今日更新：International Journal of Solids and Structures 2 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 StructuresPlanar piezoelectric metamaterials: Sound transmission and applicable frequency range in oblique incidenceGuosheng Ji, John Huberdoi:10.1016/j.ijsolstr.2023.112640平面压电超材料：斜入射中的声音传输和适用频率范围Frequency limit and applicable frequency range of planar piezoelectric metamaterials connected to external circuits have not been well defined in estimating the sound transmission loss. This article extends the classical transfer matrix method for use in evaluating the sound transmission of thin-plate piezoelectric metamaterials in oblique incidence. Using the Kirchhoff thin plate theory, a modified transfer matrix method that takes factors of external circuits into consideration is developed for attenuation and control of acoustic waves. Several vibro-acoustic analytical models are compared, including the Kirchhoff thin plate theory, the Reissner–Mindlin thick plate theory and the theory of wave propagation in elastic solids. These theories are used to determine the dispersion relation, coincidence and transition frequency of thin and thick plate theories in analyzing piezoelectric acoustic metamaterials, alongside a validation using the finite element method. Then acoustic properties of piezoelectric plates connected to passive external circuits are studied parametrically with both dimensional and dimensionless variables based on an equivalent Kirchhoff plate approximation. The findings show that external electrical impedance alone can be used to adjust the resonance frequency over a broad range and thereby control sound transmission loss. This provides considerable flexibility in modifying the acoustic properties of the piezoelectric metamaterial in comparison to traditional, fixed-structure metamaterials. The study indicates a straightforward and powerful analytical approach for the optimization of acoustic insulation using thin-plate piezoelectric metamaterials.在估算声音传输损耗时，与外部电路连接的平面压电超材料的频率限制和适用频率范围尚未得到很好的定义。本文扩展了经典的传递矩阵法，用于评估斜入射情况下薄板压电超材料的声音传输。利用基尔霍夫薄板理论，开发了一种考虑到外部电路因素的修正传递矩阵法，用于声波的衰减和控制。比较了几种振动声学分析模型，包括基尔霍夫薄板理论、赖斯纳-明德林厚板理论和弹性固体中的波传播理论。在分析压电声学超材料时，这些理论用于确定薄板和厚板理论的频散关系、重合度和过渡频率，同时使用有限元方法进行验证。然后，基于等效基尔霍夫板近似，使用有维变量和无维变量对连接到无源外部电路的压电板的声学特性进行了参数化研究。研究结果表明，仅外部电阻抗就能在很大范围内调节共振频率，从而控制声音传输损耗。与传统的固定结构超材料相比，这为改变压电超材料的声学特性提供了相当大的灵活性。研究表明，使用薄板压电超材料优化隔音效果的分析方法简单而强大。Nonlinear effect of rigidity and correlated disorder on network fractureZhao-Dong Ding, Da-Wei Lindoi:10.1016/j.ijsolstr.2024.112644刚性和相关无序对网络断裂的非线性影响Mechanical rigidity and disorder are two important parameters that influence the failure process of solid materials. We investigate the nonlinear mechanics under their coupled effect as well as the influence of disorder’s spatial correlation with 2-D network model. The strain–stress relations present strong nonlinearity and rigidity regain phenomenon when there is strong disorder and high rigidity. The correlation of disorder would weaken the effect and has a great influence on the peak stress, initial stiffness, and system toughness. The crossover of power-law exponents of avalanches is observed with consideration of disorder and the transitions in the cluster distribution induced by correlated disorder disappear as the system rigidity decrease. We conclude that although the disorder can be seen as a reduction of average coordinated number for small rupture thresholds system, the correlated disorder still has a great influence on the failure behaviors of heterogeneous materials.