【新文速递】2024年7月16日固体力学SCI期刊最新文章

 

今日更新：International Journal of Solids and Structures 4 篇，Journal of the Mechanics and Physics of Solids 2 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 7 篇

International Journal of Solids and Structures

The effect of dislocation pile-up on microcrack initiation in microcrystalline materials in the hydrogen environment

Jiding Zhang, Xiaoyu Jiang, Yundie Zhu, Xu Zhang, Keke Zhao

doi:10.1016/j.ijsolstr.2024.112972

氢环境下位错堆积对微晶材料微裂纹萌生的影响

In this paper, hydrogen (H) induced microcrack initiation in the first stage of crack propagation is studied. Based on the knowledge of fracture mechanics and discrete distributed dislocation method, the interaction model between hydrogen atoms at crack tip and dislocation source, the grain boundary (GB) penetration model and microcrack initiation criterion are established, and the microcrack initiation mechanism caused by dislocation pile-up near the grain boundary 2 (GB2) is studied. Meanwhile, the mechanism of dislocation synthesis (DS) caused by dislocation stacking is studied. The results show that hydrogen atoms promote the emission of dislocations at the crack tip. The distribution of H atoms at the crack tip (CT) leads to an increase in the number of dislocations penetrating the grain boundary, and the number of dislocation pile-up in the second phase grain increases. In the hydrogen environment, the number of dislocation pile-up near GB2 increases, resulting in a large stress concentration near GB2, which makes microcracks more likely to occur. At the same time, H can decrease the surface energy of materials, making materials more prone to brittle fracture. The study of hydrogen induced crack initiation is helpful to understand and control the impact of H on the performance and reliability of metal materials, which plays a crucial role in improving the working efficiency and service life of metal materials.

本文研究了裂纹扩展第一阶段氢诱导的微裂纹萌生。基于断裂力学知识和离散分布位错方法，建立了裂纹尖端氢原子与位错源的相互作用模型、晶界(GB)侵穿模型和微裂纹起裂判据，研究了晶界2 (GB2)附近位错堆积引起的微裂纹起裂机理。同时，研究了位错叠加引起的位错合成(DS)的机理。结果表明，氢原子促进了裂纹尖端位错的产生。裂纹尖端H原子的分布导致穿透晶界的位错数量增加，第二相晶粒中的位错堆积数量增加。在氢气环境下，GB2附近位错堆积数量增加，导致GB2附近应力集中较大，更容易发生微裂纹。同时，H能降低材料的表面能，使材料更容易发生脆性断裂。氢致裂纹起裂的研究有助于理解和控制氢对金属材料性能和可靠性的影响，对提高金属材料的工作效率和使用寿命具有至关重要的作用。

Residual closure of fatigue cracks

James Vidler, Andrei Kotousov, Ching-Tai Ng

doi:10.1016/j.ijsolstr.2024.112973

疲劳裂纹的残余闭合

The plasticity-induced crack closure phenomenon has been the subject of many previous theoretical and experimental studies. From these studies it was found that in the absence of applied loading, a fatigue crack is likely to be partially closed due to the plastic wake, which is generated behind the tip of a propagating crack. This partial, or residual, closure has many implications for theoretical modelling as well as practical applications. However, no theoretical models have been developed to evaluate what part of a propagating fatigue crack is closed in the free from stress state. Direct 3D FE simulations of the plasticity-induced crack closure are very challenging, time consuming, and are not feasible for a large number of fatigue cycles. Therefore, the current paper utilises a 2D strip-yield idealisation and the distributed dislocation technique to investigate the effects of the stress amplitude and R-ratio of fatigue loading on the residual crack closure. The outcomes of this work may assist in the evaluation of the adequacy and limitations of the current analytical and computational models describing the behaviour of structures containing fatigue cracks, as well as in the interpretation of data from nondestructive defect inspections.

