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

International Journal of Solids and Structures

Machine learning predictions on the compressive stress–strain response of lattice-based metamaterials

Lijun Xiao, Gaoquan Shi, Weidong Song

doi:10.1016/j.ijsolstr.2024.112893

格基超材料压缩应力-应变响应的机器学习预测

Predicting the stress–strain curve of lattice-based metamaterials is crucial for their design and application. However, the complex nonlinear relationship between the mesoscopic structure of lattice materials and their macroscopic mechanical behavior makes prediction challenging. In this study, beam element models of over 20,000 lattice structures were established using Python scripts, and calculations were performed in ABAQUS to obtain training and testing datasets. The spatial features of each lattice-based metamaterial were then encoded into a graph, a data structure recognizable by machine learning algorithm. Utilizing machine learning methods, a Structure to Sequence Neural Network was constructed and trained, achieving rapid prediction of the compressive stress–strain curves for lattice-based metamaterials. Afterwards, several lattice structures were randomly selected and 3D printed. The accuracy of the simulation results as well as machine learning predictions was validated through quasi-static compression experiments. It is revealed that the proposed Neural Network model outperforms the traditional Artificial Neural Networks as the errors are reduced while the Coefficient of Determination is higher. The results demonstrate the accurate fitting between the complex spatial features of the lattice-based metamaterials and their stress–strain curves, which provides a potential methodology for inverse optimization of the lattice-based metamaterials in the future.

预测晶格基超材料的应力应变曲线对其设计和应用至关重要。然而，晶格材料的介观结构与其宏观力学行为之间复杂的非线性关系使得预测具有挑战性。在本研究中，使用Python脚本建立了20000多个点阵结构的梁单元模型，并在ABAQUS中进行计算，获得训练和测试数据集。然后将每个基于晶格的超材料的空间特征编码成图，这是一种由机器学习算法可识别的数据结构。利用机器学习方法，构建并训练了结构到序列的神经网络，实现了晶格基超材料压缩应力-应变曲线的快速预测。然后，随机选择几个点阵结构进行3D打印。通过准静态压缩实验验证了仿真结果和机器学习预测的准确性。结果表明，该神经网络模型在误差减小的同时具有较高的决定系数，优于传统的人工神经网络。结果表明，晶格基超材料的复杂空间特征与其应力应变曲线之间具有较好的拟合性，为未来晶格基超材料的逆优化提供了一种潜在的方法。

Journal of the Mechanics and Physics of Solids

Mechanics of gradient nanostructured metals

Yin Zhang, Zhao Cheng, Ting Zhu, Lei Lu

doi:10.1016/j.jmps.2024.105719

梯度纳米结构金属的力学

The emergence of heterogeneous nanostructured materials (HNMs) offers exciting opportunities to achieve outstanding mechanical properties. Among these materials, gradient nanotwinned (GNT) Cu is a prominent class of HNMs, demonstrating superior strengths by gaining extra strengths compared to non-gradient counterparts. Its layered gradient structure provides a simplified quasi-one-dimensional model system for understanding the extra strengthening effects of structural gradients and resulting plastic strain gradients. This paper presents a comprehensive report for recent experimental and modeling studies on the mechanics of GNT Cu, covering advances in controlled material processing, back stress measurement, deformation field characterization, dislocation microstructure analysis, and strain gradient plasticity modeling. These studies unveil the spatiotemporal evolution of both plastic strain gradients and extra back stresses originating from structural gradients. Direct connections are established between the sample-level extra strength of GNT Cu and the synergistic strengthening effects induced by local nanotwin structures and their gradients. We emphasize the critical role of the representative volume element size in assessing the effects of plastic strain gradient and extra back stress. Moreover, lower-order strain gradient plasticity models are validated through experimental characterizations of GNT Cu, paving the way for future investigation into the mechanics of gradient nanostructured metals. Finally, we provide an outlook on research needs for understanding the mechanics of gradient nanostructured metals and, more broadly, HNMs, towards achieving exceptional mechanical properties.