机械刚性和无序是影响固体材料失效过程的两个重要参数。我们利用二维网络模型研究了它们耦合效应下的非线性力学以及无序空间相关性的影响。当存在强无序和高刚性时，应变-应力关系呈现出强烈的非线性和刚性恢复现象。无序的相关性会削弱这种效应，并对峰值应力、初始刚度和系统韧性产生很大影响。在考虑无序的情况下，可以观察到雪崩幂律指数的交叉，并且随着系统刚度的降低，由相关无序引起的簇分布转变也会消失。我们的结论是，虽然无序可以被看作是小断裂阈值系统平均配位数的减少，但相关无序仍对异质材料的破坏行为有很大影响。Journal of the Mechanics and Physics of SolidsForce relaxation response in the poroelastic axisymmetric Boussinesq problem for an indenter of arbitrary profiles I: Permeable and impermeable surface drainage conditionsMing Liu, Xin Wendoi:10.1016/j.jmps.2023.105532任意轮廓压头的孔弹性轴对称布西内斯克问题中的力松弛响应 I．透水和不透水表面排水条件In this study, we have derived a theoretical solution for the poroelastic axisymmetric Boussinesq problem when an indenter with arbitrary profiles is subjected to step displacement loading. The analysis is conducted within the framework of Biot’s theory, employing the McNamee–Gibson displacement function method. We explore two distinct scenarios for surface drainage boundary conditions: one where the surface allows full permeability and another where it is fully impermeable. The formulation of the mechanical boundary condition at the surface relies on an equation that establishes the relationship between the depth of indentation and the contact radius. Our solution encompasses two aspects: force asymptotes at the undrained and drained limits, and a normalized force relaxation that accounts for transient responses. Specific findings are presented for three indenter shapes: paraboloidal, conical, and cylindrical. Of particular significance, we demonstrate that for these specific indenter shapes, the normalized force relaxation at ω=0 can be expressed in closed form in the Laplace domain. In addition to this analytical breakthrough, we conducted numerical simulations employing actual indenters. Remarkably, the normalized force relaxation curves from actual indenters show negligible dependence on material properties and closely align with our closed-form solution at ω=0. This finding suggests that the closed-form solution could act as a universal master curve capable of characterizing the normalized force relaxation response in instances of a real indenter, irrespective of material properties.在本研究中，我们推导出了当任意轮廓的压头受到阶跃位移加载时，孔弹性轴对称布辛斯问题的理论解法。分析是在 Biot 理论框架内，采用 McNamee-Gibson 位移函数法进行的。我们探讨了表面排水边界条件的两种不同情况：一种是表面允许完全渗透，另一种是完全不渗透。表面力学边界条件的表述依赖于建立压痕深度与接触半径之间关系的方程。我们的解决方案包括两个方面：未排水和排水极限的力渐近线，以及考虑瞬态响应的归一化力松弛。具体研究结果针对三种压头形状：抛物面、圆锥形和圆柱形。特别重要的是，我们证明了对于这些特定形状的压头，ω=0 时的归一化力松弛可以在拉普拉斯域中以封闭形式表示。除了这一分析上的突破，我们还利用实际压头进行了数值模拟。值得注意的是，实际压头的归一化力松弛曲线对材料特性的依赖性可以忽略不计，并且与我们在 ω=0 时的闭式求解结果非常吻合。International Journal of PlasticityStress-induced detwinning/reorientation of hierarchically twinned martensite and deformation micro-mechanism in Ni52Mn27Ga17Co4 shape memory alloys: Experimental and phase-field studiesL. Liang, W. Tong, X. Wang, H.Z. Hu, H.J. Wang, J. Tian, L.M. Pengdoi:10.1016/j.ijplas.2023.103870Ni52Mn27Ga17Co4 形状记忆合金中分层孪晶马氏体的应力诱导解旋/重取向及变形微观机制：实验和相场研究Mechanical training via cyclic loading and unloading was widely used in NiMnGa shape memory alloys (SMAs) to create single or double variant states for reducing the resistance to variant reorientation and thus achieving a maximum shape memory strain. In this work, an effort was made to reveal the deformation mechanism of a polycrystalline Ni52Mn27Ga17Co4 high-temperature SMAs consisting of non-modulated (NM) martensite with uniform orientation and surrounding γ precipitates. The NM martensite microstructure was characterized as a self-accommodated hierarchical twinned-structure prior to deformation. Based on the interrupted