塑性裂纹闭合现象一直是许多理论和实验研究的主题。从这些研究中发现，在没有施加载荷的情况下，疲劳裂纹可能由于塑性尾迹而部分关闭，塑性尾迹在扩展裂纹尖端后面产生。这种部分或剩余的封闭性对理论建模和实际应用都有许多影响。然而，目前还没有理论模型来评估在无应力状态下扩展疲劳裂纹的哪个部分是闭合的。直接进行塑性裂纹闭合的三维有限元模拟是非常具有挑战性的，耗时的，并且不适用于大量的疲劳循环。因此，本文利用二维条形屈服理想化和分布位错技术来研究疲劳载荷的应力幅值和r比对残余裂纹闭合的影响。这项工作的结果可能有助于评估当前描述包含疲劳裂纹的结构行为的分析和计算模型的充分性和局限性，以及对无损缺陷检查数据的解释。

Multiscale periodic homogenization for additive manufacturing of honeycomb lattices

Valentin Marchal, Tan Shujie, Yicha Zhang, Nadia Labed, François Peyraut

doi:10.1016/j.ijsolstr.2024.112974

蜂窝晶格增材制造的多尺度周期均匀化

Additive manufacturing (AM) is revolutionizing how we create things, offering innovative solutions that rival traditional manufacturing methods. In Fused Filament Fabrication (FFF), incorporating continuous fiber-reinforced filaments has significantly enhanced mechanical properties, making them valuable across diverse sectors like aerospace, automotive, and robotics. However, before printing a part, numerical simulation for design verification is essential. Yet, there’s a lack of suitable tools for modeling the complex material properties, particularly for composite lattice structures. To address this, we propose a three-level periodic homogenization method. The first level focuses on modeling individual filaments, followed by characterizing inter-bead voids at the second level, and finally, modeling collective lattice behavior at the third level. Hexagonal cellular lattice composite structures were modeled and tested to confirm the method’s accuracy and its value in supporting simulation and modular design for the composite FFF process.

增材制造(AM)正在彻底改变我们创造事物的方式，提供与传统制造方法相媲美的创新解决方案。在熔融长丝制造(FFF)中，结合连续纤维增强长丝可以显着提高机械性能，使其在航空航天，汽车和机器人等不同领域具有价值。然而，在打印零件之前，进行设计验证的数值模拟是必不可少的。然而，缺乏合适的工具来模拟复杂的材料特性，特别是复合晶格结构。为了解决这个问题，我们提出了一种三能级周期均匀化方法。第一级侧重于对单个细丝进行建模，其次是在第二级描述晶间空隙，最后是在第三级对集体晶格行为进行建模。通过对六角形元胞点阵复合材料结构的建模和测试，验证了该方法的准确性及其对复合材料FFF过程仿真和模块化设计的支持价值。

The determination of the inclusion curing-induced nonlinear elastic field in photo-cured materials

Qiang Zhang, Yan Shi, Cunfa Gao

doi:10.1016/j.ijsolstr.2024.112978

光固化材料中夹杂物固化诱导的非线性弹性场的测定

A wide variety of photo-cured materials have recently been developed with the rapid advancement of three-dimensional (3D) printing technology. However, most of these materials are designed as soft functional materials, and their failure mechanisms have received little attention. This work studies the mesoscale residual stress defects of photo-cured materials that are generated due to non-uniform curing and volume shrinkage during the manufacturing process. The defects are simplified as uncured inclusions embedded within a fully cured, infinite matrix which are then additionally cured. A large deformation model, validated against finite element analysis, is established to determine the nonlinear elastic field induced by the curing of inclusions with different Poisson’s ratio and shape (i.e., sphere and axisymmetric ellipsoid), and is shown to outperform the infinitesimal strain model. This large deformation model, which includes a phase evolution constitutive model to describe the inclusion’s behavior and a compressible neo-Hookean model to describe the matrix’s behavior, is derived based on the same elastic field distribution as that in the infinitesimal strain solution and an ellipsoid-ellipsoid transformation kinematics assumption. The final solution is expressed in a discrete formulation and is exact for spherical inclusions and approximate for ellipsoidal inclusions. The prediction results of the theoretical model are compared with the finite element analysis, and reasonable agreement is obtained. This study may lay a foundation for investigating the effects of mesoscale residual stress defects on the mechanical behavior of 3D printing materials.