非均相纳米结构材料(HNMs)的出现为实现优异的机械性能提供了令人兴奋的机会。在这些材料中，梯度纳米孪晶(GNT) Cu是一类突出的hnm，与非梯度材料相比，通过获得额外的强度，显示出优越的优势。它的分层梯度结构为理解结构梯度和由此产生的塑性应变梯度的额外强化效应提供了一个简化的准一维模型系统。本文介绍了近年来GNT Cu力学的实验和模型研究的综合报告，涵盖了受控材料加工，背应力测量，变形场表征，位错微观结构分析和应变梯度塑性建模的进展。这些研究揭示了塑性应变梯度和由结构梯度引起的额外背应力的时空演变。建立了GNT Cu的样品级额外强度与局部纳米孪晶结构及其梯度引起的协同强化效应之间的直接联系。我们强调了代表性体积单元尺寸在评估塑性应变梯度和额外背应力影响中的关键作用。此外，通过GNT Cu的实验表征验证了低阶应变梯度塑性模型，为进一步研究梯度纳米结构金属的力学奠定了基础。最后，我们展望了研究需求，以了解梯度纳米结构金属的力学，更广泛地说，hnm，以实现卓越的力学性能。

Fatigue-resistant adhesion through high energy barriers

Qi Li, Chao Ma, Yunfeng He, Pengyu Lv, Huiling Duan, Wei Hong

doi:10.1016/j.jmps.2024.105722

通过高能量垒抗疲劳粘附

The applications of soft materials in various fields often require interfacial adhesion to sustain prolonged static or cyclic loads, whereas most existing adhesives are susceptible to fatigue failure. Unlike in a quasistatic debonding process, which depends more on the average resistance, the key to preventing fatigue crack propagation is to build up high energy barriers locally. Herein, we invoke three types of structural designs to induce large energy barriers at the interface to achieve fatigue-resistant adhesion. By varying the local bending stiffness of the backing layer, locally altering the fracture mode through kirigami patterns, or hindering crack initiation with simple edge notches, we enhanced the fatigue thresholds of various adhesives against peeling by several orders of magnitude, reaching record-breaking values. To verify the proposed mechanism and reveal the details of these remarkable enhancements, we develop theoretical models to study the peeling processes. Based entirely on structural design, the proposed mechanism is non-material-specific and universally applicable to various intermolecular interactions under any harsh environment, such as high temperature, high humidity, and physiological environments. We envision that the strategy and methodologies presented can pave the avenue of future adhesion designs for both durability and reliability.

软材料在各个领域的应用通常需要界面粘合来承受长时间的静态或循环载荷，而大多数现有的粘合剂容易疲劳失效。与准静态脱粘过程不同，该过程更多地依赖于平均阻力，而防止疲劳裂纹扩展的关键是在局部建立高能量屏障。在此，我们采用三种类型的结构设计来诱导界面处的大能量障碍以实现抗疲劳粘附。通过改变衬底层的局部弯曲刚度，通过基利格米图案局部改变断裂模式，或通过简单的边缘缺口阻碍裂纹的起裂，我们将各种粘合剂抗剥落的疲劳阈值提高了几个数量级，达到了破纪录的值。为了验证所提出的机制并揭示这些显著增强的细节，我们开发了理论模型来研究剥离过程。该机制完全基于结构设计，非材料特异性，普遍适用于任何恶劣环境下的各种分子间相互作用，如高温、高湿和生理环境。我们设想，所提出的策略和方法可以为未来的耐久性和可靠性粘合设计铺平道路。

