【新文速递】2024年3月29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 4 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Elastic properties and compressive mechanical behaviour of closed-cell porous materials: Effect of microstructural morphology

Yulia Pirogova, Mikhail Tashkinov, Ilia Vindokurov, Vadim V. Silberschmidt

doi:10.1016/j.ijsolstr.2024.112791

闭孔多孔材料的弹性特性和压缩机械性能：微结构形态的影响

This paper studies the effect of different combinations of morphological parameters of porous closed-cell materials on their elastic properties and mechanical behaviour. Three-dimensional representative volumes of porous media with different polyhedral void shapes are investigated, considering variation of statistical realisations of morphological features, such as shape, size and distribution of pores. Description of morphology of each investigated representative volume is formalized using second- and fourth-order correlation functions. The effective properties of representative volumes are calculated with finite-element analysis. Additionally, samples of the studied models were additively manufactured with polystyrene, using fused filament fabrication (FFF/FDM) 3D-printing technique, and subjected to compression. Experimental results for elastic mechanical properties and distributions of strain fields on the surface of the samples, obtained with micro-DIC (digital image correlation), are compared with results of numerical finite-element computations. This is accompanied by analysis of internal-stress distributions to assess the mechanical state of the structures. Patterns and trends observed in mechanical responses of porous materials depending on their different morphological parameters are outlined and discussed.

本文研究了多孔闭孔材料形态参数的不同组合对其弹性特性和机械行为的影响。研究了具有不同多面体空隙形状的多孔介质的三维代表体积，考虑了形态特征（如孔的形状、大小和分布）的统计现实变化。使用二阶和四阶相关函数对每个研究代表体积的形态进行了形式化描述。代表体积的有效特性是通过有限元分析计算得出的。此外，使用熔融长丝制造（FFF/FDM）三维打印技术，用聚苯乙烯加成制造了所研究模型的样品，并对其进行了压缩。利用微型 DIC（数字图像相关性）获得的弹性机械性能和样品表面应变场分布的实验结果与有限元数值计算结果进行了比较。同时还对内部应力分布进行了分析，以评估结构的机械状态。概述并讨论了多孔材料的机械响应模式和趋势，这些模式和趋势取决于其不同的形态参数。

Journal of the Mechanics and Physics of Solids

Large strain micromechanics of thermoplastic elastomers with random microstructures

Hansohl Cho, Jaehee Lee, Jehoon Moon, Elmar Pöselt, Pieter J. in’t Veld, Gregory C. Rutledge, Mary C. Boyce

doi:10.1016/j.jmps.2024.105615

具有随机微结构的热塑性弹性体的大应变微机械学

Thermoplastic polyurethanes (TPU) are block copolymeric materials composed of plastomeric “hard” and elastomeric “soft” domains, by which they exhibit highly resilient yet dissipative large deformation features depending on volume fractions and microstructures of the two distinct domains. Here, we develop a new methodology to explore the microscopic deformation mechanisms in TPU materials with highly disordered microstructures. We propose new micromechanical models for randomly dispersed (or occluded) as well as randomly continuous hard domains (and mixtures of both dispersed and continuous hard domains), each within a continuous soft structure as widely found in representative TPU materials over a wide range of volume fractions, v_hard = 26.9% to 52.2%. The micromechanical modeling results are compared to experimental data on the macroscopic large strain behaviors reported previously (Cho et al. 2017). We explore the role of the dispersed vs. continuous nature of the geometric features of the random microstructures on shape recovery and energy dissipation at the microstructural level in these phase-separated copolymeric materials.

热塑性聚氨酯(TPU)是由塑性“硬”域和弹性“软”域组成的嵌段共聚物材料，通过这种方法，它们表现出高弹性但耗散的大变形特征，这取决于这两个不同域的体积分数和微观结构。本文开发了一种新的方法来探索具有高度无序微观结构的TPU材料的微观变形机制。我们提出了新的微观力学模型，用于随机分散(或闭塞)以及随机连续的硬域(以及分散和连续硬域的混合物)，每个都位于代表性TPU材料中广泛发现的连续软结构中，其体积分数范围很大，v_hard = 26.9%到52.2%。微观力学建模结果与先前报道的宏观大应变行为的实验数据进行了比较(Cho et al. 2017)。我们探讨了这些相分离共聚物材料中随机微观结构几何特征的分散与连续性对微观结构水平的形状恢复和能量耗散的作用。

Mechanistic understanding of microstructural effects on the thermal fatigue resistance of solder joints