近年来，随着三维打印技术的飞速发展，各种各样的光固化材料被开发出来。然而，这些材料大多被设计为软功能材料，其失效机制很少受到关注。本文研究了光固化材料在制造过程中由于不均匀固化和体积收缩而产生的中尺度残余应力缺陷。将缺陷简化为嵌入在完全固化的无限基体中的未固化夹杂物，然后对其进行额外固化。建立了大变形模型，通过有限元分析验证了不同泊松比和形状(即球体和轴对称椭球体)夹杂物固化引起的非线性弹性场，结果表明该模型优于无穷小应变模型。该大变形模型基于与无穷小应变解相同的弹性场分布和椭球-椭球变换运动学假设，包括描述夹杂物行为的相演化本构模型和描述矩阵行为的可压缩新hookean模型。最终解用离散公式表示，对球形夹杂物是精确的，对椭球夹杂物是近似的。将理论模型的预测结果与有限元分析结果进行了比较，得到了合理的吻合。本研究为研究中尺度残余应力缺陷对3D打印材料力学行为的影响奠定了基础。

Journal of the Mechanics and Physics of Solids

Quasi-brittle ice breaking mechanisms by high-velocity water jet impacts: An investigation based on PD-SPH coupling model and experiments

Hao-Tian Shi, Guang-Yu Yuan, Bao-Yu Ni, Lu-Wen Zhang

doi:10.1016/j.jmps.2024.105783

基于PD-SPH耦合模型和实验的高速水射流准脆性破冰机制研究Ice, a quasi-brittle material with a complex crystal organization and found ubiquitously in nature, undergoes an impact fragmentation process that implies a rich physical mechanism, yet remains not thoroughly elucidated. We develop a highly robust and efficient meshless method for fluid-solid coupling, specifically designed to elucidate the mechanisms of crack propagation in S2 columnar ice subjected to high-speed water jet impacts. This method couples a low-dissipative Riemann smooth particle hydrodynamics approach with a non-ordinary state-based peridynamics model, enabling detailed exploration of fracture process. Our theoretical advancements enhance numerical stability at the fluid-solid interface and establish a precise ice constitutive model by capturing the unique hydrostatic pressure-dependent and rate-dependent plasticity within the peridynamics framework, effectively addressing challenges in both fluid and solid phases. Combined with high-velocity water jet impact experiments, this study successfully delineates the initiation and expansion of circumferential and radial cracks in ice plates. We demonstrate that these cracks, both circumferential and radial, originate from tensile failure induced by circular elastic–plastic stress waves initiated by point source shocks. Specifically, circumferential cracks emerge and propagate from the upper to the lower surface driven by radial tensile stress, while radial cracks, motivated by circumferential tensile stress, develop from the lower to the upper surface. This investigation not only provides a foundational understanding of ice impact fracturing but also establishes a versatile theoretical framework applicable to a wide range of quasi-brittle materials.

冰是一种具有复杂晶体结构的准脆性材料，在自然界中随处可见，它经历的冲击破碎过程意味着丰富的物理机制，但至今仍未得到彻底阐明。我们开发了一种高度稳健、高效的流固耦合无网格方法，专门用于阐明 S2 柱状冰在高速水射流冲击下的裂纹扩展机制。该方法将低耗散黎曼光滑粒子流体力学方法与基于非平凡状态的周流体力学模型结合起来，实现了对断裂过程的详细探索。我们的理论进展增强了流固界面的数值稳定性，并通过在周动力学框架内捕捉独特的静水压力依赖性和速率依赖性塑性，建立了精确的冰构成模型，从而有效地解决了流体和固体两相的难题。结合高速水射流冲击实验，这项研究成功地描述了冰板周向和径向裂缝的产生和扩展过程。我们证明，这些裂缝（包括周向和径向裂缝）源于点源冲击引发的环形弹塑性应力波所诱发的拉伸破坏。具体来说，在径向拉伸应力的驱动下，周向裂缝从上表面出现并向下表面扩展，而在周向拉伸应力的驱动下，径向裂缝则从下表面发展到上表面。这项研究不仅提供了对冰冲击断裂的基本认识，还建立了适用于各种准脆性材料的通用理论框架。

The selection mechanism of mineral bridges at the interface of stacked biological materials for a strength-toughness tradeoff

