【新文速递】2023年10月22日固体力学SCI期刊最新文章

今日更新：Mechanics of Materials 1 篇，Thin-Walled Structures 5 篇

Mechanics of Materials

Generative design and mechanical properties of the lattice structures for tensile and compressive loading conditions fabricated by selective laser melting

Han Tian, Qi Dandan, Ma Jia, Sun Chaoyang

doi:10.1016/j.mechmat.2023.104840

选择性激光熔融法制造的拉伸和压缩加载条件下晶格结构的生成设计和力学性能

In this study, the generative design method was adopted to propose new modified lattice structures, which are suitable for tensile and compressive loading conditions. The effects of constraint stress and load magnitude on the lattice structure were analyzed. The inclined beams of body-centered cubic (BCC) were replaced with two parallel or crossed struts to improve the lattices' manufacture ability, obtaining three levels of self-supporting derived structures. Samples of AlSi10Mg material were successfully fabricated by selective laser melting (SLM) technology and the surface morphology was observed under the scanning electron microscope (SEM). The mechanical properties and energy absorption capability of the lattices were investigated by quasi-static compressive testing. Finite element (FE) models were also developed, which were in good accordance with the experiment results. Results indicated that the derived structures perform better load-bearing capacity and energy absorption compared with the original body-centered cubic without (BCC) and with z-struts (BCCZ), and the parallel body-centered cubic with horizontal struts and z-struts (P-BCCXYZ) shows the best. In addition, the effects of shape parameters on elastic modulus and yield strength were also discussed. The proposed lattices are expected to be widely used for components subjected to tensile and compressive loads, such as supporting, guarding, and connecting parts.

本研究采用了生成设计法，提出了适用于拉伸和压缩荷载条件的新型改良格构。分析了约束应力和荷载大小对格子结构的影响。将体心立方体（BCC）的斜梁替换为两个平行或交叉的支柱，以提高晶格的制造能力，从而获得了三个层次的自支撑衍生结构。利用选择性激光熔融（SLM）技术成功制备了 AlSi10Mg 材料样品，并在扫描电子显微镜（SEM）下观察了其表面形貌。通过准静态压缩试验研究了晶格的机械性能和能量吸收能力。此外，还建立了有限元（FE）模型，这些模型与实验结果十分吻合。结果表明，推导出的结构与原始的不带（BCC）和带 z 支杆（BCCZ）的体心立方体相比，具有更好的承载能力和能量吸收能力，而带水平支杆和 z 支杆的平行体心立方体（P-BCCXYZ）的承载能力和能量吸收能力最佳。此外，还讨论了形状参数对弹性模量和屈服强度的影响。所提出的晶格有望广泛用于承受拉伸和压缩载荷的部件，如支撑、防护和连接部件。

Thin-Walled Structures

Mixed MITC and interface shell element formulation for multi-part viscoelastic shell structures

Nguyen Sy-Ngoc, Ho Thuan N.-T., Ly Duy-Khuong, Han Jang-Woo, Lee Jaehun

doi:10.1016/j.tws.2023.111283

多部分粘弹性壳体结构的混合 MITC 和界面壳体元素配方

This study presents a novel approach for constitutive modeling of multi-part viscoelastic shell structures using a combination formulation of mixed MITC (MITC3 and MITC4) and interface shell elements with reduced computational cost. It focuses on accurate viscoelastic analysis, considering the time-dependent behavior of the multi-part shell structures. The use of the Laplace transform simplifies the integral-form constitutive equation, enabling efficient and accurate viscoelastic analysis. Moreover, by combining the advantages of MITC shell elements and interface shell elements, this approach comprehensively represents multi-part shell structures with non-matching interfaces. Hence, it allows the meshing of each component part independently when assembled. Furthermore, these methods also provide better resistance to shear and membrane locking, which can be problematic when modeling thin shell structures. In numerical examples, to validate the accuracy of the current study, we meticulously analyze multi-part shell models such as an elastic U-shaped beam and the viscoelastic propeller subjected to creep bending loads. This research contributes to improving the design and performance of shell structures in various engineering fields.