Yilun Xu, Jingwei Xian, Richard J. Coyle, Christopher M. Gourlay, Fionn P.E. Dunne

doi:10.1016/j.jmps.2024.105623

从机理上理解微结构对焊点热疲劳抗性的影响

This paper uses a multi-scale crystal plasticity modelling approach to investigate the role of microstructure in the damage of Sn-3Ag-0.5Cu (wt%, SAC305) solder joints subject to thermal cycling. Faithful microstructure modelling has been developed to explicitly represent the complex microstructure characterized in the experiments. The mechanisms for the experimental finding that single crystal joints systematically outperform interlaced and beachball joints, in terms of damage development during thermal cycling, are found to be the localization of stored energy due to the grain boundaries. Interlaced regions, however, benefit the lifetime of solder joints versus a beachball microstructure by virtue of energy diffusion. The modelling results, together with experimental characterization, provide practical suggestions on how the microstructure could be designed to optimize the in-service lifetime of solder joints subject to thermal fatigue.

本文采用多尺度晶体塑性建模方法来研究微观结构在热循环条件下锡-3Ag-0.5Cu（重量百分比，SAC305）焊点损坏中的作用。我们建立了可靠的微观结构模型，以明确表示实验中的复杂微观结构特征。实验发现，单晶焊点在热循环过程中的损伤发展情况系统性地优于交错焊点和滩球焊点，其机理是由于晶界导致了存储能量的局部化。然而，交错区与滩球状微结构相比，由于能量扩散，焊点的使用寿命更长。建模结果和实验表征为如何设计微结构以优化受热疲劳影响的焊点的在役寿命提供了实用建议。

Towards design of a gradient locally resonant acoustic metasurface for negative reflection

X. Kuci, M.G.D. Geers, V.G. Kouznetsova

doi:10.1016/j.jmps.2024.105632

设计用于负反射的梯度局部共振声学元表面

Gradient acoustic metasurfaces are a class of subwavelength metamaterials that provide unprecedented opportunities to control the direction of reflected and refracted waves, including negative angles in accordance with the diffraction theory and generalized law of reflection. This opens new possibilities in designing metasurfaces for many practical applications in wave engineering. In this work, locally resonant acoustic metamaterials are considered as the building units of the metasurface, which owe their favorable properties to local resonances at the microstructural level. Non-trivial reflection angles are realized by introducing suitable phase modulations along the wave path. The required phase shift is achieved through the variation of geometrical and material parameters of the metamaterial unit cells. The negative reflection of ultrasound waves is demonstrated numerically by means of a finite-element analysis of a fluid-metasurface-solid structure. The results of this study provide new insights and detailed guidelines for designing metasurfaces for controllable acoustic wave reflection.

梯度声超表面是一类亚波长超材料，它提供了前所未有的机会来控制反射波和折射波的方向，包括根据衍射理论和广义反射定律控制负角度。这为超表面设计在波工程领域的许多实际应用提供了新的可能性。在这项研究中，局部共振声超材料被视为超表面的构建单元，其有利特性归功于微结构层面的局部共振。通过沿波路引入适当的相位调制，可实现非三维反射角。通过改变超材料单元格的几何和材料参数，可实现所需的相移。通过对流体-超表面-固体结构进行有限元分析，对超声波的负反射进行了数值演示。研究结果为设计可控声波反射超表面提供了新的见解和详细的指导。

Inverse design of three-dimensional multicellular biobots with target functions

Hui-Kai Zhang, Bo-Wen Xu, Zi-Yao Jia, Bo Li, Xi-Qiao Feng

doi:10.1016/j.jmps.2024.105634

具有目标功能的三维多细胞生物机器人的逆向设计

Hybrid living biobots consisting of active cells hold promise for significant applications as, for example, intelligent devices in medical engineering and organisms with specific functions in synthetic biology. However, the design and creation of living biobots with various cells remain a challenge. In this paper, we propose a three-dimensional inverse optimization strategy based on the pixel topology optimization method, to design self-propelled living biobots with the function of biomechanical actuations. For illustration, we design several biobots composed of active and passive elements that mimic cardiomyocytes and passive epidermal cells sourced from such as Xenopus Laevis, human induced pluripotent stem cells or neonatal rats. Their topologies are optimized by implementing the active constitutive relations of cells into the multicellular topological interpolation model. Effects of nutrient concentrations, elasticity, and anisotropic contraction of cardiomyocytes on the topologies and functionalities of the biobots are examined. In addition, we unveil the living topological interfaces generated by the collective actuations of the optimized biobots. We show a potential of collective biobots for high-throughput drug screening owing to their distinct biomechanical responses under healthy and sick conditions. The proposed inverse optimization method can be extended to design various functional multicellular biological systems, which impacts the studies of organ development, synthetic biology, and medical engineering.