Zheyuan Yu, Yu Yan, Zhilong Peng, Yin Yao, Shaohua Chen

doi:10.1016/j.jmps.2024.105785

基于强度-韧性权衡的叠层生物材料界面矿物桥的选择机制

The strength-toughness tradeoff in biological materials such as nacre and bone is essentially due to their stacked microstructures formed by hard and soft phases. In some of these materials, purely soft phase acts as interface layers linking hard phases (platelets), while in some others, hard-phase bridges exist in the soft phase to form a hybrid interface. In order to disclose the selection mechanism of such different interface structures in biological materials, a novel shear-lag model with an interface consisting of alternatively distributed elasto-plastic (soft) and brittle-elastic (hard) segments is proposed. Using this model, solutions of tensile stress and tensile displacement in hard platelets and shear stresses in soft and hard interfacial segments are analytically achieved. Effects of the hybrid interface on the effective mechanical performances of the composite are analyzed, the results of which are well consistent with the existing experimental observations in biocomposites and bio-inspired composites. The most important finding is that the fracture strain of the soft phase has a decisive effect on the selection of a purely soft-phase interface or a hybrid interface of hard and soft phases in stacked biological materials in order to realize a tradeoff between strength and toughness. When the failure strain of the soft phase is relatively small, such as nacre, the purely soft-phase interface is too weak to transfer enough load to the platelet, and hard bridges are necessarily required to reinforce the interface and guarantee an efficient load transfer. When the soft phase has a sufficiently large failure strain, such as bone, the purely soft-phase interface is tough enough to sustain a large shear deformation, realizing an efficient load transfer and adequate utilization of all constituents, while an additional hard bridge is not conducive to the composite toughness due to its reducing effect on the interfacial shear deformation. The results not only help people gain a deeper understanding of the secrets behind the construction of different interfaces in biological materials, but also provide useful guidance for interface optimization design in strong and tough artificial materials.

生物材料的强度-韧性的权衡，如珍珠和骨本质上是由于其堆叠的微观结构形成的硬和软相。在其中一些材料中，纯软相作为连接硬相(血小板)的界面层，而在其他一些材料中，硬相桥存在于软相中以形成混合界面。为了揭示这种不同界面结构在生物材料中的选择机制，提出了一种新的剪切滞后模型，该模型的界面由弹塑性(软)段和脆弹性(硬)段交替分布组成。利用该模型，分析得到了硬薄片的拉应力和拉位移以及软、硬界面段的剪切应力的解。分析了杂化界面对复合材料有效力学性能的影响，结果与已有的生物复合材料和仿生复合材料的实验观察结果吻合较好。最重要的发现是，软相的断裂应变对选择纯软相界面或软硬相混合界面具有决定性的影响，从而实现强度与韧性之间的平衡。当软相的破坏应变相对较小时，如珠层，单纯的软相界面太弱，无法将足够的载荷传递给血小板，必须使用硬桥来加强界面并保证有效的载荷传递。当软相具有足够大的破坏应变时，如骨，纯软相界面具有足够的韧性来承受较大的剪切变形，实现有效的载荷传递和所有组分的充分利用，而额外的硬桥由于其对界面剪切变形的降低作用而不利于复合材料的韧性。研究结果不仅有助于人们更深入地了解生物材料中不同界面构造背后的秘密，而且对强韧性人工材料的界面优化设计提供了有益的指导。

International Journal of Plasticity

NN-EVP: A physics informed neural network-based elasto-viscoplastic framework for predictions of grain size-aware flow response

Adnan Eghtesad, Jingye Tan, Jan Niklas Fuhg, Nikolaos Bouklas

doi:10.1016/j.ijplas.2024.104072

NN-EVP:一个基于物理信息神经网络的弹粘塑性框架，用于预测晶粒尺寸感知的流动响应

We propose a physics informed, neural network-based elasto-viscoplasticity (NN-EVP) constitutive modeling framework for predicting the flow response in metals as a function of underlying grain size. The developed NN-EVP algorithm is based on input convex neural networks as a means to strictly enforce thermodynamic consistency, while allowing high expressivity towards model discovery from limited data. It utilizes state-of-the-art machine learning tools within PyTorch’s high-performance library providing a flexible tool for data-driven, automated constitutive modeling. To test the performance of the framework, we generate synthetic stress–strain curves using a power law-based model with phenomenological hardening at small strains and test the trained model for strain amplitudes beyond the training data. Next, experimentally measured flow responses obtained from uniaxial deformations are used to train the framework under large plastic deformations. Additionally, the Hall-Petch relationship corresponding to grain size strengthening is discovered by training flow response as a function of grain size, also leading to efficient extrapolation. Furthermore, a deployment framework of the discovered neural network constitutive laws is demonstrated with finite element analysis procedures. The present work demonstrates a successful integration of neural networks into elasto-viscoplastic constitutive laws, providing a robust automated framework for constitutive model discovery that can efficiently generalize, while also providing insights into predictions of flow response and grain size-property relationships in metals and metallic alloys under large plastic deformations.

