相关本构模型。通过周期性边界条件下的单胞数值模拟得到的弹性材料性能(弹性模量、剪切模量和泊松比)表现出各向异性，各向异性的程度由组成构件和基材的夹角决定。此外，实验结果和数值结果都表明，在水平和垂直压缩下，晶格的力学响应是各向异性的。通过多单元数值模拟进行了虚拟多轴实验，利用基于耗散能的准则确定了不同载荷条件下两种不同晶格结构(开尔文和简单立方以及体心立方混合结构)的初始屈服点。总体而言，除各向同性主应力面外，不同应力状态下晶格的多轴屈服面均可以用扩展-希尔各向异性屈服准则来描述。
International Journal of Plasticity
Tri-functional co-nanoprecipitates enhanced cryogenic ductility by inducing structural heterogeneity and refining nano-twins in a low-stacking-fault-energy 17Mn steel
Xiaoli Chu, Yu Li, Chun Xu, Wei Li, Bin Fu, Xiaoshuai Jia
doi:10.1016/j.ijplas.2024.104014
三官能团共纳米沉淀物通过诱导组织非均质性和细化纳米孪晶来增强低叠错能17Mn钢的低温延展性
In this study, an innovative tri-functional co-nanoprecipitation strategy was employed to enhance the mechanical properties of a low stacking-fault energy (SFE) 17Mn steel for cryogenic applications. By combining severe cold deformation and subsequent annealing, a hierarchical structure emerged, featuring (Ti, Nb)C carbide (∼10 nm) and Cu-rich intermetallic (∼2 nm) in the austenitic matrix with heterogeneous grain size distributions. The co-precipitation (CP) sample exhibited superior performance compared to single-precipitation (SP) steel, with a yield strength of ∼1150 MPa, tensile elongation of ∼44.8%, and an impact toughness of ∼110 J at liquid nitrogen temperature (LNT), even surpassing the base-17Mn steel. The CP-17Mn samples displayed a higher density and thinner nano-twins at larger strains, leading to a rapid increase in geometrically necessary dislocations (GNDs). The detrimental martensitic transformation was effectively suppressed during both tensile and impact tests. The observed inverse strength-ductility and strength-toughness trade-off can be attributed to the tri-functional co-precipitates’ roles: they provide disperse strengthening, induce structural heterogeneity, and act as effective barriers for twin thickening. The large-sized (Ti, Nb)C carbides facilitate grain refinement and pin boundary migration, while the smaller Cu-rich intermetallic inhibits the growth and thickening of nano-twins, preventing further dislocation movement due to their strong stress fields at the twin-precipitate interactions. This novel mechanism paves the way for developing higher-performance steels with fine and dense nano-twins at cryogenic conditions.
在这项研究中，采用一种创新的三功能共纳米沉淀策略来提高低温应用中低堆叠-故障能(SFE) 17Mn钢的力学性能。通过结合严重的冷变形和随后的退火，形成了一个层次结构，在奥氏体基体中具有(Ti, Nb)C碳化物(~ 10 nm)和富cu金属间化合物(~ 2 nm)，晶粒尺寸分布不均匀。与单析出(SP)钢相比，共析出(CP)样品表现出更好的性能，屈服强度为~ 1150 MPa，拉伸伸长率为~ 44.8%，在液氮温度(LNT)下的冲击韧性为~ 110 J，甚至超过了基17mn钢。在较大的应变下，CP-17Mn样品显示出更高的密度和更薄的纳米孪晶，导致几何必要位错(GNDs)迅速增加。在拉伸和冲击试验中，有害的马氏体相变得到有效抑制。所观察到的强度-延展性和强度-韧性的反向权衡可归因于三功能共析出物的作用:它们提供分散强化，诱导结构非均质性，并作为孪生增厚的有效屏障。大尺寸的(Ti, Nb)C碳化物促进晶粒细化和针脚边界迁移，而较小的富cu金属间化合物抑制纳米孪晶的生长和增厚，由于孪晶与析出相相互作用时的强应力场，阻止了进一步的位错运动。这一新的机制为在低温条件下开发具有精细和致密纳米孪晶的高性能钢铺平了道路。
Thin-Walled Structures
Exact three-dimensional elasticity analysis for buckling of composite laminated plates resting on viscoelastic foundation
Meisam Kheradpisheh, Mehdi Hojjati
doi:10.1016/j.tws.2024.112060
粘弹性基础上复合材料层合板屈曲的精确三维弹性分析
This paper aims to present novel exact solutions for the buckling of a laminated plate resting on the viscoelastic foundation with both normal and shear viscoelastic layers. The governing equations of plate buckling are derived using three-dimensional elasticity theory and state-space formulation. The normal and shear layers of the viscoelastic foundations are modeled using the generalized Maxwell model to represent both the elastic and viscose properties of the foundation. To couple the viscoelastic foundation equation with the buckling equation, Boltzmann’s superposition principle along with the Laplace transform is utilized. Then, the effects of geometry, relaxation modulus of normal and shear layers, viscosity, and time are investigated on the buckling load. The results reveal that the higher viscosity coefficient leads to a slower rate of change in the buckling loads. In addition, the viscoelastic properties have a significant impact on the buckling behavior of the plate. In this regard, the results show that instead of the expected second mode at a constant aspect ratio, the plate experiences the first mode as time passes. The computed results also show that there is a critical threshold. When the foundation stiffness exceeds this threshold, the conventional method of reducing the aspect ratio to prevent buckling not only proves ineffective in reducing the probability of buckling but also, in fact, leads to an increase in buckling occurrences. In addition to the analytical investigation, a finite element (FE) analysis is carried out to study the buckling response of the composite plate. The finite element results also show a reasonably good agreement with those of the analytical method.
