【新文速递】2024年11月26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 2 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 4 篇International Journal of Solids and StructuresBuckling analysis of PMMA hemispherical pressure shells with thickness variationLonghui Wang, Yongmei Zhu, Xilu Zhao, Jian Zhangdoi:10.1016/j.ijsolstr.2024.113109随厚度变化的PMMA半球形压力壳屈曲分析The buckling behaviour of polymethyl methacrylate (PMMA) hemispherical pressure shells under uniform external pressure was investigated experimentally and numerically. Six PMMA hemispherical pressure shells were prepared via the free blow-forming process. The geometry and wall thickness of each hemispherical shell were measured. The collapse loads and final failure modes of all shells were obtained via a hydrostatic pressure device. In addition, through optical 3D scanning, a numerical model of the hemispherical shell that reflects the actual geometric imperfection was established and used in the finite element buckling analysis. The numerical results were in agreement with the test results. These findings provide a reference for evaluating the buckling load of PMMA hemispherical shells prepared via the free blow-forming process.采用实验和数值方法研究了聚甲基丙烯酸甲酯（PMMA）半球形压力壳在均匀外压作用下的屈曲行为。采用自由吹塑工艺制备了6个PMMA半球形压力壳。测量了每个半球形壳体的几何形状和壁厚。通过静水压力装置获得了所有壳体的崩溃载荷和最终破坏模式。此外，通过光学三维扫描，建立了反映实际几何缺陷的半球形壳体的数值模型，并将其用于有限元屈曲分析。数值计算结果与试验结果吻合较好。研究结果可为自由吹塑法制备PMMA半球形壳的屈曲载荷评估提供参考。Journal of the Mechanics and Physics of SolidsInertia effect of deformation in amorphous solids: a dynamic mesoscale modelX.M. Duan, L. Yu, S.L. Cai, L.H. Dai, M.Q. Jiangdoi:10.1016/j.jmps.2024.105917非晶固体变形的惯性效应：一个动态中尺度模型Shear transformation (ST), as the fundamental event of plastic deformation of amorphous solids, is commonly considered as transient in time and thus assumed to be an equilibrium process without inertia. Such an approximation however poses a major challenge when the deformation becomes non-equilibrium, e.g., under the dynamic and even shock loadings. To overcome the challenge, this paper proposes a dynamic mesoscale model for amorphous solids that connects microscopically inertial STs with macroscopically elastoplastic deformation. By defining two dimensionless parameters: strain increment and intrinsic Deborah number, the model predicts a phase diagram for describing the inertia effect on deformation of amorphous solids. It is found that with increasing strain rate or decreasing ST activation time, the significant inertia effect facilitates the activation and interaction of STs, resulting in the earlier yield of plasticity and lower steady-state flow stress. We also observe that the externally-applied shock wave can directly drive the activation of STs far below the global yield and then propagation along the wave-front. These behaviors are very different from shear banding in the quasi-static treatment without considering the inertia effect of STs. The present study highlights the non-equilibrium nature of plastic events, and increases the understanding of dynamic or shock deformation of amorphous solids at mesoscale.剪切转变（ST）作为非晶固体塑性变形的基本事件，通常被认为在时间上是短暂的，因此被认为是一个没有惯性的平衡过程。然而，当变形变得非平衡时，例如，在动态和甚至冲击载荷下，这种近似提出了重大挑战。为了克服这一挑战，本文提出了一种非晶固体的动态中尺度模型，该模型将微观惯性STs与宏观弹塑性变形联系起来。该模型通过定义两个无量纲参数：应变增量和本征德博拉数，预测了描述惯性对非晶态固体变形影响的相图。研究发现，随着应变速率的增大或ST激活时间的缩短，显著的惯性效应有利于ST的激活和相互作用，使得塑性屈服提前，稳态流变应力降低。我们还观察到，外源激波可以直接驱动远低于总产率的STs激活，然后沿着波前传播。这些行为与未考虑STs惯性效应的准静态处理下的剪切条带有很大不同。本研究强调了塑性事件的非平衡性质，并增加了对中尺度非晶固体的动态或冲击变形的理解。