我们提出了一个物理信息，基于神经网络的弹粘塑性(NN-EVP)本构建模框架，用于预测金属中的流动响应作为潜在晶粒尺寸的函数。开发的NN-EVP算法基于输入凸神经网络作为严格执行热力学一致性的手段，同时允许从有限数据中发现模型的高表达性。它利用PyTorch的高性能库中的最先进的机器学习工具，为数据驱动的自动本构建模提供了灵活的工具。为了测试框架的性能，我们使用基于幂律的模型在小应变下产生现象硬化的合成应力-应变曲线，并测试训练模型的应变幅值超出训练数据。接下来，实验测量的流动响应从单轴变形被用来训练框架下的大塑性变形。此外，通过训练流响应作为粒度的函数，发现了与粒度增强相对应的Hall-Petch关系，也导致了有效的外推。此外，利用有限元分析程序演示了所发现的神经网络本构规律的部署框架。目前的工作证明了神经网络与弹粘塑性本构律的成功集成，为本构模型发现提供了一个强大的自动化框架，可以有效地推广，同时也为大塑性变形下金属和金属合金的流动响应和晶粒尺寸-性能关系的预测提供了见解。

Thin-Walled Structures

First-order GBT for truncated conical shells with circular cross-section

Rodrigo Gonçalves, Mihai Nedelcu

doi:10.1016/j.tws.2024.112210

圆截面截锥形壳的一阶GBT

This paper presents a new and general first-order Generalized Beam Theory (GBT) formulation for thin truncated conical shells with circular cross-section. With respect to the previous formulations (Nedelcu, 2011; Mureşan et al., 2019), which were developed for the linear stability analysis case and therefore only required the consideration of rather simple load cases, the present one keeps all membrane strain terms and therefore is able to enforce the standard GBT membrane strain assumptions exactly. Even if the resulting expressions and the boundary conditions are more involved, it is shown that it is possible to define the so-called GBT “Vlasov warping deformation modes” also in the conical case, which are essential for the overall performance of the formulation. For instance, these deformation modes allow finding the shell inextensible deformation shapes. Several numerical tests are presented to show the excellent performance of the resulting finite element, through comparison with refined shell finite element models, and the advantages offered by the GBT modal decomposition features.

本文提出了一种新的、通用的一阶广义梁理论(GBT)公式。相对于之前的配方(Nedelcu, 2011;mure<e:1>等人，2019)，这是为线性稳定性分析案例开发的，因此只需要考虑相当简单的载荷情况，本例保留了所有膜应变项，因此能够准确地执行标准GBT膜应变假设。即使结果表达式和边界条件更复杂，也可以在锥形情况下定义所谓的GBT“弗拉索夫翘曲变形模式”，这对公式的整体性能至关重要。例如，这些变形模式允许找到外壳不可扩展的变形形状。通过与精化壳有限元模型的比较，以及GBT模态分解特征的优势，给出了若干数值试验，证明了所得到的有限元模型的优异性能。

Machine learning-based surrogate models for predicting the optimized weight and prestress level of double-curvature cable domes