Bending Stiffness of Ionically Bonded Mica Multilayers told by its Bubbles

Baowen Li, Wang Tan, Chun Shen, Yuyang Long, Zhida Gao, Jiajun Wang, Wanlin Guo, Jun Yin

doi:10.1016/j.jmps.2024.105723

离子键合云母多层膜的弯曲刚度由其气泡决定

Revealing the bending stiffness of layered materials is crucial for guiding their applications with notable out-of-plane deformation, such as in flexible electronics. To this end, dedicated methods have been developed, but usually involving precise manipulation of atomically thin flakes or cross-section characterization with atomic resolution, hindering their widespread adoption. Here, we utilize mica as a case study to demonstrate that bubbles spontaneously formed during mechanical exfoliation provide a facile but reliable approach for investigating its bending mechanics. Through topographical analysis of bubbles with widely distributed sizes, a bending stiffness is extracted following a nonlinear plate theory. The less bending stiffness than the ideal non-linear plate solution indicates a moderate interlayer slip, as confirmed by molecular dynamics simulations. The interlayer shear coefficient for mica is higher than that for multilayer graphene, which is attributed to its strong interfacial shear strength inheriting from its interlayer ionic bonding.

揭示层状材料的弯曲刚度对于指导其在柔性电子等具有显着面外变形的应用至关重要。为此，已经开发了专门的方法，但通常涉及原子薄片的精确操作或原子分辨率的截面表征，阻碍了它们的广泛采用。在这里，我们以云母为例研究，证明在机械剥离过程中自发形成的气泡为研究其弯曲力学提供了一种简单而可靠的方法。通过对尺寸分布广泛的气泡进行形貌分析，根据非线性板理论提取了气泡的弯曲刚度。分子动力学模拟证实，与理想的非线性板溶液相比，弯曲刚度较小表明层间滑移适中。云母的层间剪切系数高于多层石墨烯，这是由于其层间离子键继承了较强的界面剪切强度。

International Journal of Plasticity

Tuning generalized planar fault energies to enable deformation twinning in nanocrystalline aluminum alloys

Jingfan Zhang, Xueyong Pang, Yue Li, Shaolou Wei, Chao Yang, Shuaihang Pan, Binhan Sun, Dengshan Zhou, Xiaoxu Huang, Deliang Zhang, Gaowu Qin

doi:10.1016/j.ijplas.2024.104018

调整广义平面断层能使纳米晶铝合金变形孪晶

As deformation twins have a profound impact on the plastic flow and mechanical properties of metallic materials, enhancing deformation twinning in face-centered cubic (FCC) metallic materials has long served as a unique microstructure design strategy to attain an extraordinary strength-ductility synergy. Deformation twinning, however, rarely occurs in pure FCC Al and its alloys since its generalized planar fault energies (GPFEs) are almost unaffected by most soluble alloying elements such as Mg, Zn and Cu. Here we successfully tune the GPFEs of a nanocrystalline Al-Mg alloy by alloying with Zr, Fe or Y element, and enable deformation twinning in the Zr-, Fe- and Y-containing alloys. Based on a combined analysis of microscopic observations, modeling and ab initio calculations, we find a strong grain-size-dependent twinning (i.e., twinning occurs in preferable grains having sizes in the range ∼20-40 nm), as well as only one single twinning plane (i.e., twinning occurs in single, parallel atomic planes) for twin formation rather than intersecting twinning planes (i.e., twinning occurs in multiple, unparallel atomic planes) usually observed in coarse-grained FCC materials. This interesting twinning behavior is further observed to be accompanied by grain rotations, producing defective twin boundaries. Our experimental results extend the current understanding of the plastic deformation mechanisms in nanograined metallic materials, and will guide microstructure design of twinnable nanograined Al alloys with an improved strength-ductility synergy.

变形孪晶对金属材料的塑性流动和力学性能有着深远的影响，增强面心立方(FCC)金属材料的变形孪晶一直是一种独特的微结构设计策略，以获得非凡的强度-塑性协同效应。变形孪晶在纯FCC Al及其合金中很少发生，因为其广义平面断层能(gpfe)几乎不受大多数可溶合金元素(Mg、Zn和Cu)的影响。在这里，我们成功地通过与Zr、Fe或Y元素合金化来调整纳米晶Al-Mg合金的GPFEs，并使含Zr、Fe和Y的合金发生变形孪晶。基于微观观察、建模和重新计算的综合分析，我们发现了一种强烈的晶粒尺寸依赖的孪晶(即，孪晶发生在尺寸在~ 20-40 nm范围内的优选晶粒中)，并且在粗粒FCC材料中通常观察到的孪晶形成只有一个单一的孪晶平面(即，孪晶发生在单个平行的原子平面中)，而不是相交的孪晶平面(即，孪晶发生在多个不平行的原子平面中)。这种有趣的孪晶行为进一步观察到伴随着晶粒旋转，产生缺陷孪晶边界。我们的实验结果扩展了目前对纳米金属材料塑性变形机制的理解，并将指导具有改进强度-塑性协同作用的可孪晶纳米铝合金的微观结构设计。