Nonlinear soliton spiral induces coupled multimode dynamics in multi-stable dissipative metamaterialsWu Zhou, Yi-Ze Wangdoi:10.1016/j.jmps.2024.105920非线性孤子螺旋诱导多稳定耗散超材料的耦合多模动力学With the robust and self-trapped properties, recent advances about soliton dynamics in multi-stable mechanical metamaterials have led to many innovative techniques from signal processing to robotics. This work proposes a multi-stable mechanical metamaterial driven by nonlinear dissipative solitons, in which the coupling and decoupling of multiple locomotion modes can be achieved. Based on a cylinder network with asymmetric energy landscape, the uniform field model of Landau theory is developed. During the theoretical calculation, the analytical solutions of several dissipative solitons are derived, which allow multiple special behaviors of solitary waves, such as wave velocity gaps, directional propagation and spiral phase transition. By incorporating such effects into robotic designs, a variety of complex movements can be achieved by a single structure, including hopping, rolling, rotating, swinging, bending and translational components. In particular, as excitation positions change, the mechanical metamaterial can flexibly switch multiple locomotion modes without changing configurations, e.g., spinning and spin-less, straight and oblique as well as coupled multimode movements. This work wishes to provide some new inspirations for the applications of nonlinear elastic wave metamaterials and phase transition theory in robotics.随着多稳定机械超材料中孤子动力学的鲁棒性和自困性的研究进展，导致了从信号处理到机器人技术的许多创新技术。本文提出了一种由非线性耗散孤子驱动的多稳定机械超材料，该材料可以实现多种运动模式的耦合和解耦。基于具有非对称能量景观的圆柱网络，建立了朗道理论的均匀场模型。在理论计算过程中，导出了几种耗散孤子的解析解，这些解析解允许孤波具有波速间隙、定向传播和螺旋相变等多种特殊行为。通过将这些效果纳入机器人设计，各种复杂的运动可以通过一个单一的结构来实现，包括跳跃，滚动，旋转，摆动，弯曲和平移组件。特别是，随着激励位置的变化，机械超材料可以在不改变构型的情况下灵活切换多种运动模式，如自旋和不自旋、直线和斜向以及耦合多模运动。希望为非线性弹性波超材料和相变理论在机器人技术中的应用提供一些新的启示。Mechanics of MaterialsExperimental and Theoretical Investigation of Chronic Lymphocytic Leukemia Cell’s Viscoelastic Contact Mechanics Using Atomic Force MicroscopeMoharram Habibnejad Korayem, Mahboube Mehrabanidoi:10.1016/j.mechmat.2024.105186原子力显微镜下慢性淋巴细胞白血病细胞粘弹性接触力学的实验与理论研究Chronic Lymphocytic Leukemia (CLL) is a type of cancer usually appearing in old age. In this research, a method for detecting CLL cells in young age through the analysis of geometrical and mechanical properties of human Leukocytes has been presented. For this purpose, the CLL cells are cultured and their geometric characteristics, adhesion force, and contact behavior have been examined using an Atomic Force Microscope (AFM) device. Subsequently, the obtained experimental results have been compared with the geometric and mechanical properties of Leukocytes. Furthermore, the manipulation process has been mathematically modeled using different adhesive and non-adhesive contact theories. The results showed that blood cancer cells have up to 8.17% smaller dimensions and up to 23.57% greater elastic modulus compared to leukocytes.慢性淋巴细胞白血病（CLL）是一种常见于老年的癌症。在这项研究中，通过分析人类白细胞的几何和力学特性，提出了一种检测年轻时CLL细胞的方法。为此，培养CLL细胞，并使用原子力显微镜（AFM）设备检查其几何特征、粘附力和接触行为。随后，将得到的实验结果与白细胞的几何和力学特性进行了比较。此外，采用不同的粘接和非粘接接触理论对操作过程进行了数学建模。结果表明，与白细胞相比，血癌细胞的尺寸缩小了8.17%，弹性模量增加了23.57%。