Elshaimaa A. Ahmed, Ashraf A. El Damatty

doi:10.1016/j.tws.2024.112215

基于机器学习的双曲率索穹顶优化重量和预应力水平预测代理模型

A major challenge in designing cable domes is the high sensitivity of these lightweight flexible structures to geometry change. Including shape parameters with size of all elements and prestress level as discrete design variables in optimization algorithm may lead it to be computationally prohibitive. In this regard, this study employs and compares a multi-linear regression (MLR) model, a multiplicative non-linear regression (MNLR) model, and an artificial neural network (ANN) model with the aim to estimate the optimized prestress level at the minimum weight for different geometries of double-curvature cable domes. The models are trained using a large dataset of dome geometries developed and optimized numerically. The models show high accuracy with a slight advantage for ANN over MLR and MNLR. However, the prediction functions using MNLR model are much simpler and concise with only 7 coefficients when compared to a complete quadratic function of 28 terms needed in the MLR model and to the complexity of ANN equation. Moreover, unlike MLR and ANN, the MNLR model can synthetically generate a larger dataset of optimized values quite accurately beyond the trained range. The developed functions facilitate the prediction of the optimized prestress level and structural weight of double-curvature cable domes when compared to the traditional optimization algorithms. They can be utilized as a design support tool when implemented as a built-in library in design software. They also save time and effort when employed as an objective function for a shape optimization problem. Moreover, they fulfill designers’ preferences for the dome stiffness and load-bearing capacity. Finally, the impact of considered geometrical parameters on the optimized values is explored using the trained dataset, providing recommendations for designers.

设计索穹顶的一个主要挑战是这些轻质柔性结构对几何变化的高度敏感性。在优化算法中，将所有单元的尺寸和预应力水平的形状参数作为离散设计变量，可能会导致计算上的限制。为此，本研究采用多元线性回归(MLR)模型、乘法非线性回归(MNLR)模型和人工神经网络(ANN)模型并进行比较，以估计不同几何形状的双曲率索穹顶在最小重量下的优化预应力水平。这些模型是使用大型圆顶几何数据集进行训练的，这些数据集是通过数值方法开发和优化的。结果表明，该模型具有较高的精度，并且相对于MLR和MNLR具有一定的优势。然而，与MLR模型需要28项的完整二次函数和ANN方程的复杂性相比，使用MNLR模型的预测函数更简单简洁，只有7个系数。此外，与MLR和ANN不同，MNLR模型可以在训练范围之外相当精确地综合生成更大的优化值数据集。与传统的优化算法相比，所开发的函数可以方便地预测双曲索穹顶的优化预应力水平和结构重量。当在设计软件中作为内置库实现时，它们可以用作设计支持工具。当它们作为形状优化问题的目标函数时，也节省了时间和精力。满足了设计者对穹顶刚度和承载能力的要求。最后，使用训练好的数据集探索考虑的几何参数对优化值的影响，为设计师提供建议。

Odd mechanical metamaterials with simultaneously expanding or contracting under both compression and tension

Xiaojun Tan, Bo Cao, Wencheng Liu, Chunming Ji, Bing Wang, Shuai Li

doi:10.1016/j.tws.2024.112225

在压缩和拉伸下同时膨胀或收缩的奇异机械超材料

Mechanical metamaterials with negative Poisson's ratio have attracted widespread attention in recent decades due to their unique mechanical properties. This metamaterial often exhibits the characteristic of expansion under tension and contraction under compression, which is different from traditional materials. Currently, almost all related research is focused on the design and further application of such metamaterials. This paper proposes a class of odd mechanical metamaterials, which can exhibit characteristics of expanding (or contracting) under both compression and tension, with the Poisson's ratio showing strong directional dependence. Experimental and simulation methods were employed to verify the conceptual ideas presented in this study, and corresponding three-dimensional and cylindrical shell structures were proposed. The mechanical metamaterials that expand under both compression and tension are ideal scaffolds for human esophagus/vessels, which can ensure the smooth flow of blood and nutrients. And the metamaterials that contract under both compression and tension were prefect choice in bone/gristle repair field, which doesn't compress surrounding tissues and nerves during loading. This study further enriches the understanding of the mechanical metamaterials with negative Poisson's ratio and provides more possibilities for the design of such metamaterials.

具有负泊松比的机械超材料由于其独特的力学性能在近几十年来引起了广泛的关注。这种超材料往往表现出受拉膨胀、受压缩收缩的特性，这与传统材料不同。目前，几乎所有的相关研究都集中在这种超材料的设计和进一步应用上。本文提出了一类奇异力学超材料，它在压缩和拉伸下都能表现出膨胀(或收缩)的特性，且泊松比具有很强的方向依赖性。采用实验和仿真方法验证了本文提出的概念，并提出了相应的三维和圆柱壳结构。这种在压缩和拉伸下都能膨胀的机械超材料是人体食管/血管的理想支架，可以保证血液和营养物质的顺畅流动。同时在压缩和拉伸下收缩的超材料在加载过程中不会压迫周围组织和神经，是骨/软骨修复领域的理想选择。本研究进一步丰富了对负泊松比机械超材料的认识，为负泊松比机械超材料的设计提供了更多的可能性。