Thin-Walled Structures

Isogeometric material optimization for shape control of bi-directional functionally graded plates with piezoelectric layers

Liangliang Ma, Chao Wang, Yun Chong, Wenfeng Hu, Lei Zeng

doi:10.1016/j.tws.2024.112067

压电层双向功能梯度板形状控制的等几何材料优化

This paper proposes an effective numerical method for shape control of bi-directional functionally graded plates (2D-FGPs) with piezoelectric layers. Isogeometric analysis (IGA) based on non-uniform rational B-splines (NURBS) related to third-order shear deformation theory (TSDT) is employed for the static analysis of the 2D-FGPs with piezoelectric layers. The B-spline basis functions are utilized to represent the distribution of the ceramic volume fractions, where the control points placed along the plane corresponding to the ceramic volume fraction and the applied voltages are taken as the design variables. In addition, an improved moth flame optimization algorithm is utilized to solve the optimization problem of minimizing the static shape error, which effectively balances the exploratory and exploitative capabilities of the algorithm. Various numerical examples of square, skew, and dart-shaped 2D-FGPs are analyzed to validate the proposed method and demonstrated the superior mechanical performance of 2D-FGPs over 1D-FGPs.

提出了一种有效的具有压电层的双向功能梯度板形状控制的数值方法。采用基于非均匀有理b样条(NURBS)和三阶剪切变形理论(TSDT)的等几何分析(IGA)方法对具有压电层的二维fgps进行了静力分析。采用b样条基函数表示陶瓷体积分数的分布，其中以陶瓷体积分数所对应的平面控制点和外加电压为设计变量。此外，利用改进的蛾焰优化算法解决了静态形状误差最小化的优化问题，有效地平衡了算法的探索性和开发性。通过对方形、斜形和镖形2D-FGPs的数值分析，验证了该方法的有效性，并证明了2D-FGPs比1D-FGPs具有更好的力学性能。

Dynamic modeling and vibration suppression evaluation of composite honeycomb hemispherical shell with functional gradient protective coating

Hui Li, Jichuan Cao, Jintong Han, Jinghan Li, Yao Yang

doi:10.1016/j.tws.2024.112066

功能梯度防护涂层复合材料蜂窝半球形壳动力学建模及抑振评价

The vibration reduction performance of composite honeycomb hemispherical shells (CHHSs) coated with functional gradient protection coating (FGPC) are investigated in this work. Using the first-order shear deformation theory and the power-law distribution rule, the virtual spring technique, the regional decomposition method, and the Newmark-Beta approach, etc., a dynamic model of the FGPC-CHHSs under base excitation is formulated to solve the inherent characteristics and displacement responses in time and frequency domains. After a set of convergence analyses are completed to ascertain an appropriate segment number and the stiffness values of virtual springs employed in the predictive model, the forecasted vibration parameters are verified using the literature and experimental results that are performed on uncoated and coated shells. The maximal natural frequency errors of the current model compared to the experimental results are 3.8 % and 4.8 %, and the displacement response errors under different excitation amplitudes are less than 10.3 % and 12.7 %, respectively, which demonstrate the correctness of such a model. Finally, the impact of key structural and material parameters on the vibration behaviors of the FPGC-CHHSs is evaluated. To improve their vibration suppression capability, it is recommended to choose a high gradient index of coating material and a large thickness ratio of the FGPC to the overall shell with a reasonable moduli ratio of Material A to Material B of the FGPC to improve vibration reduction capability. This study offers a practical model tool and several important design recommendations for vibration prediction and dynamic attenuation of honeycomb sandwich hemispherical shell structures in aerospace engineering.