Thin-Walled StructuresA four-node inverse curved shell element coupling MITC method for deformation reconstruction of plate and shell structuresXiao Xiao, Shishun Zhang, Jianping Xuan, Tielin Shidoi:10.1016/j.tws.2024.112598板壳结构变形重建的四节点逆弯曲壳元耦合MITC方法In the field of structural deformation monitoring, the inverse finite element method (iFEM) has significant engineering value as a structural health monitoring technique that provides timely and reliable warnings for shell structures. However, existing inverse finite elements are mainly based on first-order shear deformation theory and kirchhoff-love theory, which are not suitable for deformation reconstruction in plate and shell structures of arbitrary thickness. This study integrates iFEM with the Mixed Interpolation of Tensorial Components (MITC) method to develop a novel four-node quadrilateral inverse curved shell element, named iMICS(inverse Mixed Interpolation Curved Shell)4, aimed at enhancing the accuracy and efficiency of deformation reconstruction in complex plate and shell structures. The method uses the MITC4 shell element as the kinematic framework and applies the least squares variational principle to achieve deformation reconstruction, effectively alleviating shear and membrane locking issues across structures of varying thickness. Numerical examples validate the superior performance of the iMICS4 element, demonstrating its promising application prospects.在结构变形监测领域，逆有限元法作为一种为壳结构提供及时、可靠预警的结构健康监测技术，具有重要的工程价值。然而，现有的逆有限元主要基于一阶剪切变形理论和kirchhoff-love理论，不适用于任意厚度板壳结构的变形重建。为了提高复杂板壳结构变形重建的精度和效率，本研究将iFEM与张量分量混合插值（MITC）方法相结合，开发了一种新型的四节点四边形逆弯曲壳单元iMICS(inverse Mixed Interpolation curved shell)4。该方法以MITC4壳单元为运动框架，应用最小二乘变分原理实现变形重构，有效缓解变厚度结构间的剪切和锁膜问题。数值算例验证了iMICS4元件的优越性能，展示了其广阔的应用前景。Kinematics and dynamics characteristics of a double-ring truss deployable antenna mechanism based on triangular prism deployable unitBo Han, Yuanzhi Zhou, Meng Han, Xiaoyu Hu, Yundou Xu, Jiantao Yaodoi:10.1016/j.tws.2024.112608 基于三棱柱展开单元的双环桁架可展开天线机构的运动学与动力学特性In order to effectively improve the single-ring truss deployable antenna mechanism due to the large aperture caused by the problem with low structural strength and low-profile accuracy, a series of double-ring truss deployable antenna mechanisms (DRTDAM) are proposed with constant height during folding and deployment process. First, a variety of DRTDAMs are proposed based on tetrahedral units and their topologies are analyzed. Secondly, degree-of-freedom (DOF) characteristics of DRTDAM proposed in this paper are analyzed based on the screw theory and screw-constrained topological graphs and based on this, the kinematic characteristics of DRTDAM is investigated. Thirdly, the dynamics of the whole DRTDAM is built with Newton-Euler equations of multi-rigid body system. Finally, the correctness of above analysis is verified through dynamics analysis software ADAMS and numerical analysis software MATLAB, and the principle prototype is produced to verify the correctness of DOF analysis. The mechanism proposed in this paper enriches the configuration of DRTDAM, and the process of kinematic characterization method is clear and simple, which is meaningful for the research in space complex mechanism.为有效改善单环桁架可展开天线机构因孔径大而造成的结构强度低、外形精度低等问题，提出了一系列在折叠和展开过程中保持恒定高度的双环桁架可展开天线机构（DRTDAM）。首先，提出了基于四面体单元的多种drtdam，并对其拓扑结构进行了分析。其次，基于螺旋理论和螺旋约束拓扑图分析了本文提出的DRTDAM的自由度特性，并在此基础上对DRTDAM的运动特性进行了研究。第三，利用多刚体系统的牛顿-欧拉方程建立了整个DRTDAM的动力学模型。最后，通过动力学分析软件ADAMS和数值分析软件MATLAB验证了上述分析的正确性，并制作了原理样机，验证了自由度分析的正确性。本文提出的机构丰富了DRTDAM的构型，且运动学表征方法过程清晰简单，对空间复杂机构的研究具有重要意义。