本研究采用混合 MITC（MITC3 和 MITC4）和界面壳元素的组合公式，提出了一种新的多部分粘弹性壳结构的构成建模方法，并降低了计算成本。它侧重于精确的粘弹性分析，并考虑了多部分壳体结构的时变行为。拉普拉斯变换的使用简化了积分形式的构成方程，从而实现了高效、精确的粘弹性分析。此外，通过结合 MITC 壳元素和界面壳元素的优势，该方法全面地表示了具有非匹配界面的多部分壳结构。因此，它允许在组装时对每个部件进行独立网格划分。此外，这些方法还能更好地抵抗剪切和膜锁定，而这在薄壳结构建模时可能会出现问题。为了验证当前研究的准确性，我们在数值示例中对弹性 U 形梁和承受蠕变弯曲载荷的粘弹性螺旋桨等多部分壳体模型进行了细致分析。这项研究有助于改善各种工程领域中壳结构的设计和性能。

Crushing behavior of multi-layer lattice-web reinforced double-braced composite cylinders under lateral compression and impact loading

Chen Jiye, Fang Hai, Zhuang Yong, Shen Zhongxiang, He Wangwang

doi:10.1016/j.tws.2023.111289

横向压缩和冲击载荷下多层格网加固双支撑复合材料圆柱体的破碎行为

This paper reports on the crushing behavior of several novel multi-layer lattice-web reinforced double-braced composite cylinders composed of glass fiber reinforced polymer (GFRP) face sheets, GFRP lattice webs, polyurethane (PU) foam core and steel bars. A series of quasi-static lateral compression and low-velocity impact experiments were carried out to investigate the feasibility of the proposed cylinders. All the experimental specimens were manufactured using a vacuum assisted resin infusion process (VARIP) method. The bearing capacity and energy absorption performance of the composite cylinders can be significantly improved with the enhancement of multi-layer lattice-web layout and use of bracing. Among the proposed three types of lattice-web layouts, the double-layer dislocated lattice-web layout made the composite cylinder exhibit the greatest specific energy absorption (SEA) performance and good impact resistance property and can be chosen as an optimal configuration. Furthermore, numerical models were established using LS-‍DYNA software to simulate the large deformation of the composite cylinders with double-layer dislocated lattice-web layout. Based on the numerical models, parametric analysis was carried out to discuss the effects of various parameters on the crushing behavior of the composite cylinders. The bearing capacity and impact resistance property can be generally improved with the increase of GFRP thickness or radial lattice-web height. Additionally, using stronger foam material or smaller inclination of bracing can increase the absorbed energy in PU foam but the GFRP material always makes an essential contribution to the energy absorption of the composite cylinders.

本文报告了由玻璃纤维增强聚合物（GFRP）面片、GFRP 格状网、聚氨酯（PU）泡沫芯材和钢筋组成的几种新型多层格状网增强双支撑复合材料圆柱体的挤压行为。为了研究拟议圆柱体的可行性，我们进行了一系列准静态横向压缩和低速冲击实验。所有实验试样均采用真空辅助树脂灌注工艺（VARIP）制造。通过加强多层格网布局和使用支撑，复合材料圆柱体的承载能力和能量吸收性能得到了显著提高。在所提出的三种晶格网布局中，双层错位晶格网布局使复合材料圆柱体具有最大的比能量吸收（SEA）性能和良好的抗冲击性能，可作为最佳配置。此外，还利用 LS-‍DYNA 软件建立了数值模型，模拟了双层错位格网布局复合材料圆柱体的大变形。在数值模型的基础上，进行了参数分析，讨论了各种参数对复合材料圆柱体破碎行为的影响。随着 GFRP 厚度或径向格网高度的增加，承载能力和抗冲击性能普遍得到改善。此外，使用强度更高的泡沫材料或较小的支撑倾斜度也能增加聚氨酯泡沫的能量吸收，但 GFRP 材料始终对复合材料圆柱体的能量吸收起着至关重要的作用。

The harmonic resonance and singularity analysis of bifurcation for the magnetized elastic plate with action of time-varying magnetic potential