Quasi-static bending analysis of composite laminated cylindrical panels under hygrothermal conditions

Seyed Mohammadreza Ostadzadeh, Ali Mohammad Baghestani, Hamed Afrasiab, Meghdad Gholami

doi:10.1016/j.tws.2024.112227

复合材料层合柱板在湿热条件下的准静态弯曲分析

The combined effects of temperature and humidity, termed hygrothermal, are included in the deformation analysis of laminated composite cylindrical panels based on first-order shear deformation theory (FSDT). The panel is under transverse mechanical load, and both steady-state and transient hygrothermal loads are considered. The problem is solved using the minimum potential energy theorem for different boundary conditions. The moisture profile through the thickness is obtained by analytical solution of Fick diffusion equation. The dependency of moisture diffusion coefficient on temperature is considered and the material temperature is assumed to be the same as the environmental temperature. Using a semi-analytical approach, displacement field of the panel subjected to evaluated profile of moisture in a specific time and thermo-mechanical loads is obtained. The accuracy and validation of the present solution are demonstrated by solving numerical examples and comparing them with the results available in the literature. Furthermore, new results are presented and effects of various important parameters such as panel geometry, edge boundary conditions, lamination layups and imposed moisture conditions on the deformation of the composite cylindrical panel are studied. Solved examples demonstrate that higher length-to-arc and radius-to-thickness ratios result in increased deflection and amplify the influence of mechanical load compared to hygrothermal effects on the overall deformation of the panel. In most case studies, the hygroscopic deformation observed at one-tenth of the saturation time exceeded half of the deformation observed after the saturation time, which shows the importance of transient hygroscopic analysis.

基于一阶剪切变形理论(FSDT)对层合复合材料柱状板进行变形分析，考虑了温度和湿度的综合影响，即湿热效应。面板承受横向机械载荷，同时考虑稳态和瞬态湿热载荷。在不同的边界条件下，利用最小势能定理求解了该问题。通过菲克扩散方程的解析解，得到了随厚度变化的水分分布。考虑了水分扩散系数对温度的依赖关系，并假设材料温度与环境温度相同。采用半解析的方法，得到了薄板在特定时间和热机械载荷作用下的位移场。通过数值算例的求解，并与文献中已有的结果进行了比较，证明了本文解的准确性和有效性。在此基础上，研究了板的几何形状、边缘边界条件、层合层数、外加水分条件等重要参数对复合圆柱板变形的影响。解算实例表明，与湿热效应相比，较高的长弧比和半径厚度比会导致挠度增加，并放大机械载荷对面板整体变形的影响。在大多数案例研究中，在十分之一饱和时间观察到的吸湿变形超过了饱和时间后观察到的变形的一半，这表明瞬态吸湿分析的重要性。

Dynamic analysis of an inflatable space structure with moving masses described by ALE-ANCF

Hao Du, Dongping Jin, Jialiang Sun

doi:10.1016/j.tws.2024.112229

具有运动质量的充气空间结构的动力学分析

A new dynamic model of the inflatable space structure with moving masses has been established which uses the variable-length shell element of absolute nodal coordinate formulation (ANCF) in the framework of arbitrary Lagrange-Euler (ALE) to estimate the dynamic responses of spinning inflatable spacecraft on orbit. Compared with the traditional ANCF method, the developed ALE-ANCF method can not only describe the large overall motions and large deformations of the inflatable structures, but also account for the variable length induced by the moving mass through the introduction of two material coordinates. The orbital dynamics and the linearized characteristic equations of the rigid-flexible multibody system are derived, with the Coriolis force, universal gravitation and centrifugal force taken into consideration. The dynamic characteristics of the inflatable space structure with moving masses are studied and a vibration experiment is conducted to verify the accuracy of the dynamic model. The orbital dynamic responses of the inflatable space structure with moving masses are analyzed.