由活性细胞组成的混合活体生物机器人有望作为医疗工程中的智能设备和合成生物学中具有特定功能的生物体等得到广泛应用。然而，设计和创建具有各种细胞的活体生物机器人仍然是一项挑战。在本文中，我们提出了一种基于像素拓扑优化方法的三维逆向优化策略，用于设计具有生物力学驱动功能的自推进活体生物机器人。为了说明这一点，我们设计了几种由主动和被动元件组成的生物机器人，它们模仿了心肌细胞和被动表皮细胞，这些细胞来源于章鱼、人类诱导多能干细胞或新生大鼠。通过在多细胞拓扑插值模型中实施细胞的主动构成关系，对它们的拓扑结构进行了优化。我们研究了营养浓度、弹性和心肌细胞各向异性收缩对生物机器人拓扑结构和功能的影响。此外，我们还揭示了优化生物机器人的集体行动所产生的活拓扑界面。我们展示了集体生物机器人在高通量药物筛选方面的潜力，因为它们在健康和生病条件下的生物力学反应各不相同。所提出的反向优化方法可扩展到设计各种功能性多细胞生物系统，从而影响器官发育、合成生物学和医学工程的研究。

Thin-Walled Structures

Bayesian optimization of origami multi-cell tubes for energy absorption considering mixed categorical-continuous variables

Na Qiu, Zhuoqun Yu, Depei Wang, Mingwei Xiao, Yiming Zhang, Nam H. Kim, Jianguang Fang

doi:10.1016/j.tws.2024.111799

考虑分类-连续混合变量的能量吸收折纸多孔管贝叶斯优化技术

Multi-cell structures have been widely utilized in energy-absorbing applications for their lightweight and superior mechanical properties. However, they may produce high peak forces that are harmful to occupant safety during a vehicle collision. In addition, the naturally formed folding and global bending modes under axial loads can significantly restrict their energy-absorbing capability. In this study, a novel origami multi-cell structure is proposed to avoid excessive peak loads and at the same time to guide the deformation mode to improve the energy-absorbing capability. Four cross-sectional types of origami multi-cell structures are investigated experimentally and numerically. The results indicated that the web-to-web (W2W) type origami multi-cell structures are most promising for energy absorption, while web-to-corner (W2C) structures yield low peak forces and excellent deformation modes in our study cases. To further exploit the potential of these structures, multi-objective optimization is required to consider the conflicting objectives of maximizing energy-absorbing capability and minimizing the peak force. However, it is challenging for traditional optimization to deal with continuous, integer, and categorical variables simultaneously. Therefore, the Bayesian optimization method based on the Hamming distance is utilized to handle mixed categorical-continuous variables to optimize origami multi-cell tubes. The optimization results indicated that the optimal origami W2C can decrease the peak force by 30% while keeping a similar level of specific energy-absorbing capability compared with the traditional W2C. Moreover, the optimal origami W2C structure can improve the energy absorption by 40% compared with the origami W2C baseline design.

多孔结构因其轻质和卓越的机械性能而被广泛应用于能量吸收领域。然而，在车辆碰撞过程中，它们可能会产生对乘员安全有害的高峰值力。此外，在轴向载荷作用下自然形成的折叠和整体弯曲模式也会极大地限制其能量吸收能力。本研究提出了一种新型折纸多单元结构，以避免过高的峰值载荷，同时引导变形模式，提高能量吸收能力。实验和数值研究了四种截面类型的折纸多单元结构。结果表明，腹板到腹板（W2W）类型的折纸多孔结构最有希望吸收能量，而腹板到角落（W2C）结构在我们的研究案例中产生了较低的峰值力和出色的变形模式。为了进一步挖掘这些结构的潜力，需要进行多目标优化，以考虑能量吸收能力最大化和峰值力最小化这两个相互冲突的目标。然而，传统的优化方法很难同时处理连续、整数和分类变量。因此，基于Hamming距离的贝叶斯优化方法被用来处理混合的分类-连续变量，以优化折纸多孔管。优化结果表明，与传统的 W2C 相比，最优的折纸 W2C 可将峰值力降低 30%，同时保持相似水平的比能量吸收能力。此外，与折纸 W2C 基准设计相比，最佳折纸 W2C 结构可将能量吸收能力提高 40%。