Hu Yuda, Tian Yuxin, Xie Mengxue

doi:10.1016/j.tws.2023.111290

磁化弹性板在时变磁势作用下的谐波共振和分岔奇异性分析

This paper deals with the superharmonic resonance of a ferromagnetic thin rectangular plate in the air-gap magnetic field excited by armature magnetic potential. Electromagnetic forces applied on the plate by the air-gap magnetic field cause the plate to transversal vibrate, which affects the air-gap magnetic field in turn, resulting the vibration and magnetic field coupling. According to the basic electromagnetic field theory and considering the magnetoelastic coupling effect, the air-gap magnetic field intensity is obtained by solving the Laplace's equation satisfied the air-gap magnetic boundary conditions. The electromagnetic force model of soft ferromagnetic plates is determined based on theories of electromagnetic and elasticity. According to the large deflection theory of plates, basic energy relationships and variational equations of the elastic plate are given. Eventually, the nonlinear magnetoelastic vibration equation of ferromagnetic thin plates is derived using Hamilton's principle and Galerkin method. The multi-scale method is used to solve the superharmonic resonance to obtain the amplitude-frequency response equation and the stability discriminant of solutions. The topological analysis of amplitude-frequency equation is carried out using singularity theory, and the bifurcation characteristics of systems on physical parameter planes in different regions are obtained according to the transition set. The correctness of analytical solutions is verified by comparison with numerical solutions. Through numerical calculations, curves of the static deflection and equivalent magnetic force of plate with parameters are given, and the amplitude curves, dynamic phase plane trajectories and time history diagrams of system response with changes in electromagnetic and structural parameters are plotted. Results show that both the decrease of armature magnetic potential amplitude and the increases of plate thickness and initial air-gap thickness reduce the static deflection. The increase of armature magnetic potential amplitude increases the equivalent magnetic force. As the decrease of initial air-gap thickness and the increases of armature magnetic potential amplitude and excitation force amplitude, the amplitudes of the upper branch and lower branch curves representing stable solutions decrease and increase, respectively, and the single-value solution region increases.

本文论述了铁磁性薄矩形板在电枢磁势激励的气隙磁场中的超谐波共振。气隙磁场施加在薄板上的电磁力引起薄板横向振动，进而影响气隙磁场，导致振动与磁场耦合。根据基本电磁场理论并考虑磁弹性耦合效应，通过求解满足气隙磁边界条件的拉普拉斯方程，得到气隙磁场强度。根据电磁理论和弹性理论确定了软铁磁板的电磁力模型。根据板的大挠度理论，给出了弹性板的基本能量关系和变分方程。最后，利用汉密尔顿原理和 Galerkin 方法推导出铁磁性薄板的非线性磁弹性振动方程。利用多尺度方法求解超谐波共振，得到幅频响应方程和解的稳定性判别式。利用奇异性理论对幅频方程进行拓扑分析，根据过渡集得到不同区域物理参数平面上系统的分岔特征。通过与数值解的对比，验证了解析解的正确性。通过数值计算，给出了板的静态挠度和等效磁力随参数变化的曲线，并绘制了系统响应随电磁参数和结构参数变化的振幅曲线、动态相位平面轨迹和时间历程图。结果表明，电枢磁势幅值减小、板厚和初始气隙厚度增加都会减小静态挠度。电枢磁势幅值的增加会提高等效磁力。随着初始气隙厚度的减小以及电枢磁势幅值和激振力幅值的增大，代表稳定解的上分支和下分支曲线的幅值分别减小和增大，单值解区域增大。

