【新文速递】2023年10月18日固体力学SCI期刊最新文章

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今日更新：Journal of the Mechanics and Physics of Solids 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 1 篇

Journal of the Mechanics and Physics of Solids

Buckling and lift-off of a heavy rod compressed into a cylinder

Shah R., van der Heijden G.H.M.

doi:10.1016/j.jmps.2023.105464

压缩成圆柱体的重棒的屈曲和腾空

We develop a comprehensive, geometrically-exact theory for an end-loaded heavy rod constrained to deform on a cylindrical surface. The cylinder can have arbitrary orientation relative to the direction of gravity. By viewing the rod-cylinder system as a special case of an elastic braid, we are able to obtain all forces and moments imparted by the deforming rod to the cylinder as well as all contact reactions. This framework allows for the monitoring of stresses to ascertain whether the cylinder, along with its end supports, is able to sustain the rod deformations. As an application of the theory we study buckling of the constrained rod under compressive and torsional loads, as well as the tendency of the rod to lift off the cylinder under further loading. The cases of a horizontal and vertical cylinder, with gravity having only a lateral or axial component, are amenable to exact analysis, while numerical results map out the transition in buckling mechanism between the two extremes. Weight has a stabilising effect for near-horizontal cylinders, while for near-vertical cylinders it introduces the possibility of buckling purely due to self-weight. Our results are relevant for many engineering and medical applications in which a slender structure is inserted into a cylindrical cavity.

我们为受限于在圆柱表面上变形的末端加载重杆建立了一个全面的、几何精确的理论。圆柱体相对于重力方向可以有任意方向。通过将杆-圆柱体系统视为弹性编织带的特例，我们能够获得变形杆传给圆柱体的所有力和力矩以及所有接触反作用力。在此框架下，我们可以对应力进行监测，以确定圆柱体及其端部支撑是否能够承受杆的变形。作为该理论的应用，我们研究了受约束杆在压缩和扭转载荷作用下的屈曲，以及杆在进一步载荷作用下脱离圆柱体的趋势。在重力只有横向或轴向分量的情况下，可以对水平和垂直圆柱体进行精确分析，而数值结果则描绘了两个极端之间的屈曲机制过渡。对于接近水平的圆柱体，重量具有稳定作用，而对于接近垂直的圆柱体，重量带来了纯粹由于自重而发生屈曲的可能性。我们的研究结果适用于将细长结构插入圆柱形空腔的许多工程和医疗应用。

International Journal of Plasticity

Inverse design of dual-phase steel microstructures using generative machine learning model and Bayesian optimization

Kusampudi N., Diehl M.

doi:10.1016/j.ijplas.2023.103776

利用生成式机器学习模型和贝叶斯优化法进行双相钢微结构逆向设计

The design of optimal microstructures requires first, the identification of microstructural features that influence the material’s properties and, then, a search for a combination of these features that give rise to desired properties. For microstructures with complex morphologies, where the number of features is large, deriving these structure–property relationships is a challenging task. To address this challenge, we propose a generative machine learning model that can automatically identify low-dimensional descriptors of microstructural features that can be used to establish structure–property relationships. Based on this model, we present an integrated, data-driven framework for microstructure characterization, reconstruction, and design that is applicable to heterogeneous materials with polycrystalline microstructures. The proposed method is evaluated on a case study of designing dual-phase steel microstructures created with the multi-level Voronoi tessellation method. To this end, we train a variational autoencoder to identify the descriptors from these synthetic dual-phase steel microstructures. Subsequently, we employ Bayesian optimization to search for the optimal combination of the descriptors and generate microstructures with specific yield stress and low susceptibility for damage initiation. The presented results show how microstructure descriptors, determined by the variational autoencoder model, act as design variables for an optimization algorithm that identifies microstructures with desired properties.

要设计出最佳的微结构，首先需要确定影响材料特性的微结构特征，然后寻找这些特征的组合，以获得所需的特性。对于形态复杂、特征数量众多的微结构来说，推导这些结构-性能关系是一项具有挑战性的任务。为了应对这一挑战，我们提出了一种生成式机器学习模型，该模型可以自动识别微结构特征的低维描述符，用于建立结构-性能关系。基于该模型，我们提出了一种用于微结构表征、重建和设计的数据驱动型集成框架，适用于具有多晶微结构的异质材料。我们在一个案例研究中对所提出的方法进行了评估，该案例研究使用多级 Voronoi 镶嵌法设计了双相钢微观结构。为此，我们训练了一个变异自动编码器来识别这些合成双相钢微结构的描述符。随后，我们采用贝叶斯优化法来寻找描述符的最佳组合，并生成具有特定屈服应力和低损伤起始敏感性的微结构。所展示的结果表明，由变异自动编码器模型确定的微观结构描述符可作为优化算法的设计变量，从而确定具有所需性能的微观结构。