in-situ EBSD measurements and phase-field simulations, it was demonstrated that the compressive loading resulted in the thickening of the stress-favored variants with the <001>NM direction perpendicular to compression axis at different dimensional scales. The path consisted of two subsequent processes–first detwinning of the nano-lamellae within one micro-variant through inter-lamellae boundary motion, and then reorientation of micro-variants through inter-plate boundary motion. The Schmid factor and preferred orientation of nano-lamellae (or strain accommodation) dominated the entire detwinning/reorientation process of NM martensite. As a result, the hierarchically twinned microstructure almost evolved into a single-variant state with the disappearance of packet boundaries. The ductile γ phase with network structure possessed more excellent strain-accommodated ability to the macroscopic deformation, hence significantly enhancing the mechanical properties including the ultimate compressive strength and elongation of NiMnGa SMAs.在镍锰镓形状记忆合金（SMA）中，通过循环加载和卸载进行的机械训练被广泛用于创建单或双变体状态，以降低变体重新定向的阻力，从而获得最大形状记忆应变。本研究试图揭示一种多晶镍52Mn27Ga17Co4高温SMA的变形机理，这种SMA由取向均匀的非调制（NM）马氏体和周围的γ析出物组成。NM 马氏体微观结构的特征是变形前的自容纳分层孪晶结构。根据中断的原位 EBSD 测量和相场模拟，证明了压缩加载导致应力偏好变体增厚，<001>NM 方向在不同尺寸尺度上与压缩轴垂直。该路径由两个后续过程组成--首先通过层间边界运动使一个微变体中的纳米层脱离，然后通过板间边界运动使微变体重新定向。Schmid 因子和纳米薄片的优先取向（或应变容纳）主导了整个 NM 马氏体的分离/重新取向过程。因此，随着包边界的消失，分层孪晶微观结构几乎演变为单一变体状态。具有网络结构的韧性 γ 相对宏观变形具有更出色的应变容纳能力，从而显著提高了镍锰镓 SMA 的力学性能，包括极限抗压强度和伸长率。Thin-Walled StructuresA high-efficiency material deployment design method assisted with multiscale analysisShengda Jiang, Ji Hedoi:10.1016/j.tws.2023.111540借助多尺度分析的高效材料调配设计方法Efficient deployment of the right materials at the right place is a nontrivial problem. Structural components can achieve superior mechanical properties through tunable material deployment. However, such a structure-property-performance relationship is not explicit and requires the trial-and-error procedure. Discovering this relationship is extremely challenging due to a large number of possible material microstructures and deployed position combinations, and the search for the optimal design is computationally expensive. In this study, a data-driven approach is proposed to efficiently discover the underlying relationship between the deployment of a specific material microstructure and the final structural performance. The uniaxial tension of a perforated composite plate was used as a demonstrator. A high-fidelity representative volume element of a unidirectional fiber reinforced composite was constructed and utilized to calibrate the phenomenological constitutive model. A data compression algorithm was applied to the structure geometry in a finite element simulation to mechanically group similar regions and reduce dimensionality. After optimization, the calculated scenarios were selected based on the target performance. High-efficiency multiscale analysis was subsequently conducted on the selected conceptual designs to reveal the micro-deformation mechanism and interpret the interaction between the fibers and the matrix.在正确的位置高效地使用正确的材料是一个非同小可的问题。结构组件可以通过可调整的材料配置获得优异的机械性能。然而，这种结构-性能关系并不明确，需要反复试验。由于存在大量可能的材料微结构和部署位置组合，发现这种关系极具挑战性，而且寻找最佳设计的计算成本很高。本研究提出了一种数据驱动方法，以有效发现特定材料微结构的部署与最终结构性能之间的潜在关系。以穿孔复合板的单轴拉伸为例进行说明。构建了单向纤维增强复合材料的高保真代表性体积元素，并利用该元素校准了现象构成模型。在有限元模拟中，对结构几何形状采用了数据压缩算法，以便对相似区域进行机械分组并减少尺寸。经过优化后，根据目标性能选择了计算方案。随后，对选定的概念设计进行了高效多尺度分析，以揭示微变形机制并解释纤维与基体之间的相互作用。