Boosting tree with bootstrap technique for pre-stress design in cable dome structuresYutao He, Jiamin Guo, Huan Ping, MingLiang Zhu, Weigang Chen, Guangen Zhoudoi:10.1016/j.tws.2024.112611基于自举技术的索穹顶结构预应力设计助推树Tensegrity structures, known for their rigidity derived from feasible pre-stresses, present unique challenges in structural engineering. Traditional force-finding methods, though comprehensive, rely heavily on intricate matrix computations, making them computationally intensive and often uncomfortable for considering external loads in practical engineering scenarios. This paper introduces a novel approach to compute pre-stresses in cable dome structures by integrating machine learning and probability theory, collectively termed the boosting tree with bootstrap technique (BTWBT). This method reduces the sample size to as few as 100 per iteration, while improving computational efficiency by randomly generating internal forces. By reframing the force determination as an inverse problem, it ensures that structural displacement converges to zero under feasible pre-stresses. The effectiveness of BTWBT is demonstrated across three distinct cable dome structures: the Geiger dome, Kiewitt dome, and rotating hyperboloid cable dome. Results show that BTWBT achieves the preset displacement requirement (maximum nodal displacement below 0.01 mm) with fewer iterations and reduced computational cost compared to traditional machine learning methods. BTWBT's capability to manage complex structural configurations with minimal data, while incorporating random internal force generation ranges, highlights its potential as a superior alternative for force determination in tensegrity structures.张拉整体结构以其刚度来源于可行的预应力而闻名，在结构工程中提出了独特的挑战。传统的力查找方法虽然全面，但严重依赖于复杂的矩阵计算，使其计算量大，并且在实际工程场景中考虑外部载荷时往往不舒服。本文介绍了一种结合机器学习和概率论计算索穹顶结构预应力的新方法，统称为带bootstrap的提升树技术（BTWBT）。该方法将每次迭代的样本量减少到100个，同时通过随机生成内力来提高计算效率。通过将力的确定重构为一个逆问题，保证了在可行的预应力下结构位移收敛于零。BTWBT的有效性通过三种不同的电缆圆顶结构得到证明：盖格圆顶、基维特圆顶和旋转双曲面电缆圆顶。结果表明，与传统的机器学习方法相比，BTWBT以更少的迭代次数和更低的计算成本达到了预设的位移要求（最大节点位移小于0.01 mm）。BTWBT能够以最少的数据管理复杂的结构配置，同时结合随机内力产生范围，突出了其作为张拉整体结构中力确定的优越替代方案的潜力。Nonlinear Finite Element Formulation for Thin-Walled Conical ShellsSaher Attia, Magdi Mohareb, Samer Adeebdoi:10.1016/j.tws.2024.112617薄壁锥形壳的非线性有限元公式This study presents a novel finite element formulation to predict the geometrically nonlinear response of conical shells under a wide range of practical loading conditions. The formulation expresses the discretized equilibrium equations in terms of the first Piola-Kirchhoff stress tensor and its conjugate gradient of the virtual displacements, is based on the kinematics of Love-Kirchhoff thin shell theory and the Saint-Venant-Kirchhoff constitutive model, and captures the follower effect of pressure loading. The formulation takes advantage of the axisymmetric nature of the shell geometries by adopting a Fourier series to characterize the displacement distributions along the circumferential direction while using Hermitian interpolation along the meridional direction. Comparisons with general shell models show the accuracy of the formulation under various loading conditions with a minimal number of degrees of freedom, resulting in a significant computational efficiency compared to conventional general-purpose shell solutions.本文提出了一种新的有限元公式来预测锥形壳在各种实际载荷条件下的几何非线性响应。该公式基于Love-Kirchhoff薄壳理论的运动学和Saint-Venant-Kirchhoff本构模型，以第一Piola-Kirchhoff应力张量及其虚位移共轭梯度表示离散平衡方程，并捕捉了压力加载的跟随效应。该公式利用了壳体几何形状的轴对称特性，采用傅里叶级数来表征沿周向的位移分布，而沿子午方向使用厄米插值。与一般壳模型的比较表明，该公式在各种载荷条件下具有最小自由度的准确性，与传统的通用壳解相比，计算效率显著提高。来源：复合材料力学仿真Composites FEM