Thin-Walled Structures

Performance of recycled aggregate concrete (RAC)-filled steel tubular (FST) members and K-joints under lateral impact

Lyu Wan-Qing, Han Lin-Hai, Hou Chao

doi:10.1016/j.tws.2023.111277

再生骨料混凝土（RAC）填充钢管（FST）构件和 K 型连接件在横向冲击下的性能

A series of tests are conducted on 26 recycle aggregate concrete (RAC)-filled steel tubular (FST) members and 25 RAC-FST K-joints on a drop hammer rig. Salient parameters considered in the experimental program include the axial load ratio, the replacement ratio of recycled coarse aggregate (RCA), the height of the hammer and the application of combined corrosion and sustained loading, et al. The shrinkage and creep deformation of core RAC is measured for 185 days, and the influence of key parameters on the structural performance of both RAC-FST members and K-joints are analyzed. A finite element (FE) model is established and verified against the test results. Considering the effects of combined chloride corrosion and sustained loading, the FE model is successively employed to investigate the behaviour of RAC-FST members and K-joints under lateral impact, including the failure mode, the time history relationships of impact load and deflection, the distribution of internal force and stress, et al. The axial compression performance of the member and the chords of K-joints after subjected to combined loading is evaluated. On the basis of the parametric analysis, simplified models considering the effects of chloride corrosion and sustained loading are obtained to calculate the dynamic flexural capacity of the RAC-FST members and the chords of RAC-FST K-joints under impact loads.

在落锤钻机上对 26 个循环骨料混凝土（RAC）填充钢管（FST）构件和 25 个 RAC-FST K 型连接件进行了一系列试验。实验程序中考虑的主要参数包括轴向荷载比、再生粗骨料（RCA）替代率、锤子高度以及腐蚀和持续加载的组合应用等，并测量了核心 RAC 185 天的收缩和徐变变形，分析了关键参数对 RAC-FST 构件和 K 型接头结构性能的影响。建立了有限元 (FE) 模型，并根据测试结果进行了验证。考虑到氯化物腐蚀和持续加载的综合影响，先后利用有限元模型研究了 RAC-FST 构件和 K 型连接件在横向冲击下的行为，包括破坏模式、冲击荷载和挠度的时间历史关系、内力和应力分布等。在参数分析的基础上，考虑到氯腐蚀和持续加载的影响，得到了简化模型，用于计算 RAC-FST 构件和 RAC-FST K 型连接件弦杆在冲击荷载下的动态抗弯能力。