The Influence of Inelastic Materials on Freeform Kerf Structures

Darnal Aryabhat, Mantri Kanak, Shahid Zaryab, Kalantar Negar, Muliana Anastasia

doi:10.1016/j.tws.2023.111292

非弹性材料对自由形态切口结构的影响

Kerfing or relief cutting is a fabrication approach to create moldable surfaces out of wood and metal panels. The kerf panels with pre-defined microstructural topology enable the creation of freeform kerf structures of complex geometries, which found many applications in building constructions. This study investigates the influence of inelastic materials, i.e., plastic deformation of stainless steel and viscoelastic wood, and microstructural topology on the overall moldability of kerf panels. Kerf unit cells fabricated from stainless steel (SS) and medium-density fiber (MDF) with different cut patterns, cut densities, and cell sizes are first studied. Experimental tests and mathematical models are used to examine the deformations of the kerf unit cells. Kerf panels of various microstructural topology, which depends on the cut patterns, cut densities, cell sizes, and cell arrangements, are then modeled to create freeform shapes. The effect of inelastic deformations, i.e., shape reconfiguration due to creep of MDF and utilizing inelastic deformations of SS to form the freeform shapes, are studied. When only an elastic deformation is considered, increasing the flexibility in kerf panels by increasing cut densities enables easy shape configurations. However, when a plastic deformation is utilized to form the shape, flexible kerf structures are less effective due to the relatively small stresses in the flexible kerf structures. Flexible kerf structures can experience significant creep deformations, inducing nonnegligible shape reconfigurations. To avoid shape reconfigurations due to the creep effect when using viscoelastic wood, one approach is to consider developable surfaces.

切口或浮雕切割是一种在木板和金属板上制造可成型表面的制造方法。具有预定义微结构拓扑的切口板能够创建复杂几何形状的自由形态切口结构，在建筑施工中得到广泛应用。本研究探讨了非弹性材料（即不锈钢和粘弹性木材的塑性变形）和微结构拓扑对切口板整体成型性的影响。首先研究了由不锈钢（SS）和中密度纤维（MDF）制成的具有不同切割模式、切割密度和单元尺寸的切口单元。实验测试和数学模型用于研究切口单元的变形。然后，根据切割模式、切割密度、单元尺寸和单元排列，对不同微结构拓扑的切口面板进行建模，以创建自由形状。研究了非弹性变形的影响，即中密度纤维板蠕变导致的形状重构，以及利用 SS 的非弹性变形形成自由形状。在只考虑弹性变形的情况下，通过增加切割密度来提高切口面板的柔韧性，可以轻松实现形状配置。然而，当利用塑性变形形成形状时，由于柔性切口结构中的应力相对较小，柔性切口结构的效果较差。柔性切口结构可能会发生显著的蠕变变形，从而导致不可忽略的形状重构。在使用粘弹性木材时，为避免蠕变效应导致的形状重构，一种方法是考虑可展开表面。

Discrete Ritz method for buckling analysis of arbitrarily shaped plates with arbitrary cutouts

Jing Zhao, Duan Lei

doi:10.1016/j.tws.2023.111294

用离散里兹法分析带有任意切口的任意形状板材的屈曲问题

To overcome the difficulties of the Ritz method when dealing with complex geometric domain problem, a novel general numerical approach, discrete Ritz method (DRM), is proposed for buckling analysis of arbitrarily shaped plates with arbitrary cutouts. Accounting for a variety of boundary conditions, Legendre polynomials are adopted to construct the admissible function. By using the global trial function with variable stiffness properties within a virtual rectangular design domain, the deformation of any shape perforated plates can be captured with the help of numerical integration using Gauss quadrature. The shapes and cutouts of plates are both numerically simulated by using cutouts, where the stiffness is assigned zero within the cutouts in the virtual rectangular domain. Moreover, boundary conditions and load potential can be applied to any contour of the plate. Based on the above formulation, standard energy functionals and computation procedures are established to extract the buckling eigenvalues and mode shapes. Various shape plates with arbitrarily shaped cutouts are investigated. Under several boundary conditions, multiple inplane loads are applied, and the results are compared with those obtained by other numerical and analytical methods in the literature. Demonstrating the stability and accuracy of the DRM.

为了克服里兹法在处理复杂几何域问题时的困难，我们提出了一种新颖的通用数值方法--离散里兹法（DRM），用于带有任意切口的任意形状板材的屈曲分析。考虑到各种边界条件，该方法采用 Legendre 多项式来构建容许函数。通过在虚拟矩形设计域内使用具有可变刚度属性的全局试验函数，可以利用高斯二次方程进行数值积分，从而捕捉任意形状穿孔板的变形。板的形状和切口均可通过切口进行数值模拟，在虚拟矩形域中，切口内的刚度为零。此外，边界条件和负载势能可应用于板的任何轮廓。根据上述公式，建立了标准能量函数和计算程序，以提取屈曲特征值和模态振型。研究了带有任意形状切口的各种形状板。在几种边界条件下，施加了多个平面载荷，并将结果与文献中其他数值和分析方法得出的结果进行了比较。证明了 DRM 的稳定性和准确性。