在任意拉格朗日-欧拉(ALE)框架下，利用绝对节点坐标公式的变长壳元估计轨道上旋转充气航天器的动力响应，建立了具有运动质量的充气空间结构动力学模型。与传统的ANCF方法相比，所开发的ALE-ANCF方法不仅可以描述充气结构的大整体运动和大变形，而且通过引入两个材料坐标来考虑运动质量引起的长度变化。推导了考虑科里奥利力、万有引力和离心力的刚柔多体系统的轨道动力学和线性化特征方程。研究了具有运动质量的充气空间结构的动力特性，并进行了振动实验，验证了动力学模型的准确性。分析了具有运动质量的充气空间结构的轨道动力响应。

A semi-analytical electromechanical model for energy harvesting of plate with acoustic black hole indentations

Weiqi Du, Zijian Xiang, Xiaobiao Qiu

doi:10.1016/j.tws.2024.112235

带声黑洞压痕板能量收集的半解析机电模型

Acoustic black hole (ABH) has been proved to be helpful for the energy harvesting of beam. Since thin plates are more widely used in practical engineering, it is of great significance to explore the energy harvesting with ABH effect applying to thin plate. Therefore, a piezoelectric plate with ABH indentations is designed and a standard full-wave rectifier circuit connected to the energy harvester in this paper. A semi-analytical electromechanical model is proposed for the energy harvesting system and Gaussian basis functions are used to solve the coupled electromechanical equations. The harvested power is calculated with the proposed method and the acceptable accuracy could be found through the validation against finite element simulation. Finally, a comprehensive analysis has been performed and numerical results show the system parameters (such as piezoelectric layer parameters, ABH parameters, and circuit parameters) have a significant influence on the energy harvesting.

声学黑洞(ABH)已被证明有助于光束的能量收集。由于薄板在实际工程中的应用越来越广泛，因此研究利用ABH效应在薄板上进行能量收集具有重要意义。因此，本文设计了带ABH压痕的压电片，并将标准的全波整流电路连接到能量采集器上。提出了能量收集系统的半解析式机电模型，并采用高斯基函数求解耦合机电方程。用所提出的方法计算了收获功率，并通过有限元仿真验证了其精度。最后，进行了综合分析，数值结果表明，系统参数(如压电层参数、ABH参数和电路参数)对能量收集有显著影响。

Testing, modelling and design of laser-welded stainless steel slender I-section beam-column members under combined compression and major-axis bending

Hongdong Ran, Zhilong Tang, Yibo Wang, Xi Chen, Zhanpeng Chen, Yao Sun

doi:10.1016/j.tws.2024.112238

激光焊接不锈钢细长工字截面梁柱受压与主轴弯曲联合作用试验、建模与设计

This paper presents testing and modelling investigations on laser-welded stainless steel slender I-section beam-column members under combined compression and major-axis bending moment, which are susceptible to torsional-flexural buckling interacting with local buckling. A testing programme was firstly conducted, including material tests, imperfection measurements and beam-column tests. Upon completion of laboratory tests, a numerical modelling programme was carried out, in which finite-element models were developed and validated based on the test results. The numerical models were then used to perform parametric studies to derive more beam-column data. The obtained test and numerical data were adopted to conduct a design analysis, in which the relevant interaction curves in the American and European standards were evaluated. The analysis results show that the American and European standards lead to inaccurate resistance predictions, especially for beam-column members subjected to eccentric compression with large eccentricity, due to the conservative bending end-points that are specified for the design of beams prone to lateral-torsional buckling. A new interaction curve was proposed based on the continuous strength method and found to provide improved design accuracy and consistency over the current American and European standards.

本文对激光焊接不锈钢细长工字钢梁柱构件在压缩和主轴弯矩联合作用下易发生扭弯屈曲和局部屈曲的试验和模型研究。首先进行了测试程序，包括材料测试、缺陷测量和梁柱测试。在完成实验室测试后，开展了数值模拟方案，根据测试结果开发和验证了有限元素模型。然后使用数值模型进行参数化研究，以获得更多的梁柱数据。采用得到的试验数据和数值数据进行设计分析，并对美欧标准中的相关相互作用曲线进行了评价。分析结果表明，美国和欧洲的标准导致抗力预测不准确，特别是对于大偏心受压的梁柱构件，由于规定的弯曲端点保守，梁的设计容易发生侧向扭转屈曲。基于连续强度法提出了一种新的相互作用曲线，与现行美欧标准相比，具有更高的设计精度和一致性。