研究了涂覆功能梯度防护涂层(FGPC)的复合材料蜂窝半球形壳(chhs)的减振性能。利用一阶剪切变形理论和幂律分布规律、虚拟弹簧技术、区域分解法、Newmark-Beta方法等，建立了基础激励下fgpc - chhs的动力学模型，求解了其固有特性和时频域位移响应。在完成一组收敛分析以确定预测模型中使用的虚拟弹簧的适当段数和刚度值之后，使用文献和在未涂覆和涂覆壳体上进行的实验结果验证了预测的振动参数。与实验结果相比，当前模型的最大固有频率误差为3.8%和4.8%，不同激励幅值下的位移响应误差分别小于10.3%和12.7%，证明了该模型的正确性。最后，分析了关键结构参数和材料参数对fpga - chhs振动性能的影响。为了提高其减振能力，建议选择高梯度指数的涂层材料和大的FGPC与总壳的厚度比，以及合理的FGPC材料a与材料B的模量比，以提高其减振能力。该研究为航空航天工程中蜂窝夹层半球形壳结构的振动预测和动力衰减提供了实用的模型工具和一些重要的设计建议。

Design of thick-panel origami-inspired deployable protective shields for spacecraft

Xiaozhao Zhang, Chengjun Gao, Wujun Chen, Tianyang Yang, Shaochen Yang, Guangqiang Fang

doi:10.1016/j.tws.2024.112069

航天器厚板折纸式可展开防护罩设计

In recent years, as space is being explored more frequently, various spacecraft have been launched into space. Space debris and radiation in the universe as well as the irregular activities of the sun, such as solar flares and solar storms, can have serious effects on spacecraft. Protective shields are a favorable measure to protect spacecraft from space debris, radiation, and other damage. In this study, a protective shield for spacecraft is first proposed inspired by the behavior of mollusks. The concept of origami is then introduced for the folding and unfolding scheme design. The protective shield has a certain thickness, although its thickness is not significant and can be considered a thin-walled structure, it cannot be treated as zero-thickness origami since even a small thickness can cause issues such as motion interference. This study proposes three guidelines for thickening panels. Through the derivation of spatial geometry, a method to make the spatial curved surface thickening is presented. This method perfectly solves the compatibility problem of vertices in thickening, while making each panel manufacturable. After that, based on space vectors, a computational method for determining whether motion interference occurs in thick-panel curved origami is proposed, and the conditions for preventing motion interference are given. The accuracy and effectiveness of the proposed methods are verified by numerical simulations, and the complete unfolding and folding process of the deployable protective shield is also demonstrated. The methods proposed in this paper are all general and can be easily generalized to further and more complex situations. Finally, a case is shown where the deployable protective shield can be applied to a spacecraft like the Spitzer Space Telescope.

近年来，随着人们对太空的探索越来越频繁，各种航天器被发射到太空中。宇宙中的空间碎片和辐射以及太阳的不规则活动，如太阳耀斑和太阳风暴，都会对航天器产生严重影响。防护罩是保护航天器免受空间碎片、辐射和其他损害的有利措施。在这项研究中，受软体动物行为的启发，首次提出了航天器的防护盾。然后将折纸的概念引入到折叠和展开方案的设计中。保护罩有一定的厚度，虽然厚度不显著，可以认为是薄壁结构，但不能视为零厚度折纸，因为即使很小的厚度也会引起运动干扰等问题。这项研究提出了增厚面板的三条准则。通过空间几何的推导，提出了一种空间曲面增厚的方法。该方法很好地解决了加厚过程中顶点间的兼容性问题，同时又保证了每个面板的可制造性。在此基础上，提出了一种基于空间矢量判断厚板曲面折纸是否发生运动干涉的计算方法，并给出了防止运动干涉的条件。通过数值仿真验证了所提方法的准确性和有效性，并演示了可展开防护罩展开和折叠的完整过程。本文提出的方法都是通用的，可以很容易地推广到更复杂的情况。最后，给出了将可展开防护盾应用于斯皮策太空望远镜等航天器的实例。