New design and energy absorption characteristic study of bionic beetle's elytra under axial compressionTieping Wei, Mengzhi Zhang, Shouqiang Lin, Jianhua Ye, Xiaolei Yan, Jinquan Guodoi:10.1016/j.tws.2023.111543轴向压缩下仿生甲虫叶甲的新设计和能量吸收特性研究Inspired by the microstructure of the beetle's elytra, a new bionic polycellular tube protective structure based on the fractal principle was proposed in this paper, and its energy absorption characteristics were studied. Firstly, the typical microstructures of two-branch structure (type A), three-branch structure (type B) and mixed-branch structure (type C) of the beetle's elytra were extracted. Based on that, three types of the bionic multicellular thin-walled circular tube (BMTC) were designed, and the reliability of finite element models was verified by experiments. Secondly, the energy absorption characteristics and crushing mechanism of three groups of BMTCs were compared and analyzed by LS-DYNA software, and the analytical expression of mean crushing force (Fm) for BMTCs was established. The results show that the energy absorption structures of type B have better comprehensive energy absorption characteristics. Compared with the traditional ribbed structure, specific energy absorption (SEA) of BMTCs is increased by 36.75%. In addition, when the central column is connected to the three ribs, the central column has the best deformation resistance. Moreover, the theoretical solutions matched well with the results of numerical simulation. Consequently, the research results provide inspiration for the design of energy absorption protection devices, and theoretical guidance for the analysis of energy absorption characteristics.受甲虫蜕皮微结构的启发，本文提出了一种基于分形原理的新型仿生多细胞管保护结构，并对其能量吸收特性进行了研究。首先，提取了甲虫背甲的双支结构（A 型）、三支结构（B 型）和混合支结构（C 型）的典型微观结构。在此基础上，设计了三种类型的仿生多细胞薄壁圆管（BMTC），并通过实验验证了有限元模型的可靠性。其次，利用 LS-DYNA 软件对比分析了三组 BMTC 的吸能特性和破碎机理，建立了 BMTC 平均破碎力（Fm）的解析表达式。结果表明，B 型吸能结构具有更好的综合吸能特性。与传统的带肋结构相比，BMTC 的比能量吸收（SEA）提高了 36.75%。此外，当中心柱与三条肋骨连接时，中心柱的抗变形能力最佳。此外，理论解与数值模拟的结果非常吻合。因此，研究结果为吸能保护装置的设计提供了启发，也为吸能特性分析提供了理论指导。The thickness effect of rubbery nanofibrous mat on Modes I–II fracture mechanism of composite laminatesHesamaldin Saghafi, Isa Ahmadi, Ramin Khamedi, Hamed Saghafi, Milad Saeedifar, Tommaso Maria Brugo, Emanuele Maccaferri, Jacopo Ortolani, Francesco Mongioì, Laura Mazzocchetti, Andrea Zucchellidoi:10.1016/j.tws.2024.111556纳米纤维橡胶垫对复合材料层压板 I-II 模态断裂机制的厚度效应This study investigates the effect of the interleaving nanofibers, made of NBR/PCL blend, on the interlaminar fracture toughness of carbon/epoxy laminates. Different nanomat thicknesses, ranging from 20 μm to 120 μm, were tested at Mode-I and mode-II and results were compared to the non-modified laminates. Acoustic Emission (AE) technique was used to assess the influence of interleaving nanofibers on dominant damage modes of the specimens, i.e., matrix cracking, fiber/matrix debonding, and fiber breakage. Moreover, the damage mechanism and the nanofiber toughening contribution were investigated by means of crack path and surface analysis. Results indicated that the optimum nanomat thickness for mode-I is 40 μm (GI,R = + 333 %), while for mode-II is 20 μm (GII,R = + 43 %). The study also confirmed by AE the significant impact of nanofibers on various damage modes, especially during mode-I loading.本研究探讨了由 NBR/PCL 混合物制成的交错纳米纤维对碳/环氧层压板层间断裂韧性的影响。在模式 I 和模式 II 下测试了不同厚度的纳米纤维（从 20 μm 到 120 μm），并将结果与未改性层压板进行了比较。采用声发射（AE）技术评估了交错纳米纤维对试样主要损伤模式（即基体开裂、纤维/基体脱粘和纤维断裂）的影响。此外，还通过裂纹路径和表面分析研究了损伤机理和纳米纤维的增韧作用。结果表明，模式 I 的最佳纳米垫厚度为 40 μm（GI,R = + 333 %），而模式 II 的最佳纳米垫厚度为 20 μm（GII,R = + 43 %）。研究还通过 AE 证实了纳米纤维对各种损伤模式的显著影响，尤其是在模式-I 加载期间。来源：复合材料力学仿真Composites FEM