本文旨在提出具有正弹性层和剪切粘弹性层的粘弹性基础上叠合板屈曲的新颖精确解。利用三维弹性理论和状态空间公式推导了板屈曲的控制方程。采用广义Maxwell模型对粘弹性地基的法向层和剪切层进行了建模，以反映地基的弹性和粘性。利用玻尔兹曼叠加原理和拉普拉斯变换将粘弹性基础方程与屈曲方程耦合起来。然后，研究了几何形状、法向层和剪切层松弛模量、黏度和时间对屈曲载荷的影响。结果表明，黏度系数越高，屈曲载荷的变化率越慢。此外，粘弹性特性对板的屈曲行为有显著影响。在这方面，结果表明，随着时间的推移，板经历的不是预期的第二模态，而是第一模态。计算结果也表明存在一个临界阈值。当基础刚度超过该阈值时，传统的减小长径比防止屈曲的方法不仅不能有效降低屈曲的概率，反而会导致屈曲发生的增加。在分析研究的基础上，对复合材料板的屈曲响应进行了有限元分析。有限元计算结果与解析计算结果也有较好的一致性。
Eccentric compression behavior of L-shaped column fabricated by thin-walled square steel tubes based on self-drilling screw connections
Xiaodun Wang, Jincheng Jiang, Yang Liu, Zhihua Chen
doi:10.1016/j.tws.2024.112063
基于自钻螺纹连接的薄壁方钢管l形柱偏心受压特性
In this study, a new L-shaped column fabricated by thin-walled square steel tubes (LFTST columns) based on self-drilling screw connections is proposed. The LFTST columns consisted of square steel tubes, U-shaped parts, angle parts, gusset plates, and self-drilling screw connections. LFTST columns possess several advantages including easy transportation, rapid assembly, and eco-friendliness. Consequently, they are suitable for low-rise buildings, such as village-building, low-rise dormitories, and low-rise office buildings. However, the compression behavior of LFTST columns remains silent. Five full-scale LFTST column specimens were subjected to eccentric compression tests. The variables under consideration included eccentricity (with values of 0mm, 40mm, and 80mm), thickness (2mm and 4mm), and the number of gusset plates (0, 1, and 3). The failure modes, bearing capacity, load-displacement response, and strain development of the LFTST specimens were obtained. Subsequently, finite element (FE) models of LFTST columns were established and used to analyze the eccentric compression behavior of LFTST columns. The FE modeling results agreed well with the experimental results. A detailed parameter analysis was conducted to evaluate the effects of various factors. These factors included the thickness of the plates (2mm, 3mm, and 4mm), the width of the gusset plates (100mm, 150mm, and 200mm), limb spacing values (0mm, 150mm, and 300mm), and eccentricity (0mm, 20mm, 40mm, 60mm, and 80mm). In addition, the calculation formula for estimating the ultimate bearing capacity of the LFTST columns was derived employing the double coefficient product method. The proposed formula was validated by experimental and FE results.
本文提出了一种基于自钻螺纹连接的薄壁方钢管l形柱(LFTST柱)。LFTST柱由方钢管、u型件、角件、扣板和自钻螺钉连接组成。LFTST柱具有运输方便、组装快速、环保等优点。因此，适用于低层建筑，如村舍、低层宿舍、低层写字楼等。然而，LFTST列的压缩行为保持沉默。对5个全尺寸LFTST柱试件进行了偏心压缩试验。考虑的变量包括偏心(0 mm、40mm和80mm)、厚度(2mm和4mm)和扣板数量(0、1和3)。得到了LFTST试件的破坏模式、承载能力、荷载-位移响应和应变发展。随后，建立了LFTST柱的有限元模型，并对LFTST柱的偏心受压行为进行了分析。有限元模拟结果与试验结果吻合较好。对各因素的影响进行了详细的参数分析。这些因素包括板的厚度(2mm, 3mm和4mm)，扣板的宽度(100mm, 150mm和200mm)，肢间距值(0mm, 150mm和300mm)和偏心率(0mm, 20mm, 40mm, 60mm和80mm)。此外，采用双系数乘积法推导了LFTST柱极限承载力的计算公式。实验和有限元结果验证了所提公式的正确性。