来源：复合材料力学仿真Composites FEM

【新文速递】2023年10月4日固体力学SCI期刊最新文章

今日更新：Computer Methods in Applied Mechanics and Engineering 1 篇，Thin-Walled Structures 2 篇Computer Methods in Applied Mechanics and EngineeringA low-rank isogeometric solver based on Tucker tensorsMontardini M., Sangalli G., Tani M.doi:10.1016/j.cma.2023.116472基于塔克张量的低阶等距求解器We propose an isogeometric solver for Poisson problems that combines (i) low-rank tensor techniques to approximate the unknown solution and the system matrix, as a sum of a few terms having Kronecker product structure, (ii) a Truncated Preconditioned Conjugate Gradient solver to keep the rank of the iterates low, and (iii) a novel low-rank preconditioner, based on the Fast Diagonalization method where the eigenvector multiplication is approximated by the Fast Fourier Transform. Although the proposed strategy is written in arbitrary dimension, we focus on the three-dimensional case and adopt the Tucker format for low-rank tensor representation, which is well suited in low dimension. We show by numerical tests that this choice guarantees significant memory saving compared to the full tensor representation. We also extend and test the proposed strategy to linear elasticity problems.我们针对泊松问题提出了一种等几何求解器，该求解器结合了：(i) 低阶张量技术，将未知解和系统矩阵近似为具有克朗克积结构的几个项的总和；(ii) 截断预处理共轭梯度求解器，以保持较低的迭代秩；(iii) 基于快速对角化方法的新型低阶预处理器，其中特征向量乘法近似于快速傅立叶变换。虽然所提出的策略可以在任意维度下编写，但我们将重点放在三维情况下，并采用塔克格式来表示低秩张量，这种格式非常适合低维度。我们通过数值测试表明，与完整的张量表示法相比，这种选择能显著节省内存。我们还将提出的策略扩展到线性弹性问题并进行了测试。Thin-Walled StructuresA Unified Dynamic Model and Vibration Suppression for Moving Corrugated Sandwich Panels with General BoundariesZhou Kai, You Taiwen, Gong Dao, Zhou Jinsongdoi:10.1016/j.tws.2023.111248带一般边界的移动波纹夹芯板的统一动态模型与振动抑制The sandwich plate structures with corrugated cores are extensively utilized in engineering cases, such as the panels in railway vehicles, aerospace flight vehicles and so on. These sandwich plates in service can be simplified as the axially moving panel structures in the dynamic modeling. To research the dynamic behaviors of moving corrugated sandwich (CS) panels, an equivalent model is utilized. The energy method combined with penalty factor approach is applied to deduce the energy functions of the panel structure, and the corresponding formulations are further deduced based on the Hamilton's principle. Based on the proposed model, the examples with classical and elastic edge boundaries can be considered. Several computational examples are implemented to verify the present formulations, and satisfactory consistency can be observed. Meanwhile, impacts of several structural parameters on the dynamic and stability properties of the CS panel are investigated. To suppress the vibration of CS panels, the negative capacitance piezoelectric shunt damping circuit (PSDC) is further adopted. The impacts of the velocity parameter on the optimal values of the PSDC are discussed and calculated results demonstrate that dynamic responses of moving CS panels are satisfactorily attenuated by the proposed control strategy.带波纹芯材的夹层板结构在工程案例中得到广泛应用，如铁路车辆、航空飞行器等的面板。在动态建模中，这些服役中的夹芯板可简化为轴向移动的面板结构。为了研究移动波纹夹层板（CS）的动态行为，我们采用了等效模型。采用能量法结合惩罚因子法来推导板结构的能量函数，并根据汉密尔顿原理进一步推导出相应的公式。根据提出的模型，可以考虑经典和弹性边缘边界的示例。通过几个计算实例验证了本公式，并观察到了令人满意的一致性。同时，研究了几个结构参数对 CS 面板动态和稳定性能的影响。为了抑制 CS 面板的振动，进一步采用了负电容压电并联阻尼电路（PSDC）。讨论了速度参数对 PSDC 最佳值的影响，计算结果表明，采用所提出的控制策略后，移动 CS 面板的动态响应得到了令人满意的抑制。A star-shaped tubular structure with multiple-directional auxetic effectLang Jian Ping, Han Dong, Zhang Xue Gang, Jiang Wei, Zhang Yi, Ni Xi hai, Hao Jian, Teng Xing Chi, Ren Xindoi:10.1016/j.tws.2023.111247具有多向辅助效应的星形管状结构A majority of tubular structures have been widely studied due to their superior mechanical performance. Existing works on star-shaped tubular structures have focused on improving their stability and energy absorption performance. This paper proposes a novel star-shaped tubular lattice structure (STL), which not only possesses excellent mechanical properties but also exhibits exceptional auxetic effect. In addition, such structures exhibited two distinct deformation modes under different loading directions. Numerical and experimental studies of the mechanical behavior of the star-shaped tubular structure demonstrated low peak stresses under lateral loading and superior bearing capacity and stability under axial compression. Most importantly, the structure embodied a significant auxetic effect under the direction of both loads. The mechanical performance of the star-shaped tubular structures was investigated by changing wall thickness and angles, which can realize the optimal design. This study enriches the research on star-shaped tubular structures and provides a new perspective and reference for the design of auxetic tubular metamaterials in the future. Furthermore, the star-shaped tubular structure with auxetic behavior has considerable potential for applications in civil engineering and protective fields.大多数管状结构因其卓越的机械性能而被广泛研究。现有关于星形管状结构的研究主要集中在提高其稳定性和能量吸收性能上。本文提出了一种新型星形管状晶格结构（STL），这种结构不仅具有优异的机械性能，还表现出卓越的辅助效应。此外，这种结构在不同加载方向下表现出两种截然不同的变形模式。对星形管状结构力学行为的数值和实验研究表明，该结构在横向加载下具有较低的峰值应力，在轴向压缩下具有出色的承载能力和稳定性。最重要的是，该结构在两种载荷方向上都体现了显著的辅助效应。通过改变壁厚和角度，研究了星形管状结构的力学性能，从而实现了优化设计。这项研究丰富了星形管状结构的研究内容，为今后设计辅助管状超材料提供了新的视角和参考。此外，具有辅助行为的星形管状结构在土木工程和防护领域的应用具有相当大的潜力。来源：复合材料力学仿真Composites FEM